Contrast-enhanced three-dimensional magnetic resonance angiography of the splanchnic vasculature before and after caloric stimulation - Original investigation

RATIONALE AND OBJECTIVES. 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 calorie 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 (25 seconds). For comparative analysis, the splanchnic vasculature was divided into II 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 how 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 how 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. CONCLUSION. Magnetic resonance imaging offers a comprehensive assessment of the splanchnic arterial vasculature based on 3D display of vessel morphology and analysis of how function. While the most relevant proximal vessel segments are visible even under fasting conditions, caloric stimulation enhances visualization of small vessels.