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Integrated whole body MR/PET: where are we?

Yoo HJ, Lee JS, Lee JM - Korean J Radiol (2015)

Bottom Line: Whole body integrated magnetic resonance imaging (MR)/positron emission tomography (PET) imaging systems have recently become available for clinical use and are currently being used to explore whether the combined anatomic and functional capabilities of MR imaging and the metabolic information of PET provide new insight into disease phenotypes and biology, and provide a better assessment of oncologic diseases at a lower radiation dose than a CT.Various early clinical applications of integrated MR/PET are also addressed.Finally, the workflow issues of integrated MR/PET, including maximizing diagnostic information while minimizing acquisition time are discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea.

ABSTRACT
Whole body integrated magnetic resonance imaging (MR)/positron emission tomography (PET) imaging systems have recently become available for clinical use and are currently being used to explore whether the combined anatomic and functional capabilities of MR imaging and the metabolic information of PET provide new insight into disease phenotypes and biology, and provide a better assessment of oncologic diseases at a lower radiation dose than a CT. This review provides an overview of the technical background of combined MR/PET systems, a discussion of the potential advantages and technical challenges of hybrid MR/PET instrumentation, as well as collection of possible solutions. Various early clinical applications of integrated MR/PET are also addressed. Finally, the workflow issues of integrated MR/PET, including maximizing diagnostic information while minimizing acquisition time are discussed.

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Related in: MedlinePlus

63-year-old male had colon cancer with brain, lung, and mediastinal lymph node (LN) metastasis.A. Coronal fused FDG-MR/PET image showed mediastinal LNs (arrows) with increased FDG uptake. B. Axial fused FDG-MR/PET image showed metastatic retroperitoneal LN (arrow) and metastatic bone lesion at L5 vertebral body (arrowhead). C. FLAIR image demonstrates brain metastasis in left temporal lobe (arrow). D. Reconstructed sagittal fused FDG-MR/PET image showed bone metastasis in cervical and lumbar spine (arrows). FDG = fluorodeoxyglucose, FLAIR = fluid attenuated inversion recovery, MR/PET = magnetic resonance imaging/positron emission tomography
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Figure 6: 63-year-old male had colon cancer with brain, lung, and mediastinal lymph node (LN) metastasis.A. Coronal fused FDG-MR/PET image showed mediastinal LNs (arrows) with increased FDG uptake. B. Axial fused FDG-MR/PET image showed metastatic retroperitoneal LN (arrow) and metastatic bone lesion at L5 vertebral body (arrowhead). C. FLAIR image demonstrates brain metastasis in left temporal lobe (arrow). D. Reconstructed sagittal fused FDG-MR/PET image showed bone metastasis in cervical and lumbar spine (arrows). FDG = fluorodeoxyglucose, FLAIR = fluid attenuated inversion recovery, MR/PET = magnetic resonance imaging/positron emission tomography

Mentions: MR imaging has been reported to be of higher accuracy than PET/CT when assessing the liver and bone (Fig. 6) for distant metastases (1, 5, 45, 77, 78, 79, 80, 81, 82). In a recent study (45) which compared PET/CT scanning and a subsequent MR/PET with an unenhanced coronal T1-weighted turbo spin-echo (T1WI-TSE) sequence for the analysis of bone lesions in 119 patients with primary malignancies, the anatomic delineation and allocation of bone lesions was significantly superior with T1WI-TSE MRI compared to CT or T1-weighted VIBE Dixon MRI. No significant difference in the correct classification of malignant bone lesions was found among the image sets. These results suggest that MR/PET, with the diagnostic T1WI-TSE sequence, could be useful for diagnosing primary bone tumors, early bone marrow infiltration, and tumors with low avidity to FDG. Underestimation of FDG uptake in bone was also found on MR/PET due to an under-correction of cortical bone when creating an MR-based attenuation map, although there was a highly significant correlation between the SUVs for MR/PET and PET/CT (p < 0.0001) (45).


Integrated whole body MR/PET: where are we?

Yoo HJ, Lee JS, Lee JM - Korean J Radiol (2015)

63-year-old male had colon cancer with brain, lung, and mediastinal lymph node (LN) metastasis.A. Coronal fused FDG-MR/PET image showed mediastinal LNs (arrows) with increased FDG uptake. B. Axial fused FDG-MR/PET image showed metastatic retroperitoneal LN (arrow) and metastatic bone lesion at L5 vertebral body (arrowhead). C. FLAIR image demonstrates brain metastasis in left temporal lobe (arrow). D. Reconstructed sagittal fused FDG-MR/PET image showed bone metastasis in cervical and lumbar spine (arrows). FDG = fluorodeoxyglucose, FLAIR = fluid attenuated inversion recovery, MR/PET = magnetic resonance imaging/positron emission tomography
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4296276&req=5

Figure 6: 63-year-old male had colon cancer with brain, lung, and mediastinal lymph node (LN) metastasis.A. Coronal fused FDG-MR/PET image showed mediastinal LNs (arrows) with increased FDG uptake. B. Axial fused FDG-MR/PET image showed metastatic retroperitoneal LN (arrow) and metastatic bone lesion at L5 vertebral body (arrowhead). C. FLAIR image demonstrates brain metastasis in left temporal lobe (arrow). D. Reconstructed sagittal fused FDG-MR/PET image showed bone metastasis in cervical and lumbar spine (arrows). FDG = fluorodeoxyglucose, FLAIR = fluid attenuated inversion recovery, MR/PET = magnetic resonance imaging/positron emission tomography
Mentions: MR imaging has been reported to be of higher accuracy than PET/CT when assessing the liver and bone (Fig. 6) for distant metastases (1, 5, 45, 77, 78, 79, 80, 81, 82). In a recent study (45) which compared PET/CT scanning and a subsequent MR/PET with an unenhanced coronal T1-weighted turbo spin-echo (T1WI-TSE) sequence for the analysis of bone lesions in 119 patients with primary malignancies, the anatomic delineation and allocation of bone lesions was significantly superior with T1WI-TSE MRI compared to CT or T1-weighted VIBE Dixon MRI. No significant difference in the correct classification of malignant bone lesions was found among the image sets. These results suggest that MR/PET, with the diagnostic T1WI-TSE sequence, could be useful for diagnosing primary bone tumors, early bone marrow infiltration, and tumors with low avidity to FDG. Underestimation of FDG uptake in bone was also found on MR/PET due to an under-correction of cortical bone when creating an MR-based attenuation map, although there was a highly significant correlation between the SUVs for MR/PET and PET/CT (p < 0.0001) (45).

Bottom Line: Whole body integrated magnetic resonance imaging (MR)/positron emission tomography (PET) imaging systems have recently become available for clinical use and are currently being used to explore whether the combined anatomic and functional capabilities of MR imaging and the metabolic information of PET provide new insight into disease phenotypes and biology, and provide a better assessment of oncologic diseases at a lower radiation dose than a CT.Various early clinical applications of integrated MR/PET are also addressed.Finally, the workflow issues of integrated MR/PET, including maximizing diagnostic information while minimizing acquisition time are discussed.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea.

ABSTRACT
Whole body integrated magnetic resonance imaging (MR)/positron emission tomography (PET) imaging systems have recently become available for clinical use and are currently being used to explore whether the combined anatomic and functional capabilities of MR imaging and the metabolic information of PET provide new insight into disease phenotypes and biology, and provide a better assessment of oncologic diseases at a lower radiation dose than a CT. This review provides an overview of the technical background of combined MR/PET systems, a discussion of the potential advantages and technical challenges of hybrid MR/PET instrumentation, as well as collection of possible solutions. Various early clinical applications of integrated MR/PET are also addressed. Finally, the workflow issues of integrated MR/PET, including maximizing diagnostic information while minimizing acquisition time are discussed.

Show MeSH
Related in: MedlinePlus