Intraprocedural Ablation Margin Assessment by Using Ammonia Perfusion                    PET during FDG PET/CT–guided Liver Tumor Ablation: A Pilot                    Study

Shyn, Paul B.; Casadaban, Leigh C.; Sainani, Nisha I.; Sadow, Cheryl A.; Bunch, Paul M.; Levesque, Vincent M.; Kim, Chun K.; Gerbaudo, Victor H.; Silverman, Stuart G.

doi:10.1148/radiol.2018172108

Cited by 31 publications

(15 citation statements)

References 26 publications

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“…New measurement methods or software for tumor segmentation are already being investigated in some studies. 5,8,9,[12][13][14][15][16] The results were promising and improved the assessment of ablation success. Our study was able to show that conventional measurement methods are inaccurate and can lead to large interindividual differences.…”

Section: Discussionmentioning

confidence: 86%

“…[8][9][10] Other authors try to improve the intraprocedural tumor detection and the assessment of the ablation margin as a recently published study used a FDG PET/CT guided ablation for the intraprocedural determination of the safety distance and achieved good results. 11 Many authors favour the MRI for ablation margin control. 10,12 However, in most cases tumor ablation is performed under CT guidance and the safety margin is assessed in the CT images, at least in the periinterventional setting.…”

Section: Introductionmentioning

confidence: 99%

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Safety margin assessment after microwave ablation of liver tumors: inter- and intrareader variability

Schaible

Pregler

Bäumler

et al. 2020

Radiology and Oncology

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BackgroundThe aim of the study was to evaluate the inter- and intrareader variability of the safety margin assessment after microwave ablation of liver tumors using post-procedure computed tomography (CT) images as well as to determine the sensitivity and specificity of identification remnant tumor tissue.Patients and methodsA retrospective analysis of 58 patients who underwent microwave ablation (MWA) of primary or secondary liver malignancies (46 hepatocellular carcinoma, 9 metastases of a colorectal cancer and 3 metastases of pancreatic cancer) between September 2017 and June 2019 was conducted. Three readers estimated the minimal safety margin in millimeters using side-by-side comparison of the 1-day pre-ablation CT and 1-day post-ablation CT and judged whether ablation was complete or incomplete. One reader estimated the safety margin again after 6 weeks. Magnetic resonance imaging (MRI) after 6 weeks was the gold standard.ResultsThe intraclass correlation coefficient (ICC) for estimation of the minimal safety margin of all three readers was 0.357 (95%-confidence interval 0.194–0.522). The ICC for repeated assessment (reader 1) was 0.774 (95%-confidence interval 0.645–0.860). Sensitivity and specificity of the detection of complete tumor ablation, defined as no remnant tumor tissue in 6 weeks follow-up MRI, were 93%/82%/82% and 33%/17%/83%, respectively.ConclusionsIn clinical practice, the safety margin after liver tumor ablation is often assessed using side-by-side comparison of CT images. In the study, we were able to show, that this technique has a poor reliability (ICC 0.357). From our point of view, this proves the necessity of new technical procedures for the assessment of the safety distance.

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Section: Discussionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Safety margin assessment after microwave ablation of liver tumors: inter- and intrareader variability

Schaible

Pregler

Bäumler

et al. 2020

Radiology and Oncology

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“…The CT-based visualization of the central necrotic zone following thermoablation was not explicitly studied previously, as the primary focus of earlier studies was on the identification of ablation margins, overall size assessment or cross-modality comparison of CT to ultrasound, elastography or positron emission tomography (PET) 3,10,14–19 . However, since vital tissue still exists in outer ablation zones and the boundaries of the necrotic areas cannot be reliably extrapolated from the outer shape of the ablation 6,7,20 , the delineation of the outer ablation margins alone is no accurate measure of the success of ablation 9 .…”

Section: Discussionmentioning

confidence: 99%

Improved Visualization of the Necrotic Zone after Microwave Ablation Using Computed Tomography Volume Perfusion in an In Vivo Porcine Model

Bressem

Vahldiek

Erxleben

et al. 2019

Sci Rep

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After hepatic microwave ablation, the differentiation between fully necrotic and persistent vital tissue through contrast enhanced CT remains a clinical challenge. Therefore, there is a need to evaluate new imaging modalities, such as CT perfusion (CTP) to improve the visualization of coagulation necrosis. MWA and CTP were prospectively performed in five healthy pigs. After the procedure, the pigs were euthanized, and the livers explanted. Orthogonal histological slices of the ablations were stained with a vital stain, digitalized and the necrotic core was segmented. CTP maps were calculated using a dual-input deconvolution algorithm. The segmented necrotic zones were overlaid on the DICOM images to calculate the accuracy of depiction by CECT/CTP compared to the histological reference standard. A receiver operating characteristic analysis was performed to determine the agreement/true positive rate and disagreement/false discovery rate between CECT/CTP and histology. Standard CECT showed a true positive rate of 81% and a false discovery rate of 52% for display of the coagulation necrosis. Using CTP, delineation of the coagulation necrosis could be improved significantly through the display of hepatic blood volume and hepatic arterial blood flow (p < 0.001). The ratios of true positive rate/false discovery rate were 89%/25% and 90%/50% respectively. Other parameter maps showed an inferior performance compared to CECT.

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“…Previously described MRI protocols included T1weighted gradient-echo sequences prior to and following IV contrast, as well as diffusion and T2-weighted sequences. CT protocols utilized multi-detector helical CT acquisitions following IV contrast [19,20].…”

Section: Imaging Protocolsmentioning

confidence: 99%

“…Forty-five of 77 (58%) tumors in 33 of 60 (55%) procedures were treated using MWA with either a 14-or 16-G applicator (Amica; HS Medical, Boca Raton, Fla); thirty-two of 77 (42%) tumors in 27 of 60 (45%) procedures were treated using cryoablation with an average of 3.4 (range 1-9) 14-G or 17-G cryoprobes per tumor (Cryo-Hit; Galil Medical, Arden Hills, MN). Ablation protocols followed previously published methods [16,17,19].…”

Section: Pet/ct-guided Ablation and Outcomesmentioning

confidence: 99%

Assessing ablation margins of FDG-avid liver tumors during PET/CT-guided thermal ablation procedures: a retrospective study

Casadaban

Catalano

Lee

et al. 2021

Eur J Nucl Med Mol Imaging

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Background To retrospectively assess liver tumor ablation margins using intraprocedural PET/CT images from FDG PET/CTguided microwave or cryoablation procedures and to correlate minimum margin measurements with local progression outcomes. Methods Fifty-six patients (ages 36 to 85, median 62; 32 females) with 77 FDG-avid liver tumors underwent 60 FDG PET/CT guided, percutaneous microwave, or cryoablation procedures. Single breath-hold PET/CT images were used for intraprocedural assessment of the tumor ablation margin: liver tumors remained visible on PET immediately following ablation; microwave ablation zones were visible using contrast-enhanced CT; cryoablation zones (ice balls) were visible using unenhanced CT. Two readers retrospectively determined ablation margin assessability and measured the minimum ablation margin on intraprocedural PET/CT (n = 77) and postprocedural MRI (n = 56). Local tumor progression was assessed on all available follow-up imaging (1-49 months, mean 15). Local tumor progression was correlated with PET/CT minimum margin measurements using clustered survival models for 61 tumors. Results Minimum ablation margins were more often assessable using intraprocedural PET/CT (≥ 73/77 tumors, 95%) than postprocedural MRI (≤ 35/56 tumors, 63%). In 61 tumors with PET/CT-assessable margins (excluding tumors with overlapping ablations after PET/CT), there was a 6-fold increased risk of local tumor progression [hazard ratio (HR) 6.05; P = 0.004] for minimum ablation margins < 5 mm. Conclusion Breath-hold PET/CT scans, during PET/CT-guided microwave or cryoablation procedures for FDG-avid liver tumors, enable reliable intraprocedural assessment of the entire tumor ablation margin; a minimum PET/CT ablation margin threshold of 5 mm correlates well with local tumor progression outcomes.

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Intraprocedural Ablation Margin Assessment by Using Ammonia Perfusion PET during FDG PET/CT–guided Liver Tumor Ablation: A Pilot Study

Cited by 31 publications

References 26 publications

Safety margin assessment after microwave ablation of liver tumors: inter- and intrareader variability

Safety margin assessment after microwave ablation of liver tumors: inter- and intrareader variability

Improved Visualization of the Necrotic Zone after Microwave Ablation Using Computed Tomography Volume Perfusion in an In Vivo Porcine Model

Assessing ablation margins of FDG-avid liver tumors during PET/CT-guided thermal ablation procedures: a retrospective study

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