Normal pancreatic volume assessment using abdominal computed tomography volumetry.

ABSTRACT: To determine the normal range of pancreatic volume (PV) in Chinese adults using computed tomography (CT) volumetry. To assess the relationships of PV with patient demographics and clinical parameters. To analyze the degree of correlation between PV values determined by manual segmentation and those calculated by formulas.A total of 240 adults (120 women, 120 men) between the ages of 18 and 79 years were reviewed. There were 6 groups of patients, with 40 patients in each decade regarding age. PV was segmented manually on computed tomography images slice by slice for each patient, and 2 formulas were used to calculate PV∗ and PV#.The mean PV was 77.44 ±â€Š19.11 cm3 (range from 28.55-138.15 cm3). PV was significantly correlated with height (r = 0.427, P < .001), weight (r = 0.525, P < .001), body mass index (r = 0.377, P < .001), the width of the first lumbar vertebral body (r = 0.166, P = .01), the transverse abdominal diameter (r = 0.455, P < .001), and the sagittal abdominal diameter (r = 0.456, P < .001). There was a negative correlation between PV and age (r = -0.209, P = .001). The correlation coefficients between PV and PV∗ and PV# were 0.676 and 0.376, respectively, with both P < .001.PV associated with patient demographics and clinical parameters. A more accurate and simpler formula should be used in the future to calculate and monitor changes in PV.

What is the nature of pancreatic consistency? Assessment of the elastic modulus of the pancreas and comparison with tactile sensation, histology, and occurrence of postoperative pancreatic fistula after pancreaticoduodenectomy.

BACKGROUND: Although pancreatic consistency is a factor known to have an impact on the occurrence of postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD), it usually is assessed subjectively by the surgeon. Measurement of the elastic modulus (EM), a parameter characterizing the elasticity of a material, may be one approach for achieving objective and quantitative assessment of pancreatic consistency. This study was conducted to investigate the utility of determining the EM of the pancreas. METHODS: Fifty-nine patients who underwent PD and measurement of the EM of the ex vivo pancreas were investigated. Data for EM were compared with the tactile evaluation made by surgeons, histologic findings, and the occurrence of POPF. RESULTS: The EM of the pancreas was correlated with the tactile evaluation made by the surgeon (soft pancreas, 1.4 ± 2.1 kPa vs hard pancreas, 4.4 ± 5.1 kPa; P < .001). An EM of >3.0 kPa was correlated with histologic findings including increased ratios of azan-Mallory positivity (P = .003) and α-smooth muscle actin positivity (P = .006), a decreased lobular ratio (P = .021), and an increased vessel density (P < .001). Patients with a pancreatic EM of <3.0 kPa had an increased risk of POPF (hazard ratio, 9.333; P = .002). CONCLUSION: Assessment of the EM of the resected pancreas reflects the tactile evaluation made by the surgeon and histological degree of pancreatic fibrosis, and is correlated with the occurrence of POPF after PD.

Total pancreatectomy: porcine model for inducing diabetes - anatomical assessment and surgical aspects.

BACKGROUND: The swine is an essential model for carrying out preclinical research and for teaching complex surgical procedures. There is a lack of experimental models describing anatomical and surgical aspects of total pancreatectomy in the pig. MATERIALS AND METHODS: The experiments were performed on 10 white male swine weighing 27-33 kg. The animals were premedicated with midazolam (0.4 mg/kg, i.m.) and ketamine (4 mg/kg, i.m.). Anesthesia was induced with propofol (1-2 mg/kg, i.v.) and was maintained with propofol and fentanyl (0.3 mg and 0.1 µg/kg/min, respectively, i.v.). The surgical period ranged from 44 to 77 min. The pancreas anatomy, and the main arterial, venous and pancreatic duct anatomy were assessed. RESULTS: The pancreas anatomy was composed of 3 lobes, the 'splenic', 'duodenal' and 'connecting' lobe which is attached to the anterior portion of the portal vein. The splenic artery and the junction of the splenic vein and portal vein were divided. The left gastric artery was dissected and separated from its origin at the splenic artery. The head of the pancreas is disposed in a C shape. The pancreas was dissected and liberated from the right portion of the portal vein and the infrahepatic vena cava. The pancreas was separated from the duodenum preserving the pancreaticoduodenal artery, then we performed the total pancreatectomy preserving the duodenum, common bile duct and spleen. CONCLUSION: Total pancreatectomy with duodenum, bile duct and spleen preservation in the pig is feasible and an important instrument for research purposes and teaching surgical technique.

Rapid quantitative assessment of the pig pancreas biopsy predicts islet yield.

BACKGROUND: The cost of islet procurement from donor pigs is increased by the use of organs that produce low yields. We developed an assessment system using dithizone-stained pig pancreas biopsies to enable the preselection of donor organs. METHODS: Pig pancreas biopsy slices were soaked in dithizone solution. The islets were evaluated before islet isolation by converting the islet counts (IC) to islet equivalents (IE), and then determining the IE/cm(2), IE/IC, % islets >150 microm, and % islets >200 microm. These parameters were evaluated in 3 different areas of the pancreas (duodenal, splenic, and connecting lobe; n = 42 each). Stepwise multivariate linear regression analysis was performed to assess for correlations with islet yield and decide which area of the pancreas had the most predictive value. To identify other predictors, including donor and islet isolation variables, we performed binary logistic regression analysis with significant variables from the univariate analysis (n = 67). For this analysis, the pigs were categorized into high (n = 23) and low (n = 44) yield groups. RESULTS: Stepwise multivariate linear regression analysis revealed that IE/cm(2) of the splenic lobe significantly predicted islet yield. Binary logistic regression analysis indicated that the IE/mm(2) of the splenic lobe was the only parameter that significantly correlated with successful pig islet isolations (P = .01; odds ratio 3.605). Variables associated with donor and islet isolation, such as age, gender, ischemic time, or enzyme lot, were not significantly correlated with islet yield. CONCLUSION: Our study suggests that the islet distribution of splenic lobe biopsies can be a reliable predictor of islet yield from pig pancreata.

Assessment of human islet isolation with four different collagenases.

BACKGROUND: The isolation of islets from the human pancreas critically depends on the efficiency of the digestive enzymes. Liberase HI had been used as a standard preparation until the issues concerning bovine spongiform encephalopathy. Thus, we must now use other collagenases for clinical islet transplantation, four of which we have evaluated herein. METHODS: The digestion of each of 17 pancreata from brain-dead donors was performed using the following collagenases: Liberase HI (HI; Roche, n = 9); Liberase MTF C/T (MTF; Roche, n = 4); Collagenase NB1 Premium Grade (NB1; Serva, n = 7); or Clzyme Collagenase HA (CI, VitaCyte, n = 4). Islet isolations were based on the Edmonton protocol for HI, whereas our modified islet isolation method was used for the three new enzymes (MTF, NB1, and CI). RESULTS: There were no significant differences in donor age, body mass index, pancreas size, and cold ischemic time among the four groups. The phase I time in the NB1 group was significantly shorter than in the CI group (P = .0014). The prepurification IEQ/g in the HI group was significantly lower than the others (P = .0003 vs MTF, .0007 vs NB1, and .0009 vs CI, respectively). The postpurification IEQ/g in the MTF group was significantly higher than in the HI group (P = .006). The viability in the NB1 group was significantly greater than the HI group (P = .003). CONCLUSION: Three new enzymes (MTF, NB1, and CI) may enable us to obtain higher islet yields than with HI.

Real-time noninvasive assessment of pancreatic ATP levels during cold preservation.

31P-NMR spectroscopy was utilized to investigate rat and porcine pancreatic ATP:P(i) ratios to assess the efficacy of existing protocols for cold preservation (CP) in maintaining organ quality. Following sacrifice, rat pancreata were immediately excised or left enclosed in the body for 15 minutes of warm ischemia (WI). After excision, rat pancreata were stored at 6 degrees C to 8 degrees C using histidine-tryptophan-ketoglutarate solution (HTK) presaturated with air (S1), HTK presaturated with O2 (S2), or the HTK/perfluorodecalin two-layer method (TLM) with both liquids presaturated with O2 (S3). 31P-NMR spectra were sequentially collected at 3, 6, 9, 12, and 24 hours of CP from pancreata stored with each of the three protocols examined. The ATP:Pi ratio for rat pancreata exposed to 15 minutes of WI and stored with S3 increased during the first 9 hours of CP, approaching values observed for organs procured with no WI. A marked reduction in the ATP:Pi ratio was observed beyond 12 hours of CP with S3. After 6 hours of CP, the ATP:Pi ratio was highest for S3, substantially decreased for S2, and below detection for S1. In sharp contrast to the rat model, ATP was barely detectable in porcine pancreata exposed to minimal warm ischemia (<15 minutes) stored with the TLM regardless of CP time. We conclude that 31P-NMR spectroscopy is a powerful tool that can be used to (1) noninvasively evaluate pancreata prior to islet isolation, (2) assess the efficacy of different preservation protocols, (3) precisely define the timing of reversible versus irreversible damage, and (4) assess whether intervention will extend this timing.

Estimation of pancreas weight from donor variables.

Previous studies have identified several donor factors affecting the outcome of islet isolation. Pancreas weight has not been considered as a donor selection criterion, because a value cannot be obtained prior to organ procurement. However, a larger pancreas will likely contain a higher number of islets. Therefore, the prediction of pancreas weight would be helpful in donor selection, benefiting cost and efficiency of the islet isolation laboratory. The purpose of this study was to investigate normal pancreas weight in cadaveric donors and identify pancreas weight predictors from demographic data of cadaveric organ donors. We retrospectively analyzed data on pancreas weight from 354 cadaveric donors with respect to gender, age, body weight, body height, body mass index (BMI), and body surface area (BSA). In men, pancreas weight correlated more closely with body weight than with age, height, or BMI. BSA was as strong a correlate of pancreas weight as body weight. In women, pancreas weight had a similar pattern of relationships, with generally lower correlation coefficients. On the basis of the observation of gender-specific pancreas weight difference in elderly donors, stepwise multiple linear regression analyses were conducted separately for younger (< or =40 years) and elderly (> or =41 years) donors. In younger donors, body weight and age were the major predictors of pancreas weight [pancreas weight (g) = 4.355 + 0.742 x body weight (kg) + 0.837 x age (years) (R2 = 0.564, p < 0.001)]. In contrast, pancreas weight of elderly donors was best predicted by BSA and gender [pancreas weight (g) = -17.624 + 60.036 x BSA (m2) - 7.152 x gender (R2 = 0.372, p < 0.001; "gender": 1 = female, 0 = male)]. Pancreas weight was found to be positively associated with pre- and postpurification islet yields. These formulae should contribute to the estimation of pancreas weight, and thus improve donor selection for islet isolation and transplantation.

Normal organ volume assessment from abdominal CT.

We determined the normal distribution of abdominal organ volumes measured from abdominal computed tomographic (CT) images. A total of 149 adult abdominal CT studies were selected, and 711 organs (388 from males, 323 from females) were outlined by hand on each CT image by using a computer. More than 18000 organ outlines were traced. The organs studied included left and right kidneys, left and right adrenals, spleen, pancreas, and liver, and the first lumbar vertebrae was also evaluated. Using the known pixel size and section thickness, organ volumes were computed. Organ volumes were corrected for height and weight for each sex. The normal and cumulative normal distributions for each organ studied were computed, demonstrating the range of organ volumes for each sex that exist in the normal adult population. Organ volumes ranged from a mean of 4.4 mL (female left adrenal) to 1710 mL (male liver). Mean organ volumes were 64.4, 156.5, 179.8, and 1411 mL for the female pancreas, kidneys, spleen, and liver, respectively. Corresponding male volumes were 87.4, 193.1, 238.4, and 1710 mL, respectively. Tabular data are provided that indicate the relative size for each organ volume in terms of the cumulative probability distribution. Normative data are provided to allow physicians to estimate where in the normal range a particular organ volume lays. Organ volumes may be useful as quantitative indices of pathologic conditions.

Functional assessment of pancreatic parenchyma after secretin administration using serial T2-weighted echo-planar magnetic resonance imaging.

Signal intensity (SI) changes of pancreatic parenchyma were evaluated after intravenous administration of secretin using T2-weighted single-shot spin-echo echo-planar imaging (EPI) to assess this method as a magnetic resonance (MR) test of pancreatic exocrine function. Nine volunteers were studied with serial single-shot EPI of the pancreas for 15 minutes after the injection of secretin or saline. The normal pattern of pancreatic SI change was demonstrated after intravenous injection of secretin, a single peak at 3-4 minutes in the head, body, and tail, followed by a gradual decrease in SI. Saline injection did not induce a significant SI change. There was no statistical difference in the peak contrast ratios (first mean, 1.21-1.25, vs. second mean, 1.18-1.22) and peak times (first mean, 3.2-3.7 minutes, vs. second mean, 3.1-3.6) in a repeat study. By evaluating the pattern of time-response curves obtained from serial T2-weighted EPI after secretin injection, pancreatic exocrine function may be directly assessed at the level of the head, body, and tail.

The significance of aductal zones on pancreatograms: an anatomo-clinical assessment.

The authors analyzed 177 endoscopic retrograde pancreatograms (ERPs) with normal findings. The complete visualization of the side branches was achieved in 128 patients (72.3%), and aductal zones in the isthmus and mid-body of the pancreas were noted in 49 (27.3%) of these patients. The existence and incidence of the aductal zones were evaluated and verified in 141 anatomical duodenopancreas specimens. Thirty-two corrosion casts and 109 postmortem pancreatograms were analyzed. The postmortem specimens had a 36.2% incidence of aductal zones in the same location, with no statistically significant difference compared with the clinical pancreatograms. The visualization of the side branches was 100% on the postmortem pancreatograms, indicating that the clinical ERCP incidence of aductal zones is realistic.

Economic viability of crosses of Bos taurus and Bos indicus for dairying in warm climates.

Countries in the warm climatic zones need greater domestic supplies of milk. To increase yields, the option that is least expensive and most widely used is to cross dairy breed sires with local cattle. First generation crosses have more vigor than other crosses under stressful environmental conditions; growth rate, milk yield, and reproduction rate exceed those of local breeds and other crossbred combinations. On average, lactating first generation crosses are fed energy at 45 to 60% below their potential response, which limits their capabilities. Other crosses with local breeds fall short of first generation crosses as do some of the present synthetic breeds with 5/8 to 3/4 dairy breeding. Well-fed (> 2.5 maintenance needs) Holstein or Jersey crosses containing 1/4, 1/2, or 3/4 Bos indicus (Zebu) tend to follow projections of parental means for milk yield, reproduction rate, and tolerance to heat stress; however, for crosses, losses exceed predictions for lactation length, persistency of milk yield, feed efficiency, and rate of milking. Size of thoracic and abdominal organs, size of endocrine glands, stomach weight, and intestine length are lower than expected compared with values for purebreds. The smaller digestive system affects feeding intake of B. indicus crosses, and the smaller endocrine glands appear to limit responses to high energy diets. Possible directional dominance of B. indicus needs further investigation. The first generation crosses could support their use for dairy purposes if feeding rate and management were optimal, but prospects for other crosses remain questionable.

Fetal pig pancreas--a preliminary assessment of tissue for transplantation.

Porcine fetal pancreases (PFP) obtained from 4 pregnant sows were pooled, minced into 1 mm3 fragments and studied in organ culture for up to 30 days to determine tissue viability and insulin production in vitro. After 7-9 days in culture, some of these explants were transplanted into euglycemic, N:NIH-nu(s) nude recipient mice, and studied histologically over 69 days following grafting. Using RPMI 1640 supplemented with 5% fetal calf serum as the culture medium in 90% air/10% CO2, it was found that explants were viable with insulin production detected in vitro, which was maximal at day 7 (197 +/- 18.9 mU/L, n = 11), and gradually declined thereafter. By 22 days, insulin levels were less than 60.1 +/- 28.5 mU/L (n = 6). Histology of the explants showed viable tissue with evidence of mitoses present in insulin-positive cells at day 16 in vitro. Beyond this time, tissue viability diminished. Explants transplanted into euglycemic nude mice did not undergo rejection during the observation period of 69 days. Grafts remained viable with evidence of an increase in mitotic activity in the endocrine tissue on immunoperoxidase staining. These preliminary investigations confirm that pancreatic explants from porcine fetuses can be maintained in culture for up to 16 days. Such explants, when transplanted under the kidney capsule of euglycemic, nude mice, did not undergo necrosis, but remained viable, with evidence of mitoses in the islet tissue.

[The internal echo pattern of the normal pancreas. An assessment of the aging process and body weight dependence by sonographic gray-scale analysis]. / Das Binnenreflexmuster des normalen Pankreas. Erfassung der Altersentwicklung und der Gewichstabhängigkeit durch sonographische Grauwertanalyse.

Sonography of the pancreas was evaluated quantitatively in 94 normal subjects. The grey-scale values in the head and body of the pancreas were measured and compared with those of retroperitoneal fat. The echogenicity of the pancreas and the contrast between pancreas and fat were correlated with the age and weight of the subjects. Semi-quantitative studies revealed a positive correlation between echogenicity and age (r = 0.505); this can be confirmed to a high degree of statistical significance by quantitative analysis of pancreatic grey-scale values (r = 0.55 for the head and 0.71 for the body). Further improved correlation with age is obtained by computing the sonographic contrast between the pancreas and the retroperitoneal fat (r = 0.66 for the head and 0.77 for the body of the pancreas). It is concluded that determination of the grey-scale value can provide additional information particularly if one uses retroperitoneal fat as a reference tissue.

Magnetic resonance imaging of the pancreas.

In this article, the author discusses his experience using a superconducting magnet for evaluation of the pancreas. The discussion includes evaluation of neoplastic and inflammatory disease of the pancreas and comparison of MRI with CT scanning.