Multimodality functional imaging using DW-MRI and 18F-FDG-PET/CT during radiation therapy for human papillomavirus negative head and neck squamous cell carcinoma: Meixoeiro Hospital of Vigo Experience

AIMTo noninvasively investigate tumor cellularity measured using diffusion-weighted magnetic resonance imaging (DW-MRI) and glucose metabolism measured by 18F-labeled fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) during radiation therapy (RT) for human papillomavirus negative (HPV-) head and neck squamous cell carcinoma (HNSCC).METHODSIn this prospective study, 6 HPV- HNSCC patients underwent a total of 34 multimodality imaging examinations DW-MRI at 1.5 T Philips MRI scanner [(n = 24) pre-, during- (2-3 wk), and post-treatment (Tx), and 18F-FDG PET/CT pre- and post-Tx (n = 10)]. All patients received RT. Monoexponential modeling of the DW-MRI data yielded the imaging metric apparent diffusion coefficient (ADC) and the mean of standardized uptake value (SUV) was measured from 18F-FDG PET uptake. All patients had a clinical follow-up as the standard of care and survival status was documented at 1 year.RESULTSThere was a strong negative correlation between the mean of pretreatment ADC (ρ = -0.67, P = 0.01) and the pretreatment 18F-FDG PET SUV. The percentage (%) change in delta (∆) ADC for primary tumors and neck nodal metastases between pre- and Wk2-3 Tx were as follows: 75.4% and 61.6%, respectively, for the patient with no evidence of disease, 27.5% and 32.7%, respectively, for those patients who were alive with disease, and 26.9% and 7.31%, respectively, for those who were dead with disease.CONCLUSIONThese results are preliminary in nature and are indicative, and not definitive, trends rendered by the imaging metrics due to the small sample size of HPV- HNSCC patients in a Meixoeiro Hospital of Vigo Experience.

Magnetic resonance imaging evaluation of head and neck involvement in IgG4-related disease

Objective:To evaluate the radiological features of IgG4-related disease(IgG4-RD)in the head and neck region.Methods:In this radiology-based study,radiological features,clinical,laboratory,pathological findings,and prognosis of nine patients with head and neck involvement diagnosed with IgG4-RD were investigated retrospectively.Results:The median age of the patients was 38 years(range:2.5-79 years),and there were six males and three females.The most common symptoms and clinical findings of the patients were eyelid and lacrimal gland swelling,painless exophthalmos,and ophthalmoplegia.The most common site of involvement on MRI was the orbit.Orbital involvement was followed by branches of the trigeminal nerve,sinonasal cavity,cervical lymph nodes,and dural involvement.The most common and remarkable imaging features were T2 hypointensity and diffuse homogeneous contrast enhancement.Conclusions:Head and neck involvement of the IgG4-RD,has specific imaging features that can help with diagnosis.Thus,early diagnosis and better outcomes can be achieved with increasing awareness of these features of this relatively new pathology.

Texture analysis on parametric maps derived from dynamic contrast-enhanced magnetic resonance imaging in head and neck cancer

AIM: To investigate the merits of texture analysis on parametric maps derived from pharmacokinetic modeling with dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) as imaging biomarkers for the prediction of treatment response in patients with head and neck squamous cell carcinoma(HNSCC). METHODS: In this retrospective study,19 HNSCC patients underwent pre- and intra-treatment DCEMRI scans at a 1.5T MRI scanner. All patients had chemo-radiation treatment. Pharmacokinetic modeling was performed on the acquired DCE-MRI images,generating maps of volume transfer rate(Ktrans) and volume fraction of the extravascular extracellular space(ve). Image texture analysis was then employed on maps of Ktrans and ve,generating two texture measures: Energy(E) and homogeneity.RESULTS: No significant changes were found for the mean and standard deviation for Ktrans and ve between pre- and intra-treatment(P > 0.09). Texture analysis revealed that the imaging biomarker E of ve was significantly higher in intra-treatment scans,relative to pretreatment scans(P < 0.04). CONCLUSION: Chemo-radiation treatment in HNSCC significantly reduces the heterogeneity of tumors.

Clinical impact of surveillance for head and neck cancer in patients with esophageal squamous cell carcinoma

To evaluate the clinical impact of surveillance for head and neck (HN) region with narrow band imaging (NBI) in patients with esophageal squamous cell carcinoma (ESCC).METHODSSince 2006, we introduced the surveillance for HN region using NBI for all patients with ESCC before treatment, and each follow-up. The patients with newly diagnosed stage I to III ESCC were enrolled and classified into two groups as follows: Group A (no surveillance for HN region); between 1992 and 2000), and Group B (surveillance for HN region with NBI; between 2006 and 2008). We comparatively evaluated the detection rate of superficial head and neck squamous cell carcinoma (HNSCC), and the serious events due to metachronous advanced HNSCC during the follow-up.RESULTSA total 561 patients (group A: 254, group B: 307) were enrolled. Synchronous superficial HNSCC was detected in 1 patient (0.3%) in group A, and in 12 (3.9%) in group B (P = 0.008). During the follow up period, metachronous HNSCC were detected in 10 patients (3.9%) in group A and in 30 patients (9.8%) in group B (P = 0.008). All metachronous lesions in group B were early stage, and 26 patients underwent local resection, however, 6 of 10 patients (60%) in group A lost their laryngeal function and died with metachronous HNSCC.CONCLUSIONSurveillance for the HN region by using NBI endoscopy increase the detection rate of early HNSCC in patients with ESCC, and led to decrease serious events related to advanced metachronous HNSCC.

Different imaging techniques in the head and neck:Assets and drawbacks

In this review,the gold standard imaging techniques for the head and neck and the latest upcoming techniques are presented,by comparing computed tomography(CT),magnetic resonance imaging and positron emission tomography-CT,as well as ultrasound,depending on the examined area.The advantages and disadvantages of each examination protocol are presented.This article illustrates the connection between the imaging technique and the examined area.Therefore,the head and neck area is divided into different sections such as bony structures,nervous system,mucous membranes and squamous epithelium,glandular tissue,and lymphatic tissue and vessels.Finally,the latest techniques in the field of head and neck imaging such as multidetector CT,dual-energy CT,flash CT,magnetic resonance angiography,spectroscopy,and diffusion tensor tractography using 3 tesla magnetic resonance are discussed.

Monitoring photodynamic therapy of head and neck malignancies with optical spectroscopies

In recent years there has been significant developments in photosensitizers(PSs), light sources and light delivery systems that have allowed decreasing the treatment time and skin phototoxicity resulting in more frequent use of photodynamic therapy(PDT) in the clinical settings. Compared to standard treatment approaches such as chemo-radiation and surgery, PDT has much reduced morbidity for head and neck malignancies and is becoming an alternative treatment option. It can be used as an adjunct therapy to other treatment modalities without any additive cumulative side effects. Surface illumination can be an option for pre-malignant and early-stage malignancies while interstitial treatment is for debulking of thick tumors in the head and neck region. PDT can achieve equivalent or greater efficacy in treating head and neck malignancies, suggesting that it may be considered as a first line therapy in the future. Despite progressive development, clinical PDT needs improvement in several topics for wider acceptance including standardization of protocols that involve the same administrated light and PS doses and establishing quantitative tools for PDT dosimetry planning and response monitoring. Quantitative measures such as optical parameters, PS concentration, tissueoxygenation and blood flow are essential for accurate PDT dosimetry as well as PDT response monitoring and assessing therapy outcome. Unlike conventional imaging modalities like magnetic resonance imaging, novel optical imaging techniques can quantify PDT-related parameters without any contrast agent administration and enable real-time assessment during PDT for providing fast feedback to clinicians. Ongoing developments in optical imaging offer the promise of optimization of PDT protocols with improved outcomes.

Usability of Deformable Image Registration for Adaptive Radiotherapy in Head and Neck Cancer and an Automatic Prediction of Replanning

Deformable image registration (DIR) has been an important component in adaptive radiotherapy (ART). Our goal was to examine the accuracy of ART using the dice similarity coefficient (DSC) and to determine the optimal timing of replanning. A total of 22 patients who underwent volume modulated arc therapy (VMAT) for head and neck (H&N) cancers were prospectively analyzed. The planning target volume (PTV) was to receive a total of 70 Gy in 33 fractions. A second planning CT scan (rescan) was performed at the 15th fraction. The DSC was calculated for each structure on both CT scans. The continuous variables to predict the need for replanning were assessed. The optimal cut-off value was determined using receiver operating characteristic (ROC) curve analysis. In the correlation between body weight loss and DSC of each structure, weight loss correlated negatively with DSC of the whole face (rs = -0.45) and the face surface (rs = -0.51). Patients who required replanning tended to have experienced rapid weight loss. The threshold DSC was 0.98 and 0.60 in the whole face and the face surface, respectively. Patients who showed low DSC in the whole face and the face surface required replanning at a significantly high rate (P < 0.05 and P < 0.01). Weight loss correlated with DSC in both the whole face and the face surface (P < 0.05 and P < 0.05). The DSC values in the face predicted the need for replanning. In addition, weight loss tended to correlate with DSC. DIR during ART was found to be a useful tool for replanning.

VISUALIZATION OF HEAD AND NECK CANCER MODELS WITH A TRIPLE FUSION REPORTER GENE

The development of experimental animal models for head and neck tumors generally rely on the biol uminescence imaging to achieve the dynamic monitoring of the tumor growth and metastasis due to the complicated anatomical structures.Since the bioluminescence imaging is largely affected by the intracellular luciferase expression level and external D-luciferin concentrations,its imaging accuracy requires further confirmation.Here,a new triple fusion reportelr gene,which consists of a herpes simplex virus type 1 thymidine kinase(TK)gene for radioactive imaging,a far-red fuorescent protein(mLumin)gene for fuorescent imaging,and a firefly luciferase gene for bioluminescence imaging,was introduced for in vrivo observation of the head and neck tumors through multi-modality imaging.Results show that fuorescence and bioluminescence signals from mLumin and luciferase,respectively,were clearly observed in tumor cells,and TK could activate suicide pathway of the cells in the presence of nucleotide analog-ganciclovir(GCV),demonstrating the effecti veness of individual functions of each gene.Moreover,subcutaneous and metastasis animal models for head and neck tumors using the fusion reporter gene-expressing cell lines were established,allowing multi-modality imaging in vio.Together,the established tumor models of head and neck cancer based on the newly developed triple fusion reporter gene are ideal for monitoring tumor growth,assessing the drug therapeutic efficacy and verifying the effec-tiveness of new treatments.

The Comparison of Diagnostic Significance of Narrow Band Imaging in Contrast of White Light Endoscopy in the Assessment of Nasopharyngeal Cancer

Background: Narrow band imaging (NBI) is reported to improve the diagnostic importance of nasopharyngeal cancer. The purpose of this review was to evaluate the diagnostic significance of NBI in the literature and compare it to the conventional white light endoscopy. The use of narrow band imaging (NBI) and further technological achievements concerning the resolution and magnification of endoscopic images have in the past 15 years. With the use of NBI, superficial mucosal lesions, which may be missed by standard WLI endoscopy, can be identified easily by their neoangiogenic pattern. Objective:?To assess diagnostic value of the narrow band imaging and white light endoscopy in nasopharyngeal carcinoma and compare diagnostic values (sensitivity, specificity, positive predictive value and negative predictive value) with white light endoscopy. Search Methods: From 2010 to 2020, data was searched from electronic databases such as PubMed, web of science. We used narrow band imaging as a key word accordance with diagnostic modalities such as sensitivity, specificity, PPV and NPV and data were collected. Results: We have found mainly 6 studies have discussed about diagnostic value of endoscopy in nasopharyngeal carcinoma in the total of 2746 suspected patients. Among them, 5 studies have compared diagnostic values such as sensitivity, specificity, positive predictive value and negative predictive value between NBI and WLE. Among 5 studies, 4 studies have found higher sensitivity in NBI, 2 studies found higher 1 equal to WLE specificity in NBI. 3 studies have compared PPV and NPV between NBI and WLE. Among them, all the studies found higher PPV and NPV in NBI than WLE. Conclusion: Recently?developed narrow band imaging has a great significance in the diagnosis of nasopharyngeal carcinoma. Although NBI has also encountered some problem such as contact bleeding and darker image. So, further evaluation should be done.

TREATMENT OF ISCHEMIC NECROSIS OF FEMORAL HEAD BY THE FREE TRANSFERRING FIBULAR BONE GRAFT WITH VASCULAR PEDICLE IN ADULTS: A REPORT ON 95 CASES

cases (97 hips) with avascular necrosis of femoral head caused by variors factors treated by the free transferring fibular graft with vascular pedicle in the Second Teaching Hospital of Xi'an Medical University are reported. All patients have ben followed up for 2 to 11 years. Excellent and good rate of operative results was 86. 6%. A long observation indicated that this procedure was superior to the other operations for the osteonecrosis of femoral head. Successful interim and final operative results can warrant its continued use in management of this kind of patients.

Primary Cutaneous Apocrine Carcinoma of the Neck Involving the Parotid Gland: A Case Report and Review of the Literature

Introduction: Primary cutaneous apocrine carcinoma (PCAC) is a rare skin malignant tumor that originates from areas with a high concentration of apocrine glands. The incidence of PCAC in the neck is relatively low. The age of onset in PCAC ranges from 5 to 70 years old. Clinically, PCAC typically shows up as painless nodules or lumps. In immunohistochemistry, positive expression of CK-7, GCDFP-15, AR, and myoepithelial markers are helpful in the diagnosis of PCAC. This case report pertains to a 59-year-old male of Asian descent. Five years ago, a painless mass was discovered behind his right ear, which grew slowly. This patient was identified as PCAC based on clinical symptoms, pathology, immunohistochemistry, and imaging characteristics. PCAC involved the parotid gland in this case;it is easy to be misdiagnosed as a primary malignant tumor of the parotid gland on imaging. Furthermore, a thorough set of clinical, imaging, pathological, and immunohistochemical examinations must be performed to make a diagnosis because it is challenging to differentiate PCAC from metastatic breast carcinoma. Conclusion: A well-developed multidisciplinary examination is essential because PCAC can be challenging to diagnose and differentiate.

Malignant proliferative ependymoma of the neck with lymph node metastasis:A case report

BACKGROUND Malignant proliferating trichilemmal tumor(MPTT)is an infrequent malignant neoplasm originating from cutaneous appendages,with only a handful of documented cases.This report delineates a unique instance of MPTT situated in the neck,accompanied by lymph node metastasis.A comprehensive exposition of its clinical trajectory and imaging manifestation is presented,aiming to enhance comprehension and management of this atypical ailment.CASE SUMMARY Patient concerns:A 79-year-old male presented with a longstanding right neck mass persisting for over six decades,exhibiting recent enlargement over the past year.Diagnoses:Enhanced magnetic resonance imaging of the neck unveiled an elliptical mass on the right neck side,characterized by an ill-defined border and a heterogeneous signal pattern.The mass exhibited subdued signal intensity on T1-weighted imaging(T1WI)and a heterogeneous high signal on T2-weighted imaging(T2WI),interspersed with a lengthy T1 and T2 cystic signal motif.Close anatomical association with the submandibular gland joint was noted,and intravenous gadolinium diethylene triamine pentaacetic acid administration facilitated conspicuous enhancement.Substantial enhancement of the solid segment prompted an initial preoperative diagnosis of malignant nerve sheath tumor.However,post-surgery histopathological and immunohistochemical analysis conclusively confirmed the diagnosis as malignant hyperplastic external hair root sheath tumor.Intervention:Complete excision of the tumor was successfully executed.Outcomes:The patient experienced a favorable postoperative recovery.CONCLUSION Malignant proliferative trichilemmal tumor external hair root sheath tumor is a cystic-solid lesion,appearing as low signal on T1WI images or high signal on T2WI with enhancement of the solid component.Suspicions of malignancy are heightened when the tumor border is indistinct,tissue planes are breached,or when linear or patchy high signals are observed in the subcutaneous tissue on T1 liver acquisition with volume acceleration enhanced images along with intermediate signal on T2WI and restricted diffusion on diffusion-weighted imaging images.Strong consideration for malignancy should arise if there are signs of compromised adjacent tissue relationships or direct invasion evident on imaging.We have incorporated the above-mentioned content into the entire manuscript.

Targeted molecular imaging of head and neck squamous cell carcinoma:a window into precision medicine

Tumor biomarkers play important roles in tumor growth,invasion,and metastasis.Imaging of specific biomarkers will help to understand different biological activities,thereby achieving precise medicine for each head and neck squamous cell carcinoma(HNSCC)patient.Here,we describe various molecular targets and molecular imaging modalities for HNSCC imaging.An extensive search was undertaken in the PubMed database with the keywords including"HNSCC,""molecular imaging,""biomarker,"and"multimodal imaging."Imaging targets in HNSCC consist of the epidermal growth factor receptor,cluster of differentiation 44 variant 6(CD44v6),and mesenchymal-epithelial transition factor and integrins.Targeted molecular imaging modalities in HNSCC include optical imaging,ultrasound,magnetic resonance imaging,positron emission tomography,and single-photon emission computed tomography.Making the most of each single imaging method,targeted multimodal imaging has a great potential in the accurate diagnosis and therapy of HNSCC.By visualizing tumor biomarkers at cellular and molecular levels in vivo,targeted molecular imaging can be used to identify specific genetic and metabolic aberrations,thereby accelerating personalized treatment development for HNSCC patients.

The role of technetium Tc99m-tetrofosmin as head and neck tumor-seeking agent:a preliminary report

Aim:To evaluate the diagnostic value of technetium Tc99m-tetrofosmin(^(99m)Tc-TF)in primary cancers of the head and neck.Methods:Single photon emission computer tomography with planar imaging of the neck for primary site evaluation and whole body scanning for assessment of metastases in 12 patients with newly diagnosed head and neck cancer.Tumor-to-background index(T/Bg)was derived in patients with positive findings(tumor or lymph nodes).Results:The tomographic images showed increased tracer uptake in pathological sites(primary tumor or lymph node)in 9 patients(overall sensitivity 75%).Primary tumor was visualised in 7 patients(sensitivity 58%)and infiltrated lymph nodes in 4 out 7 patients(sensitivity 57%).Mean values for T/Bg index were 5.44±1.28 for primary tumor and 4.25±1.67 for lymph nodes.Mean values for T/Bg index were 4.5±0.71 for patients with in situ and grade I carcinoma and 6.68±0.36 for patients with tumor grade II and III(P=0.034,Mann-Whitney U test).Conclusion:The present study demonstrates that ^(99m)Tc-TF is a valuable radiotracer for head and neck cancer imaging.To determine the potential role of this imaging protocol in clinical practice will require a larger sample size.

Imaging-based diagnosis for extraskeletal Ewing sarcoma in pediatrics: A case report

BACKGROUND Extraskeletal Ewing sarcoma(EES)is a member of the Ewing sarcoma family of tumors which is pathologically known as a small,round,blue cell tumor involving bone and soft tissue.The prevalence of EES is only 15%-25%of all Ewing sarcoma and EES often occurs in patients aged from 20-mo-old to 30-yearsold resulting in an unfavorable prognosis.CASE SUMMARY The present case report described a 7-year-old patient with a palpable EES mass of 33 mm×27 mm×28 mm in the deep neck with symptoms of persistent dyspnea over the past 5 mo.After laboratory examinations,abnormal physiological and biochemical indicators were not found.Ultrasound images presented the mass to be complex,solid and fluid-filled with circumscribed margins and posterior acoustic enhancement.The mass also presented with partial internal vascularity.The contrast-enhanced magnetic resonance imaging scan illustrated the outstanding enhancement with fast perfusion mode in the early arterial phase. CONCLUSIONOur study suggested that a quick-growing mass in the pediatric patient is possibly a malignanttumor whether the mass has well-defined margins or not.

MultiTrans:Multi-scale feature fusion transformer with transfer learning strategy for multiple organs segmentation of head and neck CT images

Radiotherapy with precise segmentation of head and neck organs at risk(OARs)is one of the important treatment methods for head and neck cancer.In routine clinical practice,OARs are manually segmented by doctors to avoid irreversible adverse reactions caused by radiotherapy,which is time-consuming and laborious.To assist doctors in OARs segmentation,a MultiTrans framework with a multi-scale feature fusion module was proposed in this paper.In the multi-scale feature fusion module,the original image and the feature map of CNN were fused together to form a compound feature map for more complete high-resolution global information.In addition,the global information was also fully utilized in MultiTrans by using the feature map restored from the compound feature map in the skip connection.The multi-scale interactive high-resolution information can make full use of medical image information and obtain features more comprehensively,thus improve the segmentation accuracy.Experiments showed that MultiTrans had an average Dice score coefficient(DSC)of 74.01%in all organs,effectively improved segmentation accuracy.In addition,we proposed a transfer learning strategy for small organs by transferring the weight parameters of organs with a large amount of data to organs with a small amount of data to speed up the convergence of MultiTrans and reduce the demand for data volume in the MultiTrans.With this strategy,the average DSC of small organs was obviously increased,making the segmentation of small organs more accurate.The proposed framework and transfer learning strategy have the potential of assisting doctors in OARs delineation.

Clinical impact of gastrointestinal endoscopy on the early detection of pharyngeal squamous cell carcinoma: A retrospective cohort study

BACKGROUND In recent years,with the growing availability of image-enhanced gastrointestinal endoscopy,gastroenterologists have contributed to the early detection of pharyngeal squamous cell carcinomas(SCC).AIM To clarify the clinical characteristics of pharyngeal SCCs detected by gastrointestinal endoscopy.METHODS This is a retrospective cohort study conducted in a single-center,a university hospital in Japan.We retrospectively assessed the clinical records of 522 consecutive patients with oropharyngeal or hypopharyngeal SCC who were examined in our hospital between 2011 and 2018.The lesions were classified into two groups:Group GE(detected by gastrointestinal endoscopy)and Group non-GE(detected by means other than gastrointestinal endoscopy).The clinical characteristics were compared between the two groups.Continuous data were compared using the Mann–Whitney U test.Pearson’sχ2 test or Fisher's exact test was used to analyze the categorical data and compare proportions.The Kaplan–Meier method was used to estimate the cumulative patient survival rates.RESULTS In our study group,the median age was 65 years and 474 patients(90.8%)were male.One hundred and ninety-six cases(37.5%)involved the oropharynx and 326 cases(62.5%)involved the hypopharynx.Three hundred and ninety-five cases(75.7%)had some symptoms at the time of diagnosis.One hundred and forty-five(27.8%)cases had concurrent ESCC or a history of ESCC.One hundred and sixtyfour(31.4%)cases were detected by gastrointestinal endoscopy and classified as Group GE.The proportions of asymptomatic cases,cTis-1 cases and cases with no lymph node metastasis were significantly higher in Group GE than Group non-GE(61.6%vs 7.3%,P<0.001,32.9%vs 12.0%,P<0.001 and 69.5%vs 19.0%,P<0.001).Endoscopic laryngo-pharyngeal surgery or endoscopic submucosal dissection were performed in only 0.6%of the lesions in Group non-GE but in 21.3%of the lesions in Group GE(P<0.001).Overall survival was significantly longer in Group GE than in Group non-GE(P=0.018).The 2-year and 4-year survival rates were 82.5%and 70.7%in Group GE,and 71.5%and 59.0%in Group non-GE,respectively.CONCLUSION Gastrointestinal endoscopy plays an important role in the early detection and improving the prognosis of pharyngeal SCCs.

^(18)F-FDG-PET/CT-guided radiotherapy of cervical lymph nodes in head and neck squamous cell carcinoma

The use of positron emission tomography with fluor-18-fluorodeoxyglucose(FDG-PET)in clinical practice for patients with head and neck squamous cell carcinoma(HNSCC)has expanded rapidly,with implications for diagnostic staging,radiotherapy planning,adaptive radiotherapy,and post-therapy evaluation.The implementation of FDG-PET/CT in radiation treatment planning not only has consequences for target volume definition and dose prescription but is also associated with an increased overall survival in patients with HNSCC.FDG-PET/CT-guided gradient dose prescription provides a window of opportunity for treatment de-intensification of the neck in order to decrease treatment-related toxicity without compromising oncological outcome.Further,interim FDG-PET/CT during radiotherapy can be useful to assess metabolic tumor response and enables opportunities for adaptive treatment strategies.The goals are to increase treatment effectivity in poor responders and reduce unnecessary toxicity in patients with good early tumor response.Further prospective trials investigating adaptive radiotherapy based on interim PET-evaluation are needed,especially regarding human papilloma virus-negative HNSCC and patients treated with primary radiotherapy.

基于改进YOLOv5s的无人机图像识别

无人机在军事情报、航拍检测等领域能够提供目标相关的图像信息,为处理任务提供目标信息。针对无人机图像背景复杂、检测目标小、可提取特征少等问题,提出基于YOLOv5s的改进无人机图像识别算法。首先,结合CotNet模块对网络结构进行优化,提升模型自学习能力并增强识别精度;其次,对颈部网络进行改进,通过跨层链接和提高特征图分辨率更好地利用浅层特征图中包含的丰富信息来定位目标,并且在检测头部分采用解耦检测头,减少预测过程中定位与分类任务对于特征信息的冲突;最后,为了提高收敛速度和模型精度,在CIoU和EIoU损失函数的基础上对损失函数的宽高纵横比进行优化。在公开数据集VisDrone测试集上进行测试,所提算法相比原始YOLOv5s算法的mAP_(50)与mAP_(50∶95)分别提升了6.1与2.9个百分点,实验结果表明,所提模型能够有效提升无人机图像识别的准确率。

双低剂量技术在双能量头颈部CT血管成像中的应用

目的 探讨双低剂量扫描技术在双能量头颈部CTA扫描中的可行性。方法 前瞻性收集2021年1月~2021年5月间本院102名因头颈部血管疾病行头颈部CTA的患者纳入研究,随机分为CD、DLD两组,CD组行常规剂量扫描,DLD组行双低剂量扫描;分别对两组图像行MIP、VR、 MPR、 CPR、双能量去骨去钙化等后处理,用5分法对两组图像质量进行主观评价,选取颈总动脉起始部、颈内动脉起始部和大脑中动脉M1段测量血管的噪声、SNR、CNR,记录2组患者的x线剂量参数,包括CTDIvol(mGy)和DLP(mGy·cm),计算其有效剂量ED(mSv),亦计算2组患者的碘摄入量I(mg),对结果进行统计学分析。结果 CD组与DLD组的主观图像质量评分均≥3分,均能满足诊断的要求。2名医师对2组图像质量评价的一致性好(Kappa值分别为0.817、0.82 5)。2名医师对2组图像的主观质量评分的差异无统计学意义(Z=-0.572、-0.2 83,均P>0.05)。CD组与DLD组图像各层面血管CT值的差异均无统计学意义(t=-0.05、0.689、0.906,均P<0.05);颈内动脉起始部、大脑中动脉M1段层面血管噪声、SNR、CNR的差异均无统计学意义(t=-0.830~1.842,均P>0.05);颈总动脉起始部层面CD组噪声大于DLD组(t=2.855,P<0.05),SNR、CNR小于DLD组(t=-4.959、-5.041,均P<0.05)。DLD组患者C TDIvol、DLP及ED较CD组分别降低36.9%、35.3%、35.2%(t=186.138、37.753、37.753,均P<0.05)。DLD组患者碘摄入量较CD组降低57.1%(10.5g VS.245g)。结论 双低剂量双能量头颈部CTA扫描技术在不影响图像质量的前提下,降低了患者接受的辐射剂量和对比剂碘摄入量。