Optimising image quality in intravenous cerebral cone beam computed tomography.

INTRODUCTION: The efficacy of intravenous cerebral Cone Beam Computed Tomography (IV CBCT) is well established; however, image quality has only ever been authenticated by subjective evaluation. The aim of this study was to quantify the factors pertinent to achieving consistent and optimal image quality when performing IV CBCT. METHODS: Between 1 March 2021 and 30 October 2022, 79 patients received IV CBCT. These candidates were divided into three main acquisition field size categories (22/32, 42 and 48 cm) according to the clinical indication. The images were analysed using both a quantitative assessment and a subjective evaluation. Here, a comparison of Hounsfield units (HUs), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and noise index was conducted for each study and compared relative to the acquisition field size. The subjective analysis was performed in a non-blinded fashion where the diagnostic value (DV) of the exam was determined according to a graded scale. A phantom analysis for each of the acquisition field sizes was conducted and modulation transfer function (MTF) graphed. RESULTS: Significantly higher HU, SNR, CNR and lower noise indices were achieved with the 42-cm protocol than the 22/32 and 48-cm protocols. Here a greater DV was also reported. The MTF demonstrates marginally improved spatial resolution for the 22-cm protocol, but this is near equivocal for the 32-, 42 and 48-cm protocols. CONCLUSION: The use of larger acquisition field sizes provides improved image quality when performing IV CBCT as an alternative to intra-arterial (IA) CBCT.

Comparing the accuracy and complications of peripherally inserted central catheter (PICC) placement using fluoroscopic and the blind pushing technique.

INTRODUCTION: Peripherally inserted central catheters (PICCs) offer a convenient long-term intravenous access option. Different methods exist for insertion including the use of continuous fluoroscopy for guidance, or bedside insertion techniques. The blind pushing technique is a bedside approach which involves advancing a PICC through the access sheath without imaging guidance, before taking a mobile chest radiograph to confirm tip position. Obtaining optimal position is a critical aim of PICC placement as malpositioned lines have been associated with higher complications including death. We aimed to assess the accuracy of PICC placement by comparing the tip position and complications for lines placed under fluoroscopic guidance to those placed without fluoroscopic guidance. METHODS: The Radiology Information System was used to identify 100 continuous PICC insertions in each group (fluoroscopic and blind pushing) between 1 January and 12 May 2019. Patients were excluded if there was a known history of central venous occlusion/stenosis. RESULTS: In the fluoroscopic-guided group, 0% of the lines were malpositioned compared with 60% of the lines placed using the blind pushing technique, P < 0.001. Fluoroscopic-guided PICC insertions were in place for a total of 2446 days and demonstrated 6 complications (2.45 complications per 1000 catheter days). This compared with blind pushing technique PICC insertions which were in place for a total of 1521 days and demonstrated 18 complications (11.83 complications per 1000 catheter days), P = 0.004. CONCLUSION: The use of fluoroscopy for PICC placement leads to significant improvements in tip accuracy than for PICCs placed using the blind pushing technique. While the use of these imaging resources incurs cost and time, these factors should be balanced in order to offer patients the safest and most accurate method of line insertion.

Analysis of time delay between computed tomography and digital subtraction angiography on the technical success of interventional embolisation for treatment of lower gastrointestinal bleeding.

INTRODUCTION: A retrospective study was undertaken to determine a potential relationship, based on the time delay, between a positive lower gastrointestinal bleed demonstrated on computed tomography (CT) and a positive digital subtraction angiographic (DSA) study and the impact on technical success. METHODS: This study investigated the correlation of time delays between imaging modalities and technical success with endovascular embolisation procedures over a 10-year period. RESULTS: A total of 110 patient events were analysed, and it was observed that the greater the time delay between modalities (up to 7 h), the weaker the correlation between a bleed observed on CT and DSA. This was also reflected by the technical success of the embolisation treatment. Patients experienced shorter delays when the event occurred out of normal business hours, however with decreased rates of technical success. CONCLUSIONS: There is a suggestion patients should be escalated to the angiography suite for DSA imaging as soon as possible to maximise the ability to angiographically observe acute bleeding and treat appropriately with interventional embolisation. More research in this area is required to statistically confirm this.

Evaluation of a radiographer-led peripherally inserted central catheter insertion service.

INTRODUCTION: To evaluate a radiographer-led peripherally inserted central catheter (PICC) insertion service within an interventional radiology suite using ultrasound and fluoroscopic guidance. METHODS: Data from 366 consecutive PICC insertions by five trained angiography-specialized radiographers were prospectively collected over a 12-month period. For each PICC insertion, patient demographics, including past medical history of cystic fibrosis (CF), number of punctures, vein used, final tip position, contrast administration and screening time were recorded. Institutional review board approval was obtained. RESULTS: The overall PICC insertion success rate was 100%. Fifty-five (15%) had a known medical history of CF. Three hundred and thirty-one (90%) PICC insertions required a single puncture and 32 (9%) required two punctures. The remaining three insertions required three punctures. The basilic vein was most commonly used (69%) followed by the brachial vein (29%), and the cephalic vein was used only in 2%. Administration of contrast medium was necessary during 27 (7%) PICC insertions. Mean screening time was 10.7 s. CONCLUSION: Our specifically trained, radiographer-led PICC insertion service proved to be successful. Both straightforward and complex insertions, for example in CF patients could be adequately and efficiently performed.

Local diagnostic reference levels for angiographic and fluoroscopic procedures: Australian practice.

Although diagnostic and interventional fluoroscopic procedures are amongst the highest dose examinations performed in radiology, these procedures currently lack established national diagnostic reference levels (DRLs) in Australia. In this absence, local diagnostic reference levels (LDRLs) are proposed for a wide range of diagnostic and interventional angiographic and fluoroscopic procedures based upon data collected from 11,000 examinations, performed over a 2.5 year period at a major Australian public, teaching hospital. Each procedure type assessed included a minimum of 50 cases. LDRLs were defined for each procedure in terms of the 75th percentile of the dose area product and median fluoroscopic times have also been provided. The detailed categories of procedures used in this study may inform the Australian Radiation Protection and Nuclear Safety Agency when establishing national DRLs for angiographic and fluoroscopic procedures. Until national DRLs for these complex procedures are available, these LDRLs may provide guidance to other institutions on achievable dose levels.