Improving Specificity of Breast MRI Using Prone PET and Fused MRI and PET 3D Volume Datasets

Abstract

MRI is a sensitive method for detecting invasive breast cancer, but it lacks specificity. To examine the effect of combining PET with MRI on breast lesion characterization, a prototype positioning device was fabricated to allow PET scans to be acquired in the same position as MRI scans-that is, prone. Methods: To test the hypothesis that fusion of 18 F-FDG PET and MRI scans improves detection of breast cancer, 23 patients with suspected recurrent or new breast cancer underwent a routine whole-body PET scan, a prone PET scan of the chest, and a routine breast MRI scan. The attenuation-corrected prone PET and MRI datasets were registered twice by different operators. The fusion results were judged for quality by visual inspection and statistical analysis. A joint reading of the MRI and PET scans side by side and integrated images was performed by a nuclear medicine physician and a radiologist. Sensitivity and specificity of MRI and combined MRI and PET scans were calculated on the basis of pathology reports or at least 1 y of clinical and radiologic follow-up. Results: All fusions were verified to be well matched using specific anatomic criteria. A total of 45 lesions was assessed. Lesion size range was 0.6 to 10.0 cm. Of the 44 breasts examined, 29 were suspicious for cancer, of which 15 were found to be positive on surgical excision. In lesion-by-lesion analysis, sensitivity and specificity of MRI alone were 92% and 52%, respectively; after MRI and PET fusion, they were 63% and 95%, respectively. The positive predictive value and the negative predictive value for MRI alone were 69% and 85%, respectively; after MRI and PET fusion, they were 94% and 69%, respectively. Conclusion: Acquisition of prone PET scans using the new positioning device permitted acquisition of prone scans suitable for fusion with breast MRI scans. Fused PET and MRI scans increased the specificity of MRI but decreased the sensitivity in this small group of patients. Additional data are needed to confirm the statistical significance of these preliminary findings.

18F-FDG PET in Detecting Primary Breast Cancer

“…We read the article by Moy et al (1) with great interest. This is one of the few studies that have investigated the role of PET/MRI in evaluating primary breast cancer.…”

Evaluation of Novel Genetic Algorithm Generated Schemes for Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI) Image Fusion

“…Significant effort has been devoted to developing registration procedures suitable for medical images in general and more recently PET/MRI breast images [12,[18][19][20]. The registration procedure was selected for this work based on its efficiency, consistency, operator independence, and suitability for use in a clinical environment [18][19][20].…”

“…Initial experience with combined PET (functional imaging) and MRI (anatomical localization) has yielded positive results, providing benefits compared to either modality alone [12][13][14][15]. While no clinical scanners currently exist capable of acquiring images from both modalities, prototypes have been developed [16,17], and commercial devices are in the not too distant future.…”

New developments in imaging and functional biomarker technology for the assessment and management of cancer patients

“…The development of combined PET/MRI scanners for whole-body applications has great potential for revolutionizing functional imaging [25][26][27][28][29][30][31][32][33]. MRI offers the benefit of improved soft tissue contrast and does not expose patients to the ionizing radiation of CT.…”

“…Used in conjunction with PET/CT (low dose for attenuation correction) for whole-body surveys, PET/MRI could provide a unique biochemical, physiologic and metabolic picture of the tumor for guiding therapy and assessing therapy response [25]. Software fusion of PET/CT and MRI has demonstrated diagnostic benefit over either modality used alone [26][27][28][29]. Hardware-combined PET/MRI prototype scanners appear promising [30].…”