Predicting coverage of transverse subcostal sonography with the use of previous computed tomography before a sonographic liver examination: a prospective study

Impact of ultrasonographic blind spots for early-stage hepatocellular carcinoma during surveillance

Background

Abdominal ultrasonography (US) is the backbone of hepatocellular carcinoma (HCC) surveillance. Although previous studies have evaluated clinical factors related to surveillance failure, none have focused specifically on US blind spots.

Methods

This study included 1,289 patients who underwent 6 months intervals surveillance using US and serum alpha-fetoprotein (AFP) and were eventually diagnosed with single-nodular HCC. Patients were divided into US-detected group (n = 1,062) and US-missed group (HCC detected only by AFP ≥ 20ng/mL; n = 227). Blind spots consisted of four locations: hepatic dome, caudate lobe or around the inferior vena cava, <1 cm beneath the ribs, and the surface of the left lateral segment. Both groups were compared by HCC location, proportional distribution, treatment method, and overall survival.

Results

A higher proportion of HCCs were located within blind spots in the US-missed group than in the US-detected group (64.3% vs. 44.6%, P < 0.001). HCC ≥ 2 cm detected in blind spots was higher than in non-blind areas (60.3% vs. 47.1%, P = 0.001). Blind spot HCCs were more treated with surgery, whereas those located in a non-blind area were more treated with local ablation. Patients with an HCC located within a blind spot in the US-detected group had better overall survival than the same in the US-missed group (P = 0.008).

Conclusions

Using the current surveillance test, blind spots affected the initially detected HCC tumor size, applicability of the treatment modality, and overall survival. Physicians should pay attention to US blind spots when performing US-based HCC surveillance.

Usefulness of Virtual Expiratory CT Images to Compensate for Respiratory Liver Motion in Ultrasound/CT Image Fusion: A Prospective Study in Patients with Focal Hepatic Lesions

Objective

To assess whether virtual expiratory (VE)-computed tomography (CT)/ultrasound (US) fusion imaging is more effective than conventional inspiratory (CI)-CT/US fusion imaging for hepatic interventional procedures.

Materials and Methods

This prospective study was approved by the Institutional Review Board, and informed consent was obtained from each patient. In total, 62 patients with focal hepatic lesions referred for hepatic interventional procedures were enrolled. VE-CT images were generated from CI-CT images to reduce the effects of respiration-induced liver motion. The two types of CT images were fused with real-time US images for each patient. The operators scored the visual similarity with the liver anatomy upon initial image fusion and the summative usability of complete image fusion using the respective five-point scales. The time required for complete image fusion and the number of point locks used were also compared.

Results

In comparison with CI-CT/US fusion imaging, VE-CT/US fusion imaging showed significantly higher visual similarity with the liver anatomy on the initial image fusion (mean score, 3.9 vs. 1.7; p < 0.001) and higher summative usability for complete image fusion (mean score, 4.0 vs. 1.9; p < 0.001). The required time (mean, 11.1 seconds vs. 22.5 seconds; p < 0.001) and the number of point locks (mean, 1.6 vs. 3.0; p < 0.001) needed for complete image fusion using VE-CT/US fusion imaging were significantly lower than those needed for CI-CT/US fusion imaging.

Conclusion

VE-CT/US fusion imaging is more effective than CI-CT/US fusion imaging for hepatic interventional procedures.

Importance of Distending Stomach With Fluid for Ultrasound Detection of Focal Lesion in the Elongated Left Lobe of the Liver

OBJECTIVES

The purpose of this study was to evaluate distending the stomach with water for ultrasound detection of focal lesions in the elongated left lobe of the liver.

METHODS

A total of 13,277 patients undergoing liver ultrasound were evaluated for the presence of an elongated left lobe of the liver and a focal lesion. Patients with an elongated left lobe of the liver had their stomach distended with oral water for further evaluation of a focal lesion. A portion of the patients had computed tomography (CT) examinations, which were compared with the ultrasound studies.

RESULTS

A total of 643 patients were found with elongated left lobe of the liver by ultrasound; of them, 451 underwent CT, 259 out of the 451 patients meeting the inclusion criteria underwent second ultrasound and final analysis, and 16 of these 259 patients had focal lesion in the elongated left lobe of the liver on CT study. The sonographic visualization of the liver and spleen at the same scan view before and after distending the stomach were 7% (7 of 100) and 100% (100 of 100), respectively (P < .001). The sonographic detection of the lesions before and after distending the stomach were zero and 87.5%, respectively (P < .001).

CONCLUSIONS

Distending the stomach with water can greatly increase ultrasound detection of focal lesions in the elongated left lobe of the liver.

Diagnostic criteria for hepatocellular carcinoma ⩽3 cm with hepatocyte-specific contrast-enhanced magnetic resonance imaging

BACKGROUND & AIMS

Current diagnostic imaging criteria for hepatocellular carcinoma (HCC) are dedicated to imaging with nonspecific extracellular contrast agents. This study aimed to evaluate diagnostic criteria for HCC ⩽3 cm on magnetic resonance imaging (MRI) with a hepatocyte-specific contrast agent through an inception cohort study.

METHODS

Of 291 patients with chronic liver disease and new nodules of 1-3 cm in diameter at surveillance ultrasonography, 295 solid nodules (194 HCCs, 98 benign nodules, and three other malignancies) in 198 patients with a confirmed final diagnosis or ⩾24 months follow-up were evaluated on gadoxetic acid-enhanced MRI. Through univariate and multivariate logistic regression analyses, various diagnostic criteria were developed by combining significant MRI findings for diagnosing HCC. The diagnostic performance of each criterion was compared with that of the European Association for the Study of the Liver (EASL) criteria.

RESULTS

Four MRI findings (arterial-phase hyperintensity, transitional-phase hypointensity, hepatobiliary-phase hypointensity, and rim enhancement) were independently significant for diagnosis of HCC ⩽3 cm. For whole nodules, EASL criteria showed the best performance for diagnosing HCC (sensitivity, 83.5%; specificity, 81.2%). For nodules ⩽2 cm in diameter, a new criterion (arterial-phase hyperintensity and hepatobiliary-phase hypointensity) showed a significantly higher sensitivity than that of the EASL criteria (83.0% vs. 74.5%, p=0.008), without a significantly different specificity (76.7% vs. 81.1%, p=0.125).

CONCLUSIONS

EASL criteria exhibit the best diagnostic performance for HCC ⩽3 cm on hepatocyte-specific contrast-enhanced MRI. A newly identified criterion (arterial-phase hyperintensity and hepatobiliary-phase hypointensity) may increase the diagnostic sensitivity of small (⩽2 cm) HCC.