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Background: Time‐resolved magnetic resonance fingerprinting (MRF), or 4D‐MRF, has been demonstrated its feasibility in motion management in radiotherapy (RT). However, the prohibitive long acquisition time is one of challenges of the clinical implementation of 4D‐MRF. The shortening of acquisition time causes data insufficiency in each respiratory phase, leading to poor accuracies and consistencies of the predicted tissues' properties of each phase. Purpose: To develop a technique for the reconstruction of multi‐phase parametric maps in four‐dimensional magnetic resonance fingerprinting (4D‐MRF) through the optimization of local T1 and T2 sensitivities. Methods: The proposed technique employed an iterative optimization to tailor the data arrangement of each phase by manipulation of inter‐phase frames, such that the T1 and T2 sensitivities, which were quantified by the modified Minkowski distance, of the truncated signal evolution curve was maximized. The multi‐phase signal evolution curves were modified by sliding window reconstruction and inter‐phase frame sharing (SWIFS). Motion correction (MC) and dot product matching were sequentially performed on the modified signal evolution and dictionary to reconstruct the multi‐parametric maps. The proposed technique was evaluated by numerical simulations using the extended cardiac‐torso (XCAT) phantom with regular and irregular breathing patterns, and by in vivo MRF data of three health volunteers and six liver cancer patients acquired at a 3.0 T scanner. Results: In simulation study, the proposed SWIFS approach achieved the overall mean absolute percentage error (MAPE) of 8.62% ± 1.59% and 16.2% ± 3.88% for the eight‐phases T1 and T2 maps, respectively, in the sagittal view with irregular breathing patterns. In contrast, the overall MAPE of T1 and T2 maps generated by the conventional approach with multiple MRF repetitions were 22.1% ± 11.0% and 30.8% ± 14.9%, respectively. For in‐vivo study, the predicted mean T1 and T2 of liver by the proposed SWIFS approach were 795 ms ± 38.9 ms and 58.3 ms ± 11.7 ms, respectively. Conclusions: Both simulation and in vivo results showed that the approach empowered by T1 and T2 sensitivities optimization and sliding window under the shortened acquisition of MRF had superior performance in the estimation of multi‐phase T1 and T2 maps as compared to the conventional approach with oversampling of MRF data. [ABSTRACT FROM AUTHOR]

Background: Most available four‐dimensional (4D)‐magnetic resonance imaging (MRI) techniques are limited by insufficient image quality and long acquisition times or require specially designed sequences or hardware that are not available in the clinic. These limitations have greatly hindered the clinical implementation of 4D‐MRI. Purpose: This study aims to develop a fast ultra‐quality (UQ) 4D‐MRI reconstruction method using a commercially available 4D‐MRI sequence and dual‐supervised deformation estimation model (DDEM). Methods: Thirty‐nine patients receiving radiotherapy for liver tumors were included. Each patient was scanned using a time‐resolved imaging with interleaved stochastic trajectories (TWIST)–lumetric interpolated breath‐hold examination (VIBE) MRI sequence to acquire 4D‐magnetic resonance (MR) images. They also received 3D T1‐/T2‐weighted MRI scans as prior images, and UQ 4D‐MRI at any instant was considered a deformation of them. A DDEM was developed to obtain a 4D deformable vector field (DVF) from 4D‐MRI data, and the prior images were deformed using this 4D‐DVF to generate UQ 4D‐MR images. The registration accuracies of the DDEM, VoxelMorph (normalized cross‐correlation [NCC] supervised), VoxelMorph (end‐to‐end point error [EPE] supervised), and the parametric total variation (pTV) algorithm were compared. Tumor motion on UQ 4D‐MRI was evaluated quantitatively using region of interest (ROI) tracking errors, while image quality was evaluated using the contrast‐to‐noise ratio (CNR), lung–liver edge sharpness, and perceptual blur metric (PBM). Results: The registration accuracy of the DDEM was significantly better than those of VoxelMorph (NCC supervised), VoxelMorph (EPE supervised), and the pTV algorithm (all, p < 0.001), with an inference time of 69.3 ± 5.9 ms. UQ 4D‐MRI yielded ROI tracking errors of 0.79 ± 0.65, 0.50 ± 0.55, and 0.51 ± 0.58 mm in the superior–inferior, anterior–posterior, and mid–lateral directions, respectively. From the original 4D‐MRI to UQ 4D‐MRI, the CNR increased from 7.25 ± 4.89 to 18.86 ± 15.81; the lung–liver edge full‐width‐at‐half‐maximum decreased from 8.22 ± 3.17 to 3.65 ± 1.66 mm in the in‐plane direction and from 8.79 ± 2.78 to 5.04 ± 1.67 mm in the cross‐plane direction, and the PBM decreased from 0.68 ± 0.07 to 0.38 ± 0.01. Conclusion: This novel DDEM method successfully generated UQ 4D‐MR images based on a commercial 4D‐MRI sequence. It shows great promise for improving liver tumor motion management during radiation therapy. [ABSTRACT FROM AUTHOR]

Simple Summary: The optimal treatment strategy (concurrent chemoradiation (CCRT) vs. radiotherapy alone) for stage II nasopharyngeal carcinoma (NPC) in the intensity-modulated radiotherapy (IMRT) era is controversial across guidelines. A nomogram by Sun et al. was published to predict the overall survival (OS) benefit of CCRT based on a patient's clinical parameters. Using the cohort from the Hong Kong NPC1301 study, we evaluated the external validity of the nomogram and the associations between the proposed clinical factors and OS among stage II NPC patients. Use of CCRT was an insignificant predictor for OS. The nomogram lacked the predictive accuracy and should be interpreted with caution. A nomogram was recently published by Sun et al. to predict overall survival (OS) and the additional benefit of concurrent chemoradiation (CCRT) vs. radiotherapy (RT) alone, in stage II NPC treated with conventional RT. We aimed to assess the predictors of OS and to externally validate the nomogram in the IMRT era. We analyzed stage II NPC patients treated with definitive RT alone or CCRT between 2001 and 2011 under the territory-wide Hong Kong NPC Study Group 1301 study. Clinical parameters were studied using the Cox proportional hazards model to estimate OS. The nomogram by Sun et al. was applied with 1000 times bootstrap resampling to calculate the concordance index, and we compared the nomogram predicted and observed 5-year OS. There were 482 patients included. The 5-year OS was 89.0%. In the multivariable analysis, an age > 45 years was the only significant predictor of OS (HR, 1.98; 95%CI, 1.15–3.44). Other clinical parameters were insignificant, including the use of CCRT (HR, 0.99; 95%CI, 0.62–1.58). The nomogram yielded a concordance index of 0.55 (95% CI, 0.49–0.62) which lacked clinically meaningful discriminative power. The nomogram proposed by Sun et al. should be interpreted with caution when applied to stage II NPC patients in the IMRT era. The benefit of CCRT remained controversial. [ABSTRACT FROM AUTHOR]

Background: A rising number of metastatic cancer patients are receiving palliative systemic therapy close to end of life. Patients started on such treatment are typically judged by oncologists to have at least 12 weeks survival, however, accurate survival prediction on individual patients is difficult. Systemic therapy started too late may not benefit patient, but rather, adversely affect patient's quality of life and may even shorten survival due to treatment-related side effects. Our objective is to identify factors correlating with a shorter (≤6 weeks) non-malignancy related survival in metastatic cancer patients receiving palliative systemic therapy, so as to aid oncologist in the decision-making of starting treatment or not., Methods: A review of deceased metastatic cancer patients treated with palliative systemic therapy and died between January 2013 and December 2014 was carried out. They were subcategorized into dying within or after 6 weeks since starting their last line of palliative systemic therapy, and also by cause of death (malignancy-related or non-malignancy related causes). Demographics, clinical characteristics, and type of systemic therapy used were assessed using non-parametric Mann Whitney-U tests for continuous variables and χ2 tests for categorical variables. Univariable analyses were carried out to determine associations of different variables with non-malignancy related death that happened within 6 weeks of starting their last line of palliative systemic therapy. Multivariable analyses were carried out with significant factors in univariable analyses to determine their independent effect., Results: Seven hundred and fifty-four patients were analyzed. Mean age was 63.6 (range, 21-102); female 48.7%. Older age (75 years) (P=0.007) and active liver metastasis (P=0.042) were significant predictors for early (≤6 weeks) non-malignancy related death in multivariable analysis. They have 2.012 and 1.115 times higher chance respectively to die of non-malignant causes within 6 weeks since the start of their last line of palliative systemic treatment., Conclusions: Oncologists should exercise extra caution when encountering elderly patients with active liver metastasis, especially with regard to the issue of starting palliative systemic therapy.