A Factor Increasing Venous Contamination on Bolus Chase Three-dimensional Magnetic Resonance Imaging: Charcot Neuroarthropathy

Background: The study aimed to evaluate the ratio of venous contamination in diabetic cases without foot lesion, with foot lesion and with Charcot neuroarthropathy (CN). Materials and Methods: Bolus-chase three-dimensional magnetic resonance (MR) of 396 extremities of patients with diabetes mellitus was analyzed, retrospectively. Extremities were divided into three groups as follows: diabetic patients without foot ulcer or Charcot arthropathy (Group A), patients with diabetic foot ulcers (Group B) and patients with CN accompanying diabetic foot ulcers (Group C). Furthermore, amount of venous contamination classified as no venous contamination, mild venous contamination, and severe venous contamination. The relationship between venous contamination and extremity groups was investigated. Results: Severe venous contamination was seen in Group A, Group B, and Group C, 5.6%, 15.2%, and 34.1%, respectively. Statistically significant difference was seen between groups with regard to venous contamination. Conclusion: Venous contamination following bolus chase MR was higher in patients with CN.

High Resolution Contrast-Enhanced MR Angiography in the Evaluation of Rabbit Carotid Artery

This study compared a high resolution contrast-enhanced MR angiography (MRA) sequence to conventional contrast-enhanced MRA sequence for imaging of rabbit carotid artery. Fifteen rabbits underwent an evaluation using both high resolution contrast-enhanced MRA sequence and conventional contrast-enhanced MRA sequence. Siemens 1.5 Tesla Magnetom Vision system was utilized. The parameters of high resolution sequence were: TR/TE= 6.2/2.0 msec, flip angle 25°, matrix 130×512, pixel size 0.96×0.49 mm, partition thickness 1.58 mm, acquisition time 24 sec. The parameters of conventional sequence were: TR/TE=3.8/1.4 msec, flip angle 35°, matrix 110×256, pixel size 1.48×1.02 mm, partition thickness 2mm, acquisition time 10 sec. Maximum intensity projection (MIP) images were created. Both original single slices and MIP images were used for image quality evaluation. Contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), distinctness of artery edge, and venous contamination were analyzed for both techniques. Higher average CNR and SNR were obtained with high resolution contrast-enhanced MRA, compared to average CNR and SNR with conventional contrast-enhanced MRA. The differences were statistically significant (P<0.01). The artery edge with high resolution method was more distinct than conventional method. Jugular venous contamination was found in five of 15 cases with high resolution contrast-enhanced MRA and in four of 15 cases with conventional contrast-enhanced MRA. High resolution contrast-enhanced MRA has significant potential for high quality noninvasive vascular imaging. The image quality with high resolution contrast-enhanced MRA sequence is better than conventional contrast-enhanced MRA sequence.

Neuroradiological Diagnostic Tools: New MRI Perspectives

MR angiography5,17 is traditionally divided into “non-contrast enhanced” (NCE MRA) and “contrast-enhanced” (CE MRA) techniques. Contrast-enhanced techniques were initially developed to solve some of the problems encountered with non-contrast-enhanced methods, namely the long examination times, pulsatile flow artefacts, saturation when the mean blood flow is slow or when the imaging slice is parallel to the vessel, the characteristic problems of time of flight (TOF) acquisitions, and the need to define a priori beforehand the velocity sensitivity for phase contrast (PC) acquisitions. Currently used contrast-enhanced techniques 7,8,15,18 are based on the acquisition of 3D gradient-echo sequences synchronized at the first passage of contrast medium by different strategies (detection of a test bolus injection, automated triggering, fluoroscopic imaging). Basically, contrast medium is administered to counteract saturation induced by slow blood flow or flow directed parallel to the imaging slice. Contrast medium serves to obtain a “static” image of vascular structures with acquisitions times ranging from a few seconds to 1–2 minutes. To avoid venous contamination, different methods have been used to collect data (centric-approach, elliptical-centric phase encoding order, etc.) in an attempt to record first the information relating to low spatial frequencies (contrast data) with respect to high spatial frequencies (detail and contour data).

Fatal Cardiovascular Collapse during Ethanol Sclerotherapy of a Venous Malformation

We report a case of fatal cardiovascular collapse that occurred during Ethanol sclerotherapy of a venous malformation in a 21-year-old woman. The malformation was located on the anterior part of the thigh. Fifty ml of a mixture of Ethanol, Ethibloc and Lipiodol containing 35 ml of Ethanol (0.52 ml / kg) were injected under fluoroscopy. A major drop in arterial pressure was recorded after release of the tourniquet placed at the thigh root. The patient died after four hours of intensive cardiac reanimation. Her blood alcohol level was 0.4 g/l one hour after the end of the intervention. The cardiac toxicity of ethanol depends more on the potential acute venous contamination than on the blood alcohol concentration. The currently admitted “safety limit” of 1 ml/kg of bodyweight for ethanol sclerotherapy of venous malformations is certainly unsafe and must be redefined.