Clinics in diagnostic imaging (197). Left ischiofemoral impingement syndrome

A 48-year-old woman presented with progressive left hip pain over six months, along with left lower limb weakness for two weeks. Magnetic resonance imaging of the left hip showed narrowing of the left ischiofemoral space, oedema of the left quadratus femoris muscle and left sciatic nerve, and mild bone marrow oedema of the left ischial tuberosity. The diagnosis of left ischiofemoral impingement syndrome was made. The imaging features of ischiofemoral impingement syndrome and the associated aetiologies and complications are discussed.

Diagnostic value of MRI measurement in ischiofemoral impingement syndrome / 中国医学影像技术

Objective To investigate the diagnostic value of MRI in patients with ischiofemoral impingement syndrome (IFIS). Methods MRI data of 70 patients with IFIS (IFIS group) and 40 normal volunteers (control group) were analyzed retrospectively. The width of ischial femoral space (IFS) and quadratus femoris space (QFS) were measured on axial fat suppression T2WI, while the angle of sciatic bone was measured on axial T1WI, and the femoral neck shaft angle was measured on coronal T2WI, and then were compared between the two groups. The correlation between the width of IFS and the other three parameters was analyzed, and ROC curve was drawn to evaluate the diagnostic efficacy for IFIS. The degree of edema and fat infiltration of the quadratus femoris in IFIS group were evaluated, and the differences of IFS width among different grades were compared. Results In IFIS group, the IFS width, QFS width, ischium angle and femoral neck shaft angle was (11.76±2.22)mm, (8.33±2.20)mm, (132.59±1.39)° and 132.70(131.18,134.13)°, respectively, and the differences between the two groups were statistically significant (all P<0.001). The area under ROC curve in diagnosis of IFIS with IFS width, QFS width, ischium angle and femoral neck shaft angle was 1.000, 0.999, 0.996 and 0.975, respectively (all P<0.001). There was positive correlation between IFS width and QFS (r=0.743, P<0.001), negative correlation between IFS width and ischium angle and femoral neck shaft angle (r=-0.273, P=0.022; r=-0.332, P=0.005). The overall differences in IFS width among different grades of femoral quadratus edema and fat infiltration in IFIS patients were statistically significant (both P<0.05). Conclusion IFS and QFS of IFIS patients are obviously narrow. Edema and fat infiltration of quadratus femoris are common MRI findings in IFIS patients.

Utility of False Profile View for Screening of Ischiofemoral Impingement / 대한고관절학회지

PURPOSE: Ischiofemoral impingement (IFI)-primarily diagnosed by magnetic resonance imaging (MRI)-is an easily overlooked disease due to its low incidence. The purpose of this study was to evaluate the usefulness of false profile view as a screening test for IFI. MATERIALS AND METHODS: Fifty-eight patients diagnosed with IFI between June 2013 and July 2017 were enrolled in this retrospective study. A control group (n=58) with matching propensity scores (age, gender, and body mass index) were also included. Ischiofemoral space (IFS) was measured as the shortest distance between the lateral cortex of the ischium and the medial cortex of lesser trochanter in weight bearing hip anteroposterior (AP) view and false profile view. MRI was used to measure IFS and quadratus femoris space (QFS). The receiver operating characteristics (ROC), area under the ROC curve (AUC) and cutoff point of the IFS were measured by false profile images, and the correlation between the IFS and QFS was analyzed using the MRI scans. RESULTS: In the false profile view and hip AP view, patients with IFI had significantly decreased IFS (P < 0.01). In the false profile view, ROC AUC (0.967) was higher than in the hip AP view (0.841). Cutoff value for differential diagnosis of IFI in the false profile view was 10.3 mm (sensitivity, 88.2%; specificity, 88.4%). IFS correlated with IFS (r=0.744) QFS (0.740) in MRI and IFS (0.621) in hip AP view (P < 0.01). CONCLUSION: IFS on false profile view can be used as a screening tool for potential IFI.

A Case of Ischiofemoral Impingement Syndrome as a Differential Diagnosis of Ankylosing Spondylitis

Ischiofemoral impingement (IFI) syndrome is an uncommon cause of gluteal and hip pain. We report on a case of a 20-year-old man who presented with chronic gluteal and hip pain with low back pain without a history of trauma or surgery. He was misdiagnosed with ankylosing spondylitis (AS) at another clinic. The patient was finally diagnosed with IFI syndrome according to pelvic magnetic resonance imaging findings at our hospital. After two weeks of medical and physical treatment, his pain showed gradual improvement. Because IFI syndrome is rarely reported in male patients, it might be misdiagnosed as AS. Therefore, IFI syndrome should be considered as a differential diagnosis of AS, particularly in young male patients with atypical pain characteristics.