Assessment of tumor vascularization with functional computed tomography perfusion imaging in patients with cirrhotic liver disease

BACKGROUND:Hepatocellular carcinoma(HCC)is a common malignant tumor in China,and early diagnosis is critical for patient outcome.In patients with HCC,it is mostly based on liver cirrhosis,developing from benign regenerative nodules and dysplastic nodules to HCC lesions,and a better understanding of its vascular supply and the hemodynamic changes may lead to early tumor detection.Angiogenesis is essential for the growth of primary and metastatic tumors due to changes in vascular perfusion,blood volume and permeability.These hemodynamic and physiological properties can be measured serially using functional computed tomography perfusion(CTP)imaging and can be used to assess the growth of HCC.This study aimed to clarify the physiological characteristics of tumor angiogenesis in cirrhotic liver disease by this fast imaging method. METHODS:CTP was performed in 30 volunteers without liver disease(control subjects)and 49 patients with liver disease (experimental subjects:27 with HCC and 22 with cirrhosis). All subjects were also evaluated by physical examination, laboratory screening and Doppler ultrasonography of the liver. The diagnosis of HCC was made according to the EASL criteria. All patients underwent contrast-enhanced ultrasonography, pre-and post-contrast triple-phase CT and CTP study.A mathematical deconvolution model was applied to provide hepatic blood flow(HBF),hepatic blood volume(HBV), mean transit time(MTT),permeability of capillary vessel surface(PS),hepatic arterial index(HAI),hepatic arterial perfusion(HAP)and hepatic portal perfusion(HPP)data. The Mann-Whitney U test was used to determine differences in perfusion parameters between the background cirrhotic liver parenchyma and HCC and between the cirrhotic liver parenchyma with HCC and that without HCC.RESULTS:In normal liver,the HAP/HVP ratio was about 1/4. HCC had significantly higher HAP and HAI and lower HPP than background liver parenchyma adjacent to the HCC.The value of HBF at the tumor rim was significantly higher than that in the controls.HBF,HBV,HAI,HAP and HPP,but not MTT and PS,were significantly higher in the cirrhotic liver parenchyma involved with HCC than those of the controls. Perfusion parameters were not significantly different between the controls and the cirrhotic liver parenchyma not involved with HCC. CONCLUSIONS:CTP can clearly distinguish tumor from cirrhotic liver parenchyma and controls and can provide quantitative information about tumor-related angiogenesis, which can be used to assess tumor vascularization in cirrhotic liver disease.

Computed tomography perfusion study of hemodynamic changes and portal hyperperfusion in a rabbit model of small-for-size liver

BACKGROUND:Portal hyperperfusion in the small-for-size (SFS) liver can threaten survival of rabbits.Therefore,it is important to understand the hemodynamic changes in the SFS liver.METHODS:Twenty rabbits were divided into two groups:a control group and a modulation group.The control group underwent an extended hepatectomy.The modulation group underwent the same procedure plus splenectomy to reduce portal blood flow.CT perfusion examinations were performed on all rabbits before and after operation.Perfusion parameter values,especially portal vein perfusion (PVP),were analyzed.RESULTS:PVP in the modulation group was lower than in the control group after operation (P=0.002).In the control group,postoperative PVP increased by 193.7±55.1% compared with preoperative PVP.A weak correlation was found between the increased percentage of PVP and resected liver-to-body weight ratio (RLBWR) (r=0.465,P=0.033).In the modulation group,postoperative PVP increased by 101.4±32.5%.No correlation was found between the increased percentage of PVP and RLBWR (r=0.167,P=0.644).Correlations were found between PVP and serum alanine aminotransferase,aspartate aminotransferase,and total bilirubin after surgery (P<0.05).CONCLUSION:We successfully evaluated the characteristics of hemodynamic changes as well as the effects of splenectomy in the SFS liver in rabbits by the CT technique.

Detection and differentiation of early hepatocellular carcinoma from cirrhosis using CT perfusion in a rat liver model

BACKGROUND： Functional imaging such as CT perfusion can detect morphological and hemodynamic changes in he- patocellular carcinoma （HCC）. Pre-carcinoma and early HCC nodules are difficult to differentiate by observing only their hemodynamics changes. The present study aimed to investi- gate hemodynamic parameters and evaluate their differential diagnostic cut-off between pre-carcinoma and early HCC nodules using CT perfusion and receiver operating characteristic （ROC） curves. METHODS： Male Wistar rats were randomly divided into control （n=20） and experimental （n=70） groups. Diethylnitrosamine （DEN） was used to induce pre-carcinoma and early HCC nodules in the experimental group. Perfusion scanning was carried out on all survival rats discontinuously from 8 to 16 weeks. Hepatic portal perfusion （HPP）, hepatic arterial fraction （HAF）, hepatic arterial perfusion （HAP）, hepatic blood volume （HBV）, hepatic blood flow （HBF）, mean transit time （MTT） and permeability of capillary vessel surface （PS） data were provided by mathematical deconvolution model. The perfusion parameters were compared among the three groups of rats （control, pre-carcinoma and early HCC groups） using the Kruskal-Wallis test and analyzed with ROC curves. Histological examination of the liver tissues with hematoxylin and eosin staining was performed after CT scan.RESULTS： For HPP, HAF, HBV, HBF and MTT, there were significant differences among the three groups （P〈0.05）. HAF had the highest areas under the ROC curves： 0.80 （control vs pre-carcinoma groups） and 0.95 （control vs early HCC groups） with corresponding optimal cut-offs of 0.37 and 0.42, respectively. The areas under the ROC curves for HPP was 0.79 （control vs pre-carcinoma groups） and 0.92 （control vs early HCC groups） with corresponding optimal cut-offs of 136.60 mL/min/100 mg and 108.47 mL/min/100 mg, respectively. CONCLUSIONS： CT perfusion combined with ROC curve analysis is a new diagnosis model for distinguishing between pre-carcinoma and early HCC nodules. HAF and HPP are the ideal reference indices.

Application of CT Perfusion Imaging Technology in the Diagnosis of Hepatitis and Liver Cirrhosis

Images obtained via computer tomography perfusion(CTP) technology, a non-invasive functional imaging method, can reflect the hemodynamic status and function of the liver. Images obtained via CTP imaging technology can be quantitatively analyzed. The fundamentals, examination, and analysis of CTP images are reviewed in this paper. In addition, this paper provides a review of normal liver CTP imaging, CTP research status, and future developments in the CTP imaging of hepatitis and liver cirrhosis.

Computed tomography vs liver stiffness measurement and magnetic resonance imaging in evaluating esophageal varices in cirrhotic patients:A systematic review and meta-analysis

BACKGROUND Computed tomography(CT),liver stiffness measurement(LSM),and magnetic resonance imaging(MRI)are non-invasive diagnostic methods for esophageal varices(EV)and for the prediction of high-bleeding-risk EV(HREV)in cirrhotic patients.However,the clinical use of these methods is controversial.AIM To evaluate the accuracy of LSM,CT,and MRI in diagnosing EV and predicting HREV in cirrhotic patients.METHODS We performed literature searches in multiple databases,including Pub Med,Embase,Cochrane,CNKI,and Wanfang databases,for articles that evaluated the accuracy of LSM,CT,and MRI as candidates for the diagnosis of EV and prediction of HREV in cirrhotic patients.Summary sensitivity and specificity,positive likelihood ratio and negative likelihood ratio,diagnostic odds ratio,and the areas under the summary receiver operating characteristic curves were analyzed.The quality of the articles was assessed using the quality assessment of diagnostic accuracy studies-2 tool.Heterogeneity was examined by Q-statistic test and I2 index,and sources of heterogeneity were explored using metaregression and subgroup analysis.Publication bias was evaluated using Deek’s funnel plot.All statistical analyses were conducted using Stata12.0,Meta Disc1.4,and Rev Man5.3.RESULTS Overall,18,17,and 7 relevant articles on the accuracy of LSM,CT,and MRI in evaluating EV and HREV were retrieved.A significant heterogeneity was observed in all analyses(P<0.05).The areas under the summary receiver operating characteristic curves of LSM,CT,and MRI in diagnosing EV and predicting HREV were 0.86(95%confidence interval[CI]:0.83-0.89),0.91(95%CI:0.88-0.93),and 0.86(95%CI:0.83-0.89),and 0.85(95%CI:0.81-0.88),0.94(95%CI:0.91-0.96),and 0.83(95%CI:0.79-0.86),respectively,with sensitivities of 0.84(95%CI:0.78-0.89),0.91(95%CI:0.87-0.94),and 0.81(95%CI:0.76-0.86),and 0.81(95%CI:0.75-0.86),0.88(95%CI:0.82-0.92),and 0.80(95%CI:0.72-0.86),and specificities of 0.71(95%CI:0.60-0.80),0.75(95%CI:0.68-0.82),and 0.82(95%CI:0.70-0.89),and 0.73(95%CI:0.66-0.80),0.87(95%CI:0.81-0.92),and 0.72(95%CI:0.62-0.80),respectively.The corresponding positive likelihood ratios were 2.91,3.67,and 4.44,and 3.04,6.90,and2.83;the negative likelihood ratios were 0.22,0.12,and 0.23,and 0.26,0.14,and 0.28;the diagnostic odds ratios were 13.01,30.98,and 19.58,and 11.93,49.99,and 10.00.CT scanner is the source of heterogeneity.There was no significant difference in diagnostic threshold effects(P>0.05)or publication bias(P>0.05).CONCLUSION Based on the meta-analysis of observational studies,it is suggested that CT imaging,a non-invasive diagnostic method,is the best choice for the diagnosis of EV and prediction of HREV in cirrhotic patients compared with LSM and MRI.

Low contrast medium and radiation dose for hepatic computed tomography perfusion of rabbit VX2 tumor

AIM:To evaluate the feasibility of low contrast medium and radiation dose for hepatic computed tomography(CT) perfusion of rabbit VX2 tumor.METHODS:Eleven rabbits with hepatic VX2 tumor underwent perfusion CT scanning with a 24-h interval between a conventional tube potential(120 k Vp) protocol with 350 mg I/m L contrast medium and filtered back projection,and a low tube potential(80 k Vp) protocol with 270 mg I/m L contrast medium with iterative reconstruction.Correlation and agreement among perfusion parameters acquired by the conventional and low dose protocols were assessed for the viable tumor component as well as whole tumor.Image noise and tumor-to-liver contrast to noise ratio during arterial and portal venous phases were evaluated.RESULTS:A 38% reduction in contrast medium dose(360.1 ± 13.3 mg I/kg vs 583.5 ± 21.5 mg I/kg,P < 0.001) and a 73% decrease in radiation dose(1898.5 m Gy·cm vs 6951.8 m Gy·cm) were observed.Interestingly,there was a strong positive correlation in hepatic arterial perfusion(r = 0.907,P < 0.001;r = 0.879,P < 0.001),hepatic portal perfusion(r = 0.819,P = 0.002;r = 0.831,P = 0.002),and hepatic blood flow(r = 0.945,P < 0.001;r = 0.930,P < 0.001) as well as a moderate correlation in hepatic perfusion index(r = 0.736,P = 0.01;r = 0.636,P = 0.035) between the low dose protocol with iterative reconstruction and the conventional protocol for the viable tumor component and the whole tumor.These two imaging protocols provided a moderate but acceptable agreement for perfusion parameters and similar tumorto-liver CNR during arterial and portal venous phases(5.63 ± 2.38 vs 6.16 ± 2.60,P = 0.814;4.60 ± 1.27 vs 5.11 ± 1.74,P = 0.587).CONCLUSION:Compared with the conventional protocol,low contrast medium and radiation dose with iterative reconstruction has no significant influence on hepatic perfusion parameters for rabbits VX2 tumor.

Computed tomography perfusion in liver and spleen for hepatitis B virus-related portal hypertension:A correlation study with hepatic venous pressure gradient

BACKGROUND Hepatic venous pressure gradient(HVPG)is the gold standard for diagnosis of portal hypertension(PH).However,its use can be limited because it is an invasive procedure.Therefore,it is necessary to explore a non-invasive method to assess PH.AIM To investigate the correlation of computed tomography(CT)perfusion of the liver with HVPG and Child-Pugh score in hepatitis B virus(HBV)-related PH.METHODS Twenty-eight patients(4 female,24 male)with gastroesophageal variceal bleeding induced by HBV-related PH were recruited in our study.All patients received CT perfusion of the liver before transjugular intrahepatic portosystemic stent-shunt(TIPS)therapy.Quantitative parameters of CT perfusion of the liver,including liver blood flow(LBF),liver blood volume(LBV),hepatic artery fraction,splenic blood flow and splenic blood volume were measured.HVPG was recorded during TIPS therapy.Correlation of liver perfusion with Child-Pugh score and HVPG were analyzed,and the receiver operating characteristic curve was analyzed.Based on HVPG(>12 mmHg vs≤12 mmHg),patients were divided into moderate and severe groups,and all parameters were compared.RESULTS Based on HVPG,18 patients were classified into the moderate group and 10 patients were classified into the severe group.The Child-Pugh score,HVPG,LBF and LBV were significantly higher in the moderate group compared to the severe group(all P<0.05).LBF and LBV were negatively associated with HVPG(r=-0.473,P<0.05 and r=-0.503,P<0.01,respectively),whereas splenic blood flow was positively associated with hepatic artery fraction(r=0.434,P<0.05).LBV was negatively correlated with Child-Pugh score.Child-Pugh score was not related to HVPG.Using a cutoff value of 17.85 mL/min/100 g for LBV,the sensitivity and specificity of HVPG≥12 mmHg for diagnosis were 80%and 89%,respectively.CONCLUSION LBV and LBF were negatively correlated with HVPG and Child-Pugh scores.CT perfusion imaging is a potential non-invasive quantitative predictor for PH in HBV-related liver cirrhosis.

Assessment of hepatic functional reserve by cirrhosis grading and liver volume measurement using CT

AIM： To explore a method for quantitative assessment of hepatic functional reserve by combining computed tomography （CT） volumetry with CT grading of liver cirrhosis before liver resection in patients with hepatocellular carcinoma. METHODS： CT images of 55 patients undergoing liver resection were studied prospectively. The degree of liver cirrhosis was referred as ＂CT grade＂ and the percentage of remnant liver volume （PRLV） [PRLV = predicted RLV/predicted total liver volume （PTLV） × 100%; PTLV （mL） = 121.75 ＋ 16.49 × body mass （kg）] were calculated by adding slice by slice of CT liver images. The postoperative RLV, pathologic stages of liver fibrosis in non-tumor area and survival time in these cases were analyzed. RESULTS： There was a significant difference in survival time between the group with PRLV ≤ 50% and the group with PRLV 〉 50% （X^2= 4.988, P = 0.026）, and between the group with CT grade 0/1 and the group with CT grade 2/3 （X^2= 5.429, P = 0.026）. With combination of the both parameters, an oblique line was identified according to the distribution of 32 survivors versus 23 deceased subjects. The mortality rate above the line was 7.1% （1/14）, and that below the line was 53.7% （22/41）, indicating a significant difference between the two rates （X^2 = 9.281, P = 0.002, P 〈 0.05）. CONCLUSION： PRLV and CT grades are significantly correlated with hepatic functional reserve. The predicted line using these two parameters is useful in candidates undergoing liver resection for judging hepatic functional reserve.

Correlation between hepatic blood flow and liver function in alcoholic liver cirrhosis

AIM: To elucidate the correlation between hepatic blood flow and liver function in alcoholic liver cirrhosis (AL-LC).

Early changes of hepatic hemodynamics measured by functional CT perfusion in a rabbit model of liver tumor

BACKGROUND:Early detection and treatment of hepatocellular carcinoma is crucial to improving the patients’ survival.The hemodynamic changes caused by tumors can be serially measured using CT perfusion.In this study,we used a CT perfusion technique to demonstrate the changes of hepatic hemodynamics in early tumor growth,as a proof-of-concept study for human early hepatocellular carcinoma.METHODS:VX2 tumors were implanted in the liver of ten New Zealand rabbits.CT perfusion scans were made 1 week(early) and 2 weeks(late) after tumor implantation.Ten normal rabbits served as controls.CT perfusion parameters were obtained at the tumor rim,normal tissue surrounding the tumor,and control liver;the parameters were hepatic blood flow,hepatic blood volume,mean transit time,permeability of capillary vessel surface,hepatic arterial index,hepatic arterial perfusion and hepatic portal perfusion.Microvessel density and vascular endothelial growth factor were correlated.RESULTS:At the tumor rim,compared to the controls,hepatic blood flow,hepatic blood volume,permeability of capillary vessel surface,hepatic arterial index,and hepatic arterial perfusion increased,while mean transit time and hepatic portal perfusion decreased on both early and late scans(P<0.05).Hepatic arterial index increased(135%,P<0.05),combined with a sharp increase in hepatic arterial perfusion(182%,P<0.05) and a marked decrease in hepatic portal perfusion(-76%,P<0.05) at 2 weeks rather than at 1 week(P<0.05).Microvessel density and vascular endothelial growth factor showed significant linear correlations with hepatic blood flow,permeability of capillary vessel surface and hepatic arterial index,but not with hepatic blood volume or mean transit time.CONCLUSION:The CT perfusion technique demonstrated early changes of hepatic hemodynamics in this tumor model as proof-of-concept for early hepatocellular carcinoma detection in humans.

Perfusion CT findings in liver of patients with tumor during chemotherapy

AIM: To investigate the microcirculation changes in liver of patients with tumor during chemotherapy by perfusion computed tomography (CT). METHODS: Sixty patients with tumor and 20 controls were enrolled in this study. Perfusion CT parameters of patients and controls were compared, including hepatic perfusion index (HPI), mean transit time (MTT), and permeability-surface area product (PS). Correlation between perfusion CT parameters, treatment cycle and alanine aminotransferase (ALT) level was studied. RESULTS: No difference was found in HPI (25.68% ± 7.38% vs 26.82% ± 5.13%), MTT (19.67 ± 5.68 s vs21.70 ± 5.43 s) and PS (17.00 ± 4.56 mL/100 mL per min vs 19.92 ± 6.35 mL/100 mL per min) between pa- tients and controls. The HPI and MTT were significantly higher in patients undergoing 2 cycles of chemotherapy than in controls and those undergoing 1 cycle of che- motherapy (29.76% ± 5.87% vs 25.68% ± 7.38% and 25.35% ± 4.05%, and 25.61 ± 5.01 s vs 19.67 ± 5.68 s and 19.74 ± 4.54 s, respectively, P < 0.05). The HPI was higher in patients with hepatic steatosis than in controls and those without hepatic steatosis (30.85% ± 6.17% vs 25.68% ± 7.38% and 25.70% ± 4.24%, P < 0.05). Treatment cycle was well correlated with HPI and MTT (r = 0.40, r = 0.50, P < 0.01). ALT level was not correlated with perfusion CT parameters. CONCLUSION: HPI and MTT are significantly increased in patients with tumor during chemotherapy and well correlated with treatment cycle. Chemotherapy affects hepatic microcirculation in patients with tumor. Changes in hepatic microcirculation can be quantitatively assessed by perfusion CT.

Detection of liver micrometastases from colorectal origin by perfusion CT in a rat model

BACKGROUND: Some patients with colorectal carcinoma have liver metastases(LMs) which cannot be detected by conventional imaging. This study aimed to assess whether hepatic perfusion changes induced by micrometastases can be detected by perfusion computed tomography(CT).METHODS: LMs were produced in rats by injecting carcinoma cells into the portal vein. Perfusion CT was performed at microscopic(day 10), interval(day 17), and macroscopic stage(day 34). Perfusion parameters were computed using a dualinput one-compartmental model.RESULTS: Micro and macro LMs presented a mean diameter of 0.5 and 2.6 mm, respectively. Compared to controls, LMs at interval(1.1 mm) and macroscopic stage induced significant perfusion changes: a decrease of 42%(P=0.004) and 41%(P=0.029) in hepatic transit time and an increase of 292%(P=0.073) and 240%(P=0.001) in portal delay, respectively.CONCLUSIONS: LMs with a mean diameter between 1.1 and2.6 mm induced significant hepatic perfusion changes, detected by CT. Such detection may help to select patients and propose chemotherapy at the time of primary tumor resection.

Hepatic focal nodular hyperplasia in children:Imaging features on multi-slice computed tomography

AIM:To retrospectively analyze the imaging features of hepatic focal nodular hyperplasia(FNH) in children on dynamic contrast-enhanced multi-slice computed tomography(MSCT) and computed tomography angiography(CTA) images.METHODS:From September 1999 to April 2012,a total of 218 cases of hepatic FNH were confirmed by either surgical resection or biopsy in the Sun Yat-sen Memorial Hospital of Sun Yat-sen University and the Cancer center of Sun Yat-sen University,including 12 cases(5.5%) of FNH in children(age ≤ 18 years old).All the 12 pediatric patients underwent MSCT.We retrospectively analyzed the imaging features of FNH lesions,including the number,location,size,margin,density of FNH demonstrated on pre-contrast and contrastenhanced computed tomography(CT) scanning,central scar,fibrous septa,pseudocapsule,the morphology of the feeding arteries and the presence of draining vessels(portal vein or hepatic vein).RESULTS:All the 12 pediatric cases of FNH had solitary lesion.The maximum diameter of the lesions was 4.0-12.9 cm,with an average diameter of 5.5 ± 2.5 cm.The majority of the FNH lesions(10/12,83.3%) had well-defined margins.Central scar(10/12,83.3%) and fibrous septa(11/12,91.7%) were commonly found in children with FNH.Central scar was either isodense(n = 7) or hypodense(n = 3) on pre-contrast CT images and showed progressive enhancement in 8 cases in the equilibrium phase.Fibrous septa were linear hypodense areas in the arterial phase and isodense in the portal and equilibrium phases.Pseudocapsule was very rare(1/12,8.3%) in pediatric FNH.With the exception of central scars and fibrous septa within the lesions,all 12 cases of pediatric FNH were homogenously enhanced on the contrast-enhanced CT images,significantly hyperdense in the arterial phase(12/12,100.0%),and isodense in the portal venous phase(7/12,58.3%) and equilibrium phase(11/12,91.7%).Central feeding arteries inside the tumors were observed on CTA images for all 12 cases of FNH,whereas no neovascularization of malignant tumors was noted.In 9 cases(75.0%),there was a spoke-wheel shaped centrifugal blood supply inside the tumors.The draining hepatic vein was detected in 8 cases of pediatric FNH.However,the draining vessels in the other 4 cases could not be detected.No associated hepatic adenoma or hemangioma was observed in the livers of the 12 pediatric cases.CONCLUSION:The characteristic imaging appearances of MSCT and CTA may reflect the pathological and hemodynamic features of pediatric FNH.Dynamic multi-phase MSCT and CTA imaging is an effective method for diagnosing FNH in children.

Clinical application of hepatic CT perfusion

Complicated changes occur in hemodynamics of hepatic artery and vein, and portal vein under various kinds of pathologic status hepatic blood supply. This because of distinct double article reviews the clinical application of hepatic computed tomography perfusion in some liver diseases.

Epithelioid angiomyolipoma of the liver:Cross-sectional imaging findings of 10 immunohistochemically-verified cases

AIM： To retrospectively evaluate the computed tomography （CT）/magnetic resonance imaging （MRI） imaging features of epithelioid angiomyolipoma of the liver （Epi-HAML）, with pathology as a reference. METHODS： The CT/MRI findings （number, diameter, lobar location, and appearance of lesions） in a series of 10 patients with 12 pathologically proven epithelioid angiomyolipomas of the liver were retrospectively analyzed. The imaging features, including attenuation/ signal intensity characteristics, presence of fat, hypervascular, outer rim, and vessels within lesion, were evaluated and compared with that of non-Epi- HAML in 11 patients （13 lesions）. The Fisher exact test was used to compare difference in probability of imaging features between the two types. RESULTS： For 21 patients, CT images of 15 patients and MR images of six patients were available. No patient underwent two examinations. For the 15 patients with a CT scan, all HAML lesions in the two groups （10 Epi-HAML and seven non-Epi-HAML） manifested as hypoattenuation. For the six patients with MRI, all lesions （two Epi-HAML and six non-Epi- HAML） were hypointense on TlWI （fat suppression） and hyperintense on T2WI. There were 10 non-Epi-HAML, but only two Epi-HAML lesions showed the presence of fat, which significantly different between the two types （P = 0.005）. On the dynamic contrast enhancement （DCE） imaging, eight Epi-HAML, and 13 non-Epi lesions manifested as hypervascular. Punctate or curved vessels were displayed in 10 Epi-HAML as well as in nine non- Epi lesions and outer rim enhancement could be found with eight Epi-HAML as well as six non-Epi lesions. CONCLUSION： Little or no presence of adipose tissue was found to be an imaging feature of Epi- HAML, compared with the non-Epi type. In addition, hypervascularity with opacification of central punctiform or filiform vessels on DCE would be a characteristic enhancement pattern for Epi-HAML.

Perivascular epithelioid cell tumor of the liver:A report of two cases and review of the literature

Perivascular epithelioid cell tumor (PEComa) is a rare tumor which arises from mesenchymal tissues. It is predominant in the uterus,but very rare in the liver. To the best of our knowledge,less than 5 cases of PEComa of the liver have been reported. Herein we present two pathologically proven cases of PEComa of the liver,retrospectively analyze their clinical and imaging features,and review the literature.

Characteristics of common solid liver lesions and recommendations for diagnostic workup

Due to the widespread clinical use of imaging modalities such as ultrasonography,computed tomography and magnetic resonance imaging (MRI),previously unsuspected liver masses are increasingly being found in asymptomatic patients.This review discusses the various characteristics of the most common solid liver lesions and recommends a practical approach for diagnostic workup.Likely diagnoses include hepatocellular carcinoma (the most likely;a solid liver lesion in a cirrhotic liver) and hemangioma (generally presenting as a mass in a non-cirrhotic liver).Focal nodular hyperplasia and hepatic adenoma should be ruled out in young women.In 70% of cases,MRI with gadolinium differentiates between these lesions.Fine needle core biopsy or aspiration,or both,might be required in doubtful cases.If uncertainty persists as to the nature of the lesion,surgical resection is recommended.If the patient is known to have a primary malignancy and the lesion was found at tumor staging or follow up,histology is required only when the nature of the liver lesion is doubtful.

CT assessment of liver hemodynamics in patients with hepatocellular carcinoma after argon-helium cryoablation

BACKGROUND:Assessment of tumor response after argonhelium cryoablation is critical in guiding future therapy for unresectable hepatocellular carcinoma.This study aimed to evaluate liver hemodynamics in hepatocellular carcinoma after argon-helium cryoablation with computed tomography perfusion.METHODS:The control group comprised 40 volunteers without liver disease.The experimental group was composed of 15 patients with hepatocellular carcinoma treated with argon-helium cryoablation.Computed tomography perfusion parameters were measured:hepatic blood flow,hepatic blood volume,mean transit time,permeability of capillary vessel surface,hepatic arterial fraction,hepatic arterial perfusion,and hepatic portal perfusion.RESULTS:After treatment,in the tumor foci,permeability of capillary vessel surface was higher,and hepatic blood flow,hepatic blood volume,hepatic arterial fraction,and hepatic arterial perfusion values were lower(P【0.05).In the liver parenchyma surrounding the tumor,hepatic arterial perfusion was significantly lower(P【0.05);however,there was no significant difference in hepatic blood flow,hepatic blood volume,mean transit time,permeability of capillary vessel surface,hepatic arterial fraction,or hepatic portal perfusion(P】0.05).CONCLUSION:Computed tomography perfusion can evaluate tumor response after argon-helium cryoablation.

Correlation between Calcified Liver Metastases and Histopathology of Primary Colorectal Carcinoma in Chinese

The study examined the association between calcified liver metastases and the histopathology of the primary colorectal carcinoma in Chinese.The clinical,pathological and CT data were retrospectively analyzed in 210 patients (mean age:54.2 years) with liver metastases from colorectal carcinoma.Plain CT scanning and contrast-enhanced scanning were performed in all the patients.For the contrast-enhanced examination,iohexol was injected by using a high pressure syringe at a flow rate of 2.5-3.0 mL/s.The arterial phase lasted approximately 25 s and the portal venous phase about 60 s.All patients had no history of chronic liver diseases and had never received interventional treatments.χ 2-test was used to analyze the rate of calcification in the liver metastasis from colorectal cancer of different differentiation degrees.Among the 210 cases of liver metastases,22 patients (10.5%) were found to have calcified liver metastases on CT scan.Two patients with calcified liver metastasis received lumpectomy and developed calcification in recurrent tumors.Another two patients had calcification in newly developed tumor masses.And the calcification in the newly developed masses was similar to that of their primary counterparts in terms of morphology and distribution.On the enhanced CT scan,the tumors exhibited no enhancement during hepatic arterial phase and showed slight rim enhancement during portal venous scan in the 22 cases.The calcification became obscure on contrast-enhanced scans.Histopathologically,the primary tumors were well-differentiated adenocarcinoma in 6 cases,moderately-differentiated adenocarcinoma in 10,poorly-differentiated adenocarcinoma in 4 and mucinous adenocarcinoma in 2 among the 22 cases.No statistical correlation was noted between the incidence of calcified liver metastasis and the pathological subtypes and differentiation degrees of the primary colorectal carcinoma.It was concluded that calcified liver metastases may result from colorectal adenocarcinomata of different differentiation degrees or mucinous adenocarcinomata in Chinese population.There is no correlation between calcification of liver metastases and the pathological subtype of the primary colorectal carcinoma in Chinese,which is different from the findings that calcified metastases were associated with colorectal mucinous adenocarcinoma in other ethnic groups.

Liver involvement in patients with COVID-19 infection:A comprehensive overview of diagnostic imaging features

During the first wave of the pandemic,coronavirus disease 2019(COVID-19)infection has been considered mainly as a pulmonary infection.However,different clinical and radiological manifestations were observed over time,including involvement of abdominal organs.Nowadays,the liver is considered one of the main affected abdominal organs.Hepatic involvement may be caused by either a direct damage by the virus or an indirect damage related to COVID-19 induced thrombosis or to the use of different drugs.After clinical assessment,radiology plays a key role in the evaluation of liver involvement.Ultrasonography(US),computed tomography(CT)and magnetic resonance imaging(MRI)may be used to evaluate liver involvement.US is widely available and it is considered the first-line technique to assess liver involvement in COVID-19 infection,in particular liver steatosis and portal-vein thrombosis.CT and MRI are used as second-and third-line techniques,respectively,considering their higher sensitivity and specificity compared to US for assessment of both parenchyma and vascularization.This review aims to the spectrum of COVID-19 liver involvement and the most common imaging features of COVID-19 liver damage.