Efficacy of three-dimensional fast imaging with steady precession dynamic MR imaging in evaluating pancreatic ductal adenocarcinoma

Preoperative vascular evaluation with computed tomography and magnetic resonance imaging for pancreatic cancer: a meta-analysis

OBJECTIVES

Vascular invasion (VI) is the most important factor in assessing operability for pancreatic cancer. The accuracy of preoperative vascular staging with computed tomography (CT) and magnetic resonance imaging (MRI) was examined using meta-analysis.

METHODS

Published articles in pancreatic cancer comparing diagnostic accuracy of CT with MRI for VI confirmed on histology were searched from MEDLINE, EMBASE and ISI Web of Science databases. Pooled sensitivity, specificity, likelihood ratio, summary receiver operating characteristic (SROC) curve and area under curve (AUC) were analysed by SPSS 13.0 and Revmen 5.1.

RESULTS

Eight studies (n = 296) met the inclusion criteria. The pooled sensitivity of CT and MRI in diagnosing VI was 71% (95% CI, 64-78) and 67% (95% CI, 59-74), pooled specificity 92% (95% CI, 89-95) and 94% (95% CI, 91-96), positive likelihood ratio 6.33 (95% CI, 4.51-8.87) and 6.58 (95% CI, 4.62-9.37), negative likelihood ratio 0.34 (95% CI, 0.27-0.43) and 0.38 (95% CI, 0.30-0.47), and AUCs 0.87 and 0.76 (p = 0.63), respectively. There was no significant difference between CT and MRI for preoperative diagnosis of VI. Subgroup analysis of 4 studies (n = 143) showed no significant difference between CT and MRI in preoperative diagnosis of venous or arterial invasion (p = 0.73 and p = 0.81, respectively). When CT was compared with MRA in 3 studies (n = 110), again there was no significant difference for preoperative staging of VI (p = 0.54).

CONCLUSIONS

Both CT and MRI are underreporting vascular invasion preoperatively in pancreatic cancer. MRA does not add any additional information on vascular staging when compared with CT and MRI.

Diagnostic value of the delayed phase image for iso-attenuating pancreatic carcinomas in the pancreatic parenchymal phase on multidetector computed tomography

PURPOSE

To assess the value of the delayed phase (DP) in pancreatic carcinomas which appear iso-attenuating in the pancreatic parenchymal phase (PPP).

MATERIALS AND METHODS

Fifty-seven preoperative MDCT studies of pancreatic carcinomas were retrospectively reviewed. The size of the tumors, and the Hounsfield unit (HU) of the tumors and pancreatic parenchyma were measured. The tumor-to-pancreas contrast (TPC: |HU [tumor]-HU [normal pancreas]|) was calculated.

RESULTS

Eight cases (14.0%) showed iso-attenuation and 49 showed hypo-attenuation in the PPP. The DP images revealed seven of eight (87.5%) iso-attenuating tumors to be hyper-attenuating. The size of iso-attenuating tumors was smaller than that of hypo-attenuating tumors (mean+/-S.D.: 12.4+/-4.8mm vs. 30.3+/-9.0mm, p<0.0001). In hypo-attenuating tumors, TPC in the PPP (60.2+/-24.6 HU) was higher than those in the portal venous phase (PVP, 40.5+/-23.0 HU, p<0.0001) and DP (18.3+/-11.8 HU, p<0.0001). In contrast, in iso-attenuating tumors, TPC in the DP (26.0+/-4.9 HU) was higher than those in the PPP (9.2+/-3.7 HU, p=0.0003) and PVP (7.1+/-4.7 HU, p=0.001) phases.

CONCLUSION

The DP image is helpful in depicting small iso-attenuating pancreatic carcinomas as slightly hyper-attenuating tumors.