PURPOSE: To describe how a robust implementation of a radial 3D gradient-echo sequence with stack-of-stars sampling can be achieved, to review the imaging properties of radial acquisitions, and to share the experience from more than 5000 clinical patient scans. MATERIALS AND METHODS: A radial stack-of-stars sequence was implemented and installed on 9 clinical MR systems operating at 1.5 and 3 Tesla. Protocols were designed for various applications in which motion artifacts frequently pose a problem with conventional Cartesian techniques. Radial scans were added to routine examinations without selection of specific patient cohorts. RESULTS: Radial acquisitions show significantly lower sensitivity to motion and allow examinations during free breathing. Elimination of breath-holding reduces failure rates for non-compliant patients and enables imaging at higher resolution. Residual artifacts appear as streaks, which are easy to identify and rarely obscure diagnostic information. The improved robustness comes at the expense of longer scan durations, the requirement for fat suppression, and the nonexistence of a time-to-center value. Care needs to be taken during the configuration of receive coils. CONCLUSION: Routine clinical use of radial stack-of-stars sequences is feasible with current MR systems and may serve as substitute for conventional fat-suppressed T1-weighted protocols in applications where motion is likely to degrade the image quality.
Artifacts ; Cohort Studies ; Humans ; Respiration

Mycophenolate mofetil (MMF)-related colitis is one of the common causes of afebrile diarrhea in transplant patients. Pathologic diagnosis of MMF-related colitis is difficult because microscopic findings of MMF effects resemble those of graft-versus-host disease, inflammatory bowel disease and ischemic colitis. However, if diagnosed, MMF-induced colitis can be markedly improved by discontinuing the drug. A 70-year-old man having a history of transplantation presented with a one month history of afebrile diarrhea. Colonoscopy revealed patchy erosions. The colonoscopic biopsy specimen showed not only crypt disarray with degenerated crypts and scattered epithelial cell apoptosis, but also stromal inflammatory cell infiltration. A review of his medical records showed that he had been taking immunosuppressive drugs including MMF since his heart transplantation 6 years prior. The histologic findings of colonic mucosa were consistent with MMF-related colitis. After discontinuing MMF, the diarrhea quickly resolved and has not recurred for 10 months.
Aged ; Apoptosis ; Biopsy ; Colitis ; Colitis, Ischemic ; Colon ; Colonoscopy ; Diarrhea ; Epithelial Cells ; Graft vs Host Disease ; Heart Transplantation ; Humans ; Inflammatory Bowel Diseases ; Medical Records ; Mucous Membrane ; Mycophenolic Acid ; Transplants