Portal and Hepatic Venous Territorial Mapping in Healthy Human Livers: Virtual Three-Dimensional Computed Tomography Size-Shape-Topography Study.

OBJECTIVES: This study aimed to assess portal and hepatic venous volumes as related to the planning of complex liver resections and segmental liver transplant. MATERIALS AND METHODS: We analyzed 3-dimensional computed tomography of portal and hepatic vein territorial maps of 140 potential living related liver donors. Portal and hepatic vein maps were simulated both separately and in overlap (cross-mapping) to calculate inflow and outflow volumes. RESULTS: In total liver volume, the right hemiliver was always dominant (mean 64.7 ± 4.8%) and the right medial sector (mean 36.4 ± 6.8%) and segment 8 (mean 19.1 ± 4.3%) accounted for the largest volumes, whereas the left medial sector(mean 13.5 ± 3.1%) and segment 4A (mean 5.8 ± 1.8%) accounted for the smallest volumes (with exclusion of caudate lobe). The right hepatic vein was dominant for both right hemiliver and right lateral sector and had the largest drainage volume in total liver volume (mean 40.0 ± 11.2%). The left hepatic vein was dominant for both left hemiliver and left lateral sector but had the smallest drainage volume fortotal liver volume (mean 21.3 ± 5.0%). The middle hepatic vein drained 50.2 ± 12.5% of the right medial sector and 75.8 ± 15.4% of the left medial sector. In 67 cases, an accessory vein (inferior hepatic vein) drained 16.5 ± 13.2% ofthe right hemiliver, 31.4 ± 25.1% ofthe right lateral sector, 26.6 ± 23.2% of segment 7, and 37.4 ± 31.3% of segment 6. CONCLUSIONS: The portal and hepatic vein territorial anatomy was characterized by extensive individual variability. An extremely smallremnant volume (<25% of total liver volume) precluded a minority of virtual extended left and a majority of extended right hepatectomies. Left trisectionectomy was associated with risky drainage from the middle hepatic vein, extensive segment 6 remnant congestion volume in 8% of cases, and right lateral sector-favorable inferior hepatic vein large drainage pattern in 13% of livers.

Long-term follow-up after right hepatectomy for adult living donation and attitudes toward the procedure.

OBJECTIVES: To determine the long-term health status of donors after right hepatectomy for adult live donor liver transplantation (ALDLT). BACKGROUND: The long-term outcomes for ALDLT donors are unknown. METHODS: ALDLT donors undergoing right hepatectomy from April 1998 to June 2007 were invited to complete a questionnaire regarding health status, satisfaction (1-10/worst-best scale), self-esteem, willingness to donate again, and suggestions for improvement. In addition, donor files and cholecystectomy specimens were reviewed. Fisher's exact test, Kaplan-Meier and logistic regression analyses were performed. RESULTS: Eighty-three donors were contacted (median age: 36 years; median follow-up: 69 months). 39 (47%) were free of symptoms. The remaining 44 (53%) reported: intolerance to fatty meals and diarrhea (31%), gastroesophageal reflux associated with left liver hypertrophy (9%), incisional discomfort requiring pain medications (6%), severe depression requiring hospitalization (4%), rib pain affecting lifestyle (2%), and exacerbation of psoriasis (1%). Median satisfaction score was 8. Self-esteem diminished in 5%. Thirty-nine (47%) recommended improvements particularly more detailed informed donor consent and a centralized living donor liver registry. Seventy-eight (94%) were willing to donate again. There were no differences between donors with and without complaints with respect to: donor age, gender, early complications and follow-up time, young-to-old donation, recipient diagnosis of malignancy and death of the recipient. Noninflamed donor cholecystectomy specimens correlated with intolerance to fatty meals and diarrhea (P = 0.001). CONCLUSIONS: ALDLT donors are at risk for long-term complaints that are neither reflected nor related to early complications. This information should be included in both the donor evaluation and the ALDLT decision-making process.

"Anatomical" versus "territorial" belonging of the middle hepatic vein: virtual imaging and clinical repercussions.

BACKGROUND: Venous drainage patterns are of vital importance in live donor liver transplantation. The purpose of this study was to delineate "anatomical-topographical" and "territorial-physiologic" patterns of the middle hepatic vein (MHV) in a 3-D liver model as determined by the Pringle line and its drainage volume of the right and left hemilivers. METHODS: One hundred thirty-seven consecutive live donor candidates were evaluated by 3-D CT reconstructions and virtual hepatectomies. Based on right (R) and left (L), anatomical (A) and territorial (T) belonging patterns of the MHV, each individual was assigned to one of four possible types: type I:A(R)-T(R); type II:A(L)-T(L); type III:A(R)-T(L); type IV:A(L)-T(R). Couinaud's anatomical MHV variants A-C were subsequently included in our combined anatomical/territorial MHV belonging classification. RESULTS: The MHV showed a significant predominance of right "anatomical" (59.1%) and left "territorial" belonging patterns (65.7%). The paradoxical combinations A(R)-T(L) (type III) and A(L)-T(R) (type IV) were encountered in 36.5% and 11.7% of cases, respectively. The constellations Couinaud's A-belonging type IV and Couinaud's C-belonging type IV were predictive of right hemiliver venous congestion. CONCLUSIONS: (1) Almost half of all livers in our series had paradoxical "anatomical"/"territorial" MHV belonging patterns that placed them at risk for right and left hepatectomies. (2) The proposed combined "anatomical"/"territorial" MHV belonging types (I-IV) provide useful preoperative information. (3) Combined types III and IV as well as Couinaud's A-IV, and Couinaud's C-IV should be considered particularly risky for venous congestion in right hemiliver grafts and in extended left hepatectomies.

Changes in staging for hepatocellular carcinoma after radiofrequency ablation prior to liver transplantation as found in the explanted liver.

BACKGROUND/AIMS: To analyze the efficacy of radiofrequency ablation (RFA) prior to liver transplantation (LT) in liver explants. METHODOLOGY: We reviewed pathological findings in the explanted livers of 13 patients with histologically proven HCC and liver cirrhosis who underwent RFA as bridging treatment prior to LT. Eight patients had solitary nodules with a median diameter of 4cm, whereas five patients had two tumors each with a median total diameter of 3.3cm prior to RFA. One session of RFA was performed by all patients. RESULTS: Tumor regression was proved in 3/13 patients whereas steady disease was observed in 5/13 patients (38%). Tumor regression was observed only in one of the five patients having two tumors prior to RFA. Pathology proved a multifocal tumor in four patients, including one patient with a radiological presumed solitary tumor. Tumor progression was observed in 5/13 patients (38%). CONCLUSIONS: Although the majority of our patients (8/13, 62%) had a solitary tumor at the beginning of treatment, tumor progression was observed in a large proportion (38%) among them. The underestimation of tumor lesions in radiology and partial necrosis of the tumor achieved in most patients limit the role of RFA as bridging treatment prior to LT.

Drainage patterns of right and accessory hepatic veins: anatomical-functional classification derived from 3-dimensional CT reconstructions.

BACKGROUND/AIMS: Inadequate knowledge of the right (RHV) and accessory (IHV) hepatic 'venous drainage' territories can lead to severe postoperative venous congestion after right graft live donor liver transplantation. The purpose of our study was to define the anatomical-functional RHV and IHV drainage territories. METHODOLOGY: One hundred and forty consecutive live liver donor candidates were evaluated by means of 3-D CT reconstructions and 3-D virtual hepatectomies. Three RHV/IHV drainage patterns were identified and 'risky' configurations for right graft resections were defined. RESULTS: Livers with 'small' IHV drainage volumes (90.1±63.2mL) had dominant type IRHV/ IHV or non-dominant type III-RHV/IHV total liver (TL) complexes. All other cases had 'large' IHV volumes (294.7±115.5mL, p<0.001) with dominant type II-RHV/IHV TL complexes. Loss of IHV drainage volume (such as with no IHV reconstruction) in these cases was associated with a 'dominance transition' from right (RHV) to middle (MHV) hepatic veins, placing the grafts at 'high risk' for venous congestion. CONCLUSIONS: Type II-RHV/IHV complexes with large IHV drainage volumes are at 'high risk' for venous congestion in live donor liver transplantation.

Computer-assisted surgery planning for complex liver resections: when is it helpful? A single-center experience over an 8-year period.

OBJECTIVE: The purpose of this study was (1) to compare 2-dimensional computed tomographic (2D-CT) and 3D-CT computer-assisted preoperative surgical planning, and (2) to define the indications for the latter method. BACKGROUND: The determination of functional residual liver volumes and the imaging of intrahepatic anatomy are critical when planning complex liver resections. PATIENTS AND METHODS: Prospective study of 202 consecutive patients who underwent high-risk procedures (extended right/left hepatectomies, central resections, polysegmentectomies, large atypical resections, repeated resections, and hepatectomies in the setting of abnormal liver parenchyma). Preoperative evaluation included 3D-CT computer-assisted surgical planning (3D-CASP) and conventional 2D-CT imaging. Endpoints of the study were (1) determination of resectability and (2) changes in operative strategy (resection modifications/extensions/intrahepatic vascular reconstructions). RESULTS: Thirty-four of 202 cases were considered nonresectable on the basis of both 2D and 3D imaging results. In 56 (33%) instances, 3D-CASP either changed the 2D strategy (expansion of resection, n = 40; intrahepatic vascular reconstructions, n = 13) or provided an entirely different approach (n = 3). Eleven (5.4%) cases were considered unresectable at laparotomy on the basis of poor liver quality (n = 8) or unfeasible vascular reconstructions resulting in remnants too small to sustain physiologic function (n = 3). Significant differences between resectional 2D and functional 3D remnant liver volumes were observed in extended left hepatectomies and left trisectionectomies. CONCLUSIONS: 3D-CASP was particularly helpful in patients with unconventional resection planes and in those with central left tumors. Its main advantages were the individualized inflow/outflow virtual analyses and the accurate determination of safely perfused/drained retained liver volumes.

Mild endotoxemia during mechanical ventilation produces spatially heterogeneous pulmonary neutrophilic inflammation in sheep.

BACKGROUND: There is limited information on the regional inflammatory effects of mechanical ventilation and endotoxemia on the production of acute lung injury. Measurement of F-fluorodeoxyglucose (F-FDG) uptake with positron emission tomography allows for the regional, in vivo and noninvasive, assessment of neutrophilic inflammation. The authors tested whether mild endotoxemia combined with large tidal volume mechanical ventilation bounded by pressures within clinically acceptable limits could yield measurable and anatomically localized neutrophilic inflammation. METHODS: Sheep were mechanically ventilated with plateau pressures = 30-32 cm H2O and positive end-expiratory pressure = 0 for 2 h. Six sheep received intravenous endotoxin (10 ng x kg x min), whereas six did not (controls), in sequentially performed studies. The authors imaged with positron emission tomography the intrapulmonary kinetics of infused N-nitrogen and F-FDG to compute regional perfusion and F-FDG uptake. Transmission scans were used to assess aeration. RESULTS: Mean gas fraction and perfusion distribution were similar between groups. In contrast, a significant increase in F-FDG uptake was observed in all lung regions of the endotoxin group. In this group, F-FDG uptake in the middle and dorsal regions was significantly larger than that in the ventral regions. Multivariate analysis showed that the F-FDG uptake was associated with regional aeration (P < 0.01) and perfusion (P < 0.01). CONCLUSIONS: Mild short-term endotoxemia in the presence of heterogeneous lung aeration and mechanical ventilation with pressures within clinically acceptable limits produces marked spatially heterogeneous increases in pulmonary neutrophilic inflammation. The dependence of inflammation on aeration and perfusion suggests a multifactorial basis for that finding. F-FDG uptake may be a sensitive marker of pulmonary neutrophilic inflammation in the studied conditions.

The prone position results in smaller ventilation defects during bronchoconstriction in asthma.

The effect of body posture on regional ventilation during bronchoconstriction is unknown. In five subjects with asthma, we measured spirometry, low-frequency (0.15-Hz) lung elastance, and resistance and regional ventilation by intravenous (13)NN-saline positron emission tomography before and after nebulized methacholine. The subjects were imaged prone on 1 day and supine on another, but on both days the methacholine was delivered while prone. From the residual (13)NN after washout, ventilation defective areas were defined, and their location, volume, ventilation, and fractional gas content relative to the rest of the lung were calculated. Independent of posture, all subjects developed ventilation defective areas. Although ventilation within these areas was similarly reduced in both postures, their volume was smaller in prone than supine (25 vs. 41%, P < 0.05). The geometric center of the ventilation defective areas was gravitationally dependent relative to that of the lung in both postures. Mean lung fractional gas content was greater in the prone position before methacholine and did not increase as much as in the supine position after methacholine. In the prone position at baseline, areas that became ventilation defects had lower gas content than the rest of the lung. In both positions at baseline, there was a gradient of gas content in the vertical direction. In asthma, the size and location of ventilation defects is affected by body position and likely affected by small differences in lung expansion during bronchoconstriction.

Vascular and biliary anatomy of the right hilar window: its impact on recipient morbidity and mortality for right graft live donor liver transplantation.

BACKGROUND: Intrahepatic anatomic variations have been associated with both morbidity and mortality associated with live donor liver transplantation. The aim of our study was to evaluate central hilar and peripheral segmental vascular/biliary anatomy in right graft living donor liver transplantation. METHODS: From January 2003 to August 2007, three-dimensional (3D) computed tomography (CT) reconstructions and virtual 3D hepatectomies were performed in 71 consecutive right graft live liver donors. A combined two-level classification system addressing the four possible combinations of normal (N) and abnormal (A) central hilar and peripheral features based on both the existing classification and our own classification for portal (portal vein, PV), arterial (hepatic artery, HA) and biliary (bile duct, BD) systems was defined as follows: type I, N/N; type II, N/A; type III, A/N; and type IV, A/A. RESULTS: A simultaneous normal central hilar and peripheral segmental (N/N) anatomy for each system (PV, HA, BD) was found in <50% of grafts. The highest incidence of complex vascular and biliary reconstructions was observed with grafts having abnormal central (type III) or combined abnormal central/peripheral (type IV) anatomy. Central hilar arterial and biliary anomalies were predictors of morbidity by both univariable and multivariable analyses. CONCLUSIONS: Our two-level classification and 3D imaging techniques allowed a cautious surgical approach in high-risk cases. Central hilar anatomic variants of the arterial and biliary systems were associated with increased morbidity. Further randomized trials will help determine the precise extent of our observations.

Relation between shunt, aeration, and perfusion in experimental acute lung injury.

RATIONALE: In a pulmonary process characterized by spatially heterogeneous loss of aeration, the impairment of gas exchange is expected to depend on the regional distribution of perfusion relative to that of aeration. OBJECTIVES: To investigate how regional aeration, shunt, and perfusion are interrelated at different levels of end-expiratory pressure and how their interplay relates to global shunt fraction in acute lung injury. METHODS: Regional shunt and perfusion were assessed by imaging with positron emission tomography the pulmonary kinetics of [(13)N]nitrogen infused in saline solution in five sheep after lung lavage. The lung field was divided in six horizontal regions. MEASUREMENTS AND MAIN RESULTS: Each animal showed an inverse relation between regional shunt (Fs) and gas (Fg) fractions: Fs = -m . Fg + Fs(0). This relation was similar among animals (m = 1.25 +/- 0.14, Fs(0) = 0.75 +/- 0.15) and invariant with end-expiratory pressure, despite lack of correlation between global shunt and gas fractions and large interanimal variability in global shunt fraction. When this relation was used to estimate global shunt fraction as a perfusion-weighted average of the estimates of regional shunt fraction derived from regional gas fraction, 72% of the interanimal variability in global shunt fraction could be explained. CONCLUSIONS: Despite large interanimal variability in global shunt fraction, there was a consistent inverse relation between regional shunt and gas fractions, independent of end-expiratory pressure. Most of the interanimal variability in global shunt fraction could be explained by the combined effect of this relation and the distribution of perfusion on regional shunt, rather than by differences in global aeration.

Modeling pulmonary kinetics of 2-deoxy-2-[18F]fluoro-D-glucose during acute lung injury.

RATIONALE AND OBJECTIVES: Dynamic positron emission tomographic imaging of the radiotracer 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) is increasingly used to assess metabolic activity of lung inflammatory cells. To analyze the kinetics of (18)F-FDG in brain and tumor tissues, the Sokoloff model has been typically used. In the lungs, however, a high blood-to-parenchymal volume ratio and (18)F-FDG distribution in edematous injured tissue could require a modified model to properly describe (18)F-FDG kinetics. MATERIALS AND METHODS: We developed and validated a new model of lung (18)F-FDG kinetics that includes an extravascular/noncellular compartment in addition to blood and (18)F-FDG precursor pools for phosphorylation. Parameters obtained from this model were compared with those obtained using the Sokoloff model. We analyzed dynamic PET data from 15 sheep with smoke or ventilator-induced lung injury. RESULTS: In the majority of injured lungs, the new model provided better fit to the data than the Sokoloff model. Rate of pulmonary (18)F-FDG net uptake and distribution volume in the precursor pool for phosphorylation correlated between the two models (R(2)=0.98, 0.78), but were overestimated with the Sokoloff model by 17% (P< .05) and 16% (P< .0005) compared to the new one. The range of the extravascular/noncellular (18)F-FDG distribution volumes was up to 13% and 49% of lung tissue volume in smoke- and ventilator-induced lung injury, respectively. CONCLUSION: The lung-specific model predicted (18)F-FDG kinetics during acute lung injury more accurately than the Sokoloff model and may provide new insights in the pathophysiology of lung injury.

Image-derived input function for assessment of 18F-FDG uptake by the inflamed lung.

UNLABELLED: Pulmonary uptake of (18)F-FDG assessed with PET has been used to quantify the metabolic activity of inflammatory cells in the lung. This assessment involves modeling of tracer kinetics and knowledge of a time-activity curve in pulmonary artery plasma as an input function, usually acquired by manual blood sampling. This paper presents and validates a method to accurately derive an input function from a blood-pool region of interest (ROI) defined in dynamic PET images. METHODS: The method is based on a 2-parameter model describing the activity of blood and that from spillover into the time-activity curve for the ROI. The model parameters are determined using an iterative algorithm, with 2 blood samples used to calibrate the raw PET-derived activity data. We validated both the 2-parameter model and the method to derive a quantitative input function from ROIs defined for the cavities of the right and left heart and for the descending aorta by comparing them against the time-activity curve obtained by manual blood sampling from the pulmonary artery in lungs with acute inflammation. RESULTS: The model accurately described the time-activity curve from sampled blood. The 2-sample calibration method provided an efficient algorithm to derive input functions that were virtually identical to those sampled manually, including the fast kinetics of the early phase. The (18)F-FDG uptake rates in acutely injured lungs obtained using this method correlated well with those obtained exclusively using manual blood sampling (R(2) > 0.993). Within some bounds, the model was found quite insensitive to the timing of calibration blood samples or the exact definition of the blood-pool ROIs. CONCLUSION: Using 2 mixed venous blood samples, the method accurately assesses the entire time course of the pulmonary (18)F-FDG input function and does not require the precise geometry of a specific blood-pool ROI or a population-based input function. This method may substantially facilitate studies involving modeling of pulmonary (18)F-FDG in patients with viral or bacterial infections, pulmonary fibrosis, and chronic obstructive pulmonary disease.

PET imaging of regional 18F-FDG uptake and lung function after cigarette smoke inhalation.

UNLABELLED: Cigarette smoke is thought to promote local lung inflammation that leads to lung dysfunction. Lung neutrophilic inflammation is known to result in increased pulmonary uptake of (18)F-FDG. Using a sheep model of localized exposure to cigarette smoke, in this study we tested whether PET-imaged changes in regional intrapulmonary distribution of (18)F-FDG uptake are related to changes in regional lung function as assessed with the infused (13)NN-saline method. METHODS: Five anesthetized, mechanically ventilated sheep were exposed to unilateral inhalation of smoke from 10 tobacco cigarettes while the contralateral lung was ventilated with smoke-free gas. Two hours after the exposure, regional gas content was measured from a transmission scan; regional ventilation, perfusion, and shunt were measured from the kinetics of (13)NN-saline; and regional (18)F-FDG influx constant (K(i)) was calculated with the Patlak algorithm applied at a voxel-by-voxel level. RESULTS: K(i) was higher and more heterogeneous in the smoke-exposed lungs than in the control lungs (P < 0.05). Spatial heterogeneity of K(i) and impairment in regional lung function were quite variable among animals despite similar levels of smoke exposure. However, increases in mean K(i) correlated linearly with its spatial heterogeneity (Spearman correlation, r(s) = 0.94), and the highest levels of regional K(i) in smoke-exposed lungs and control lungs correlated with regional shunt fraction (r(s) = 0.78). Also, the heterogeneity of the ventilation-perfusion (V/Q) distribution of the smoke-exposed lungs was 10 times greater than that of the control lungs but correlated strongly with that of the control lungs (r = 0.998). CONCLUSION: Substantial interanimal variability and spatial heterogeneity in lung function and (18)F-FDG uptake seem to characterize the response to smoke exposure. The highest levels of local (18)F-FDG uptake were associated with differences in V/Q matching and shunt fraction among animals. The data also suggest that preexisting heterogeneity in V/Q could have been responsible for the large interanimal variability by affecting the heterogeneity and strength of the acute response to smoke inhalation.

Continuous cerebral autoregulation monitoring by improved cross-correlation analysis: comparison with the cuff deflation test.

OBJECTIVES: To improve the cross-correlation method for noninvasive, continuous monitoring of cerebral autoregulation, to evaluate this method in humans with intact and impaired autoregulatory capacity, and to compare it to the cuff deflation test. DESIGN AND SETTING: Prospective study in the intensive care unit of a university hospital. PATIENTS AND PARTICIPANTS: Fourteen patients with severe head injury, six patients with subarachnoid hemorrhage, and nine healthy volunteers. INTERVENTIONS AND MEASUREMENTS: Middle cerebral artery flow velocities and arterial blood pressure were monitored continuously. Aaslid's thigh cuff tests were performed and results were scored using Tiecks' model for autoregulation index. Data were then collected without any patient manipulation. The mean time delay between slow spontaneous oscillations of blood pressure and middle cerebral artery flow velocity was calculated by cross-correlation analysis. Data are expressed as median (lower/upper quartile). RESULTS: Healthy subjects had a higher autoregulation index than patients, 5.0 (5.0/5.5) vs. 3.3 (2.0/4.5). Slow oscillations of blood pressure and middle cerebral artery flow velocity showed a time delay of -2.0 s (-2.7/-1.7) in healthy subjects but were almost synchronal in patients, -0.07 s (-0.5/0.45). Inter-method agreement in diagnosing an intact or impaired cerebral autoregulation was obtained in 108 of 147 examinations of autoregulation (73.5%) and was considered moderate. CONCLUSIONS: Cross-correlation analysis may serve as a simple, noninvasive, and continuous measure of cerebral autoregulation. The time delay of -2.0[Symbol: see text]s in healthy subjects is in good agreement with other studies. Short-term autoregulation tests and monitoring techniques based on slow spontaneous oscillations should not be used interchangeably.

Contrast-enhanced multidetector-CT cholangiography after living donor liver transplantation.

BACKGROUND/AIMS: To prospectively evaluate the feasibility of postoperative contrast enhanced Multi-detector-CT cholangiography (ceMDCT-CA) in living liver donors and transplant recipients. METHODOLOGY: Fifteen donors and 11 recipients of a right hepatic lobe underwent ceMDCT-CA. Six donors were admitted to exclude biliary leakage; 9 donors and 11 recipients were examined to exclude postoperative biliary obstruction. The examination protocol included the intravenous short-infusion of 100 mL of a biliary contrast agent. CT cholangiography data was acquired with a slice thickness of 1 mm. This scan was followed by examination of the upper abdomen in a venous phase. Data sets were evaluated quantitatively by measurement of the biliary opacification, and qualitatively on the basis of a scale ranging from 1 (non-diagnostic) to 4 (excellent). Opacification was correlated with postoperative serum bilirubin level. RESULTS: CT data provided diagnostic delineation of the biliary tree in all 15 donors and seven of 11 recipients; in 4 recipients the degree of biliary opacification was non-diagnostic. Biliary opacification was generally higher in the donor collective. Four donors and 3 recipients presented a moderate focal biliary constriction without elevation of laboratory values. Six patients showed postoperative fluid collections suggestive of perihepatic biloma, however no biliary fistula could be visualized. CONCLUSIONS: CeMDCT-CA represents a promising tool to non-invasively assess the postoperative biliary morphology in living liver donors and transplant recipients.

Variability of preoperatively determined hepatic volumes in potential living liver donors.

RATIONALE AND OBJECTIVES: The aim of the study is to evaluate variability in hepatic volumes during the preoperative period in potential liver donors. MATERIALS AND METHODS: Eight potential living liver donors underwent preoperative multirow-detector computed tomographic assessment of hepatic transplant volumes twice. Intraindividual delay between the two examinations range was 3-62 days (mean, 30.1 days). Liver volumes were determined in a blinded fashion by an experienced radiologist and a transplantation surgeon. Results were compared and correlated with time of data acquisition during the day. RESULTS: Interobserver variability for assessments of liver volumes range was 6-32 mL (mean, 16 mL). Intraindividually, the difference between the two volume assessments ranged between -103 and +45 mL (mean, -19 mL), corresponding to percentages of alteration between -7.5% and +3.2%. There was no statistical correlation evident concerning volume alterations and specific time of data acquisition. CONCLUSION: Neither time of data acquisition nor waiting period for the surgical procedure seems to affect the accuracy of liver volume calculation. Apparent volume variations likely are in the range of the method error of the applied technique.

Parenchyma transection in adult live donor liver transplantation: the virtual dilemma of "where to cut". Experience based on virtual 3-dimensional computed tomography imaging reconstructions.

BACKGROUND/AIMS: Adequate venous drainage is essential to prevent parenchyma congestion in graft and remnant livers after adult live donor liver transplantation (ALDLT). The areas particularly prone to congestion are the right and left medial sectors. The purpose of our study was to evaluate two types of liver transection techniques (Cantlie, Malagó) frequently encountered in ALDLT and to determine their resulting anatomical and functional liver graft volumes. METHODOLOGY: Livers from 58 potential live liver donors were subject to a virtual 3-dimensional liver partition for right graft hepatectomy. Anatomical (post-transectional) volumes of both right graft and left remnant livers in either liver partition group were initially estimated and corresponding anatomic-GVBWR for the graft hemiliver was calculated. Additionally the potential venous drainage impairment in the medial area of the graft, which was influenced by the two different transection planes, was estimated giving the baseline for the calculation of the functional-GVBWR of the graft. RESULTS: Computer analysis showed no statistically significant differences in the anatomical volumetric parameters between the two potential types of liver partition. However, virtual liver partition following the Cantlie line showed significant decrease of functional volumetric parameters for right liver graft, due to incidental detachment of the right-sided tributaries of middle hepatic vein. CONCLUSIONS: Image-based computer assistance allows for areas at risk for devascularization or venous congestion to be identified and calculated before parenchyma transection in ALDLT. According to the results of this study, minimal modifications of the transection line can provide significant increases in functional volumetric parameters by avoiding venous congestion in the marginal zone of the graft, drained by the middle hepatic vein.

The influence of accessory right inferior hepatic veins on the venous drainage in right graft living donor liver transplantation.

BACKGROUND/AIMS: Proper venous outflow reconstruction is essential for the success of living donor liver transplantation (LDLT). It has also a decisive impact on postoperative graft dysfunction. The accessory right inferior hepatic veins (IHVs) usually drain parts of the lateral sector of the right hemiliver graft (RHL). The purpose of our study was to: (1) evaluate the drainage patterns of the IHVs in right hemiliver grafts; (2) analyze the influence of IHVs on the dominance relationships between the right and middle hepatic veins in RHL's; (3) evaluate some potential correlation between drainage patterns of IHVs and the portal vein anatomy. METHODOLOGY: We analyzed 3-dimensional CT-imaging reconstructions of 71 potential live liver donors evaluated at our Institution between January 2003 and October 2004. RESULTS: (1) Thirty-six (51%) donors had inferior hepatic veins (IHV) with detectable venous drainage territories, (2) the RHV/IHV-complex was dominant in 97% of cases, and the RHV as a single veinwithout anatomical IHV was dominant in 94% of right hemiliver grafts, (3) 27 of 71 livers (38%) showed a central (n=11) or peripheral (n=16) PV anomaly, (4) IHV provided a mean 32% of venous drainage in the right lateral sector, and in some cases drained up to 25% of the right medial sector irrespective of the PV anatomy, (5) such cases required IHV reconstruction to prevent severe tissue congestion in the right hemiliver graft. CONCLUSIONS: Accurate insight into the drainage patterns of the right and middle hepatic veins and precise knowledge of the functional volume drained by the IHV are essential when planning for the proper outflow reconstruction of right hemiliver grafts in LDLT.

Impact of virtual tumor resection and computer-assisted risk analysis on operation planning and intraoperative strategy in major hepatic resection.

HYPOTHESIS: Currently, standard planning for hepatic resection is based on the schematic description of the functional anatomy of the liver according to Couinaud, and on the evaluation of 2-dimensional computed tomographic imaging of the liver. Recent developments in image-based computer assistance allow patients' individual functional liver anatomy to be computed from mathematical analysis of standard multidetector computed tomographic scans. An intended resection can be performed virtually under realistic anatomic conditions, and the influence of different resection planes on blood supply and drainage within the remaining liver parenchyma can be calculated by a computer-assisted risk analysis. We evaluated the impact of computer-assisted risk analysis on operation planning for major hepatectomies, in particular on extent of resection or need for vascular reconstruction. DESIGN: Prospective cohort study. SETTING: Academic tertiary care referral center. PATIENTS: Twenty-five consecutive patients admitted to the hospital for major hepatectomy, of whom 4 had tumors deemed unresectable by both methods. INTERVENTIONS: Two-dimensional computed tomography was used to calculate the volume of the future liver remnant with the intended resection line manually determined, and then the volume of the future liver remnant was calculated again by computer-assisted risk analysis as the remaining liver volume not being devascularized but having both portal venous blood supply and hepatic venous drainage. MAIN OUTCOME MEASURES: The difference between the remaining functional liver volumes calculated by the 2 methods. RESULTS: The deviation between liver volumes determined by 2-dimensional computed tomography and by computer-assisted risk analysis was less than 20% in 14 of 21 patients, between 20% and 30% in 3, between 30% and 40% in 2, and 41% and 43% in 1 patient each. The most extensive deviations were found in extended left hepatectomy or when left hepatectomy was combined with additional wedge resection in the right lobe. In 7 cases, all with a deviation greater than 20%, the results of computer-assisted risk analysis led to a change of operation planning with regard to the extent of resection (n = 3) or the need for vascular reconstruction (n = 4), although in 1 of these cases resection was not performed because of peritoneal carcinomatosis. CONCLUSIONS: Image-based computer assistance allows for areas at risk for devascularization or venous congestion to be identified and precisely calculated before resection. In selected cases with small liver remnants, operation planning may be improved substantially by preoperative computer-assisted risk analysis.