Improving practice in radiology: a quality-improvement project examining CT colonography patient dose and scanning technique.

AIM: To audit scanning technique and patient doses for computed tomography (CT) colonography (CTC) examinations in a large UK region and to identify opportunities for quality improvement. MATERIALS AND METHODS: Scanning technique and patient dose data were gathered for both contrast-enhanced and unenhanced CTC examinations from 33 imaging protocols across 27 scanners. Measurements of patient weight and effective diameter were also obtained. Imaging protocols were compared to identify technique differences between similar scanners. Scanner average doses were calculated and combined to generate regional diagnostic reference limits (DRLs) for both examinations. RESULTS: The regional DRLs for contrast-enhanced examinations were volume CT dose index (CTDIvol) of 11 and 5 mGy for the two scan phases (contrast-enhanced and either delayed phase or non-contrast enhanced respectively), and dose-length product (DLP) of 740 mGy·cm. For unenhanced examinations, these were 5 mGy and 450 mGy·cm. These are notably lower than the national DRLs of 11 mGy and 950 mGy·cm. Substantial differences in scan technique and doses on similar scanners were identified as areas for quality-improvement action. CONCLUSION: A regional CTC dose audit has demonstrated compliance with national DRLs but marked variation in practice between sites for the dose delivered to patients, notably when scanners of the same type were compared for the same indication. This study demonstrates that the national DRL is too high for current scanner technology and should be revised.

Virtual colonoscopy vs conventional colonoscopy in patients at high risk of colorectal cancer--a prospective trial of 150 patients.

OBJECTIVE: Virtual colonoscopy (VC)/CT colonography has advantages over the well-documented limitations of colonoscopy/barium enema. This prospective blinded investigative comparison trial aimed to evaluate the ability of VC to assess the large bowel, compared to conventional colonoscopy (CC), in patients at high risk of colorectal cancer (CRC). METHOD: We studied 150 patients (73 males, mean age 60.9 years) at high risk of CRC. Following bowel preparation, VC was undertaken using colonic insufflation and 2D-spiral CT acquisition. Two radiologists reported the images and a consensual agreement reached. Direct comparison was made with CC (performed later the same day). Interobserver agreement was calculated using the Kappa method. Postal questionnaires sought patient preference. RESULTS: Virtual colonoscopy visualized the caecum in all cases. Five (3.33%) VCs were classified as inadequate owing to poor distension/faecal residue. CC completion rate was 86%. Ultimately, 44 patients had normal findings, 44 had diverticular disease, 11 had inflammatory bowel disease, 18 had cancers, and 33 patients had 42 polyps. VC identified 19 cancers--a sensitivity and specificity of 100% and 99.2% respectively. For detecting polyps > 10 mm, VC had a sensitivity and specificity (per patient) of 91% and 99.2% respectively. VC identified four polyps proximal to stenosing carcinomas and extracolonic malignancies in nine patients (6%). No procedural complications occurred with either investigation. A Kappa score achieved for interobserver agreement was 0.777. CONCLUSION: Virtual colonoscopy is an effective and safe method for evaluating the bowel and was the investigation of choice amongst patients surveyed. VC provided information additional to CC on both proximal and extracolonic pathology. VC may become the diagnostic procedure of choice for symptomatic patients at high risk of CRC, with CC being reserved for therapeutic intervention, or where a tissue diagnosis is required.

Metastatic adenocarcinoma masquerading as a psoas abscess.

A 71-year-old man presented with signs of a left psoas lesion 4 years after a sigmoid colectomy for adenocarcinoma. Radiological appearances were thought to be typical of an abscess, but an attempted aspiration was unsuccessful. A biopsy was taken and histology showed metastatic adenocarcinoma.

Case report: CT and angiographic appearances of intrasplenic mycotic aneurysm.

A 67-year-old man developed intrasplenic mycotic aneurysms secondary to bacterial endocarditis. The computed tomography (CT) appearances showing enhancing lesions within the spleen are correlated with the angiographic appearances.

Unusual hyperechoic ultrasound appearance of testicular Leydig cell tumour.

Patients with a testicular mass are usually investigated by ultrasound and the ultrasound appearances have been correlated with the histology. The authors describe two patients with Leydig cell tumours. The first had bilateral tumours which although histologically typical of Leydig cell tumours, had differing ultrasound appearances, one with a previously unreported hyperechoic appearance. The second patient had an impalpable tumour with similar ultrasound appearances to those previously described. The paper illustrates the difficulty of giving an accurate diagnosis of solid testicular lesions and also shows that the previously described appearance of Leydig cell tumour is not pathognomonic.

Laparoscopic ultrasound for the detection of hepatic metastases during laparoscopic colorectal cancer surgery.

PURPOSE: The search for liver metastases before surgery forms an accepted part of colorectal cancer surgical practice. Intraoperative ultrasound and manual palpation of liver together form the criterion standard as far as screening for metastases is concerned. However, extracorporeal imaging, such as ultrasound and magnetic resonance imaging, are also widely used. The purpose of this study was to demonstrate the efficacy of laparoscopic ultrasound scan in detection of liver metastases during laparoscopic colorectal cancer surgery by comparison with conventional imaging modalities. METHODS: A prospective, controlled study was undertaken. A total of 76 consecutive patients undergoing laparoscopic colorectal resections for malignancy were recruited. Patients underwent preoperative liver ultrasound scan and intraoperative blinded laparoscopic ultrasound scan examination performed by a single surgeon. Contrast-enhanced magnetic resonance imaging was performed within 30 days of surgery. RESULTS: Conventional ultrasound scan was negative in all cases. Metastases were identified during simple laparoscopic inspection of the liver in one case. Two cases shown by laparoscopic ultrasound scan to have definite metastases were confirmed by magnetic resonance imaging. In seven further instances laparoscopic ultrasound scan identified suspicious liver masses. In three cases these were confirmed to be metastases at magnetic resonance imaging; one was confirmed as a cyst, and the remaining three suspicious lesions were confirmed at serial magnetic resonance imaging scans to be benign and of no significance. CONCLUSION: Laparoscopic ultrasound scan with a flexible-tipped probe permits satisfactory hepatic examination. It is superior to conventional ultrasound scan and seems to be as effective as magnetic resonance imaging, although the latter modality is still required to delineate identified lesions.