Anatomical contouring variability in thoracic organs at risk

McCall, Ross; MacLennan, Grayden; Taylor, Matthew; Lenards, Nishele; Nelms, Benjamin E.; Koshy, Matthew; Lemons, Jeffrey M.; Hunzeker, Ashley

doi:10.1016/j.meddos.2016.08.004

Cited by 13 publications

(15 citation statements)

References 10 publications

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“…In an interobserver contouring investigation, DSC for thoracic structures was reported to range between 0.74 for esophagus and 0.96 for lungs, with the esophagus generating the largest interobserver variability. 13 Other studies report esophagus DSC ranging from 0.7 to 0.8 and HD of approximately 10 mm. 23 , 24 , 25 Studies reporting lung contour propagation accuracy have found MDA, HD, and DSC values ranging from 1.5 to 2 mm, 20 to 25 mm, and 0.91 to 0.96, respectively.…”

Section: Discussionmentioning

confidence: 96%

“…The accuracy of each registration method was compared against recommendations set forth in the TG132 report, which recommends DSC of >0.8 to 0.9 and MDA <2 to 3 mm, depending on the treatment site. 12 , 13 …”

Section: Methodsmentioning

confidence: 99%

“…Visual inspection of the deformed images was also performed by physicians to detect any large, noticeable issues with the transformation. The accuracy of each registration method was compared against recommendations set forth in the TG132 report, which recommends DSC of >0.8 to 0.9 and MDA <2 to 3 mm, depending on the treatment site 12, 13…”

Section: Methodsmentioning

confidence: 99%

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Evaluation of Image Registration Accuracy for Tumor and Organs at Risk in the Thorax for Compliance With TG 132 Recommendations

Guy

Weiss

Che

et al. 2019

Advances in Radiation Oncology

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PurposeTo evaluate accuracy for 2 deformable image registration methods (in-house B-spline and MIM freeform) using image pairs exhibiting changes in patient orientation and lung volume and to assess the appropriateness of registration accuracy tolerances proposed by the American Association of Physicists in Medicine Task Group 132 under such challenging conditions via assessment by expert observers.Methods and MaterialsFour-dimensional computed tomography scans for 12 patients with lung cancer were acquired with patients in prone and supine positions. Tumor and organs at risk were delineated by a physician on all data sets: supine inhale (SI), supine exhale, prone inhale, and prone exhale. The SI image was registered to the other images using both registration methods. All SI contours were propagated using the resulting transformations and compared with physician delineations using Dice similarity coefficient, mean distance to agreement, and Hausdorff distance. Additionally, propagated contours were anonymized along with ground-truth contours and rated for quality by physician-observers.ResultsAveraged across all patients, the accuracy metrics investigated remained within tolerances recommended by Task Group 132 (Dice similarity coefficient >0.8, mean distance to agreement <3 mm). MIM performed better with both complex (vertebrae) and low-contrast (esophagus) structures, whereas the in-house method performed better with lungs (whole and individual lobes). Accuracy metrics worsened but remained within tolerances when propagating from supine to prone; however, the Jacobian determinant contained regions with negative values, indicating localized nonphysiologic deformations. For MIM and in-house registrations, 50% and 43.8%, respectively, of propagated contours were rated acceptable as is and 8.2% and 11.0% as clinically unacceptable.ConclusionsThe deformable image registration methods performed reliably and met recommended tolerances despite anatomically challenging cases exceeding typical interfraction variability. However, additional quality assurance measures are necessary for complex applications (eg, dose propagation). Human review rather than unsupervised implementation should always be part of the clinical registration workflow.

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Section: Discussionmentioning

confidence: 96%

Section: Methodsmentioning

confidence: 99%

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Evaluation of Image Registration Accuracy for Tumor and Organs at Risk in the Thorax for Compliance With TG 132 Recommendations

Guy

Weiss

Che

et al. 2019

Advances in Radiation Oncology

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“…Both strategies clearly rely on optimal visualization of the oesophagus. Previous studies have assessed the ability to visualise the oesophagus on tomographic imaging and have highlighted the difficulties [38][39][40][41][42]. McCall et al tested the contouring variability of 13 medical dosimetrists using three thoracic CT datasets [39].…”

Section: Discussionmentioning

confidence: 99%

Contrast enhanced oesophageal avoidance for stereotactic body radiotherapy: Barium vs. Gastrografin

Woodford

Panettieri

Ruben

et al. 2019

Technical Innovations & Patient Support in Radiation Oncolo

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Introduction: SABR may facilitate treatment in a greater proportion of locally-advanced NSCLC patients, just as it has for early-stage disease. The oesophagus is one of the key dose-limiting organs and visualization during IGRT would better ensure toxicity is avoided. As the oesophagus is poorly seen on CBCT, we assessed the extent to which this is improved using two oral contrast agents. Materials & methods: Six patients receiving radiotherapy for Stage I-III NSCLC were assigned to receive 50 mL Gastrografin or 50 mL barium sulphate prior to simulation and pre-treatment CBCTs. Three additional patients who did not receive contrast were included as a control group. Oesophageal visibility was determined by assessing concordance between six experienced observers in contouring the organ. 36 datasets and 216 contours were analysed. A STAPLE contour was created and compared to each individual contour. Descriptive statistics were used and a Kappa statistic, Dice Coefficient and Hausdorff distance were calculated and compared using a t-test. Contrast-induced artefact was assessed by observer scoring. Results: Both contrast agents significantly improved the consistency of oesophagus localisation on CBCT across all comparison metrics compared to CBCTs without contrast. Barium performed significantly better than Gastrografin with improved kappa statistics (p = 0.007), dice coefficients (p < 0.001) and Hausdorff distances (p = 0.002), although at a cost of increased image artefact. Discussion: Barium produced lower delineation uncertainties but more image artefact, compared to Gastrografin and no contrast. It is feasible to use oral contrast as a tool in IGRT to help guide clinicians and therapists with online matching and monitoring of the oesophageal position.

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“…It is also helpful for improving the quality of life and survival rate of patients. In radiotherapy for breast cancer, especially left breast cancer, heartbeat movement is the main cause of an inaccurate dose assessment of the heart and its substructures (12,13). A number of scholars have shown that deep inspiratory breath holding (DIBH) and autonomous breath control (ABC) techniques can reduce exposure from breast cancer radiotherapy (14)(15)(16)(17).…”

Section: Discussionmentioning

confidence: 99%

Study on the Effect of 4D-CT Special Reconstruction Images for Evaluation of the Cardiac Structure Dose in Radiotherapy for Breast Cancer

Gong

Qiu

et al. 2020

Front. Oncol.

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Objective: To study the dosimetric effect on special reconstruction images obtained from an electrocardiograph-gated four-dimensional computed tomography (ECG 4D-CT) series and compare it with the accumulation dose assessment of ECG 4D-CT. Methods: Fifteen patients underwent ECG 4D-CT scans to obtain a 4D-CT series. The 20 phase images of 0-95% were reconstructed at intervals of 5% of the cardiac cycle by the 4D-CT series. The 4D-CT series was specially reconstructed, and the maximum intensity projection (MIP), minimum intensity projection (MinIP), average intensity projection (AIP), and sum intensity projection (SIP) were obtained. The left ventricular muscle (LV) and the anterior descending branch of the left coronary artery (LAD) were delineated on all series. The intensity-modulated radiation therapy (IMRT) plan for left breast cancer was designed on the basis of the 0% phase, and the accumulative dose (Dose −acc) of 20 phases was obtained by deformation registration. The dose-volume indexes of the LV and LAD were compared based on different CT series. Results: The dose-volume indices of V 5 , V 30 , V 40 , D max , and D mean of the LV on MIP images were 3.8, 2.0, 0.9, 3.8, and 1.7%, respectively (relative to the Dose −acc). There was no significant difference in V 5 or D max between the MIP and Dose −acc (P > 0.05). The change rates of D max on the MinIP, SIP, and AIP images were 2.5, 3.1, and 1.5%, respectively (relative to the Dose −acc) (P < 0.05). Conclusion: In the dose-volume evaluation of the LV, V 30 , V 40 , and D mean obtained by MIP were essentially the same as those obtained by the Dose −acc and can be used instead of the 4D-CT series to evaluate dose-volume indexes.

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Anatomical contouring variability in thoracic organs at risk

Cited by 13 publications

References 10 publications

Evaluation of Image Registration Accuracy for Tumor and Organs at Risk in the Thorax for Compliance With TG 132 Recommendations

Evaluation of Image Registration Accuracy for Tumor and Organs at Risk in the Thorax for Compliance With TG 132 Recommendations

Contrast enhanced oesophageal avoidance for stereotactic body radiotherapy: Barium vs. Gastrografin

Study on the Effect of 4D-CT Special Reconstruction Images for Evaluation of the Cardiac Structure Dose in Radiotherapy for Breast Cancer

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