Purpose: To evaluate both the quality of CT pancreatoscopy (CTP) obtained with multislice CT (MSCT) and the utility of such an imaging modality for diagnosis of cystic pancreatic lesions.
Methods and Materials: A total of 61 consecutive patients (33 males, 28 females, 20-83 years) who were deemed to represent surgical candidates for various pancreatic diseases prospectively underwent MSCT (Aquilion, Toshiba, Tokyo, Japan). MSCT scans were acquired approximately 45 s after intravenous injection of contrast material(total dosage 100-150 ml, rate 4-5 ml/s) using 120 kV, 200 mAs, and 8 x 1-mm collimation. MSCT data (1-mm slice thickness, 0.5-mm slice interval) were transferred to a workstation (Ziosoft, Tokyo, Japan) to produce CTP images. The following evaluation was performed: 1) Assessment of CTP image quality; 2) Detectability of a communication between the main pancreatic duct and a cystic lesion,which is one of the most important findings to allow differentiation between intraductal papillary mucinous tumors (IPMT) and other pancreatic cystic lesions; and 3) Detectability of an IPMT papillary projection which represents a key finding used in differentiating benign and malignant IPMT. Correlation with conventional endoscopy and/or pathological findings served as a control. CT images were interpreted by two radiologists who were blinded to other radiological findings and clinical data.
Results: Image quality was subjectively graded on a 4-point scale (poor, fair, good, excellent).Of 49 cases with pancreatic ducts >1 mm in diameter, CTP was readily obtained in 46 cases (94 %) with good or excellent image quality. Mean operator time was approximately 5 min. Of 21 patients with a cystic lesion, communication between the main pancreatic duct and the cystic lesion could be assessed with conventional endoscopy and/or surgical specimens in 16 cases. Such communication was confirmed in 11 patients of IPMT. In contrast, no communication was demonstrated in the other five patients, whose pathologic diagnoses were as follows: serous cystadenoma (2), mucinous cystadenoma (1), pseudocyst (1), and retention cyst associated with pancreatic cancer (1). CTP sensitivity, specificity, and accuracy for detection of such communication was 73%, 60%, and 69%, respectively. Of the 11 patients with pathologically proven IPMT, CTP characterized papillary projections >3 mm in 3 out of 4 patients (75%).
Conclusion: CTP represents a feasible imaging modality. Preliminary experience suggests promising results for the diagnosis of cystic pancreatic lesions.