CT and US of the pancreas

Prospective evaluation of ultrasound and colour duplex imaging for the assessment of surgical resectability of pancreatic tumours

BACKGROUND

This study was performed to evaluate colour duplex imaging (CDI) for the assessment of resectability of pancreatic tumours (PTs).

METHOD

From October 1998 to December 2001, 182 patients consecutively having surgery for a PT were enrolled in this prospective study. Extension of the tumour to large blood vessels and retroperitoneum, the detection of liver metastases, enlarged lymph nodes and peritoneal carcinomatosis were defined as criteria for assessment. The patients were grouped into three classes of resectability: US-TU 1 = resectable/potentially curable, US-TU 2 = questionably resectable/curable, and US-TU 3 = non-resectable/not curable. CDI was performed by five different examiners. Results were compared with intra-operative findings.

RESULTS

Using CDI, we classified 85 (46.7%) tumours as resectable, 64 (35.2%) as non-resectable, and 33 (18.1%) as questionably resectable. Overall, 46.2% ( n=84) were found to be resectable, and 53.8% ( n=98) to be non-resectable, intra-operatively. A correlation between CDI classification and intra-operative findings was found in 138 of 149 cases (92.6%) (sensitivity 88.4%, specificity 96.3%). With regard to the complete oncological status (local extension, metastases, lymph-node staging and peritoneal carcinomatosis), a sensitivity of 77.2% and specificity of 95.7% were found. Non-correlated findings were likely attributed to missing small liver metastases, peritoneal carcinomatosis without ascites, and on difficulties in the assessment of enlarged lymph nodes concerning tumour infiltration.

CONCLUSION

The use of CDI in evaluation of PTs may provide valuable pre-operative assessment of surgical resectability and may be performed in the clinical setting.

Radiologic features of cystic, endocrine and other pancreatic neoplasms

This article presents imaging features of cystic, endocrine and other pancreatic neoplasms. Microcystic adenoma which is composed of small cysts (<2 cm), its macrocystic subgroup contains solitary cyst. Multiple cysts larger than 2 cm are associated with mucinous cystic neoplasm. Swiss cheese appearence with central calcification is characteristic for microcystic adenomas. Septal and mural enhancement as well as larger size (>2 cm) are accounted for mucinous cystic neoplasms, its variant along pancreatic duct is ductectatic mucinous cystic neolasm. Endocrine tumors of pancreas are hypervascular and can be depicted on early dynamic enhanced crosssectional imaging modalities or on angiography when they are <1 cm. Pancreatic metastases and lymphomas are rare neoplasms which should also be included in differential diagnosis for pancreatic masses.

CT criteria for venous invasion in patients with pancreatic head carcinoma

The purpose of the study was to evaluate CT criteria for venous invasion in patients with potentially resectable carcinoma of the pancreatic head, with surgical and histopathological correlation. In 113 patients evaluated with spiral CT for suspected pancreatic head carcinoma, several CT criteria for venous invasion were scored prospectively for the portal vein (PV) and the superior mesenteric vein (SMV): length of tumour contact with PV/SMV (0 mm, < 5 mm, > 5 mm); circumferential involvement of the vein (0 degree, 0-90 degrees, 90-180 degrees, > 180 degrees); degree of stenosis; irregularity of the vessel margin; and tumour convexity towards vessel. 65 patients underwent surgery. Pancreatic head carcinoma was proven and pathology of the vascular margin was obtained in 50 of these patients. CT findings for single and combined criteria were correlated with pathology in these 50 patients, 30 of whom showed venous ingrowth. Invasion was found in all cases with SMV narrowing (n = 7), PV contour involvement > 90 degrees (n = 6), PV narrowing (n = 5) and PV wall irregularity (n = 3). The vascular ingrowth rate was 88% (15/17) for tumour concavity towards the PV or SMV. Poor predictors of ingrowth were length of tumour contact with PV > 5 mm (78% ingrowth, 14/18) and contour involvement of the SMV > 90 degrees (83% ingrowth, 10/12). Absence of vascular ingrowth could not be predicted in 100%. In conclusion, CT criteria can predict a high risk of invasion in potentially resectable tumours. Narrowing of the SMV and the PV seems the most reliable criterion, as well as circumferential involvement of the PV > 90 degrees. The best combination of criteria was tumour concavity with circumferential involvement > 90 degrees (sensitivity 60% and positive predictive value 90%).

Utility of abdominal sonography in patients with idiopathic deep vein thrombosis

PURPOSE

Studies have confirmed an association between idiopathic deep vein thrombosis (DVT) and malignant tumors. We assessed the usefulness of routine abdominal sonography in patients with idiopathic DVT to detect malignant tumors and other relevant findings.

METHODS

We retrospectively analyzed abdominal sonograms and records from 135 consecutive patients with confirmed idiopathic DVT and interviewed patients and their physicians during the follow-up period (mean, 30 months). Malignancy and other clinically relevant findings determined by sonography were tabulated, and the cost of each malignancy detected by abdominal sonography in this study was calculated.

RESULTS

Malignant tumors were found in 14 patients (10%), 7 by routine abdominal sonography, 3 by other means during hospitalization, and 4 during the follow-up period. Other clinically relevant findings detected by routine abdominal sonography were found in 33 patients (24%). The estimated cost of discovering malignancy by using screening abdominal sonography was approximately US$3,000/malignancy.

CONCLUSIONS

Abdominal sonography was useful in detecting a variety of clinically relevant findings in addition to half of the malignant tumors found in our study.