ABSTRACT
Outstanding results have been achieved with magnetic resonance (MR) angiography, which has become competitive with conventional angiography as a vascular imaging technique. With the advances in gradient technology and the capability of imaging vessels in a single breath hold, one can track an intravenous bolus of paramagnetic contrast agent and evaluate the entire mesenteric circulation. Use of a breath-hold technique obviates the problem of motion artifact. Use of targeted maximum-intensity projection images from the three-dimensional (3D) volume data allows evaluation of the vascular anatomy at different phases (arterial and venous) of contrast enhancement. MR angiography performed with a contrast-enhanced breath-hold fat-suppressed 3D technique allows visualization of the superior mesenteric vessels, celiac artery, and portal vein in healthy subjects. Pathologic conditions of the mesenteric vessels that can be identified with this technique include stenosis or occlusion of the superior mesenteric artery, celiac artery aneurysm, thrombosis of the superior mesenteric vein, portal hypertension with varices, and vascular invasion by pancreatic carcinoma.
Subject(s)
Image Enhancement/instrumentation , Image Processing, Computer-Assisted/instrumentation , Magnetic Resonance Angiography/instrumentation , Mesenteric Vascular Occlusion/diagnosis , Adult , Aged , Equipment Design , Female , Humans , Male , Mesenteric Arteries/pathology , Mesenteric Vascular Occlusion/etiology , Mesenteric Veins/pathology , Middle Aged , Reference Values , Sensitivity and SpecificityABSTRACT
We describe a case of a single pulmonary vascular malformation studied with a new contrast-enhanced three-dimensional MRA technique. Images provided the interventional radiologist with a pre-embolization road map from which information regarding the number and size of feeding and draining vessels was obtained accurately and noninvasively.
Subject(s)
Arteriovenous Malformations/diagnosis , Magnetic Resonance Angiography/methods , Pulmonary Artery/abnormalities , Radiographic Image Enhancement/methods , Adult , Arteriovenous Malformations/therapy , Contrast Media/administration & dosage , Diagnosis, Differential , Embolization, Therapeutic , Humans , Male , Sensitivity and SpecificityABSTRACT
To evaluate the mesenteric circulation with magnetic resonance (MR) angiography, the authors examined 16 individuals (12 patients, four volunteers) with a gadolinium-enhanced, breath-hold, fat-saturated, multiecho, three-dimensional, gradient-echo sequence. Twenty examinations were performed. Grades of 3 or 4 (on a five-point scale [4 = best seen, 0 = not seen]) were applicable to 17 (85%) of 20 MR angiograms obtained in superior mesenteric artery trunks, 15 (75%) in celiac arteries, five (25%) in inferior mesenteric arteries; 15 (75%) of first-order branching, 12 (60%) of second-order branching, and 10 (50%) of third-order branching; 17 (85%) in superior mesenteric veins; and 17 (85%) in portal veins. MR angiography with this technique depicted the mesenteric arterial and venous circulation and the portal vein with excellent resolution in a short time.
Subject(s)
Magnetic Resonance Angiography/methods , Mesenteric Arteries/anatomy & histology , Mesenteric Veins/anatomy & histology , Portal Vein/anatomy & histology , Adult , Aged , Celiac Artery/anatomy & histology , Celiac Artery/pathology , Contrast Media , Drug Combinations , Fasting , Female , Gadolinium , Gadolinium DTPA , Humans , Male , Meglumine , Mesenteric Arteries/pathology , Mesenteric Vascular Occlusion/diagnosis , Mesenteric Veins/pathology , Middle Aged , Organometallic Compounds , Pentetic Acid/analogs & derivatives , Portal Vein/pathologyABSTRACT
1,2-Dimyristoyloxypropane-3-thiophospho(1D-1-myo-inositol) (D-thio-DMPI) was synthesized as a substrate for the continuous spectrophotometric assay of phosphatidylinositol-specific phospholipase C (PI-PLC) from Bacillus cereus. Release of thio-diglyceride is followed by a coupled reaction with 4,4'-dithiopyridine to produce a chromophore, 4-thiopyridine, measured by its absorption at 324 nm. Sonicated vesicles of D-thio-DMPI gave sigmoidal Michaelis-Menten kinetics with PI-PLC as a function of bulk concentration of substrate (Hill plot: Vmax = 132 mumol min-1 mg-1, apparent Km = 0.115 mM, h = 1.8). Addition of dimyristoyl phosphatidylcholine (DMPC) or dimyristoyl phosphatidylmethanol to vesicles of D-thio-DMPI resulted in an initial increase in rate followed by a decrease at higher concentrations of non-substrate lipid. Binding of PI-PLC to vesicles of DMPC with 10 mol% of N-dansyl phosphatidylethanolamine was demonstrated by fluorescence resonance energy transfer from tryptophan in the enzyme to the dansyl lipid probe.
