Download Whole-body magnetic resonance imaging (WB

Whole-body magnetic resonance imaging (WB-MRI)
including diffusion-weighted imaging with background
signal suppression (DWIBS) vs 18F-FDG-PET/CT in the
study of malignant tumours
Poster No.:
C-1918
Congress:
ECR 2013
Type:
Scientific Exhibit
Authors:
F. Padovano, L. Calandriello, F. Maggi, A. Botto, A. R. Larici, L.
Bonomo; Rome/IT
Keywords:
Oncology, Nuclear medicine, MR, PET-CT, Comparative studies,
Neoplasia
DOI:
10.1594/ecr2013/C-1918
Any information contained in this pdf file is automatically generated from digital material
submitted to EPOS by third parties in the form of scientific presentations. References
to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in
any way constitute or imply ECR's endorsement, sponsorship or recommendation of the
third party, information, product or service. ECR is not responsible for the content of
these pages and does not make any representations regarding the content or accuracy
of material in this file.
As per copyright regulations, any unauthorised use of the material or parts thereof as
well as commercial reproduction or multiple distribution by any traditional or electronically
based reproduction/publication method ist strictly prohibited.
You agree to defend, indemnify, and hold ECR harmless from and against any and all
claims, damages, costs, and expenses, including attorneys' fees, arising from or related
to your use of these pages.
Please note: Links to movies, ppt slideshows and any other multimedia files are not
available in the pdf version of presentations.
www.myESR.org
Page 1 of 11
Purpose
When patients are diagnosed with a malignant tumor an accurate staging is essential
to assess prognosis and to decide the most appropriate therapeutic option. Imaging
plays a key role in tumor staging and generally allows an evaluation of the primary
tumor site, as well as the most likely sites for distant metastases (1). Multi-detector
18
computed tomography (MDCT) and, recently, F-fluorodeoxyglucose positron emission
tomography/computed tomography (FDG-PET/CT) are widely used in order to get an
integrated diagnostic approach to cancer as a systemic disease. There are, however,
some shortcomings to these techniques, amongst which are patient's exposure to
ionising radiation and some limitations in spatial and contrast resolution; false positive
and false negative results of FDG-PET are well known, too (2).
Magnetic resonance imaging (MRI) with its lack of ionizing radiation, high soft tissue
contrast and good spatial resolution is a useful application for tumor detection and staging
of malignancies and
could overcome the limits of FDG-PET/CT (2).
In recent years, significant improvements in hardware and important innovations in
sequence design and image acquisition have allowed a whole-body imaging with MRI
(WB-MRI) in a suitable acquisition time without impairment of spatial resolution (3).
Furthermore, the introduction of diffusion weighted MRI (DWI) has increased the potential
for the detection of malignancies throughout the body. Diffusion weighted MRI is based
on the assessment of the random water proton movement within tissues and reflects
cellular density and tissue architecture, providing a functional imaging techniques that
does not require the use of ionising radiation or MR contrast agents and can easily be
implemented into a standard MRI protocol (1). In 2004, Takahara et al. introduced an
interesting new concept of DWI, called DWIBS (diffusion-weighted whole-body imaging
with background body signal suppression), which made it possible to obtain high quality
diffusion images of the whole-body during free breathing (4).
Whole body MRI (WB-MRI) has then emerged as an excellent candidate for the
assessment of patients with neoplastic disease and many authors have compared FDGPET/CT and WB-MRI in oncology (5). Moreover the addition of DWI sequences to
WBMRI has been showed to improve the sensibility and the diagnostic accuracy of
WBMRI in the assessment of oncologic patients (6).
The purpose of this study was to compare diagnostic accuracy of WBMRI, with diffusion
sequences (DWIBS), and FDG-PET/CT, which is considered the standard of reference
among whole-body imaging modalities, in Patients with malignant tumors.
Page 2 of 11
Methods and Materials
Twenty Patients (14 males, 6 females, mean age 69 years) with histologically proven
malignancies were routinely staged with FDG-PET/CT and underwent WBMRI within
fifteen days. Study population included 9 Patients with lung cancer, 8 with gastrointestinal
cancer (5 colorectal cancers, 3 gastric cancers), 3 with bone tumors (1 ewing sarcoma,
2 osteosarcoma). In 6 Patients exams were performed for primary staging. Four Patients
underwent chemotherapy, 6 Patients underwent combined chemo- and radio-therapy
and 4 Patients underwent surgical resection of the primary malignancy before imaging
protocol respectively.
FDG-PET/CT exams were performed on an integrated PET/CT system with 16 or 2 slice
18
CT (GEMINI Dual and GXL, PHILIPS Medical Systems). F-FDG was administered in a
standard dose of 37MBq/10Kg, 60 min before scan, after a fasting period of minimum 6
hours. All patients received unenhanced low dose CT for attenuation correction.
MRI exams were performed on a 1.5 T scanner (Achieva, Philips Medical Systems, Best,
Netherlands, Release 2.6, Level 3). A q-body coil was used, with the patient positioned
feet first on an extended anatomical coverage table, based on rolling-table technology
(MobiTrak, Philips). The used sequences were: T1-weighted Turbo Spin Echo (TSE) and
T2-weighted Short Tau Inversion Recovery (STIR) in coronal orientation to encompass
all anatomical districts from the head to at least the distal thigh; T1-weighted TSE and T2weighted STIR in sagittal orientation to encompass the spine; DWIBS (single-shot echoplanar imaging (ss-EPI) with STIR fat suppression, b values = 0 and 1000 s/mm2) in
transverse orientation. Total examination time was 50 min. All data were acquired during
free breathing. No contrast agent was applied.
All images were reviewed performing a qualitative analysis only, in double-blind manner.
MRI images were reviewed by two radiologists in consensus and DWIBS images were
reviewed with inverted gray scale. PET-CT images were analyzed by one radiologist and
one nuclear physician in consensus. Each lesion detected with PET-CT and WBMRI
was recorded. The findings detected on WBMRI an PET-CT were compared on a perlesion basis using pathologic examination, if available, or imaging follow-up as standard
of reference.
Overall accuracy was calculated for lesion detection for both techniques. Sensitivity,
specificity, positive predictive value (PPV) and negative predictive value (NPV) were
calculated for both WBMRI and PET-CT. Statistical significance of the differences
between the results obtained by PET/CT and MRI was tested using McNemar's test. A p
value of less than 0.05 was considered statistically significant.
Page 3 of 11
Results
Whole-body MRI as well as FDG-PET/CT provided diagnostic image quality in all cases
(Fig. 1, 2).
WBMRI detected 74 lesions with 18 bone lesions, 12 malignant lymph nodes, 12 lung
lesions, 20 liver lesions and 12 "other" lesions including 2 adrenal gland lesions, 2 soft
tissue lesions, 3 gastrointestinal tract lesions and 5 peritoneal implants. FDG-PET/CT
detected 70 lesions with 16 bone lesions, 10 malignant lymph nodes, 14 lung lesions, 20
liver lesions and 10 "other" lesions including 2 adrenal gland lesions, 2 soft tissue lesions,
3 gastrointestinal tract lesions and 3 peritoneal implants.
WBMRI provided 2 false positive lesions both of them represented by lymph nodes who
revealed to be inflammatory nodes (Fig. 3), and one false negative lesion represented
by a lung nodule with maximum diameter of 7 mm (Fig. 4). FDG-PET/CT provided one
false positive lesion represented by a bone lesion related to recent sternotomy and 3
false negative lesions including one peritoneal implants and 2 bone lesions (Fig. 5, 6).
Sensitivity, specificity, PPV and NPV were respectively 98,6%, 83,3%, 97,3%, 90,9% for
WBMRI and 95,8%, 90,9%, 98,6% and 76,9% for FDG-PET/CT. Diagnostic accuracy
was 96,4% for WBMRI and 95,1% for FDG-PET/CT.
Comparison of methods by McNemar's test revealed no statistically significant difference
between WBMRI and FDG-PET/CT (Fig.5).
Images for this section:
Page 4 of 11
Fig. 1: Fig. 1 - 49 years old Patient with right middle lobe adenocarcinoma. The lesion
is easily identified on coronal T1 TSE (A) and T2 STIR (B) images. The lesion shows
high signal intensity on axial DWI (b value: 1000s/mm2) image (C) and 18F-FDG uptake
on PET-CT image (D)
Page 5 of 11
Fig. 2: Fig. 2 - 65 years old Patient with lung adenocarcinoma. Primary lung tumor in
the right upper lobe (upper row - long arrows) clearly identified on coronal T2 STIR and
T1 TSE images (A, B), on axial DWI (b value: 1000s/mm2) image (C) and on PET/CT
image (D). Contralateral metastatic lung nodule (middle row - short arrows) also evident
on T2 STIR and T1 TSE coronal images (E, F), on axial DWI (b value: 1000s/mm2)
image (G) and on PET/CT image (H). Hilar bilateral lymph nodes metastases (lower row
- arrowheads) identified on T2 STIR and T1 TSE coronal images (I, L), on axial DWI (b
value: 1000s/mm2) image (M) and on PET/CT image (N)
Page 6 of 11
Fig. 3: Fig. 3 - 50 years old man with left upper lobe squamous cell carcinoma. Coronal
T2 STIR and T1 TSE images (A, B) show a lateral cervical lymph node with high signal
intensity on axial DWI (b value: 1000s/mm2) image (C). No 18F-FDG uptake is showed
on PET-CT image (D). The lesion was considered suspect for metastasis on WBMRI.
The lymph node revealed to be an inflammatory node
Page 7 of 11
Fig. 4: Fig. 4 - 63 years old Patient with colorectal cancer. PET-CT image shows 18FFDG uptake of two lung metastases measuring 11 and 7 mm respectively (A). On axial
DWI (b value: 1000s/mm2) image (B) the smaller lesion is not evident while the bigger
one is characterized by restricted diffusion. The smaller lesion is not visualized also on
T1 TSE coronal image (C)
Fig. 5: Fig. 5 - 59 years old Patient with colorectal cancer. Bone metastasis involving
the proximal metaphysis and neck of the right femur (arrows). The lesion appears
hyperintense on coronal T2 STIR image (A), hypointense in coronal T1 TSE image (B)
and shows high signal intensity on axial DWI (b value: 1000s/mm2) image (C). The PETCT image (D) shows evident 18F-FDG uptake
Page 8 of 11
Fig. 6: Fig. 6 - Same Patient than Figure 5. Bone metastasis on the right ischial ramus
(arrows). The lesion appears hypointense on coronal T1 TSE image (A), hyperintense on
coronal T2 STIR image (B) and shows high signal intensity on axial DWI (b value: 1000s/
mm2) image (C). The lesion was not evident on PET-CT image (D)
Page 9 of 11
Conclusion
WBMRI seems to be a valid alternative method compared to PET/CT in oncology showing
good results in terms of sensitivity and specificity for the detection of malignant lesions.
Concerning FDG-PET/CT, we found a higher accuracy in the assessment of lymph node
lesions in accordance with other studies (5,7). This might be due to the generally high
signal of lymph nodes in DWI and the lack of standardisation in lymph nodes interpretation
using DWI (8) .
As for WBMRI, in particular thanks to the use of DWI, seems to show an higher accuracy,
compared to PET/CT, in the evaluation of bone lesions, in accordance with a previous
study by Takenaka et al (6) while it seems to have some limitations in the assessment of
small lung nodules, another already known limit of WBMRI (7, 9).
The main limit of our study is represented by the small number of patients included and
further larger prospective studies comparing these two whole-body imaging techniques
are needed to better assess the role of WB-MRI compared to FDG-PET/CT in oncologic
Patients and in specific tumor types. Another limit was represented by the qualitative
analysis performed to assess DWIBS images; in fact the quantitative analysis with ADC
assessment could help in discriminating malignant from non-malignant lesions (8).
References
1.
2.
3.
4.
5.
Lambregts DMJ, Maas M, Cappendijk VC, et al. Whole-body diffusionweighted magnetic resonance imaging: Current evidence in oncology and
potential role in colorectal cancer staging. European Journal of Cancer
2011; 47: 2107-2116
Ciliberto M, Maggi F, Treglia G, et al. Comparison between whole-body
MRI and Fluorine-18-Fluorodeoxyglucose PET or PET/CT in oncology: a
systematic review. Radiol Oncol 2013; in press
Schmidt GP, Reiser MF, Baur-Melnyk A. Whole-body MRI for the staging
and follow-up of Patients with metastasis. European Journal of Radiology
2009; 70: 393-400
Takahara T, Imai Y, Yamashita T, et al. Diffusion weighted whole body
imaging with background body signal suppression (DWIBS): technical
improvement using free breathing, STIR and high resolution 3D display.
Radiat Med 2004; 22: 275-282
Fischer MA, Nanz D, Hany T, et al. Diagnostic accuracy of whole-body MRI/
DWI image fusion for detection of malignant tumours: a comparison with
PET/CT. Eur Radio 2011; 21: 246-255
Page 10 of 11
6.
7.
8.
9.
Takenaka D, Ohno Y, Matsumoto K, et al. Detection of bone metastases in
Non-Small cell lung cancer Patients: comparison of whole-body diffusionweighted imaging (DWI), whole-body MR imaging without and with DWI,
whole-body FDG-PET/CT, and bone scintigraphy. Journal of magnetic
resonance imaging 2009; 30: 298-308
Yi CA, Shin KM, Lee KS, et al. Non-small cell lung cancer staging: efficacy
comparison of integrated PET/CT versus 3.0-T whole-body MR imging.
Radiology 2008; 248:632-642
Kwee TC, Takahara T, Ochiai R, et al. Diffusion-weighted whole-body
imaging with background body signal suppression (DWIBS): features and
potential applications in oncology. Eur Radiol 2008; 18: 1937-1952
Chen W, Jian W, Li H, et al. Whole-body diffusion-weighted imaging vs.
FDG-PET for the detection of non-small-cell lung cancer. How do they
measure up? Magnetic resonance imaging 2010; 28: 613-620
Personal Information
Page 11 of 11