Publications by authors named "Joana Castanheira"

8 Publications

  • Page 1 of 1

Positron Emission Tomography-Derived Metrics Predict the Probability of Local Relapse After Oligometastasis-Directed Ablative Radiation Therapy.

Adv Radiat Oncol 2022 Mar-Apr;7(2):100864. Epub 2021 Dec 5.

Department of Radiation Oncology, Champalimaud Centre for the Unknown, Lisbon, Portugal.

Purpose: Early positron emission tomography-derived metrics post-oligometastasis radioablation may predict impending local relapses (LRs), providing a basis for a timely ablation.

Methods And Materials: Positron emission tomography data of 623 lesions treated with either 24 Gy single-dose radiation therapy (SDRT) (n = 475) or 3 ×  9 Gy stereotactic body radiation therapy (SBRT) (n = 148) were analyzed in a training data set (n = 246) to obtain optimal cutoffs for pretreatment maximum standardized uptake value (SUV) and its 3-month posttreatment decline (ΔSUV) in predicting LR risk, validated in a data set unseen to testing (n = 377).

Results: At a median of 21.7 months, 91 lesions developed LRs: 39 of 475 (8.2%) after SDRT and 52 of 148 (35.1%) after SBRT. The optimal cutoff values were 12 for SUV and -75% for ΔSUV. Bivariate SUV/ΔSUV permutations rendered a 3-tiered LR risk stratification of dual-favorable (low risk), 1 adverse (intermediate risk) and dual-adverse (high risk). Actuarial 5-year local relapse-free survival rates were 93.9% versus 89.6% versus 57.1% ( < .0001) and 76.1% versus 48.3% versus 8.2% ( < .0001) for SDRT and SBRT, respectively. The SBRT area under the ROC curve was 0.71 (95% CI, 0.61-0.79) and the high-risk subgroup yielded a 76.5% true positive LR prediction rate.

Conclusions: The SBRT dual-adverse SUV/ΔSUV category LR prediction power provides a basis for prospective studies testing whether a timely ablation of impending LRs affects oligometastasis outcomes.
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http://dx.doi.org/10.1016/j.adro.2021.100864DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8752878PMC
December 2021

I-FP-CIT SPECT in dementia with Lewy bodies, Parkinson's disease and Alzheimer's disease: a new quantitative analysis of autopsy confirmed cases.

J Neurol Neurosurg Psychiatry 2021 Feb 4. Epub 2021 Feb 4.

Champalimaud Centre for the Unknown, Champalimaud Foundation, Lisboa, Portugal.

Purpose: The aim of this study was to re-evaluate the differentiation of patients with dementia with Lewy bodies (DLB) from Alzheimer's disease (AD) and Parkinson's disease (PD) using a quantitative analysis of I-FP-CIT SPECT scans.

Methods: Thirty-six patients with in vivo I-FP-CIT SPECT and neuropathological diagnoses were included. Based on neuropathological criteria, patients were further subclassified into nine AD, eight DLB, ten PD and nine with other diagnoses. An additional 16 healthy controls (HC) scanned with I-FP-CIT SPECT were also included. All images were visually assessed as normal versus abnormal uptake by consensus of five nuclear medicine physicians. Bihemispheric mean was calculated for caudate binding potential (CBP), putamen binding potential (PBP) and putamen-to-caudate ratio (PCR).

Results: Patients with DLB had significantly lower CBP and PBP than patients with AD and significantly higher PCR than patients with PD. Qualitative visual analysis of the images gave an accuracy of 88% in the evaluation of the status of the nigrostriatal pathway considering all individuals, and 96% considering only the patients with PD, AD and DLB. Quantitative analyses provided a balanced accuracy of 94%, 94% and 100% in binary classifications DLB versus AD, DLB versus PD and PD versus AD, respectively, and an accuracy of 93% in the differentiation among patients with DLB, AD and PD simultaneously. No statistically significant differences were observed between the AD and HC.

Conclusions: This study demonstrates a very high diagnostic accuracy of the quantitative analysis of(I-FP-CIT SPECT data to differentiate among patients with DLB, PD and AD.
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http://dx.doi.org/10.1136/jnnp-2020-324606DOI Listing
February 2021

Are lesion features reproducible between F-FDG PET/CT images when acquired on analog or digital PET/CT scanners?

Eur Radiol 2021 May 30;31(5):3071-3079. Epub 2020 Oct 30.

Nuclear Medicine - Radiopharmacology, Champalimaud Centre for the Unknown, Champalimaud Foundation, Av. Brasília, 1400-038, Lisbon, Portugal.

Objectives: To compare lesion features extracted from F-FDG PET/CT images acquired on analog and digital scanners, on consecutive imaging data from the same subjects.

Methods: Whole-body F-FDG PET/CT images from 55 oncological patients were acquired twice after a single F-FDG injection, with a digital and an analog PET/CT scanner, alternately. Twenty-nine subjects were examined first on the digital, and 26 first on the analog equipment. Image reconstruction was performed using manufacturer standard clinical protocols and protocols that fulfilled EARL1 specifications. Twenty-five features based on lesion standardized uptake value (SUV) and geometry were assessed. To compare these features, intraclass correlation coefficient (ICC), relative difference (RD), absolute value of RD (|RD|), and repeatability coefficient (RC) were used.

Results: In total, 323 F-FDG avid lesions were identified. High agreement (ICC > 0.75) was obtained for most of the lesion features pulled out from both scanners' imaging data, especially when reconstruction protocols fulfilled EARL1 specifications. For EARL1 reconstruction images, the features frequently used in clinics, SUV, SUV, SUV, metabolic tumor volume, and total lesion glycolysis, reached an ICC of 0.92, 0.95, 0.87, 0.98, and 0.98, and a median RD (digital-analog) of 3%, 5%, 4%, - 3% and 1%, respectively. Using standard reconstruction protocols, the ICC were 0.84, 0.93, 0.80, 0.98, and 0.98, and the RD were 20%, 11%, 13%, - 7%, and 7%, respectively.

Conclusion: Under controlled acquisition and reconstruction parameters, most of the features studied can be used for research and clinical work. This is especially important for multicenter studies and patient follow-ups.

Key Points: • Using manufacturer standard clinical reconstruction protocols, lesions SUV was significantly higher when using the digital scanner, especially the SUV that was approximately 20% higher. • High agreement was obtained for the majority of the lesion features when using reconstruction protocols that fulfilled EARL1 specifications. • Longitudinal patient studies can be performed interchangeably between digital and analog scanners when both fulfill EARL1 specifications.
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http://dx.doi.org/10.1007/s00330-020-07390-8DOI Listing
May 2021

Asymptomatic COVID-19 positive patient suspected on FDG-PET/CT.

Nucl Med Commun 2020 06;41(6):598-599

Nuclear Medicine - Radiopharmacology Department, Champalimaud Centre for the Unknown, Champalimaud Foundation.

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http://dx.doi.org/10.1097/MNM.0000000000001221DOI Listing
June 2020

Phenotype-Oriented Ablation of Oligometastatic Cancer with Single Dose Radiation Therapy.

Int J Radiat Oncol Biol Phys 2019 07 21;104(3):593-603. Epub 2019 Feb 21.

The Champalimaud Centre for the Unknown, Lisbon, Portugal; Memorial Sloan Kettering Cancer Center, New York, New York.

Purpose: The current oligometastatic (OM) model postulates that the disease evolves dynamically with sequential emergence of OM (SOM) lesions requiring successive rounds of SOM ablation to afford tumor cure. The present phase 2 study explores the ablative efficacy of 24 Gy single-dose radiation therapy (SDRT), its feasibility in diverse OM settings, and the impact of radioablation on polymetastatic (PM) dissemination.

Methods And Materials: One hundred seventy-five consecutive patients with 566 OM or SOM lesions underwent periodic positron emission tomography/computed tomography (PET/CT) imaging to stage the disease before treatment, determine tumor response, and monitor timing of PM conversion after SDRT. When 24 Gy SDRT was restricted by dose or volume constraints of serial normal organs, radioablation was diverted to a nontoxic 3×9 Gy SBRT schedule.

Results: SOM/SOMA occurred in 42% of the patients, and 24 Gy SDRT was feasible in 76% of the lesions. Despite 92% actuarial 5-year OM ablation by 24 Gy SDRT, respective PM-free survival (PMFS) was 26%, indicating PM conversion dominates over effective OM radioablation in many patients. Multivariate analysis of OM metrics derived from staging PET/CT scanning before first treatment predicted PMFS outcome after SDRT. Bivariate analysis of dichotomized high versus low baseline metric combinations of CT-derived tumor load (cutoff at 14.8 cm) and PET-derived metabolic SUV (cutoff at 6.5) yielded a 3-tiered PMFS categorization of 89%, 58% and 17% actuarial 5-year PMFS in categories 1, 2, and 3, respectively (P < .001), defining OM disease as a syndrome of diverse clinical and prognostic phenotypes.

Conclusion: Long-term risk of PM dissemination, predicted by preablation PET/CT staging, provides guidelines for phenotype-oriented OM therapy. In categories 1 and 2, radioablation should be a primary therapeutic element when pursuing tumor cure, whereas in the PM-prone category 3, radioablation should be a component of multimodal trials addressing primarily the risk of PM dissemination. PET/CT baseline staging also provides a platform for discovery of pharmacologically accessible PM drivers as targets for new phenotype-oriented treatment protocols.
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http://dx.doi.org/10.1016/j.ijrobp.2019.02.033DOI Listing
July 2019

Gastric GIST Incidentally Detected on 68Ga-PSMA-PET/CT: Correlation Between Functional Imaging and Histology.

Clin Nucl Med 2018 Dec;43(12):e488-e491

From the Department of Nuclear Medicine, Champalimaud Foundation, Lisbon, Portugal.

Prostate-specific membrane antigen (PSMA) is specific for prostate cancer cells; nevertheless when finding uptake in abnormal locations for prostate cancer metastases, it is important to consider other hypothesis, including second cancers. There are several papers about PSMA expression in many different types of cancer, but few reported expression in gastrointestinal stromal tumors (GIST). In this case, we documented the GIST lesion not only by PET/CT but also by gastroscopy and histology. Additionally, PSMA immunochemistry was performed, showing PSMA expression in tumoral GIST cells (not in endothelial cells), evidencing a good correlation between PET/CT image and histology.
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http://dx.doi.org/10.1097/RLU.0000000000002347DOI Listing
December 2018

18F-FDG Uptake in Ischemic Colitis During Follow-up of a Patient With Lung Cancer.

Clin Nucl Med 2017 Aug;42(8):e367-e370

From the Department of Nuclear Medicine, Champalimaud Foundation, Lisbon, Portugal.

A 61-year-old man with previous history of lung adenocarcinoma underwent 2 F-FDG PET/CT investigations. The first for assessment of enlarged mediastinal lymph nodes revealed an area of increased FDG uptake in the sigmoid colon (located at the right pelvis). Colonoscopy showed a segmental area of ischemic sigmoid colitis, confirmed on histology postbiopsy. The asymptomatic man had no risk factors, and no specific treatment was administered, apart from supportive measures. One year later, there was no significantly abnormal uptake on PET/CT. Incidental ischemic colitis may be demonstrated with FDG and PET/CT needing no specific therapeutic measures for resolution.
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http://dx.doi.org/10.1097/RLU.0000000000001723DOI Listing
August 2017

FDG gated cardiac PET at rest and immediately after dobutamine stress.

Eur J Nucl Med Mol Imaging 2014 May 18;41(5):1033. Epub 2014 Jan 18.

Medicina Nuclear-Radiofarmacologia, Fundação Champalimaud, Avenida Brasília, Doca de Pedrouços, 1400-038, Lisbon, Portugal,

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http://dx.doi.org/10.1007/s00259-013-2673-7DOI Listing
May 2014
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