中枢神经系统肿瘤的MRI影像标注专家共识

随着人工智能（AI）技术在医学影像领域广泛应用,数据的标准化是关键。医学影像数据的标注是其中的重要环节,标注的质量直接决定了AI模型的效能。目前AI技术已经用于中枢神经系统肿瘤性疾病的多方面研究。为了规范中枢神经系统肿瘤数据的标注,中国医师协会放射医师分会“互联网+”医学影像专委会联合业内影像医学、计算机科学和人工智能科技企业的专家结合实践操作并反复讨论,对中枢神经系统肿瘤的MRI影像标注提出初步指导意见,旨在统一数据采集及标注规则,从而提高模型的泛化性,促进AI技术的优化、验证及推广。     

MSCT容积再现在并腿畸形尸检中的应用

目的：探讨胎儿并腿畸形的骨骼异常及尸检胎儿 MSCT容积再现对产前B超的提示作用。方法：对8例疑似并腿畸形胎儿行 MRI检查,引产后行 MSCT检查。结果：8例并腿畸形胎儿中,7例为单胎,1例为臀部联体双胎之一。8例中,1例表现为单个下肢,7例为形式各异的下肢融合畸形。8例均有髂骨异常、尾椎部分或全部缺失。7例伴有各种各样的胸腰椎和肋骨畸形,2例并左上肢畸形融合。结论：MSCT容积再现可以提供胎儿详细立体的影像学资料,提高对并腿畸形骨骼异常的认识及产前诊断水平。     

MSCT容积再现技术对小肠病变的临床应用价值

目的:探讨MSCT容积再现技术(volume rendering technique VRT)的成像方法,并评价其在小肠病变的临床应用方法和价值.方法:收集我院2006年4月至2007年3月经手术或病理证实的小肠病变81例病例,对其MSCT平扫及双期增强资料进行回顾性容积再现技术处理并与其它后处理技术进行对照,比较它们的CT影像特征.结果:几种后处理方法各有特点,容积再现技术能准确、立体地显示小肠病变的具体病灶及与其供血动脉之间的关系,结合薄层轴位图像及其它后处理方法能明确病灶的部位、范围和程度.结论:容积再现技术为临床提供详细、立体的影像学资料,对明确小肠病变的诊断,制定手术方案和提高手术安全性具有重要的临床价值.     

Low-contrast detectability in volume rendering: a phantom study on multidector-row spiral CT data

To cope with the increasing amount of CT data, there is growing interest in direct volume-rendering techniques (VRT) as a diagnostic tool. The aim of this phantom study was to analyze the low-contrast detectability (LCD) of VRT compared with multi-planar reformations (MPR). Soft tissue lesions were simulated by spheres of different diameters (3–8 mm). The average lesion density was 15 HU compared with a background density of 35 HU. Two different CT protocols with 40 and 150 mAs were performed on a multi-detector row CT. The scanning parameters were as following: 140 kV; 2×0.5-mm slice collimation; pitch 2 (table movement per rotation/single slice collimation), and reconstruction with 0.5-mm slice thickness at 0.5-mm interval. A B30 kernel was used for reconstruction. The VRT was performed by mapping Hounsfield values to gray levels equal to a CT window (center: 60 HU; window: 370 HU ). A linear ramp was applied for the opacity transfer function varying the maximum opacity between 0.1 and 1.0. A statistical method based on the Rose model was used to calculate the detection threshold depending on lesion size and image noise. Additionally, clinical data of 2 patients with three liver lesions of different sizes and density were evaluated. In VRT, LCD was most dependent on object size. Regarding lesions larger than 5 mm, VRT is significantly superior to MPR (p<0.05) for all opacity settings. In lesions sized 3–5 mm a maximum opacity level approximately 40–50% showed a near equivalent detectability in VRT and MPR. For higher opacity levels VRT was superior to MPR. Only for 3-mm lesions MPR performed slightly better in low-contrast detectability (p<0.05). Compared with MPR, VRT shows similar performance in LCD. Due to noise suppression effects, it is suited for visualization of data with high noise content.     

容积重建术和表面成像术在椎动脉CT血管造影中的应用

目的：探讨容积重建术（VR）和表面成像术（SSD）在椎动脉CT血管（CTA）成像中的应用价值。方法：对65例临床疑诊为椎动脉椎病患者作椎动脉CTA检查，采用VR和SSD两种方法重建图像，VR通过容积漫游，SSD通过设置双阈值来显示椎动脉。结果：65例，130例血管显示129例，1支全程闭塞不显示，发现先天变异31支；血管因骨质增生受压移位17处，血管狭窄21例；颅内段血管呈串珠状45处；钙化3处，讨论：VR能清晰显示椎示椎动脉全貌和伴行骨骼的解剖关系，大大提高椎动脉病变的检出阳性率。SSD优良图像仅占50％左右，约半数的病人椎动脉显示不满意，实用价值有待进一步研究。     

320排动态容积CT在评价冠状动脉解剖结构方面的价值

目的:探讨320排动态容积CT在评价冠状动脉解剖结构方面的价值,阐述其在CTA扫描方面的优势,并分析其对冠状动脉造影(coronary angiography,CAG)及介入治疗(percutaneous coronary intervention,PCI)的临床指导意义。方法:行320排动态容积扫描的冠状动脉CTA受检者中CTA图像未发现病变且图像质量为1级者70例,均测量其左冠状动脉主干、右冠状动脉、左前降支及左回旋支开口处的内径,左、右冠状动脉的开口位置、开口角度,左前降支与左回旋支之间角度及左主干长度,并按性别分组,行统计学分析。结果:1左冠状动脉主干、右冠状动脉、左前降支及左回旋支开口处的内径平均值分别为(4.10±0.80)mm、(3.52±0.69)mm、(3.43±0.72)mm及(2.84±0.77)mm。其中,男性平均值分别为(4.25±0.80)mm、(3.78±0.68)mm、(3.54±0.75)mm及(3.06±0.83)mm;女性平均值分别为(3.91±0.79)mm、(3.18±0.53)mm、(3.30±0.66)mm及(2.54±0.58)mm。2左、右冠状动脉起始处与升主动脉之间夹角分别为110.13°±15.04°、47.49°±17.19°。其中,男性平均值分别为108.42°±17.25°、45.57°±17.07°;女性平均值分别为112.41°±11.33°、50.05°±17.30°。左前降支与左回旋支之间夹角平均为72.70±30.88°,其中男性为74.18°±31.04°;女性为70.74°±31.08°。3左、右冠状动脉开口位置:位于窦内者分别占78.57%、81.43%,位于窦管结合处者分别占15.71%、14.29%,位于窦外者分别占5.72%、4.29%。4左主干长度平均为(10.49±4.08)mm。其中男性平均为(10.63±4.48)mm;女性平均为(10.29±3.53)mm。5冠状动脉变异情况:左、右冠状动脉开口高位者各1例;双开口10例;右冠状动脉缺如1例;心肌桥9例;冠状动脉瘘1例。结论:320排动态容积CT可清晰显示冠状动脉正常解剖结构及变异情况,对于指导CAG及PCI有重要临床意义。     

多层螺旋CT后处理技术对颈面部血管性病变的诊断价值初探

目的:探讨多层螺旋CT后处理技术对颈面部血管性病变的诊断价值。方法:22个颈面部血管异常的病例,行CT增强扫描后以各种后处理技术如VR、MPR、MIP、SSD等方法进行重建。结果:22例颈面部血管畸形,其中动脉瘤6例,动静脉畸形16例,二维和三维图像对病人定位的准确性均较高(86.4%<95.5%)。但在来源血管(45.5%<91.7%)、病变走行(68.2%<100%)、与周围组织的关系(72.7%<100%)等方面,3D重建图像均较2D图像显示出了明显的优势。结论:多层螺旋CT各种后处理技术的综合应用对颈面部血管性病变有较高的诊断价值。     

不同重建方法对多层螺旋CT诊断肋骨骨折准确性的影响

目的探讨多层螺旋CT检查的不同重建方法在诊断肋骨骨折的价值。方法收集37例胸部外伤患者X线片疑有骨折的病例,进行多层螺旋CT检查及多种图像后处理,观察几种不同图像对骨折显示效果。结果X线检查共发现肋骨骨折48处,肋软骨骨折0处。通过多层螺旋CT扫描后进行图像后处理共检出肋骨骨折77处,肋软骨骨折4处。两种检查方法对于肋骨、肋软骨骨折的检出比较差异有统计学意义。(χ2=39.652,P=0.000;χ2=4.101,P=0.043)。多层螺旋CT检查,曲面MPR图像检出移位肋骨骨折39处,未移位肋骨骨折38处。VRT重建图像检出移位肋骨骨折38处,未移位肋骨骨折30处。两种重建方法对于未移位肋骨骨折的检出比较差异有统计学意义。(χ2=8.941,P=0.003)。结论多层螺旋CT的曲面MPR图像可清晰显示未移位细微骨折线,VRT重建图像立体感强,可多角度观察骨折的移位。多层螺旋CT检查对于判断肋骨,尤其是肋软骨骨折有很高的诊断价值,明显优于X线检查,应为诊断肋骨骨折的可靠依据。     

Determination of normal splenic volume on computed tomography in relation to age, gender and body habitus

The purpose of our study was to examine variations in normal splenic size in relation to age, gender and body habitus in vivo, and to determine normative data for splenic volume on CT. The width (W), length (L), thickness (Th), cross-sectional areas and volume (Vol) of the spleen were obtained from abdominal CT examinations of 140 patients who underwent CT for indications unrelated to splenic disease. Splenic volume did not vary significantly (–0.04 < r < 0.05, p > 0.10) with the patient's age, gender, height, weight, body mass index or the diameter of the first lumbar vertebra, the latter considered as representative of body habitus on CT. The mean value of the measured splenic volume (S Vol) was 214.6 cm³ with a range from 107.2 to 314.5 cm³. S Vol correlated well with all the linear and the maximal cross-sectional area measurements and could be calculated using the formula: S Vol = 30 + 0.58 (W × L × Th.). Employing the same formula splenic volume was reliably assessed in 47 patients with clinically evident splenomegaly. Quantitative assessment of splenic volume might be of value in assessing mild variations in splenic size, because splenomegaly is the most common manifestation of splenic involvement in many disorders. Received 29 January 1996; Revision received 24 June 1996; Accepted 15 July 1996     

64层螺旋CT多平面重组显示肺叶间裂变异的价值

目的观察肺叶间裂及变异在64层螺旋CT多平面重组（MPR）的显示及分布。方法64层螺旋CT以0．6mm层厚采样扫描1235例胸部病变患者，使用MPR技术显示肺叶间裂及变异（包括附属裂）。结果1235例患者中肺叶间裂无变异者占80．08％（989例），变异者占19、92％（246例）。变异肺中，双侧变异20．33％（50例）；单侧变异79．67％（196例），其中右肺变异63．01％（155例），左肺16．66％（41例）。右肺既无斜裂亦无水平裂1．22％（3例），左肺无斜裂（6．91％，17例）比右肺多（3．65％，9例）。左肺斜裂不全（8．53％，21例）比右肺多（4．06％，10例）。246例中右肺无水平裂27．24％（67例），水平裂不全9．76％（24例）。肺附属裂83．33％（205例），右肺（53．66％，132例）比左肺多（29．67％，73例），右下叶段（40．65％，100例）明显高于左下叶段（7．72％，19例），舌裂15．85％（39例）。斜裂和水平裂形态和位置改变41．06％（101例），右侧（35．37％，87例）高于左侧（5．69％，14例）。结论64层螺旋CTMPR完全能显示肺叶间裂、肺叶间裂变异和附属裂，而且能区别病变和小血管。     

Correlation of magnetic resonance signal characteristics and perfusion parameters assessed by volume perfusion computed tomography in hepatocellular carcinoma: Impact on lesion characterization

AIMTo find out if magnetic resonance (MR)-signal characteristics of hepatocellular carcinomas (HCC) correlate with perfusion parameters assessed by volume perfusion computed tomography (VPCT).METHODSFrom October 2009 to January 2014, 26 (mean age, 69.3 years) patients with 36 HCC lesions who underwent both VPCT and MR liver imaging were analysed. We compared signal intensity in the T1w- and T2w-images and wash-in/wash-out kinetics on post-contrast MR images with mean values of blood flow (BF, mL/100 mL per minute), blood volume (BV, mL/100 mL), k-trans (mL/100 mL per minute), arterial liver perfusion (mL/100 mL per minute), portal venous perfusion and hepatic perfusion index (HPI, %) obtained by VPCT. Signal intensity on magnetic resonance imaging (MRI) was classified hyper/iso/hypointense compared with surrounding liver parenchyma.RESULTSSignal intensity on native T1w- and T2w-images was hyper/iso/hypo in 4/16/16 and 21/14/1 lesions, respectively. Wash-in and wash-out contrast kinetics were found on MRI in 33 of 36 lesions (91.7%) and 25 of 36 lesions (69.4%), respectively. The latter was observed significantly more often in higher graded lesions (P < 0.005). HPI was 94.7% ± 6.5%. There was no significant relationship between lesion’s MR-signal intensity, MR signal combinations, size and any of the VPCT-perfusion parameters. However HPI was constantly high in all HCC lesions.CONCLUSIONVPCT parameters add limited value to MR-lesion characterization. However in HCC lesions with atypical MR signal characteristics HPI can add a parameter to ensure HCC diagnosis.     

Influence of vascular filling and perfusion on BOLD contrast during reactive hyperemia in human skeletal muscle.

Mechanisms generating BOLD contrast are complex and depend on parameters that are prone to large variations, in particular in skeletal muscle. Here, we simultaneously measured perfusion by ASL, and BOLD response in the calf muscle of 6 healthy volunteers during post-ischemic reactive hyperemia. We tested whether the relation between the two was altered for varying degrees of leg vascular replenishment induced by prior positioning of the leg at different heights relative to the heart. We found that the BOLD response depended on perfusion, but also on the degree of repletion of leg blood vessels. We conclude that simultaneous determination of perfusion by ASL is important to identify the mechanisms underlying BOLD contrast in the skeletal muscle.     

Applicability of 3.0 T MRI images in the estimation of full age based on shoulder joint ossification: Single-centre study

Skeletal maturity is evaluated by many radiological methods for forensic age estimation. Direct radiography and computed tomography lead to a rise in ethical concerns due to radiation exposure. Therefore, magnetic resonance imaging (MRI) has currently been used in recent studies. In this study, the ossification stage of the shoulder joint was determined retrospectively in 178 male and 109 female individuals in the age group 12 to 30 years using 3.0 T MRI. All the images were evaluated with T1-weighted turbo spin echo (T1 TSE) sequence and T1 fast low angle shot two-dimensional sequence (T1 FL2D). The combined staging method, which was defined by Kellinghaus et al. and Schmeling et al., was used. The intra- and inter-observer agreement levels were very good (κ and κ_w). There were no significant age differences between males and females in all stages. In most of the stages, the ossification of the proximal humeral epiphyses occurred earlier in females than in males. Stage 4 did not occur in either of the sexes before the 18th birthday as the youngest patients in this stage was at 19 and 18 years of age in males and females, respectively. We concluded that evaluating the ossification of the proximal humeral epiphysis with MRI imaging for forensic age estimation may be beneficial. Evaluating the same anatomical structure with different MRI sequences may be useful for accurate staging diagnosis.     

Classification of trabecular structure in magnetic resonance images based on morphological granulometries

A new method of detecting structured changes in trabecular bone, such as those associated with osteoporosis, was evaluated on magnetic resonance images of the wrist. The method was based on gray-scale morphological granulometries which classify image texture by iteratively filtering an image and measuring the rate of change of structural diminution in a filtered-image sequence. A classification scheme capable of distinguishing structural changes in trabecular bone starting from normal trabeculae through sclerotic, cystic, and grossly porotic bone is presented. Results of the application of this technique to the evaluation of high resolution magnetic resonance images of the wrist are presented.     

Effect of vascular crushing on FAIR perfusion kinetics, using a BIR-4 pulse in a magnetization prepared FLASH sequence.

Flow-sensitive alternating inversion recovery (FAIR) perfusion imaging suffers from high vascular signal, resulting in artifacts and overestimation of perfusion. With TurboFLASH acquisition, crushing of vascular signal by bipolar gradients after each excitation is difficult due to the requirement of an ultrashort repetition time. Therefore, insertion of a preparation phase in the FAIR sequence, after labeling and prior to TurboFLASH acquisition, is proposed. A segmented adiabatic BIR-4 pulse, interleaved with crusher gradients, was used for flow crushing. The effect of the crusher preparation is shown as a function of crusher strength for a flow phantom and in rat brain. Influence of crusher strength on the time-dependent FAIR signal from rat brain was also measured. Signal from flowing spins in a flow phantom and from arterial spins in rat brain was significantly suppressed. Image quality was improved and the overestimation of perfusion at short inflow times was eliminated.     

Automated myocardial edge detection on MR images: Accuracy in consecutive subjects

The authors previously demonstrated the feasibility of graph-searching-based automated edge detection in cardiac magnetic resonance (MR) imaging. To further assess the clinical utility of this method, unselected images from 11 consecutive subjects undergoing clinically indicated (except for one healthy volunteer) short-axis spin-echo MR imaging were analyzed. A total of 142 images from the 11 subjects, encompassing the left ventricle from apex to outflow tract, were analyzed. The computer algorithm correctly identified complete endocardial and epicardial contours in 121 of 142 images (85%). Correlations between observerbraced and computer-derived epicardial areas for all images were good (r = .71 for epicardium, r = .83 for endocardium); they improved for a subset of higherquality images (r = .82 for epicardium, r = .92 for endocardium). The authors conclude that the current data further support the usefulness of computer digital image processing in geometric analysis of cardiac MR image data.     

层面组织结构含量与SSDE在腹盆部CT扫描中的相关性研究

目的探讨腹盆部CT扫描中层面内组织结构含量与体型特异性剂量估算值(size specific dose estimate,SSDE)的相关性。方法连续收集我院106例腹盆部平扫的患者,记录每例患者的容积CT剂量指数(volume CT dose index,CTDI vol)及体质量指数(body mass index,BMI)。测量每例患者中心层面面积(A ROI)及平均CT值(CT ROI),计算每例患者的水等效直径(water equivalent diameter,d w)、体型转换系数(size dependent specific conversion factor,f)及体型特异性剂量估算值(size specific dose estimate,SSDE)。利用QCT测量分析软件测量中心层面组织结构的含量,比较层面内各组织结构与SSDE相关性及相关程度。结果层面内脂肪与SSDE强相关(r=0.632,P<0.05),而肌肉和骨组织与SSDE的相关性无统计学意义(r=0.038,P>0.05;r=0.023,P>0.05)。层面内脂肪含量和BMI与f存在很好的线性负相关(R 2=0.812,P<0.05;R 2=0.663,P<0.05)。结论层面内脂肪含量与SSDE相关性很好,可潜在估算成人腹盆部CT扫描时所受的辐射剂量。     

代谢综合征和自发性高血压大鼠血管结构及功能差异的研究

目的观察代谢综合征（MS）大鼠大、中、小动脉结构和功能的改变,明确MS的血管损害特征。方法将实验大鼠分为MS组、正常对照组（NC）、自发性高血压组（SHR）、高血压对照组（WKY）。以HE染色进行形态学观察,并检测离体主动脉环反应性和主动脉eNOS、iNOS、RhoA／ROCK蛋白含量。结果除血管壁增厚、内膜和平滑肌细胞增生外,MS大鼠的大、中动脉有明显炎细胞浸润,小动脉出现玻璃样变性,与SHR形成区别。MS大鼠血管环舒张功能较NC组明显减弱,而SHR的收缩反应较WKY组显著增强。MS大鼠主动脉的RhoA、ROCK表达增多,但较SHR少,eNOS和iNOS表达两组均减少,组间无明显差异。结论MS时动脉结构和功能的损害较SHR更为严重和广泛,其分子机制与RhoA、ROCK系统的激活和NOS表达减少有关。     

Robust tissue–air volume segmentation of MR images based on the statistics of phase and magnitude: Its applications in the display of susceptibility‐weighted imaging of the brain

Purpose

To develop a robust algorithm for tissue–air segmentation in magnetic resonance imaging (MRI) using the statistics of phase and magnitude of the images.

Materials and Methods

A multivariate measure based on the statistics of phase and magnitude was constructed for tissue–air volume segmentation. The standard deviation of first‐order phase difference and the standard deviation of magnitude were calculated in a 3 × 3 × 3 kernel in the image domain. To improve differentiation accuracy, the uniformity of phase distribution in the kernel was also calculated and linear background phase introduced by field inhomogeneity was corrected. The effectiveness of the proposed volume segmentation technique was compared to a conventional approach that uses the magnitude data alone.

Results

The proposed algorithm was shown to be more effective and robust in volume segmentation in both synthetic phantom and susceptibility‐weighted images of human brain. Using our proposed volume segmentation method, veins in the peripheral regions of the brain were well depicted in the minimum‐intensity projection of the susceptibility‐weighted images.

Conclusion

Using the additional statistics of phase, tissue–air volume segmentation can be substantially improved compared to that using the statistics of magnitude data alone. J. Magn. Reson. Imaging 2009;30:722–731. © 2009 Wiley‐Liss, Inc.     

Analysis of the anatomical features of pulmonary veins on pre-procedural cardiac CT images resulting in incomplete cryoballoon ablation for atrial fibrillation

BackgroundTo investigate the anatomical features related to the failure of cryoballoon (CB) ablation for atrial fibrillation (AF) on pre-procedural CT images.MethodsWe retrospectively analyzed CT images of 100 patients with AF who had undergone a first CB ablation at our institution between June 2016 and April 2017. We measured the angle, short- and long axis length, and the area and ovality of 4 major pulmonary vein (PV) ostium on CT images. We performed logistic regression analysis to analyze the anatomical features related to the failure (incomplete CB ablation) of PV isolation. We also performed a receiver-operating characteristic (ROC) curve analysis to identify an appropriate cut-off value for anatomical features significantly associated with incomplete CB ablation.ResultsWe analyzed 400 PVs in 100 patients [aged 64 (range, 27–82) years, 59% male]. The rate of incomplete CB ablation was significantly higher for right-than left-sided PVs (p < 0.001). The anatomical feature significantly associated with incomplete CB ablation was the angle at the right inferior PV (RIPV) (AOR: 1.17; 95% CI: 1.09–1.27, p < 0.001) and the right superior PV (RSPV) (AOR: 1.12; 95% CI: 1.01–1.23; p = 0.014). In the ROC analysis, the optimal cut-off value for RIPV and RSPV angle to discriminate an incomplete CB ablation were 40.1° and 79.7°, respectively.ConclusionOur findings may help to select the appropriate ablation strategy to treat patients with AF. We show that the angle is an anatomical feature significantly related to failed CB ablation.