Dual Phases Angiography Of Pancreas With Multidector-row Computed Tomography

[Objective] (a) To measure the frequency of visualization of pancreatic vessels with thin-slice maximum intensity projection (TSMIP), maximum intensity projection (MIP) and volume rendering (VR) computed tomography angiogrphy (CTA) techniques using multidetector-row CT (MDCT), (b)To compare the advantages of different techniques, (c)To discuss the optimal scanning method of MDCTA of pancreas.[Materials and Methods] Dual-phase CTA using a Siemens Sensation16 scanner was performed in 40 cases meeting the including and excluding criteria. Acquisition of arterial phase scan was initiated 4 second after reaching enhancement of celiac artery up to 1 00Hu as measured by a bolus tracking technique. Acquisition of portal venous phase was performed 55-65 second after initiate contrast medium injection, (collimation =0.75mm, table speed= 12mm, reconstruction interval = 0.7mm,pitch=l). Post processing was performed on Siemens Wizard Workstation. CTA of pancreatic vesselswere made using the TSMIP, MIP and VR techniques. Two experienced radiologists evaluated together and recorded the frequency and degree of visualization of celiac, hepatic, spleenic, gastroduodenal, superior mesenteric, anterior- and posterior-superior pancreaticoduodenal, inferior pancreaticoduodenal arteries; portal, spleenic, superior mesenteric, gastrocolic trunk, right superior colic, anterior- and posterior- superior pancreaticoduodenal vein. The interval between every two techniques was one week. The differences in the frequency and degree of visualization between two techniques were statistically analyzed by the %2 test. The difference in the degree analyzed by Rank Sum Test.[Results] The indirect pancreatic feeding arteries, PV, SMV, SV, RGEVwere all seen in each technique. In TSMIP, MIP, VR, visualization rates of PSPDA were 92.5%, 91.5%, 67.5% respectively,- ASPDA, 95%, 92.5%, 80%; IDPA, 75%, 67.5%, 57.5%; RSCV, 100%, 87.5%, 80%; PSPDV, 92.5%, 65%, 40%; ASPDV, 92.5%, 62.5%, 45%. There was significant difference in visualization rates of PSPDA, ASPDA, IDPA, RSCV, ASPDV, PSPDV using either the MIP or VRT. So did IDPA, PSPDV, ASPDV using either the MIP or VR. TSMIP is superior to MIP in the degree of visualization of GDA, LGA, HPA, the direct feeding arteries, portosystem, and superior to Vein GDA, LGA, HPA, RSCV, PSPDV, ASPDV, and RGEV. MIP was superior to VR in direct feeding arteries, RGEV, PSPDV, ASPDV, and RSCV. On the contrary, VR was superior to MIP in PV, SMV, SV, and GCT.[Conclusion] Conspicuity of pancreatic CTA can be gained using MDCTwith optimal scanning time. The selection of reconstruction is influenced by the difference of enhancement between the target vessel and the surrounding. If the difference is larger, VR is better than MIP; and if the difference is smaller, MIP is better than VR. TSMIP is superior to MIP and VR in the manifestation of small vessels of peripancreas.