Negative predictive value of CT for occult fractures of the hip and pelvis with imaging follow-up

An Umbrella Review and Updated Meta-Analysis of Imaging Modalities in Occult Scaphoid and Hip and Femoral Fractures

Background: Occult fractures may cause multiple morbidities. If occult fractures were detected earlier, complications may be preventable. This umbrella review and updated meta-analysis will aim to evaluate the use of imaging modalities in detecting occult scaphoid and hip fractures. Methods: The protocol for this study is available in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42024525388). The literature search started and ended on 17 March 2024. We searched seven academic databases: MEDLINE, Cochrane Library, Pubmed, Science Direct, Google Scholar, WHO International Clinical Trials Registry Platform, and The Joanna Briggs Institute (JBI) database. The meta-analysis was conducted with the STATA program using the "midas" command. Results: There are four systematic reviews evaluating occult hip and femoral fractures with 6174 patients and two reviews evaluating occult scaphoid fractures with 1355 patients. The prevalence of occult scaphoid fracture and occult hip and femoral fractures is 23.87% (95% CI 18.25-29.49) and 44.8% (95% CI 39.38-51.4), respectively. Magnetic resonance imaging (MRI) had the best posterior probability of positive likelihood ratio (LR+) with 95% and 96% and negative likelihood ratio (LR-) with 0.15% and 1% for both occult scaphoid and hip fractures, respectively, assuming a 25% baseline. MRI could both confirm and exclude occult hip fractures while it can only confirm occult scaphoid fractures. Bone scans are inappropriate for either type of occult fractures The level of evidence for occult scaphoid fracture is weak while it is suggestive for occult hip fractures. Conclusion: The findings strengthen the use of MRI after an initially negative radiograph fracture for occult hip and femoral fractures, with a CT scan as a viable second option.

Quantitative evaluation of bone marrow characteristics in occult and subtle rib fractures by spectral CT

PURPOSE

The present study aimed to determine whether the water content change in the medullary cavity of occult rib fractures by spectral computed tomography (CT).

METHODS

The material decomposition (MD) images were reconstructed using the water-hydroxyapatite basis material pairs from spectral CT. The water contents of the medullary cavity in subtle or occult rib fractures and the symmetrical sites of the contralateral ribs were measured, and their difference was calculated. The absolute value of the water content difference was compared to patients without trauma. An independent samples t-test was adopted to compare the consistency of the water content in the medullary cavity of the normal ribs. Intergroup and pairwise comparisons were applied to the difference in water content among the subtle/occult fractures and normal ribs, followed by receiver operating characteristic curve calculations. p < 0.05 was considered to have a statistically significant difference.

RESULTS

A total of 100 subtle fractures, 47 occult fractures, and 96 pairs of normal ribs were included in this study. The water content of the medullary cavity in the subtle and occult fractures was both higher than that in their symmetrical sites with the difference value of 31.06 ± 15.03 mg/cm3 and 27.83 ± 11.40 mg/cm3, respectively. These difference values between the subtle and occult fractures were not statistically significant (p = 0.497). For the normal ribs, the bilateral water contents were not statistically different (p > 0.05) with a difference value of 8.05 ± 6.13 mg/cm3. The increased water content of fractured ribs was higher than that of normal ribs (p < 0.001). According to the classification based on whether the ribs were fractured, the area under the curve was 0.94.

CONCLUSIONS

The water content measured on MD images in spectral CT in the medullary cavity increased as a response to subtle/occult rib fractures.

Traumatic bone marrow lesions in dual-energy computed tomography

Traumatic bone marrow lesions (TBMLs) are considered to represent a range of concealed bone injuries, including haemorrhage, infarction, and localised oedema caused by trabecular microfracture occurring in the cancellous bone. If TBMLs are not managed timeously, they potentially cause a series of complications that can lead to irreversible morbidity and prolonged recovery time. This article reviews interesting image findings of bone marrow lesions in dual-energy computed tomography (DECT). In addition to combining the benefits of traditional CT imaging, DECT also reveals and identifies various structures using diverse attenuation characteristics of different radiographic spectra. Therefore, DECT has the capacity to detect TBMLs, which have traditionally been diagnosed using MRI. Through evaluating DECT virtual non-calcium maps, the detection of TBMLs is rendered easier and more efficient in some acute accidents.

Musculoskeletal Trauma and Infection

MR is often the most definitive imaging for assessment of musculoskeletal trauma and infection. Although it is not possible to address all the intricacies of these complex topics in a single article, this review will attempt to provide a useful toolbox of skills by discussing several common clinical scenarios faced by emergency radiologists in interpretation of adult trauma and infection. These scenarios include MR assessment of hip and pelvic fracture, traumatic soft tissue injuries, septic arthritis, soft tissue infection, and osteomyelitis.