Gallstones Detection on Dual-Energy Computerized Tomography-Is It Ready for Real-World Use? A Retrospective Observational Study.

AIMS: The aims of the study are to evaluate the performance of dual-energy computed tomography (DECT) imaging in the detection of noncalcified gallstones (GSs) and to assess its performance relative to transabdominal ultrasound (US) in identifying cholelithiasis. METHOD: This study is a retrospective review of radiology records and images to find all patients who had both US and DECT scans within a 6-month period and were found to have GSs. Patients who did not have GSs on US served as the control group. The CT scans were reviewed by 4 radiologists who did not have access to the US results when assessing the presence or absence of GSs on the DECT scans. In case of any discrepancies among the radiologists, the majority opinion was considered. If there was a split opinion, a fifth reviewer was consulted. The data were analyzed to calculate sensitivity, specificity, positive and negative predictive values, as well as overall accuracy and to evaluate interreader variability. The absolute Hounsfield unit (HU) differences of the GSs and bile were compared between polychromatic (PC), virtual noncontrast (VNC), and virtual monochromatic (VMC) images. RESULTS: Considering at least 3-reader agreement, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were found to be 92%, 96%, 96%, 92%, and 94%, respectively. Individual reader sensitivity varied between 87% and 92%. There was good interobserver agreement with a Fleiss' kappa of 0.76. Quantification of the whole data set showed that no significant difference was observed in the HU values for the stones between the PC images and the VNC images. A significant increase was observed on the 50-keV VMC images compared with the PC and VNC images. In the study group, 17% stones were visualized only on the VNC or/and 50-keV VMC images, and not on the PC images. On quantitative analysis of these cases, there was a significant increase of HU in the VNC images as compared with PC images and a significant decrease of HU in the 50-keV VMC images as compared with PC images. CONCLUSIONS: Low-keV images increase stone-bile contrast. Evaluation of cholelithiasis using VNC and 50-keV VMC images demonstrated a 14% increase in sensitivity relative to conventional CT.

Cervical, Thoracic, and Lumbar Spine Epidural Abscess: Case Report and Literature Review.

We report a case of a spinal epidural abscess (SEA) in a patient without significant risk factors. The patient was treated in an outpatient setting for one week for worsening back pain and subsequently admitted to the hospital for the treatment of sepsis and suspected SEA. An MRI obtained on admission showed an epidural abscess extending from the lower cervical to the upper lumbar region and accompanying paraspinal cervical and psoas abscesses. The patient was successfully treated with antibiotics based on the sensitivity of the surgical cultures received from a needle aspiration of the abscess. SEA has a low incidence; however, the number of cases is consistently rising over the last two decades. The outcome of SEA treatment is related to the duration of the process prior to intuition of the treatment. Patients with no neurological symptoms, or with symptoms lasting less than 36 h, have the best recovery rate. As the typical symptoms of SEA are seen in only 13% of cases, physicians should have a low threshold to order MRI in patients with back pain that is new or changed from the baseline. With the help of CT-guided aspiration for culture analysis, patients can be successfully treated conservatively using antibiotics in cases where neurological signs are absent.