ABSTRACT
INTRODUCTION: There is an increasing incidence of hip and pelvic fractures with an ageing population. Accurate and timely diagnosis is important in the emergency setting. While magnetic resonance imaging (MRI) is the gold standard, it is a limited resource. Dual energy CT (DECT) is comparable to MRI in detection of bone marrow oedema. Our hospital was the first centre in our country to introduce DECT for occult pelvic fractures. We aimed to describe its utility in occult pelvic fractures since commencement. METHODS: Retrospective study of consecutive pelvic bone CT (conventional or DECT) performed to look for an occult fracture over a 10-month period. Sensitivity and specificity calculated based on clinical and imaging follow-up. ROC study performed where three observers visually interpreted pelvic radiographs, conventional CT and DECT and scored their confidence for an acute fracture from 1 to 5. The null hypothesis was that DECT would not improve observer performance compared with conventional CT. RESULTS: DECT studies were performed on 178 patients of whom 84 (47%) had acute fractures. Sensitivity on audit was 99% and specificity was 100%. ROC analysis showed that, for all observers, the area under curve increased from radiograph to conventional CT to DECT. The difference between conventional CT and DECT was statistically significant for all observers where metal implants were not present. CONCLUSION: DECT improves accuracy compared to conventional CT in the diagnosis of occult pelvic fractures and should be used for this indication when available.
ABSTRACT
BACKGROUND: Features of new bone formation (NBF) are common in tophaceous gout. The aim of this project was to develop a plain radiographic scoring system for NBF in gout. METHODS: Informed by a literature review, scoring systems were tested in 80 individual 1st and 5th metatarsophalangeal joints. Plain radiography scores were compared with computed tomography (CT) measurements of the same joints. The best-performing scoring system was then tested in paired sets of hand and foot radiographs obtained over 2 years from an additional 25 patients. Inter-reader reproducibility was assessed using intraclass correlation coefficients (ICC). NBF scores were correlated with plain radiographic erosion scores (using the gout-modified Sharp-van der Heijde system). RESULTS: Following a series of structured reviews of plain radiographs and scoring exercises, a semi-quantitative scoring system for sclerosis and spur was developed. In the individual joint analysis, the inter-observer ICC (95% CI) was 0.84 (0.76-0.89) for sclerosis and 0.81 (0.72-0.87) for spur. Plain radiographic sclerosis and spur scores correlated with CT measurements (r = 0.65-0.74, P < 0.001 for all analyses). For the hand and foot radiograph sets, the inter-observer ICC (95% CI) was 0.94 (0.90-0.98) for sclerosis score and 0.76 (0.65-0.84) for spur score. Sclerosis and spur scores correlated highly with plain radiographic erosion scores (r = 0.87 and 0.71 respectively), but not with change in erosion scores over 2 years (r = -0.04-0.15). CONCLUSION: A semi-quantitative plain radiographic scoring method for the assessment of NBF in gout is feasible, valid, and reproducible. This method may facilitate consistent measurement of NBF in gout.
