Detecting the pulmonary trunk in CT scout views using deep learning

For CT pulmonary angiograms, a scout view obtained in anterior–posterior projection is usually used for planning. For bolus tracking the radiographer manually locates a position in the CT scout view where the pulmonary trunk will be visible in an axial CT pre-scan. We automate the task of localizing the pulmonary trunk in CT scout views by deep learning methods. In 620 eligible CT scout views of 563 patients between March 2003 and February 2020 the region of the pulmonary trunk as well as an optimal slice (“reference standard”) for bolus tracking, in which the pulmonary trunk was clearly visible, was annotated and used to train a U-Net predicting the region of the pulmonary trunk in the CT scout view. The networks’ performance was subsequently evaluated on 239 CT scout views from 213 patients and was compared with the annotations of three radiographers. The network was able to localize the region of the pulmonary trunk with high accuracy, yielding an accuracy of 97.5% of localizing a slice in the region of the pulmonary trunk on the validation cohort. On average, the selected position had a distance of 5.3 mm from the reference standard. Compared to radiographers, using a non-inferiority test (one-sided, paired Wilcoxon rank-sum test) the network performed as well as each radiographer (P < 0.001 in all cases). Automated localization of the region of the pulmonary trunk in CT scout views is possible with high accuracy and is non-inferior to three radiographers.

Measurement of Neck-Shaft Angle Using CT Scout View in Healthy Jordanian Adults - A Reliability and Agreement Study

Aims: To report estimates of the reliability and agreement of a new method for measuring the femoral Neck-shaft angle in the Jordanian population. The neck-shaft angle is an important anatomical indicator in orthopedics of the hip. While there are different approaches to measuring the neck-shaft angle in the literature, there is no agreement on the best technique used for measurement. CT scout view was used in this study to provide a promising alternative. Study Design: Observational reliability and agreement study. Places and Duration of the Study: Department of physiotherapy, school of rehabilitation science, University of Jordan and University of Jordan Hospital between March 2014 and October 2015. Methodology: Two independent raters calculated the neck-shaft angle on each hip of 50 pelvic CT scout images of healthy adults to determine inter-rater reliability. One rater performed the measurement twice to determine the intra-rater reliability. Intra-class correlation coefficients were used to examine relative reliability. The standard error of measurement (SEM) and 95% minimal detectable change (MDC) were calculated to examine absolute reliability. Results: The mean value of all angle measurements was 131.3. Intra-class correlation coefficients were 0.726 and 0.63 for inter and intra-rater measurements respectively. SEM and MDC for inter-rater measurements were 2.69 and 7.46 respectively. For intra-rater measurements, they were 2.84 and 7.86 respectively. Conclusion: The new method proposed in this study for measuring the neck-shaft angle showed good reliability and small measurement error.

CT-guided mapping in the removal of an impalpable, radiopaque foreign body in subcutaneous tissue: a case report

Small fragments sometimes penetrate the soft tissue, and their depth and location can be difficult to determine accurately. This case study describes localisation of a thin, short wire that had penetrated the soft tissue of a 24-year-old man's back, using computed tomography (CT) with a reference grid made with an angiographic catheter. The axial non-contrast-enhanced CT scan with the grid placed over the affected body part surveyed by the CT scout view showed that the foreign body was buried in fascia 7cm from a puncture wound. Surgical removal of the foreign body was then performed without any sequelae. CT with the use of external references that do not cause metal artefacts is a simple and helpful procedure in localising radiopaque foreign bodies.