Venous air embolism in CT coronary angiography.

INTRODUCTION: Venous air embolization (VAE) from IV lines is a risk with IV contrast administration. The incidence of VAE ranges from 7% to 23%. While life-threatening VAE is rare, there is the potential risk of serious cerebrovascular events from paradoxical systemic air embolization (SAE) in patients with congenital intracardiac shunts. CT coronary angiogram (CTCA) hypothetically carries a higher risk of VAE as it requires dual injections as compared to single bolus dose contrast used in CT chest (CTC). The aim of this study was to assess the risk of VAE using CTCA as compared to conventional CTC. The incidence of cardiac shunts and their association with paradoxical SAE were also investigated. METHODS: A retrospective study was conducted at a tertiary hospital. Adult patients undergoing CTCA and CTC over a 6-month period in 2017 were included. Images were reviewed on PACS for the presence of VAE. Electronic medical records were interrogated for evidence of neurological sequelae or requiring neurological imaging (CTB/MRIB) within 1 month of the initial imaging. RESULTS: 508 patients were included, 408 underwent CTCA and 100 underwent CTC. The VAE incidence in CTCA was 24% (94 patients) and 10% in the CTC (10 patients). This was statistically significant. Among the CTCA group, 36% (108 patients) had an intracardiac shunt. No statistically significant difference in VAE incidence was identified in CTCA patients with shunts vs without shunts. There was no incidence of SAE in both groups. CONCLUSION: VAE is more common with CTCA than conventional CTC. There were no cases of paradoxical SAE found.

Is point of care renal function testing reliable screening pre-IV contrast administration?

PURPOSE: Intravenous iodinated contrast is a commonly used diagnostic aid to improve image quality on computed tomography. There exists a small risk of post-contrast acute kidney injury in patients receiving IV contrast. One of the biggest risk factors for developing PC-AKI is the presence of pre-existing renal dysfunction, making it important to measure the renal function prior to contrast administration. Point of care (POC) devices offer a quick estimation of renal function, potentially improving workflows in radiology departments. METHOD: Two POC devices were evaluated, the Nova StatSensor and Abbott iSTAT. Patients undergoing routine radiological investigations had blood collected and analysed by a POC method and the laboratory method (Beckman AU5800). The two values were analysed and compared. Renal function was calculated using eGFR via the CKD-EPI result. eGFR values were stratified as high risk (eGFR < 30), moderate risk (eGFR 30-59) and low risk (eGFR ≥ 60). RESULTS: One hundred eighty-six patients were included in the study. One hundred one patients underwent the Abbott iSTAT analysis, 139 patients underwent Nova StatSensor analysis, and 53 had both. Statistical analysis revealed that the StatSensor R2 value was 0.77, and coefficient variation was 10.65%. iSTAT had a R2 value of 0.83 and coefficient variation of 7.36%. The POC devices did not miss any high-risk patients but underreported eGFR values in certain patients. CONCLUSION: POC devices are moderately accurate at detecting renal impairment in patients undergoing radiological investigations. They seem to be a good screening tool; however, any low eGFR values should be further examined.

The other side tells the story.

We present a patient who presented to the emergency department with a bisphosphonate-induced femoral fracture (BIFF). Clinical presentation, pathogenesis and management of BIFF are discussed. We also highlight the importance of imaging the contralateral femur, as these patients may need prophylactic surgical fixation of the contralateral femur.

Monteggia fracture: an easy fracture to miss.

PURPOSE: To assess the incidence of missed Monteggia fracture by radiologists and bedside clinicians (emergency and orthopaedic doctors) at a tertiary hospital. METHODS: A comprehensive search was conducted on Picture Archiving and Communication System (PACS) and electronic medical records (EMR) between Jan 2010 and April 2019. All consecutive paediatric and adult patients who presented to the emergency department with the diagnosis of Monteggia fracture were included. The patient's emergency presentation medical notes and trauma film reports were compared. Most emergency presentations were discussed with orthopaedics; hence, this was combined as a single group (bedside clinician group). All images were blindly reviewed by a senior consultant radiologist. Results from the radiologist and bedside clinician groups were compared. RESULTS: Fifty-one patients were identified; 4 were excluded as they were not true Monteggia fracture on review. Forty-seven patients were included in the study (age range 3-70 years, mean age 15 years). Thirty-three patients (70%) were correctly diagnosed by both groups. Twelve patients (25.5%) had a missed diagnosis by the radiologist's group. Seven patients (14.9%) were missed by the bedside clinicians. Five patients (10.6%) were missed by both groups with fractures detected on re-presentations. The most commonly missed finding was a radial head dislocation/subluxation, followed by a subtle ulnar fracture (confirmed by periosteal reaction development on subsequent radiographs) and an ulnar plastic deformity. CONCLUSION: The Monteggia fracture is an important diagnosis, but it is not infrequently missed by radiologists and clinicians. Special attention to the radiocapitellar joint alignment and ulnar periosteum, and looking for a subtle ulnar fracture or plastic deformity would ensure correct diagnosis.