Liver functional volumetry for portal vein embolization using a newly developed 99mTc-galactosyl human serum albumin scintigraphy SPECT-computed tomography fusion system

Differential hepatic avoidance radiation therapy: Proof of concept in hepatocellular carcinoma patients

PURPOSE

To evaluate the feasibility of a novel planning concept that differentially redistributes RT dose away from functional liver regions as defined by (99m)Tc-sulphur colloid (SC) uptake on patient SPECT/CT images.

MATERIALS AND METHODS

Ten HCC patients with different Child-Turcotte-Pugh scores (A5-B9) underwent SC SPECT/CT scans in treatment position prior to RT that were registered to planning CT scans. Proton pencil beam scanning (PBS) therapy plans were optimized to deliver 37.5-60.0Gy (RBE) over 5-15 fractions using single field uniform dose technique robust to range and setup uncertainty. Photon volumetrically modulated arc therapy (VMAT) plans were optimized to the same prescribed dose and minimum target coverage. For both treatment modalities, differential hepatic avoidance RT (DHART) plans were generated to decrease dose to functional liver volumes (FLV) defined by a range of thresholds relative to maximum SC uptake (43-90%) in the tumor-subtracted liver. Radiation dose was redistributed away from regions of increased SC uptake in each FLV by linearly scaling mean dose objectives during PBS or VMAT optimization. DHART planning feasibility was assessed by a significantly negative Spearman's rank correlation (RS) between dose difference and SC uptake. Patient, tumor, and treatment planning characteristics were tested for association to DHART planning feasibility using non-parametric Kruskal-Wallis ANOVA.

RESULTS

Compared to conventional plans, DHART plans achieved a 3% FLV dose reduction for every 10% SC uptake increase. DHART planning was feasible in the majority of patients with 60% of patients having RS<-0.5 (p<0.01, range -1.0 to 0.2) and was particularly effective in 30% of patients (RS<-0.9). Mean dose to FLV was reduced by up to 20% in these patients. Only fractionation regimen was associated with DHART planning feasibility: 15 fraction courses were more feasible than 5-6 fraction courses (RS<-0.93 vs. RS>-0.60, p<0.02).

CONCLUSION

Differential avoidance of functional liver regions defined on sulphur colloid SPECT/CT is achievable with either photon VMAT or proton PBS therapy. Further investigation with phantom studies and in a larger cohort of patients may validate the utility of DHART planning for HCC radiotherapy.

Functional assessment versus conventional volumetric assessment in the prediction of operative outcomes after major hepatectomy

PURPOSE

In this study we examined whether conventional future remnant liver volume (FR volume) or function (FR function) better predicted the operative outcome after major hepatectomy.

METHODS

Of 510 patients who underwent hepatectomy for various indications, 133 patients with major hepatectomy were enrolled in this study. FR volume and the corresponding FR function routinely were measured with a 99mTc-GSA scintigraphy single-proton emission computed tomography fusion system. FR function was defined as the future remnant liver uptake ratio of 99mTc-GSA per whole liver by single-proton emission computed tomography. FR volume or function in cases with insufficient FR volume or function required for major hepatectomy were defined as marginal.

RESULTS

Morbidity, liver dysfunction-related morbidity, and mortality after major hepatectomy occurred in 40 (30%), 10 (7.5%), and 8 (5.7%) patients, respectively. Thirty-two of the 133 patients were diagnosed as marginal using FR volume, but only 11 patients were diagnosed as marginal using FR function. These results indicated that 21 patients (16%) were switched to the safe group using functional assessment. Operative outcomes in patients with safe FR function (n = 122) were equivalent to those of patients with safe FR volume (n = 101), but patients with marginal FR function (n = 11) had substantially worse outcomes than patients with marginal FR volumes (n = 32). Logistic regression analysis identified marginal FR function, but not volume, as a risk factor for worse operative outcome after major hepatectomy. Portal vein embolization induced the substantially greater FR function compared with FR volume. Although liver volume equally corresponds to liver function under normal conditions, liver cirrhosis was greatly associated with the major discrepancy (more than 10%) in patients without portal vein embolization.

CONCLUSION

Functional assessment for future remnant liver identified patients who were eligible for curative hepatectomy despite a marginal status based on conventional volumetric assessment. Thus, marginal FR function is a better predictor of operative outcome after major hepatectomy than FR volume, especially in patients with nonhealthy liver.

Alterations in hepatic lobar function in regenerating rat liver

BACKGROUND

Ligation of a branch of the portal vein redirects portal blood to nonligated lobes resulting in lobar hypertrophy. Although the effect of portal vein ligation on liver volume is well documented, the parallel alterations in liver function are still the subject of controversy. Our aim was to assess the time-dependent reactions of regional hepatic function to portal vein ligation by selective biliary drainage.

METHODS

Male Wistar rats (n = 44) underwent 80% portal vein ligation. Before the operation as well as 1, 2, 3, 5, and 7 d after circulation, morphology and function (laboratory blood test; hepatic bile flow; plasma disappearance rate of indocyanine green; and biliary indocyanine green excretion) of the liver were examined.

RESULTS

Although portal vein ligation affected liver circulation and morphology to a great extent, serum albumin levels, bilirubin levels, and total hepatic bile flow did not change significantly after the operation. Nevertheless, plasma disappearance rate and biliary indocyanine green excretion indicated a temporary impairment of total liver function with the lowest value on the second day and normalization by the fifth day. Bile production and biliary indocyanine green excretion of ligated lobes decreased rapidly after the operation and remained persistently suppressed, whereas the secretory function of nonligated lobes--after a temporary decline--showed a greater increase than the weight of the lobes.

CONCLUSIONS

Portal vein ligation induced temporary impairment of total liver function, followed by rapid recovery mainly by reason of increase in the function of nonligated lobes. Functional increase in nonligated lobes was more pronounced than suggested by the degree of volume gain.

Tumor compression-induced portal obstruction and selective transarterial chemoembolization increase functional liver volume in the unobstructed area, facilitating successful resection of a large HCC

A 62-year-old man with hepatitis B was admitted for treatment of a large hepatocellular carcinoma. The right portal vein was completely obstructed by tumor compression. Although we initially planned a right trisectionectomy as curative hepatectomy, the percentage of future remnant liver volume (%RLV) and the percentage of functional liver volume (%RFLV) were 31.2% and 41.3%, respectively. Because %RFLV showed marginal tolerability for curative hepatectomy and %RLV was very low, we opted for transarterial chemoembolization of segment IV and the right lobe containing the tumor as an approach to selectively reduce liver volume and abolish liver function. One month later, %RLV and %RFLV had dramatically increased to 46.6% and 67.2%, resulting in curative hepatectomy. Our results suggest that tumor compression-induced portal obstruction and selective transarterial chemoembolization increase %RFLV much more than %RLV. This may represent a useful approach in preoperative management in patients with large hepatocellular carcinomas to improve %RFLV for hepatic resection.

Recent advances in estimating hepatic functional reserve in patients with chronic liver damage

Preoperative estimation of liver functional reserve is important in liver surgery to prevent postoperative liver failure. Although the hepatic functional reserve of patients with chronic liver disease is generally evaluated by measuring indocyanine green dye retention at 15 min, no standard method of estimating regional liver function has been established to date. Several recently introduced imaging modalities, such as hepatobiliary scintigraphy and magnetic resonance imaging with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid, may be used to evaluate liver function. Here, we review recent advances in estimating hepatic functional reserve, mainly by radiological modalities, in patients with chronic liver damage.

New perspectives in the assessment of future remnant liver

In order to achieve microscopic radical resection margins and thus better survival, surgical treatment of hepatic tumors has become more aggressive in the last decades, resulting in an increased rate of complex and extended liver resections. Postoperative outcomes mainly depend on the size and quality of the future remnant liver (FRL). Liver resection, when performed in the absence of sufficient FRL, inevitably leads to postresection liver failure. The current gold standard in the preoperative assessment of the FRL is computed tomography volumetry. In addition to the volume of the liver remnant after resection, postoperative function of the liver remnant is directly related to the quality of liver parenchyma. The latter is mainly influenced by underlying diseases such as cirrhosis and steatosis, which are often inaccurately defined until microscopic examination after the resection. Postresection liver failure remains a point of major concern that calls for accurate methods of preoperative FRL assessment. A wide spectrum of tests has become available in the past years, attesting to the fact that the ideal methodology has yet to be defined. The aim of this review is to discuss the current modalities available and new perspectives in the assessment of FRL in patients scheduled for major liver resection.

Liver resection for HCC: patient's selection and controversial scenarios

Liver resection is a valuable curative option for patients with hepatocellular carcinoma (HCC). Yet, the balance between the operative risk following hepatectomy for HCC occurring on chronic liver disease and the oncologic prognosis of advanced lesions have led treatment recommendations to limiting the place of liver resection to selected patients with preserved liver function harbouring early-stage tumours. However, better understanding of the natural history of both tumour and underlying liver disease, sophisticated assessment of the liver function, improvements in the preoperative management of the patients with the use of liver volume modulation, refinements in surgical technique including anatomic resection and laparoscopic approach along with tailored management of recurrences have led expert centres to better define and extend the indications for liver resection. In this setting, the reported favourable operative results and long-term outcomes following resection of HCC in a number of controversial scenarios support that current guidelines could be refined.

Assessment of hepatic functional regeneration after hepatectomy using (99m)Tc-GSA SPECT/CT fused imaging

BACKGROUND

The liver itself regenerates after hepatectomy but little is known about how much hepatic function recovers during the regeneration. The liver uptake value (LUV), calculated from Tc-99m-labeled galactosyl-human-serum-albumin ((99m)Tc-GSA) SPECT/CT fused images, is reliable and useful for evaluating hepatic function. In this study, we evaluated the clinical usefulness of LUV for estimating hepatic functional regeneration after hepatectomy.

METHODS

We enrolled 95 patients who had undergone (99m)Tc-GSA SPECT/CT tests before/on days 30 and 90 after hepatectomy. We determined the LUV from the (99m)Tc-GSA SPECT/CT images and calculated the %LUV (postoperative LUV/preoperative LUV × 100). Based on surgical procedures and histopathological damage, we divided the study population into patients with severe (n = 12) or non-severe fibrosis (n = 33) who had undergone minor hepatectomy, and patients with severe (n = 14) or non-severe fibrosis (n = 36) having major hepatectomy. On the 90th post-hepatectomy day, five patients manifested liver failure; in these patients, we analyzed the co-relation between liver failure and the results of the liver function tests performed on day 30 after surgery.

RESULTS

Although the %LUV reached 95.4 ± 12.2 % in 30 days, in patients with severe fibrosis after major hepatectomy it remained below 90 %. Patients having low %LUV (<75 %) and high serum bilirubin (>2.0 mg/dl) at 30 days showed a relative risk of liver failure of 12.0 and 4.5 (p < 0.001 and p < 0.001), respectively.

CONCLUSIONS

Although the %LUV recovered to about 95 % in all patients within 30 days after the hepatectomy, in patients with severe fibrosis having major hepatectomy, the process of recovery was delayed. The %LUV corresponded to the quality of the liver function which emerged in a later post-hepatectomy phase.

Functional discrepancy between two liver lobes after hemilobe biliary drainage in patients with jaundice and bile duct cancer: an appraisal using (99m)Tc-GSA SPECT/CT fusion imaging

PURPOSE

To determine the functional discrepancy between the two liver lobes using technetium 99m ((99m)Tc) diethylenetriamine-pentaacetic acid-galactosyl human serum albumin ( GSA diethylenetriamine-pentaacetic acid-galactosyl human serum albumin ) single photon emission computed tomography (SPECT)/computed tomography (CT) fusion imaging following preoperative biliary drainage and portal vein embolization ( PVE portal vein embolization ) in patients with jaundice who have bile duct cancer ( BDC bile duct cancer ).

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board, with waiver of informed consent. Preoperative (99m)Tc- GSA diethylenetriamine-pentaacetic acid-galactosyl human serum albumin SPECT/CT fusion images from 32 patients with extrahepatic BDC bile duct cancer were retrospectively reviewed. Patients were classified into four groups according to the extent of biliary drainage and presence of a preoperative right PVE portal vein embolization : right lobe drainage group (right drainage), bilateral lobe drainage group (bilateral drainage), left lobe drainage group (left drainage), and left lobe drainage with right PVE portal vein embolization group (left drainage with right PVE portal vein embolization ). Percentage volume and percentage function were measured in each lobe using fusion imaging. The ratio between percentage function and percentage volume (the function-to-volume ratio) was calculated for each lobe, and the results were compared among the four groups. Statistical analysis was performed with Wilcoxon signed-rank tests and Mann-Whitney U tests.

RESULTS

The median values for the function-to-volume ratio in the right drainage, bilateral drainage, left drainage, and left drainage with right PVE portal vein embolization group were 1.12, 1.05, 1.02, and 0.81 in the right lobe; and 0.51, 0.88, 0.96, and 1.17 in the left lobe. Significant differences in the function-to-volume ratio were observed among the four groups (right drainage vs bilateral drainage vs left drainage vs left drainage with right PVE portal vein embolization ; with P < .002, P = .023, and P < .002 for the right lobe and P < .001, P = .023, and P < .002 for the left lobe).

CONCLUSION

Hepatic lobar function significantly differs between the two lobes, depending on the extent of biliary drainage and the presence of portal vein embolization.

Efficacy of 3D-positron emission tomography/computed tomography for upper abdomen

Recent advancement in computed tomography (CT) enables us to obtain high spatial resolution image and made it possible to construct extensive high-definition three-dimensional (3D) images. But a lack of contrast resolution in CT alone is still remained problem. Meanwhile, as fluorodeoxyglucose-positron emission tomography (PET) can visualize tumors in high contrast, we can create 3D images fusing the accumulation in tumors on PET/CT images. Such images can play the role of a "map of body" which makes it easy to understand the anatomical information before surgery. We also try to evaluate segmental liver function by using PET/CT fusion images. By using (11) C-methionine PET/contrast-enhanced CT, superior image quality compared to single photon emission computed tomography/CT can be obtained. CT, especially with contrast enhancement for obtaining anatomical imaging information plus PET for obtaining functional imaging information is a highly compatible combination, and adding these two types information will further increase clinical usefulness.

Percentage of future liver remnant volume before portal vein embolization influences the degree of liver regeneration after hepatectomy

BACKGROUND

Clinical determinants of liver regeneration induced by portal vein embolization (PVE) and hepatectomy remain unclear. The aims of this study were to investigate how liver regeneration occurs after PVE followed by hepatectomy and to determine which factors strongly promote liver regeneration.

METHODS

Thirty-six patients who underwent both preoperative PVE and major hepatectomy were enrolled in this study. Percentage of future liver remnant volume before PVE (%FLR-pre) was compared with the remnant liver volume after PVE (%FLR-post-PVE) and on postoperative day 7 after hepatic resection (%FLR-post-HR). Clinical indicators contributing to liver regeneration induced by both PVE and hepatectomy were examined by logistic regression analysis.

RESULTS

PVE and hepatectomy caused a two-step regeneration. FLR-pre, FLR-post-PVE, and FLR-post-HR were 448, 579, and 761 cm(3), respectively. The %FLR-pre was significantly associated with liver regeneration induced by both PVE and hepatectomy (r = 0.63, p < 0.0001). Multiple regression analysis showed that only %FLR-pre was independently correlated with posthepatectomy liver regeneration (p = 0.027, odds ratio = 13.8).

CONCLUSION

After PVE and the subsequent hepatectomy, liver regeneration was accomplished in a two-step manner. Liver regeneration was strongly influenced by the %FLR-pre.

Remnant liver volume-based predictors of postoperative liver dysfunction after hepatectomy: analysis of 625 consecutive patients from a single institution

BACKGROUND

During hepatic resection, accurate estimation of remnant liver volume and hepatic function is crucial for avoiding postoperative liver failure. The purpose of this study was to identify preoperative factors related to postoperative liver dysfunction according to the percentage of future liver remnant volume (%FLR).

METHODS

A total of 625 patients who underwent hepatectomy were enrolled in this study. Total bilirubin level >50 μmol/L and/or prothrombin time index <50 % on postoperative day 5 were used as criteria for postoperative liver dysfunction (PLD). Patients were classified into 3 groups according to the %FLR: 35-60 (n = 116), 60-80 (n = 157), and >80 (n = 351). Multivariate logistic regression analysis was performed to identify factors related to postoperative liver dysfunction in each group.

RESULTS

Among the patients with 35-80 %FLR, the morbidity and mortality rates were significantly higher in patients with PLD than in patients without PLD. There was no postoperative death in patients with >80 %FLR . Multivariate analysis showed that PLD was associated with receptor index (LHL15) ≤0.93 (odds ratio [OR] = 7.96) in patients with 35-60 %FLR. The sensitivity and specificity for PLD were 87.5 and 96.1 %, respectively. In patients with 60-80 %FLR, PLD was associated with platelet count <10.0 × 10(4)/mL (OR = 6.12). The sensitivity and specificity for PLD were 73.3 and 96.2 %, respectively.

CONCLUSION

LHL15 ≤0.93 and platelet count <10.0 × 10(4)/mL are pivotal indicators for predicting PLD in patients with 35-60 %FLR and 60-80 %FLR, respectively.

CT/99mTc-GSA SPECT fusion images demonstrate functional differences between the liver lobes

AIM: To evaluate the functional differences between the 2 liver lobes in non-cirrhotic patients by using computed tomography/^99mTc-galactosyl human serum albumin (CT/^99mTc-GSA) single-photon emission computed tomography (SPECT) fusion images.

METHODS: Between December 2008 and March 2012, 264 non-cirrhotic patients underwent preoperative liver function assessment using CT/^99mTc-GSA SPECT fusion images. Of these, 30 patients, in whom the influence of a tumor on the liver parenchyma was estimated to be negligible, were selected. Specifically, the selected patients were required to meet either of the following criteria: (1) the presence of an extrahepatic tumor; or (2) presence of a single small intrahepatic tumor. These 30 patients were retrospectively analyzed to calculate the percentage volume (%Volume) and the percentage function (%Function) of each lobe. The ratio between the %Function and %Volume (function-to-volume ratio) of each lobe was also calculated, and the ratios were compared between the 2 lobes. Furthermore, the correlations between the function-to-volume ratio and each of 2 liver parameters [lobe volume and diameter ratio of the left portal vein to the right portal vein (LPV-to-RPV diameter ratio)] were investigated.

RESULTS: The median values of %Volume and %Function were 62.6% and 67.1% in the right lobe, with %Function being significantly higher than %Volume (P < 0.01). The median values of %Volume and %Function were 31.0% and 28.7% in the left lobe, with %Function being significantly lower than %Volume (P < 0.01). The function-to-volume ratios of the right lobe (1.04-1.14) were significantly higher than those of the left lobe (0.74-0.99) (P < 0.01). The function-to-volume ratio showed no significant correlation between the lobe volume in either lobe. In contrast, the function-to-volume ratio showed significant correlations with the LPV-to-RPV diameter ratio in both lobes (right lobe: negative correlation, r_s = -0.37, P = 0.048; left lobe: positive correlation, r_s = 0.71, P < 0.001). The function-to-volume ratio in the left lobe tended to be higher, and that in the right lobe tended to be lower, in accordance with the increase in the LPV-to-RPV diameter ratio.

CONCLUSION: CT/^99mTc-GSA SPECT fusion images demonstrated that the function of the left lobe was significantly decreased compared with that of the right lobe in non-cirrhotic livers.

Index of convexity: A novel liver function index using Tc-GSA scintigraphy

AIM: To investigate the clinical usefulness of a newly developed index, the “index of convexity (IOC)”, for evaluating liver functional reserve using technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin (Tc-GSA scintigraphy).

METHODS: In total, 349 patients underwent Tc-GSA scintigraphy. Dynamic planner images were obtained, and time activity curves of the liver and heart were generated and analyzed. Our focus was on the convex shape of the liver accumulation curve. We developed a method for evaluating the extent of convexity and calculated an index that we named the IOC. Clearance index and receptor index were also calculated. The correlations between each GSA index with other liver function tests and liver histopathology were evaluated.

RESULTS: Among the 3 indices generated by Tc-GSA, the IOC had the highest correlation with all other liver function tests (indocyanine green R15, albumin, prothrombin time, cholinesterase level, platelet count, and total bilirubin level). IOC can also differentiate between normal liver, chronic hepatitis, and liver cirrhosis with highest F ratio among GSA indices as determined by one-way analysis of variance. Receiver operating characteristic analysis demonstrated high diagnostic performance of IOC in the diagnosis of cirrhosis.

CONCLUSION: IOC is a very simple and reliable index for assessing liver functional reserve, which may prove to be useful in combination with the indocyanine green test for preoperative assessment of hepatic resection.

Combined measurements of serum bile acid level and splenic volume may be useful to noninvasively assess portal venous pressure

BACKGROUND

We aimed to identify a noninvasive predictor of portal venous pressure (PVP).

METHODS

We directly measured the PVP in 40 consecutive patients who underwent direct percutaneous transhepatic portal vein puncture as part of the therapeutic management for liver diseases, and we evaluated the association of the PVP with noninvasive clinical parameters. The backgrounds of the liver were normal in 13 patients, chronic hepatitis in 17, and liver cirrhosis in ten.

RESULTS

The mean PVP was 202 ± 114 mmH(2)O. In a multivariate linear regression analysis, the serum bile acid level and splenic volume showed independent positive correlations with the PVP (P < 0.001 and 0.002, respectively). The formula for estimating PVP was identified as follows: PVP (mmH(2)O) = serum bile acid (μmol/L) × 2.593 + splenic volume (cm(3)) × 0.416 + 65.929 (R(2) = 0.698). In a receiver operating characteristic (ROC) analysis, the AUC values of serum bile acid and splenic volume at a PVP of 200 mmH(2)O were 0.909 and 0.758, respectively. However, the AUC values of serum bile acid and splenic volume at a PVP of 250 mmH(2)O were 0.792 and 0.926, respectively, suggesting that the serum bile acid level and splenic volume are sensitive predictors of early and advanced portal hypertension, respectively.

CONCLUSIONS

Combined measurements of the serum bile acid level and splenic volume may be useful to noninvasively assess the PVP prior to further invasive procedures.

Liver function testing with nuclear medicine techniques is coming of age

Liver function is a broad term, as the organ participates in a multitude of different physiological and biochemical processes, including metabolic, synthetic, and detoxifying functions. However, it is the function of the hepatocyte that is central to sustaining normal life and dealing with disease states. When the liver begins to fail in severely ill patients, it forecasts a terminal outcome. However, unlike the glomerular filtration rate which clearly quantifies the key renal function, at most practice sites, there is no clinically available quantitative test for liver function. Although it is commonplace to assess indirect evidence of that function (by measuring blood levels of its end products and by-products) and to detect an acute injury (by following rising transaminases), a widely available test that would directly measure hepatocellular function is lacking. This article reviews current knowledge on liver function studies and focuses on those nuclear medicine tests available to study the whole liver and regional liver function. The clinical application driving these tests, prediction of remnant liver function after partial hepatectomy for primary liver malignancy or metastatic disease, is addressed here in detail. The test was recently validated for this specific application and was shown to be better than the current standard of practice (computed tomography volumetry), particularly in patients with hepatic comorbidities like cirrhosis, steatosis, or cholestasis. Furthermore, early assessment of regional liver function increase after preoperative portal vein embolization becomes possible with this technology. The limiting factor to a wider acceptance of this test is based on the lack of clinical software that would allow calculation of liver function parameters. This article provides information that enables a clinical nuclear medicine facility to provide this test using readily available equipment. Furthermore, it addresses emerging clinical applications that are under investigation.

Fused 99m-Tc-GSA SPECT/CT imaging for the preoperative evaluation of postoperative liver function: can the liver uptake index predict postoperative hepatic functional reserve?

PURPOSE

To evaluate the role of hepatic asialoglycoprotein receptor analysis in the preoperative estimation of postoperative hepatic functional reserve.

METHODS

We obtained technetium-99m-diethylenetriaminepentaacetic acid-galactosyl human serum albumin (99mTc-GSA) SPECT/CT fusion images in 256 patients with liver disease scheduled for hepatic resection. The liver uptake value corrected for body surface area [LUV(BSA)] and liver uptake ratio (LUR) of the remnant were preoperatively estimated based on the fused images. These values were compared with the postoperative hepatic functional reserve.

RESULTS

Significant correlations were observed between LUV(BSA), LUR, and most conventional indicators of hepatic functional reserve. Postoperatively, nonpreserved liver functional reserve was observed in 15 of the 256 patients (5.8%). Remnant LUV(BSA) showed better correlation than remnant LUR or the other indicators. No patients with remnant LUV(BSA) above 28.0 manifested poor nonpreserved functional reserve. Using a LUV(BSA) of 27.0, it was possible to predict postoperative poor hepatic functional reserve at a sensitivity of 91%, specificity of 81%, and accuracy of 81% postoperatively. According to multivariate analysis, a low remnant LUV(BSA) was the only significant independent predictor of poor hepatic functional reserve.

CONCLUSIONS

Our 99mTc-GSA SPECT/CT fusion imaging method was clinically useful for evaluating regional hepatic function and for predicting postoperative hepatic functional reserve.

A quantitative index measured on ⁹⁹mTc GSA SPECT/CT 3D fused images to evaluate severe fibrosis in patients with chronic liver disease

PURPOSE

We compared quantitative indices estimated by use of technetium-(99m) galactosyl human serum albumin ((99m)Tc-GSA) single-photon emission computed tomography (SPECT)/computed tomography (CT) fused imaging and hepatic fibrosis in patients with chronic liver disease.

MATERIALS AND METHODS

On the basis of pathological findings we divided 161 patients into non-severe and severe fibrosis groups (n = 81 and n = 80, respectively). We measured 2 indices by (99m)Tc-GSA SPECT/CT fused imaging: liver uptake value (LUV) = [radioactivity (whole liver)/radioactivity (injected)] × 100/body surface area, and functional liver index (FLI) = [radioactivity (hepatocytes)/radioactivity (injected)] × 100/liver volume. We compared these indices with biochemical and histopathological results.

RESULTS

Univariate and multivariate analyses showed that FLI, LUV, LHL15, and prothrombin time were significant independent predictors of severe fibrosis. On the basis of receiver operating characteristics analysis, the areas under curve values of FLI, LUV, LHL15, and prothrombin time for predicting severe fibrosis were 0.83, 0.73, 0.69, and 0.68, respectively. Using an FLI value of 0.053, it was possible to predict severe fibrosis with 65 % sensitivity, 88 % specificity, and 76 % accuracy.

CONCLUSION

Assessment of functional hepatocytes by use of (99m)Tc-GSA SPECT/CT fused images is useful for identifying pathological liver fibrosis.