The Impact of Diffusion-Weighted MRI on the Definition of Gross Tumor Volume in Radiotherapy of Non-Small-Cell Lung Cancer

Fleckenstein, Jochen; Jelden, Michael; Kremp, Stephanie; Jagoda, Philippe; Stroeder, Jonas; Khreish, Fadi; Ezziddin, Samer; Buecker, Arno; Rübe, Christian; Schneider, Guenther

doi:10.1371/journal.pone.0162816

Cited by 17 publications

(13 citation statements)

References 21 publications

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“…Despite these advantages, the relatively low resolution of PET (compared to CT), improper registration, and motion blurring have been recognized as limitations for contouring. MRI provides excellent soft tissue contrast, and higher image resolution than PET, but has seen limited use in target definition for lung cancer radiotherapy [19]. Hence, radiation oncologists have generally less experience with MRI than CT for target definition.…”

Section: Discussionmentioning

confidence: 99%

“…within atelectatic lung). Variations in the apparent diffusion of water molecules due to different tissue cellularity provide contrast between tumor and the surrounding tissues in DW-MRI images and ADC maps [19]. …”

Section: Discussionmentioning

confidence: 99%

“…MRI has rarely been evaluated for lung cancer target definition in radiotherapy. In a recent study, DW-MRI-based gross tumor volumes (GTVs) were reported to be as reliable as PET-CT-based GTVs [19]. …”

Section: Introductionmentioning

confidence: 99%

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Variabilities of Magnetic Resonance Imaging–, Computed Tomography–, and Positron Emission Tomography–Computed Tomography–Based Tumor and Lymph Node Delineations for Lung Cancer Radiation Therapy Planning

Karki

Saraiya

Hugo

et al. 2017

International Journal of Radiation Oncology*Biology*Physics

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Purpose Target delineation in lung cancer radiotherapy using CT and/or PET-CT is affected by large variability. MRI has excellent soft tissue visualization and better spatial resolution than PET-CT. The main purpose of this study is to analyze delineation variability for lung cancer using MRI. Methods and materials Seven physicians delineated the tumor volumes of ten patients for the following scenarios: (1) CT only; (2) PET-CT fusion images registered to CT (“clinical standard”); and (3) post-contrast T1-weighted MRI registered with diffusion-weighted MRI. To compute interobserver variability, the median surface was generated from all observers’ contours and used as the reference surface. A physician labeled the interface types (tumor to lung, atelectasis (collapsed lung), hilum, mediastinum, or chest wall) on the median surface. Contoured volumes and bidirectional local distances (BLDs) between individual observers’ contours and the reference contour were analyzed. Results CT- and MRI-based tumor volumes normalized relative to PET-CT-based volumes were31.62±0.76 (mean±SD) and 1.38±0.44, respectively. Volume differences between the imaging modalities were not significant. Between observers, the mean normalized volumes per patient averaged over all patients varied significantly by a factor of 1.6 (MRI) and 2.0 (CT and PET-CT) (p=4.10×10−5 – 3.82×10−9). The tumor-atelectasis interface had a significantly higher variability than other interfaces for all modalities combined (p=0.0006). The interfaces with the smallest uncertainties were tumor-lung (on CT) and tumor-mediastinum (on PET-CT and MRI). Conclusions While MRI-based contouring showed overall larger variability than PET-CT, contouring variability depended on the interface type and was not significantly different between modalities despite of the limited observer experience with MRI. Multimodality imaging and combining different imaging characteristics might be the best approach to define the tumor volume most accurately.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Variabilities of Magnetic Resonance Imaging–, Computed Tomography–, and Positron Emission Tomography–Computed Tomography–Based Tumor and Lymph Node Delineations for Lung Cancer Radiation Therapy Planning

Karki

Saraiya

Hugo

et al. 2017

International Journal of Radiation Oncology*Biology*Physics

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“…Though their study examined normal tissue structures rather than tumor volumes, they reported a mean mHD of 1.7 mm, similar to our findings (26). Fleckenstein et al compared lung cancer tumor volumes delineated on diffusion-weighted MRI registered to tumor volumes delineated using PET/CT and report a similar “average” Hausdorff distance of 2.25 mm (27). Furthermore, Commandeur et al investigated prostate volumes delineated on MRI vs. CT and report a Hausdorff distance of around 3 mm (28).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of PET/MRI for Tumor Volume Delineation for Head and Neck Cancer

et al. 2017

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IntroductionComputed tomography (CT), combined positron emitted tomography and CT (PET/CT), and magnetic resonance imaging (MRI) are commonly used in head and neck radiation planning. Hybrid PET/MRI has garnered attention for potential added value in cancer staging and treatment planning. Herein, we compare PET/MRI vs. planning CT for head and neck cancer gross tumor volume (GTV) delineation.Material and methodsWe prospectively enrolled patients with head and neck cancer treated with definitive chemoradiation to 60–70 Gy using IMRT. We performed pretreatment contrast-enhanced planning CT and gadolinium-enhanced PET/MRI. Primary and nodal volumes were delineated on planning CT (GTV-CT) prospectively before treatment and PET/MRI (GTV-PET/MRI) retrospectively after treatment. GTV-PET/MRI was compared to GTV-CT using separate rigid registrations for each tumor volume. The Dice similarity coefficient (DSC) metric evaluating spatial overlap and modified Hausdorff distance (mHD) evaluating mean orthogonal distance difference were calculated. Minimum dose to 95% of GTVs (D95) was compared.ResultsEleven patients were evaluable (10 oropharynx, 1 larynx). Nine patients had evaluable primary tumor GTVs and seven patients had evaluable nodal GTVs. Mean primary GTV-CT and GTV-PET/MRI size were 13.2 and 14.3 cc, with mean intersection 8.7 cc, DSC 0.63, and mHD 1.6 mm. D95 was 65.3 Gy for primary GTV-CT vs. 65.2 Gy for primary GTV-PET/MRI. Mean nodal GTV-CT and GTV-PET/MRI size were 19.0 and 23.0 cc, with mean intersection 14.4 cc, DSC 0.69, and mHD 2.3 mm. D95 was 62.3 Gy for both nodal GTV-CT and GTV-PET/MRI.ConclusionIn this series of patients with head and neck (primarily oropharynx) cancer, PET/MRI and CT-GTVs had similar volumes (though there were individual cases with larger differences) with overall small discrepancies in spatial overlap, small mean orthogonal distance differences, and similar radiation doses.

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“…Recently published studies already pointed out the bene t of DWI in chest MRI for differential diagnosis of pulmonary nodules [10] as well as for initial staging of lung cancer and evaluation of lymph node status in particular [11,12]. Furthermore, a study group could already show a good correspondance of initial tumor volume determination when comparing PET-CT and DWI [13]. However, there is only limited data about the value of DWI in the followup assessment of NSCLC after radiochemotherapy.…”

Section: Introductionmentioning

confidence: 99%

Diffusion-weighted MRI improves response assessment after definitive radiotherapy in patients with NSCLC

Jagoda

Fleckenstein

Sonnhoff

et al. 2020

Preprint

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Background Computed tomography (CT) is the standard procedure for follow-up of non-small-cell lung cancer (NSCLC) after radiochemotherapy. CT has difficulties differentiating between tumor, atelectasis and radiation induced lung toxicity (RILT). Diffusion-weighted imaging (DWI) may enable a more accurate detection of vital tumor tissue. The aim of this study was to determine the diagnostic value of MRI versus CT in the follow-up of NSCLC. Methods Twelve patients with NSCLC stages I-III scheduled for radiochemotherapy were enrolled in this prospective study. CT with i.v. contrast agent and non enhanced MRI were performed before and 3, 6 and 12 months after treatment. Standardized ROIs were used to determine the apparent diffusion weighted coefficient (ADC) within the tumor. Tumor size was assessed by the longest longitudinal diameter (LD) and tumor volume on DWI and CT. RILT was assessed on a 4-point-score in breath-triggered T2-TSE and CT. Results There was no significant difference regarding LD and tumor volume between MRI and CT (p≥ 0.6221, respectively p≥ 0.25). Evaluation of RILT showed a very high correlation between MRI and CT at 3 (r = 0.8750) and 12 months (r = 0.903). Assessment of the ADC values suggested that patients with a good tumor response have higher ADC values than non-responders. Conclusions DWI is equivalent to CT for tumor volume determination in patients with NSCLC during follow up. The extent of RILT can be reliably determined by MRI. DWI could become a beneficial method to assess tumor response more accurately. ADC values may be useful as a prognostic marker.

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The Impact of Diffusion-Weighted MRI on the Definition of Gross Tumor Volume in Radiotherapy of Non-Small-Cell Lung Cancer

Cited by 17 publications

References 21 publications

Variabilities of Magnetic Resonance Imaging–, Computed Tomography–, and Positron Emission Tomography–Computed Tomography–Based Tumor and Lymph Node Delineations for Lung Cancer Radiation Therapy Planning

Variabilities of Magnetic Resonance Imaging–, Computed Tomography–, and Positron Emission Tomography–Computed Tomography–Based Tumor and Lymph Node Delineations for Lung Cancer Radiation Therapy Planning

Evaluation of PET/MRI for Tumor Volume Delineation for Head and Neck Cancer

Diffusion-weighted MRI improves response assessment after definitive radiotherapy in patients with NSCLC

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