ULTRAFAST MAGNETIC-RESONANCE-IMAGING IMPROVES THE STAGING OF PANCREATIC TUMORS

Objective This prospective study was undertaken to evaluate the accura cy of a noninvasive ''all-in-one'' staging method in predicting surgic al resectability in patients with pancreatic or periampullary tumors. Summary Background Data Despite progress in imaging techniques, accura te staging and correct prediction of resectability remains one of the chief problems in the management of pancreatic tumors. Staging algorit hms designed to separate operable from inoperable patients to save the latter an unnecessary laparotomy are becoming increasingly complex, e xpensive, time-consuming, invasive, and not without risks for the pati ent. Methods Between August 1996 and February 1997, 58 consecutive pat ients referred for operation of a pancreatic or periampullary tumor we re examined clinically and by 5 staging methods: 1) percutaneous ultra sonography (US); 2) ultrafast magnetic resonance imaging (UMRI); 3) du al-phase helical computed tomography (CT); 4) selective visceral angio graphy; and 5) endoscopic cholangiopancreatography (ERCP). The assessm ent of resectability by each procedure was verified by surgical explor ation and histologic examination. Results The study comprised 40 male and 18 female patients with a median age of 63 years; Thirty-five lesi ons were located in the pancreatic head (60%), 11 in the body (19%), a nd 1 in the tail of the gland (2%); there were 9 tumors of the ampulla (16%) and 2 of the distal common duct (3%). All five staging methods were completed in 36 patients. For reasons ranging from metallic impla nts to contrast medium allergy or because investigations already had b een performed elsewhere, US was completed in 57 (98%), UMRI in 54 (93% ), CT in 49 (84%), angiography in 48 (83%), and ERCP in 49 (84%) of th ese 58 patients. Signs of unrespectability found were vascular involve ment in 22 (38%), extrapancreatic tumor spread in 16 (26%), liver meta stases in 10 (17%), lymph node involvement in 6 (10%), and peritoneal nodules in only 2 patients (3%). These findings were collated with tho se of surgical exploration in 47 patients (81%) and percutaneous biops y in 5 (9%); such invasive verification was deemed unnecessary and the refore unethical in 6 clearly inoperable patients (10%). In assessing the four main signs of unrespectability (extrapancreatic tumor spread, liver metastases, lymph node involvement, and vascular invasion), the overall accuracy of UMRI was 95.7%, 93.5%, 80.4%, as compared to 85.1 %, 87.2%, 76.6% for US and 74.4%, 87.2%, 69.2% for CT. In assessing va scular invasion, the sensitivity, specificity, and overall accuracy of angiography were 42.9%, 100%, and 68.8%, respectively. There were 3 c omplications (12.5%) after 24 resections, 5 in 17 palliative procedure s, and none after 6 explorations only. The hospital stay was 14 days a fter resection, 13 after palliative bypass, and 6 after exploration al one. There was no operative or hospital mortality in these 58 cases. C onclusions Although it is by no means 100% accurate, UMRI is equal or even superior to all other staging methods. It probably will replace m ost of these, because it provides an ''all-in-one'' investigation avoi ding endoscopy, vascular cannulation, allergic reactions, and x-radiat ion. But because even UMRI is not perfect, the final verdict on resect ability of a tumor still will depend on surgical exploration in some c ases.