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Magnetic resonance imaging features in melanoma
H F Marx1, P M Colletti, J K Raval
1Los Angeles County-USC Medical Center, Department of Radiology 90033.
Magnetic Resonance Imaging
|January 1, 1990
Summary
Magnetic resonance imaging (MRI) reveals T1 and T2 relaxation time shortening in melanoma. However, atypical signal patterns exist, meaning absence of typical findings does not rule out melanoma.
Area of Science:
- Radiology
- Oncology
- Medical Imaging
Background:
- Paramagnetic compounds can shorten T1 and T2 relaxation times, a known characteristic of melanoma.
- Melanoma exhibits diverse signal behaviors on magnetic resonance imaging (MRI) across different body areas.
Purpose of the Study:
- To evaluate the MRI signal behavior of melanoma in various body locations.
- To analyze signal patterns using short and long repetition time (TR) and echo time (TE) sequences.
Main Methods:
- Twenty-seven melanoma sites were assessed using T1-weighted and T2-weighted MRI sequences.
- Lesions were categorized by signal intensity (high, low, intermediate) relative to fat and muscle.
- Four distinct signal patterns were identified.
Main Results:
- The typical pattern of high T1 and low T2 signal, indicating T1 and T2 shortening, was observed.
- Atypical patterns included low T1/high T2, high T1/high T2, and intermediate signals.
- Extraocular melanomas (1/14) and ocular melanomas (7/13) showed a tendency away from the typical pattern.
Conclusions:
- While T1 and T2 shortening patterns are typical for melanoma on MRI, their absence does not exclude the diagnosis.
- Melanoma can present with a variety of MR appearances, necessitating consideration of atypical findings.