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

Abstract

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.

BMP-9-induced muscle heterotopic ossification requires changes to the skeletal muscle microenvironment

“…First, the modification of blood flow could induce ischemia and stasis at the site of injury. Such a modification in gas exchange was well described in paraplegic individuals (47,48) and after total hipreplacement procedures, (49) two conditions that are often associated with HO. Second, inflammation is known to occur following muscle damage.…”

Identifying the Cellular Mechanisms Leading to Heterotopic Ossification

“…These include pain, loss of joint mobility, skin ulceration, overlying skin graft failure, muscle and neurovascular entrapment, and prosthetic limb fitting difficulties [9]. Clinically, HO first presents with pain and swelling in the affected limb [10]. This can cause difficulty with diagnosis as the symptoms overlap with infection and deep vein thrombosis, which are also common diagnoses in these patients.…”

Serial Ultrasonography for Early Detection and Follow-up of Heterotopic Ossification in Stroke

“…Originally used only for preoperative structure evaluation, MRI was recently found to be sensitive for approximately 20 days after disease onset. Findings include areas with no enhancement in regions of diffuse muscle edema, representing areas of necrosis and hemorrhage [14]. However, these findings are not specific [15,16].…”