Download Zevalin Prolongs Survival in NHL Patients Background: Follicular

Zevalin Prolongs Survival in NHL Patients
Rationale for Consolidation to Improve Progression-Free Survival in Patients With Non-Hodgkin’s Lymphoma: A Review
of the Evidence.
Morschhauser F, Dreyling M, et al:
Oncologist 2009; 14 (Supplement 2): 17-29
Consolidation therapy with Zevalin can prolong survival in patients with follicular non-Hodgkin lymphoma.
Background: Follicular lymphoma (FL) and diffuse large cell lymphoma (DLCL) are the most common
histologic types of non-Hodgkin lymphoma (NHL). For both of these tumor categories, patients who achieve a
complete remission (CR), as opposed to partial remission (PR), following frontline chemotherapy have better
overall and progression-free survival. Consequently, initial treatment paradigms for NHL should focus on the
induction of a complete initial remission.
Objective: The authors of this review present the relevant data from clinical trials regarding use of
radioimmunotherapy (RIT) as a frontline treatment along with chemotherapy for patients with NHL.
Results: In some cases, maintenance therapy with rituximab is effective in maintaining a CR. However,
multiple phase II studies with either 90Y-ibritumomab (Zevalin®) or 131I-tositumomab (Bexxar®) have
demonstrated the effectiveness of these agents in patients with FL for producing a CR when response to initial
chemotherapy has only been a PR. Conversion rates have been reported to be between 49% and 84%. This
approach is often referred to as “consolidation therapy.” A large phase III randomized trial (414 subjects) using
90Y-ibritumomab as frontline consolidation has confirmed these earlier findings and also demonstrated a
dramatic increase in progression-free survival (from 13 to 36 months) with 90Y-ibritumomab. Moreover, for
patients with persistently positive bcl-2 disease after induction chemotherapy, 90Y-ibritumomab consolidation
prolonged progression-free survival by 30 months. A similar phase III trial is ongoing with Bexxar. There is less
data available pertaining to the use of these agents as consolidation therapy in frontline treatment for
individuals with DLCL. However studies are ongoing and initial results are very encouraging.
Conclusions: The authors conclude that, “Data from clinical trials suggest that RIT consolidation therapy is an
important treatment approach for patients with FL, with striking phase III results recently published for 90Yibritumomab tiuxetan consolidation following induction therapy in previously untreated patients.”
Reviewer's Comments: We have talked about this before, but it certainly appears that RIT will become a
standard part of the initial treatment paradigm for FL and perhaps for DLCL as well. It has been approved for
this use now in both Europe and the United States. (Reviewer-David Bushnell, MD).
© 2009, Oakstone Medical Publishing
Keywords: Non-Hodgkin Lymphoma, Radioimmunotherapy
Print Tag: Refer to original journal article
MI Prevalence Significantly Increased With Type-2 Diabetes
Myocardial Ischemia, Carotid, and Peripheral Arterial Disease and Their Interrelationship in Type 2 Diabetes Patients.
Poulsen MK, Henriksen JE, et al:
J Nucl Cardiol 2009; 16 (November-December): 878-887
In patients with type 2 diabetes, signs of cardiovascular disease in 1 vascular territory are significantly
associated with an increased risk of disease in other vascular territories, although many patients show
disease in only 1 location.
Background: The frequency of cardiovascular disease in >1 vascular territory in patients with type 2 diabetes
mellitus (T2DM) has not been well evaluated. Studies applying myocardial perfusion scintigraphy (MPS) in
asymptomatic patients with T2DM have reported a prevalence of silent myocardial ischemia (MI) ranging from
17% to 59%; a prevalence of carotid arterial disease of about 46%; and a prevalence of peripheral arterial
disease ranging from 1% to 29% (range highly dependent on diabetes duration).
Objective: To determine the prevalence and interrelationship between observed cardiovascular disease as
measured by MPS, carotid ultrasonography (US), and systolic ankle-brachial index (ABI) in patients with
T2DM.
Design: Prospective cohort study.
Participants: 305 patients who had T2DM of <5 years’ duration and an age-matched reference group of 40
patients without diabetes.
Methods: Both groups were screened for cardiovascular disease in 3 vascular territories: for MI using MPS,
for carotid vessel wall changes using B-mode US, and for peripheral arterial disease using the ABI and toebrachial systolic blood pressure index. Adenosine stress testing was performed in 265 of 305 patients with
T2DM and in 39 of 40 reference group patients.
Results: Patients with T2DM were significantly more likely to have silent MI (T2DM, 30%; controls, 10%), a
carotid intima media thickness >1 mm at any location (T2DM, 35%; controls, 8%), carotid plaque at any
location (T2DM, 21%; controls, 5%), or any indication of carotid arterial disease (plaque or intima thickening:
T2DM, 42%; controls, 13%). Diabetics with disease in 1 vascular territory had a significantly increased risk of
disease in other vascular territories. If examining exclusively for carotid arterial disease, 48% of patients with
MI would have been missed. If examining for peripheral arterial disease only, 78% of patients with MI would
have been missed. The average duration of T2DM in the study population was 4.5 ± 5.3 years.
Conclusions: Patients with type T2DM and vascular disease in 1 territory have a significantly increased risk of
having disease elsewhere. However, many patients present with disease in 1 location only.
Reviewer's Comments: When screening for cardiovascular disease in patients with T2DM, looking at only MI,
carotid arterial disease, or peripheral arterial disease will frequently miss disease in the other vascular
territories. The prevalence of silent MI was 30% in patients with T2DM of <5 years’ average duration.
(Reviewer-Thomas F. Heston, MD).
© 2009, Oakstone Medical Publishing
Keywords: Myocardial Perfusion Scintigraphy, Type 2 Diabetes
Print Tag: Refer to original journal article
MPS Stratifies Risk of Cardiac Death in Elderly
Prognostic Implications of Myocardial Perfusion Single-Photon Emission Computed Tomography in the Elderly.
Hachamovitch R, Kang X, et al:
Circulation 2009; 120 (December 1): 2197-2206
In patients aged ≥75 years, the percentage of ischemic left ventricular myocardium identified on
myocardial perfusion scintigraphy identifies which patients can expect a mortality benefit from
revascularization.
Background: Elderly patients (≥75 years of age) constitute 6.1% of the population but suffer two-thirds of all
cardiovascular deaths. The elderly are a heterogeneous population in which coronary disease frequently
presents with silent ischemia, atypical angina, or nonspecific functional deterioration, making the identification
of high-risk patients difficult. Thus, stress imaging may play an important role in the identification of high-risk
individuals and be important in guiding post-test medical management.
Objective: To assess the clinical value of stress myocardial perfusion scintigraphy (MPA) in the elderly.
Design: Retrospective cohort review.
Participants: The initial population was 5887 elderly patients referred for stress MPS for clinical reasons from
1991 to 1999. Exclusion criteria were patients with known nonischemic cardiomyopathy or valvular disease,
those lost to follow-up, and those undergoing early revascularization (within 60 days of imaging). The final
study population consisted of 5200 elderly patients.
Methods: Patients underwent dual-isotope MPS, with approximately 50% undergoing gated MPS. Cardiac
death was defined as death from any cardiac cause, including lethal arrhythmia, MI, or sudden death. Average
follow-up was 2.8 ±1.7 years.
Results: Perfusion defects (both fixed and reversible) and left ventricular ejection fraction added incrementally
to pre-test risk stratification. Compared with cardiac death rates of the age-matched population in the United
States, patients with a normal scan had approximately one-third the risk. Increasing ischemia was associated
with increased survival with early revascularization, whereas in the setting of little or no ischemia, medical
therapy was associated with improved outcomes.
Conclusions: Stress MPS yielded effective risk stratification for cardiac death in patients aged ≥75 years.
Importantly, perfusion scintigraphy also appears to be effective in guiding post-test medical management.
Reviewer's Comments: In this group of patients aged ≥75 years, only percentage of ischemic left ventricular
myocardium was able to identify which patients would expect a mortality benefit from revascularization. Those
with a reversible perfusion defect affecting <15% of the left ventricular myocardium did better with medical
therapy (47% predicted mortality) than with revascularization (53% predicted mortality), while those with ≥15%
ischemia did better with revascularization (47% predicted mortality) than with medical therapy (58% predicted
mortality) in terms of all-cause mortality. (Reviewer-Thomas F. Heston, MD).
© 2009, Oakstone Medical Publishing
Keywords: Myocardial Perfusion Imaging, Elderly, Prognosis
Print Tag: Refer to original journal article
Washout Slower for Mets Than for Adrenal Adenomas
Adrenal Mass Imaging With Multidetector CT: Pathologic Conditions, Pearls, and Pitfalls.
Johnson PT, Horton KM, Fishman EK:
Radiographics 2009; 29 (September-October): 1333-1351
Adrenal adenomas are typically less radiodense than adrenal metastases. After contrast administration,
adrenal metastases demonstrate a slower washout on delayed images than do adenomas.
Background: Many physicians who interpret PET/CT exams are faced with evaluation of CT findings as well
as PET.
Objective: In this review article, the authors examine the CT findings associated with various types of adrenal
tumors.
Results: The following is a summary of the salient points from this article. Enlarged and/or nodular adrenal
glands are not uncommon and may be seen in up to 18% to 23% of the population. Although many types of
primary and metastatic malignancies may occur in the adrenal glands, the most common tumor is the adrenal
adenoma, which may be present in 7% of patients aged >70 years. Lipid-rich adenomas may range in
attenuation from -2 to 16 HU, while lipid-poor tumors have been reported with an attenuation as high as 25 HU.
Moreover, up to 40% of adenomas are considered lipid-poor in nature. On diagnostic CT, adenomas exhibit
relatively rapid contrast washout compared to other adrenal tumors. Adrenocortical carcinomas often present
as large masses often >6 cm that appear inhomogeneous on non-contrast CT. Pheochromocytomas may be
benign or malignant and account for <1% of adults with hypertension. They appear as a unilateral or bilateral
CT mass with low attenuation that enhances brightly with IV contrast. Myelolipoma is a benign tumor of the
adrenal glands which can be identified on CT when fat is seen in a well-defined adrenal mass. Primary
malignancies with a propensity to metastasize to the adrenal include the lymphomas along with lung, gastric,
esophageal, hepatobiliary, pancreatic, colon, renal, and breast cancers. Non-contrast attenuation has been
reported to range from 14 to 55 HU in metastases to the adrenal glands.
Reviewer's Comments: This article has a number of excellent images that make it of value, especially for
those who are interpreting the CT component of the PET/CT exam. I have noticed that, as I have become
more familiar with CT interpretation, it seems as though my ability to interpret PET findings has improved.
(Reviewer-David Bushnell, MD).
© 2009, Oakstone Medical Publishing
Keywords: Adrenal Tumors, CT
Print Tag: Refer to original journal article
Myocardial SPECT in Less Than 5 Minutes
Wide Beam Reconstruction “Quarter-Time” Gated Myocardial Perfusion SPECT Functional Imaging: A Comparison to
“Full-Time” Ordered Subset Expectation Maximum.
DePuey EG, Bommireddipalli S, et al:
J Nucl Cardiol 2009; 16 (September-October): 736-752
Resolution recovery algorithms are now available from all the major SPECT manufacturers as well as
several independent vendors.
Background: Conventional SPECT myocardial perfusion studies require 10 to 15 minutes of acquisition time,
which reduces throughput and is often uncomfortable for patients.
Objective: To evaluate a version of the Wide-Beam Reconstruction (WBR™) software from UltraSPECT®.
The software was applied to myocardial SPECT studies that were acquired for approximately 25% of the
normal acquisition time (“quarter-time”).
Methods: The WBR algorithm was optimized for low count density studies by introducing new penalty
functions for the low pass filters. This software was first validated on a pilot group consisting of 48 subjects.
The main study group consisted of 209 patients who underwent gated stress and non-gated rest myocardial
perfusion SPECT studies. Full-time rest studies were acquired for 14 minutes, with a quarter-time acquisition of
4.5 minutes. The full-time stress studies were acquired for 12.3 minutes, with a quarter-time stress acquisition
of 4 minutes. A simulated resting set corresponding to half-time acquisition was generated using conditional
Poisson sampling of the full-time data. The full-time data sets were reconstructed with standard ordered subset
expectation maximization (OSEM) iterative reconstruction with post-filtering parameters. The quarter-time data
and simulated half-time sets were reconstructed with the optimized WBR software with no post-filtering
parameters. All reconstructed data sets were separately analyzed by 3 different commercial cardiac analysis
packages: GE Myometrix®, Emory Toolbox®, and QGS® from Cedars Sinai Medical Center. Image quality
was judged using a 5-point scale
Results: Although there was no significant quality difference between the full- and quarter-time resting images,
the quarter-time stress image quality was rated superior to the full-time stress images. However, the quartertime images were more likely to contain artifacts, such as apical streaks. In the large patients, the simulated
half-time rest images fared best but also were more susceptible to artifacts than the full-time images. The
summed stress scores were nearly identical between the full- and quarter-time image sets. The left ventricular
ejection fraction (LVEF) from the quarter-time studies had a strong correlation with the full-time LVEF results,
but it was systematically 5% to 15% lower. Regional wall motion analysis was similar with the 2 data sets.
Conclusions: The application of the optimized WBR software allows for reduced acquisition times down to
25% of the conventional imaging time without compromising the diagnostic performance of the test.
Reviewer's Comments: This result again demonstrates the potential for resolution recovery to provide
improvements in image quality that can be used to reduce acquisition times, administered activity, or both.
(Reviewer-Mark T. Madsen, MD).
© 2009, Oakstone Medical Publishing
Keywords: Myocardial Perfusion SPECT, Acquisition Time
Print Tag: Refer to original journal article
Targeted Therapies Recommended for Metastatic Thyroid Cancer
The 2009 American Thyroid Association Guidelines for Management of Thyroid Nodules and Differentiated Thyroid
Cancer: Progress on the Road from Consensus- to Evidence-Based Practice.
Puxeddu E, Filetti S:
Thyroid 2009; 19 (November): 1145-1147
New targeted therapies, such as anti-angiogenic tyrosine kinase inhibitors, are recommended by the new
American Thyroid Association guidelines for progressive metastatic disease unresponsive to I-131.
The American Thyroid Association (ATA) has published its “Revised Management Guidelines for Patients With
Thyroid Nodules and Differentiated Thyroid Cancer.” For preoperative staging, the new guidelines classify
cases into low-, intermediate-, and high-risk categories. Low-risk is defined as no local or distant metastases,
complete surgical removal with no residual tumor, no tumor invasion, and nonaggressive histology. High-risk is
defined as tumor invasion, incomplete resection, or distant metastases. Intermediate-risk is defined as
microscopic extra-thyroidal invasion, lymph node metastases, aggressive histology, and vascular invasion.
Recommendations for I-131 (radioiodine [RAI]) ablation of tumor remnants have been revised substantially.
RAI ablation is now advocated in patients with distant metastases and/or tumors that are grossly invasive or >4
cm. RAI ablation is not recommended for unifocal cancer <1 cm or for multifocal cancer with all foci measuring
<1 cm, unless there are other risk features. RAI ablation for intermediate-sized noninvasive cancers (1 to 4 cm)
confined to the thyroid is determined by lymph node metastases or when other considerations, such as age
and individual histology, predict an intermediate- to high-risk of recurrence. A special section of the published
guidelines is devoted to recently expanded indications for FDG-PET. For treatment of metastatic disease, the
new guidelines offer 3 strategies for I-131 dose selection: fixed doses, upper limit of blood and body dosimetry,
and quantitative tumor dosimetry. The recommendations limit I-131 dose to 200 mCi in patients aged >70
years. Data from phase II trials are promising regarding the use of new targeted therapies, such as
antiangiogenic tyrosine kinase inhibitors, for progressive or symptomatic metastatic disease that is
unresponsive to RAI. The new guidelines actually recommend these antiangiogenic tyrosine kinase inhibitors
over cytotoxic chemotherapy even if enrollment in a regional clinical trial is unavailable.
Reviewer's Comments: Interest in thyroid cancer is gaining popularity in the United States and Europe
because of its rapidly increasing incidence in young people, resulting in an even greater growth in prevalence.
The unexpected publication of revised guidelines by the ATA after so short a period (the last came out barely 3
years ago) attests to the proliferation of data permitting more evidence-based practice. It is important for
nuclear medicine physicians to make an active effort to keep up with the entire field of thyroid cancer practice,
including new genetic markers and targeted therapies that impact directly or indirectly on the use of I-131, I123, and PET FDG. (Reviewer-C. Richard Goldfarb, MD).
© 2009, Oakstone Medical Publishing
Keywords: Thyroid Nodules, Differentiated Thyroid Cancer, Management
Print Tag: Refer to original journal article
New Guidelines Recommend Pre-Ablation Scans
Highlights of the American Thyroid Association Guidelines for Patients With Thyroid Nodules or Differentiated Thyroid
Carcinoma: The 2009 Revision.
Wartofsky L:
Thyroid 2009; 19 (November): 1139-1143
European guidelines published some time ago questioned the value of pre-ablation whole body
radioiodine diagnostic scans. The new American Thyroid Association guidelines recommend pre-ablation
diagnostic scans.
The American Thyroid Association (ATA) has updated the 2006 guidelines on thyroid nodules and cancer. For
the first time, the 2009 guidelines include molecular markers, such as galectin-3 and BRAF. The new
guidelines do not recommend routine ablation in multifocal microcarcinoma or for a single tumor <1 cm unless
there are higher risk factors or a histological variant. Regarding thyroid hormone withdrawal in preparation for
ablation, T4 may be resumed on the second or third day after the I-131 is given. But since TSH after
withdrawal may remain high for 1 to 2 weeks after resumption of thyroid hormone, and because TSH induces
discharge of bound I-131 from thyroid remnant or thyroid cancer and consequentially reduces therapeutic
efficiency, it is more logical to restart the patient on T4 within 12 hours of therapy. Thyrogen was approved for
preparation of ablation in December 2007, and this approach is “strongly recommended” by the guidelines. No
distinction is made between ablation for Stage I versus Stage III or IV disease. Of significance is the lower
radiation dose that occurs to the whole body with Thyrogen than that which occurs by withdrawal. European
guidelines question the value of pre-ablation diagnostic scans because of a potential risk of stunning and the
notion that the post-therapy scan provides all needed information. Actually, I-131 scanning avoids the risk of
stunning, and the pre-therapy scan helps guide ablation. The new ATA guidelines recommend pre-ablation
diagnostic scans. They retain the 2006 recommendation for I-131dosages of 30 to 100 mCi for low-risk tumors
and 100 to 200 mCi for higher risk tumors. Also unchanged is the recommendation of a low-iodine diet for 1 to
2 weeks prior to ablative therapy, with a spot urine iodine test to ensure compliance. Patients undergoing a
low-iodine diet prior to radioiodine therapy may suffer dangerous hyponatremia due to mistaken avoidance of
all salt rather than avoiding only iodized salt. A new recommendation includes the use of PET in the
thyroglobulin-positive and scan-negative patient.
Reviewer's Comments: The practice in our institution changed over the past few years in accordance with the
new guidelines and well before they were published. We advocate radioiodine imaging in all patients prior to
ablation, finding it valuable to tailor I-131 doses for a given patient. We are using Thyrogen to prepare patients
for both imaging and ablation. The problem occurs when insurance companies balk at providing funding for so
much Thyrogen. Hopefully, the new ATA guidelines will reduce the resistance. (Reviewer-C. Richard Goldfarb,
MD).
© 2009, Oakstone Medical Publishing
Keywords: Thyroid Nodules, Differentiated Thyroid Carcinoma, Management
Print Tag: Refer to original journal article
V/Q Scanning Better Choice for Detecting PE
Diagnosing PE: Is V/Q Imaging a Better Choice Especially for Younger Women?
Orenstein BW:
Radiology Today 2009; 10 (October 19): 14-18
The potential long-term risks from CT radiation merit considering the use of ventilation/perfusion scanning
for the diagnosis of PE in patients with clear chest x-rays.
Until 10 years ago, scintigraphy was the imaging test of choice to diagnose pulmonary embolism (PE). During
the current decade, CT angiography (CTA) has become the new gold standard for imaging PE. CT is more
rapid, produces sharper images, and, at most hospitals, and is available 24/7, while nuclear medicine
technicians may not be on call. But Dr. Len Freeman has preached and published on the need to increase
utilization of the ventilation/perfusion (V/Q) scan for PE diagnosis. CT involves excessive radiation to the
female breast — the breast receives between 65 to 200 times greater radiation than from V/Q scintigraphy.
The potential long-term risks from CT radiation merit considering the use of V/Q for diagnosing PE whenever
possible. A pretest algorithm can select patients for CT versus nuclear medicine when PE is suspected. A plain
chest x-ray can triage patients in the emergency room. A patient with negative chest x-ray in whom PE is still
suspected should have a V/Q study. Patients with a positive x-ray showing pneumonia, pleural fluid, or
significant chronic disease go for CTA. Current practice uses V/Q for PE patients with contrast allergies and/or
renal impairment. Some now would add patients with normal chest x-rays because radiation exposure is a
concern. The younger the patient exposed to ionizing radiation, the more radiosensitive her breast tissue and
the more time to develop cancer. Drs. Freeman and Haramati reported that using chest x-ray for triage in the
ER results in 60% of PE studies being V/Q. SPECT-V/Q produces even clearer results and has become
standard practice in Europe where Technegas, a superior ventilatory SPECT agent, is available. Dr. Freeman
expects the Food and Drug Administration to approve Technegas in the next year or two.
Reviewer's Comments: The case certainly seems compelling for use of lung scintigraphy to diagnose PE in
patients with clear chest x-rays, especially in women of childbearing age. We recently ran a 1-year follow-up of
our low-probability scans for emergency room patients. We found no PE-associated mortality for patients
returning with repeat PEs. If these patients were all submitted to angiography or even spiral CT, small and
apparently clinically insignificant PEs would have been discovered in up to 15% of the patients. Many of these
would have been put on anticoagulation with its attendant risks of no apparent clinical benefit. (Reviewer-C.
Richard Goldfarb, MD).
© 2009, Oakstone Medical Publishing
Keywords: Pulmonary Embolism, V/Q Imaging
Print Tag: Refer to original journal article
FDG-PET Predicts Prognosis in Pediatric HL
Early and Late Therapy Response Assessment With [18F]Fluorodeoxyglucose Positron Emission Tomography in
Pediatric Hodgkin’s Lymphoma: Analysis of a Prospective Multicenter Trial.
Furth C, Steffen IG, et al:
J Clin Oncol 2009; 27 (September 10): 4385-4391
FDG-PET during and after chemotherapy can predict prognosis in children with Hodgkin lymphoma.
Ongoing studies in Europe aim to determine if radiotherapy can be eliminated in PET-negative patients.
Background: Adults with Hodgkin lymphoma (HL) who demonstrate early response based on FDG-PET have
an excellent prognosis. The application of PET in this clinical setting in children is lacking. Moreover, in
children, the use of radiotherapy for HL is associated with a high rate of secondary malignancies.
Consequently, it has been hoped that using PET might identify individuals who do not require adjuvant
radiotherapy.
Objective: The authors used PET to evaluate early and late response to therapy in children with HL.
Design: FDG-PET was performed in 40 subjects with HL at baseline and then again following 2 cycles of
chemotherapy and after completion of chemotherapy in the patients with advanced-stage disease.
Radiotherapy was delivered to 39 of the 40 patients.
Results: Early PET was negative in 26 of the 40 subjects, whereas conventional imaging remained positive in
25 of these individuals. During a mean follow-up of 45 months, none of the individuals with negative PET
presented with relapse. In contrast, 2 of the 14 PET-positive patients relapsed within 2 years of treatment. The
authors found a significantly higher risk of relapse in patients with a reduction in standard uptake value (SUV)
of <58%. In the 29 patients with advanced-stage disease, late PET was negative in 21. None of these 21
patients relapsed during a mean follow-up of 48 months. Of the 8 late PET-positive patients, 2 relapsed within
2 years.
Conclusions: The authors conclude by saying, “Early and late therapy response assessment by FDG-PET
helps to identify pediatric HL patients with an excellent prognosis who might benefit from de-escalation of
antineoplastic therapy.” They go on to note that ongoing studies in Europe aim to determine if radiotherapy can
be eliminated in PET-negative patients.
Reviewer's Comments: PET is used less in pediatric oncology than it is for adults, but, more and more, we
are seeing studies such as this one which support the value of metabolic imaging in this patient population.
(Reviewer-David Bushnell, MD).
© 2009, Oakstone Medical Publishing
Keywords: Hodgkin Lymphoma, PET
Print Tag: Refer to original journal article
Astonish Algorithm Improves Image Quality
A Multicenter Evaluation of a New Post-Processing Method With Depth-Dependent Collimator Resolution Applied to FullTime and Half-Time Acquisitions Without and With Simultaneously Acquired Attenuation Correction.
Venero CV, Heller GV, et al:
J Nucl Cardiol 2009; 16 (September-October): 714-725
In addition to improving throughput, half-time gated myocardial perfusion imaging can be expected to
improve image quality through the reduction of motion artifacts.
Background: Conventional SPECT myocardial perfusion studies require 10 to 15 minutes of acquisition time,
which reduces throughput and is often uncomfortable for patients.
Objective: To evaluate Astonish® resolution recovery software on full- and half-time gated myocardial
perfusion studies with and without attenuation correction. Direct comparisons were made with conventional
processing with filtered backprojection reconstruction.
Methods: 187 patients from 3 different centers had gated stress and rest myocardial perfusion studies.
Patients were administered 10 mCi for rest and 35 mCi for stress studies. Sixty-four projections were acquired
over the RAO-LPO arc for 20 to 30 seconds per view along with simultaneous Gd-153 transmission. Sixteen
frame samples of the R-R interval were used for the gating sequence. Each study was processed 5 different
ways: (1) Filtered backprojection of all 64 projections (full-time), (2) Astonish full-time, (3) Astonish 32
projections (half-time), (4) Astonish full-time with attenuation correction, (5) Astonish half-time with attenuation
correction. All short and long axis views were reviewed by 2 readers, with a third reader used to resolve
discordant cases. Image quality was judged with a 4-point scale, and studies were classified into 5 diagnostic
categories. Summed stress, rest ,and difference scores were generated for the standard 17-segment model.
Left ventricular function was evaluated using the Cedars Sinai QGS® package.
Results: Image quality was superior to filtered backprojection for both the Astonish processed stress and rest
perfusion image sets, but only the full-time Astonish gated images were judged to be superior to the
corresponding filtered backprojection gated images. The interpretive certainty ranged from 83% to 89% for the
3 methods. The diagnostic accuracy, as assessed by the catheterization results, was similar with sensitivity
ranging from 76% to 82% and specificity ranging from 62% to 75% . No statistical differences were found for
the perfusion defect severity and extent among the 3 methods. This was also the case for ventricular function.
Interpretive certainty decreased with attenuation correction, but normalcy and specificity were significantly
improved for both full- and half-time sets.
Conclusions: Astonish processing improves image quality compared to filtered backprojection without
compromising diagnostic accuracy. Attenuation correction provides additional improvement to specificity and
normalcy.
Reviewer's Comments: This paper is one of several recently published papers extolling the benefits of
resolution recovery software for shortening acquisition times in myocardial perfusion imaging. It seems likely
that these approaches will quickly move into mainstream use. (Reviewer-Mark T. Madsen, MD).
© 2009, Oakstone Medical Publishing
Keywords: SPECT Myocardial Perfusion, Acquisition Time
Print Tag: Refer to original journal article
PET Too Sensitive for Differentiating Obstructive CD
Prediction of the Need for Surgical Intervention in Obstructive Crohn’s Disease by 18F-FDG PET/CT.
Jacene HA, Ginsburg P, et al:
J Nucl Med 2009; 50 (November): 1751-1759
FDG PET/CT cannot differentiate patients with obstructive symptoms related to Crohn disease requiring
surgical resection for muscular hypertrophy/fibrosis from those with inflammation requiring medical
therapy.
Background: Crohn disease (CD) is a chronic, inflammatory process involving the small and large bowel.
Strictures often develop that lead to obstructive symptoms, sometimes requiring surgical resection. Active
inflammatory changes leading to strictures and obstructive changes can be treated medically, whereas bowel
obstruction due to the development of muscular hypertrophy and fibrosis requires surgical resection. If the
underlying cause of strictures can be determined preoperatively, surgery can be avoided in many patients.
FDG PET/CT is being evaluated as a noninvasive tool to differentiate inflammatory changes amenable to
medical treatment from hypertrophic/fibrotic changes requiring surgery.
Objective: To determine if FDG PET/CT can differentiate acute transmural inflammation from muscle
hypertrophy/fibrotic stenosis preoperatively in patients with CD.
Methods: 17 patients with proven CD were enrolled. However, only 13 of these 17 patients required surgery.
All were evaluated preoperatively with FDG PET/CT within 14 days of surgery. The CT portions of the PET/CT
were contrasted in 8 of 13 patients. Lesion intensity was semiquantitatively scored using the maximum
standard uptake value, and severity was scored on a 5-point scale (0 “definitely normal” to 5 “definitely
abnormal”). Histopathological analysis of surgery specimens was used as the gold standard by which imaging
was compared.
Results: Histopathology demonstrated predominant active inflammation in 5 patients, fibrosis in 4, and
hypertrophy in 3. One patient had no histopathology available because bypass was undertaken instead of
resection. Therefore, histopathology was positive for active inflammation in 5 patients and negative
(hypertrophy/fibrosis) in 7. PET/CT correctly identified active inflammation in 4 of 5 patients. The 7 patients
shown by histopathology to have hypertrophy/fibrosis were scored falsely by PET as active inflammation.
Histopathology did show some degree of acute and chronic inflammation in all resection specimens. IV
contrast did not significantly aid in the localization of bowel lesions on CT.
Conclusions: FDG PET/CT did not accurately differentiate a predominantly active inflammatory process from
muscular hypertrophy and fibrosis in patients with obstructive symptoms due to CD.
Reviewer's Comments: The premise of this study was interesting as the inflammatory nature of CD is the
perfect feature for PET/CT to exploit in differentiating active inflammation from fibrotic/hypertrophic changes.
The study shows, however, that even hypertrophic/fibrotic specimens demonstrate varying degrees of
inflammatory changes. As such, FDG-PET is not specific enough to exclude fibrosis/hypertrophy and,
therefore, cannot be used in this context to identify patients who can forego surgery. IV contrast CTs did not
significantly aid in the bowel localization of lesions. (Reviewer-Damita Thomas, MD).
© 2009, Oakstone Medical Publishing
Keywords: Crohn Disease, Inflammation, FDG PET/CT
Print Tag: Refer to original journal article
PET/CT Superior for Detecting Bone Mets in NSCLC
Detection of Bone Metastases in Patients With Lung Cancer: 99mTc-MDP Planar Bone Scintigraphy, 18F-Fluoride PET or
18F-FDG PET/CT.
Kruger S, Buck A, et al:
Eur J Nucl Med Mol Imaging 2009; 36 (November): 1807-1812
FDG-PET/CT is superior to bone scintigraphy in the detection of osteolytic bone metastases in non-small
cell lung cancer.
Background: The accurate staging of non-small cell lung cancer (NSCLC) patients is critical because it helps
define appropriate therapy. Bone scintigraphy (BS) has conventionally been used to separately stage the
skeleton, with F-18 making a comeback as a PET bone imaging agent. Although FDG-PET/CT is being
increasingly used as the initial staging modality in NSCLC, its use in skeletal staging is less well defined. As
FDG-PET/CT has the potential to be the “universal stager” of distant soft tissue and skeletal disease, it could
negate the need for separate skeletal staging.
Objective: To compare the efficacy of FDG-PET/CT to BS and F-18 fluoride PET (F-18) in detecting bone
metastases (BM) in NSCLC.
Methods: All patients underwent FDG-PET/CT, with 58 patients undergoing SPECT BS and 68 undergoing F18. All images were scored on a 5-point scale (1=“definite disease”; 5=“definitely no disease”). When all
imaging modalities were negative, the patient was defined as having no BM. BM was considered positive when
FDG-PET/CT and F-18 were positive. Equivocal findings were further evaluated (other imaging modalities).
Results: Osteolytic BM was diagnosed in 27% of patients. Of these, none were osteoblastic. FDG-PET/CT
and F-18 were concordant in 63 of 68 patients (no BM, n=50; BM, n=13), but disease was missed in 4 patients
by FDG and in 1 patient by F-18. FDG-PET and BS were concordant in 53 of 58 patients (no BM, n=42; BM,
n=11), but disease was missed by BS in 3 patients and scored as equivocal in the other 2. FDG detected
disease in the 3 patients missed by BS and scored the other 2 patients as negative.
Conclusions: FDG-PET/CT and F-18 are superior to BS in detecting bone metastases in NSCLC.
Reviewer's Comments: This interesting study attempts to compare BS, FDG-PET/CT, and F-18 PET. The
study is limited in that all patients did not undergo all imaging modalities; therefore FDG-PET/CT was not
directly compared to F-18. Also, the definition of “positivity” is based on 2 of 3 modalities under review (BM+
defined when positive on FDG-PET and F-18 but negative on BM). All BMs were osteolytic, which may
underestimate the accuracy of BS in detecting disease as BS is classically known to detect blastic disease
better than lytic disease. More studies directly comparing all 3 modalities in patients with both lytic and blastic
lesions are needed. (Reviewer-Damita Thomas, MD).
© 2009, Oakstone Medical Publishing
Keywords: Lung Cancer, Bone Metastases, Detection
Print Tag: Refer to original journal article
C-11 Choline Marker of Prostate Cancer Aggressiveness
Detection of Aggressive Primary Prostate Cancer With 11C-Choline PET/CT Using Multimodality Fusion Techniques.
Piert M, Park H, et al:
J Nucl Med 2009; 50 (October): 1585-1593
The tumor/background ratio on C-11 PET/CT correlates with prostate cancer aggressiveness in terms of
Gleason score and proliferative indices.
Background: There are no standardized criteria for determining the treatment strategy in men with newly
diagnosed prostate cancer. As such, these men undergo repeat biopsies to gauge progression of disease. This
is unsatisfactory for multiple reasons, including the sampling error associated with biopsy. Also, as some
disease is clinically irrelevant, some men undergo unnecessary procedures in an attempt to assess stage of
disease. A noninvasive tool would be helpful in determining which men should undergo more definitive
treatment. Prostate cancer is one of the malignancies that demonstrate increased choline kinase activity,
reflecting the tumor's need to synthesize phosphatidylcholine cellular membrane components. As such, C-11
PET/CT can identify increased uptake associated with this process and, thus, increased prostate tumor
activity.
Objective: To determine if C-11 PET/CT can identify high-risk prostate cancer.
Participants: 14 men with biopsy proven prostate cancer.
Methods: No patient had previous treatment or evidence of distant disease, as based on bone scans and CT.
All underwent C-11 PET/CT and MRI prior to prostatectomy. These images were fused with ex vivo MRI
images, as well as images of the whole mount pathology slice, in an attempt to localize the actual focus of
disease in the specimen to abnormalities seen on the PET/CT and MRI. Mean tumor SUV, maximum tumor
SUV, and mean tumor/background (T/B) ratios were obtained from the PET images. These were correlated
with the Gleason score and the proliferation indices MIB-1/Ki-67.
Results: The absolute SUV max/mean did not correlate with tumor aggressiveness as scored by the Gleason
score. However, the T/B SUV indices correlated with an increasing Gleason score, with the T/B ratio
differentiating high-grade disease from lower-grade disease. The T/B ratio also correlated with increasing
proliferative indices.
Conclusions: The T/B ratio on C-11 PET/CT correlates with prostate cancer aggressiveness in terms of
Gleason score and proliferative indices.
Reviewer's Comments: Although this is a study of a small number of men, it is quite interesting and well
executed. The authors sought to show how well C-11 PET/CT identifies prostate cancer and how well it
localizes the disease when compared to the actual pathology specimen. The investigators point out that the
clinical application of this approach is limited due to the time-consuming and likely costly nature of the image
fusions they performed. However, useful data can be gleaned from this study in that the T/B ratio in focal C-11
uptake was significantly associated with more aggressive cancers as defined by the Gleason score and by
proliferative indices. (Reviewer-Damita Thomas, MD).
© 2009, Oakstone Medical Publishing
Keywords: Prostate Cancer, Risk, C-11 PET/CT
Print Tag: Refer to original journal article
Good Correlation Between SPECT, cMRI for LV Volumes
Validation of 4D-MSPECT and QGS for Quantification of Left Ventricular Volumes and Ejection Fraction From Gated
99mTc-MIBI SPET: Comparison With Cardiac Magnetic Resonance Imaging.
Lipke CS, Kuhl HP, et al:
Eur J Nucl Med Mol Imaging 2004; 31 (April): 482-490
SPECT imaging and quantitation with 4D-MSPECT or QGS shows good correlation with cardiac MRI for
determining left ventricular volumes.
Background: The popular software packages 4D-MSPECT© and Quantitative Gated SPECT (QGS) are used
for viewing myocardial perfusion images and provide estimates of the left ventricular (LV) end systolic volumes
(ESV) and end diastolic volumes (EDV). These volumes in conjunction with LV ejection fraction (LVEF) enable
us to estimate the stroke volume.
Objective: To assess the accuracy of LV ESV and EDV as determined by 4D-MSPECT and QGS using
cardiac MRI (cMRI) as a reference standard.
Methods: 54 patients with known or suspected coronary artery disease underwent routine gated SPECT
myocardial perfusion imaging using 99mTc-MIBI. SPECT images were quantitatively analyzed using 2 different
software packages: 4D-MSPECT and QGS. Automatic processing was used with each software package.
Each patient underwent cMRI directly before or after SPECT imaging. Data from cMRI were analyzed using
commercially available MASS software. To calculate LV volumes, observers manually delineated the
endomyocardial border.
Results: There was good correlation for measurement of EDV as determined by cMRI versus SPECT using
4D-MSPECT (R=0.89) or QGS (R=0.92). Similarly, there was good correlation for measuring ESV using cMRI
versus SPECT (R=0.96 for both 4D-MSPECT and QGS). Both 4D-MSPECT and QGS consistently
underestimated EDV in comparison with cMRI. There was no significant difference in ESV estimates using
SPECT or cMRI. QGS tended to underestimate LVEF more than 4D-MSPECT, with the magnitude of the
underestimation largest for good ejection fractions. Correlation between 4D-MSPECT and QGS was very high
(R=0.96, slopes of regression lines close to 1).
Conclusions: Automatic processing of SPECT myocardial perfusion images with 4D-MSPECT or QGS
provides reasonably reliable estimates for LV ESV and EDV as compared with cMRI.
Reviewer's Comments: High cardiac output states can sometimes be identified using 4D-MSPECT or QGS.
Recently, we performed a myocardial perfusion study on an inpatient with clinical evidence for heart failure. His
perfusion study was normal except for an abnormally high cardiac output, which turned out to be related to
sepsis. (Reviewer-Shayne Squires, MD).
© 2009, Oakstone Medical Publishing
Keywords: Ventricular Volume, SPECT, Myocardial Perfusion Imaging
Print Tag: Refer to original journal article
FDG-PET Does Not Exclude RCC Distant Metastases
F-18 Fluorodeoxyglucose Positron Emission Tomography in the Evaluation of Distant Metastases From Renal Cell
Carcinoma.
Majhail NS, Urbain JL, et al:
J Clin Oncol 2003; 21 (November 1): 3995-4000
FDG-PET cannot reliably exclude distant metastases in renal cell carcinoma. In this study, FDG-PET did
not detect any lesions that were not also seen by CT or MRI.
Objective: To determine the sensitivity, specificity, and accuracy of FDG-PET for the detection of distant
metastases in patients with primary renal cell carcinoma (RCC).
Participants: 24 patients with histologically proven RCC (clear-cell carcinoma, n=24).
Methods: Each patient had undergone prior nephrectomy or partial nephrectomy and was referred for
evaluation of possible distant metastases. Each patient underwent anatomic imaging with CT or MRI and FDGPET within a median of 10.5 days. Surgery or biopsy of suspected lesions was performed a median of 27.5
days after PET.
Results: Among the 24 patients, a total of 36 suspected lesions were detected by anatomic imaging, of which
33 were positive for malignancy on histologic examination. Most of the metastases were seen in the lungs or
mediastinum, but some occurred in the brain, chest wall, retroperitoneum, bone, and adrenal gland. The
sensitivity, specificity, and positive predictive value of PET were 63.6%, 100%, and 100%, respectively. The
negative predictive value was 20%. FDG-PET did not detect any lesions that were not also seen by CT or MRI.
The mean size of lesions detected by PET was 2.2 cm, whereas the mean size of lesions missed by PET was
1.0 cm.
Conclusions: FDG-PET is insufficiently sensitive to exclude distant metastases in patients with RCC. It does,
however, have good specificity.
Reviewer's Comments: In cases where lesions detected by CT or MRI are sufficiently large and biopsy is
potentially difficult, FDG-PET may play a useful role in assessing whether the lesions are metastatic.
(Reviewer-Shayne Squires, MD).
© 2009, Oakstone Medical Publishing
Keywords: Renal Cell Carcinoma, Metastases, FDG-PET
Print Tag: Refer to original journal article
Thyroid Stunning Mediated by NIS Down-Regulation
Down-Regulation of the Sodium/Iodide Symporter Explains 131I-Induced Thyroid Stunning.
Norden MM, Larsson F, et al:
Cancer Res 2007; 67 (August 1): 7512-7517
Thyroid “stunning” due to low-level 131-iodine exposure is mediated by decreased transcription of the
sodium/iodide symporter (NIS) gene. TSH and insulin-like growth factor accelerate NIS expression.
Background: Exposure of the thyroid gland to small, diagnostic doses of 131-I can result in subsequently
reduced uptake of therapeutic doses of 131-I in a phenomenon known as “thyroid stunning.”
Objective: To test the hypothesis that thyroid stunning is mediated by a reduction in transcription of the
sodium/iodide symporter gene (NIS).
Methods: This study was performed in vitro. Porcine thyroid epithelial cells were cultured as a monolayer and
incubated with TSH, insulin-like growth factor 1 (IGF-1), or both throughout the experiment. Cells were
incubated with 131-I for 48 hours to achieve a mean absorbed dose of 7.5 Gy. Methimazole was added to
prevent incorporation of radioiodine into protein. Transepithelial transport of 125-I was measured at 2, 5, and 7
days after the start of irradiation with 131-I. Real-time polymerase chain reaction (RT-PCR) was used to
quantify NIS mRNA expression at 2, 5, and 7 days after initiating exposure to 131-I.
Results: In cultures stimulated with TSH, exposure to 131-I resulted in a 60%average decrease in NIS mRNA
expression, which was accompanied by a decrease in transport of 125-I. Exposure of thymocytes to IGF-1 is
known to stimulate NIS expression similarly to TSH, but in this study, irradiation with 131-I also reduced NIS
expression in response to IGF-1. Incubation of cells with TSH and IGF-1 together resulted in 3-fold higher
expression of NIS compared to incubation with TSH alone. Irradiation of cells incubated with both TSH and
IGF-1 caused a reduction in NIS expression, but the NIS expression level was higher than in non-irradiated
cells stimulated with TSH alone.
Conclusions: Thyroid stunning in response to low doses of 131-I is likely mediated by down-regulation of NIS
expression at the transcriptional level.
Reviewer's Comments: If co-administration of TSH and IGF-1 synergistically increases NIS expression in
humans the same as it does in pigs, we can probably expect recombinant IGF-1 administration along with
rTSH and radioiodine therapy in thyroid cancer patients at some point in the future. (Reviewer-Shayne Squires,
MD).
© 2009, Oakstone Medical Publishing
Keywords: Thyroid Stunning, 131-I, IGF-1
Print Tag: Refer to original journal article
BMIPP Predictive of Cardiovascular Risk for CAD
Prognostic Value of Myocardial Metabolic Imaging With BMIPP in the Spectrum of Coronary Artery Disease: A Systematic
Review.
Inaba Y, Bergmann SR:
J Nucl Cardiol 2009; October 23 (): epub ahead of print
BMIPP fatty acid imaging of the heart is useful for risk stratifying patients with coronary artery disease,
especially those with acute chest pain.
Background: β-methyl-p-[123I]-iodophenyl-pentadecanoic acid (BMIPP) is a radioisotope used for fatty acid
imaging. Although not yet approved for use in the United States, it has been used extensively in Japan for
several years (>500,000 patients for >10 years). The Japanese Circulation Society stated in 2005 that BMIPP
imaging was useful to detect myocardial ischemia (MI) in patients presenting with acute chest pain (level of
evidence: B).
Objective: To determine the clinical utility of BMIPP imaging in coronary artery disease (CAD).
Design: Meta-analysis of 11 studies that included a total of 1315 participants. The mean patient age was 63
years, and the mean follow-up was 33 months.
Methods: BMIPP imaging was conducted at rest in all patients, with some studies also including a rest Tl-201
scan.
Results: In patients with suspected acute coronary syndrome, a perfusion defect on BMIPP imaging
(suggesting an abnormal switch from fatty acid to glucose metabolism by the myocardium) was significantly
associated with future hard events (cardiac death, nonfatal MI). In these patients with suspected acute
coronary syndrome, a normal BMIPP scan had a negative predictive value for future hard cardiac events of
98.9% during a 3.5-year follow-up. In patients with an acute MI, a larger defect on BMIPP imaging was
associated with an increased risk of future adverse cardiac events. In patients with a mismatch on BMIPP/Tl201 imaging several months after coronary revascularization, there was an increased risk of future adverse
cardiac events.
Conclusions: BMIPP imaging is useful in the identification of patients with acute coronary syndrome, in the
risk assessment of patients with acute MI, in the identification of appropriate patients for coronary
revascularization, and in the follow-up of patients after revascularization.
Reviewer's Comments: This paper highlights the burdens of the excessive bureaucracy facing nuclear
medicine physicians in the U.S. BMIPP still remains unapproved for use in the U.S., although it has been
safely used for >10 years and in >500,000 patients in Japan. BMIPP/Tl-201 appears to give comparable
results to stress myocardial perfusion imaging, but may be safer (especially in patients with acute chest pain)
since both the BMIPP and Tl-201 image sets are acquired at rest and the patient does not undergo cardiac
stress testing. The conversion from fatty acid to glucose metabolism by the heart can persist for days after an
ischemic insult or be persistent in the case of hibernating myocardium, thus BMIPP scanning has also been
called “ischemic memory imaging.” (Reviewer-Thomas F. Heston, MD).
© 2009, Oakstone Medical Publishing
Keywords: Coronary Artery Disease, BMIPP, Prognosis
Print Tag: Refer to original journal article
Substantial Variability in Image Reconstruction Software
A Multi-Center Phantom Study Comparing Image Resolution From Three State-of-the-Art SPECT-CT Systems.
Hughes T, Shcherbinin S, Celler A:
J Nucl Cardiol 2009; 16 (November-December): 914-926
Using a standardized reconstruction algorithm, 3 different SPECT/CT cameras had comparable image
resolution. But, resolution varied substantially when using the reconstruction software provided by various
manufacturers.
Background: SPECT/CT camera systems have the potential for improving image quality through several
resolution recovery methods. Techniques that attempt to improve scan quality include attenuation correction,
iterative reconstruction utilizing resolution recovery, and scatter correction.
Objective: To evaluate the relative performance of 3 leading state-of-the-art SPECT/CT systems: Philips’
Precedence, GE’s Infinia Hawkeye, and Siemens' Symbia-T6. In addition, to evaluate the performance of each
system's imaging processing software: Astonish (Philips), Evolution (GE), and Flash-3D (Siemens).
Design: Phantom study.
Methods: A thorax phantom with an insert modeling a healthy heart was scanned on each camera system.
Images were processed using the researchers’ own software in addition to the camera’s included proprietary
software (listed above). The myocardial wall thickness was calculated for each camera system after processing
by the proprietary software and after processing by the researchers’ software.
Results: Using a 50% threshold, the myocardial wall thickness measured by the SPECT/CT systems utilizing
the researcher’s reconstruction algorithm ranged from 7.7 mm to 9.3 mm. The differences found between
camera systems were statistically insignificant. However, when reconstruction was performed using each
system's proprietary software, using a threshold of 50%, the myocardial wall thickness varied widely: 9.3 mm
(Philips’ Astonish), 19.2 mm (GE’s Evolution), and 18.4 mm (Siemens’ Flash-3D). Utilizing NEMA-type
experiments with capillary tubes, the tomographic resolution for each camera system, using each system's
proprietary reconstruction software, ranged from 8.0 mm to 8.3 mm (nonsignificant differences found between
manufacturers). Using an optimized threshold for each camera system and a 128 x 128 matrix size, there were
no significant differences found in myocardial wall thickness measured by each system using the system’s
proprietary software.
Conclusions: The raw data acquired by the 3 major state-of-the-art SPECT/CT systems are similar in quality,
with no significant differences found in phantom imaging or capillary tube imaging. Reconstruction algorithms
native to each of the SPECT/CT systems, however, show significant differences when a standardized
threshold is utilized.
Reviewer's Comments: This paper discusses the various reconstruction algorithms and methods used to
increase image quality. The raw data acquired by each of the major SPECT/CT systems are basically
equivalent in quality. However, care must be taken when processing the data. When a standardized threshold
of 50% is used during image reconstruction, the results will vary widely from system to system. When a
system-specific optimized threshold is used during reconstruction, scan quality appears to be uniform between
each of the various SPECT/CT systems. (Reviewer-Thomas F. Heston, MD).
© 2009, Oakstone Medical Publishing
Keywords: Myocardial Perfusion Imaging, SPECT, Image Quality
Print Tag: Refer to original journal article
Cancer Risk High in Incidental Focal Thyroid FDG Uptake
The Significance and Management of Incidental [18F]Fluorodeoxyglucose-Positron-Emission Tomography Uptake in the
Thyroid Gland in Patients With Cancer.
Eloy JA, Brett EM, et al:
AJNR Am J Neuroradiol 2009; 30 (August): 1431-1434
The risk of thyroid malignancy in focal thyroid FDG uptake may be as high as 28%. Further evaluation
with cytology is warranted in these cases to exclude cancer.
Background: Incidental foci of radiotracer uptake in the thyroid are seen in 1% to 5% of FDG-PET studies and
are associated with a significant risk of malignancy.
Objective: To determine the clinical significance of incidentally discovered focal thyroid FDG uptake in
patients referred for PET imaging of nonthyroidal cancer.
Methods: This retrospective study included patients referred for workup of nonthyroidal cancer with FDG-PET.
Patients were included if they had focal radiotracer uptake (defined as increased uptake in <1 lobe of the
thyroid gland) and complete follow-up records. Patients with diffusely increased FDG uptake throughout the
thyroid gland were excluded from follow-up. Of the 630 patients referred between March 2004 and June 2006,
18 met inclusion criteria. Eleven of these were undergoing PET for staging of lymphoma. The remaining
patients were being evaluated for various other nonthyroidal cancers.
Results: The prevalence of incidental focal thyroid uptake in this study was 4.8%. All 18 patients with follow-up
underwent eventual thyroidectomy. Five of the 18 had papillary thyroid carcinoma, and the remaining patients
had no thyroid malignancy. The mean SUVmax was 2.9 (1.1-6.8) in patients without thyroid malignancy and was
3.4 (1.1-7.4) in patients with papillary thyroid cancer (P=0.63).
Conclusions: Patients with incidentally discovered hypermetabolic thyroid nodules have a significant risk of
thyroid cancer. Further evaluation with cytology is warranted. Many of these patients will likely go on to have
thyroidectomy.
Reviewer's Comments: The results of this study do not apply when the thyroid uptake is diffuse. Generally,
diffuse uptake is attributed to benign variant, Graves disease, or thyroiditis. (Reviewer-Shayne Squires, MD).
© 2009, Oakstone Medical Publishing
Keywords: Thyroid Cancer, FDG-PET, Incidental Findings
Print Tag: Refer to original journal article
Physiology Superior to Anatomy in IHD Stratification
Physiologic Risk Assessment in Stable Ischemic Heart Disease: Still Superior to the Anatomic Angiographic Approach.
Gimelli A, Marzullo P, Rovai D:
J Nucl Cardiol 2009; 16 (September-October): 697-700
In patients with stable ischemic heart disease, physiologic risk assessment is the best predictor of cardiac
event-free survival.
Background: A recent survey of the European Society of Cardiology found that noninvasive tests are
underutilized, resulting in an excessive number of patients without significant ischemic heart disease (IHD)
undergoing invasive coronary angiography. In addition, coronary lesions detected by coronary angiography
frequently undergo revascularization, even without evidence that myocardial blood supply or mechanical
function is altered.
Objective: To compare the relative prognostic power of gated SPECT imaging versus anatomic imaging.
Design: Editorial review. Functional vs Invasive Assessment: In patients with known coronary artery
disease, exercise variables are known to provide incremental prognostic information over coronary anatomy.
As early as 1992, using Tl-201 planar imaging, researchers found that myocardial perfusion was superior to
coronary angiography in the risk stratification of patients with IHD. Part of the reason for this is the fact that
invasive coronary angiography gives no information on microvascular dysfunction, which is increasingly
recognized as an independent determinant of disease progression and adverse prognosis. Functional vs
Noninvasive Angiography: Imaging approaches that combine quantitative information about the anatomic
burden of IHD with its physiologic consequences appear to offer improved risk stratification in IHD. Specifically,
coronary artery calcium scores help risk stratify patients both with and without ischemia on perfusion imaging.
However, an independent and incremental prognostic value of CT angiography over clinical and scintigraphic
variables has not yet been shown. Current trials looking at this issue are the EVINCI study in Europe and the
SPARC trial in the United States. Myocardial Perfusion Imaging and Revascularization: Gated SPECT
imaging appears to be beneficial in identifying patients who will benefit from coronary revascularization based
on the COURAGE Trial data. Proper Diagnostic Workup: Myocardial perfusion imaging at rest and poststress is still the best predictor of cardiac event-free survival, even compared with an extensive workup. Gated
SPECT carries prognostic information greater than that provided by angiography. The authors recommend
that, prior to coronary angiography, left ventricular function and myocardial perfusion should be known.
Conclusions: In patients with stable IHD, a physiologic risk assessment is superior to an angiographic
approach.
Reviewer's Comments: Despite advances in CT technology, human physiologic principles have not changed.
For almost 2 decades, it has been consistently shown that physiology is superior to anatomy in the prognostic
stratification of patients with IHD. This is a good review of the topic. Figure 1 in the manuscript would be
particularly useful in educating referring clinicians. (Reviewer-Thomas F. Heston, MD).
© 2009, Oakstone Medical Publishing
Keywords: Ischemic Heart Disease, Diagnosis, Prognosis
Print Tag: Refer to original journal article