99mTc-GSA SPECT/CT fusion imaging for hepatectomy candidates with extremely deteriorated ICG value

Predictability of combining Technetium-99m-galactosyl human serum albumin single-photon emission computed tomography/computed tomography and indocyanine green clearance test for posthepatectomy liver failure

PURPOSE

To evaluate the predictive ability of combining Technetium-99m-galactosyl human serum albumin (99mTc‑GSA) single-photon emission computed tomography (SPECT)/computed tomography (CT) volume and plasma clearance rate of indocyanine green (ICGK) for posthepatectomy liver failure (PHLF).

MATERIALS AND METHODS

Fifty patients who underwent 99mTc-GSA scintigraphy as a preoperative examination for segmentectomy or more from July 2021 to June 2023 were evaluated prospectively. Patients were divided into two groups according to the presence or absence of posthepatectomy liver failure (PHLF). Total functional liver volume (t-FLV) and remnant FLV (r-FLV) were measured from 99mTc-GSA SPECT/CT image. Future liver remnant ICGK (ICGK-F) was calculated by ICGK and remnant liver volume from CT. Area under the curve (AUC) of ICGK-F, r-FLV, r-FLV/t-FLV, ICGK × r-FLV, ICGK × r-FLV/t-FLV was calculated to evaluate predictive ability of each parameter for PHLF.

RESULTS

PHLF was occurred in 7 patients. AUC of ICGK × r-FLV was significantly higher than that of ICGK-F (0.99; 95% confidence interval [CI]: 0.96-1 vs 0.82; 95%CI: 0.64-0.96; p = 0.036). There was no significant difference between the AUC of r-FLV, r-FLV/t-FLV, ICGK × r-FLV/t-FLV and that of ICGK-F, respectively.

CONCLUSION

The combination of 99mTc‑GSA SPECT/CT volume and ICGK can predict PHLF more accurately than ICGK-F.

Current status of preoperative risk assessment for posthepatectomy liver failure in patients with hepatocellular carcinoma

Liver resection is an effective therapeutic option for patients with hepatocellular carcinoma. However, posthepatectomy liver failure (PHLF) remains a major cause of hepatectomy-related mortality, and the accurate prediction of PHLF based on preoperative assessment of liver functional reserve is a critical issue. The definition of PHLF proposed by the International Study Group for Liver Surgery has gained acceptance as a standard grading criterion. Liver function can be estimated using a variety of parameters, including routine blood biochemical examinations, clinical scoring systems, dynamic liver function tests, liver stiffness and fibrosis markers, and imaging studies. The Child-Pugh score and model for end-stage liver disease scores are conventionally used for estimating liver decompensation, although the alternatively developed albumin-bilirubin score shows superior performance for predicting hepatic dysfunction. Indocyanine green clearance, a dynamic liver function test mostly used in Japan and other Asian countries, serves as a quantitative estimation of liver function reserve and helps determine indications for surgical procedures according to the estimated risk of PHLF. In an attempt to improve predictive accuracy, specific evaluation of liver fibrosis and portal hypertension has gained popularity, including liver stiffness measurements using ultrasonography or magnetic resonance elastography, as well as noninvasive fibrosis markers. Imaging modalities, including Tc-99m-labeled galactosyl serum albumin scintigraphy and gadolinium-enhanced magnetic resonance imaging, are used for preoperative evaluation in combination with liver volume. This review aims to provide an overview of the usefulness of current options for the preoperative assessment of liver function in predicting PHLF.

Indocyanine green plasma clearance rate and 99mTc-galactosyl human serum albumin single-photon emission computed tomography evaluated preoperative remnant liver

BACKGROUND

Preoperative evaluation of future remnant liver reserves is important for safe hepatectomy. If the remnant is small, preoperative portal vein embolization (PVE) is useful. Liver volume analysis has been the primary method of preoperative evaluation, although functional examination may be more accurate. We have used the functional evaluation liver using the indocyanine green plasma clearance rate (KICG) and 99mTc-galactosyl human serum albumin single-photon emission computed tomography (99mTc-GSA SPECT) for safe hepatectomy.

AIM

To analyze the safety of our institution’s system for evaluating the remnant liver reserve.

METHODS

We retrospectively reviewed the records of 23 patients who underwent preoperative PVE. Two types of remnant liver KICG were defined as follows: Anatomical volume remnant KICG (a-rem-KICG), determined as the remnant liver anatomical volume rate × KICG; and functional volume remnant KICG (f-rem-KICG), determined as the remnant liver functional volume rate based on 99mTc-GSA SPECT × KICG. If either of the remnant liver KICGs were > 0.05, a hepatectomy was performed. Perioperative factors were analyzed. We defined the marginal group as patients with a-rem-KICG of < 0.05 and a f-rem-KICG of > 0.05 and compared the postoperative outcomes between the marginal and not marginal (both a-rem-KICG and f-rem-KICG > 0.05) groups.

RESULTS

All 23 patients underwent planned hepatectomies. Right hepatectomy, right trisectionectomy and left trisectionectomy were in 16, 6 and 1 cases, respectively. The mean of blood loss and operative time were 576 mL and 474 min, respectively. The increased amount of f-rem-KICG was significantly larger than that of a-rem-KICG after PVE (0.034 vs 0.012, P = 0.0273). The not marginal and marginal groups had 17 (73.9%) and 6 (26.1%) patients, respectively. The complications of Clavian-Dindo classification grade II or higher and post-hepatectomy liver failure were observed in six (26.1%) and one (grade A, 4.3%) patient, respectively. The 90-d mortality was zero. The marginal group had no significant difference in postoperative outcomes (prothrombin time/international normalised ratio, total bilirubin, complication, post-hepatectomy liver failure, hospital stay, 90-d, and mortality) compared with the not-marginal group.

CONCLUSION

Functional evaluation of the remnant liver enabled safe hepatectomy and may extend the indication for hepatectomy after PVE treatment.

Volumetric assessment and clinical predictors of cirrhosis in patients undergoing hepatectomy for hepatocellular carcinoma with presumed normal liver function

AIM

Indocyanine green retention rate at 15 min (ICGR15) is a frequently used indicator of liver function. Herein, clinicopathological characteristics of cirrhotic patients with normal ICGR15 value (< 10%) were investigated, as these patients have risk of postoperative liver insufficiency when receiving a major hepatic resection.

METHODS

Patients undergoing hepatectomy for hepatocellular carcinoma were divided into three groups: non-cirrhotic livers (Group A, n = 112): cirrhotic livers with ICGR15 < 10% (Group B, n = 71): and cirrhotic livers with ICGR15 > 10% (Group C, n = 296). Background characteristics and surgical outcomes were compared between groups. Functional liver volume (FLV) was computed using total liver volume and signal intensity ratio. Liver parenchymal cell volume ratio was measured in non-cancerous tissue obtained from resected specimens. Univariate and multivariate analyses were performed to detect clinical characteristics correlating with cirrhotic liver pathology with normal ICGR15.

RESULTS

There was no significant difference between groups in TLV. FLV was gradually reduced from Group A toward Group C. Liver parenchymal cell volume ratio was also gradually reduced from Group A toward Group C. Multivariate analysis revealed that platelet count (< 12 × 10⁴/mm³) (p = 0.001) and prothrombin time (< 80%) (p = 0.025) were significantly associated with cirrhotic liver pathology among patients with normal ICGR15.

CONCLUSION

Our results suggested that cirrhotic liver pathology despite normal liver function was characterized by slightly decreasing liver parenchyma as well as slight degree of fibrosis. Platelet count and PT% are useful for predicting liver cirrhosis with normal ICGR15.

Nuclear imaging methods for the prediction of postoperative morbidity and mortality in patients undergoing localized, liver-directed treatments: a systematic review

Background

Several nuclear imaging methods may predict postoperative liver function and outcome, but none has achieved recommendations in clinical guidelines. The purpose of this systematic review was to summarize the existing knowledge on this topic.

Methods

MEDLINE and Web of Science were searched for studies investigating nuclear medicine imaging methods for the prediction of postoperative liver function in patients undergoing localized, liver-directed treatments. The postoperative endpoints were clinical outcome (morbidity and mortality) as well as measures of postoperative liver function, e.g., liver function assessed by biochemical tests or nuclear imaging.

Results

A total of 1352 references were identified, of which 82 fulfilled the eligibility criteria and were included in the review. Most studies (n = 63) were retrospective studies. The vast majority of studies assessed [^99mTc]Tc-galactosyl serum albumin (GSA) (n = 57) and [^99mTc]Tc-mebrofenin (n = 19). Liver resection was entirely or partly major (involved at least three segments) in 78 reports. There were notable variations in the research methodology, e.g., image acquisition, imaging variables, and endpoints. Thirty-seven studies reported on postoperative mortality, of which most reported descriptive data at the patient level. Of the four reports that performed multivariate analyses, two showed significant predictive results of isotope-based preoperative tests. Fifty-two papers presented data on postoperative liver failure. Multivariate predictive analyses were performed in eighteen trials, of which fifteen showed the significant value of nuclear medicine tests.

Conclusion

There is sparse evidence supporting the significant value of nuclear medicine imaging methods in predicting postoperative mortality. In contrast, a notable number of trials showed a significant prediction of liver failure in multivariate analyses. The research methodology was heterogeneous and exploratory in most trials. Documentation of nuclear medicine tests in this setting awaits the results of properly designed, prospective trials with the standardization of both the nuclear medicine test and endpoints.

Hepatic function assessment to predict post-hepatectomy liver failure: what can we trust? A systematic review

Post hepatectomy liver failure (PHLF) could occur even though an adequate liver volume is preserved. Liver function is not strictly related to the volume and the necessity to pre-operatively predict the future liver remnant (FLR) function is emerging, together with the wide spreading of techniques, aiming to optimize the FLR. The aim of this study was to systematically review all the available tests, to pre-operatively assess the liver function and to estimate the risk of PHLF. A systematic literature research of Medline, Embase, Scopus was performed in accordance to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, to identify all the studies available for pre-operative liver function tests to assess the risk of PHLF and/or complications. From the 1122 references retrieved, 79 were included in the review. Dynamic functional tests, such as indocyanine green test (ICG), could evaluate only global liver function, with no definition of functional capacity of the remnant. Magnetic resonance imaging (MRI) with liver-specific contrast agents enables both liver function and volume evaluation; the absence of ionizing radiation showed a better patient's compliance. Nuclear imaging studies as hepatobiliary scintigraphy (HBS) present the unique ability to allow a precise evaluation of the segmental liver function of the remnant liver. Liver volume could overestimate liver function. Several liver function tests are available to evaluate the risk of PHLF in the pre-operative setting. However, no single test alone could accurately predict PHLF. Pre-operative combination between a dynamic quantitative test, such as ICG, with MRI or HBS, should enable a more complete functional evaluation. Functional tests to predict PHLF should be chosen according to patient's characteristics, disease, and center experience.

A Novel Noninvasive Method for Predicting Liver Fibrosis by Quantifying the Estrangement of Indocyanine Green Retention Rate and Tc-99m-diethylenetriamine-penta-acetic Acid-galactosyl Human Serum Albumin Scintigraphy

BACKGROUND/AIM

Indocyanine green (ICG) clearance test is one of the most popular dynamic methods for evaluating preoperative liver function to avoid posthepatectomy liver failure (PHLF). Tc-99m-diethylenetriamine-penta-acetic acid-galactosyl human serum albumin scintigraphy (GSA) also facilitates the direct estimation of functional hepatocytes and can estimate the ICG retention rate (R15); however, in some cases, there is a discrepancy between results of a preoperative examination of ICG-R15 and the estimated ICG-R15 obtained by 99mTc-GSA (GSA-R15). This study evaluated the gap between ICG-R15 and GSA-R15 (ΔICG) for predicting background liver fibrosis in patients who underwent hepatectomy.

PATIENTS AND METHODS

Sixty-four consecutive patients who underwent hepatectomy and preoperative ICG-R15 and GSA-R15 examinations from 2016 to 2019 were retrospectively evaluated. The gap between GSA-R15 and ICG-R15 was defined as ΔICG and the factors predicting liver fibrosis were investigated.

RESULTS

In the pathologically-proven cirrhotic group, platelet counts were significantly lower and ΔICG values were significantly larger than those in the non-/early-cirrhotic group. A multivariate analysis identified a higher total bilirubin level, a higher AST level, and a larger ΔICG level as significant predictive factors for liver cirrhosis.

CONCLUSION

Larger ΔICG was found to be an independent preoperative predictor of liver fibrosis and may positively contribute to decision-making before hepatectomy to avoid PHLF.