MEDIASTINAL TUBERCULOUS LYMPHADENITIS - MR-IMAGING APPEARANCE WITH CLINICOPATHOLOGICAL CORRELATION

OBJECTIVE. The purpose of our study was to determine the MR imaging ap pearance of mediastinal tuberculous lymphadenitis and to compare these findings with clinical and pathologic findings, MATERIALS AND METHODS . MR images of 23 consecutive patients with mediastinal tuberculous ly mphadenitis were retrospectively analyzed with regard to homogeneity, signal intensity, and enhancement of diseased nodes after injection of contrast material (n = 19), and the imaging findings were grouped by patterns and correlated with clinical signs or symptoms and with patho logic (n = 9) findings. RESULTS. Three imaging patterns of mediastinal tuberculous lymphadenitis (113 nodes) were seen on MR images. In six patients, nodes (type 1, n = 25) were relatively homogeneous and hyper intense to muscle on both T1- and T2-weighted images and enhanced homo geneously after injection of contrast material. The patients had mild (n = 2) or no (n = 4) constitutional symptoms, The nodes corresponded pathologically to tuberculous granulomas without or with minimal necro sis. In 14 patients, nodes (type 2, n = 71) were inhomogeneous with a strong peripheral enhancement after injection of contrast material. En hancing areas were of intermediate intensity on T1-weighted images and hypointense on TS-weighted images, and corresponded pathologically to peripheral granulation tissue within the nodes. Unenhanced areas were relatively hypointense on T1-weighted images and markedly hyperintens e on T2-weighted images, and corresponded pathologically to central ca seation or liquefaction necrosis within the nodes. All but one patient with type 2 nodes had moderate to severe clinical signs and symptoms. In the remaining three patients, nodes (type 3, n = 17)were homogeneo usly hypointense on both T1- and TP-weighted images and did not enhanc e after injection of contrast material, No patient with type 3 nodes h ad clinical signs or symptoms. The nodes corresponded pathologically t o fibrocalcified nodes. CONCLUSION. The most common MR imaging appeara nce of mediastinal tuberculous lymphadenitis was as inhomogeneous node s with marked hyperintensity on T2-weighted images and peripheral enha ncement after injection of contrast material. This typical MR imaging appearance was mostly seen in severely symptomatic patients and was du e to caseation necrosis of the tuberculous nodes.