The role of multidetector CT arthrography in the investigation of suspected intra-articular hip pathology.

The aim of this study was to evaluate the role of multidetector CT (MDCT) arthrography in the diagnosis of intra-articular hip pathology. A retrospective review of 96 patients who had undergone CT hip arthrography was performed. Data regarding the presence of a labral tear, paralabral cyst, chondral loss, acetabular version, femoral morphology and fibrocystic change were collected. We detected 28 labral tears (24 anterior, 2 anterolateral, 1 lateral and 1 posterolateral). An abnormal labral-chondral transitional zone was seen in 9 patients and 4 patients had surface labral fraying. We identified three paralabral cysts. Acetabular cartilage loss was detected in 45 and femoral cartilage loss in 9 patients. An abnormal anterior femoral head and neck junction was present in 18 hips and fibrocystic change in 8. Acetabular retroversion was present in 11 hips. 63 sets of patient notes were reviewed, of which 49 were in-patients with abnormal MDCT arthrogram findings. Surgical correlation was available in 27 patients. There was a discrepancy between the findings of a labral tear in one patient (false negative, 90% sensitivity and 100% specificity) and the presence of acetabular cartilage loss (88% sensitivity and 100% specificity) and femoral cartilage loss (94% sensitivity and 100% specificity) in three patients. MDCT arthrography affords accurate detection of intra-articular hip pathology.

Radiofrequency ablation of chondroblastoma: procedure technique, clinical and MR imaging follow up of four cases.

PURPOSE: The aim of this study is to describe the procedure technique, clinical and imaging outcomes of patients treated with radiofrequency ablation for chondroblastoma. MATERIALS AND METHODS: Four patients (female/male, 3:1; mean age, 13 years; age range; 9-16 years) underwent the procedure. All had pre-operative magnetic resonance imaging (MRI) and symptomatic, biopsy-proven chondroblastomas (two proximal femur, two proximal tibia). The lesion size ranged from 1.5 to 2.5 cm in maximal dimension (mean size, 1.8 cm). Bone access was gained with a Bonopty biopsy needle system (mean number of radiofrequency needle placements, 5; mean ablation time, 31 min). RESULTS: Clinical and MRI follow-up was available in all cases (mean, 12.25 months; range, 5-18 months). All patients reported resolution of symptoms at 2-6 weeks post ablation. At their most recent clinical follow-up, three patients remained completely asymptomatic with full return to normal activities and one patient had minor local discomfort (different pain pattern) that was not limiting activity. All four patients' follow-up MRI studies demonstrated resolution of the oedema pattern around the lesion and temporal evolution of the internal signal characteristics with fatty replacement. CONCLUSION: Radiofrequency ablation for chondroblastoma provides an alternative to surgical curettage, and we have demonstrated both a clinical improvement in symptoms and the follow-up MRI appearances.

Imaging strategy for detecting lung metastases at presentation in patients with soft tissue sarcomas.

PURPOSE: To identify the risk of lung metastases at the time of diagnosis in patients with soft tissue sarcomas (STS) and to establish the optimum imaging strategy for the diagnosis of these metastases and whether this affects outcome. MATERIALS AND METHODS: A retrospective review of an orthopaedic oncology database identified 1170 patients with newly diagnosed STS during a 7.5-year period (1996-2004). The patient demographics, tumour type, size, depth, histology grade and presence of metastatic disease at presentation were studied. The chest radiograph (CXR)/computed tomography of the chest (CT chest) findings, performed as part of the initial staging study, were available in all patients. We estimated the efficacy of CXR in identifying pulmonary metastatic disease compared with CT chest and whether this affected patient survival. RESULTS: The incidence of metastases at diagnosis was 10% (116 patients), 8.3% (96 patients) had lung metastases on chest CT and 1.7% (20 patients) had metastases elsewhere. The risk of having lung metastases at diagnosis was 11.8% in high grade tumours, 7% in intermediate grade and 1.2% in low grade tumours. CXR alone detected 2/3 of all lung metastases. The positive predictive value of the CXR was 93.3%, the negative predictive value 96.7%, the sensitivity 60.8% and the specificity 99.6%. The accuracy was 96.9%. CT overestimated metastases in 4% with a sensitivity of 100%, specificity of 99.6% and accuracy of 99.6%. Median survival of patients with lung metastases at diagnosis was 11 months and there was no significant difference in survival between those who had metastases detected on CXR or purely on CT. DISCUSSION: We recommend that all patients with a suspected STS should have a CXR at presentation, prior to histological diagnosis. CT of the chest should then be performed in those patients with an abnormality on the presentation CXR and routinely in those patients who have large, deep seated or high/intermediate grade tumours and in certain histological subtypes where the incidence of lung metastases at diagnosis is known to be high. In our experience, this strategy will detect 93% of all chest metastases. With current treatment strategies for metastases, outcome is not likely to be affected by any delay in diagnosis.