[Opportunities of delayed densitometry of "late (fixed) contrast" as a test for tumors in residual mediastinal lesion in primary mediastinal lymphosarcoma after polychemotherapy]. / Vozmozhnosti sposoba otsrochennoi densitometrii "pozdnego (fiksirovannogo) kontrasta", primeniaemogo v kachestve testa opukholi v ostatochnom obrazovanii sredosteniia pri pervichnykh mediastinal'nykh limfosarkomakh posle okonchaniia polikhimioterapii.

AIM: To clarify the potential of delayed densitometry of late (fixed) contrast in differentiation between tumor and fibrosis in residual mediastinal lesion (RML). MATERIAL AND METHODS: Computed tomography (computed tomograph of the third generation COMATOM CR-3 made in Germany, SIEMENS) has examined 12 patients with mediastinal lymphosarcomas after polychemotherapy. All of them had a RML 3 to 6 cm in diameter. RESULTS: CT has detected 8 cases of the tumor and 4 cases of fibrosis. The criteria of the tumor were the following: increased RML density shortly after the contrast medium introduction and 30 min after urographine introduction (p < 0.01); RML density 30 min after introduction of contrast medium was higher than above the aorta (p < 0.01). Fibrosis in RML was stated if RML density before, at the high of concentration and after introduction of the contrast medium was the same (p > 0.01); aortic density was significantly higher of RML density at the height of the contrast (p < 0.01). CONCLUSION: The above method differentiates the tumor with fibrosis in RML with maximal probability. This facilitates further choice of therapeutic policy in secondary resistant form of primary mediastinal lymphosarcoma.