Richard M Mendelson

Extracolonic findings at virtual colonoscopy: implications for screening programs.

OBJECTIVE:Virtual colonoscopy (VC) is an evolving technology proposed as a possible screening tool for colorectal cancer. In contrast to conventional colonoscopy, VC may detect extracolonic abdominal pathology. This may lead to unnecessary investigation of benign lesions, or may benefit the patient by identifying serious pathology at an early stage. The aim of this study was to assess the prevalence and characteristics of extracolonic pathology found in patients undergoing VC.METHODS:A total of 100 patients aged ≥55 yr, referred for colonoscopy for bowel symptoms or family history of bowel cancer, underwent VC. Axial views of the abdomen were reviewed prospectively by a single radiologist for extracolonic pathology. Patients with extracolonic abnormalities were referred to their local doctor or to a specialist clinic when appropriate. Case records were reviewed and treating doctors contacted to document subsequent investigations and procedures generated.RESULTS:Fifteen patients (15%) had extracolonic abnormalities detected. In four patients, the pathology had been diagnosed previously (umbilical hernia, gallbladder and renal calculi, 3.5-cm aortic aneurysm, ovarian cyst). Eleven patients had new abnormalities detected: ovarian cysts (three), liver cysts (two), uterine fibroids (two), gallstones (one), splenic calcifications (one), aortic aneurysm (one), and renal tumor (one). Two patients with ovarian cysts underwent surgery, and histology showed benign cysts.CONCLUSIONS:Extracolonic abnormalities are common at VC. Most are benign, but may lead to investigative and procedural costs. These data should be carefully evaluated in feasibility and cost-effectiveness studies on colorectal cancer screening using VC.

Community-Based Screening by Colonoscopy or Computed Tomographic Colonography in Asymptomatic Average-Risk Subjects

OBJECTIVES:Visualizing the entire colorectum in screening is an advantage of colonoscopy, and also computed tomographic (CT) colonography, another potentially suitable screening test. Our objective was to compare screening CT colonography and colonoscopy in an asymptomatic average-risk population, and to determine whether providing a choice of tests increased participation.METHODS:One thousand and four hundred subjects from the general community, randomly selected from the parliamentary electoral roll, were allocated one of three screening groups: colonoscopy, CT colonography, or a choice of these tests, and were sent an institutional letter of invitation. Those with symptoms, colorectal cancer in first-degree relatives, or colonoscopy within 5 yr were ineligible. Outcome measures were participation, acceptability of screening, and yield for advanced colorectal neoplasia in participants.RESULTS:Of the subjects, 24.9% were ineligible; the overall participation rate was 18.2% (184/1,009). Participation in each screening group was not different. Both tests were accompanied by the same high levels of acceptability; most participants found colonoscopy (87%) and CT colonography (67%, p < 0.001) less unpleasant than expected. About 29% (26/89) CT colonography subjects had a positive screening test. The yield of advanced colorectal neoplasia was 8.7% (95% CI 5–14%), with no difference in yield between tests.CONCLUSION:Colorectal neoplasia screening by colonoscopy or CT colonography was associated with modest participation, high levels of acceptability, and similar yield for advanced colorectal neoplasia. Providing a choice of test did not increase participation.

Computed Tomographic Colonography: Prevalence, Nature, and Clinical Significance of Extracolonic Findings in a Community Screening Program

OBJECTIVE:Colorectal neoplasia screening by computed tomographic colonography (CTC) may lead to the detection of incidental extracolonic findings. We report the prevalence and clinical significance of extracolonic pathology found within a community-based CTC screening program and the cost of clinical follow-up and further investigation of these findings.METHODS:A total of 432 asymptomatic subjects at an average risk of colorectal neoplasia, aged 50–69, had screening by CTC using a low radiation dose protocol. Axial images were prospectively examined for extracolonic lesions and those considered clinically relevant were followed up. All clinic visits and further investigations were tallied to calculate the incremental cost to the screening CTC.RESULTS:A total of 146 extracolonic lesions were detected in 118 (27.3%) subjects. Thirty-two (7.4%) subjects had clinically relevant extracolonic abnormalities and nine (2.1%) subjects may derive a clinical benefit from the detection of these lesions. A single CTC costed

Vascular complications of pancreatitis.

171.12, and following up extracolonic findings resulted in an additional

Student and intern awareness of ionising radiation exposure from common diagnostic imaging procedures.

24.37 (14.2%) per CTC. Limiting reporting to the aorta and kidneys would have reduced the number of subjects requiring follow-up to 14 (3.2%), and decreased the cost increment to 4.7% without detriment to clinical outcome.CONCLUSIONS:Extracolonic findings of screening CTC are common, but infrequent of clinical importance. The additional burden of following up these findings was modest and could have been further reduced if clear clinical and radiological criteria and pathways for their further investigation were defined.

COMPUTED TOMOGRAPHY IN THE ASSESSMENT OF SUSPECTED LARGE BOWEL OBSTRUCTION

Vascular complications of pancreatitis are a major cause of morbidity and mortality. Arterial complications include haemorrhage from direct arterial erosion or pseudoaneurysm formation, and visceral ischaemia. Venous complications predominantly are related to splanchnic vein thrombosis. This review, with illustrative cases, describes the main manifestations of these complications and emphasizes the importance of early radiological diagnosis and intervention.

Non-invasive prediction of the degree of liver fibrosis in patients with hepatitis C using an ultrasound contrast agent. A pilot study.

This study aims to evaluate medical student and intern awareness of ionising radiation exposure from common diagnostic imaging procedures and to suggest how education could be improved. Fourth to sixth year medical students enrolled at a Western Australian university and interns from three teaching hospitals in Perth were recruited. Participants were asked to complete a questionnaire consisting of 26 questions on their background, knowledge of ionising radiation doses and learning preferences for future teaching on this subject. A total of 331 completed questionnaires were received (95.9%). Of the 17 questions assessing knowledge of ionising radiation, a mean score of 6.0 was obtained by respondents (95% CI 5.8–6.2). Up to 54.8% of respondents underestimated the radiation dose from commonly requested radiological procedures. Respondents (11.3 and 25.5%) incorrectly believed that ultrasound and MRI emit ionising radiation, respectively. Of the four subgroups of respondents, the intern doctor subgroup performed significantly better (mean score 6.9, P < 0.0001, 95% CI 6.5–7.3) than each of the three medical student subgroups. When asked for the preferred method of teaching for future radiation awareness, a combination of lectures, tutorials and workshops was preferred. This study has clearly shown that awareness of ionising radiation from diagnostic imaging is lacking among senior medical students and interns. The results highlight the need for improved education to minimise unnecessary exposure of patients and the community to radiation. Further studies are required to determine the most effective form of education.

Preoperative assessment of pancreatic malignancy using endoscopic ultrasound

Background:  The aim of this study was to assess the efficacy of computed tomography (CT) scanning in the diagnosis of acute large bowel obstruction.

Pre-operative staging of gastro-oesophageal junction carcinoma: comparison of endoscopic ultrasound and computed tomography.

It has been shown that the severity of hepatic fibrosis in patients with hepatitis C can be predicted non‐invasively by measuring intrahepatic circulatory time (IHCT) using a microbubble agent with spectral Doppler analysis. The aim of this study was to assess whether this technique is reproducible using a third‐generation microbubble agent and contrast harmonic imaging, which are becoming the standard ultrasound techniques in all radiology departments. Twenty‐three untreated patients with hepatitis C, who had undergone a recent liver biopsy, were studied prospectively. Based on their histological fibrosis score, patients were divided into four groups (fibrosis levels 1–4). Contrast harmonic imaging was carried out after an intravenous bolus of a microbubble agent (Optison; Amersham Health, Milwaukee, WI, USA). IHCT was calculated by measuring the difference between the hepatic vein and hepatic artery microbubble arrival times. The IHCT was compared with the degree of fibrosis. Significant differences were shown between the groups for IHCT. There were significant differences between fibrosis levels 1 and 3 and between fibrosis levels 1 and 4. This study has shown that calculation of IHCT using a third‐generation microbubble agent and contrast harmonic imaging can differentiate mild fibrosis from more severe degrees of fibrosis in patients with hepatitis C.

Inappropriate imaging: why it matters, why it happens, what can be done.

AbstractBackground: Endoscopic ultrasound (EUS) has been regarded as the most accurate modality for locoregional staging of pancreatic malignancy. However, several recent studies have questioned this. The current study assessed the accuracy of EUS in determining preoperative resectability of pancreatic neoplasia. Methods: A retrospective review was performed of patients with pancreatic malignancy who had preoperative EUS and underwent surgery. EUS-predicted resectability was compared with surgical resectability. Where available, accuracies of vascular and nodal staging were also assessed. Results: Forty-five patients were identified (mean age = 60 years, age range = 36–79 years). All patients underwent surgical exploration; vascular staging was available in 32 cases and 17 cases underwent surgical resection. The sensitivity, specificity, and accuracy of EUS in determining unresectability were 66%, 100%, and 78% respectively. Overall EUS stage concurred with surgical stage in 56%, greater than surgical stage in 4%, and less than surgical stage in 40%. Vascular staging on EUS had a sensitivity of 69% and a specificity of 100%. Accuracy of nodal staging was 71%. Conclusion: EUS had a high specificity for assessing unresectable pancreatic malignancy. This technique should be used to avoid unnecessary surgical exploration of incurable lesions. However, EUS had only a moderate sensitivity, and a proportion of patients staged preoperatively as having resectable disease will not be surgically resectable.