Download Diffusion Weighted Imaging Findings on Biopsy Proven Breast

Diffusion weighted imaging findings on biopsy proven breast cancers which demonstrate
enhancement kinetics with indeterminate time-signal activity curves.
Rachelle Cruz Centeno, DO PGY4
Midwestern University, Chicago College of Osteopathic Medicine
Introduction
Results/Statistics
Imaging
MR diffusion weighted imaging (DWI) is based on the uninhibited
movement of water molecules within normal tissue called
Brownian motion (6). DWI is most commonly used in the study of
brain infarction. Restriction of water molecules occurs within
minutes after an acute ischemic event and is likely related to
cytotoxic edema. Brownian motion is also observed in areas of
dense tissue cellularity; this is seen in various types of tumors,
most commonly within the brain (3). Ongoing studies are also
being performed on the use of extra cranial DWI to evaluate body
tumors, including those tumors found within the breast (5) .
Contrast enhanced breast MR has been revolutionary in the
evaluation of breast cancer. However, this modality can be limited
when enhancing breast lesions demonstrate indeterminate (Type
II) time-signal activity
curves (TAC/kinetics). DWI has
demonstrated a high sensitivity in the detection of tumors (5).
Therefore, correlating restricted diffusion within breast lesions that
demonstrate indeterminate TAC may aid in interpretation of breast
imaging studies.
Of the 44 breast MR’s that were evaluated, 4 were excluded
secondary to poor quality of DWI and post contrast images obtained.
TABLE 1: Restricted diffusion correlate with enhancement and TAC’s
Total n= 40
Enhancement with
TAC suspicious for
malignancy
Enhancement with
indeterminate TAC
IRB approval was obtained before the initiation of this study. A
prospective, preliminary study was performed on the 44 breast
MRI’s performed in an 11 month period at the Patricia A. Joyce
Comprehensive Cancer Institute, St. James Hospital. Female
patients ranged in age, from 38 to 86, and each had a biopsy
proven breast malignancy. No restrictions were made on the type
of malignancy and patients were at various stages of disease at the
time of MRI evaluation. All studies were performed on a GE 1.5
Tesla MR scanner. A standard MR breast protocol with pre and
post contrast imaging using Gadolinium was followed (Sagittal FSE
T2, Axial T1 and T2, and Axial Vibrant). DWI using a b value of
1000 was added to this standard protocol. Time activity curves
were obtained using Dynacad system. Biopsy proven malignant
lesions were evaluated for restricted diffusion and these findings
were compared with post contrast images and associated timesignal activity curves. Lesions were determined positive or
negative based on diffusion-weighted images findings.
After prospective analysis of 40 breast MRI’s, 12
patients
with breast lesions demonstrating
indeterminate Type II TAC’s, showed positive restricted
diffusion in the area of known malignancy . These
results suggest persistent disease, despite having
indeterminate kinetics. However, the sensitivity and
specificity of these results were low, measuring 60%
and 70%, respectively.
18 patients demonstrated breast lesions with positive restricted
diffusion and corresponding enhancement and TAC’s suggestive of
malignancy. 3 patients demonstrated breast lesions with negative
restricted diffusion but maintained enhancement with TAC’s
suggestive of malignancy. 12 patients demonstrated breast lesions
with positive restricted diffusion and enhancement with indeterminate
TAC’s. 7 patients demonstrated breast lesions with negative restricted
diffusion and indeterminate TAC’s.
MR Results
Methods
Conclusion
Positive Restricted
Diffusion
18
Negative Restricted
Diffusion
3
12
7
Figure 1: Diffusion weighted
axial image of breasts
demonstrating a focus of
restricted diffusion within the
upper outer left breast
corresponding to area of
enhancement
on
post
contrast image.
18 patients with breast lesions with malignant Type III
TAC’s demonstrated positive restricted diffusion,
suggesting persistent disease. 3 patients with breast
lesions of malignant Type III curves demonstrated
negative restricted diffusion. Upon further review of
these 3 cases, the lesions were found to be less than
1cm; this finding may be a contributing factor to the
negative DWI study (4) .
Figure 2: Post contrast axial
image
of
breasts
demonstrating
area
of
enhancement within the
upper outer left breast
corresponding to focus of
restricted diffusion.
Lastly, 7 patients demonstrated breast lesions with
indeterminate Type II kinetics and negative restricted
diffusion, suggesting no persistent disease. However, it
was noted that several of these cases also
demonstrated a lesion size of less than 1 cm; this also
may have contributed to the negative outcome DWI
study (4).
Prior research has proven the accuracy of DWI in breast
MRI using a large, controlled population (5,6). Despite
the low sensitivity and specificity in this particular study,
there is evidence in these results to suggest the benefit
of DWI in breast MR. Further research would require a
larger, controlled patient population, as well as the
inclusion of specific diffusion-weighted parameters with
ADC mapping in order to confirm the use of DWI in the
standard breast MRI protocol at our institution.
Lesions with Positive Restricted Diffusion and Enhancement and
Indeterminate TAC’s:
Sensitivity: 60.0%
95% CI: 40.61% to 77.32%
Specificity: 70.0%
95% CI: 34.84% to 92.97%
PPV: 85.71%
95% CI: 63.63% to 96.78%
NPV: 36.84%
95% CI: 16.63% to 61.62%
Figure 3: Post contrast sagittal
image
of
the
left
breast
demonstrating
area
of
enhancement in the upper outer
quadrant.
Figure 4: Indeterminate (Type II)
time-signal activity curve over the
enhancing lesion in the upper
outer left breast demonstrating
restricted diffusion.
Bibliography
1.
2.
3.
4.
5.
6.
Koh, D. et al. Diffusion-Weighted MRI in the Body:
Applications and Challenges in Oncology. American
Journal of Roentgenology. 2007; 188:1622-1635.
Kuhl C.K. et al. Dynamic Breast MR Imaging: Are Signal
Intensity Time Course Data Useful for Differential
Diagnosis of Enhancing Lesions? Radiology. 1999; 211:
101-110.
Schaefer, P.W. et al. Diffusion-weighted MR Imaging of
the Brain. Radiology. 2000; 217: 331-345.
Taouli, B. Extra-Cranial Applications of DiffusionWeighted MRI.
New York, New York: Cambridge
University Press; 2011: 88-89.
Woodhams R. et al. Identification of Residual Breast
Carcinoma Following Neoadjuvant Chemotherapy:
Diffusion-weighted Imaging Comparison with Contrastenhanced MR
imaging and Pathologic Findings.
Radiology. 2010; 254. 357-366.
Woodhams, R. et al. Diffusion-weighted Imaging of the
Breast;
Principles
and
Clinical
Applications.
Radiographics. 2011; 31: 1059-1084