Longitudinal Correlations Between Intravoxel Incoherent Motion (IVIM) and Dynamic Contrast-Enhanced (DCE) MRI During Radiotherapy in Prostate Cancer Patients

Kooreman, Ernst S.; Pelt, V. van; Nowee, Marlies E.; Pos, Floris J.; Heide, Uulke A. van der; Houdt, Petra J. van

doi:10.3389/fonc.2022.897130

Cited by 13 publications

(4 citation statements)

References 47 publications

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“…23 A robust correlation between the IVIM parameter f and perfusion parameters derived from DCE or DSC (such as rCBV) remains to be validated. 24 Moreover, it is possible that the luminal content of the prostate partly contributed to f leading to an overestimation of the BV in our study.…”

Section: Discussionmentioning

confidence: 73%

Towards tumour hypoxia imaging: Incorporating relative oxygen extraction fraction mapping of prostate with multi‐parametric quantitative MRI on a 1.5T MR‐linac

Mesny,

Leporq,

Chapet

et al. 2024

J Med Imag Rad Onc

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SummaryHypoxia plays a central role in tumour radioresistance. Reliable tumour hypoxia imaging would allow the monitoring of tumour response and a more personalized adaptation of radiotherapy planning. Here, we showed a proof of concept of the feasibility and repeatability of relative oxygen extraction fraction (rOEF) mapping of prostate using multi‐parametric quantitative MRI (qMRI) achieved for the first time on a 1.5T MR‐linac. T2, T2* relaxation times maps, and intra‐voxel incoherent motion (IVIM) parametric maps mapping were computed on a 29 years old healthy volunteer. R2′ and rOEF maps were calculated based on a multi‐parametric model. Long‐term repeatability and repeatability coefficient (RC) were determined for each parameter according to QIBA recommendations. Mean values for the entire healthy prostate were 0.99 ± 0.14 × 10−3 mm/s2, 81 ± 2.1 × 10−3 mm/s2, 21.6 ± 3.6%, 92.7 ± 19.7 ms and 62.4 ± 17.3 ms for Dslow, Dfast, f, T2 and T2*, respectively. R2′ and rOEF in the prostate were 6.1 ± 3.4 s−1 and 18.2 ± 10.1% respectively. The RC of rOEF was 4.43%. Long‐term repeatability of quantitative parameters based on a test–retest ranged from 2 to 18%. qMRI parameters are measurable and repeatable on 1.5T MR LINAC. From T2, T2* and IVIM parameters maps, we were able to obtain a rOEF mapping of the prostate. These results are the first step to a non‐invasive imaging of tumour hypoxia during radiotherapy leading to a biological image‐guided adaptive radiotherapy.

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Section: Discussionmentioning

confidence: 73%

Towards tumour hypoxia imaging: Incorporating relative oxygen extraction fraction mapping of prostate with multi‐parametric quantitative MRI on a 1.5T MR‐linac

Mesny,

Leporq,

Chapet

et al. 2024

J Med Imag Rad Onc

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“…Secondly, high-quality 3T MR images can be obtained, enabling thorough morphological and biological soft-tissue evaluation. There are emerging data on functional MRI biomarkers prior to and during radiotherapy with potential prognostic relevance [ 35 , 36 , 37 ]. We believe these to be crucial advantages in favor of modular systems in order to heighten affordability and utilization.…”

Section: Discussionmentioning

confidence: 99%

Clinical Workflow of Cone Beam Computer Tomography-Based Daily Online Adaptive Radiotherapy with Offline Magnetic Resonance Guidance: The Modular Adaptive Radiotherapy System (MARS)

Kim,

Tawk,

Knoll

et al. 2024

Cancers

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Purpose: The Ethos (Varian Medical Systems) radiotherapy device combines semi-automated anatomy detection and plan generation for cone beam computer tomography (CBCT)-based daily online adaptive radiotherapy (oART). However, CBCT offers less soft tissue contrast than magnetic resonance imaging (MRI). This work aims to present the clinical workflow of CBCT-based oART with shuttle-based offline MR guidance. Methods: From February to November 2023, 31 patients underwent radiotherapy on the Ethos (Varian, Palo Alto, CA, USA) system with machine learning (ML)-supported daily oART. Moreover, patients received weekly MRI in treatment position, which was utilized for daily plan adaptation, via a shuttle-based system. Initial and adapted treatment plans were generated using the Ethos treatment planning system. Patient clinical data, fractional session times (MRI + shuttle transport + positioning, adaptation, QA, RT delivery) and plan selection were assessed for all fractions in all patients. Results: In total, 737 oART fractions were applied and 118 MRIs for offline MR guidance were acquired. Primary sites of tumors were prostate (n = 16), lung (n = 7), cervix (n = 5), bladder (n = 1) and endometrium (n = 2). The treatment was completed in all patients. The median MRI acquisition time including shuttle transport and positioning to initiation of the Ethos adaptive session was 53.6 min (IQR 46.5–63.4). The median total treatment time without MRI was 30.7 min (IQR 24.7–39.2). Separately, median adaptation, plan QA and RT times were 24.3 min (IQR 18.6–32.2), 0.4 min (IQR 0.3–1,0) and 5.3 min (IQR 4.5–6.7), respectively. The adapted plan was chosen over the scheduled plan in 97.7% of cases. Conclusion: This study describes the first workflow to date of a CBCT-based oART combined with a shuttle-based offline approach for MR guidance. The oART duration times reported resemble the range shown by previous publications for first clinical experiences with the Ethos system.

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“…also examined intravoxel incoherent motion (IVIM) and dynamic contrast enhanced (DCE) MRI changes over the course of a moderately hypofractionated RT in 20 patients, also indicating that longitudinal measurements of functional imaging parameters is feasible and could be used for response assessment in the future. 25 …”

Section: Discussionmentioning

confidence: 99%

“…24 In the context of prostate carcinoma, Habrich et al also examined intravoxel incoherent motion (IVIM) and dynamic contrast enhanced (DCE) MRI changes over the course of a moderately hypofractionated RT in 20 patients, also indicating that longitudinal measurements of functional imaging parameters is feasible and could be used for response assessment in the future. 25 However, concerning intraprostatic tumor lesions, the verification of longitudinal stability of ADC measurements on an MRL as performed in this study in a comparison to a latest generation 3 T diagnostic scanner has to the best of our knowledge not been performed yet.…”

Section: Adc As Biomarker For Response Assessment and Role Of Mrlmentioning

confidence: 94%

Longitudinal monitoring of Apparent Diffusion Coefficient (ADC) in patients with prostate cancer undergoing MR-guided radiotherapy on an MR-Linac at 1.5 T: a prospective feasibility study

Almansour

Schick

Nachbar

et al. 2023

Radiology and Oncology

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Background Hybrid MRI linear accelerators (MR-Linac) might enable individualized online adaptation of radiotherapy using quantitative MRI sequences as diffusion-weighted imaging (DWI). The purpose of this study was to investigate the dynamics of lesion apparent diffusion coefficient (ADC) in patients with prostate cancer undergoing MR-guided radiation therapy (MRgRT) on a 1.5T MR-Linac. The ADC values at a diagnostic 3T MRI scanner were used as the reference standard. Patients and and methods In this prospective single-center study, patients with biopsy-confirmed prostate cancer who underwent both an MRI exam at a 3T scanner (MRI3T) and an exam at a 1.5T MR-Linac (MRL) at baseline and during radiotherapy were included. Lesion ADC values were measured by a radiologist and a radiation oncologist on the slice with the largest lesion. ADC values were compared before vs. during radiotherapy (during the second week) on both systems via paired t-tests. Furthermore, Pearson correlation coefficient and inter-reader agreement were computed. Results A total of nine male patients aged 67 ± 6 years [range 60 – 67 years] were included. In seven patients, the cancerous lesion was in the peripheral zone, and in two patients the lesion was in the transition zone. Inter-reader reliability regarding lesion ADC measurement was excellent with an intraclass correlation coefficient of (ICC) > 0.90 both at baseline and during radiotherapy. Thus, the results of the first reader will be reported. In both systems, there was a statistically significant elevation of lesion ADC during radiotherapy (mean MRL-ADC at baseline was 0.97 ± 0.18 × 10−3 mm2/s vs. mean MRL-ADC during radiotherapy 1.38 ± 0.3 × 10−3 mm2/s, yielding a mean lesion ADC elevation of 0.41 ± 0.20 × 10−3 mm2/s, p < 0.001). Mean MRI3T-ADC at baseline was 0.78 ± 0.165 × 10−3 mm2/s vs. mean MRI3T-ADC during radiotherapy 0.99 ± 0.175 × 10−3 mm2/s, yielding a mean lesion ADC elevation of 0.21 ± 0.96 × 10−3 mm2/s p < 0.001). The absolute ADC values from MRL were consistently significantly higher than those from MRI3T at baseline and during radiotherapy (p < = 0.001). However, there was a strong positive correlation between MRL-ADC and MRI3T-ADC at baseline (r = 0.798, p = 0.01) and during radiotherapy (r = 0.863, p = 0.003). Conclusions Lesion ADC as measured on MRL increased significantly during radiotherapy and ADC measurements of lesions on both systems showed similar dynamics. This indicates that lesion ADC as measured on the MRL may be used as a biomarker for evaluation of treatment response. In contrast, absolute ADC values as calculated by the algorithm of the manufacturer of the MRL showed systematic deviations from values obtained on a diagnostic 3T MRI system. These preliminary findings are promising but need large-scale validation. Once validated, lesion ADC on MRL might be used for real-time assessment of tumor response in patients with prostate cancer undergoing MR-guided radiation therapy.

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Longitudinal Correlations Between Intravoxel Incoherent Motion (IVIM) and Dynamic Contrast-Enhanced (DCE) MRI During Radiotherapy in Prostate Cancer Patients

Cited by 13 publications

References 47 publications

Towards tumour hypoxia imaging: Incorporating relative oxygen extraction fraction mapping of prostate with multi‐parametric quantitative MRI on a 1.5T MR‐linac

Towards tumour hypoxia imaging: Incorporating relative oxygen extraction fraction mapping of prostate with multi‐parametric quantitative MRI on a 1.5T MR‐linac

Clinical Workflow of Cone Beam Computer Tomography-Based Daily Online Adaptive Radiotherapy with Offline Magnetic Resonance Guidance: The Modular Adaptive Radiotherapy System (MARS)

Longitudinal monitoring of Apparent Diffusion Coefficient (ADC) in patients with prostate cancer undergoing MR-guided radiotherapy on an MR-Linac at 1.5 T: a prospective feasibility study

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