We treated 75 patients with symptomatic cholesterol gallstones by dissolving the stones with methyl tert-butyl ether (MTBE) instilled into the gallbladder through a percutaneous transhepatic catheter. The MTBE was continuously infused and aspirated manually four to six times a minute, for an average of five hours per day for one to three days; the treatment was monitored by fluoroscopy. The placement of the catheter and the administration of MTBE caused few side effects or complications, and treatment did not have to be stopped in any patient for this reason. In 72 patients there was complete dissolution of stones or more than 95 percent dissolution. Among 21 patients who were completely free of stones after treatment, 4 had recurrence of stone formation 6 to 16 months later. The other 51 patients had residual debris, which spontaneously cleared completely in 15 patients within 6 to 35 months; only 7 with persisting debris have had symptoms. Five of the initial 6 patients treated, but only 1 of the next 69 patients, have required surgery during follow-up periods of 6 to 42 months. We conclude that the dissolution of gallstones by MTBE delivered through a percutaneous transhepatic catheter is a useful alternative to surgery in selected patients with symptomatic cholesterol stones. Further study will be necessary to establish the long-term effectiveness of this treatment and its appropriate role in the management of the various types of gallstones.

Ultrasound and computed tomography have had an enormous impact on the imaging procedures used in the detection of tumors of the parathyroids, pancreas, and adrenals. Ultrasound is now the examination of choice in localizing parathyroid adenomas in the neck prior to cervical exploration or after unsuccessful exploration. Its role as a screening test in patients without biochemical confirmation of hyperparathyroidism awaits further study. Computed tomography is useful in identifying mediastinal parathyroid adenomas in patients who have had unsuccessful neck explorations and islet-cell tumors of the pancreas if they are sufficiently large (greater than 2 cm). Angiography remains the most accurate method of localizing insulinomas prior to surgery. Computed tomography scanning has become the procedure of choice in localizing adrenal tumors and has sufficient sensitivity to be used as a screening test in patients without biochemical confirmation of an adrenal abnormality.