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.

Risk of venous congestion in live donors of extended right liver graft.

AIM: To investigate middle hepatic vein (MHV) management in adult living donor liver transplantation and safer remnant volumes (RV). METHODS: There were 59 grafts with and 12 grafts without MHV (including 4 with MHV-5/8 reconstructions). All donors underwent our five-step protocol evaluation containing a preoperative protocol liver biopsy Congestive vs non-congestive RV, remnant-volume-body-weight ratios (RVBWR) and postoperative outcomes were evaluated in 71 right graft living donors. Dominant vs non-dominant MHV anatomy in total liver volume (d-MHV/TLV vs nd-MHV/TLV) was constellated with large/small congestion volumes (CV-index). Small for size (SFS) and non-SFS remnant considerations were based on standard cut-off- RVBWR and RV/TLV. Non-congestive RVBWR was based on non-congestive RV. RESULTS: MHV and non-MHV remnants showed no significant differences in RV, RV/TLV, RVBWR, total bilirubin, or INR. SFS-remnants with RV/TLV < 30% and non-SFS-remnants with RV/TLV ≥ 30% showed no significant differences either. RV and RVBWR for non-MHV (n = 59) and MHV-containing (n = 12) remnants were 550 ± 95 mL and 0.79 ± 0.1 mL vs 568 ± 97 mL and 0.79 ± 0.13, respectively (P = 0.423 and P = 0.919. Mean left RV/TLV was 35.8% ± 3.9%. Non-MHV (n = 59) and MHV-containing (n = 12) remnants (34.1% ± 3% vs 36% ± 4% respectively, P = 0.148. Eight SFS-remnants with RVBWR < 0.65 had a significantly smaller RV/TLV than 63 non-SFS-remnants with RVBWR ≥ 0.65 [SFS: RV/TLV 32.4% (range: 28%-35.7%) vs non-SFS: RV/TLV 36.2% (range: 26.1%-45.5%), P < 0.009. Six SFS-remnants with RV/TLV < 30% had significantly smaller RVBWR than 65 non-SFS-remnants with RV/TLV ≥ 30% (0.65 (range: 0.6-0.7) vs 0.8 (range: 0.6-1.27), P < 0.01. Two (2.8%) donors developed reversible liver failure. RVBWR and RV/TLV were concordant in 25%-33% of SFS and in 92%-94% of non-SFS remnants. MHV management options including complete MHV vs MHV-4A selective retention were necessary in n = 12 vs n = 2 remnants based on particularly risky congestive and non-congestive volume constellations. CONCLUSION: MHV procurement should consider individual remnant congestive- and non-congestive volume components and anatomy characteristics, RVBWR-RV/TLV constellation enables the identification of marginally small remnants.

Comparison of different magnetic resonance cholangiography techniques in living liver donors including Gd-EOB-DTPA enhanced T1-weighted sequences.

OBJECTIVES: Preoperative evaluation of potential living liver donors (PLLDs) includes the assessment of the biliary anatomy to avoid postoperative complications. Aim of this study was to compare T2-weighted (T2w) and Gd-EOB-DTPA enhanced T1-weighted (T1w) magnetic resonance cholangiography (MRC) techniques in the evaluation of PLLDs. MATERIALS AND METHODS: 30 PLLDs underwent MRC on a 1.5 T Magnetom Avanto (Siemens, Erlangen, Germany) using (A) 2D T2w HASTE (Half Fourier Acquisition Single Shot Turbo Spin Echo) fat saturated (fs) in axial plane, (B) 2D T2w HASTE fs thick slices in coronal plane, (C) free breathing 3D T2w TSE (turbo spin echo) RESTORE (high-resolution navigator corrected) plus (D) maximum intensity projections (MIPs), (E) T2w SPACE (sampling perfection with application optimized contrasts using different flip angle evolutions) plus (F) MIPs and (G) T2w TSE BLADE as well as Gd-EOB-DTPA T1w images without (G) and with (H) inversion recovery. Contrast enhanced CT cholangiography served as reference imaging modality. Two independent reviewers evaluated the biliary tract anatomy on a 5-point scale subjectively and objectively. Data sets were compared using a Mann-Whitney-U-test. Kappa values were also calculated. RESULTS: Source images and maximum intensity projections of 3D T2w TSE sequences (RESTORE and SPACE) proved to be best for subjective and objective evaluation directly followed by 2D HASTE sequences. Interobserver variabilities were good to excellent (k = 0.622-0.804). CONCLUSIONS: 3D T2w sequences are essential for preoperative biliary tract evaluation in potential living liver donors. Furthermore, our results underline the value of different MRCP sequence types for the evaluation of the biliary anatomy in PLLDs including Gd-EOB-DTPA enhanced T1w MRC.

Bile duct evaluation of potential living liver donors with Gd-EOB-DTPA enhanced MR cholangiography: Single-dose, double dose or half-dose contrast enhanced imaging.

INTRODUCTION: Detailed knowledge of the biliary anatomy is essential to avoid complications in living donor liver transplantation. The aim of this study was to determine the optimal dosage of Gd-EOB-DTPA for contrast-enhanced magnetic resonance cholangiography (ce-MRC) with reference to contrast-enhanced CT cholangiography (ce-CTC). MATERIALS AND METHODS: 30 potential living liver donors (PLLD) underwent both ce-CTC and ce-MRC. Ten candidates each received single, double or half-dose Gd-EOB-DTPA. Ce-MRC images with and without inversion recovery pulses (T1w±IR) were acquired 20-30min after intravenous contrast injection. Image data was quantitatively and qualitatively reviewed by two radiologists based on a on a 5-point scale. Data sets were compared using a Mann-Whitney-U-test or Wilcoxon-rank-sum-test. Kappa values were also calculated. RESULTS: All image series provided sufficient diagnostic information both showing normal biliary anatomy and variant bile ducts. Ce-CTC showed statistically significant better results compared to all ce-MRC data sets. T1w MRC with single dose Gd-EOB-DTPA proved to be superior to half and double dose in subjective and objective evaluation without a statistically significant difference. CONCLUSIONS: Ce-MRC is at any dosage inferior to ce-CTC. As far as preoperative planning of bile duct surgery is focused on the central biliary anatomy, ce-MRC can replace harmful ce-CTC strategies, anyway. Best results were seen with single dose GD-EOB-DTPA on T1w MRC+IR.

The "carving" liver partitioning technique for graft hepatectomy in live donor liver transplantation: a single-center experience.

BACKGROUND: In adult live donor liver transplantation, postoperative venous congestion of graft and remnant livers can lead to life-threatening complications. The purpose of this study was to evaluate the safety and benefits of our 3-dimensional, computed tomographic, computer-assisted donor hepatectomy using the "carving" partitioning technique. METHODS: Eighty-three consecutive adult live donor liver transplantations were performed based on data obtained from individualized preoperative 3-dimensional, computed tomographic reconstructions and virtual graft hepatectomies. RESULTS: There were 71 right and 12 left grafts. Small grafts (graft volume body weight ratio, <1.0) were used in 20 cases. We observed no clinically important differences in postoperative function between right and left grafts. Four recipients developed lethal small-for-size syndrome. Reversible small-for-size syndrome was observed in a right graft recipient and in 2 right graft donors. CONCLUSION: Preoperative 3-dimensional, computed tomographic, computer-assisted planning using virtual liver partitioning allowed for: (1) an individualized carving technique based on specific donor anatomic characteristics, (2) donor safety based on individualized patterns of venous outflow, and (3) optimized drainage of the medial area of the graft based on the preferential inclusion of the middle hepatic vein.

Contrast-enhanced ultra-high-field liver MRI: a feasibility trial.

The aim of this study was to investigate the feasibility of dynamic contrast-enhanced 7 T MRI of the liver using an eight-channel radiofrequency (RF) transmit/receive body-coil. 16 healthy subjects were examined on a 7 T MR system utilizing a custom-built eight-channel RF body-coil suitable for RF-shimming. The following data were acquired: (1) steady state free precession imaging, (2) T2w turbo spin echo imaging, (3) T1w in and opposed-phase imaging, (4) T1w 3D FLASH images pre-contrast and in arterial, portal-venous and venous phase and (5) a fat-saturated pre- and post-contrast 2D FLASH sequence. Visual evaluation of (1) the delineation of liver vasculature, (2) the overall image quality, and (3) artifact presence and consequent image impairment was performed. SNR of the liver parenchyma was measured for the contrast-enhanced 2D and 3D FLASH sequences. For statistical analysis, a Wilcoxon-Rank Test was used. Best delineation of non-enhanced liver vasculature and overall image quality was found for 2D FLASH MRI, with only slight improvement in vessel conspicuity after the application of contrast media. T2-weighted TSE imaging remained strongly impaired, falling short of diagnostic relevance and precluding a clinical application. Our results demonstrate the feasibility and diagnostic potential of dedicated contrast-enhanced 7 T liver MRI as well as the potential for non-contrast-enhanced angiographic application.

Computer-assisted surgical planning in adult-to-adult live donor liver transplantation: how much does it help? A single center experience.

BACKGROUND: Preoperative imaging and donor selection are cardinal components of adult-to-adult live donor liver transplantation (ALDLT). The purpose of this study was to evaluate our three-dimensional (3D) computed tomography image-derived computer-assisted surgical planning (3D CASP) in ALDLT. METHODS: Eighty-three consecutive ALDLTs (71 right and 12 left) were planned with 3D CASP. Graft, remnant, and total liver volume compliance were calculated and compared with actual intraoperative values. Computed risk analysis encompassing territorial liver mapping, functional (safely drained) volumes, and outflow congestion volumes in grafts and remnants allowed for the individualized management of the middle hepatic vein (MHV). RESULTS: Graft volume compliance was 13.5%±4.4%. Three small-for-size (SFS) grafts with lethal SFS syndrome (SFSS) had nonsignificant volume compliance with maximal graft volume-body weight ratios of less than 0.83. Seven SFS grafts with reversible or absent SFSS showed maximal graft volume-body weight ratios of 0.9 to 1.16. Significant differences were identified for (a) virtual graft and remnant congestion volumes of risky versus nonrisky MHV types (49%±6% and 34%±7% vs. 29%±8% and 33%±12%, P<0.001 and P<0.02, respectively) and (b) virtual mean functional versus surgical volumes of grafts (527±119 vs. 963±176 mL, P<0.0001) and remnants (419±182 vs. 640±213 mL, P<0.001). CONCLUSIONS: CASP allowed for (a) prevention of SFSS in extremely small grafts by predicting donor liver plasticity and (b) individualized MHV management for both donors and recipients based on functional graft/remnant volume analysis.

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.

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.

Analysis of 2-[Fluorine-18]-Fluoro-2-deoxy-D-glucose uptake kinetics in PET studies of pulmonary inflammation.

Dynamic positron emission tomography (PET) imaging of the lung using the radiotracer 2-[fluorine-18]-fluoro-2-deoxy-D-glucose ((18)F-FDG) is an emerging method to assess noninvasively the metabolic activity of pulmonary inflammatory cells. Nevertheless, because of the distinct functional and structural characteristics of inflamed lung tissue standard methods of (18)F-FDG analysis can be substantially limited and there is no consensus about the best method for quantification of the (18)F-FDG signal for acute or chronic inflammatory lung diseases. This article gives an overview on recent advances in quantitative analysis of (18)F-FDG uptake kinetics in non-neoplastic inflamed lung tissue.

"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.

Klatskin tumors and the accuracy of the Bismuth-Corlette classification.

The Bismuth-Corlette (BC) classification is the current preoperative standard to assess hilar cholangiocarcinomas (HC). The aim of this study is to evaluate the accuracy, sensitivity, and prognostic value of the BC classification. Data of patients undergoing resection for HC were analyzed. Endoscopic retrograde cholangiography and standard computed tomography were undertaken in all cases. Additional 3D-CT-reconstructions, magnetic resonance imaging, and percutaneous transhepatic cholangiography were obtained in selected patients. A systematic review and meta-analysis of the literature was performed. Ninety patients underwent resection of the hilar bile duct confluence, with right or left hemihepatectomy in 68 instances. The overall accuracy of the BC classification was 48 per cent. Rates of BC under- and over-estimation were 29 per cent and 23 per cent, respectively. The addition of MRI, 3D-CT-reconstructions, or percutaneous transhepatic cholangiography improved the accuracy to 49 per cent (P = 1.0), 53 per cent (P = 0.074), and 64 per cent (P < 0.001), respectively. Lowest sensitivity rates were for BC Type IIIA/IIIB tumors. Meta-analysis of published BC data corresponding to 540 patients did not reach significance. The BC classification has low accuracy and no prognostic value in cases of HC undergoing resection.

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.

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.

Hepatic venous drainage: how much can we learn from imaging studies? Anatomic-functional classification derived from three-dimensional computed tomography reconstructions.

BACKGROUND: The knowledge of "venous dominance" is essential to prevent serious venous congestion in live donor liver transplantation and extended liver resections. AIMS: The purpose of our study was to delineate our proposed anatomic-functional classification of hepatic venous drainage. METHODS: One hundred forty consecutive live liver donor candidates underwent three-dimensional computed tomography reconstructions and three-dimensional virtual hepatectomies. Five different venous dominance types were defined on drainage volumes or territories. "Risky" configurations were identified and classified. RESULTS: The right hepatic vein (RHV) was dominant for the entire liver and right hemiliver (RHH) in most (83.5%) cases irrespective of the presence of inferior (accessory) hepatic veins (IHVs). The middle hepatic vein (MHV) was dominant for the total liver (TL) in 15.5% of cases and for the RHH in 27% of cases. The left hepatic vein was almost always (92%) dominant for the left hemiliver. When associated with a large IHV drainage volume, a RHV/IHV complex dominant for the TL led to a RHH dominant MHV (mean 59.5%RHH) if the IHV was not reconstructed. CONCLUSIONS: Our proposed anatomic-functional classification provides a valuable insight into hepatic vein dominance patterns. RHH venous drainage patterns at "high risk" for venous congestion include (1) a dominant MHV for the TL and (2) a dominant RHV/IHV complex with a large IHV drainage volume.

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.

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.

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.

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.