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Santoro-Fernandes V, Huff D, Scarpelli ML, Perk TG, Albertini MR, Perlman S, Yip SSF, Jeraj R. Development and validation of a longitudinal soft-tissue metastatic lesion matching algorithm. Phys Med Biol 2021; 66:155017. [PMID: 34261045 PMCID: PMC11329192 DOI: 10.1088/1361-6560/ac1457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/14/2021] [Indexed: 11/11/2022]
Abstract
Metastatic cancer presents with many, sometimes hundreds of metastatic lesions through the body, which often respond heterogeneously to treatment. Therefore, lesion-level assessment is necessary for a complete understanding of disease response. Lesion-level assessment typically requires manual matching of corresponding lesions, which is a tedious, subjective, and error-prone task. This study introduces a fully automated algorithm for matching of metastatic lesions in longitudinal medical images. The algorithm entails four steps: (1) image registration, (2) lesion dilation, (3) lesion clustering, and (4) linear assignment. In step (1), 3D deformable registration is used to register the scans. In step (2), lesion contours are conformally dilated. In step (3), lesion clustering is evaluated based on local metrics. In step (4), matching is assigned based on non-greedy cost minimization. The algorithm was optimized (e.g. choice of deformable registration algorithm, dilatation size) and validated on 140 scan-pairs of 32 metastatic cancer patients from two independent clinical trials, who received longitudinal PET/CT scans as part of their treatment response assessment. Registration error was evaluated using landmark distance. A sensitivity study was performed to evaluate the optimal lesion dilation magnitude. Lesion matching performance accuracy was evaluated for all patients and for a subset with high disease burden. Two investigated deformable registration approaches (whole body deformable and articulated deformable registrations) led to similar performance with the overall registration accuracy between 2.3 and 2.6 mm. The optimal dilation magnitude of 25 mm yielded almost a perfect matching accuracy of 0.98. No significant matching accuracy decrease was observed in the subset of patients with high lesion disease burden. In summary, lesion matching using our new algorithm was highly accurate and a significant improvement, when compared to previously established methods. The proposed method enables accurate automated metastatic lesion matching in whole-body longitudinal scans.
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Affiliation(s)
- Victor Santoro-Fernandes
- School of Medicine and Public Health, Department of Medical Physics, University of Wisconsin, Madison, WI, United States of America
| | - Daniel Huff
- School of Medicine and Public Health, Department of Medical Physics, University of Wisconsin, Madison, WI, United States of America
| | - Mathew L Scarpelli
- Department of Neuroimaging, Barrow Neurological Institute, Phoenix, AZ, United States of America
| | - Timothy G Perk
- School of Medicine and Public Health, Department of Medical Physics, University of Wisconsin, Madison, WI, United States of America
- AIQ Global, Madison, WI, United States of America
| | - Mark R Albertini
- School of Medicine and Public Health, Department of Medicine, University of Wisconsin, Madison, WI, United States of America
| | - Scott Perlman
- School of Medicine and Public Health, Department of Radiology, University of Wisconsin, Madison, WI, United States of America
| | - Stephen S F Yip
- AIQ Global, Madison, WI, United States of America
- School of Medicine and Public Health, Department of Radiology, University of Wisconsin, Madison, WI, United States of America
| | - Robert Jeraj
- School of Medicine and Public Health, Department of Medical Physics, University of Wisconsin, Madison, WI, United States of America
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
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Scarpelli M, Simoncic U, Perlman S, Liu G, Jeraj R. Dynamic 18F-FLT PET imaging of spatiotemporal changes in tumor cell proliferation and vasculature reveals the mechanistic actions of anti-angiogenic therapy. Phys Med Biol 2018; 63:155008. [PMID: 29978839 DOI: 10.1088/1361-6560/aad1be] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Anti-angiogenic therapies target tumor vasculature and tumor cells, thus a concurrent assessment of these targets would lead to a greater understanding of therapeutic resistance and facilitate development of improved therapeutic strategies. We utilize dynamic 3'-deoxy-3'-18F-fluorothymidine positron emission tomography (18F-FLT PET) scanning to concurrently assess changes in tumor cell proliferation and vasculature during anti-angiogenic therapy, providing insight into how these therapies may be used effectively with combination chemotherapy. Thirty-three patients with advanced solid malignancies underwent treatment with vascular endothelial growth factor receptor inhibitor (VEGFR-TKI) axitinib on an intermittent schedule (two-weeks-on/one-week-off). Patients had up to three dynamic 18F-FLT PET/CT scans: at baseline, after two weeks of continuous VEGFR-TKI treatment, and following a one week treatment break. 18F-FLT kinetics were analyzed using a two-tissue compartment kinetic model. Kinetic parameters V b and K 1 were extracted to quantify changes in tumor vasculature and the 18F-FLT flux constant K i was calculated to quantify changes in tumor cell proliferation. Two weeks of continuous axitinib exposure led to decreases in V b (median -21%, P = 0.07), K 1 (median -39%, P < 0.01), and K i (median -37%, P < 0.01), corresponding to diminished tumor vasculature and cell proliferation that may antagonize treatment with concurrent chemotherapy. Axitinib treatment breaks led to significant increases in V b (median +42%, P < 0.01), K 1 (median +46%, P < 0.01), and K i (median +39%, P < 0.01) that is suggestive of an optimal time to schedule synergistic chemotherapy. Significant negative correlations (rho ⩽ -0.70, P < 0.01) were found between changes in tumor vasculature during axitinib exposure weeks and changes in tumor vasculature during treatment breaks. Imaging with dynamic 18F-FLT PET revealed new insights relating to the interplay of vascular and proliferative pharmacodynamics of axitinib therapy, facilitating a greater understanding of the mechanistic actions of VEGFR-TKIs. Increases in tumor vasculature and cell proliferation during VEGFR-TKI treatment breaks, suggests this period is an optimal time to schedule synergistic chemotherapy and warrants further investigation.
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Affiliation(s)
- Matthew Scarpelli
- Department of Medical Physics, University of Wisconsin, 1111 Highland Ave, Madison, WI 53792, United States of America
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Pharmacodynamic study using FLT PET/CT in advanced solid malignancies treated with a sequential combination of X-82 and docetaxel. Cancer Chemother Pharmacol 2018; 82:211-219. [PMID: 29802443 DOI: 10.1007/s00280-018-3599-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/03/2018] [Indexed: 12/26/2022]
Abstract
BACKGROUND A sequential approach, synchronizing cell-cycle specific chemotherapy during VEGFR-TKI treatment breaks, may improve the therapeutic index of this combination therapy. In this study we investigate the safety/tolerability and pharmacodynamic effects of docetaxel used in sequential combination with the novel VEGFR-TKI X-82. METHODS Patients with advanced solid malignancies underwent 21-day treatment cycles with X-82 administered daily on days 1-14, a treatment break on days 15-20, and docetaxel administered on day 21. Randomization was 1:1 to either a low-dose X-82 (200 mg) or high-dose X-82 (400 mg) arm. Patients were scheduled to undergo four 3'-deoxy-3'-18F-fluorothymidine (FLT) PET/CT scans to assess changes in tumor cell proliferation. PET standardized uptake values (SUV) were summarized for tumors and changes were assessed using mixed effects models. RESULTS 14 patients were enrolled and treated with median 3.5 cycles (range 0-12). Three patients in the high-dose cohort (50%) and three patients in the low-dose cohort (38%) experienced at least one grade 3 adverse event during the study (infections, cytopenias, electrolyte abnormalities, and vascular complications). Four patients with 13 metastatic tumors underwent FLT PET/CT scanning. During the cycle 1 X-82 exposure period, tumor SUVmax decreased by - 11% (p = 0.04). After administration of docetaxel and the cycle 2 X-82 exposure period, tumor SUVmax decreased - 44% (p = 0.03). CONCLUSIONS The sequential combination of X-82 and docetaxel was safe and led to diminished FLT uptake. Further, decrease in FLT uptake during cycle 2 (X-82 plus docetaxel) was greater than in cycle 1 (X-82 alone), suggesting sequential chemotherapy enhances the pharmacodynamic effect of therapy.
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Scarpelli M, Eickhoff J, Cuna E, Perlman S, Jeraj R. Optimal transformations leading to normal distributions of positron emission tomography standardized uptake values. Phys Med Biol 2018; 63:035021. [PMID: 29235988 DOI: 10.1088/1361-6560/aaa175] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The statistical analysis of positron emission tomography (PET) standardized uptake value (SUV) measurements is challenging due to the skewed nature of SUV distributions. This limits utilization of powerful parametric statistical models for analyzing SUV measurements. An ad-hoc approach, which is frequently used in practice, is to blindly use a log transformation, which may or may not result in normal SUV distributions. This study sought to identify optimal transformations leading to normally distributed PET SUVs extracted from tumors and assess the effects of therapy on the optimal transformations. METHODS The optimal transformation for producing normal distributions of tumor SUVs was identified by iterating the Box-Cox transformation parameter (λ) and selecting the parameter that maximized the Shapiro-Wilk P-value. Optimal transformations were identified for tumor SUVmax distributions at both pre and post treatment. This study included 57 patients that underwent 18F-fluorodeoxyglucose (18F-FDG) PET scans (publically available dataset). In addition, to test the generality of our transformation methodology, we included analysis of 27 patients that underwent 18F-Fluorothymidine (18F-FLT) PET scans at our institution. RESULTS After applying the optimal Box-Cox transformations, neither the pre nor the post treatment 18F-FDG SUV distributions deviated significantly from normality (P > 0.10). Similar results were found for 18F-FLT PET SUV distributions (P > 0.10). For both 18F-FDG and 18F-FLT SUV distributions, the skewness and kurtosis increased from pre to post treatment, leading to a decrease in the optimal Box-Cox transformation parameter from pre to post treatment. There were types of distributions encountered for both 18F-FDG and 18F-FLT where a log transformation was not optimal for providing normal SUV distributions. CONCLUSION Optimization of the Box-Cox transformation, offers a solution for identifying normal SUV transformations for when the log transformation is insufficient. The log transformation is not always the appropriate transformation for producing normally distributed PET SUVs.
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Affiliation(s)
- Matthew Scarpelli
- Department of Medical Physics, University of Wisconsin, 1111 Highland Ave, Room 1005, Madison, WI 53792, United States of America
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