Hassan Douis

The role of ultrasound in the assessment of post-operative complications following hip arthroplasty

Hip arthroplasty is one of the most commonly performed orthopedic procedures. Clinicians can be faced with the diagnostic dilemma of the patient presenting with a painful hip following arthroplasty and satisfactory post-operative radiographs. Identifying the cause of symptoms can be challenging and ultrasound is increasingly being utilized in the evaluation of potential soft tissue complications following hip surgery. In this article, we describe the common surgical approaches used during hip arthroplasty as this can influence the nature and location of subsequent complications. A review of the literature is presented along with the imaging appearances frequently encountered when imaging this patient population.

Myoepithelioma of bone with a novel FUS-POU5F1 fusion gene.

Myoepithelial tumours of soft tissue are rare lesions with a broad morphological and clinical spectrum. Previous studies have found EWSR1 rearrangements in approximately half of all cases and PBX1, ZNF44 and POU5F1 have been identified as recurrent fusion partners. In bone, only a small number of myoepithelial tumours have been described. We investigated an intraosseous myoepithelioma of the sacrum in a 54‐year‐old man without EWSR1 rearrangement for the presence of other fusion genes.

Imaging in the Diagnosis, Prognostication, and Management of Lower Limb Muscle Injury

Muscle injuries of the lower extremity are extremely common among athletes leading to significant morbidity and time out from competition. Furthermore, increasing athletic activity in the general population has resulted in lower limb muscle injuries becoming commonplace. It is therefore vital for the musculoskeletal radiologist to be familiar with the imaging findings of lower limb muscle injuries and to be aware of the role of imaging in the prognostication and management of these injuries. The most commonly injured lower limb muscles are the quadriceps, the hamstring complex, and the gastrocnemius muscles. This article reviews the biomechanical and imaging features of common acute muscle injuries of the lower extremity and evaluates the role of imaging in the prognosis of these sport injuries.

The role of diffusion-weighted MRI (DWI) in the differentiation of benign from malignant skeletal lesions of the pelvis

PURPOSE To evaluate the utility of Diffusion-weighted MRI in the differentiation of benign from malignant skeletal lesions of the pelvis. MATERIALS AND METHODS In this retrospective study 33 patients with indeterminate skeletal lesions of the pelvis were evaluated with DWI. Minimum, mean, maximum ADC-values of the skeletal lesions were measured followed by qualitative assessment of DWI. All patients underwent histological confirmation using CT-guided biopsy or surgical resection. The histology of the skeletal lesions was correlated with the findings on DWI. RESULTS There were 13 malignant lesions and 20 benign lesions. The mean, minimum and maximum ADC values (×10-6mm2/s) for benign skeletal lesions was higher than the mean ADC-values for malignant lesions (1422.2 vs 1263.7; 780.4 vs 771.8; 1969.6 vs 1676.8 respectively). These differences were however not statistically significant (P-values=0.29; 0.94; 0.149 respectively). The sensitivity, specificity, positive predictive value and negative predictive value for qualitative assessment of Diffusion-weighted MRI in the differentiation of benign from malignant skeletal lesions were: 53.9%, 85%, 70%, 73.9% respectively. Qualitative assessment of DWI (restricted diffusion versus non-restricted diffusion) allowed differentiation of benign from malignant skeletal lesions (P-value=0.0259). CONCLUSIONS Qualitative assessment of DWI may aid in the differentiation of benign skeletal lesions from malignant skeletal lesions of the pelvis. Although DWI has a low sensitivity in the distinction of the two disease entities, it may be a useful adjunct due to its relatively high specificity. This is of particular importance in lymphoma where biopsy may only show chronic inflammatory cells and hence may be false negative.

Is bone scintigraphy necessary in the initial surgical staging of chondrosarcoma of bone

ObjectiveTo assess the value of whole-body bone scintigraphy in the initial surgical staging of chondrosarcoma of bone.MethodsA retrospective review was conducted of the bone scintigraphy reports of a large series of patients with peripheral or central chondrosarcoma of bone treated in a specialist orthopaedic oncology unit over a 13-year period. Abnormal findings were correlated against other imaging, histological grade and the impact on surgical staging.ResultsA total of 195 chondrosarcomas were identified in 188 patients. In 120 (63.8%) patients the reports of bone scintigraphy noted increased activity at the site of one or more chondrosarcomas. In one patient the tumour was outside the field-of-view of the scan, and in the remaining 67 (35.6%) cases, there was increased activity at the site of the chondrosarcoma and further abnormal activity in other areas of the skeleton. Causes of these additional areas of activity included degenerative joint disease, Paget’s disease and in one case a previously undiagnosed melanoma metastasis. No cases of skeletal metastases from the chondrosarcoma were found in this series. Multifocal chondrosarcomas were identified in three cases. In two it was considered that all the tumours would have been adequately revealed on the initial MR imaging staging studies. In only the third multifocal case was an unsuspected, further presumed low-grade, central chondrosarcoma identified in the opposite asymptomatic femur. Although this case revealed an unexpected finding the impact on surgical staging was limited as it was decided to employ a watch-and-wait policy for this tumour.ConclusionThere is little role for the routine use of whole-body bone scintigraphy in the initial surgical staging in patients with chondrosarcoma of bone irrespective of the histological grade.

Musculoskeletal imaging: current and future trends

Advances in imaging technology and the increasing role of interventional procedures in musculoskeletal imaging have continued to stimulate research over recent years. This review summarises some recent articles on musculoskeletal radiology topics and looks forward to potential future developments in this exciting sub-speciality.

What are the differentiating clinical and MRI-features of enchondromas from low-grade chondrosarcomas?

ObjectivesTo evaluate the role of clinical assessment, conventional and dynamic contrast-enhanced MRI in differentiating enchondromas from chondrosarcomas of long bone.MethodsThe following clinical and MRI findings were assessed: age, gender, pain, pain attributable to lesion, tumour location, tumour length, presence, depth of endosteal scalloping, bone marrow oedema, soft tissue oedema, cortical destruction, periosteal reaction, bone expansion, macroscopic fat, calcification, soft tissue mass, haemorrhage, dynamic contrast-enhanced MRI. Clinical and MRI findings were compared with histopathological grading.ResultsSixty patients with central chondroid tumours were included (27 enchondromas, 10 cartilaginous lesions of unknown malignant potential, 15 grade 1 chondrosarcomas, 8 high-grade chondrosarcomas). Pain attributed to lesion, tumour length, endosteal scalloping > 2/3, cortical destruction, bone expansion and soft tissue mass were differentiating features between enchondromas and grade 1 chondrosarcomas. Dynamic contrast-enhanced MRI could not differentiate enchondromas from grade 1 chondrosarcomas.ConclusionsPreviously reported imaging signs of chondrosarcomas are useful in the diagnosis of grade 1 lesions but have lower sensitivity than in higher grade lesions. Deep endosteal scalloping is the most sensitive imaging sign of grade 1 chondrosarcomas. Pain due to the lesion is an important clinical sign of grade 1 chondrosarcomas. Dynamic contrast-enhanced MRI is not useful in differentiating enchondromas from grade 1 chondrosarcomas.Key Points• Differentiation of enchondroma from low-grade chondrosarcoma is challenging for radiologists and pathologists.• The utility of clinical assessment, conventional and dynamic contrast-enhanced MRI was uncertain.• Clinical assessment and conventional MRI aid in differentiating enchondromas from low-grade chondrosarcoma.• Dynamic contrast-enhanced MRI cannot differentiate enchondromas from grade 1 chondrosarcoma.