CT Angiography Effective for Assessing Resectability of Pancreatic Adenocarcinoma

A recent study was conducted to evaluate the sensitivity/specificity of multidetector CT angiography (CTA) in the preoperative evaluation of pancreatic adenocarcinoma.

Multidetector CT angiography is helpful in the preoperative evaluation of pancreatic adenocarcinoma and reduces the number of aborted pancreatic resections.

Participants
In this retrospective analysis, 114 patients were placed into 1 of 2 groups; group A patients had definitely resectable lesions according to CTA criteria and group B patients had definitely or questionably unresectable lesions.

Methodology
CT examinations were performed on multidetector row scanners. A bolus-tracking technique and a 150-HU threshold of enhancement was used to determine the timing of the examination. A late arterial-early portal venous phase was performed with a 15-second delay from the threshold and a venous phase with a 40-second delay.

Criteria for unresectability included distant disease, adjacent organ invasion other than the duodenum, and major vascular invasion. Vascular involvement and resectability were graded as follows:

• grade 0 (preserved fat plane or normal pancreas between the lesion and vessel);
• grade 1 (loss of fat plane between the lesion and vessel);
• grade 2 (flattening and/or slight irregularity of 1 side of vessel);
• grade 3 (vessel encasement of at least two-thirds, with altered contour and luminal narrowing);

• grade 4 (major vessel occlusion).

Grades 0 and 1 were considered resectable and grades 2, 3, or 4 were considered probably or definitely unresectable.

Results
93% of lesions in the 88 group A patients were in the pancreatic head or uncinate process; 78 of these patients had complete resections and the other 10 underwent attempted resections subsequently aborted due to invasion of the porta hepatis and gastroduodenal artery, hepatic metastases, positive lymph nodes, or peritoneal implants.

Among the 26 group B patients with lesions considered unresectable at CTA, 85% of lesions were in the pancreatic head; 21 of these patients had surgical confirmation of unresectability based on vascular invasion by CTA.

Surgical confirmation of vascular unresectability was not obtained in the remaining 5 patients due to hepatic or peritoneal metastasis.

Sensitivity and specificity of the detection of resectability was 100% and 72%, respectively.

When the surgical notes and CT findings were discordant, a retrospective evaluation by the experienced pancreatic imagers yielded an overall sensitivity and specificity in the detection of resectability of 100% and 94%, respectively.

The overall sensitivity and specificity in the detection of unresectability was 94% and 100%, respectively, by the pancreatic imagers.

Conclusions
Multidetector CTA reduces the number of aborted pancreatic resections.

Reviewer’s Comments
CTA can be an effective means of assessing resectability of pancreatic adenocarcinoma, which can reduce the incidence of aborted pancreatic resections. A limitation noted in this study was that the separate value of axial images and reconstructions was not investigated.

Author:
John C. Sabatino, MD

Reference:
Zamboni GA, Kruskal JB, et al. Pancreatic Adenocarcinoma: Value of Multidetector CT Angiography in Preoperative Evaluation. Radiology; 2007; 245 (December): 770-778