How to Report: Hip MRI

Writing a good magnetic resonance imaging (MRI) hip report requires a sound understanding of hip anatomy, imaging, and related pathologies. The structures of the hip most prone to pathology are the articular surfaces, labrum, subchondral bone, and gluteal tendons. Particular attention should be paid to abnormal hip morphology that is relatively common and can manifest as internal or external hip derangement. It is essential to appreciate and report the specific features of each pathology that carry clinical significance to aid patient management. This article is aimed at trainee radiologists and those less experienced with reporting hip MRI, focusing on the essential features to comment on and providing examples of terminology to use and MR images to illustrate these features.

Reliability of a Novel Scoring System for MRI Assessment of Severity in Gluteal Tendinopathy: The Melbourne Hip MRI Score

Background: Gluteal tendinopathy is commonly reported in the literature, but there is a need for a validated magnetic resonance imaging (MRI)-based scoring system to grade the severity of the tendinopathy. Purpose: To use intra- and interobserver reliability to validate a new scoring system, the Melbourne Hip MRI (MHIP) score, for assessing the severity of gluteal tendinopathy. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: The MHIP score assesses gluteal tendinopathy according to each 1 of 5 categories: (1) extent of tendon pathology (maximum 5 points); (2) muscle atrophy (maximum 4 points); (3) trochanteric bursitis (maximum 4 points); (4) cortical irregularity (maximum 3 points); and (5) bone marrow edema (maximum 1 point), with an overall range of 0 to 17 (most severe). A total of 41 deidentified MRI scans from 40 patients diagnosed with gluteal tendinopathy (mean baseline age, 57.44 ± 25.26 years; 4 male, 36 female) were read and graded according to MHIP criteria by 2 experienced musculoskeletal radiologists. The radiologists were blinded to previous reports, and the scans were read twice within a 2-month period. Statistical analysis using the intraclass correlation coefficient (ICC) was used to determine intra- and interobserver reliability and mean/range for the MHIP scores. Results: Of a total of 123 readings, the mean MHIP score (±SD) was 3.93 ± 2.24 (range, 0-17 points). The MHIP score demonstrated excellent reliability for determining the severity of gluteal tendinopathy on MRI. The ICC for intra- and interobserver reliability was 0.81 (95% CI, 0.67-0.89) and 0.78 (95% CI, 0.62-0.87), respectively. Conclusion: The MHIP score had excellent intra- and interobserver reliability in scoring gluteal tendinopathy. This score allows gluteal tendon pathology to be graded prior to treatment and to be used for standardized comparisons between results in future research undertaking radiological review of gluteal tendinopathy.

MRI risk factors for development of avascular necrosis after closed reduction of developmental dysplasia of the hip: Predictive value of contrast-enhanced MRI

Purpose The purpose of this study was to identify imaging risk factors on contrast-enhanced hip MRI after closed reduction of developmental dysplasia of the hip (DDH) that could predict future development of avascular necrosis (AVN) of the femoral head. Materials and methods Fifty-eight infants (F: M = 53: 5, aged 3–18 months) who underwent immediate postoperative contrast-enhanced hip MRI after closed reduction of DDH were included in this study. Quality of reduction (concentric vs eccentric reduction with or without obstacles), abduction angle of the hip, presence of ossific nucleus, and pattern of contrast enhancement of the femoral head were retrospectively evaluated on MRI. Interobserver agreement of contrast enhancement pattern on MRI were evaluated by two radiologists. Development of AVN was determined through radiographic findings at 1 year after reduction. Results AVN of the femoral head developed in 13 (22%) of 58 patients. Excessive abduction of the hip joint (OR 4.65, [95% CI 1.20, 18.06] and global decreased enhancement of the femoral head (OR 71.66, [95% CI 10.54, 487.31]) exhibited statistically significant differences between the AVN and non-AVN groups (P < 0.05). Eccentric reduction (P = 0.320) did not show statistically significant difference between two groups and invisible ossific nucleus (P = 0.05) showed borderline significance. Multi-variable logistic regression indicated that global decreased enhancement of the femoral head was a significant risk factor of AVN (OR 27.92, 95% CI [4.17, 350.18]) (P = 0.0031). Interobserver agreement of contrast enhancement pattern analysis and diagnosis of AVN were good (0.66, 95% CI [0.52, 0.80]). Conclusion Contrast-enhanced hip MRI provides accurate anatomical assessment of the hip after closed reduction of DDH. Global decreased enhancement of the femoral head could be used as a good predictor for future development of AVN after closed reduction of DDH.

MON-337 Peripheral Neurological Complications in Pregnancy- Is Idiopathic Transient Osteoporosis of Pregnancy Concerning?

Idiopathic transient osteoporosis of pregnancy (ITOP) is a rare and under-reported condition that has affected healthy pregnancies. ITOP usually presents in the final trimester of a normal pregnancy. Radiographic studies detect drastic loss of bone mass, elevated rates of turnover in the bone, and edema in the affected portion. We present a 26-year-old previously healthy woman, who was admitted at 39 weeks of gestation with severe left hip pain and inability to walk for one month.The pain was constant, progressive, involving left lower limb, and associated with numbness and weakness. Neurological exam revealed diminished power in the left hip (motor power was 2/5), and inability to stand and walk due to pain in the left hip. She was unable to stand by herself. Investigations revealed anemia, low vitamin B12, low vitamin D and magnesium. Bilateral hip MRI showed increased T2WI signal in the left femoral head consistent with idiopathic transient osteoporosis of the left hip (ITOP). DXA scan showed bone mass density (BMD) below expected for age.The patient had induced vaginal labor without complication. The left hip pain improved after delivery. She was treated conservatively with Calcium, Magnesium and vitamin D. The patient symptoms completely resolved in 3 months post-delivery. DXA scan and Hip MRI at 1 year interval showed normal BMD and complete resolution of previous bone marrow edema and changes seen in MRI hip. This case report serves to highlight the effect of pregnancy on bone mass during third trimester which may result in transient osteoporosis of pregnancy leading to weakness and gait disturbance. Clinical symptoms can be misdiagnosed as a peripheral neurological complications instead of bone metabolism changes of pregnancy.

Anatomical analysis of the pelvis to identify any predisposing anatomical factors for ischiofemoral space pathology: a retrospective study

Objective: Anatomical analysis of the hips and pelvis was performed using MRI to evaluate morphological characteristics and associations between them. We identified correlations between the ischiofemoral space (IFS), quadratus femoris space (QFS), femoral version angle (FVA) and cervicodiaphyseal angle (CDA). Methods: This study involved a retrospective search of a database of consecutive reports of adult hip MRI examinations carried out between January and September 2016. Patients with a medical history likely to affect pelvic and hip morphometry were excluded. Results: A total of 137 adult patients were enrolled in the study (45.3% males and 54.7% females), with a mean age of 50.16 ± 13.87 years. The mean IFS was 20.88 ± 5.96 mm, mean QFS was 15.2 ± 6.18 mm, mean FVA was 12.43 ± 6.98, and mean CDA was 121.27 ± 4.6°. The IFS measurements were significantly correlated with femoral measurements (p = 0.025). These visible differences showed a slight negative relationship (−0.191), and females had a smaller distance between these anatomical structures than males (p < 0.001). Females had a significantly smaller QFS than males (12.42 ± 5.94 vs 18.73 ± 4.48 mm, p = 0.000). There was a small but significant positive relationship between CDA and FVA (p = 0.022), with a correlation coefficient of 0.195. Conclusion: A higher FVA was correlated with a smaller IFS. Furthermore, an increase in the CDA appeared in tandem with an increase in the FVA. Advances in knowledge: A single conventional MRI sequence can alert us to how anatomical factors could predispose individuals to a decrease in IFS.