MRI of the Morel-Lavallée lesion - a case series
Tajda Srot Volavc1, Mitja Rupreht1,2
1Radiology Department, University Medical Center Maribor, Maribor, Slovenia.
Introduction:
The aim of the study was to review the appearances of Morel-Lavallée (ML) lesions on magnetic resonance imaging (MRI).
Patients And Methods:
14 patients diagnosed with the ML lesion on MRI were analysed retrospectively (mean age = 35 years). Mechanism of injury, time frame from injury to MRI, location, shape, T1 and proton-density fat-suppression (PDFS) signal intensity (SI), presence of a (pseudo)capsule, septations or nodules within the collection, mass effect and fluid-fluid levels were analyzed. The Mellado and Bencardino classification was utilized to classify the lesions.
Results:
In most cases, mechanism of injury was distortion. Mean time frame between the injury and MRI was 17 days. Lesions were located around the knee in 9 patients and in the peritrochanteric region in 5 patients. Collections were fusiform in 12 patients and oval in 2 patients. 9 collections were T1 hypointense and PDFS hyperintense. 4 collections had intermediate T1 and high PDFS SI. 1 collection had intermediate T1 and PDFS SI. (Pseudo)capsule was noted in 3 cases. Septations or nodules were found in 4 cases. According to the Mellado and Bencardino, collections were classified as seroma (type 1) in 9, subacute hematoma (type 2) in 1 and chronic organizing hematoma (type 3) in 4 cases.
Conclusions:
Characteristic features of ML lesion include a fusiform fluid collection between the subcutaneous fat and the underlying fascia after shearing injury. Six types can be differentiated on MRI, with the seroma, the subacute hematoma and the chronic organizing hematoma being the commonest.
Insights
Morel-Lavallée lesions, fluid collections from shearing injuries, commonly appear fusiform on MRI. The study reviewed 14 cases, finding seromas, subacute, and chronic hematomas as the most frequent types.
Area of Science:
- Radiology
- Medical Imaging
- Orthopedic Surgery
Background:
- Morel-Lavallée (ML) lesions are post-traumatic fluid collections resulting from shearing forces.
- Understanding their appearance on Magnetic Resonance Imaging (MRI) is crucial for diagnosis and management.
Purpose of the Study:
- To review and characterize the MRI appearances of Morel-Lavallée lesions.
- To correlate imaging findings with injury mechanisms and lesion types.
Main Methods:
- Retrospective analysis of 14 patients with ML lesions diagnosed via MRI.
- Evaluation of injury mechanism, time to MRI, lesion location, shape, signal intensity (T1 and PDFS), and presence of capsule, septations, or nodules.
- Classification using the Mellado and Bencardino system.
Main Results:
- Most injuries involved distortion, with a mean time of 17 days from injury to MRI.
- Common locations included the knee (9 patients) and peritrochanteric region (5 patients).
- Lesions were typically fusiform (12 patients) and showed varied signal intensities; seroma (Type 1) was most common (9 cases).
Conclusions:
- Morel-Lavallée lesions present as fusiform fluid collections between subcutaneous fat and fascia post-shearing injury.
- MRI can differentiate six types, with seroma, subacute hematoma, and chronic organizing hematoma being the most prevalent.
- Characteristic MRI features aid in diagnosing and classifying ML lesions.
