Objective: The primary objective of this trial was to compare the parastomal hernia rates 1 year after the construction of an end colostomy by 3 surgical techniques: cruciate incision, circular incision in the fascia and using prophylactic mesh. Secondary objectives were evaluation of postoperative complications, readmissions/reoperations, and risk factors for parastomal hernia. Summary of Background Data: Colostomy construction techniques have been explored with the aim to improve function and reduce stoma complications, but parastomal herniation is frequent with an incidence of approximately 50%. Methods: A randomized, multicenter trial was performed in 3 hospitals in Sweden and Denmark; all patients scheduled to receive an end colostomy were asked to participate. Parastomal hernia within 12 months was determined by computed tomography of the abdomen in prone position and by clinical assessment. Complications, readmissions, reoperations, and risk factors were also assessed. Results: Two hundred nine patients were randomized to 1 of the 3 arms of the study. Patient demographics were similar in all 3 groups. Assessment of parastomal hernia was possible in 185 patients. The risk ratio (95% confidence interval) for parastomal hernia was 1.25 (0.83; 1.88), and 1.22 (0.81; 1.84) between cruciate versus circular and cruciate versus mesh groups, respectively. There were no statistically significant differences between the groups with regard to parastomal hernia rate. Age and body mass index were found to be associated with development of a parastomal hernia. Conclusion: We found no significant differences in the rates of parastomal hernia within 12 months of index surgery between the 3 surgical techniques of colostomy construction.

In the last decade contrast-enhanced magnetic resonance angiography (CE-MRA) has gained wide acceptance as a valuable tool in the diagnostic work-up of patients with peripheral arterial disease. This review presents current concepts in peripheral CE-MRA with emphasis on MRI technique and contrast agents. Peripheral CE-MRA is defined as an MR angiogram of the arteries from the aortic bifurcation to the feet. Advantages of CE-MRA include minimal invasiveness and lack of ionizing radiation. The basic technique employed for peripheral CE-MRA is the bolus-chase method. With this method a paramagnetic MRI contrast agent is injected intravenously and T1-weighted images are acquired in the subsequent arterial first-pass phase. In order to achieve high quality MR angiograms without interfering venous contamination or artifacts, a number of factors need to be taken into account. This includes magnetic field strength of the MRI system, receiver coil configuration, use of parallel imaging, contrast bolus timing technique, and k-space filling strategies. Furthermore, it is possible to optimize peripheral CE-MRA using venous compression techniques, hybrid scan protocols, time-resolved imaging, and steady-state MRA. Gadolinium(Gd)-based contrast agents are used for CE-MRA of the peripheral arteries. Extracellular Gd agents have a pharmacokinetic profile similar to iodinated contrast media. Accordingly, these agents are employed for first-pass MRA. Blood-pool Gd-based agents are characterized by prolonged intravascular stay, due to macromolecular structure or protein binding. These agents can be used for first-pass, as well as steady-state MRA. Some Gd-based contrast agents with low thermodynamic stability have been linked to development of nephrogenic systemic fibrosis in patients with severe renal insufficiency. Using optimized technique and a stable MRI contrast agent, peripheral CE-MRA is a safe procedure with diagnostic accuracy close to that of conventional catheter X-ray angiography.

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