HEPATOSPLENIC FUNGAL DISEASE - DIAGNOSTIC-ACCURACY AND SPECTRUM OF APPEARANCES ON MR-IMAGING

OBJECTIVE. We describe our 6-year experience in the prospective examin ation of patients with suspected hepatosplenic fungal disease to show the diagnostic accuracy of MR imaging and the spectrum of appearances on MR images. SUBJECTS AND METHODS. All patients who underwent MR exam ination for suspected hepatosplenic fungal disease from January 1990 t o January 1997 in three university institutions were included in the s tudy. Patients presented with persistent fever or no response to antib acterial antibiotics. Patients were grouped as acute, subacute treated , and chronic treated, according to the duration of their symptoms. Pa tients with 2 weeks or fewer of possible infection were acute presenta tion, patients on antifungal therapy longer than 2 weeks but shorter t han 3 months were subacute treated presentation, and patients on antif ungal therapy for 3 months or longer or who had completed antifungal t herapy and had a history of hepatosplenic fungal disease were chronic treated presentation. MR studies were prospectively interpreted for th e presence of hepatosplenic fungal lesions. The appearances of fungal lesions in patients in each category were determined. The sensitivity, specificity, positive predictive value, negative predictive value, an d accuracy for detecting lesions in patients with acute presentation w ere also determined. RESULTS. Sixty-nine patients were included in the study, MR imaging revealed signs consistent with hepatosplenic fungal lesions in 22 (32%) of 69 patients and no demonstration of hepatosple nic lesions in 47 (68%) of 69 patients. In the 60 patients with acute presentation, MR imaging in 13 patients revealed hepatosplenic lesions that were interpreted as fungal disease. True-positive lesions were p resent in 11 of these 13 patients. These lesions measured less than 1 cm in diameter and were best shown as well-defined high-signal-intensi ty foci on T2-weighted images. The remaining two of the 13 patients ha d false-positive lesions; one was shown to have tuberculosis, and the other had graft-versus-host disease, For acute presentation, MR sensit ivity was 100%, specificity was 96%, positive predictive value was 85% , negative predictive value was 100%, and accuracy was 97%, In the fiv e patients with subacute presentation, lesions were present that measu red less than 1 cm in diameter and were best shown as mildly hyperinte nse on T1-weighted images. A perilesional ring nearly void of signal i ntensity was seen on unenhanced and gadolinium-enhanced T1-weighted im ages in all five patients. The four patients with chronic healed lesio ns all had lesions that were 1-3 cm in diameter with irregular, angula r polygonal margins, These lesions, which were best shown on images ob tained immediately after gadolinium administration, appeared as region s of diminished enhancement with no perilesional changes. CONCLUSION. MR imaging has high diagnostic accuracy for the diagnosis of acute hep atosplenic fungal disease, Patients with acute, subacute treated, and chronic healed presentations may have lesions that can be distinguishe d by their MR appearances.