Introducing a cardiac CT service - ensuring appropriate referrals and overcoming teething problems

Abstract

s / Clinical Radiology 67 (2012) S11–S20 S18 Transjugular liver biopsy safety and diagnostic yield Authors: Amit Patel, Aman Khan, Pete Thurley, Dominic Clarke, Rajeev Singh Background to the audit: Previous studies have demonstrated transjugular liver biopsy (TJLB) to be an effective procedure in patients not suitable for percutaneous biopsy with high diagnostic yield and low complication rate. Standard, indicator and target: To compare our centres complication rates and outcomes with previously published national studies. Technical success rates previously quoted range from 85 to 91%. Complication rates range from 1.3 to 13%. Methodology: Retrospective review of all TJLB's performed at Royal Derby Hospital between 2009 to 2012. Data gathered from case-note review, CRIS and Isoft medical database. Results of 1st audit round: Number of cases 1⁄4 47. Common indications included alcoholic liver diseasewith ascites/coagulopathy or suspected HCC. Mean age 1⁄4 55 years (range 22-82 years). Mean PT 18, INR 1.6, PLT 177. Large majority required pre-procedural blood products. Technical success rate 1⁄4 45/47 (96%). Mean number of passes 1⁄4 2.4. Mean combined core length 1⁄4 22 mm (range 4-45). Histological diagnostic yield 1⁄4 41/45 (91%). In 4 patients, samples were haemorrhagic precluding definitive histological assessment. Early complication rate 1⁄4 1/47 (2%). One patient developed small subcapsular extravasation identified during procedure and settled spontaneously. Late complication rate 1⁄4 Nil. 1st Action Plan: To disseminate results across department and related clinical specialties. Standardisation of number of cores required for histological diagnosis and continuation of audit cycle. Are CT KUBS being performed with as low a radiation dose as possible? Authors: Adrian A. Pollentine, David Wilson, Alexis Corrigan, Mark Hawkins Background to the audit: We aim to audit whether CTKUB examinations are complying to the principle of keeping radiation exposure ALARP & whether changes to protocol and technique recommended after first round of audit have been effectively implemented. Standard, indicator and target: All CTKUBs performed on the correct CTKUB protocol Cranial extent of the scan should be at the top of the kidneys Meagher T, Sukumar VP, Collingwood J, et al. Low dose computed tomography in suspected acute renal colic. Clin Radiol. 2001 Nov;56(11):873-6 Methodology: All CTKUBs over 3 month periods July-Sept 2010 & AprilJune 2011 were analysed. Age, gender, DLP, kV, scanner used, AP diameter of patient at renal pelvis, distance scanned above kidney w 120kV on CT2 and 100kV on CT1 12% of scans on incorrect protocol Mean examination dose 1⁄4 4.5mSv Mean scan distance above kidney 1⁄4 62mm. 1st action plan: All scans to be performed on correct protocol Top of scan to be top of kidneys – not for repeat if tip of kidney missed 100 kV across both scanners Resultsof 2nd round: Statistically significant reduction inbothdose from4.5 to3.5mSvanddegreeof overestimationof cranial limit of scanfieldby20mm No repeat if top of kidney excluded initially – Compliant All scans performed on correct protocol – Non-compliant but improvement made 6% vs 12% 2nd action plan: Re-audit after introduction of iterative reconstruction software. Introducing a cardiac CT service ensuring appropriate referrals and overcoming teething problems Authors: Adrian A. Pollentine, Anthony Edey, Ladli Chandratreya Background to the audit:We aim to audit appropriateness of referrals for cardiac CT as well as factors contributing towards optimal image production and highlight tips to overcoming initial problems and providing a top notch service. Standard, indicator and target: Cardiac CT referral should adhere to appropriateness criteria published 2010 by the American College of Cardiologists 90% All patients should have on table GTN (unless C/I) 100% Heart rate should be 1000CTPAs annually. It is important to minimise the effective dose of this frequently performed study whilst maintaining diagnostic quality in accordance with IR(ME)R 2000. Standard, indicator and target: Standard 1: All CTPAs should be diagnostic (mean PA HU >200) Standard 2: Dose should be as low as reasonably practicable (mean DLP Methodology: 50 CTPAs performed at 120kVp on 128-slice CT scanner were reviewed. Mean HU in main pulmonary artery (MPA) was measured. Proportion of non-diagnostic CTPAs determined. Effective dose calculated from DLP, using conversion factors. Results of 1st audit round: At 120kVp: Standard 1: 98% CTPAs were diagnostic. Mean attenuation in MPA1⁄4355HU Standard 2: 100% compliance. Mean DLP1⁄4287mGy.cm, Effective dose1⁄44.9mSv 1st action plan: CT tube output is a to kVp squared. Lowering kVp can reduce dose and increase attenuation as more photons approximate to the k-edge of iodine and undergo photoelectric absorption. Perform CTPA at 100kVp rather than 120kVp to lower effective dose without compromising diagnostic quality. Re-audit 50 CTPAs. Results of 2nd round: At 100kVp: Standard 1: 96% CTPAswere diagnostic. Mean attenuation inMPA1⁄4 419HU* Standard 2: 100% compliance. Mean DLP 1⁄4124mGy.cm, Effective dose 1⁄42.0mSv* (*2nd Vs 1st round, P<0.05) 2nd action plan: Perform CTPA at 100kVp as Departmental standard.