Purpose: To evaluate a new technique for imaging the pancreas (spiral
hydro-CT) based on a combination of pharmacological intestinal paralys
is and water distension of the stomach and duodenum with specific refe
rence to tumor detection rate, differentiation of malignant versus ben
ign tumors, differential diagnosis and assessment of tumor resectabili
ty. Material and methods: In an open prospective study, 151 patients w
ith a suspected pancreatic neoplasm based on clinical, laboratory or o
ther imaging data were examined between May 94 and October 95. Our new
ly developed Hydro-CT methodology included intravenous injection of 40
mg N-butylscopolaminium bromide (Buscopan) for intestinal paralysis,
gastric and duodenal wall distension by oral administration of an aver
age of 1.51 warm tap water, 30 degrees RAO patient positioning, an ind
ividualized contrast injection technique as determined beforehand by t
ime-to-peak measurement in the portal vein and thin-slice spiral CT (3
mm increment, 6 mm table feed and 3 mm secondary reconstruction). A d
etailed evaluation form was used to assess (1) tumor detection rate, (
2) differentiation of malignant versus benign disease, (3) differentia
l diagnosis, and (4) accuracy of assessment of resectability by identi
fication of infiltration into adjacent organs and vessel structures re
levant for resectability such as splenic, superior mesenteric, portal
vein and celiac trunk, superior mesenteric, splenic and hepatic arteri
es. As the gold standard for positive tumor detection surgery and micr
oscopic diagnosis were used, and for negative tumor detection an event
-free survival of 6 months. Results: Almost all examinations were well
tolerated. In only 4% was on-site administration of a gastric tube re
quired because of vomiting. In 2% of the patients a slight allergic re
action to the contrast medium was seen. The prevalence of a pancreatic
neoplasm was 38%. In tumor detection Hydro-CT reached an overall accu
racy of 97.4% with a sensitivity of 100% and a specificity of 95.9%. I
n the differentiation of benign versus malignant disease Hydro-CT reac
hed an overall accuracy of 89.7% with a sensitivity of 92.5% and a spe
cificity of 83.3%. The prevalence of a pancreatic carcinoma was 24%; 4
% other malignant tumors were found (distal common bile duct carcinoma
, cystadenocarcinoma). Fifty-eight patients underwent surgical explora
tion. In those assessment of resectability reached an overall accuracy
of 95% with a sensitivity of 90.5% and specificity of 100%. Conclusio
n: The new technique of Hydro-CT based on thin slice and spiral method
ology, including pharmacological intestinal paralysis and water disten
sion, results in a high tumor detection rate and increases sensitivity
and specificity of tumor differential diagnosis and of assessment of
resectability.