What is the role of MRI in the diagnosis of multiple myeloma?

Updated: Mar 15, 2019
  • Author: Michael E Mulligan, MD; Chief Editor: Felix S Chew, MD, MBA, MEd  more...
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MRI has high sensitivity for the early detection of marrow infiltration by myeloma cells. It has the ability to detect spinal cord or nerve compression and the presence of soft tissue masses and is recommended for the workup of solitary bone plasmacytoma. [28]  MRI is useful for imaging multiple myeloma because of its superior soft-tissue contrast resolution. The typical appearance of a myeloma deposit is a round, low signal intensity (relative to muscle) focus on T1-weighted images, which becomes high in signal intensity on T2-weighted sequences. (The images below demonstrate the appearance of a typical myeloma lesion in the proximal humerus.) Myeloma lesions tend to enhance with gadolinium administration. In addition, diffuse areas of marrow replacement may be seen, resulting in large regions of low T1-weighted signal. [29, 28, 29, 30, 31, 14]

Coronal T1-weighted magnetic resonance image throu Coronal T1-weighted magnetic resonance image through a myeloma lesion of the humerus. This image shows that the lesion has a low signal intensity. The outer cortical margin is eroded but intact; however, the lesion has transgressed the inner cortex.
A T1-weighted magnetic resonance image of the hume A T1-weighted magnetic resonance image of the humerus. This image demonstrates a predominantly hypointense to isointense myelomatous lesion in the medullary space of the diaphysis. The lesion extends through the anterior aspect of the cortex.
A T2-weighted, fat-suppressed magnetic resonance i A T2-weighted, fat-suppressed magnetic resonance image of a myeloma lesion of the humerus. This image demonstrates the lesion is hyperintense on this sequence, a typical finding.

Fast whole body techniques are available on some magnet systems. [27] MRI can also provide important information for prognosis. One study of 611 myeloma patients showed that the presence of more than 7 focal lesions was an independent predictor of poorer prognosis and that resolution of all focal lesions was an indicator of superior survival. [30]  Some reports indicate that a sequential increase in the number of focal lesions (without a specific cutoff number) is associated with an adverse prognosis. [31]

(See the images of myeloma of the shoulder below.)

A T1-weighted magnetic resonance image of the shou A T1-weighted magnetic resonance image of the shoulder. This image shows the full extent of myelomatous involvement within the glenoid and coracoid process.
A T2-weighted, fat-suppressed magnetic resonance i A T2-weighted, fat-suppressed magnetic resonance image of the shoulder (same patient as in the previous image). This image demonstrates the myeloma lesion is hyperintense.

Gadolinium-based contrast agents have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness.

Unfortunately, almost any musculoskeletal tumor has the same signal-intensity profile and enhancement pattern as myeloma. MRI, although sensitive to the presence of disease, is not disease specific. Additional tests must be used to diagnose myeloma, such as measurement of gamma-globulin levels and direct aspiration of bone marrow to assess for plasmacytosis. Because of this, MRI may understage or overstage patients with myeloma.

In patients with extraosseous lesions, MRI is the study of choice to define the degree of involvement and to evaluate for cord compression.

A study of 27 newly diagnosed patients with multiple myeloma found that the combination of anatomic information from conventional MRI with functional information from  dynamic contrast-enhanced MRI and diffusion-weighted imaging was useful for monitoring therapy. [32]

PET/MRI was compared with PET/CT in 30 multiple myeloma patients. The hybrid PET/MRI provided good image quality in all cases without artifacts and identified 65 of the 69 lesions that were detected with PET/CT (94.2%). However, both standardized uptake value (SUV) average and SUVmax were significantly higher on PET/CT than on PET/MRI. [33]


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