MR imaging of apparent small-bowel perfusion for diagnosing mesenteric ischemia: feasibility study.

The purpose of this study, which was approved by the institutional review board, was to assess the differentiation of individuals with from those without mesenteric ischemia. All subjects provided written informed consent. Six healthy volunteers and six patients with documented chronic mesenteric ischemia underwent magnetic resonance (MR) imaging with and without oral caloric stimulation. After intravenous administration of paramagnetic contrast material, signal intensity values of the small-bowel wall were measured up to 130 seconds after contrast material injection. Volunteers and patients, respectively, had maximum enhancement of the bowel wall between 70 and 85 seconds after contrast material administration that amounted to 269% and 267% without and 425% and 333% with caloric stimulation. MR imaging assessment of small-bowel perfusion is possible and seems feasible for differentiating individuals with from those without mesenteric ischemia.

Combined small and large bowel MR imaging in patients with Crohn's disease: a feasibility study.

MRI of the small bowel is a new method for the assessment of inflammatory bowel diseases. However, inflammatory bowel disease can affect both the small and large bowel. Therefore, our goal was to assess the feasibility of displaying the small bowel and colon simultaneously by MR imaging. Eighteen patients with inflammatory bowel disease were studied. For small bowel distension, patients ingested a solution containing mannitol and locust bean gum. Furthermore, the colon was rectally filled with water. MR examinations were performed on a 1.5-T system. Before and after intravenous gadolinium administration, a T1w data set was collected. All patients underwent conventional colonoscopy as a standard of reference. The oral ingestion and the rectal application of water allowed an assessment of the small bowel and colon in all patients. By means of MRI (endoscopy), 19 (13) inflamed bowel segments in the colon and terminal ileum were detected. Furthermore, eight additional inflammatory lesions in the jejunum and proximal ileum that had not been endoscopically accessible were found by MRI. The simultaneous display of the small and large bowel by MRI is feasible. Major advantages of the proposed MR concept are related to its non-invasive character as well as to the potential to visualize parts of the small bowel that cannot be reached by endoscopy.

Optimization of oral contrast agents for MR imaging of the small bowel.

Effect on small-bowel distention of additives to water as contrast agents for magnetic resonance (MR) imaging was assessed. Oral contrast agents included water and water in combination with mannitol, a bulk fiber laxative, locust bean gum, and a combination of mannitol and locust bean gum. Filling of the small bowel was quantified on coronal images obtained with two-dimensional true fast imaging with steady-state precession sequence; bowel diameters were measured. Ingestion of water with locust bean gum and mannitol provided the best distention of the small bowel. MR imaging of the small bowel with oral administration of water can be improved with addition of osmotic and nonosmotic substances that lead to decreased water resorption.

Interventional management of aortic dissection.

BACKGROUND: Modern high-resolution imaging techniques have provided new insights into the pathogenesis of aortic dissection during recent years. Distinct pathologic entities or potential precursors of classic false-lumen aortic dissection such as intramural hematoma or penetrating atherosclerotic ulcer have been identified. As a result, a novel classification according to Svensson used in addition to the standard differentiation according to DeBakey or Stanford has been introduced. Due to improved diagnostic imaging, preoperative mortality has decreased but mortality remains substantial (up to 1.4% per hour within the first 2 days) related to complications of aortic dissection such as aortic rupture, bleeding, pericardial tamponade, critical branch vessel ischemia, multiorgan failure, and myocardial infarction. EXAMINATIONS: Transesophageal echocardiography, angiography, magnetic resonance imaging or computed tomography as well as intravascular ultrasound are used for a complete vascular "staging" of patients with aortic dissection after initial stabilization (with or without surgery). New catheter-based interventional techniques have been developed to improve the poor prognosis of aortic dissection: 1 Percutaneous balloon fenestration (PTF) of the intimal flap improves perfusion in case of bowel, limb, or renal ischemia. 2. Aortic stent-graft placement allows for occlusion of the intimal entry tear by implantation of a membrane-covered, self-expanding stent-graft to initiate progressive thrombus formation within the false lumen. Compared to the traditional surgical approaches, both techniques have a low complication rate. The development of these techniques may help to further improve to decrease patients' morbidity and mortality.

Assessment of ventricular function with single breath-hold real-time steady-state free precession cine MR imaging.

OBJECTIVE: The aim of our study was to evaluate whether a recently developed real-time steady-state free precession (trueFISP) cine sequence could be used to assess left ventricular function in a single breath-hold. CONCLUSION: Using real-time trueFISP permits one to assess left ventricular function in a single breath-hold. The dramatic reduction in data acquisition time does require some compromises. The temporal and spatial resolutions of images obtained with real-time trueFISP were considerably lower than those achieved with segmented trueFISP. Further reduction of the TR or the use of sensitivity encoding could improve temporal resolution and eliminate other limitations of real-time trueFISP.