Ultrasound, computed tomography and magnetic resonance in the investigation of iliopsoas compartment disease

: The authors reviewed the results of imaging studies performed in 30 patients with diseases involving the iliopsoas compartment (IPC) to assess the role of Ultrasound (US), Computed Tomography (CT) and Magnetic Resonance (MR) in the investigation of these deep seated and often clinically undetectable lesions. 16 (53%) patients had histologically proven benign or malignant IPC tumours with bacterial infection in 12 (40%) and haemorrhage into the IPC in 2 (7%). US correctly detected iliopsoas pathology in only 9 of 17 cases (53%) and was satisfactory only in limited situations, such as abscess formation in children and haemorrhage in haemophiliacs. CT was much more accurate (16/17, 94%) than US and correctly diagnosed 7 cases overlooked on US, while also offering greater information in 5 cases where both studies were abnormal. CT was particularly helpful for the detection of both abscess formation and calcification within mass lesion. MR was accurate in all 9 cases imaged, and was very helpful in the assessment of associated vertebral, disc or spinal canal involvement by tumour or infection. A review of the literature, and the results of this study, suggest that CT and MR often have complementary roles where IPC disease is known or suspected. The accuracy of US in IPC disease is limited, preferably being followed by CT or MR imaging.