Preoperative gastric residual volumes in fasted patients measured by bedside ultrasound: a prospective observational study.

The purpose of this prospective observational study was to measure gastric volumes in fasted patients using bedside gastric ultrasound. Patients presenting for non-emergency surgery underwent a gastric antrum assessment, using the two-diameter and free-trace methods to determine antral cross-sectional area (CSA). Gastric residual volume (GRV) was calculated using a validated formula. Univariate and multivariable analyses were performed to examine any potential relationships between 'at risk' GRVs (>100 ml) and patient factors. Two hundred and twenty-two successful scans were performed; of these 110 patients (49.5%) had an empty stomach, nine patients (4.1%) had a GRV >100 ml, and a further six patients (2.7%) had a GRV >1.5 ml/kg. There was no significant relationship between at risk GRV and obesity, diabetes mellitus, gastro-oesophageal reflux disease or opioid use, although our study had insufficient power to exclude an influence of one or more of these factors. Our results indicate that despite compliance with fasting guidelines, a small percentage of patients still have GRVs that pose a pulmonary aspiration risk. Anaesthetists should consider this background incidence when choosing anaesthesia techniques for their patients. While future observational studies are required to determine the role of preoperative bedside gastric ultrasound, it is possible that this technique may assist anaesthetists in identifying patients with 'at risk' GRVs.

Comparison of the Wells and Revised Geneva Scores for the diagnosis of pulmonary embolism: an Australian experience.

BACKGROUND/AIMS: Clinical prediction rules form an integral component of guidelines on the diagnostic approach to pulmonary embolism (PE). The Wells Score is commonly used but is subjective, while the newer Revised Geneva Score is based entirely on objective variables. The aim of this study was to compare the diagnostic accuracy of the Wells and Revised Geneva Scores for the diagnosis of PE. METHODS: Patients presenting to the emergency department with clinically suspected PE and referred for CT pulmonary angiogram or ventilation/perfusion scintigraphy were evaluated. The Wells and Revised Geneva Scores were calculated on the same cohort of patients and dichotomized into low and intermediate/high probability groups. The sensitivities and specificities were compared using McNemar's test. Overall accuracy was determined using receiver operator characteristic curve analysis. RESULTS: A total of 98 consecutive patients was included. The overall prevalence of PE was 15.3%. The frequency of PE in the low, intermediate and high probability groups was similar for both clinical prediction rules. Compared with the Revised Geneva Score, the Wells Score showed a lower sensitivity with borderline significance (46.7% vs 80.0%, P= 0.06) and a significantly higher specificity (67.5% vs 47.0%, P= 0.002). The overall accuracy of both rules was similar (P= 0.617). CONCLUSION: Using the accepted guidelines in which a high pretest probability leads to further imaging and a low probability leads to a D-dimer blood test, use of the more specific Wells Score could safely reduce the number of unnecessary scans. This would need to be confirmed with larger, prospective trials.

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

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.

Case report: Confined penetration of a duodenal ulcer causing pancreatitis.

Confined penetration of a duodenal ulcer is an unusual cause of pancreatic gas and pancreatitis.

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

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.

Primary gastrointestinal lymphomas: a radiological-pathological review. Part 2: Small intestine.

Primary lymphoma of the small intestine is a heterogeneous group of diseases reflected in its protean imaging features. This review illustrates the widespread appearances seen on imaging methods (primarily CT and barium studies) with pathological correlation.

Primary gastrointestinal lymphomas: a radiological-pathological review. Part 1: Stomach, oesophagus and colon.

Primary gastrointestinal lymphomas are most common in the stomach, followed by small intestine and then colon. The most frequently used pathology classification of lymphomas is the Revised European and American Lymphoma /World Health Organization classification. The correlation of radiological morphology with histology is relatively poor, although characteristic subtypes will be discussed. In the stomach, the majority of primary lymphomas are of B-cell origin of mucosa-associated lymphoid tissue (MALT) type. Low-grade MALT lymphomas are associated with Helicobacter pylori infection and often respond to eradication of this organism. Radiological features include thickened folds, nodularity, depressed lesions, ulcers, prominent areae gastricae. High-grade (large B-cell) tumour patterns include infiltrative, polypoid, nodular, ulcerated or a combination. Endoscopy, endoscopic ultrasound and CT are important in diagnosis and staging, although appearances on barium studies should be recognized. Primary colonic lymphomas are rare. Most are of B-cell origin. Focal and diffuse forms are seen, the former producing polypoid or nodular or cavitating masses and the latter producing ulcerative or nodular (polyposis) patterns on imaging. Even when circumferential, lymphoma rarely causes obstruction. Small bowel lymphomas will be discussed in the forthcoming part 2 of this review.

Virtual colonoscopy: issues in implementation.

The following issues and requirements related to the implementation of a CT colonography (CTC) service are important: (i) policies are needed regarding the indications for CTC. Concomitant with this is the need for education of potential referrers and patients. Expectations of the procedure, particularly by general practitioners, may be unrealistic and indications for referral may otherwise be inappropriate. At present there is not general acceptance of CTC for screening asymptomatic persons; (ii) a flexible approach to CT protocols is useful, dependent on the indication for and clinical context of referral, the age and body habitus of the patient; (iii) attention to the issues related to the special skills required by the reporting radiologist. While there is a temptation to regard CTC interpretation as an extension of skills used in interpreting other cross-sectional images, there is a need to realise that there are skills required specific to CTC and there should be adequate provision for training; (iv) matters related to reporting, such as reporting format, and lesions that will be reported/not reported; and (v) informed consent from the patient. Information should be provided with regard to the limitations of CTC, the implications of a positive finding and radiation dosage.

Randomized single blind trial of two low-volume bowel preparations for screening computed tomographic colonography.

BACKGROUND: Bowel preparation is an important part of computed tomographic colonography (CTC); we evaluated two small-volume preparations for screening CTC with regard to quality of preparation and patient acceptability. METHODS: Asymptomatic subjects at average risk for colorectal cancer from a community-based CTC screening program were randomized to bowel preparation comprising magnesium/bisacodyl/picolax or polyethylene glycol (PEG)/picolax. CTC images were evaluated by a blinded investigator for residual feces and fluid; subjects completed a questionnaire regarding acceptability of the preparation. RESULTS: In 176 subjects randomized to magnesium/bisacodyl/picolax (n = 82) or PEG/picolax (n = 94), the former preparation was discontinued because of syncope or presyncope in four (5%) subjects. Another 137 subjects received PEG/picolax without a significant adverse event. There were no other major differences in acceptability of the preparations as reported by subjects. The quality of bowel preparations for reporting CTC was similar. CONCLUSION: For subjects having screening CTC, both small-volume bowel preparations are generally well tolerated and result in minimal fluid and fecal residue; however, the magnesium/bisacodyl/picolax preparation was accompanied by an unacceptable incidence of syncope and is no longer used by us.

Preoperative assessment of pancreatic malignancy using endoscopic ultrasound.

BACKGROUND: 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.

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 > or = 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.

Pancreatic islet cell tumours presenting as recurrent acute pancreatitis: imaging features in three cases.

We present three cases of recurrent pancreatitis that occurred in patients with small islet cell tumours of the pancreas which were obstructing the main pancreatic duct. This is a very uncommon presentation of pancreatic islet cell tumours. The radiological findings in these cases are shown and the implications for imaging of 'idiopathic' relapsing pancreatitis are discussed.

Computed tomography colonography.

Computed tomography colonography (virtual colonoscopy) is an exciting technique that continues to evolve but promises to be a valuable tool for diagnosis of and screening for colorectal neoplasia.

Virtual colonoscopy compared with conventional colonoscopy: a developing technology.

AIM: To determine the accuracy of computed tomography colography (virtual colonoscopy) in detecting colorectal polyps and colorectal cancer. DESIGN: Blinded comparison of virtual colonoscopy (initially supine-only scans and later supine plus prone scans) with the criterion standard of conventional colonoscopy. SUBJECTS AND SETTING: 100 patients aged 55 years or over referred to a public teaching hospital for colonoscopy, July 1997 to January 2000, because of colonic symptoms or a family history of bowel cancer. MAIN OUTCOME MEASURES: Presence and size of polyps and other lesions; certainty of polyp identification on virtual colonoscopy (on 100-point visual analogue scale); sensitivity and predictive values of virtual colonoscopy. RESULTS: Conventional colonoscopy identifed 121 polyps in 47 patients; 28 of these polyps, in 19 patients, were identified by virtual colonoscopy. Sensitivity of virtual colonoscopy for detecting polyps (using supine plus prone scans) was 73% for polyps with diameter > or = 10 mm (95% CI, 39%-94%) and 19% for smaller polyps (95% CI, 10%-31%) (P < 0.001); corresponding figures for supine-only scans were 57% (95% CI, 18%-90%) and 11% (95% CI, 4%-24%), respectively. Ten polyps identified at virtual colonoscopy were considered false-positive findings (8%). The value of finding a polyp on virtual colonoscopy (with thresholds of 5 mm for diameter and 30 points for certainty score) was assessed as a predictor of finding a polyp (diameter > 5 mm) on conventional colonoscopy. Positive and negative predictive values were 88% and 89%, respectively, for supine plus prone scans. CONCLUSION: Although virtual colonoscopy shows potential as a diagnostic tool for colorectal neoplasia, it is currently not sufficiently sensitive for widespread use.