Assessment of abdominal sonography in the diagnosis of tumors of the gastroduodenal tract

Basic practices for gastrointestinal ultrasound

The standard diagnostic modalities for gastrointestinal (GI) diseases have long been endoscopy and barium enema. Recently, trans-sectional imaging modalities, such as computed tomography and magnetic resonance imaging, have become increasingly utilized in daily practice. In transabdominal ultrasonography (US), the bowel sometimes interferes with the observation of abdominal organs. Additionally, the thin intestinal walls and internal gas can make structures difficult to identify. However, under optimal US equipment settings, with identification of the sonoanatomy and knowledge of the US findings of GI diseases, US can be used effectively to diagnose GI disorders. Thus, the efficacy of GIUS has been gradually recognized, and GIUS guidelines have been published by the World Federation for Ultrasound in Medicine and Biology and the European Federation of Societies for Ultrasound in Medicine and Biology. Following a systematic scanning method according to the sonoanatomy and precisely estimating the layered wall structures by employing color Doppler make diagnosing disease and evaluating the degree of inflammation possible. This review describes current GIUS practices from an equipment perspective, a procedure for systematic scanning, typical findings of the normal GI tract, and 10 diagnostic items in an attempt to help medical practitioners effectively perform GIUS and promote the use of GIUS globally.

Comparison of contrast media for visualization of the colon of healthy dogs during computed tomography and ultrasonography

OBJECTIVE To evaluate contrast agents for their ability to improve visualization of the colon wall and lumen during CT and ultrasonography. ANIMALS 10 healthy adult Beagles. PROCEDURES Food was withheld from dogs for 36 hours, after which dogs consumed 250 mL of polyethylene glycol solution. Dogs were then anesthetized, a contrast agent (tap water, diluted barium, or air; order randomly assigned) was administered rectally, iodine contrast medium (880 mg of I/kg) was administered IV, and CT and ultrasonography of the colon were performed. After a 1-week washout period, this process was repeated with a different contrast agent until all agents had been evaluated. Two investigators reviewed the CT and ultrasonographic images for colon wall thickness, conspicuity, artifacts, wall layering, and degree of lumen dilation at 4 sites. RESULTS Thickness of the colon wall was greatest in CT and ultrasonographic images with water used as contrast agent, followed by barium and then air. The CT images obtained after water administration had a smooth appearance that outlined the colonic mucosa and had the highest score of the 3 contrast agents for wall conspicuity. Although no substantial artifacts related to any of the contrast agents were identified on CT images, barium- and gas-induced shadowing and reverberation artifacts hindered wall evaluation during ultrasonography. For ultrasonography, the degree of conspicuity was highest with barium in the near-field wall and with water in the far-field wall. In contrast to CT, ultrasonography could be used to distinguish wall layering, and the mucosal and muscular layers were distinct with all contrast agents. CONCLUSIONS AND CLINICAL RELEVANCE Use of water as a contrast agent for both CT and ultrasonography of the colon in dogs compensated for each imaging modality's disadvantages and could be beneficial in the diagnosis of colon disease.

Sensitivity of ultrasonography for gastric cancer diagnosis in symptomatic patients

Endoscopy with biopsy sampling is the gold standard used in gastric cancer diagnosis. However, the positive predictive value of signs and symptoms for the diagnosis of carcinomas is quite limited, and, therefore, many patients are subjected to non-diagnostic endoscopies, especially when symptoms are not so specific. This study shows that ultrasonography is sensitive enough for the diagnosis of gastric cancer, and, therefore, use of this technique would further ensure a better selection of patients for endoscopy. The study included 143 patients (86 men and 57 women, with an average age of 68.6 years) who were suspected of having gastric cancer. The diagnostic accuracy of ultrasonography was evaluated in a blind study. The conventional technique was used in all cases. Demographic parameters and a series of other clinical-analytical variables were studied to look for possible gastric cancer predictive factors, which when present would make ultrasonographic results irrelevant. Statistical analysis was done using SPSS 12.0, wherein a value of P < 0.05 was considered to be statistically significant. Of the 143 patients studied, 40 were diagnosed to have gastric cancer. Sonography was able to diagnose 37 cases correctly, while there were three false negative findings and eight false positive findings. This results in 92.5% sensitivity, 92.2% specificity, 82.2% positive predictive value, 96.9% negative predictive value, and a global accuracy of 92.3%. Univariate analysis showed that persistent vomiting (P = 0.021), hemoglobin level of less than 8 g/dl (P = 0.045) and a positive ultrasonography result (P < 0.0001) were associated with a higher frequency of gastric cancer. Multivariate analysis showed that persistent vomiting, with an odds ratio for gastric cancer of 3.68 (95% confidence interval 1.15-11.79; P = 0.039), and a positive ultrasonography result, with an odds ratio for gastric cancer of 117.78 (95% confidence interval 32.45-427.49; P < 0.0001), could be considered as independent predictive factors for gastric cancer. It was concluded that ultrasonography is a very sensitive and specific technique for diagnosing gastric cancer. Gastric cancer was found to be present in just 28% of the patients studied, and their condition was suspect because of the clinical manifestations. Only vomiting and a positive ultrasonography result can be considered as independent predictive factors of gastric cancer.

Thickening of the gastric wall on transabdominal sonography: a sign of gastric cancer

PURPOSE

To determine the value of a thickened gastric wall detected during transabdominal sonography (TAS) in the diagnosis of gastric cancer.

METHOD

This prospective study comprised 312 patients who underwent both TAS and endoscopy. Transverse TAS scanning was performed using a 3.5-MHz curved transducer to measure gastric wall thickness in the antrum and body of the stomach. Based on endoscopic and histologic findings, we classified the patients into 3 groups: normal or benign disease (BD), early gastric cancer (EGC), and advanced gastric cancer (AGC). TAS findings were then compared.

RESULTS

The thickness of the gastric wall was 4.9 +/- 1.6 mm in 262 patients with BD, 5.6 +/- 2.4 mm in 21patients with EGC, and 10.3 +/- 4.7 mm in 29 patients with AGC (p < 0.01). A gastric wall thickness of greater than 7 mm had a 75.0% sensitivity, 92.6% specificity, 50.0% positive predictive value, and 97.4% negative predictive value in the diagnosis of AGC.

CONCLUSION

Although not suitable as a screening method for gastric cancer, a thickening of the gastric wall of >7 mm may be a marker for AGC.

Extraluminal gastrointestinal stromal tumour in the second portion of the duodenum

The preoperative diagnosis of extraluminal gastrointestinal stromal tumours in the duodenum is difficult to establish due to their rare occurrence and the lack of pathognomonic signs. This report describes the case of a 61-year-old woman who suffered from an immunohistologically confirmed gastrointestinal stromal tumour in the second portion of the duodenum. Preoperative, abdominal, multislice computed tomography showed an extraluminal but intramural tumour located between the head of the pancreas and the duodenum. Rapid postprocessing analysis by three-dimensional, volume-rendered images revealed a strong arterial blood supply and an early draining vessel into the superior mesenteric vein during the portal-venous phase. The combination of endoscopic ultrasonography and non-invasive multislice computed tomography provided an early suggestion of gastrointestinal stromal tumour.