Influence of liver cirrhosis on pseudolesions in liver at CT during arterial portography

Gallbladder fossa nodularity in the liver typically observed in patients with alcoholic liver disease; comparison with chronic hepatitis C patients

BACKGROUND AND PURPOSE

Gallbladder fossa nodularity (GBFN) is often observed in patients with alcoholic liver disease (ALD), and we hypothesized this may be due to the cholecystic venous drainage (CVD), sparing this area from portal perfusion containing alcohol absorbed in the alimentary tract, and also escaping from alcohol-induced fibrotic and atrophic change of the liver parenchyma. The purpose of this study is to verify our hypothesis, using chronic hepatitis C (CHC) patients as a control.

MATERIALS AND METHODS

Between 2013 and 2017, consecutive 45 ALD and 46 CHC patients who had contrast-enhanced CT were retrospectively recruited. Those who had interventions or disease involvement around gallbladder fossa were excluded. All CT images, and angiography-assisted CT(ang-CT) images , when available, were reviewed. GBFN was subjectively classified into grades 0-3, depending upon the conspicuity of nodularity, which was compared between the groups, and was also correlated to various clinicoradiological factors, including the alcohol consumption grades (ACG).

RESULTS

GBFN was more frequently observed in ALD than in CHC patients, and higher grade GBFN was associated with ALD rather than CHC (all p < 0.05). Multivariable analysis revealed independently significant factors related to GBFN grades were ACG and albumin-bilirubin grades. Ang-CT images were available in 11 patients, all of whom exhibited portal perfusion diminishment and faint arterial enhancement, suggesting CVD, at the region of GBFN. When GBFN grade 3 was considered to discriminate ALD from CHC, the value of sensitivity/specificity/accuracy is 9%/100%/55%.

CONCLUSION

GBFN may represent spared liver tissue from alcohol-containing portal venous perfusion due to CVD, which may serve as an adjunctive sign of ALD or alcohol overconsumption with high specificity, but low sensitivity.

Perfusion computed tomography for detection of hepatocellular carcinoma in patients with liver cirrhosis

PURPOSE

To evaluate the diagnostic performance of dynamic perfusion CT (P-CT) for detection of hepatocellular carcinoma (HCC) in the cirrhotic liver.

MATERIALS AND METHODS

Twenty-six cirrhotic patients (19 men, aged 69 ± 10 years) with suspicion of HCC prospectively underwent P-CT of the liver using the 4D spiral-mode (100/80 kV; 150/175mAs/rot) of a dual-source system. Two readers assessed: (1) arterial liver-perfusion (ALP), portal-venous liver-perfusion (PLP) and hepatic perfusion-index (HPI) maps alone; and (2) side-by-side with maximum-intensity-projections of arterial time-points (art-MIP) for detection of HCC using histopathology and imaging follow-up as standard of reference. Another reader quantitatively assessed perfusion maps of detected lesions.

RESULTS

A total of 48 HCCs in 21/26 (81%) patients with a mean size of 20 ± 10 mm were detected by histopathology (9/48, 19%) or imaging follow-up (39/48, 81%). Detection rates (Reader1/Reader2) of HPI maps and side-by-side analysis of HPI combined with arterial MIP were 92/88% and 98/96%, respectively. Positive-predictive values were 63/63% and 68/71%, respectively. A cut-off value of ≥85% HPI and ≥99% HPI yielded a sensitivity and specificity of 100%, respectively, for detection of HCC.

CONCLUSION

P-CT shows a high sensitivity for detection of HCC in the cirrhotic liver. Quantitative assessment has the potential to reduce false-positive findings improving the specificity of HCC diagnosis.

KEY POINTS

• Visual analysis of perfusion maps shows good sensitivity for detection of HCC. • Additional assessment of anatomical arterial MIPs further improves detection rates of HCC. • Quantitative perfusion analysis has the potential to reduce false-positive findings. • In cirrhotic livers, a hepatic-perfusion-index ≥ 9 9% might be specific for HCC.

Pseudolesões hepáticas na ressonância magnética: ensaio iconográfico

A ressonância magnética é uma técnica de grande importância na avaliação do fígado. Assim como na tomografia computadorizada helicoidal, o emprego de aquisições rápidas, em fases diferentes da vascularização hepática, auxilia na detecção e caracterização de tumores. Contudo, algumas armadilhas podem confundir e dificultar a interpretação do exame, simulando lesões parenquimatosas. Estas armadilhas têm forma, localização e características variadas, sendo denominadas de pseudolesões. Podem ser decorrentes de diversos fatores, como alterações perfusionais, esteatose focal, parênquima hepático preservado na esteatose difusa, artefatos, entre outros. É muito importante que sejam reconhecidas, para que não sejam causas de resultados falso-positivos. O objetivo deste ensaio é classificar e ilustrar as diversas pseudolesões hepáticas na ressonância magnética, com breve descrição delas, e alternativas para diferenciá-las das lesões do parênquima.

Effect of prostaglandin E1 on contrast enhanced CT of the liver: statistical analysis during arterial portography

PURPOSE

To determine the diagnostic effect of prostaglandin E(1) on contrast enhancement quality of CT during arterial portography (CTAP).

MATERIALS AND METHODS

Our patients population included 30 patients (11 women, 19 men; age range, 41 approximately 81 years) with liver tumors (23 hepatocellular carcinoma and 7 metastatic liver tumor) who had undergone angiography. We divided the 30 patients, who had undertaken CTAP twice, into two groups at random (group A; n=15, group B; n=15). In group A, first CTAP was performed without prostaglandin E(1). Approximately 5 minutes later, a second CTAP was again initiated 30 seconds after injection of prostaglandin E(1) under the same conditions. In group B, prostaglandin E(1) was injected before the first CTAP only. We measured the mean CT numbers and standard deviation (SD) numbers of anterior, posterior, medial and lateral segments in the liver at the same section of the CTAP using the same size and location of the regions of interest, and these values with and without prostaglandin E(1) were compared.

RESULTS

1) CT numbers: The CT numbers were significantly increased in the medial segment after the injection of prostaglandin E(1) (p<0.05) in all cases of both groups. On the other hand, they were clearly decreased in the posterior segment after the injection of prostaglandin E(1) (p<0.05) in both groups. There were no statistical differences in the CT numbers in the anterior and lateral segments in all patients. In addition, the CT numbers of anterior and posterior segments showed high attenuation compared with the medial and lateral segments in group A without prostaglandin E(1). 2) SD numbers: The SD numbers, which are an index of the homogeneous enhancement, were significantly decreased in the posterior, medial and lateral segments after the injection of prostaglandin E(1) (p<0.01, p<0.05, p<0.01, respectively) in both groups. There were no significant differences in the SD numbers in the anterior segment regardless of the injection of prostaglandin E(1) in all cases.

CONCLUSION

CTAP with injection of prostaglandin E(1) makes contrast enhancement of liver parenchyma more homogeneously than the conventional procedure, and it may be a useful technique for the detection of liver tumors.

Value of intraarterial prostaglandin E(1) injection during CT hepatic arteriography

OBJECTIVE

The purpose of our investigation was to determine if injection of prostaglandin E(1) during CT hepatic arteriography could help physicians to distinguish tumors from nonportal venous flow-related pseudolesions in the region of the gallbladder fossa.

SUBJECTS AND METHODS

In 34 patients who underwent CT during arterial portography to detect liver tumors, CT hepatic arteriography was performed before and after prostaglandin E(1) injection via the superior mesenteric artery. Between each study, an interval of 10 minutes was set. On CT hepatic arteriogram obtained 15 to 20 sec after prostaglandin E(1) injection, we distinguished changes in the size and shape of pseudolesions in the liver around the gallbladder as well as those of 42 tumorous lesions. In addition, we measured the change in CT attenuation of pseudolesions.

RESULTS

The size of the enhanced area of pseudolesions visible on CT hepatic arteriography decreased in 69% (25/36) of the pseudolesions after intraarterial prostaglandin E(1) injection, with the mean diameter diminishing from 14.1 mm to 8.8 mm. Notably, in 11 pseudolesions, the enhanced area disappeared. In 86% (31/36), the CT attenuation decreased with the mean attenuation, diminishing from 211.3 H to 163.8 H. However, the size and shape of the enhanced area of tumorous lesions did not change.

CONCLUSION

The hemodynamic features of pseudolesions on angiographically assisted helical CT scans caused by cholecystic venous inflow are easily influenced by increased portal venous flow. Consequently, pseudolesions around the gallbladder usually can be distinguished from tumorous lesions by adding prostaglandin E(1) injection via the superior mesenteric artery during CT hepatic arteriography.

Non-tumorous enhancement caused by cholecystic venous inflow shown on biphasic CT hepatic arteriography: comparison with hepatocellular carcinoma

The haemodynamics in non-tumorous abnormalities on CT arterial portography (CTAP) owing to cholecystic venous direct inflow to the liver were compared with the haemodynamics in hepatocellular carcinoma. 53 patients who simultaneously underwent CTAP and CT during hepatic arteriography (CTHA) to detect hepatocellular carcinoma had the late phase added to CTHA. Changes in size, shape and pattern of 47 non-tumorous enhancement abnormalities on the liver around the gall bladder or in the dorsum of segment IV between the early and late phases on biphasic CTHA as well as of 60 tumorous lesions were determined. Enhancement on biphasic CTHA was seen in all 47 lesions with a non-tumorous portal defect (early phase alone, n=8; late phase alone, n = 3; both, n = 36). In these 47 lesions, the size and the shape of enhancement changed in 63.8% and 51.1%, respectively, between the early and late phases on CTHA; the pattern of enhancement did not change in 72.3%. On the other hand, the size of enhancement on biphasic CTHA changed in only 16.7% of 60 tumours, and the shape in only 5%, although the enhancement pattern changed in a large proportion (80%). In conclusion, owing to the difference in haemodynamics, non-tumorous abnormalities caused by cholecystic venous inflow and tumours are clearly delineated on biphasic CTHA. Thus, adding the late phase to previous single phase CTHA (i.e. performing biphasic CTHA) is useful in differentiating the two entities.

The aetiology of non-tumorous enhancement in the hepatic hilum shown on CT hepatic arteriography

The causes of non-tumorous abnormalities in the hepatic hilum seen on CT hepatic arteriography were investigated. 13 patients with non-tumorous defects of portal perfusion in the hepatic hilum on CT arterial portography underwent both CT hepatic arteriography from the common hepatic artery and CT obtained during proper hepatic arteriography. The findings of non-tumorous portal defects on these two angiographic studies using helical CT were compared. In the 13 patients, 14 non-tumorous defects of portal perfusion in the hepatic hilum on CT arterial portography were detected as enhanced areas in 10 regions (dorsum of segment IV, 7/10; dorsum of the lateral segment, 3/4) on CT hepatic arteriography via the common hepatic artery, but none were enhanced on CT obtained during proper hepatic arteriography. In conclusion, the main cause of non-tumorous enhancement in the hepatic hilum seen on CT hepatic arteriography is non-portal direct inflow via the parabiliary venous system.

Aberrant left gastric vein demonstrated by helical CT

PURPOSE

Our goal was to describe the CT findings of aberrant left gastric vein (ALGV) and to evaluate the clinical significance of this vein.

METHOD

Four patients in whom ALGVs were demonstrated by helical CT were examined. Each patient had either intrahepatic cholangiocarcinoma, cirrhosis with gastric varices, chronic hepatitis, or nonspecific abdominal pain. All patients underwent two phase helical CT, and the patient with cholangiocarcinoma underwent CT during arterial portography, and 3D images of the abdominal veins were obtained.

RESULTS

In all patients, the ALGVs ran along the hepatogastric ligament and were directly connected with the left portal branch. In the patient with cholangiocarcinoma, the portal vein had severe stenosis by tumor invasion, and both the ALGV and the aberrant right gastric vein functioned as a collateral pathway of the portal flow into the liver. In the patient with cirrhosis, dilated ALGV with hepatofugal flow caused gastric varices.

CONCLUSION

The ALGV is directly connected with the left portal branch and may play an important role in the collateral pathway of the portal system.