Automatic segmentation of thoracic CT images using three deep learning models

PurposeDeep learning (DL) techniques are widely used in medical imaging and in particular for segmentation. Indeed, manual segmentation of organs at risk (OARs) is time-consuming and suffers from inter- and intra-observer segmentation variability. Image segmentation using DL has given very promising results. In this work, we present and compare the results of segmentation of OARs and a clinical target volume (CTV) in thoracic CT images using three DL models.Materials and methodsWe used CT images of 52 patients with breast cancer from a public dataset. Automatic segmentation of the lungs, the heart and a CTV was performed using three models based on the U-Net architecture. Three metrics were used to quantify and compare the segmentation results obtained with these models: the Dice similarity coefficient (DSC), the Jaccard coefficient (J) and the Hausdorff distance (HD).ResultsThe obtained values of DSC, J and HD were presented for each segmented organ and for the three models. Examples of automatic segmentation were presented and compared to the corresponding ground truth delineations. Our values were also compared to recent results obtained by other authors.ConclusionThe performance of three DL models was evaluated for the delineation of the lungs, the heart and a CTV. This study showed clearly that these 2D models based on the U-Net architecture can be used to delineate organs in CT images with a good performance compared to other models. Generally, the three models present similar performances. Using a dataset with more CT images, the three models should give better results.     

DEep learning-based rapid Spiral Image REconstruction (DESIRE) for high-resolution spiral first-pass myocardial perfusion imaging

The objective of the current study was to develop and evaluate a DEep learning-based rapid Spiral Image REconstruction (DESIRE) technique for high-resolution spiral first-pass myocardial perfusion imaging with whole-heart coverage, to provide fast and accurate image reconstruction for both single-slice (SS) and simultaneous multislice (SMS) acquisitions. Three-dimensional U-Net–based image enhancement architectures were evaluated for high-resolution spiral perfusion imaging at 3 T. The SS and SMS MB = 2 networks were trained on SS perfusion images from 156 slices from 20 subjects. Structural similarity index (SSIM), peak signal-to-noise ratio (PSNR), and normalized root mean square error (NRMSE) were assessed, and prospective images were blindly graded by two experienced cardiologists (5: excellent; 1: poor). Excellent performance was demonstrated for the proposed technique. For SS, SSIM, PSNR, and NRMSE were 0.977 [0.972, 0.982], 42.113 [40.174, 43.493] dB, and 0.102 [0.080, 0.125], respectively, for the best network. For SMS MB = 2 retrospective data, SSIM, PSNR, and NRMSE were 0.961 [0.950, 0.969], 40.834 [39.619, 42.004] dB, and 0.107 [0.086, 0.133], respectively, for the best network. The image quality scores were 4.5 [4.1, 4.8], 4.5 [4.3, 4.6], 3.5 [3.3, 4], and 3.5 [3.3, 3.8] for SS DESIRE, SS L1-SPIRiT, MB = 2 DESIRE, and MB = 2 SMS-slice-L1-SPIRiT, respectively, showing no statistically significant difference (p = 1 and p = 1 for SS and SMS, respectively) between L1-SPIRiT and the proposed DESIRE technique. The network inference time was ~100 ms per dynamic perfusion series with DESIRE, while the reconstruction time of L1-SPIRiT with GPU acceleration was ~ 30 min. It was concluded that DESIRE enabled fast and high-quality image reconstruction for both SS and SMS MB = 2 whole-heart high-resolution spiral perfusion imaging.     

Use of the double-paddle anterolateral thigh flap for locally advanced tongue carcinoma requiring second site reconstruction

BackgroundAdvanced oral tongue carcinoma can present with extension beyond the oral cavity. Operative defects after resection may involve multiple anatomical sites and significantly impact speech and swallowing. Dependence on long-term enteral feeding is not uncommon for these patients. The anterolateral thigh (ALT) flap is one of the most reliable and flexible flaps used in the reconstruction of total and subtotal tongue defects. The double-paddle flap modification may be a more suitable option for complex oral tongue defects after advanced tumor ablation.MethodsCase series of 31 patients with oral tongue squamous cell carcinoma that were classified as stage IV. The age of patients ranged from 32 to 63 years. We designed the double-paddle ALT flaps to reconstruct the two-site surgical defects (tongue defect and pharynx or neck skin defect). Postoperative viability of the flap was checked by clinical observation. The last examination was performed at 3-months after the completion of adjuvant chemoradiotherapy. The functional capacity of our patients was evaluated by three physicians (Head and Neck Surgeon, Radiation Oncologist, and Physiatrist) using a Speech Intelligibility Score and the Functional Oral Intake Scale.ResultsA total of 31 patients with surgical defects after total or subtotal tongue resection for cancer underwent double-paddle ALT flaps for reconstruction from March 2018 to December 2019. The dimension of flaps from 8 × 12 cm to 10 × 18 cm were divided into double-paddle from 8 × 5 cm to 10 × 10 cm. There was one case of pedicle thrombosis, one case of postoperative bleeding, three cases of neck infection, and six cases of salivary fistula. Our patients were seen in follow up from 6 to 36 months, with median follow-up of 23.5 months. The survival rate of ALT flap was 100%. All of our patients achieved an oral diet by 9 months after surgery. The mean score speech intelligibility was 2.74 ± 0.68 (4-point ordinal scale). The 2-year disease-free survival rate was 61.3%.ConclusionsThe double-paddle ALT flap is a reliable flap suitable for oral defects involving multiple subsites after ablative procedures. The majority of patients demonstrated acceptable functional rehabilitation.Clinical question/ level of evidenceTherapeutic, IV.     

What information can we gain from performing adaptive radiotherapy of head and neck cancer patients from the past 10 years?

The aim of the review was to present the current literature status about replanning regarding anatomical and dosimetric changes in the target and OARs in the head and neck region during radiotherapy, to discuss and to analyze factors influencing the decision for adaptive radiotherapy of head and neck cancer patients. Significant progress has been made in head and neck patients’ evaluation and qualification for adapted radiotherapy over the past ten years. Many factors leading to anatomical and dosimetric changes during treatment have been identified. Based on the literature, the most common factors triggering re-plan are weight loss, tumor and nodal changes, and parotid glands shrinkage. The fluctuations in dose distribution in the clinical area are significant predictive factors for patients’ quality of life and the possibility of recovery. It has been shown that re-planning influence clinical outcomes: local control, disease free survival and overall survival. Regarding literature studies, it seems that adaptive radiotherapy would be the most beneficial for tumors of immense volume or those in the nearest proximity of the OARs. All researchers agree that the timing of re-planning is a crucial challenge, and there are still no clear consensus guidelines for time or criteria of re-planning. Nowadays, thanks to significant technological progress, the decision is mostly made based on observation and supported with IGRT verification. Although further research is still needed, adaptive strategies are evolving and now became the state of the art of modern radiotherapy.     

Feasibility of a method for low contrast CT image quality assessment using difference detail curves for abdominal scans

This work describes a measurement method for assessing dose-related image-quality of CT scans based on the difference detail curve (DDC) method, and showcases its use in a low contrast setting. The method is based on a phantom consisting of elliptical slices of different sizes into which contrast object modules can be inserted. These modules contain contrast objects based on (synthetic) resin mixtures with sucrose (native) or sodium iodine (contrast medium). Mixing ratios are provided to achieve a range of clinically relevant CT-numbers with these materials. The phantom is characterized in terms of contrast accuracy, energy dependency and long-term drift with satisfying results. Contrast accuracy and energy dependency are similar to that of water or soft tissue. Image quality of 655 scans of the phantom acquired at 30 different clinical institutions and with 16 different CT scanner models from 4 manufacturers was assessed by calculating a difference detail curve (DDC) from evaluation of up to 5 human observers using a custom-made software (RadiVates) described in this work. Based on these measurements, inter-observer variability was quantified using a bootstrap method and was shown to be a large contributor to the overall variability. This work demonstrates that assessment of CT image quality is feasible with the aforementioned phantom and DDC method.     

舌三针联合康复训练对脑梗死后假性延髓麻痹所致构音障碍的疗效观察

目的:探讨舌三针联合康复训练对脑梗死后假性延髓麻痹所致构音障碍疗效,以期提高脑卒中后患者生命质量。方法:选取2016年12月至2019年1月海南省人民医院收治的脑梗死后假性延髓麻痹所致构音障碍患者78例进行回顾性分析,按照治疗方法不同分为对照组和观察组,每组39例。对照组常规西医+康复训练治疗,观察组在以上基础上加用舌三针治疗,均连续治疗6周。观察2组治疗前、完成治疗后血脂、Frenchay构音评分、血液流变学、言语空气动力学指标变化并比较。完成治疗后总结疗效情况。结果:1)2组治疗完成后反射、呼吸、唇、颌、软腭、喉、舌、言语评分和治疗前比较均显著上升(P<0.05),且观察组上升幅度显著高于对照组(P<0.05)。2)2组治疗完成后三酰甘油(TG)、总胆固醇(TC)、低密度脂蛋白(LDL-C)较治疗前均显著下降,高密度脂蛋白胆固醇(HDL-C)较治疗前比较均显著上升(P<0.05),且观察组上升幅度显著高于对照组(P<0.05)。3)2组治疗完成后全血高低切黏度、血浆黏度、红细胞压积较治疗前均显著下降(P<0.05),且观察组优于对照组(P<0.05)。4)对照组治疗前、完成治疗后各指标比较差异无统计学意义(P>0.05),观察组治疗完成后平均声压级(MSDV)、音调(P)、最长发声时间(MPT)、平均气流率(MFR)、声门下压(SGP)、声门阻力(GR)、发声效率(VE)较治疗前均显著升高(P<0.05),且观察组优于对照组(P<0.05)。5)观察组治愈率38.46%、总有效率89.74%,显著高于对照组治愈率23.08%、总有效率79.49%(P<0.05)。结论:舌三针联合康复训练能通过促进脑微循环,改善血脂,促进言语功能来改善脑梗死后假性延髓麻痹所致构音障碍症状,提高生命质量。