Comparison of magnetic resonance imaging and computed tomography for bone assessment of neurogenic heterotopic ossification of the hip: a preliminary study

Background Neurogenic heterotopic ossification (NHO) is a frequent complication, often involving the hip. The functional impact may require surgical management and pre-surgical imaging assessment is necessary, usually by computed tomography (CT). We aimed to compare the performances of magnetic resonance imaging (MRI) and CT for bone assessment on pre-surgical imaging of the heterotopic ossifications and their features in NHO of the hip. Methods This single-center prospective preliminary study included all patients who underwent surgery for NHO with joint limitation from July 2019 to March 2020. All patients had a CT after biphasic iodinated solution injection and an MRI including T1-weighted, STIR and ZTE sequences. Standardized reports were completed for both exams for each patient, evaluating location, implantation and fragmentation of NHO, relation to the joint capsule and bone mineralization, then were compared. Results Seven patients from 32 to 70 years old (mean = 50.2 ± 17.2 years) were evaluated. NHO were bilateral in 2 patients, for a total of nine hips: six right hips and three left hips. Observed concordance rates between MRI and CT were, respectively, 94.4% for location, 100% for circumferential extension, 87.3% for implantation 88.9% for fragmentation, 77.8% for relation to the joint capsule and 66.7% for bone mineralization. It was 100% for femoral neck fracture and osteonecrosis of the femoral head. Conclusion This preliminary study suggests that pre-surgical MRI imaging should be considered as effective as CT for bone assessment of NHO and their features. Trial registration: ClinicalTrials.gov, NCT03832556. Registered February 6, 2019, https://clinicaltrials.gov/ct2/show/NCT03832556.

THE BONE MICROSTRUCTURE IDENTIFICATION MODEL BASED ON BACKSCATTER MODE OF ULTRASOUND

Osteoporosis is defined by a decrease in bone mass and a deterioration in bone microstructure. It is a major public health issue and a significant economic burden for both individuals and society. Thus, monitoring bone mass and structure is necessary to prevent bone fragility and osteoporosis. This study aimed to develop a prototype of quantitative ultrasound (QUS) and to evaluate the feasibility of backscatter mode for the bone assessment. Ultrasound (US) signals that propagate through the bone can be characterized by comparing the signal from both transmitter and receiver transducers. The US backscattered signal depends on the characteristic of both medium and transducer. In this study, we analyzed the attenuated signal based on the parameters: type of bone (compact and spongy), type of coupling medium (air, starch, and gel), the angle between transducers and bone (30o, 60o, and 90o), and transducer distance (0, 10, 5, 15, 20 and 25 cm). We use only 1 MHz transducer frequency. The prototype has been evaluated by Digital Oscilloscope and LabVIEW user interface to observe received signals. The results of this study showed that there was a difference in amplitude of the US signal from compact and spongy bones. The amplitude is directly proportional to acoustic impedance and inversely proportional to the distance between transducers. There is a negative correlation between bone microstructure to attenuation, and compact bones have a greater attenuation coefficient than spongy bones.

Clinical and radiological examination of bony-mediated shoulder instability

The coexistence of glenoid and humeral head bone defects may increase the risk of recurrence of instability after soft tissue repair. Revealed factors in medical history such as male gender, younger age of dislocation, an increasing number of dislocations, contact sports, and manual work or epilepsy may increase the recurrence rate of instability. In physical examination, positive bony apprehension test, catching and crepitations in shoulder movement may suggest osseous deficiency. Anteroposterior and axial views allow for the detection of particular bony lesions in patients with recurrent anterior shoulder instability. Computed Tomography (CT) with multiplanar reconstruction (MPR) and various types of 3D rendering in 2D (quasi-3D-CT) and 3D (true-3D-CT) space allows not only detection of glenoid and humeral bone defects but most of all their quantification and relations (engaging/not-engaging and on-track/off-track) in the context of bipolar lesion. Magnetic resonance imaging (MRI) is increasingly developing and can provide an equally accurate measurement tool for bone assessment, avoiding radiation exposure for the patient. Cite this article: EFORT Open Rev 2020;5:815-827. DOI: 10.1302/2058-5241.5.200049