Due to advances in engineering and technology, the field of MRI evolves at a steady pace. To keep up with these advancements, radiologists and technologists continue to saturate themselves with clinical research, hunting for cutting-edge strategies that will provide state-of-the-art image quality, regardless of the protocol prescribed.MRI has been utilized in mainstream radiology since the mid-1980s. Since that time, there has been a continuous stream of technological progress that is quite remarkable, most recently to include 3T scanning, functional MRI, and clinical spectroscopy of the brain, prostate, and liver. Large bore scanners are now routine, allowing better comfort for patients. Yet despite the tremendous innovations that have already taken place, the technology continues to move forward.
Whole body MRI
Whole body MRI has been available for some time but only recently has become an efficient method for total body screening. The idea of imaging the entire body at a single setting has been validated as an effective imaging protocol for a number of conditions.
The rationale for whole body MRI is clear: Many common diseases are systemic, that is, they are likely to involve the entire body. The most common application is for metastatic cancer evaluation, but cardiovascular disease also affects the entire body.
Whole body MRI does not necessarily require specialized scanners and coils, but these items are strongly recommended for efficient scan acquisition. Critically, the ability to “stitch” together multiple images acquired at different times and locations distinguishes MRI scanners that have the potential for rapid whole body scan acquisition. (See Figure 1.)
As indicated above, no billing codes currently cover dedicated whole body MRI. Separate charges or the multiple body parts make the exam prohibitively expensive, and insurance coverage for separate body parts is unlikely. In parts of Europe, whole body examination has been more common than in the U.S., particularly for self-paying patients and as a component of executive physical exams. If cost were not the driving force, would there be a medical need for whole body MRI?
In the current era of molecular imaging, the PET/CT scanner is considered the gold standard for any PET imaging. That paradigm may be poised for change with the advent of the MR/PET scanner. Three of the world’s leading manufacturers of imaging equipment–Philips, GE, and Siemens–have been focusing their research and development dollars on the concept of creating a system capable of acquiring MR and PET images together, with perfect fusion of the respective modalities.
Figure 2: Whole body single shot T2-weighted image fused with FDG-PET image. Multiple lesions (circles) are more readily identified on the MRI/PET fusion image (left).
|Figure 3: Fused MRI/PET image (left) obtained in approximately 25 minutes using FDG. The PET-only image obtained on the combination MRI/PET scanner is shown on the right. Small areas of focal activity are noted in the left flank (small circle) and right gluteal muscles (large circle).images/courtesy Dr. Bluemke|
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