DETECTION OF CHOLANGIOCARCINOMA IN PRIMARY SCLEROSING CHOLANGITIS BY POSITRON-EMISSION-TOMOGRAPHY

Primary sclerosing cholangitis (PSC) predisposes to cholangiocarcinoma (CC), which usually is widespread in the liver at the time of the dia gnosis and which has a median survival of approximately 6 months. Posi tron emission tomography (PET) is a noninvasive scanning method that a llows the assessment of metabolism in vive by means of positron-emitti ng radiolabeled tracers. [F-18] Fluoro-2-deoxy-D-glucose (FDG) is a gl ucose analogue that accumulates in various malignant tumors because of their high glucose metabolic rates. The purpose of the study was to d evelop a PET method to detect small CC tumors in patients with PSC, PE T scanning of the liver was performed after intravenous injection of 2 00 MBq FDG in 9 patients with PSC, 6 patients with PSC + CC, and 5 con trols. The scanning was performed at successive time intervals for a t otal of 90 minutes with simultaneous successive arterial blood samplin g for radioactivity concentration determination. In each of the PSC CC patients, 2 to 7 ''hot spots'' were seen, with volumes of 1.0 to 45 mL (median, 4.4 mL). There were no hot spots in the two other patient groups. The localization of hot spots was confirmed by single-blind e valuation. Data were analyzed by the Gjedde-Patlak plot, yielding valu es of the net metabolic clearance of FDG, K [mL min(-1) 100 mL(-1) tis sue]. In the CC hot spots, maximum K values were 1.59 to 4.17 (median, 2.34; n = 6); in the reference liver tissues of these patients, K val ues were 0.40 to 0.69 (median, 0.49); in PSC patients, they were 0.23 to 0.53 (median, 0.36); and in controls, they were 0.20 to 0.34 (media n, 0.31). The difference between K in CC hot spots and the other group s was statistically significant (P < .001). We conclude that FDG-PET s eems to be able to detect small CC tumors and may be useful in the the rapeutic management of PSC.