Magnetic resonance-guided focused ultrasound for essential tremor:a prospective,single center,single-arm study

The safety and effectiveness of magnetic resonance-guided focused ultrasound thalamotomy has been broadly established and validated for the treatment of essential tremor.In 2018,the first magnetic resonance-guided focused ultrasound system in Chinese mainland was installed at the First Medical Center of the PLA General Hospital.This prospective,single center,open-label,single-arm study was part of a worldwide prospective multicenter clinical trial(ClinicalTrials.gov Identifier:NCT03253991)conducted to confirm the safety and efficacy of magnetic resonance-guided focused ultrasound for treating essential tremor in the local population.From 2019 to 2020,10 patients with medication refractory essential tremor were recruited into this open-label,single arm study.The treatment efficacy was determined using the Clinical Rating Scale for Tremor.Safety was evaluated according to the incidence and severity of adverse events.All of the subjects underwent a unilateral thalamotomy targeting the ventral intermediate nucleus.At the baseline assessment,the estimated marginal mean of the Clinical Rating Scale for Tremor total score was 58.3±3.6,and this improved after treatment to 23.1±6.4 at a 12-month follow-up assessment.A total of 50 adverse events were recorded,and 2 were defined as serious.The most common intraoperative adverse events were nausea and headache.The most frequent postoperative adverse events were paresthesia and equilibrium disorder.Most of the adverse events were mild and usually disappeared within a few days.Our findings suggest that magnetic resonance-guided focused ultrasound for the treatment of essential tremor is effective,with a good safety profile,for patients in Chinese mainland.

Stereotactic radiotherapy and the potential role of magnetic resonance-guided adaptive techniques for pancreatic cancer

BACKGROUND Pancreatic cancer is a malignancy with one of the poorest prognoses amongst all cancers.Patients with unresectable tumours either receive palliative care or undergo various chemoradiotherapy regimens.Conventional techniques are often associated with acute gastrointestinal toxicities,as adjacent critical structures such as the duodenum ultimately limits delivered doses.Stereotactic body radiotherapy(SBRT)is an advanced radiation technique that delivers highly ablative radiation split into several fractions,with a steep dose fall-off outside target volumes.AIM To discuss the latest data on SBRT and whether there is a role for magnetic resonance-guided techniques in multimodal management of locally advanced,unresectable pancreatic cancer.METHODS We conducted a search on multiple large databases to collate the latest records on radiotherapy techniques used to treat pancreatic cancer.Out of 1229 total records retrieved from our search,36 studies were included in this review.RESULTS Studies indicate that SBRT is associated with improved clinical efficacy and toxicity profiles compared to conventional radiotherapy techniques.Further dose escalation to the tumour with SBRT is limited by the poor soft-tissue visualisation of computed tomography imaging during radiation planning and treatment delivery.Magnetic resonance-guided techniques have been introduced to improve imaging quality,enabling treatment plan adaptation and re-optimisation before delivering each fraction.CONCLUSION Therefore,SBRT may lead to improved survival outcomes and safer toxicity profiles compared to conventional techniques,and the addition of magnetic resonance-guided techniques potentially allows dose escalation and conversion of unresectable tumours to operable cases.

Magnetic resonance imaging findings of radiation-induced breast angiosarcoma:A case report

BACKGROUND Breast conservation surgery(BCS)with adjuvant radiotherapy has become a gold standard in the treatment of early-stage breast cancer,significantly reducing the risk of tumor recurrence.However,this treatment is associated with adverse effects,including the rare but aggressive radiation-induced angiosarcoma(RIAS).Despite its rarity and nonspecific initial presentation,RIAS presents a challenging diagnosis,emphasizing the importance of imaging techniques for early detection and accurate diagnosis.CASE SUMMARY We present a case of a 48-year-old post-menopausal woman who developed skin ecchymosis on the right breast seven years after receiving BCS and adjuvant radiotherapy for breast cancer.Initial mammography and ultrasound were inconclusive,showing post-treatment changes but failing to identify the underlying angiosarcoma.Contrast-enhanced breast magnetic resonance imaging(MRI)revealed diffuse skin thickening and nodularity with distinctive enhan-cement kinetics,leading to the diagnosis of RIAS.This case highlights the crucial role of MRI in diagnosing and determining the extent of RIAS,facilitating timely and appropriate surgical intervention.CONCLUSION Breast MRI is crucial for detecting RIAS,especially when mammography and ultrasound are inconclusive.

Renal ablation using magnetic resonance-guided high intensity focused ultrasound: Magnetic resonance imaging and histopathology assessment

AIM: To use magnetic resonance-guided high intensity focused ultrasound(MRg-HIFU), magnetic resonance imaging(MRI) and histopathology for noninvasively ablating, quantifying and characterizing ablated renal tissue. METHODS: Six anesthetized/mechanically-ventilated pigs underwent single/double renal sonication(n = 24) using a 3T-MRg-HIFU(1.1 MHz frequency and 3000J-4400 J energies). T2-weighted fast spin echo(T2-W), perfusion saturation recovery gradient echo and contrast enhanced(CE) T1-weighted(T1-W) sequences were used for treatment planning, temperature monitoring, lesion visualization, characterization and quantification, respectively. Histopathology was conducted in excised kidneys to quantify and characterize cellular and vascular changes. Paired Student's t-test was used and a P-value < 0.05 was considered statistically significant.RESULTS: Ablated renal parenchyma could not be differentiated from normal parenchyma on T2-W or nonCE T1-W sequences. Ablated renal lesions were visible as hypoenhanced regions on perfusion and CE T1-W MRI sequences, suggesting perfusion deficits and necrosis. Volumes of ablated parenchyma on CE T1-W images invivo(0.12-0.36 cm3 for single sonication 3000 J, 0.50-0.84 cm3, for double 3000 J, 0.75-0.78 cm3 for single 4400 J and 0.12-2.65 cm3 for double 4400J) and at postmortem(0.23-0.52 cm3, 0.25-0.82 cm3, 0.45-0.68 cm3 and 0.29-1.80 cm3, respectively) were comparable. The ablated volumes on 3000 J and 4400 J double sonication were significantly larger than single(P < 0.01), thus, the volume and depth of ablated tissue depends on the applied energy and number of sonication. Macroscopic and microscopic examinations confirmed the locations and presence of coagulation necrosis, vascular damage and interstitial hemorrhage, respectively.CONCLUSION: Contrast enhanced MRI provides assessment of MRg-HIFU renal ablation. Histopathology demonstrated coagulation necrosis, vascular damage and confirmed the volume of damage seen on MRI.

Magnetic resonance imaging for prostate cancer before radical and salvage radiotherapy: What radiation oncologists need to know

External beam radiotherapy(EBRT) is one of the principal curative treatments for patients with prostate cancer(PCa). Risk group classification is based on prostate-specific antigen(PSA) level, Gleason score, and T-stage. After risk group determination, the treatment volume and dose are defined and androgen deprivation therapy is prescribed, if appropriate. Traditionally, imaging has played only a minor role in T-staging due to the low diagnostic accuracy of conventional imaging strategies such as transrectal ultrasound, computed tomography, and morphologic magnetic resonance imaging(MRI). As a result, a notable percentage of tumours are understaged, leading to inappropriate and imprecise EBRT. The development of multiparametric MRI(mp MRI), an imaging technique that combines morphologic studies with functional diffusion-weighted sequences and dynamic contrastenhanced imaging, has revolutionized the diagnosis and management of PCa. As a result, mpM RI is now used in staging PCa prior to EBRT, with possible implications for both risk group classification and treatment decisionmaking for EBRT. mpM RI is also being used in salvageradiotherapy(SRT), the treatment of choice for patients who develop biochemical recurrence after radical prostatectomy. In the clinical context of biochemical relapse, it is essential to accurately determine the site of recurrence-pelvic(local, nodal, or bone) or distant-in order to select the optimal therapeutic management approach. Studies have demonstrated the value of mpM RI in detecting local recurrences-even in patients with low PSA levels(0.3-0.5 ng/m L)-and in diagnosing bone and nodal metastasis. The main objective of this review is to update the role of mpM RI prior to radical EBRT or SRT. We also consider future directions for the use and development of MRI in the field of radiation oncology.

Metabonomic studies of pancreatic cancer response to radiotherapy in a mouse xenograft model using magnetic resonance spectroscopy and principal components analysis

AIM: To investigate the metabolic profiles of xenograft pancreatic cancer before and after radiotherapy by high-resolution magic angle spinning proton magnetic resonance spectroscopy (HRMAS 1H NMR) combined with principal components analysis (PCA) and evaluate the radiotherapeutic effect. METHODS: The nude mouse xenograft model of human pancreatic cancer was established by injecting human pancreatic cancer cell SW1990 subcutaneously into the nude mice. When the tumors volume reached 800 mm3 , the mice received various radiation doses. Two weeks later, tumor tissue sections were prepared for running the NMR measurements. 1H NMR and PCA were used to determine the changes in the metabolic profiles of tumor tissues after radiotherapy. Metabolic profiles of normal pancreas, pancreatic tumor tissues, and radiationtreated pancreatic tumor tissues were compared. RESULTS: Compared with 1H NMR spectra of the normal nude mouse pancreas, the levels of choline, taurine, alanine, isoleucine, leucine, valine, lactate, and glutamic acid of the pancreatic cancer group were increased, whereas an opposite trend for phosphocholine, glycerophosphocholine, and betaine was observed. The ratio of phosphocholine to creatine, and glycerophosphocholine to creatine showed noticeable decrease in the pancreatic cancer group. After further evaluation of the tissue metabolic profile after treatment with three different radiation doses, no significant change in metabolites was observed in the 1H NMR spectra, while the inhibition of tumor growth was in proportion to the radiation doses. However, PCA results showed that the levels of choline and betaine were decreased with the increased radiation dose, and conversely, the level of acetic acid was dramatically increased. CONCLUSION: The combined methods were demonstrated to have the potential for allowing early diagnosis and assessment of pancreatic cancer response to radiotherapy.

The Value of Magnetic Resonance Diffusion-Weighted Imaging in Evaluating the Efficacy of Concurrent Chemoradiotherapy in Patients with Hypopharyngeal Carcinoma

Objective: To investigate the application value of magnetic resonance diffusion-weighted imaging (DWI) combined with conventional magnetic resonance imaging (MRI) in evaluating the efficacy of concurrent chemoradiotherapy for hypopharyngeal carcinoma. Methods: A total of 20 patients with hypopharyngeal carcinoma diagnosed by pathological biopsy (who only received chemoradiotherapy without surgery) were collected. Before treatment, all patients underwent conventional MRI and DWI scanning, MRI characteristics of patients were analyzed, and maximum cross-sectional area of the tumor and average apparent diffusion coefficient (ADC) value were measured. One month after treatment, MRI was performed again to measure residual tumor area and ADC value, and the tumor remission rate was calculated. The changes in tumor ADC values before and after treatment were analyzed and their correlation with tumor remission rate was analyzed. The differences in ADC values and changes between complete response patients (CR group) and incomplete response patients (non-CR group) before and after treatment were analyzed. Results: The tumor area of 20 patients with hypopharyngeal cancer was 3.48 (0.93 - 5.6) cm2 before treatment and 0.24 (0 - 0.9) cm2 after treatment. There were 15 patients (15/20, 75%) in the CR group and 5 patients (5/20, 25.0%) in the non-CR group. The remission rate was 90.3% (6.0% - 100%). The average ADC value of the tumor before treatment was negatively correlated with the tumor remission rate after treatment (r = ?0.786, ?0.813, P Conclusion: The ADC value of tumor before treatment and the change of ADC value of tumor before and after treatment have a certain significance in evaluating the early remission rate of hypopharyngeal carcinoma after chemoradiotherapy.

Three-Tesla Magnetic Resonance and Computed Tomography Imaging in Three-Dimensional Conformal Radiotherapy for Localized Prostate Cancer

Aims and background: we evaluate CT-3Tesla MRI fusion in conformal radiotherapy for localized prostate cancer.Methods: 18 consecutive patients underwent a 3T MRI scan under radiotherapy planning conditions, after the CT scan. Bowel and bladder preparation were prescribed. CT and MR images were automatically fused;prostate and seminal vesicles were contoured on CT and on MRI, organs at risk were defined on CT-MRI fusion. Late rectal and sexual toxicity, differences in target volume between MRI and CT and differences in rectal and penile bulb dose distribution based on CT only or on CT-MRI fusion were evaluated.Results: one patient experienced a late rectal toxicity;no patient had sexual toxicity. The difference between the mean MRI and CT target volumes was statistically significant (p = 0.0001 paired Student's t-test). The dose-volume histogram (DVH) analysis shows a significant reduction of the dose received by the rectum and the penile bulb in MRI-plans compared to CT-plans.Conclusions: 3 Tesla MRI scan under radiotherapy planning conditions along with bowel preparation significantly improves the definition of the target volume sparing normal tissue irradiation.

Role of dynamic perfusion magnetic resonance imaging in patients with local advanced rectal cancer

BACKGROUND The management of rectal cancer patients is mainly based on the use of the magnetic resonance imaging(MRI)technique as a diagnostic tool for both staging and restaging.After treatment,to date,the evaluation of complete response is based on the histopathology assessment by using different tumor regression grade(TRG)features(e.g.,Dworak or Mandard classifications).While from the radiological point of view,the main attention for the prediction of a complete response after chemotherapy treatment focuses on MRI and the potential role of diffusion-weighted images and perfusion imaging represented by dynamiccontrast enhanced MRI.The main aim is to find a reliable tool to predict tumor response in comparison to histopathologic findings.AIM To investigate the value of dynamic contrast-enhanced perfusion-MRI parameters in the evaluation of the healthy rectal wall and tumor response to chemo-radiation therapy in patients with local advanced rectal cancer with histopathologic correlation.METHODS Twenty-eight patients with biopsy-proven rectal adenocarcinoma who underwent a dynamic contrast-enhanced MR study performed on a 1.5 T MRI system(Achieva,Philips),before(MR1)and after chemoradiation therapy(MR2),were enrolled in this study.The protocol included T1 gadolinium enhanced THRIVE sequences acquired on axial planes.A dedicated workstation was used to generate color permeability maps.Region of interest was manually drawn on tumor tissue and normal rectal wall,hence the following parameters were calculated and statistically analyzed:Relative arterial enhancement(RAE),relative venous enhancement(RVE),relative late enhancement(RLE),maximum enhancement(ME),time to peak and area under the curve(AUC).Perfusion parameters were related to pathologic TRG(Mandard’s criteria;TRG1=complete regression,TRG5=no regression).RESULTS Ten tumors(36%)showed complete or subtotal regression(TRG1-2)at histology and classified as responders;18 tumors(64%)were classified as non-responders(TRG3-5).Perfusion MRI parameters were significantly higher in the tumor tissue than in the healthy tissue in MR1(P<0.05).At baseline(MR1),no significant difference in perfusion parameters was found between responders and nonresponders.After chemo-radiation therapy,at MR2,responders showed significantly(P<0.05)lower perfusion values[RAE(%)54±20;RVE(%)73±24;RLE(%):82±29;ME(%):904±429]compared to non-responders[RAE(%):129±45;RVE(%):154±39;RLE(%):164±35;ME(%):1714±427].Moreover,in responders group perfusion values decreased significantly at MR2[RAE(%):54±20;RVE(%):73±24;RLE(%):82±29;ME(%):904±429]compared to the corresponding perfusion values at MR1[RAE(%):115±21;RVE(%):119±21;RLE(%):111±74;ME(%):1060±325];(P<0.05).Concerning the time-intensity curves,the AUC at MR2 showed significant difference(P=0.03)between responders and non-responders[AUC(mm2×10-3)121±50 vs 258±86],with lower AUC values of the tumor tissue in responders compared to nonresponders.In non-responders,there were no significant differences between perfusion values at MR1 and MR2.CONCLUSION Dynamic contrast perfusion-MRI analysis represents a complementary diagnostic tool for identifying vascularity characteristics of tumor tissue in local advanced rectal cancer,useful in the assessment of treatment response.

Diffusion-weighted magnetic resonance imaging in management of bladder cancer, particularly with multimodal bladder-sparing strategy

Bladder-sparing strategy for muscle-invasive bladdercancer(MIBC) is increasingly demanded instead ofradical cystectomy plus urinary diversion. Multimodaltherapeutic approaches consisting of transurethralresection, chemotherapy, radiotherapy and/or partialcystectomy improve patients' quality of life by preserv-ing their native bladder and sexual function withoutcompromising oncological outcomes. Because a favor-able response to chemoradiotherapy(CRT) is a prereq-uisite for successful bladder preservation, predictingand monitoring therapeutic response is an essentialpart of this approach. Diffusion-weighted magneticresonance imaging(DW-MRI) is a functional imagingtechnique increasingly applied to various types of can-cers. Contrast in this imaging technique derives fromdifferences in the motion of water molecules among tissues and this information is useful in assessing the biological behavior of cancers. Promising results in pre-dicting and monitoring the response to CRT have been reported in several types of cancers. Recently, growing evidence has emerged showing that DW-MRI can serve as an imaging biomarker in the management of blad-der cancer. The qualitative analysis of DW-MRI can be applied to detecting cancerous lesion and monitoring the response to CRT. Furthermore, the potential role of quantitative analysis by evaluating apparent diffu-sion coefficient values has been shown in character-izing bladder cancer for biological aggressiveness and sensitivity to CRT. DW-MRI is a potentially useful tool for the management of bladder cancer, particularly in multimodal bladder-sparing approaches for MIBC.

Current applications for magnetic resonance-guided focused ultrasound in the treatment of Parkinson’s disease

Magnetic resonance-guided focused ultrasound(MRgFUS)is a novel and minimally invasive technology.Since the US Food and Drug Administration approved unilateral ventral intermediate nucleus-MRgFUS for medication-refractory essential tremor in 2016,studies on new indications,such as Parkinson’s disease(PD),psychiatric diseases,and brain tumors,have been on the rise,and MRgFUS has become a promising method to treat such neurological diseases.Currently,as the second most common degenerative disease,PD is a research hotspot in the field of MRgFUS.The actions of MRgFUS on the brain range from thermoablation,blood-brain barrier(BBB)opening,to neuromodulation.Intensity is a key determinant of ultrasound actions.Generally,high intensity can be used to precisely thermoablate brain targets,whereas low intensity can be used as molecular therapies to modulate neuronal activity and open the BBB in conjunction with injected microbubbles.Here,we aimed to summarize advances in the application of MRgFUS for the treatment of PD,with a focus on thermal ablation,BBB opening,and neuromodulation,in the hope of informing clinicians of current applications.

心血管磁共振成像评估肿瘤治疗相关心血管损伤的应用进展

随着肿瘤治疗技术的发展,肿瘤患者的生存率得到大幅改善。但肿瘤治疗可能伴有潜在的心血管毒性作用,导致心血管疾病的发病率和死亡率增加,最终肿瘤患者可能并非死于肿瘤,而死于肿瘤治疗,早期识别心血管损伤并制订相关策略改善这种副作用至关重要。心血管磁共振成像可实现对心脏结构、心脏功能、心肌组织特征及心脏大血管血流动力学的“一站式”评价,在评价心血管损伤,尤其是早期损伤方面具有重要作用。本综述回顾各种心血管磁共振成像方法在评估肿瘤治疗相关心血管损伤中的应用和进展。

MRI检查鼻咽癌放射性颞叶损伤的漏诊原因

目的:放射治疗是鼻咽癌的主要治疗方法,但容易发生放射性颞叶损伤(radiotherapy-induced temporal lobe injury,RTLI)。磁共振成像(magnetic resonance imaging,MRI)检查是鼻咽癌放射治疗后RTLI的主要诊断方法,但容易漏诊。本研究旨在探讨MRI检查鼻咽癌放射治疗后RTLI漏诊的原因。方法:回顾性分析2010年1月至2021年4月在中南大学湘雅医院诊断为鼻咽癌且接受放射治疗患者的临床和MRI资料。由2位放射科医生重新审阅患者放射治疗前、后所有头颈部(包括鼻咽部和颅脑)MRI资料,对首次发现颞叶晚迟发反应型放射性脑损伤的患者作出首次RTLI诊断。若首次诊断鼻咽癌RTLI患者的原始诊断未报告颞叶病变,则定义为漏诊。将首次诊断鼻咽癌RTLI患者分为漏诊组和非漏诊组。比较漏诊组与非漏诊组的一般临床资料和影像学资料,并进一步采用多因素Logistic回归分析MRI漏诊首次RTLI的独立危险因素。结果:共纳入符合要求的鼻咽癌放射治疗后首次诊断为RTLI的患者187例,原始诊断报告漏诊120例,未漏诊67例,首次诊断RTLI的准确率为35.8%,漏诊率为64.2%。漏诊组与未漏诊组在病灶大小、病灶是否仅在内侧颞叶、对侧颞叶有无病灶、有无白质高信号/囊变及出血、MRI检查部位以及有无水抑制反转恢复序列(fluid attenuated inversion recovery,FLAIR)序列方面的差异均有统计学意义(均P<0.05)。多因素Logistic回归分析显示:病灶≤25 mm、病灶无强化、病灶无囊变及出血、病灶仅在内侧颞叶和仅检查鼻咽部MRI是MRI漏诊首次RTLI的独立危险因素(均P<0.05)。结论:MRI首次诊断RTLI的漏诊主要与病灶的大小和部位、病灶的影像学特点及MRI检查部位相关。

多参数MRI纹理分析预测直肠癌患者放射治疗后早期股骨头坏死

目的 探讨多参数MRI(mpMRI)纹理分析预测直肠癌患者放射治疗(放疗)后早期股骨头坏死(FHN)的价值。方法 回顾性分析52例接受盆腔放疗直肠癌患者放疗前2周及放疗后3个月内的盆腔MRI,其中31例未见FHN,21例出现早期FHN(Ⅰ期16例,Ⅱ期5例)。采用3D-slicer软件基于T1WI、T2WI和弥散加权成像(DWI)分割右侧股骨头,并提取其纹理参数;对比放疗前后纹理参数,将差异有统计学意义的放疗前参数纳入多因素logistic回归分析,建立模型T1WI、模型T2WI、模型DWI及模型T1WI+T2WI+DWI。根据放疗后影像学所见行股骨头坏死骨循环研究协会(ARCO)分期,以受试者工作特征(ROC)曲线分析单一纹理参数及联合模型预测直肠癌患者放疗后早期FHN的效能。结果 T1WI及T2WI纹理参数中,放疗前股骨头能量及均匀性高于放疗后;DWI纹理参数中,放疗前股骨头能量高于、而长行程高灰度强调及短行程高灰度强调低于放疗后。上述放疗前纹理参数单一预测直肠癌患者放疗后早期FHN的曲线下面积(AUC)为0.581~0.712,模型T1WI、模型T2WI、模型DWI和模型T1WI+T2WI+DWI的AUC分别为0.660、0.713、0.770和0.853。结论 mpMRI纹理分析可有效预测直肠癌患者放疗后早期FHN。

对比自旋回波与平面回波弥散张量成像显示颞叶放射性脑病

目的对比自旋回波(TSE)弥散张量成像(DTI)与平面回波(EPI)DTI显示颞叶放射性脑病(REP)图像质量。方法前瞻性纳入30例疑REP进展的放射治疗后鼻咽癌患者,以5分制对TSE-DTI和EPI-DTI图像清晰度、磁化率伪影及变形程度进行主观评分,并对其平均弥散系数(MD)、各向异性分数(FA)、信噪比(SNR)、对比度噪声比(CNR)及失真率(DR)差异进行客观评价。结果TSE-DTI磁化率伪影及变形评分均高于EPI-DTI(P均<0.001)。REP边缘及正常脑组织FA均低于、SNR和CNR均高于EPI-DTI(P均<0.001),而REP病灶及双侧颞叶DR均低于EPI-DTI(P均<0.001)。结论相比EPI-DTI,TSE-DTI可通过减少图像磁化率伪影和变形而显著提高图像显示REP质量。

基于核磁共振和鳞状细胞癌抗原预测早期宫颈鳞癌辅助放疗的模型

目的建立一个基于核磁共振和鳞状细胞癌抗原(SCCA)模型,预测早期宫颈鳞癌是否需要术后辅助放疗。方法收集2018—2021年医院收治的67例早期宫颈鳞癌(ⅠB1、ⅠB2、ⅡA1)患者的临床资料,回顾性分析病灶大小、浸润深度、组织分化程度、年龄、SCCA、表观弥散系数(ADC)值、人乳头瘤病毒(HPV)亚型与术后辅助放疗的关系。通过单因素及多因素分析,筛选出影响术后辅助放疗的独立危险因素。应用受试者工作特征(ROC)曲线求得独立危险因素的截断值,进一步构建预测模型。结果单因素分析后发现,病灶大小(P<0.001)、浸润深度(P=0.001)、组织分化程度(P=0.002)、SCCA(P<0.001)、ADC值(P<0.001)影响术后辅助放疗,二元logistic回归多因素分析后发现,病灶大小(OR=1.201,P=0.021)、SCCA(OR=1.608,P=0.033)、ADC值(OR=0.013,P=0.043)是影响辅助放疗的独立危险因素。利用ROC求得截断值分别为:SCCA=4.84μg·L^(-1),病灶=27 mm,ADC=0.907×10^(-3)mm^(2)·s^(-1)。当同时满足任意2个指标时,术后辅助放疗的比率达94.7%以上。结论肿瘤≥27 mm、ADC值≤0.907×10^(-3)mm^(2)·s^(-1)、SCCA≥4.84μg·L^(-1)可以作为判断辅助放疗的指标,若同时满足任意2个指标,辅助放疗的可能性明显增加,此时应慎重考虑治疗方式,尽量避免根治性手术及辅助放疗双重治疗模式带来的严重并发症的发生。

Neoadjuvant treatment of rectal cancer: Where we are and where we are going

Locally advanced rectal cancer requires a multidisciplinary approach based on total neoadjuvant treatment with radiotherapy(RT)and chemotherapy(ChT),followed by deferred surgery.Currently,alternatives to the standard total neoadjuvant therapy(TNT)are being explored,such as new ChT regimens or the introduction of immunotherapy.With standard TNT,up to a third of patients may achieve a complete pathological response(CPR),potentially avoiding surgery.However,as of now,we lack predictive markers of response that would allow us to define criteria for a conservative organ strategy.The presence of muta-tions,genes,or new imaging tests is helping to define these criteria.An example of this is the diffusion coefficient in the diffusion-weighted sequence of magnetic resonance imaging and the integration of this imaging technique into RT treatment.This allows for the monitoring of the evolution of this coefficient over successive RT sessions,helping to determine which patients will achieve CPR or those who may require intensification of neoadjuvant therapy.

磁共振引导放疗成像几何精度测试

目的:评估成像系统多因素尤其是图像几何精度对靶区和危及器官勾画的影响。方法:使用模体测试1.5T磁共振直线加速器系统的成像性能,包括磁共振图像几何失真评估以及由图像几何失真等因素引起的勾画偏差评估。使用Model 604-GS大场磁共振图像失真模体对磁共振引导放疗流程的磁共振图像进行几何失真度测试;同时使用CIRS Model008z上腹部模体进行相关靶区及OAR的勾画差异分析。结果:几何失真度结果显示,3DT1WI-FFE图像平均几何失真度0.54 mm,最大失真度1.96 mm;3DT2WI-TSE图像平均几何失真度0.53 mm,最大失真度1.68 mm,其中较大失真度的控制点分布于模体边缘,符合既往报道的磁共振图像特性。基于CT的勾画与基于3DT1WI-FFE和3DT2WI-TSE图像的勾画平均结果分别为MDA=1.17 mm,DSC=0.91;MDA=0.86 mm,DSC=0.94。结论:本研究定量评估了磁共振引导放疗成像系统的几何精度。基于仿真模拟人的勾画分析表明相对于CT图像,基于磁共振图像的勾画差异符合临床要求,同时3DT2WI-TSE图像在勾画精度相比于3DT1WI-FFE图像更有优势。

CT与MRI结合评估脑胶质瘤分级的价值及指导放化疗的作用探究

目的分析CT与磁共振成像(MRI)结合评估脑胶质瘤分级的价值,并探究其指导放化疗的作用。方法选择2020年5月至2022年5月医院收治的86例脑胶质瘤患者,所有患者入院时均接受CT及MRI检查,以组织病理检查为基准,分析CT与MRI单独及联合评估脑胶质瘤分级与组织病理检查结果的一致性。结果经组织病理检查结果显示,86例脑胶质瘤患者中脑胶质瘤Ⅰ级9例(10.47%),Ⅱ级29例(33.72%),Ⅲ级21例(24.42%),Ⅳ级27例(31.40%);CT、MRI单独评估脑胶质瘤分级结果与组织病理检查结果一致性理想(Kappa=0.709、0.743,P<0.05);CT与MRI联合评估脑胶质瘤分级结果与组织病理检查结果一致性极好(Kappa=0.823,P<0.05);CT-MRI融合图像组GTV、临床靶区、计划靶区体积小于CT图像组(P<0.05);CT-MRI融合图像组靶区受照最大剂量、平均剂量低于CT图像组(P<0.05);CT-MRI融合图像组脑干、视神经、视交叉、垂体、晶体、眼球最大受照剂量及最小受照剂量均低于CT图像组(P<0.05);随访1年,CT图像组复发率(32.56%)与CT-MRI融合图像组复发率(37.21%)比较,差异不显著(P>0.05)。结论CT与MRI结合评估脑胶质瘤分级与组织病理检查一致性极好,具有较高临床应用价值,且在放化疗指导中具有重要作用,能够降低正常组织放疗照射剂量,保护正常组织。

利用基于图像配准的深度学习方法提高磁共振引导前列腺癌放疗自动勾画精度

目的:改进在线磁共振图像中前列腺靶区和危及器官的自动勾画性能,提高磁共振引导前列腺癌在线自适应放射治疗的效率。方法:对40例接受磁共振引导在线自适应放射治疗的前列腺癌患者进行回顾性研究,其中训练集25例、验证集5例、测试集10例。将模拟定位图像与相应勾画信息和在线磁共振图像进行配准后输入深度学习网络,实现对磁共振图像的自动勾画,并与形变配准方法和单MR输入的深度学习方法进行比较。结果:本文方法的自动勾画准确性整体优于形变配准方法和单MR输入的深度学习方法,临床靶区、膀胱、直肠和左、右侧股骨头的平均Dice相似性指数分别达0.896、0.941、0.840、0.943和0.940。结论:本文方法能有效提高磁共振引导前列腺癌在线自适应放射治疗中自动勾画的准确性和效率。