CT and Angiography in Chronic Liver Disease

The cost of screening esophageal varices: traditional endoscopy versus computed tomography

OBJECTIVE

Under current guidelines, patients diagnosed with cirrhosis are to undergo initial and continued screening endoscopy for esophageal varices throughout the course of disease. Recent literature suggests that computed tomography (CT) of the abdomen is adequately sensitive for detecting grade 3 varices, those in need of immediate intervention. This study presents a cost comparison of traditional endoscopy versus CT of the abdomen.

METHODS

Using TreeAge Pro software, a budget impact cost model was created for a hypothetical managed care organization covering 1 million lives over a 10-year period. Incidence figures for cirrhosis and the progression of esophageal varices were applied to the patient population. National Medicare reimbursement costs were used to compare screening with traditional endoscopy versus CT. Costs utilizing screening with combined endoscopy and CT were also examined.

RESULTS

The results of comparing screening paradigms under a budget impact cost model results in an outcome measure termed "per-member, per-month" (PMPM) cost of implementing a new strategy. Computed tomography was the least expensive modality with an average 10-year cost per screened patient of $1097.30 and PMPM of $0.03. Endoscopy was the most expensive modality with an average 10-year cost per screened patient of $1464.89 and PMPM of $0.04.

CONCLUSION

Computed tomography has been shown to be sensitive in detecting esophageal varices and now less costly to implement in screening. The cost of esophageal rupture in endoscopy and the less costly risk of contrast reaction as well as radiation exposure in CT of the abdomen should be considered when developing a screening paradigm.

Detection and grading of esophageal varices on liver CT: comparison of standard and thin-section multiplanar reconstructions in diagnostic accuracy

OBJECTIVE

The objective of our study was to evaluate the performance of liver CT in the diagnosis of esophageal varices in patients with cirrhosis and to determine whether thin-section multiplanar reconstructions (MPRs) improve accuracy.

MATERIALS AND METHODS

We identified 109 patients with cirrhosis who underwent endoscopy within 10 weeks after dual-phase liver MDCT supplemented with thin-section axial and coronal portal venous phase reconstructions. Two blinded radiologists independently evaluated each CT examination for the presence and sizes of varices using standard 5-mm axial versus 1- to 3-mm multiplanar images in separate sessions. Sensitivity, specificity, and predictive value calculations and receiver operating characteristic analysis were performed using endoscopy as the reference standard. Interobserver variability and correlation of CT size to variceal grade were assessed.

RESULTS

Twenty-six cases of high-risk esophageal varices were identified; all except two were detected on CT by one of the readers on standard 5-mm images. For both readers, sensitivity and negative predictive value (NPV) for the discrimination of high-risk varices using a criterion of 2 mm or greater were nearly the same for the standard 5-mm images versus the 1- to 3-mm multiplanar images (sensitivity and NPV: reader 1, 96% and 98% vs 96% and 99%; reader 2, and 89% and 95% vs 89% and 96%, respectively). Standard 5-mm images yielded a lower specificity for high-risk esophageal varices than the thin-section multiplanar images, and this difference was statistically significant for reader 2. Substantial interobserver agreement was noted for both esophageal varices detection and size measurements.

CONCLUSION

Standard liver CT is sensitive for the detection of high-risk varices and deserves further investigation as a potential cost-effective screening tool for the evaluation of patients with cirrhosis. The addition of 1- to 3-mm MPRs may increase specificity for risk stratification based on size measurements.

Detection and grading for esophageal varices in patients with chronic liver damage: comparison of gadolinium-enhanced and unenhanced steady-state coherent MR images

The purpose of this study was to compare observer interpreted steady-state coherent coronal images and gadolinium-enhanced axial images in terms of the detection and grading of esophageal varices. Magnetic resonance imaging (MRI) and gastrointestinal endoscopy were performed within 2 weeks in 90 patients with chronic liver damage, including 55 with untreated esophageal varices, for periodic screening purposes. Two blinded readers retrospectively reviewed T1- and T2-weighted images with gadolinium-enhanced (gadolinium image set) and steady-state coherent (coherent image set) images. Sensitivity for the detection of esophageal varices was higher (P<.001) in the gadolinium image set (76%) than in the coherent image set (35%); on the other hand, specificity was higher (P<.001) in the coherent image set (91%) than in the gadolinium image set (66%). Furthermore, area under the ROC curve was higher for the gadolinium image set (Az=0.823) than the coherent image set (Az=0.761) (P=.48). Moderate and weak positive correlations with endoscopic grades were found for the gadolinium image (r=0.48, P<.01) and coherent image sets (r=0.34, P=.018). The addition of steady-state coherent imaging to the current routine liver imaging protocol did not improve the detection or grading of esophageal varices, whereas gadolinium-enhanced imaging was found to be potentially valuable. Nevertheless, endoscopy was confirmed to be mandatory in patients with esophageal varices suspected by MRI of the liver.

Esophageal varices in cirrhotic patients: evaluation with liver CT

OBJECTIVE

The objective of this study was to evaluate the performance of routine helical liver CT in the detection and grading of esophageal varices in cirrhotic patients.

MATERIALS AND METHODS

A total of 67 consecutive cirrhotic patients who underwent both upper endoscopy and helical liver CT within a 4-week interval were evaluated. The CT protocol included unenhanced, arterial, and portal phases with a collimation of 7-7.5 mm. Two blinded abdominal imagers (6 and 7 years' experience) retrospectively interpreted all CT images to detect the presence of esophageal varices on a 5-point confidence scale and measure the largest varix identified. Receiver operating characteristic (ROC) curve analysis was performed, and the correlation between CT measurements and endoscopic grading, the reference standard, was assessed.

RESULTS

The variceal detection rates for the observers was 92% (11/12) and 92% (11/12) for large (i.e., clinically significant) varices, 53% (16/30) and 60% (18/30) for small varices, and 64% (27/42) and 69% (29/42) for all varices. The area under the ROC curve for the detection of esophageal varices of any size was 0.77 (observer 1) and 0.80 (observer 2). CT variceal grading showed a strong correlation with endoscopic grading for both observers (p < or = 0.001). Using a variceal diameter threshold of 3 mm on CT, sensitivity, specificity, and accuracy for distinguishing large esophageal varices from small or no varices were 92% (11/12), 84% (46/55), and 85% (57/67), respectively, for both observers.

CONCLUSION

Liver CT is useful for the detection and grading of esophageal varices. A diameter of 3 mm may be an appropriate screening threshold for large clinically significant varices.

Esophageal varices: diagnosis with gadolinium-enhanced MR imaging of the liver for patients with chronic liver damage

OBJECTIVE

The purpose of our study was to evaluate the value of gadolinium-enhanced MR imaging of the liver in the detection and grading of esophageal varices in patients with chronic liver damage.

MATERIALS AND METHODS

Three independent off-site radiologists retrospectively reviewed MR images of the liver obtained in 72 patients with chronic liver damage, including 49 patients with untreated esophageal varices. All patients had undergone gastrointestinal endoscopy within 2 weeks of MR imaging. Both MR and endoscopic images were reviewed to determine whether esophageal varices were present and, if so, to determine the grade of the varices. Observer performances were tested with receiver operating characteristic curve analysis using the jackknife dispersion test. Correlations between the grades of the varices determined using MR images and those determined using endoscopic images were tested.

RESULTS

Sensitivity for detection of esophageal varices was significantly (p < 0.01) higher for the combination of unenhanced and gadolinium-enhanced MR images (81%) than for the unenhanced MR images alone (51%). The receiver operating characteristic curve analysis (area under the curve, [A(z)]) showed that performance using the combination of the unenhanced and gadolinium-enhanced MR images (A(z) = 0.641) was superior to that using unenhanced MR images alone (A(z) = 0.586). A statistically significant positive correlation (p < 0.05) was found between the grades determined using MR imaging and the grades determined using endoscopy.

CONCLUSION

Our results suggest the potential value of diagnosing the presence and grade of esophageal varices on MR imaging of the liver for patients with chronic liver damage. Gadolinium-enhanced MR imaging may increase the potential value.

Esophageal and gastric vasculature in children with extrahepatic portal hypertension: evaluation by intravenous CT portography

PURPOSE

To compare the findings related to esophageal/gastric varices and congestive gastropathy on intravenous computed tomography (CT) portography (CTP) and upper gastrointestinal endoscopy (UGIE) in children with extrahepatic portal venous obstruction (EHO) presented with hematemesis.

METHODS/MATERIALS

Fifty pediatric patients (age < 15 years) with EHO (initially diagnosed on abdominal ultrasound) presented with hematemesis and underwent UGIE and intravenous CTP using a helical CT scanner. Axial sections of 2 mm each were obtained with a collimation of 2 mm and a table feed of 3 mm. CTP findings on these axial sections were compared with UGIE (gold standard).

RESULTS

The sensitivity of CTP for detection of esophageal varices, gastric varices, and gastropathy was 32/33 (97%), 38/40 (95%), and 30/32 (93%), respectively. CTP showed false positivity as well, which was 5/17 (29%), 2/10 (20%), and 13/17 (76%) for esophageal varices, gastric varices, and gastropathy, respectively. On follow-up UGIE, the endoscopic features appeared in 14/19 (74%) of false positive patients. Therefore, false positivity for all the parameters on CTP when compared to the initial UGIE represented the changes in vasculature before they were endoscopically manifest.

CONCLUSIONS

CTP was likely to pick up changes in esophageal and gastric vasculature earlier than UGIE in children with EHO presented with hematemesis.