Dual-Energy CT for Suspected Radiographically Negative Wrist Fractures: A Prospective Diagnostic Test Accuracy Study.

Background Patients with wrist trauma and negative findings on radiographs often undergo additional MRI examinations to assess for radiographically occult fractures. Dual-energy CT may be more readily available than MRI in some settings. Purpose To evaluate the diagnostic test accuracy of dual-energy CT in helping detect bone marrow edema and fracture in participants with wrist trauma and clinical suspicion of a wrist fracture but with negative findings on radiographs. Materials and Methods Adults were prospectively enrolled between January 2018 and November 2018. Wrists were examined with dual-energy CT and MRI, and images were read by four readers who were blinded to clinical information. The presence of bone marrow edema and fracture was rated per bone. The reference standard for bone marrow edema was the combined reading of MRI scans. The reference standard for fracture was a combined reading of MRI and dual-energy CT scans. A fifth radiologist arbitrated results in case of discrepancies. Diagnostic test accuracy was calculated per reader and for readers combined using exact binomial tests. Results Forty-six participants (mean age, 47 years ± 19 [standard deviation]; 24 men [52%]) were enrolled, and 750 bones (50 wrists) were assessed. Dual-energy CT had an average sensitivity of 94% (95% confidence interval [CI]: 80%, 99%; 31 of 33 wrists) and specificity of 65% (95% CI: 38%, 86%; 11 of 17 wrists) in the detection of wrists with bone marrow edema and a sensitivity of 69% (95% CI: 55%, 81%; 36 of 52 bones) and a specificity of 98% (95% CI: 97%, 99%; 682 of 696 bones) in the detection of edema in individual bones. MRI had a sensitivity of 80% (95% CI: 63%, 91%; 28 of 35 wrists) and a specificity of 93% (95% CI: 68%, 100%; 14 of 15 wrists) in helping detect wrists with fractures. Dual-energy CT had a sensitivity of 91% (95% CI: 77%, 98%; 32 of 35 wrists) and a specificity of 87% (95% CI: 60%, 98%; 53 of 60 wrists) in helping detect wrists with fractures. McNemar tests showed no significant differences between MRI and dual-energy CT (P = .07 to >.99) for all readers. Conclusion Dual-energy CT had a high sensitivity and a moderate specificity in the detection of bone marrow edema of the wrist. Dual-energy CT had high sensitivity and specificity in depicting fractures of the wrist in patients with suspected wrist fractures and negative findings on radiographs. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Fukuda in this issue.

Utility of multiple rule out CT screening of high-risk atraumatic patients in an emergency department-a feasibility study.

BACKGROUND: Several large trials have evaluated the effect of CT screening based on specific symptoms, with varying outcomes. Screening of patients with CT based on their prognosis alone has not been examined before. For moderate-to-high risk patients presenting in the emergency department (ED), the potential gain from a CT scan might outweigh the risk of radiation exposure. We hypothesized that an accelerated "multiple rule out" CT screening of moderate-to-high risk patients will detect many clinically unrecognized diagnoses that affect change in treatment. METHOD: Patients ≥ 40 years, triaged as high-risk or moderate-to-high risk according to vital signs, were eligible for inclusion. Patients were scanned with a combined ECG-gated and dual energy CT scan of cerebrum, thorax, and abdomen. The impact of the CT scan on patient diagnosis and treatment was examined prospectively by an expert panel. RESULTS: A total of 100 patients were included in the study, (53% female, mean age 73 years [age range, 43-93]). The scan lead to change in treatment or additional examinations in 37 (37%) patients, of which 24 (24%) were diagnostically significant, change in acute treatment in 11 (11%) cases and previously unrecognized malignant tumors in 10 (10%) cases. The mean size specific radiation dose was 15.9 mSv (± 3.1 mSv). CONCLUSION: Screening with a multi-rule out CT scan of high-risk patients in an ED is feasible and result in discovery of clinically unrecognized diagnoses and malignant tumors, but at the cost of radiation exposure and downstream examinations. The clinical impact of these findings should be evaluated in a larger randomized cohort.

Chronic recurrent multifocal osteomyelitis demonstrated by Tc-99m methylene diphosphonate bone scan.

A 12-year-old Middle Eastern girl presented with abdominal pain, weight loss, and intermittent pain in both thighs. She was initially suspected of Crohn disease, but this diagnosis was excluded after extensive gastromedical evaluation. Plain x-rays of the femora were normal, whereas the initial Tc-99m methylene diphosphonate (MDP) bone scan showed several foci with increased activity in both femurs. MR scan showed excessive periostal inflammatory and mild intramedullary changes in both femurs. A percutaneous bone biopsy demonstrated changes consistent with chronic recurrent multifocal osteomyelitis (CRMO). The patient's symptoms disappeared spontaneously, but reappeared 1.5 years later, which led to a new MDP bone scan that showed normal findings.