PICTORIAL ESSAY Multislice CT angiography of mesenteric vessels R. Iannaccone, A. Laghi, R. Passariello Department of Radiological Sciences, University of Rome “La Sapienza”, Policlinico Umberto I, Via Arturo Graf, 40 00137 Rome, Italy Abstract Due to several distinct advantages over conventional angiog- raphy (including minimal invasiveness, lower cost, and lower ionizing radiation exposure for patients and staff), computed tomography (CT) angiography has replaced diag- nostic conventional angiography in several clinical situa- tions. The recent introduction of multislice CT (MSCT) scanners has significantly improved CT angiographic appli- cations, especially in the evaluation of the mesenteric vas- culature. Thin-slice collimation protocols associated with powerful postprocessing procedures allow the display of mesenteric circulation with excellent detail. The purposes of this presentation are (a) to illustrate the imaging technique that can be used to obtain state-of-the-art MSCT angio- graphic images of the mesenteric vasculature, (b) to review the normal anatomy and anatomic variants of mesenteric vessels, and (c) to illustrate some of the potential clinical applications of MSCT angiography of the mesenteric ves- sels. Key words: Computed tomography, multislice—Computed tomography, angiography—Computed tomography, tech- nique—Mesenteric vessels, anatomy—Mesenteric vessels, abnormalities The development of multislice spiral computed tomography (MSCT) has represented the major improvement in CT tech- nology since the introduction of spiral CT scanning. Indeed, this new technology provides several important advantages as compared with single-slice CT. First, MSCT offers faster acquisition times [1–3]. This translates to a remarkable in- crease of the so-called volume coverage speed with the capability of examining larger anatomic regions in a single breath-hold and with reduced motion and/or respiratory ar- tifacts. Second, MSCT provides routine acquisition of thin- slice collimation protocols with a substantial increase in longitudinal spatial resolution [1–3]. This guarantees almost isotropic voxels with better image quality and optimal data- sets for excellent three-dimensional (3D) reconstructions [1–3]. Third, MSCT offers the possibility to better optimize contrast material administration [1]. Indeed, with MSCT scanners, it is much easier to separate different phases of contrast enhancement (e.g., hepatic arterial phase and portal venous phase). Overall, these advantages have completely revolutionized CT angiography. In particular, CT angiographic applications to the mesenteric vasculature have been significantly im- proved, opening a wide range of clinical applications [4 – 6]. The purposes of this presentation are (a) to illustrate the imaging technique that can be used to obtain state-of-the-art MSCT angiographic images of the mesenteric vasculature, (b) to review the normal anatomy and anatomic variants of mesenteric vessels, and (c) to illustrate some of the potential clinical applications of MSCT angiography of the mesenteric vessels. Imaging technique There are several technical parameters of MSCT angiogra- phy that must be considered to obtain images of the mesen- teric vasculature of optimal diagnostic quality. First, contrast material administration has to be carefully optimized, considering timing, amount, and injection rate. Due to the fact that each patient has a different circulatory time, there is a substantial risk of scanning the patient too early (with an insufficient amount of contrast material in the vessels) or too late (with opacification of venous vessels during the arterial phase) when a fixed delay time is used (usually 25 or 30 s as start time for the arterial phase). Therefore, we usually use the test bolus technique in which a minibolus (20 mL) of contrast material is injected and a series of single-level CT scans at low dose are acquired every 2 s at the level of the hepatic hilum. The time of maximal opacification of the abdominal aorta is used as the start time for the arterial phase (usually between 18 and Correspondence to: R. Iannaccone; email: riannaccone@tiscali.it Abdominal Imaging © Springer-Verlag New York, Inc. 2004 Published online: 14 January 2004 Abdom Imaging (2004) 29:146 –152 DOI: 10.1007/s00261-003-0096-9