Computed Tomography Perfusion Imaging for the Diagnosis of Hepatic Alveolar Echinococcosis

Multidetector computed tomography assessment of venous invasion in hepatic alveolar echinococcosis

PURPOSE

The objective of this study was to correlate multidetector computed tomography (MDCT) findings in hepatic alveolar echinococcosis (HAE) with intraoperative and postoperative histopathological results to identify reliable MDCT criteria for the diagnosis of HAE venous invasion.

METHODS

A total of 136 HAE patients who underwent CT examination were included in this study. The lesion-vessel contact angle, irregular wall, lumen stenosis and occlusion were evaluated.

RESULTS

A total of 614 veins were estimated. In total, 510 veins were invaded, and 104 veins were not. The invasion rate was 83.06%. In single CT findings, with a cutoff value of > 180° determined by receiver operating characteristic (ROC) curve analysis, the lesion-vessel contact angle performed the best (area under the ROC curve, AUC = 0.907, 95% confidence interval, 95% CI 0.872-0.941, p < 0.001), with a sensitivity, specificity and positive likelihood ratio (PLR) of 84.90%, 88.46%, and 7.35, respectively. Irregular wall and lumen stenosis showed the lowest diagnostic performance. Diagnostic performance was the highest when combining these criteria and signs (AUC = 0.932, 95% CI 0.905-0.960, p < 0.001).

CONCLUSION

The lesion-vessel contact angle > 180° had the best sensitivity and specificity in the diagnosis of HAE venous invasion, and good interobserver agreement had been noted. The diagnostic performance of the lesion-vessel contact angle > 180° had been further improved with the addition of lumen occlusion accompanied by irregular wall or lumen stenosis.

Diagnostic and Management Perspectives in Alveolar Echinococcosis: Review of Literature

Alveolar echinococcosis is a life-threatening zoonotic disease caused by Echinococcus multilocularis. The disease usually primarily involves the liver and shows tumor-like growth. Early diagnosis of alveolar echinococcosis is difficult because the disease is usually asymptomatic in the early stages. Untreated cases are fatal and result in death within 10 years of liver involvement. In the diagnosis of alveolar echinococcosis, the patient's medical history, radiological imaging findings, and serological and histopathological tests are used together. Radiological imaging methods are very important for early diagnosis and differential diagnosis of the disease. In this article, we wanted to review the diagnosis and treatment of alveolar echinococcosis and emphasize the importance of keeping it in mind, especially in cystic lesions of the liver, and the importance of early diagnosis of the disease.

Imaging Aspects of Hepatic Alveolar Echinococcosis: Retrospective Findings of a Surgical Center in Turkey

Radiologists should be aware of the findings of alveolar echinococcosis (AE) due to the diagnostic and management value of imaging. We are attempting to define the most common diagnostic imaging findings of liver AE, along with the prevalence and distribution of those findings. The patients' US, CT, and MRI images were reviewed retrospectively. CT images were acquired with and without the administration of contrast medium. The MRI protocol includes T2-weighted images (WI), diffusion (WI), apparent diffusion coefficient (ADC) maps, and pre- and post-contrast T1WIs. The current study included 61 patients. The mean age of the population was 58.2 ± 9.6 years According to Kratzer's categorization (US), 139 lesions (73.1%) were categorized as hailstorm. According to Graeter's classification (CT), 139 (73.1%) lesions were type 1-diffuse infiltrating. The most frequent types were Kodama type 2 and 3 lesions (MRI) (42.6% and 48.7%, accordingly). P2N0M0 was the most frequent subtype. The current study defines the major, characteristic imaging findings of liver AE using US, CT, and MRI. Since US, CT, and MRI have all been utilized to diagnose AE, we believe that a multi-modality classification system is needed. The study's findings may aid radiologists in accurately and timely diagnosing liver AE.

Extrahepatic alveolar echinococcus on multi-slice computed tomography and magnetic resonance imaging

Alveolar echinococcus (AE) is a severe health problem in endemic areas. In recent years, the incidence of this disease in China has been increasing. The study was designed to illustrate the multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) features of extrahepatic AE. A cohort of 33 patients who suffered from extrahepatic AE was enrolled consecutively from January 2012 to December 2017. The MSCT and MRI features of extrahepatic AE were recorded and analyzed by experienced radiologists. All cases secondary to hepatic AE, except two primary extrahepatic AE, were found in this study. Locations of extrahepatic AE included 19 (57.6%) lung, 10 (30.3%) adrenal gland, 9 (27.3%) brain, 5 (15.2%) peritoneal cavity, 5 (15.2%) spleen, 4 (12.1%) diaphragm, 3 (9.1%) kidney, 3 (9.1%) retroperitoneal, and 2 (6.1%) vertebra; Involvement of 1 (3.0%) heart, 1 (3.0%) mediastinum, 1 (3.0%) muscle, and 1 (3.0%) pancreas was rare. AE of the lung usually appeared as irregular and scattered nodules with small vacuoles or cavities inside and peripheral distribution. Multiple cerebral nodules with calcification and surrounding edema were the most common features seen in brain AE. Adrenal gland AE presented as plaques containing different sizes of hypodense areas and different amounts of calcification. Injection of contrast medium showed no enhancement of lesions except in the brain. MSCT and MRI are reliable imaging methods for the diagnosis of extrahepatic AE. When one AE patient is clinically confirmed, MSCT scan from the chest to the abdomen should be performed to exclude other organs AE.

Simple liver cysts and cystoid lesions in hepatic alveolar echinococcosis: a retrospective cohort study with Hounsfield analysis

BACKGROUND

Alveolar echinococcosis (AE) is a rare zoonosis caused by the larval stage of the tapeworm Echinococcus multilocularis. AE lesions affect the liver in more than 98% of cases. AE lesions have various morphological characteristics that are described in the Echinococcus multilocularis Ulm classification for computed tomography (EMUC-CT). One of these characteristics is a cystoid portion. The aim of the study was to compare the density of simple hepatic cysts with cystoid portions of AE lesions classified on the basis of the EMUC-CT.

RESULTS

Hounsfield Unit (HU) measurements of the cystoid portions of all EMUC-CT type I-IV AE lesions (n = 155) gave a mean of 21.8 ± 17.6, which was significantly different from that of 2.9 ± 4.5 for the simple hepatic cysts (p < 0.0001). The difference between each of the individual AE types and simple hepatic cysts was also significant. In addition, the HU values of the cystoid portions in types I, II and IIIa/b and simple cysts were each significantly different from type IV (p < 0.0001). The HU measurements in type IV presented by far the highest mean.

CONCLUSIONS

The significantly higher density measured in the cystoid portions of hepatic AE lesions offers a good means of differentiation from simple hepatic cysts.

Alveolar Echinococcosis Mimicking a Hepatic Neoplasm with Lymph Node Metastasis: A Case Report

A 37-year-old man had an asymptomatic 17-mm mass in the liver by health check with ultrasonography. Five years later, he was referred to our hospital because the mass was slightly enlarged with a peripancreatic lymph node. We performed endoscopic ultrasonography fine-needle aspiration (EUS-FNA) to evaluate a lymph node, but it showed amorphous eosinophilic material and eosinophilic infiltrate in necrotic tissue of toothpaste-like white specimen. However, we diagnosed as potentially malignant liver mass with lymph node metastasis because of 2-deoxy-2-(fluorine-18) fluorodeoxyglucose uptake. We then performed hepatectomy and enucleation of the pancreas. DNA polymerase chain reaction analysis revealed Echinococcus multilocularis infection. Retrospectively, we could find a part of Echinococcus in the specimens of EUS-FNA.