Audit of ultrasonography findings in cases of abnormal MRCP

An audit to compare the findings on ultrasound performed prior to abnormal MRCP examinations.

Abdominal ultrasound is usually the first-line imaging investigation in evaluating the  biliary tree, but is highly dependent on both operator and patient factors

Extrahepatic biliary dilatation is the most sensitive and quantifiable method on ultrasound for indicating a biliary obstruction, but ultrasound has a relatively low sensitivity (25-60%) for the visualisation of causes of biliary duct dilatation (e.g intraductal calculi).

MRCP has a very high sensitivity and specificity for determining causes of biliary obstruction and is routinely used as a safe non-invasive second-line imaging investigation in patients with a dilated extrahaptic bilary duct on ultrasound.

The standard: 

Where MRCP demonstrates common bile duct dilatation, ultrasonography performed prior to the MRCP should identify a dilated extrahepatic biliary tree in 90% of cases.

Target: 

1. 90% accurate identification of MRCP detected biliary dilatation on preceding ultrasound

2. The ultrasound should contain a specific comment referring to either the presence or absence of extrahepatic biliary dilatation - 100%

3. If the cause of biliary dilatation is not shown on ultrasound, appropriate recommendation for further imaging (MRCP or CT) or referral included in the report– 100%

Indicators: 

- The description of a dilated common bile duct in the ultrasound report

- A clear recommendation for further imaging if no cause of biliary dilatation seen on ultrasound

Data items to be collected: 

- 100 consecutive abnormal MRCP reports then identify how many had preceding ultrasound within a reasonable time frame (eg 4 weeks) 

- Review reports of abdominal ultrasounds performed within theagreed timeframe prior to abnormal MRCP and document findings on ultrasound

Suggested number: 

100

• Present the findings to the local ultrasound user groups

• Emphasise the importance of mentioning the presence and cause of a dilated biliary tree on the report

• Emphasise especially the importance of stating appropriate recommendations for further imaging or referral if the cause of biliary dilatation is unclear on ultrasound

• Circulate results to individual users

• With PACS collection of reports and review of images is greatly facilitated

• 5-10 hours to review reports and images if required

1. Shanmugam et al. Is magnetic resonance cholangiopancreatography the new gold standard in biliary imaging? British Journal of Radiology Vol 78, 888-893 2005 http://bjr.birjournals.org/content/78/934/888.full 

2. Attasaranya S. et al. Choledocholithiasis, Ascending Cholangitis, and Gallstone Pancreatitis. Med Clin N Am 92 (2008) 925–960 http://xa.yimg.com/kq/groups/23984489/2116843903/name/colangite.pdf

3. Bluth E. et al. Ultrasound: a practical approach to clinical problems. Ch.2 2nd Revised edition edition. 2008 Thieme

4. Yusuf T and Bhutani M. Endoscopic Ultrasonography and Bile Duct Stones. J Gastroenterol Hepatol 19(3):243-250,2004.

5. Kaltenthaler E et al. A systematic review and economic evaluation of magnetic resonance cholangiopancreatography compared with diagnostic endoscopic retrograde cholangiopancreatography. Health Technology Assessment 2004;Vol.8: No.10.

6. Clinical Audit in Radiology 100+ Recipes. Dr. S.Jones. Ultrasound scanning in obstructive jaundice. Recipe 108: 217-218.

Samuel Stafrace, Janabel Galea. Updated by D Howlett, and J Parikh