Cardiac MR imaging of nonischemic cardiomyopathies: imaging protocols and spectra of appearances.

Recent technologic advances in cardiac magnetic resonance (MR) imaging have resulted in images with high spatial and temporal resolution and excellent myocardial tissue characterization. Cardiac MR is a valuable imaging technique for detection and assessment of the morphology and functional characteristics of the nonischemic cardiomyopathy. It has gained acceptance as a standalone imaging modality that can provide further information beyond the capabilities of traditional modalities such as echocardiography and angiography. Black-blood fast spin-echo MR images allow morphologic assessment of the heart with high spatial resolution, while T2-weighted MR images can depict acute myocardial edema. Contrast material-enhanced images can depict and be used to quantify myocardial edema, infiltration, and fibrosis. This review presents recommended cardiac MR protocols for and the spectrum of imaging appearances of the nonischemic cardiomyopathies.

Contrast-induced nephrotoxicity: possible synergistic effect of stress hyperglycemia.

OBJECTIVE: Oxidative stress on the renal tubules has been implicated as a mechanism of injury in both stress hyperglycemia and contrast-induced nephrotoxicity. The purpose of this study was to determine whether the combination of these effects has a synergistic effect on accentuating renal tubular apoptosis and therefore increasing the risk of contrast-induced nephrotoxicity. MATERIALS AND METHODS: Dog kidney cells were incubated with 5- and 30-mmol/L glucose solutions and no glucose and then exposed for 2 hours to three types of contrast media-high osmolar (370 mg I/mL), low osmolar (300 mg I/mL), and isoosmolar (320 mg I/mL)-and a mannitol control solution. In an identical experiment, each group of cells was pretreated with an antioxidant-N-acetylcysteine or taurine-to evaluate the protective effect, if any. Apoptosis was assessed with fluorescence-activated cell sorter flow cytometry. RESULTS: The high-osmolar contrast medium was associated with significantly elevated levels of apoptosis compared with the mannitol control (percentage apoptosis, 27.98 +/- 1.08 vs 6.19 +/- 0.771; p < 0.001). This effect was less pronounced after incubation with the low-osmolar agent but was still significant (percentage apoptosis, 20.19 +/- 0.3665 vs 6.19 +/- 0.771; p < 0.001). The isosmolar agent did not have a significant effect. Both the high- and low-osmolar contrast media coupled with hyperglycemia (30-mmol/L glucose) were associated with a significantly increased level of apoptosis. In all contrast medium groups, taurine had a greater protective effect on attenuation of cell apoptosis than did N-acetylcysteine. CONCLUSION: The combination of contrast medium and an elevated glucose level has a synergistic effect on apoptosis. Taurine may be a more effective prophylactic antioxidant than the currently advocated antioxidant, N-acetylcysteine.

Iodinated contrast media alter immune responses in pro-inflammatory states.

BACKGROUND: Hypertonic saline causes a transient elevation of blood osmolality and has been shown to alter cellular inflammatory responses in pro-inflammatory states. Intravascular administration of iodine contrast media also causes a transient elevation of blood osmolarity. PURPOSE: To investigate the effect of iodine contrast media on leukocyte-endothelial interaction in vivo using intravital microscopy. MATERIAL AND METHODS: Male Sprague-Dawley rats (n=36) were randomized into six groups and were treated with: saline, high osmolar contrast medium, low osmolar contrast medium, and endotoxin alone and in combination with the high and low osmolar contrast media. The effect on leukocyte-endothelial interaction in the post-mesenteric venules was observed using the technique of intravital microscopy. The sequence of leukocyte rolling velocity, leukocyte-endothelial cell adherence, and transmigration was recorded and analyzed at 10 min intervals to a maximum of 120 min. RESULTS: Endotoxin significantly decreased the rolling velocity and increased the adherence and transmigration of leukocytes in a time-dependent manner. Both types of iodine contrast media attenuated this pro-inflammatory response to endotoxin. This effect began between 60 and 70 min after the onset of the experiment. CONCLUSION: Hyperosmolar and lower osmolar iodine contrast media attenuate the pro-inflammatory leukocyte-endothelial response to endotoxin in vivo.

Cardiac tumors: optimal cardiac MR sequences and spectrum of imaging appearances.

OBJECTIVE: This article reviews the optimal cardiac MRI sequences for and the spectrum of imaging appearances of cardiac tumors. CONCLUSION: Recent technologic advances in cardiac MRI have resulted in the rapid acquisition of images of the heart with high spatial and temporal resolution and excellent myocardial tissue characterization. Cardiac MRI provides optimal assessment of the location, functional characteristics, and soft-tissue features of cardiac tumors, allowing accurate differentiation of benign and malignant lesions.

Two weeks taurine supplementation reverses endothelial dysfunction in young male type 1 diabetics.

Type 1 diabetics have a well-recognised risk of accelerated cardiovascular disease. Even in the absence of clinical signs there are detectable abnormalities of conduit vessel function. Our group has previously reported reversal of endothelial dysfunction in diabetics with pravastatin. In young asymptomatic smokers, taurine supplementation has a beneficial impact on macrovascular function, assessed by FMD, and shows an up-regulation of nitric oxide from monocyte-endothelial cell interactions. We hypothesise that taurine supplementation reverses early endothelial abnormalities in young male type 1 diabetics, as assessed by applanation tonometry, brachial artery ultrasound and laser Doppler fluximetry. Asymptomatic, male diabetics (n=9) were scanned prior to treatment and then randomised in a double-blind cross-over fashion to receive either 2 weeks placebo or taurine. Control patients (n=10) underwent a baseline scan. Assessed diabetics had detectable, statistically significant abnormalities when compared with controls, in both arterial stiffness (augmentation index) and brachial artery reactivity (FMD). Both of these parameters were returned to control levels with 2 weeks taurine supplementation. In conclusion, 2 weeks taurine supplementation reverses early, detectable conduit vessel abnormalities in young male diabetics. This may have important implications in the long-term treatment of diabetic patients and their subsequent progression towards atherosclerotic disease.

Aortic plaque rupture in the setting of acute lower limb ischemia.

Acute aortic plaque rupture is an uncommon cause of acute lower limb ischemia. The authors report sequence computed tomographic imaging of a distal aortic plaque rupture in a young man with bilateral lower limb complications. Clinical awareness, prompt recognition and imaging, and appropriate treatment of this uncommon condition are necessary to improve patient outcomes.

Idiopathic lymphocytic pleuritis: radiographic and high-resolution CT appearances and changes in response to therapy in two adults.

Inflammatory conditions of the pleura characterized by a predominantly lymphocytic infiltrate are described in several disorders. The commonest underlying aetiologies include tuberculous infection, autoimmune disorders (particularly Sjogren's syndrome), and post coronary artery bypass graft surgery. Idiopathic lymphocytic pleuritis (ILP) is a rare form of diffuse pleural inflammation characterized by extensive lymphocytic infiltration for which no cause is found. Radiological descriptions of ILP are limited. We describe the radiographic and high-resolution computed tomography (HRCT) imaging features and response to corticosteroid therapy of ILP in two adults. Both patients presented with bilateral diffuse pleural thickening of >10 mm thickness extending >10 cm craniocaudally with small focal areas of atelectasis. Both cases demonstrated marked improvement in the degree and extent of pleural thickening and rounded atelectasis following corticosteroid therapy. HRCT provided a useful noninvasive method of assessing disease response to therapy.

Primary aortoenteric fistula.

A 78-year-old woman presented with a gastrointestinal hemorrhage and palpable abdominal aortic aneurysm. The computed tomography scan of the abdomen showed a primary aortoenteric fistula. The challenging clinical diagnosis of aortoenteric fistulae and their surgical treatment options are discussed.