Evaluation of iliopsoas compartment disorders by computed tomography

Iliopsoas compartment lesion frequently goes undiagnosed at clinical presentation. Therefore, even delayed diagnosis may depend on radiographic techniques. Computed tomography (CT) can play an important role in the identification and localization of these lesions. This report concerns the experience of using CT to evaluate the iliopsoas compartment disorder.

Retrospective review of CT scans for 42 patients who had abnormalities of the iliopsoas compartment revealed that inflammation was responsible in 20, hemorrhage in 8, and tumor in 14 patients. Diagnoses were proven by surgery or biopsy/aspiration in all cases except in five cases whose CT findings correlated with their clinical pictures. A comparison was made among the surgical data, the CT and plain abdominal films. In addition, a comparative evaluation of CT features was also made.

By using a hypodense area for the diagnosis of psoas abscess, the sensitivity, specificity and accuracy of CT were 100%, 77%, and 88%, respectively. By using a diffuse involvement of the entire muscle for the diagnosis of hemorrhage, the sensitivity, specificity and accuracy of CT were 63%, 62%, and 62% respectively. By using a bone destruction for the diagnosis of tumors, the sensitivity, specificity and accuracy of CT were 79%, 39%, and 69%, respectively. Evaluation of the iliopsoas compartment lesions was 91% sensitive by CT and 40% sensitive by plain X-ray film.

It is difficult to differentiate iliopsoas abscesses, hematomas and neoplasms without knowing the clinical history. However, when coupled with percutaneous aspiration biopsy, CT has proved to be an effective, rapid means to diagnose and guide the therapy of psoas lesions.