Colleen Mary Costelloe MD, Presenter: Nothing to Disclose

William A. Murphy MD, Abstract Co-Author: Nothing to Disclose

John E. Madewell MD, Abstract Co-Author: Nothing to Disclose

Tamara Miner Haygood MD, PhD, Abstract Co-Author: Nothing to Disclose

Rajendra Kumar MD, Abstract Co-Author: Nothing to Disclose

Kevin William McEnery MD, Abstract Co-Author: Medical Advisory Board, Research In Motion Limited

R. Jason Stafford PhD, DABR, Abstract Co-Author: Consultant, BioTex, Inc, Houston, TX

Robyn Harrell, Abstract Co-Author: Nothing to Disclose

Roland Bassett, Abstract Co-Author: Nothing to Disclose

00030490-DMT et al, Abstract Co-Author: Nothing to Disclose

Nephrogenic systemic fibrosis has been associated with intravenous gadolinium MR contrast agents in renal-impaired patients. ACR usage guidelines suggest nephrology referral for GFR<30 mL/min/1.73 m2 and that the lowest beneficial dose (half dose suggested) be administered if risk-benefit assessment indicates the need for contrast in patients with GFR<60 mL/min/1.73 m2. This retrospective study investigates the effect of half versus full dose on the perceived contrast-enhanced conspicuity of the same bone or soft tissue musculoskeletal (MSK) lesion in the same patient on MR exams that differed in time.

Included were patients with MSK or spinal MRI from 6/07 to 6/08 with 2 exams at the same field strength but 1 at full and 1 at reduced (40-60%) contrast dose. Five MSK radiologists, blinded to dose, independently compared the same specific lesion per study. Each reader decided if the lesion was less conspicuous on one exam (tallied as low dose study) of the pair; by what degree (mild, moderate, severe). No readings were consensus and interval irradiation was excluded. The study was IRB approved.

Thirty-four patients were included with 17 lesions in bone and 17 in soft tissue. Change in size occurred in 8 lesions (6 increase, 2 decrease), defined as a 20% difference. Twenty-seven pairs of exams were scanned at 1.5T and 7 at 3.0T. Thirty-two pairs used fat suppression, 2 pairs did not. Sixty-seven exams used Magnevist and 1 Ominiscan. Correct answers were summed, divided by total conspicuous exams, and compared to 50% by exact binomial test. There was no evidence that 55% (37/67) significantly differed from 50%, p=0.46. Most conspicuity differences were rated as mild. The proportion of correct answers by reader was assessed by exact binomial test. Correct identification of the low dose exam was not significantly different than 50%. Repeated measures logistic regression showed no evidence that tissue type, systemic therapy, change in size or field strength was associated with correct choice of the reduced dose exam p=0.63, p=0.69, p=0.65 and p=0.70. 

Readers were not able to accurately perceive a difference in lesion enhancement when full and half dose MRI examinations of the same lesion were directly compared.

Reduced (half) dose contrast enhancement of MSK lesions may be equivalent to full dose enhancement, allowing for cost savings and greater patient safety.

Costelloe, C, Murphy, W, Madewell, J, Haygood, T, Kumar, R, McEnery, K, Stafford, R, Harrell, R, Bassett, R, et al, 0, The Effect of Half Dose Intravenous Gadolinium MR Contrast on the Conspicuity of Bone and Soft Tissue Lesions.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8002071.html