Magnetic resonance signal alterations in the acute onset of heterotopic ossification in patients with spinal cord injury

• Published in: European radiology 2005-09, Vol.15 (9), p.1867-1875
• Main Authors: Wick, L, Berger, M, Knecht, H, Glücker, T, Ledermann, H P
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Bone marrow; Bone Marrow Diseases - diagnosis; Computed tomography; Contrast Media; Edema; Edema - diagnosis; Effusion; Fascia; Fascia - pathology; Female; Follow-Up Studies; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Muscles; Muscular Diseases - diagnosis; Musculoskeletal Diseases - diagnosis; Ossification (ectopic); Ossification, Heterotopic - diagnosis; Paraplegia - complications; Psoas Muscles - pathology; Quadriceps muscle; Quadriplegia - complications; Skin Diseases - diagnosis; Spinal cord injuries; Spinal Cord Injuries - complications; Synovial Fluid; Thigh - pathology; Tomography, X-Ray Computed
• ISSN: 0938-7994; 1432-1084
• DOI: 10.1007/s00330-005-2769-y

The purpose of our study was to evaluate magnetic resonance (MR) signal characteristics of acutely forming heterotopic ossification (HO) in paralyzed patients. Fourteen patients with spinal cord injury (female n=2, male n=12, mean age 38.3 years) and acute onset of radiographically proven HO had contrast-enhanced 1.5-T MRI within 13.4+/-18.3 days of clinical onset of symptoms. MR signal alterations of affected muscles, fascia, subcutaneous tissue, skin and adjacent bone were evaluated. A diffuse T2-hyperintense signal of multiple muscle groups was seen in all patients (bilateral in 12) involving quadriceps (n=13, 93%), adductors (n=13, 93%) and iliopsoas (n=12, 86%) with contrast enhancement in n=11 (79%), n=8 (57%) and n=8 (57%) patients. All patients had nonenhancing areas (mean size 2 x 3.5 x 5.8 cm) within diffusely enhancing muscles. HO formation occurred around these nonenhancing areas in four patients with computed tomography follow-up. Other MR findings included fascial edema (n=14, 100%), fascial enhancement (n=13, 93%), subcutaneous edema (n=13, 93%), subcutaneous enhancement (n=12, 86%), bone marrow edema (n=5, 36%), and joint effusion (n=12, 86%). MRI reveals mostly bilateral edema and enhancement of muscles, fascia and subcutaneous tissue during acute onset of HO. HO develops in the periphery of well-defined areas of no enhancement.