Bedside ultrasound in early diagnosis of neurogenic heterotopic ossification in patients with acquired brain injury.

Objective: To illustrate ultrasound (US) and power Doppler US (PDUS) aspects of neurogenic heterotopic ossification (NHO) in consecutive patients with severe acquired brain injury, to evaluate the role of bedside US and PDUS in early diagnosis of NHO, to study incidence and outcome of NHO in this neurorehabilitative setting.

Methods: Ninety-two consecutive patients with severe acquired brain injury underwent clinical and laboratory screening to pose suspect of NHO. In 6/92 patients bedside US examination confirmed the clinical suspect of NHO. US diagnosis of NHO was then confirmed by other imaging methods. All affected patients started therapy with indometacin, disodium etidronate, 6-methylprednisolone and they were followed-up for 1 year to evaluate the outcome.

Results: The incidence of NHO in this setting was 6.5% (only one patient with multifocal involvement). In hip NHO US demonstrated the classical pattern of zone phenomenon, and PDUS demonstrated vascular signals within mineralized NHO and in the outer hypoechoic area. No vascular signal was observed in the central hypoechoic core. In knee and elbow NHO only a heterogeneously hypoechoic mass or hyperechoic mineralized mass were respectively evident, with vascular signals within the lesions at PDUS. Spectral wave analysis (SWA) demonstrated low resistance vessels in NHO. After 1 year of therapy only one patient showed a severe ankylosis of the hips.

Conclusions: Bedside US is a safe, cheap and useful tool in diagnosis of NHO and it allows to start therapy in early stages of NHO formation. PDUS adds data about neoangiogenetic activity of early NHO.