3D mesenteric angiogram-based assessment of Arc of Riolan crossing the inferior mesenteric vein: important considerations in high ligation during splenic flexure takedown in anterior resection.

BACKGROUND: Recent studies have described the finding of the Arc of Riolan (AoR) crossing the inferior mesenteric vein (IMV) seen during high ligation of IMV while performing minimally invasive colectomies. However, the AoR usually has a medial course, and this variant AoR anatomic course and the clinical importance of its preservation during splenic flexure takedown in anterior resection remains controversial. METHODS: After institutional approval (QA-5775), radiological identification of and mapping of the vessel horizontally crossing the IMV under the pancreas, when present, was performed at a single institution (Westmead Hospital, New South Wales, Australia). One hundred consecutive computed tomographic (CT) mesenteric angiograms conducted in 2018 were reviewed retrospectively to determine the presence of a vessel horizontally crossing the IMV. 3D reconstructions were used to map out its course to understand its origin and full course. Baseline characteristics, including demographic and comorbidity data, were obtained from the medical record. RESULTS: On 3D mesenteric angiogram reconstructions, a vessel crossing anterior to the IMV was present in 11 of 98 cases (11.2%). Two cases were excluded as the presence of this vessel was indeterminate. Eight of 11 patients (72.7%) were male, and the mean age was 49.3 years (range: 21-80 years). There was no statistically significant difference in age and comorbidities between the groups. Importantly, in all 11 cases, there was an arterial vessel crossing the IMV originating from the SMA and communicating with the IMA or a branch of the IMA, proving definitively that this vessel was by definition the AoR. CONCLUSION: This 3D mesenteric angiogram mapping study has shown definitively that the vessel horizontally crossing anterior to the IMV and inferior to the pancreas is an arterial vessel from the SMA to IMA, and by definition the Arc of Riolan. When present, identification and preservation of this collateral arterial vessel during splenic flexure takedown in anterior resection may be important in reducing the risk of post-operative bowel ischaemia.

Surgical management and pathological assessment of pancreatoduodenectomy with venous resection: an international survey among surgeons and pathologists.

BACKGROUND: The aim of this survey was to gain insights in the current surgical management and pathological assessment of pancreatoduodenectomy with portal-superior mesenteric vein resection (VR). METHODS: A systematic literature search was performed to identify international expert surgeons (N = 150) and pathologists (N = 40) who published relevant studies between 2009 and 2019. These experts and Dutch surgeons (N = 17) and pathologists (N = 20) were approached to complete an online survey. RESULTS: Overall, 76 (46%) surgeons and 37 (62%) pathologists completed the survey. Most surgeons (71%) estimated that preoperative imaging corresponded correctly with intraoperative findings of venous involvement in 50-75% of patients. An increased complication risk following VR was expected by 55% of surgeons, mainly after Type 4 (segmental resection-venous conduit anastomosis). Most surgeons (61%) preferred Type 3 (segmental resection-primary anastomosis). Most surgeons (75%) always perform the VR themselves. Standard postoperative imaging for patency control was performed by 54% of surgeons and 39% adjusted thromboprophylaxis following VR. Most pathologists (76%) always assessed tumor infiltration in the resected vein and only 54% of pathologists always assess the resection margins of the vein itself. Variation in assessment of tumor infiltration depth was observed. CONCLUSION: This international survey showed variation in the surgical management and pathological assessment of pancreatoduodenectomy with venous involvement. This highlights the lack of evidence and emphasizes the need for research on imaging modalities to improve patient selection for VR, surgical techniques, postoperative management and standardization of the pathological assessment.

Usefulness of three-dimensional printing of superior mesenteric vessels in right hemicolon cancer surgery.

The anatomy of the superior mesenteric vessels is complex, yet important, for right-sided colorectal surgery. The usefulness of three-dimensional (3D) printing of these vessels in right hemicolon cancer surgery has rarely been reported. In this prospective clinical study, 61 patients who received laparoscopic surgery for right hemicolon cancer were preoperatively randomized into 3 groups: 3D-printing (20 patients), 3D-image (19 patients), and control (22 patients) groups. Surgery duration, bleeding volume, and number of lymph node dissections were designed to be the primary end points, whereas postoperative complications, post-operative flatus recovery time, duration of hospitalization, patient satisfaction, and medical expenses were designed to be secondary end points. To reduce the influence of including different surgeons in the study, the surgical team was divided into 2 groups based on surgical experience. The duration of surgery for the 3D-printing and 3D-image groups was significantly reduced (138.4 ± 19.5 and 154.7 ± 25.9 min vs. 177.6 ± 24.4 min, P = 0.000 and P = 0.006), while the number of lymph node dissections for the these 2 groups was significantly increased (19.1 ± 3.8 and 17.6 ± 3.9 vs. 15.8 ± 3.0, P = 0.001 and P = 0.024) compared to the control group. Meanwhile, the bleeding volume for the 3D-printing group was significantly reduced compared to the control group (75.8 ± 30.4 mL vs. 120.9 ± 39.1 mL, P = 0.000). Moreover, patients in the 3D-printing group reported increased satisfaction in terms of effective communication compared to those in the 3D-image and control groups. Medical expenses decreased by 6.74% after the use of 3D-printing technology. Our results show that 3D-printing technology could reduce the duration of surgery and total bleeding volume and increase the number of lymph node dissections. 3D-printing technology may be more helpful for novice surgeons.Trial registration: Chinese Clinical Trial Registry, ChiCTR1800017161. Registered on 15 July 2018.

Does mesenteric venous imaging assessment accurately predict pathologic invasion in localized pancreatic ductal adenocarcinoma?

BACKGROUND: Accurate prediction of mesenteric venous involvement in pancreatic ductal adenocarcinoma (PDAC) is necessary for adequate staging and treatment. METHODS: A retrospective cohort study was conducted in PDAC patients at a single institution. All patients with resected PDAC and staging CT and EUS between 2003 and 2014 were included and sub-divided into "upfront resected" and "neoadjuvant chemotherapy (NAC)" groups. Independent imaging re-review was correlated to venous resection and venous invasion. Sensitivity, specificity, positive and negative predictive values were then calculated. RESULTS: A total of 109 patients underwent analysis, 60 received upfront resection, and 49 NAC. Venous resection (30%) and vein invasion (13%) was less common in patients resected upfront than those who received NAC (53% and 16%, respectively). Both CT and EUS had poor sensitivity (14-44%) but high specificity (75-95%) for detecting venous resection and vein invasion in patients resected upfront, whereas sensitivity was high (84-100%) and specificity was low (27-44%) after NAC. CONCLUSIONS: Preoperative CT and EUS in PDAC have similar efficacy but different predictive capacity in assessing mesenteric venous involvement depending on whether patients are resected upfront or received NAC. Both modalities appear to significantly overestimate true vascular involvement and should be interpreted in the appropriate clinical context.

Assessment of the inferior mesenteric vein diameter as a surrogate marker to evaluate response to neoadjuvant chemoradiotherapy for locally advanced rectal adenocarcinoma.

AIM: Neoadjuvant chemoradiotherapy for locally advanced rectal cancer aims to downstage prior to definitive management. Repeat imaging assessment of the tumour post-therapy has implications for treatment. Our aim was to assess if the inferior mesenteric vein (IMV) diameter measured on CT can be used as a surrogate marker for evaluation of tumour response to neoadjuvant treatment. METHOD: IMV diameter was assessed in patients with and without locally advanced rectal cancer, pre- and post-radiotherapy, to ascertain if IMV diameter is a surrogate marker of tumour response. RESULTS: IMV diameter was 5.9 mm in patients with rectal cancer vs 4.7 mm in patients without (P = 0.0001). The baseline IMV diameter was significantly higher for cases with local lymphadenopathy [N0 5.2 mm vs N1/2 6 mm (P = 0.0059)] and extramural venous invasion (EMVI) [negative 5.4 mm vs positive 6.4 mm (P = 0.0001)]. Post-radiotherapy there was a significant decrease in the IMV diameter in cases with treatment response compared to non-responders: the percentage change in IMV diameter was a 17.54% decrease vs 1.39% increase (P = 0.0001). These results were reproduced on comparing between magnetic resonance tumour regression grades using ANOVA (P = 0.0001). There was also a significant decrease in IMV diameter when assessing lymph node (LN) and EMVI response vs non-responders (P = 0.0001 and 0.0001 respectively). CONCLUSION: Patients with rectal cancer have a dilated IMV compared with patients without rectal cancer. We confirm that IMV diameter is a potential surrogate marker of LN status and EMVI at baseline. IMV diameter is also a marker of tumour, LN and EMVI response to chemoradiotherapy.

Assessment of surgical resectability of pancreatic adenocarcinomas with multidetector computed tomography: what are the possibilities and problems?

BACKGROUND/AIMS: To investigate the accuracy of multidetector computed tomography (MDCT) in preoperatively determining the surgical resectability of pancreatic adenocarcinomas. MATERIALS AND METHODS: Multidetector computed tomography, surgery, and pathological results of 274 patients with pancreatic adenocarcinoma were evaluated retrospectively. MDCT findings were compared with surgical and pathological findings to determine the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of MDCT in determining surgical resectability. RESULTS: A total of 124 of 274 (56%) patients (83 males, mean age: 60 years) underwent laparoscopy and/or laparotomy. The sensitivity, specificity, PPV, NPV, and accuracy of MDCT in determining the surgical resectability of pancreatic adenocarcinomas were 100%, 72%, 78%, 100%, and 86%, respectively. Liver metastases in 9 cases, peritoneal metastases in 3 cases, and vascular invasion in 5 cases, which were determined during surgery, were not reported by MDCT. On re-review of the MDCT images of these 17 patients, no metastatic lesions could be seen in 9 patients with liver metastases and in 2 of 3 patients with peritoneal metastases. In 1 patient, a peritoneal implant of a diameter of 8 mm was missed on MDCT. There was no vascular invasion according to Lu criteria on the MDCT images in the 5 cases that had vascular invasion in the surgical exploration. CONCLUSION: The accuracy of MDCT is high in the preoperative determination of surgical resectability of pancreatic adenocarcinomas, but the detection of small liver and peritoneal metastases and accurate determination of vascular invasion are still major problems. Surgeons should be aware of the limitations of preoperative MDCT.

Initial transcatheter thrombolysis for acute superior mesenteric venous thrombosis.

AIM: To determine the optimal initial treatment modality for acute superior mesenteric vein thrombosis (ASMVT) in patients with circumscribed peritonitis. METHODS: A retrospective review was made of the Vascular Surgery Department's medical records to identify adult patients (≥ 18 years old) presenting with circumscribed peritonitis and diagnosed with ASMVT by imaging or endoscopic examination. Patients were selected from the time period between October 2009 and October 2012 to assess the overall performance of a new first-line treatment policy implemented in May 2011 for patients with circumscribed peritonitis, which recommends transcatheter thrombolysis with local anticoagulation and endovascular mechanical thrombectomy. Of the 25 patients selected for study inclusion, 12 had undergone emergency surgical exploration (group 1) and 13 had undergone the initial catheter-directed thrombolysis (group 2). Data extracted from each patient's records for statistical analyses included method of diagnosis, symptoms, etiology and risk factors, thrombus location, initial management, morbidity, mortality, duration and total cost of hospitalization (in Renminbi, RMB), secondary operation, total length of bowel resection, duration of and findings in follow-up, and death/survival. RESULTS: The two treatment groups showed similar rates of morbidity, 30-d mortality, and 1-year survival, as well as similar demographic characteristics, etiology or risk factors, computed tomography characteristics, symptoms, findings of blood testing at admission, complications, secondary operations, and follow-up outcomes. In contrast, the patients who received the initial non-operative treatment of transcatheter thrombolysis had significantly shorter durations of admission to symptom elimination (group 1: 18.25 ± 7.69 d vs group 2: 7.23 ± 2.42 d) and hospital stay (43.00 ± 13.77 d vs 20.46 ± 6.59 d), and early enteral or oral nutrition restoration (20.50 ± 5.13 d vs 8.92 ± 1.89 d), as well as significantly less total length of bowel resection (170.83 ± 61.27 cm vs 29.23 ± 50.24 cm) and lower total cost (200020.4 ± 91505.62 RMB vs 72785.6 ± 21828.16 RMB) (P < 0.05 for all). Statistical analyses suggested that initial transcatheter thrombolysis is correlated with quicker resolution of the thrombus, earlier improvement of symptoms, stimulation of collateral vessel development, reversal of intestinal ischemia, receipt of localizing bowel resection to prevent short bowel syndrome, shorter hospitalization, and lower overall cost of treatment. CONCLUSION: For ASMVT patients with circumscribed peritonitis, early diagnosis is key to survival, and non-operative transcatheter thrombolysis is feasible and effective as an initial treatment.

Assessment of the interface between retroperitoneal fat infiltration of pancreatic ductal carcinoma and the major artery by multidetector-row computed tomography: surgical outcomes and correlation with histopathological extension.

BACKGROUND: Precise assessment of retroperitoneal invasion is clinically important to allow the achievement of negative margin resections. METHODS: The clinical records of 132 patients who underwent macroscopic curative pancreaticoduodenectomy for invasive ductal carcinoma of the pancreas between 2004 and 2008 were retrospectively examined. The clinicopathological factors, including retroperitoneal fat infiltration classified into four groups by multidetector-row computed tomography (MDCT), were analyzed. The relationship between the grade of retroperitoneal fat infiltration and surgical outcomes, as well as various histopathological factors, was also investigated. RESULTS: The 5 year survival rate was 55.6 % for grade 0 infiltration (n = 8), 38.7 % for grade 1 (n = 54), 16.4 % for grade 2 (n = 49), and 0 % for grade 3 (n = 21). There were significant differences in survival in each group. Extrapancreatic nerve invasion and the surgical margin status were significantly associated with retroperitoneal fat infiltration demonstrated on MDCT. According to the grading classification among the 43 patients with pathological portal vein invasion, the 5 year survival rate was 45.9 % for patients with grade 1, which was significantly better survival that those with grade 2 (P = 0.007). CONCLUSION: The grading criteria for retroperitoneal fat infiltration may be useful as a predictor of survival after pancreaticoduodenectomy for pancreatic head carcinoma. Pancreaticoduodenectomy with portal vein resection could provide favorable survival in patients with grade 1 retroperitoneal fat infiltration, even if histopathological portal vein invasion is present.

Assessment of vascular invasion in pancreatic head cancer with multislice spiral CT: value of multiplanar reconstructions.

The use of multiplanar reconstructions (MPRs) generated from multislice spiral CT (MSCT) data sets in the preoperative assessment of vascular invasion in pancreatic cancer was evaluated. Forty patients underwent biphasic high-resolution MSCT prior to surgery for pancreatic head cancer. Image reconstruction included thin-slice axial, sagittal and coronal MPRs as well as an MPR perpendicular to the course of a major peripancreatic vessel in proximity to the tumor. CT criteria for vascular invasion were: (1) circumferential involvement >180 degrees and (2) vessel narrowing. Imaging findings of 52 vessels were correlated with surgical and histopathological reports. Regarding the CT criterion circumferential involvement, vascular invasion was demonstrated on axial MPRs with a sensitivity and specificity of 58 and 97%. For the assessment with coronal and sagittal MPRs sensitivity was only 47%. Vascular invasion was recognized best on perpendicular MPRs with a sensitivity, specificity and accuracy of 74, 97 and 88%, respectively. Vessel narrowing was a less reliable CT criterion for vascular invasion, mainly due to the lower specificity of 91% obtained with each available MPR. Thin-slice MPRs oriented perpendicularly to a possibly invaded vessel exactly depict the grade of circumferential involvement and thus have the capability to improve the assessment of vascular invasion in pancreatic cancer.

Dual-phase helical CT of pancreatic adenocarcinoma: assessment of resectability before surgery.

OBJECTIVE: The aim of our study was to prospectively evaluate the accuracy of dual-phase helical CT in the preoperative assessment of resectability in patients with suspected pancreatic cancer using surgical and histopathologic correlation. SUBJECTS AND METHODS: Between January 1999 and December 2000, 76 patients with suspected pancreatic cancer underwent preoperative evaluation and staging with dual-phase helical CT (3-mm collimation for pancreatic phase, 5-mm collimation for portal phase). Iodinated contrast material was injected IV (170 mL at a rate of 4 mL/sec); acquisition began at 40 sec during the pancreatic phase and at 70 sec during the portal phase. Three radiologists prospectively evaluated the imaging findings to determine the presence of pancreatic tumor and signs of unresectability (liver metastasis, vascular encasement, or regional lymph nodes metastasis). The degree of tumor-vessel contiguity was recorded for each patient (no contiguity with tumor, contiguity of < 50%, or contiguity of > or =50%). RESULTS: Thirty-nine patients with pancreatic adenocarcinoma were surgically explored. Curative resections were attempted in 34 patients and were successful in 25. The positive predictive value for resectability was 73.5%. Nine patients considered resectable on the basis of CT findings were found to be unresectable at surgery because of liver metastasis (n = 5), vascular encasement (n = 2), or lymph node metastasis (n = 2). We found that the overall accuracy of helical CT as a tool for determining whether a pancreatic adenocarcinoma was resectable was 77% (30/39 patients). CONCLUSION: Dual-phase helical CT is a useful technique for preoperative staging of pancreatic cancer. The main limitation of CT is that it may not reveal small hepatic metastases.

Size reduction of small bowels from adult cadaveric donors to alleviate the scarcity of pediatric size-matched organs: an anatomical and feasibility study.

BACKGROUND: Small bowel transplantation in children weighing less than 10 kg is hindered by the lack of size-matched donors. The ability to create reduced size small bowel grafts from adult cadaveric donors suitable for use in young children has been studied. METHODS: Volumetric assessment of computed tomography scans were used to evaluate abdominal cavity and small bowel volumes in children. Small bowels were retrieved from adult cadaveric donors and reduced in size. RESULTS: Computed tomography studies of the abdominal cavity showed that the mean volume available for a small bowel graft was 260 ml in children less than 5 kg (n = 5) and 460 ml in children weighing 5-10 kg (n = 5). Fifteen small bowels were successfully reduced to provide an ileal graft of one meter while keeping the whole length of the superior mesenteric artery and vein after their dissection in the proximal part of the mesentery. The mean volume of the grafts created was 270 ml in seven thin patients (body mass index [BMI] <25), 390 ml in five preobese patients (25< BMI<30), and 490 ml in three obese patients (BMI>30). Mesenteric transillumination in thin donors allowed safe dissection and complete hemostasis. No diameter reduction was required. Technical modifications permitted the creation of two grafts, one ileal and the other jejunal from a single donor. Volumetric and surgical data show that implantation of up to two meters of ileum from a thin adult weighing up to 80 kg is feasible in children weighing less than 10 kg. CONCLUSION: Size reduction of adult cadaveric small bowels can provide suitable grafts for children of less than 10 kg and could expand the potential pool of donors for these patients.

Ultrasonographic assessment of intragastric volume in neonates: factors affecting the relationship between intragastric volume and antral cross-sectional area.

Measuring antral cross-sectional area by ultrasonography can be an ideal way to evaluate intragastric milk volume in infants. Technical details, however, remain to be established before its clinical application. We investigated the effects of posture and ultrasonographic plane on the correlation between milk volume and antral cross-sectional area. After gastric aspiration through a nasogastric tube, healthy newborns were fed 0, 10, 20, and 40 ml of milk cumulatively, and antral cross-sectional area was measured in either upright, sitting, or right lateral position. To determine the best sonographic plane, subjects were put in the right lateral position and antral cross-sectional area was measured in the plane of the aorta and either the superior mesenteric artery, the superior mesenteric vein, the midline of the abdominal surface, 1 cm right of midline, or 2 cm right of midline. The results showed that antral cross-sectional area reflects intragastric milk volume most accurately, with minimal gas interference when measured in the right lateral position. The area correlates well with milk volume in the plane of the aorta and either the superior mesenteric artery, the superior mesenteric vein, or the midline. Next, we studied the effect of intragastric gas on the antral cross-sectional area in subjects who were given 40 ml of milk followed by an injection of air. More than 20 ml of intragastric gas increases antral cross-sectional area significantly. Ultrasonographic evaluation of intragastric volume requires attention to the above factors.

CT arterial portography vs pancreatic arteriography in the assessment of vascular involvement in pancreatic and periampullary tumors.

OBJECTIVE: Preoperative staging of pancreatic tumors is frequently accomplished through a combined effort of CT and arteriography. For tumor detection and delineation of disease extent CT is utilized routinely, with CT arterial portography (CTAP) being the single most accurate study for the detection liver metastases. Arteriography has remained the "gold" standard for assessing vascular involvement. The purpose of this study was to determine whether CTAP could become the single study of choice for assessing resectability in patients with pancreatic and periampullary tumors with particular emphasis on its accuracy in determining vascular involvement. MATERIALS AND METHODS: Radiologic studies and medical records were reviewed in 20 patients who had received both CTAP and arteriographic examinations for preoperative assessment of pancreatic and periampullary tumors. These findings were correlated with results from either surgery (12 cases) or percutaneous biopsy and follow-up (8 cases) in 12 nonresectable and 8 resectable tumors. RESULTS: Arteriography and CTAP correctly concurred in 75% of cases (15 of 20); CTAP correctly demonstrated vascular involvement not appreciated on arteriography in 15% (3 of 20) with an overall sensitivity and specificity of 90 and 100%, respectively. Arteriography was superior to CTAP in one patient (5%) with an overall sensitivity and specificity of 70 and 90%, respectively, for predicting vascular involvement by tumor. CONCLUSION: Our experience suggests that CTAP is more accurate than arteriography for demonstrating tumor involvement of major peripancreatic vessels. Because CTAP, additionally, has a high sensitivity for detecting liver metastases, no further studies may be necessary to determine operability of these patients.

Assessment of the human splanchnic venous volume-pressure relation using radionuclide plethysmography. Effect of nitroglycerin.

BACKGROUND: No method exists to assess human splanchnic venous function, the most important region in terms of vascular capacity. METHODS AND RESULTS: We studied 25 stable patients without heart failure or hypertension to develop a method to assess the splanchnic venous volume-pressure (V-P) relation and to determine the effect of nitroglycerin (GTN). We used blood pool scintigraphy to assess changes in regional splanchnic vascular volume (SVV) and low levels of continuous positive airway pressure (CPAP) to passively alter venous pressure and thus, SVV. We postulated that the relation between SVV and the CPAP used would reflect the capacitance of the splanchnic venous bed and that changes in the position of this relation would provide a relative measurement of any change in capacitance. In 12 patients (group 1), the splanchnic vascular V-P curves were recorded before and 2, 9, and 20 minutes after 0.6 mg sublingual GTN; in eight patients (group 2), recordings were made at similar times before and after sublingual administration of placebo; in five patients (group 3), the hemodynamic effects of CPAP were assessed by means of right and left cardiac catheterization. Right atrial and femoral venous pressures increased (p < 0.001) and cardiac output fell (p < 0.05) during CPAP. There was an apparently linear relation between CPAP and SVV (r = 0.74-0.98); SVV increased an average of 7.4 +/- 2.2% (p < 0.001) by 12 cm H2O CPAP: The splanchnic vascular V-P curves were reproducible with minimal variability in SVV (+/- 2%, p > 0.2) in group 2. After administration of GTN, the splanchnic vascular V-P curve shifted away from the pressure axis in a parallel fashion by an average of 9.4 +/- 5.4% (p < 0.001). CONCLUSIONS: We have developed a reproducible noninvasive technique that may be used to assess human splanchnic venous V-P relations. We have demonstrated for the first time in humans that GTN exerts its dilatory effect by increasing the unstressed splanchnic venous volume.

Assessment of portosystemic shunting from superior mesenteric vein by duodenal administration of iodoamphetamine I123.

Portosystemic shunting (PSS) from the superior mesenteric vein (SMV) was evaluated with the duodenal administration of iodoamphetamine I123 (IMP) in patients with chronic hepatitis and liver cirrhosis. After duodenal intubation, IMP was administered through a tube, and then scintigraphy including the pulmonary and hepatic regions was performed. In all patients, images of the liver and/or lungs were observed within 10 min and became clear with time, due to a good absorption of IMP from the intestine. On the other hand, IMP appears not to be absorbed from the stomach. The portosystemic shunt index was calculated by dividing counts of lungs by counts of liver and lungs. The shunt index (mean +/- SE) was 1.5% +/- 0.8%, 12.6% +/- 3.7% and 28.3% +/- 4.5% in chronic hepatitis, compensated cirrhosis and decompensated cirrhosis, respectively. This index was significantly higher in cirrhosis, especially in decompensated cirrhosis. Therefore, transintestinal portal scintigraphy with IMP could be a useful method for the non-invasive and quantitative evaluation of PSS from the SMV in portal hypertension.

Noninvasive assessment of portosystemic shunting in extrahepatic portal hypertension in rats.

A simple reproducible animal model of extrahepatic portal hypertension (EHPHT) has been developed in weanling Wistar rats using a two-stage ligation of the portal vein. This model consistently produces substantial collaterals, both portosystemic (hepatofugal) and portoportal (hepatopetal). Using dynamic hepatic scintigraphy (DHS) with 99mTechnetium sulphurcolloid, hepatopetal collateral flow was measured as the mesenteric fraction (MF) of total hepatic blood flow and compared with measurement of hepatofugal collateral flow (portosystemic shunting) following intraportal injection of radiolabeled microspheres. Strong and significant correlation between the two assessments was found with reduction in MF denoting increased portosystemic shunting (PSS). The technique of DHS has been used successfully in adults to assess compromised portal venous flow and is a simple noninvasive test to aid diagnosis, assessment, and follow-up of children with EHPHT.