The uses and limitations of whole-body magnetic resonance imaging

Abstract

Background: Whole-body magnetic resonance imaging (WB-MRI) is a modern imaging method, free of ionizing radiation, which provides high-resolution display of individual organ systems and of the anatomy of the entire body.

Methods: Selective literature review

Results: Multi-channel WB-MRI scanners enable both the high-resolution imaging of the entire body and focused studies of individual organs, through the use of various sequence techniques and contrast modes. The initial application of combined cardiovascular and oncological imaging protocols for the screening of asymptomatic persons has already revealed many cases of cardiovascular disease and of tumors with serious clinical implications. The diagnostic accuracy of M staging with WB-MRI lies in the range of 93% to 97%. WB-MRI provides good contrast of the bone marrow, and has thus been used for the diagnosis of malignant bone marrow disease as well: in particular, it is especially sensitive for multiple myeloma and plays an important role in prognostication and therapeutic decision-making in this disorder. To date, WB-MRI has not been shown to be superior to other diagnostic techniques with respect to hard endpoints, such as prolongation of survival. It also carries the risk of false positive findings.

Conclusion: Despite these encouraging results, undirected screening by WB-MRI without an appropriate indication, as is currently being practiced in many institutions, is decidedly inadvisable in view of its predicted diagnostic yield below 2% and the lack of evidence for its cost-effectiveness.

Figure 1

From multimodal diagnosis to whole-body examination: repeat staging in a 29-year-old female patient after treatment for breast cancer and an increase in levels of tumor markers during follow-up

Figure 2

A 65-year-old patient with multiple myeloma