Optimising central venous catheter placement by comparing cavoatrial junction position to chest X-ray landmarks: A cross-sectional study using CT chest reconstruction.

INTRODUCTION: Central venous catheter (CVC) tip placement guided by chest X-ray (CXR) landmarks is currently prone to inconsistency and malpositioning. This study aims to better define the relationship between the cavoatrial junction (CAJ) and selected X-ray landmarks. METHODS: Chest CTs of 100 patients were retrospectively assessed. CT images were converted to a 'virtual CXR' using a digital workstation, enabling simultaneous localisation of the CAJ and evaluation of CXR landmarks. Vertical distances between the CAJ and selected landmarks were measured for each patient. Measurements were assessed for correlation with age and compared between age groups and sexes. RESULTS: The mean vertical distance of the following landmarks above the CAJ was found: the carina (46.2 mm), the intersection of the bronchus intermedius and the right heart border (7.6 mm) and the superior inflection of the right heart border (Sup-RHB) (13.0 mm). The maximum lateral bulge of the right heart border (Lat-RHB) was 18.4 mm below the CAJ. A new landmark: the mid-superior right heart border, defined as the mid-point between the Sup-RHB and Lat-RHB, was the closest to the CAJ, lying 2.6 mm below the CAJ. CONCLUSION: We propose that the CVC tip can be placed at the mid-superior right heart border landmark.

Comparison of diagnostic accuracy of ultra low-dose computed tomography and X-ray of the kidneys, ureters and bladder for urolithiasis in the follow-up setting.

INTRODUCTION: Urolithiasis is frequently followed up with a low-dose computed tomography of the kidneys ureters and bladder (LD-CTKUB) with doses typically less than 3 millisieverts. Although X-ray is a lower dose (0.5-1.1 mSv) alternative for follow up, it has lower diagnostic accuracy and is limited to radiopaque calculi. This study aims to compare the diagnostic accuracy of sub-millisievert ultra-low dose CT (ULD-CTKUB) against X-ray KUB for the follow up of urolithiasis when both are compared against the standard of care of a low-dose CT KUB (LD-CTKUB). METHODS: This prospective study included patients with a known diagnosis of urolithiasis on prior CTKUB presenting for follow up. Each patient underwent a repeat reference LD-CTKUB, ULD-CTKUB and X-ray KUB. All imaging studies were interpreted by three readers. The radiation dose and quantitative noise was calculated for each CT. Both CT and X-ray were assessed for the presence, number and size of all calculi ≥2 mm. RESULTS: A total of 58 patients were included in this study. LD-CTKUB identified 197 calculi. ULD-CTKUB in our study had a mean effective dose of 0.5 mSv compared to X-ray KUB where doses range in the literature from 0.5 to 1.1 mSv. Per-patient pooled analysis for intrarenal calculi when comparing ULD-CTKUB versus X-ray KUB against a reference LD-CTKUB found a sensitivity of 90% versus 67% (P < 0.01) and specificity of 93% versus 98% (P = 0.18) respectively. For ureteric calculi, the sensitivity was 67% versus 33% (P < 0.01) and specificity 94% versus 94% (P = 1.00) respectively. Per-stone pooled analysis detection rate was 79% for ULD-CTKUB versus 48% for X-ray (P < 0.01) when each was compared to the reference LD-CTKUB. Interobserver agreement was high for intrarenal calculi and moderate for ureteric calculi. CONCLUSION: Sub-millisievert ULD-CTKUB had lower doses and higher sensitivity than X-ray in patients requiring follow up of known urolithiasis.

Stewart-Bluefarb syndrome following traumatic arteriovenous malformation.

Stewart-Bluefarb syndrome is a rare angioproliferative disorder that presents as violet plaques on the extremities, due to an underlying arteriovenous malformation (AVM). We report the case of a 12-year-old boy who developed a traumatic AVM in a bicycle accident and presented seven years later with exophytic, violet plaques. This is the first instance of a traumatic AVM preceding Stewart-Bluefarb syndrome in a pediatric patient in the literature. Given the typically long period required to establish this diagnosis, it is crucial for clinicians to actively interrogate a history of preceding trauma in patients presenting with acroangiodermatitis.