Enlargement of the hepatic artery is present in dogs with a congenital extrahepatic portosystemic shunt and is independent of shunt insertion into the systemic circulation.

The accurate diagnosis of portovascular anomalies has been facilitated by improvements in diagnostic imaging technology. In humans, hepatic arterial blood flow changes in response to the reduction in portal blood flow. The hepatic arterial buffer response characterizes an intrinsic regulatory mechanism in response to reduced portal venous blood flow, which results in hepatic arterial enlargement. At the authors' institution, enlargement of the hepatic artery has been anecdotally observed in a population of dogs with extrahepatic portosystemic shunting, consistent with previous literature that documents variability in hepatic arterial size. In this retrospective, blinded, analytical study, a hepatic artery:aorta (Ha:Ao) ratio was assessed on CT studies from 112 dogs, with (n = 43) and without (n = 69) an extrahepatic congenital portosystemic shunt in order to compare the hepatic artery size independent of body weight between the two populations. A significant increase in the Ha:Ao ratio was documented in dogs with an extrahepatic portosystemic shunt (EHPSS) compared with those dogs with no EHPSS independent of the location of shunt insertion into the systemic circulation (P < .001). Three cases had repeat CT after surgery, and all had Ha:Ao ratio reductions following treatment. The authors propose that this may be an additional imaging feature observed in dogs with an EHPSS.

Computed tomographic measures of renomegaly vary among dogs with different types of congenital portosystemic shunts.

Renomegaly has been reported in dogs with congenital portosystemic shunts (PSS). However, no study has objectively evaluated the degree of renomegaly in dogs with different types of PSS. The purpose of this retrospective, analytical, cross-sectional study was to determine kidney size (renal length-to-L2 vertebral body ratio; RL/L2 ratio) using CT in dogs with different types of PSS and correlate with clinical information. A medical record search for dogs with a PSS diagnosed using CT between 2016 and 2020 was conducted. Breed, age, sex, body weight, and biochemistry results were recorded. Kidney and L2 vertebral body lengths were measured using multiplanar reformatted CT images, and the RL/L2 ratio was calculated. Dogs were categorized into four groups based on PSS morphology for comparisons: intrahepatic (IH; n = 19), extrahepatic portocaval (EHPC; n = 20), extrahepatic portoazygos (EHPA; n = 7), or extrahepatic portophrenic (EHPP, n = 7). The RL/L2 ratio (mean ± SD) was largest in IH (3.55 ± 0.38) and EHPC (3.55 ± 0.38), followed by EHPP (3.10 ± 0.23), and EHPA (2.78 ± 0.18). RL/L2 ratio was significantly larger in EHPC and IH (vs. EHPA and EHPP [P < .01]). Significant correlations between kidney size and creatinine, alkaline phosphatase, albumin, total protein, and ammonia were present. Renomegaly was observed in 86.8% of dogs with PSS overall, but it was uncommon in dogs with EHPA and less common in dogs with EHPP, as these two groups showed clinical signs later in life, made evident by older age at presentation. The authors suggest that the severity of hepatic dysfunction and the shunted blood volume may influence the development of renomegaly in dogs with PSS.

Percutaneous transvenous coil embolization (PTCE) for treatment of single extrahepatic portosystemic shunt in dogs.

BACKGROUND: There is limited information regarding percutaneous transvenous coil embolization (PTCE) for single extrahepatic portosystemic shunt (PSS). This study aimed to describe the procedure and outcome of PTCE in dogs with a single extrahepatic PSS. Forty-two privately owned dogs were included in this study. All dogs were diagnosed with extrahepatic PSS by computed tomography (CT). Preoperative CT images were used to evaluate the diameter of the PSS for coil placement. A multipurpose balloon catheter was percutaneously inserted into the PSS via the jugular vein, and transvenous retrograde portography (TRP) and measurement of blood pressure in the PSS (pPSS) were performed during balloon inflation; one or more embolization coils were implanted via the catheter. RESULTS: In most cases, preoperative median fasting and postprandial serum total bile acid (TBA) concentrations were high (fasting, 86.5 µmol/L [ 3.7-250.0 µmol/L]; postprandial, 165.5 µmol/L [ 1.5-565.0 µmol/L]). CT revealed that 30 dogs had left gastrophrenic shunt; eight had left gastroazygos shunt; and one each had left gastrocaval, splenocaval, splenophrenic, and left colocaval shunt. TRP revealed that intrahepatic portal vascularity was clearly detectable in all dogs. The median values of pPSS before and during the balloon occlusion were 4.8 mmHg [2.0-13.0 mmHg] and 8.6 mmHg [5.0-18.0 mmHg], respectively. The median number and diameter of coils used were 2 coils [1 - 5 coils] and 8.0 mm [4.0 - 12.0 mm], respectively. The median times of irradiation and PTCE were 9 min [4-26 min] and 40 min [23-75 min], respectively. The median fasting and postprandial TBAs significantly decreased to 8.2 µmol/L [0.3-45.1 µmol/L, n = 38, p = 0.0028] and 19.8 µmol/L [0.3-106.7 µmol/L, n = 38, p = 0.0018], respectively, approximately 1 month after PTCE. The clinical success rate of PTCE without requirement for a second surgery was 95.2% (40/42 dogs). During revision surgery, one dog underwent surgical ligation and, in another dog, an ameroid constrictor was placed. CONCLUSIONS: PTCE was clinically effective in treating single extrahepatic PSS in dogs. Preoperative CT and TRP prior to PTCE might be clinically valuable for choosing the size of embolization coils, deciding the appropriate location of coil implantation, and estimating the number of coils to be implanted. PTCE is a promising alternative to conventional surgical procedures for single extrahepatic PSS in dogs.

Intramural esophageal location of a portosystemic shunt in a dog with two congenital portosystemic shunts on CT angiography.

A 5-year-old male neutered pug with hematuria was presented to a referral hospital after identification of an extrahepatic portosystemic shunt (EHPSS) during abdominal ultrasonography. Computed tomographic-angiography revealed two anomalous blood vessels (left gastroazygous and left gastrophrenic). The left gastroazygous vessel followed an atypical path within the dorsolateral esophageal wall before entering the azygous vein. The morphology of this highly unusual vessel has not, based on the authors' review of the literature, been previously reported. In combination with a second anomalous vessel, this resulted in a unique presentation of an EHPSS. Computed tomography-angiography was essential for diagnosis and surgical planning in this case.

Congenital portopulmonary shunt in a cat.

A 9-year-old spayed female crossbreed cat with chief complaints of anorexia and hypersalivation had high serum concentrations of ammonia and fasting and postprandial total bile acid. Therefore, she was referred to our hospital. On the first evaluation, haematology, serum chemistry, radiography and ultrasonography findings suggested that she had a congenital portosystemic shunt. CT revealed a shunt vessel from the left gastric vein to the left pulmonary vein. During median celiotomy and sternotomy, gross findings and mesenteric portography revealed abnormal vessel shunting from the left gastric vein to the left pulmonary vein. Complete ligation of the shunt vessel was achieved. She recovered without any complications. Postoperative serum chemistry revealed that ammonia and total bile acid levels decreased to within the reference intervals. This report is the first to describe the clinical features and surgical outcome of a cat with a congenital portopulmonary shunt.

Perceptions of porta-celiac vascular models for hepatic surgery and their use in residency training.

BACKGROUND: Primary aspect of hepatic navigation surgery is the identification of source vascular details to preserve healthy liver which has a vascular anatomy quite challenging for the young surgeons. The purpose was to determine whether three-dimensional (3D) vascular pattern models of preoperative computed tomography (CT) images will assist resident-level trainees for hepatic surgery. METHODS: This study was based on the perception of residents who were presented with 5 different hepatic source vascular patterns and required to compare their perception level of CT, and 1:1 models in terms of importance of variability, differential of patterns and preoperative planning. RESULTS: All residents agree that models provided better understanding of vascular source and improved preplanning. Five stations provided qualitative assessment with results showing the usefulness of porta-celiac models when used as anatomical tools in preplanning (p = 0.04), simulation of interventional procedures (p = 0.02), surgical education (p = 0.01). None of the cases had scored less than 8.5. Responses related to understanding variations were significantly higher in the perception of the 3D model in all cases, furthermore 3D models were more useful for seniors in more complex cases 3 and 5. Some open-ended answers: "The 3D model can completely change the operation plan" One of the major factors for anatomical resection of liver transplantation is the positional relationship between the hepatic arteries and the portal veins. CONCLUSION: The plastic-like material presenting the hepatic vascularity enables the visualization of the origin, pattern, shape, and angle of the branches with appropriate spatial perception thus making it well-structured.

Classification of portosystemic shunts entering the caudal vena cava at the omental foramen in dogs.

OBJECTIVE: To re-evaluate the anatomy and classification of congenital extrahepatic portosystemic shunts entering the caudal vena cava at the level of the omental foramen. MATERIAL AND METHODS: A retrospective review of a consecutive series of dogs undergoing CT angiography as part of the diagnostic work-up for a congenital extrahepatic portosystemic shunt. RESULTS: In total, 53 dogs met the inclusion criteria revealing four anatomically distinct omental foramen shunt types; one of which (32 of 53 dogs) showed no shunting blood flow through the right gastric vein and three of which (21 of 53 dogs) involved shunting flow through this vessel. The anatomy of these four distinct shunt types, as defined by CT angiography, was found to be highly consistent. In all cases, regardless of the tributary vessels, the left gastric vein was the final vessel that communicated with the caudal vena cava. Using these findings, a more accurate naming classification for congenital portosystemic shunts entering the caudal vena cava at the level of the omental foramen was proposed. CLINICAL SIGNIFICANCE: A precise pre-treatment anatomical classification of congenital extrahepatic portosystemic shunts entering the caudal vena cava at the level of the omental foramen is important for a more complete understanding of the severity of clinical signs and prognosis, and for the better communication between clinicians and researchers in this clinical field.

Predictive value of perfusion CT for blood loss in liver resection.

Blood loss is associated with the degree of damage in liver stiffness. Severe liver steatosis is a matter of concern in liver surgery, but does not correlate with liver stiffness. This study aimed to assess the relationship between blood perfusion of the liver and blood loss in liver pathologies. Data from elective liver resection for liver cancer were analyzed. All patients underwent preoperative assessments including perfusion CT. Patients were divided into 4 groups in accordance with the pathological background of liver parenchyma. Relationships between portal flow as assessed by perfusion CT and perioperative variables were compared. Factors correlating with blood loss were analyzed. In 166 patients, portal flow from perfusion CT correlated positively with platelet count and negatively with indocyanine green retention rate at 15 min. Background liver pathology was normal liver (NL) in 43 cases, chronic hepatitis (CH) in 56, liver cirrhosis (LC) in 42, and liver steatosis (LS) in 25. Rates of hepatitis viral infection and pathological hepatocellular carcinoma were more frequent in LC and CH groups than in the other groups (p < 0.05). LC and LS showed significantly worse liver function than the NL and CH groups. Portal flow from perfusion CT correlated positively with damage to liver parenchyma and negatively with blood loss at liver transection. Low portal flow on perfusion CT predicts blood loss during liver transection.

Intrahepatic veno-venous collateralization and misrepresentative hepatic venous pressure gradients in children.

BACKGROUND: Accurate and reproducible means of measuring the portosystemic gradient are essential for risk stratification and treatment of portal hypertension. OBJECTIVE: To report the reliability of hepatic venous pressure gradients in children with intrahepatic veno-venous collateralization. MATERIALS AND METHODS: Between January 2012 and December 2019 (96 months), 39 patients with native livers underwent wedge hepatic venography and hepatic venous pressure gradient measurements at a tertiary pediatric center. All archived images were reviewed for balloon isolation of the hepatic vein and hepatic vein-to-hepatic vein (HV-HV) collaterals. HV-HV collaterals were categorized as present on the basis of non-catheterized segmental venous opacification despite appropriate balloon isolation. Hepatic venous pressure gradient was defined as the difference of wedge and free hepatic venous pressures. Wedge portosystemic gradient was defined as the difference between wedge hepatic venous pressure and right atrial (RA) pressures. For patients subsequently undergoing portal venous catheterization, portosystemic gradient was defined as the difference between main portal vein and RA pressures. RESULTS: Thirteen of 39 (33.3%) patients demonstrated HV-HV collaterals on wedge hepatic venography. The mean hepatic venous pressure gradient was 5.2±3.8 mmHg (range: 0-15 mmHg). The mean hepatic venous pressure gradient was 3.6±2.6 mmHg (range: 0-9 mmHg) in the presence of HV-HV collaterals and 5.9±4.2 mmHg (range: 1-15 mmHg) in the absence of HV-HV collaterals (P=0.043). Twelve (30.8%) patients were found to have varices: 10 gastroesophageal, 1 rectal and 1 stomal. The mean hepatic venous pressure gradient in patients with varices was 5.4±47 mmHg (range: 0-15 mmHg). For patients with varices, mean hepatic venous pressure gradient was 3.0±2.7 mmHg (range: 0-9 mmHg) in the presence of HV-HV collaterals and 10.3±4.1 mmHg (range: 5-15 mmHg) in the absence of HV-HV collaterals (P=0.004). Four (10.3%) patients had extrahepatic portal vein occlusion: 3 with cavernous transformation and 1 with type Ib Abernethy malformation. All patients with extrahepatic portal vein occlusion demonstrated HV-HV collaterals compared with 8 of 35 (22.9%) patients without extrahepatic portal vein occlusion (P=0.002). Four of 39 (10.3%) patients underwent direct portal pressure measurements: 3 via transhepatic and 1 via trans-splenic portal access. All had demonstrated HV-HV collaterals on wedged imaging. One had extrahepatic portal vein occlusion. The mean time between wedge portosystemic gradient and portosystemic gradient measurement was 3.75 days (range: 0-8 days). The mean wedge portosystemic gradient was 4.5±3.1 mmHg (range: 2-9 mmHg) and the mean portosystemic gradient was 14.5±3.7 mmHg (range: 12-20 mmHg) (P=0.006). CONCLUSION: HV-HV collateralization is frequently observed in children undergoing wedged portal venography and leads to misrepresentative hepatic venous pressure gradients. All patients undergoing hepatic venous pressure gradient measurement should have wedged venography to identify HV-HV collaterals and to qualify measured pressures. Additional techniques to obtain representative pressures in the presence of HV-HV collaterals warrant further investigation.

Periportal Plexiform Neurofibromatosis; a rare intra-abdominal manifestation of NF1.

Periportal Plexiform Neurofibromatosis (PPNF) is a rare visceral manifestation of Neurofibromatosis Type 1 (NF1) or Von Recklinghausen disease. Neurofibromas are the most common lesions in NF1. We present a case of a young female diagnosed with NF1 who initially presented with hard abdominal mass. Contrast enhanced CT revealed the unusual lintrahepatic periportal plexiform neurofibromatosis in addition to a typical large retroperitoneal lumbar neurofibroma.

Application of CT-based radiomics in predicting portal pressure and patient outcome in portal hypertension.

PURPOSE: Portal venous pressure (PVP) measurement is of clinical significance, especially in patients with portal hypertension. However, the invasive nature and associated complications limits its application. The aim of the study is to propose a noninvasive predictive model of PVP values based on CT-extracted radiomic features. METHODS: Radiomics PVP (rPVP) models based on liver, spleen and combined features were established on an experimental cohort of 169 subjects. Radiomics features were extracted from each ROI and reduced via the LASSO regression to achieve an optimal predictive formula. A validation cohort of 62 patients treated for gastroesophageal varices (GOV) was used to confirm the utility of rPVP in predicting variceal recurrence. The association between rPVP and response to treatment was observed. RESULTS: Three separate predictive formula for PVP were derived from radiomics features. rPVP was significantly correlated to patient response to endoscopic treatment for GOV. Among which, the model containing both liver and spleen features has the highest predictability of variceal recurrence, with an optimal cut-off value at 29.102 mmHg (AUC 0.866). A Kaplan Meier analysis further confirmed the difference between patients with varying rPVP values. CONCLUSION: PVP values can be accurately predicted by a non-invasive, CT derived radiomics model. rPVP serves as a non-invasive and precise reference for predicting treatment outcome for GOV secondary to portal hypertension.

Non-cirrhotic Extra-Hepatic Porto-Systemic Shunt Causing Adult-Onset Encephalopathy Treated with Endovascular Closure.

INTRODUCTION: Encephalopathy secondary to hyperammonemia due to Congenital Extra-hepatic Porto-systemic shunt (CEPS) in the absence of liver cirrhosis is an exceptionally unusual condition. We describe the case of a 54-year-old woman admitted to the Emergency Department complaining of recurrent episodes of confusion and worsening cognitive impairment. At admission, the patient displayed slowing cognitive-motor skills with marked static ataxia and impaired gait. Hyperammonemia was detected in the serum. An abdominal computed tomography (CT) excluded portal hypertension and liver cirrhosis, detecting a congenital extra-hepatic porto-systemic shunt which is a highly unusual vascular malformation. The patient was treated by interventional radiologists with a successful endovascular closure. AREAS COVERED: We have performed a review of the last three decades of the literature, starting from the introduction of CT scanning in common clinical practice. Eighteen studies (case reports) described 29 patients with encephalopathy secondary to hyperammonemia due to CEPS in the absence of liver cirrhosis: They underwent treatment similar to our case report of CEPS. EXPERT COMMENTARY: Encephalopathy secondary to hyperammonemia in the absence of hepatic dysfunction is an important diagnostic dilemma to many clinicians. An interventional radiologic approach is currently preferred.

Blood flow of the venous system during resuscitative endovascular balloon occlusion of the aorta: Noninvasive evaluation using phase contrast magnetic resonance imaging.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a viable resuscitation approach for a subdiaphragmatic injury that can regulate arterial blood flow. On the other hand, the evaluation of venous or portal venous blood flow during REBOA remains insufficient because invasive cannulation or exposure of the vessel may affect the blood flow, and Doppler echography is highly operator-dependent. However, phase contrast magnetic resonance imaging has enabled accurate evaluation and noninvasive measurement. This study aimed to investigate the change of venous and portal venous blood flow during REBOA in a porcine model. METHODS: Seven pigs were anesthetized, and a REBOA catheter was placed. The blood flows of the inferior vena cava (IVC), hepatic vein (HV), portal vein (PV), and superior vena cava (SVC) were measured using phase contrast magnetic resonance imaging, in both the balloon deflated (no-REBOA) and fully balloon inflated (REBOA) states. Mean arterial pressure (MAP), central venous pressure, cardiac index, and systemic vascular resistance index were measured. RESULTS: The blood flows of the suprahepatic, infrahepatic, and distal IVC, HV, and PV in the no-REBOA state were 1.40 ± 0.36 L·min, 0.94 ± 0.16 L·min, 0.50 ± 0.19 L·min, 0.060 ± 0.018 L·min, and 0.32 ± 0.091 L·min, respectively. The blood flow of each section in the REBOA condition was significantly decreased at 0.41 ± 0.078 (33% of baseline), 0.15 ± 0.13 (15%), 0.043 ± 0.034 (9%), 0.029 ± 0.017 (37%), and 0.070 ± 0.034 L·min (21%), respectively. The blood flow of the SVC increased significantly in the REBOA condition (1.4 ± 0.63 L·min vs. 0.53 ± 0.14 L·min [257%]). Mean arterial pressure, central venous pressure, cardiac index, and systemic vascular resistance index were significantly increased after REBOA inflation. CONCLUSION: Resuscitative endovascular balloon occlusion of the aorta decreased blood flows of the IVC, HV, and PV and increased blood flow of the SVC. This result could be explained by the collateral flow from the lower body to the SVC. A better understanding of the effect of REBOA on the venous and portal venous systems may help control liver injury.

Diagnostic accuracy of multi-slice computed tomography in children with Abernethy malformation.

BACKGROUND: Abernethy malformation is a rare congenital abnormality. Imaging examination is an important method for the diagnosis. The purpose of this study was to demonstrate manifestations of multi-slice computed tomography (MSCT) in Abernethy malformation and its diagnostic accuracy. METHODS: Fourteen children with Abernethy malformation were admitted to our center in China between July 2011 and January 2018. All 14 patients (eight males and six females) received MSCT and digital subtraction angiography (DSA) while eight patients also received ultrasound. The patients' age ranged from 1 to 14 (median age 8 years old). The clinical records of the patients were retrospectively reviewed. MSCT raw data were transferred to an Advantage Windows 4.2 or 4.6 workstation (General Electric Medical Systems, Waukesha, WI). We compared the findings of MSCT with DSA and surgical results in order to ascertain diagnostic accuracy. RESULTS: Three cases had type Ib Abernethy malformation and eleven cases had type II. Two cases of type II Abernethy malformation were misdiagnosed as type Ib using MSCT. Comparing the findings of MSCT with DSA and surgical results, the accuracy of MSCT was 85.7% (12/14), in which 100.0% (3/3) were type Ib and 81.8% (9/11) were type II. Clinical information included congenital heart disease, pulmonary hypertension, diffuse pulmonary arteriovenous fistula, abnormal liver function, hepatic nodules, elevated blood ammonia, and hepatic encephalopathy. Eleven cases were treated after diagnosis. One patient with Abernethy malformation type Ib (1/3) underwent liver transplantation. Seven patients with Abernethy malformation type II (7/11) were treated by shunt occlusion, received laparoscopy, or were treated with open surgical ligation. Another three patients (3/11) with Abernethy malformation type II were treated by interventional portocaval shunt occlusion under DSA. CONCLUSION: MSCT attains excellent capability in diagnosing type II Abernethy malformation and further shows the location of the portocaval shunt. DSA can help when it is hard to determine diagnosis between Abernethy type Ib and II using MSCT.

Platelet's Rule of Change and Clinical Significance before and after Splenectomy.

Portal vein system thrombosis (PVST) is a form of venous thrombosis, which behaves as a common and potentially life-threatening complication after splenectomy. Numerous studies have been made to investigate the mechanism and the risk factors of PVST. However, the research on the prevention and treatment of PVST associated with platelet's (PLT) rule of change is rare. This work mainly investigates the PLT's rule of change and its correlativity with the formation of PVST after splenectomy. The retrospective study included 117 patients who underwent splenectomy from August 2014 to June 2018 and monitored by blood routine, D-dimer (D-D), and portal vein system ultrasound routinely after splenectomy. The changes of PLT and D-D were recorded and compared before and after each operation. We analyzed the changes of PLT and D-D as well as the incidence of PVST postoperatively. Most of the patients' PLT increased significantly after splenectomy. On the first day after operation, there were 80 patients' (68.38%) PLT recovered to normal or above normal. The proportion of patients with abnormally high PLT value on the seventh and fourteenth day were 60.68 per cent and 81.20 per cent, respectively. Thereinto, there were 67 patients' (57.26%) PLT beyond 500 × 109/L on the 14th day. The D-D of all patients exceeded the normal range on the first, seventh, and fourteenth day after operation, and the difference was statistically significant (P < 0.05), which behaved similar like PLT. Meanwhile, our color Doppler ultrasonography showed that the incidence of PVST was 70.79 per cent. Among the patients with PVST, 82 (100%) patients' PLT was increased after operation. The PLT of patients increased obviously after splenectomy. The increased blood viscosity caused by the consecutive elevation of PLT may result in a higher PVST incidence. Early intervention and treatment are needed clinically for PVST after splenectomy.