Contrast-enhanced three-dimensional magnetic resonance angiography of the splanchnic vasculature before and after caloric stimulation. Original investigation.
OBJECTIVE
To develop a comprehensive noninvasive magnetic resonance angiography (MRA) strategy for the morphologic and functional assessment of the splanchnic arteries, based on a combination of breath-held contrast-enhanced 3D MRA and segmented k-space 2D phase-contrast acquisitions acquired before and after caloric stimulation.


METHODS
Ten healthy volunteers were examined twice: once in the fasting state (6 hours with no food intake) and a second time following caloric stimulation with a standard 475-kcal meal. Flow in the superior mesenteric artery (SMA) and vein (SMV) was quantitated using a 2D breath-held, segmented k-space phase-contrast (PC) acquisition in a plane perpendicular to the axis of the vessels, while vascular morphology was displayed with a contrast-enhanced 3D MRA acquisition consisting of 44 contiguous 2-mm sections, acquired in apnea (28 seconds). For comparative analysis, the splanchnic vasculature was divided into 11 segments and evaluated on a 2-point scale (cannot exclude pathology, can exclude pathology).


RESULTS
Flow volume in the SMA increased from 2.3 ml/min/kg (+/- 0.9 ml/min kg) to 7.3 ml/min kg (+/- 4.7 ml/min kg) following caloric stimulation (P < 0.05). Flow in the SMV exceeded flow in the SMA and increased from 3.4 ml/min/kg (+/- 0.3 ml/min kg) to 9.1 ml/min/kg (+/- 4.8 ml/min/kg) following stimulation. Flow volume of SMV correlated better with SMA flow after stimulation. Caloric stimulation significantly improved visualization of the splanchnic arterial vasculature (P < 0.05). Only 5 of 110 evaluated arterial segments (4.5%) remained inadequately seen to exclude vascular pathology.


CONCLUSIONS
Magnetic resonance imaging offers a comprehensive assessment of the splanchnic arterial vasculature based on 3D display of vessel morphology and analysis of flow function. While the most relevant proximal vessel segments are visible even under fasting conditions, caloric stimulation enhances visualization of small vessels.
Institute of Diagnostic Radiology, University Hospital Zürich, Switzerland. debatin@dmr.usz.ch
T F
TF
Hany
M
M
Schmidt
A W
AW
Schoenenberger
J F
JF
Debatin
D000328:Adult; D001783:Blood Flow Velocity; D003287:Contrast Media; D002149:Energy Intake; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008643:Mesentery / Q000098:blood supply; D012016:Reference Values; D013152:Splanchnic Circulation; D013157:Splenic Artery / Q000033:anatomy & histology* / Q000502:physiology; D013162:Splenic Vein / Q000033:anatomy & histology* / Q000502:physiology
D003287:Contrast Media; D019786:Gadolinium DTPA