PD, Proton density

PD,质子密度
  • 文章类型: Case Reports
    第一例滑膜肉瘤发表于1893年。该疾病是软组织的一种原发性恶性肿瘤。这是一种组织起源不明的罕见侵袭性肿瘤,具有强转移潜力和不良预后。目前,一名64岁的男性患者右肩疼痛和肿胀,运动逐渐丧失,这表明肿瘤的位置不常见。磁共振质子密度脂肪抑制的涡轮自旋回波序列在右肩显示出异质质量。信号中缺乏同质性在医学文献中被描述为“三重符号”,并表示为低,中间,和通过肿瘤的高信号强度区域。可见的蛇形血管通过肿瘤扩散。区域淋巴结中有可见的转移性疾病,相邻骨骼中有转移灶。肿瘤的病理分析证实了双相滑膜肉瘤的诊断。肿瘤委员会建议化疗和放疗。在滑膜肉瘤中,可能有助于诊断过程的更突出的磁共振成像发现是质子密度和T2序列中的不均匀性和“三重符号”。多小叶肿瘤,隔片,不规则的边界,蛇形血管通道,相邻骨骼和骨髓的接合,和关节滑膜的参与。
    The first case of synovial sarcoma was published in 1893. The disease is a type of primary malignancy of the soft tissues. It is a rare and aggressive neoplasm of unknown tissue origin, characterized by strong metastatic potential and poor prognosis. The present case of a 64-year-old male patient with pain and swelling in his right shoulder and progressive loss of movement demonstrates an uncommon location for the neoplasm. Magnetic resonance proton-density fat-suppressed turbo spin-echo sequences show a heterogeneous mass in the right shoulder. The lack of homogeneity in the signal has been described in medical literature as the \"triple sign\" and is represented by low, intermediate, and high signal intensity areas through the neoplasm. Visible serpentine vessels spread through the tumor. There was a visible metastatic disease in the regional lymph nodes and metastatic foci in the adjacent bones. Pathological analysis of the tumor confirmed the diagnosis of biphasic synovial sarcoma. An oncological committee advised chemotherapy and radiotherapy. More prominent magnetic resonance imaging findings in synovial sarcoma that may facilitate the diagnostic process are the inhomogeneity and \"triple sign\" in proton density and T2 sequences, multilobulated tumors, septa, irregular borders, serpentine vascular channels, engagement of the adjacent bones and bone marrow, and involvement of the joint synovia.
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  • 文章类型: Journal Article
    目的:具有扩散加权图像的双参数磁共振成像(bpMRI)在诊断有临床意义的前列腺癌(csPCa)中具有广泛的实用性。然而,与具有动态对比增强(DCE)-MRI的多参数(mp)MRI相比,bpMRI对PI-RADS3类病变产生更多的假阴性。我们研究了具有弛豫图的合成MRI用于基于bpMRI的csPCa诊断的实用性。
    方法:前瞻性纳入了2019年8月至2020年12月期间因疑似PCa而在前列腺活检前接受了mpMRI和合成MRI的未接受治疗的患者。三位专家和三位基础前列腺放射科医生评估了常规bpMRI和合成bpMRI对csPCa的诊断性能。PI-RADS2.1版第3类病变通过共识确定,和弛豫测量(T1值,T2值,和质子密度[PD])进行。将弛豫测量对周围区PI-RADS3类病变的诊断性能与DCE-MRI的诊断性能进行了比较。使用组织病理学评估结果作为参考标准。使用受试者工作特征曲线下面积(AUC)和McNemar检验进行统计学分析。
    结果:在102例无明显MRI伪影的患者中,对于所有读者,常规bpMRI的诊断性能与合成bpMRI的诊断性能无显著差异(p=0.11~0.79).T1值组合的AUC,T2值,PI-RADS3类病变的外周区csPCa的PD(T1+T2+PD)专家为0.85,基础放射科医生为0.86,对于专家和基础放射科医师,T1T2PD和DCE-MRI之间没有显着差异(p=0.29-0.45)。
    结论:具有弛豫测量图的合成MRI显示了对csPCa无造影剂评估的希望。
    OBJECTIVE: Bi-parametric magnetic resonance imaging (bpMRI) with diffusion-weighted images has wide utility in diagnosing clinically significant prostate cancer (csPCa). However, bpMRI yields more false-negatives for PI-RADS category 3 lesions than multiparametric (mp)MRI with dynamic-contrast-enhanced (DCE)-MRI. We investigated the utility of synthetic MRI with relaxometry maps for bpMRI-based diagnosis of csPCa.
    METHODS: One hundred and five treatment-naïve patients who underwent mpMRI and synthetic MRI before prostate biopsy for suspected PCa between August 2019 and December 2020 were prospectively included. Three experts and three basic prostate radiologists evaluated the diagnostic performance of conventional bpMRI and synthetic bpMRI for csPCa. PI-RADS version 2.1 category 3 lesions were identified by consensus, and relaxometry measurements (T1-value, T2-value, and proton density [PD]) were performed. The diagnostic performance of relaxometry measurements for PI-RADS category 3 lesions in peripheral zone was compared with that of DCE-MRI. Histopathological evaluation results were used as the reference standard. Statistical analysis was performed using the areas under the receiver operating characteristic curve (AUC) and McNemar test.
    RESULTS: In 102 patients without significant MRI artefacts, the diagnostic performance of conventional bpMRI was not significantly different from that of synthetic bpMRI for all readers (p = 0.11-0.79). The AUCs of the combination of T1-value, T2-value, and PD (T1 + T2 + PD) for csPCa in peripheral zone for PI-RADS category 3 lesions were 0.85 for expert and 0.86 for basic radiologists, with no significant difference between T1 + T2 + PD and DCE-MRI for both expert and basic radiologists (p = 0.29-0.45).
    CONCLUSIONS: Synthetic MRI with relaxometry maps shows promise for contrast media-free evaluation of csPCa.
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  • 文章类型: Journal Article
    UNASSIGNED: Smoking is a poor prognostic factor for healing after rotator cuff repair and is associated with inferior results. We hypothesized that smokers would have higher recurrent tear rates and more postoperative myotendinous junction (MTJ) retraction in healed repairs than nonsmokers three months postoperatively.
    UNASSIGNED: Rotator cuff repairs (RCRs) were retrospectively reviewed over a 2-year period. Patients underwent magnetic resonance imaging (MRI) within 6 months prior to surgery and again at 3 months postoperatively. Seventy-nine patients were included and stratified by smokers versus nonsmokers. Baseline patient demographics, tear characteristics, and surgical factors were collected. Preoperative and postoperative MRIs were assessed to quantify the MTJ position and to establish the recurrent tear rate.
    UNASSIGNED: For the total cohort (nonsmokers, n = 56; smokers, n = 23), significant differences in age, race, and traumatic onset of injury existed between groups. There were no significant differences in recurrent tear between smokers (26%) and nonsmokers (27%), but nonsmokers were more satisfied. For patients with healed RCRs (nonsmokers, n = 41; smokers, n = 17), there were significant differences in race. On univariate analysis, nonsmokers had a significantly more lateral MTJ postoperatively (P = 0.05). On multivariable regression analysis, medialized postoperative MTJ position in healed cuffs was driven only by greater preoperative rotator cuff retraction preoperatively. There were no significant differences in MTJ position based on smoking status for patients with healed RCRs.
    UNASSIGNED: Smoking does not appear to be an independent risk factor for postoperative MTJ retraction in healed RCRs, also known as failure in continuity. Preoperative tear size and retraction play the biggest roles in predicting postoperative MTJ position, regardless of smoking status. There are no significant differences in patient-reported outcomes for patients with healed RCRs, but nonsmokers had more satisfaction following RCR in the total cohort.
    UNASSIGNED: Level III; Retrospective cohort study; Diagnostic study.
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  • 文章类型: Journal Article
    检查肱骨软骨T2映射值与肩袖病理之间的关系。
    59名受试者(年龄48.2±13.5岁,15名无症状志愿者和10名肌腱病,13部分厚度撕裂,8全厚度撕裂,和13名大量撕裂患者)接受了肱骨软骨T2标测。肱骨头软骨在矢状面和冠状面上分段。关节盂软骨在冠状面分段。计算每个区域的组平均值并在组间进行比较。
    对于矢状中包含的肱骨头软骨,大撕裂组T2值明显高于无症状组值(45±7对32±4ms,p<.001)和冠状(44±6对38±1ms,p=0.01)平面图像。大体积泪液的平均T2也显着高于全厚度泪液(45±7对38±5ms,p=0.02),大量大于部分厚度的撕裂(45±7对34±4ms,p<0.001),和大量眼泪比肌腱病(45±7对35±4ms,p=0.001)在肱骨头矢状图像中,大量撕裂明显高于无症状的肩部(44±6对38±1ms,在肱骨头区域的冠状图像中,p=0.01)。
    肱骨头软骨T2值与肩袖病理严重程度呈显著正相关。相对于无/较小程度的肩袖病理的受试者,大量肩袖撕裂患者表现出明显更高的肱骨头上软骨T2映射值。
    UNASSIGNED: To examine the relationship between glenohumeral cartilage T2 mapping values and rotator cuff pathology.
    UNASSIGNED: Fifty-nine subjects (age 48.2 ± 13.5 years, 15 asymptomatic volunteers and 10 tendinosis, 13 partial-thickness tear, 8 full-thickness tear, and 13 massive tear patients) underwent glenohumeral cartilage T2 mapping. The humeral head cartilage was segmented in the sagittal and coronal planes. The glenoid cartilage was segmented in the coronal plane. Group means for each region were calculated and compared between the groups.
    UNASSIGNED: Massive tear group T2 values were significantly higher than the asymptomatic group values for the humeral head cartilage included in the sagittal (45 ± 7 versus 32 ± 4 ms, p <  .001) and coronal (44 ± 6 versus 38 ± 1 ms, p =  0.01) plane images. Mean T2 was also significantly higher for massive than full-thickness tears (45 ± 7 versus 38 ± 5 ms, p =  0.02), massive than partial-thickness tears (45 ± 7 versus 34 ± 4 ms, p <  0.001), and massive tears than tendinosis (45 ± 7 versus 35 ± 4 ms, p =  0.001) in the sagittal-images humeral head region and significantly higher for massive tears than asymptomatic shoulders (44 ± 6 versus 38 ± 1 ms, p =  0.01) in the coronal-images humeral head region.
    UNASSIGNED: Humeral head cartilage T2 values were significantly positively correlated with rotator cuff pathology severity. Massive rotator cuff tear patients demonstrated significantly higher superior humeral head cartilage T2 mapping values relative to subjects with no/lesser degrees of rotator cuff pathology.
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  • 文章类型: Journal Article
    Prader-Willi综合征(PWS)是一种基因组印记的神经发育障碍,表现出特有的暴饮暴食障碍,轻度至中度智力残疾,以及可变范围的社会和行为困难。因此,预计神经结构、发育和成熟轨迹会发生广泛的变化。迄今为止,关于PWS的脑形态学的定量和系统研究很少,尽管已经报道了体积和皮质组织的改变。本研究旨在调查,在细节上,在匹配良好的病例对照分析中,患有PWS的年轻成年人的大脑灰质和皮质结构。20名患有PWS的年轻人,19-27岁,接受了多参数映射磁共振成像序列,灰质体积的度量,皮质厚度和磁化转移饱和度,作为髓鞘形成的替代量度,进行了检查。与40名通常正在发育的年轻人的对照组相比,研究了这些变量,年龄和性别相匹配。基于体素的形态计量学分析确定了PWS中大脑中灰质体积增加和减少的大型和广泛的双侧簇。特别是,体积增加的广泛区域包括前额叶皮层的一部分,尤其是中介,大部分扣带回皮质,从前部到后部,岛皮层,顶叶和颞叶皮质的区域。据报道,尾状中的体积也增加,壳核和丘脑。最腹内侧的前额区,相比之下,显示体积减少,内侧颞叶的部分也是如此,双侧颞极,和一个位于右侧前额叶皮层的小簇。对皮质结构的分析表明,PWS组中体积增加的区域很大程度上是由更大的皮质厚度驱动的。相反,使用磁化转移饱和度分析髓鞘含量表明,PWS和对照组的皮质髓鞘形成大致相似,除了高度本地化的地区,包括脑岛.这些异常的双侧性质表明是全身性生物学原因,讨论了可能的发育和成熟机制,并可能提供有关印迹基因对神经发育的贡献的见解。
    Prader-Willi syndrome (PWS) is a neurodevelopmental disorder of genomic imprinting, presenting with a characteristic overeating disorder, mild to moderate intellectual disability, and a variable range of social and behavioral difficulties. Consequently, widespread alterations in neural structure and developmental and maturational trajectory would be expected. To date, there have been few quantitative and systematic studies of brain morphology in PWS, although alterations of volume and of cortical organisation have been reported. This study aimed to investigate, in detail, the structure of grey matter and cortex in the brain in a sample of young adults with PWS in a well-matched case-controlled analysis. 20 young adults with PWS, aged 19-27 years, underwent multiparameter mapping magnetic resonance imaging sequences, from which measures of grey matter volume, cortical thickness and magnetisation transfer saturation, as a proxy measure of myelination, were examined. These variables were investigated in comparison to a control group of 40 typically developing young adults, matched for age and sex. A voxel-based morphometry analysis identified large and widespread bilateral clusters of both increased and decreased grey matter volume in the brain in PWS. In particular, widespread areas of increased volume encompassed parts of the prefrontal cortex, especially medially, the majority of the cingulate cortices, from anterior to posterior aspects, insula cortices, and areas of the parietal and temporal cortices. Increased volume was also reported in the caudate, putamen and thalamus. The most ventromedial prefrontal areas, in contrast, showed reduced volume, as did the parts of the medial temporal lobe, bilateral temporal poles, and a small cluster in the right lateral prefrontal cortex. Analysis of cortical structure revealed that areas of increased volume in the PWS group were largely driven by greater cortical thickness. Conversely, analysis of myelin content using magnetisation transfer saturation indicated that myelination of the cortex was broadly similar in the PWS and control groups, with the exception of highly localised areas, including the insula. The bilateral nature of these abnormalities suggests a systemic biological cause, with possible developmental and maturational mechanisms discussed, and may offer insight into the contribution of imprinted genes to neural development.
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  • 文章类型: Journal Article
    Diagnosis of amyotrophic lateral sclerosis (ALS) depends on clinical evidence of combined upper motor neuron (UMN) and lower motor neuron (LMN) degeneration, although ALS patients can present with features predominantly of one or the other. Some UMN-predominant patients show hyperintense signal along the intracranial corticospinal tract (CST) on T2- and proton density (PD)-weighted images (ALS-CST +), and appear to have faster disease progression when compared to those without CST hyperintensity (ALS-CST -). The reason for this is unknown. We hypothesized that diffusion tensor tractography (DTT) would reveal differences in DTI abnormalities along the intracranial CST between these two patient subgroups. Clinical DTI scans were obtained at 1.5T in 14 neurologic controls and 45 ALS patients categorized into two UMN phenotypes based on clinical measures and MRI. DTT was used to quantitatively assess the CST in control and ALS groups. DTT revealed subcortical loss (\'truncation\') of virtual motor CST fibers (presumably) projecting from the precentral gyrus (PrG) in ALS patients but not in controls; in contrast, virtual fibers (presumably) projecting to the adjacent postcentral gyrus (PoG) were spared. No significant differences in virtual CST fiber length were observed between controls and ALS patients. However, the frequency of CST truncation was significantly higher in the ALS-CST + subgroup (9 of 21) than in the ALS-CST - subgroup (4 of 24; p = 0.049), suggesting this finding could differentiate these ALS subgroups. Also, because virtual CST truncation occurred only in the ALS patient group and not in the control group (p = 0.018), this DTT finding could prove to be a diagnostic biomarker of ALS. Significantly shorter disease duration and faster disease progression rate were observed in ALS patients with CST fiber truncation than in those without (p < 0.05). DTI metrics of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) were also determined in four regions of interest (ROIs) along the CST, namely: cerebral peduncle (CP), posterior limb of internal capsule (PLIC), centrum semiovale at top of lateral ventricle (CSoLV) and subcortical to primary motor cortex (subPMC). Of note, FA values along the left hemisphere virtual CST tract were significantly different between controls and ALS-CST + patients (p < 0.05) only at the PLIC level, but not at the CSoLV or subPMC level. Also, no significant differences in FA values were observed between ALS subgroups or between control and ALS-CST - groups (p > 0.05) in any of the ROIs. In addition, comparing FA values between ALS patients with CST truncation and those without in the aforementioned four ROIs, revealed no significant differences in either hemisphere. However, visual evaluation of DTT was able to identify UMN degeneration in patients with ALS, particularly in those with a more aggressive clinical disease course and possibly different pathologic processes.
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  • 文章类型: Journal Article
    所呈现的数据集提供了体内健康大鼠大脑的规范高分辨率三维(3D)大分子质子分数(MPF)图以及用于其重建的源图像。这些图像是使用其他地方描述的协议获取的(Naumova,etal.高分辨率三维大分子质子分数作图,用于超高磁场中啮齿动物大脑的定量神经解剖成像。神经影像(2016)doi:10.1016/j。neuroimage.2016.09.036).该图是根据具有不同对比度权重(质子密度,T1和磁化转移)使用具有合成参考图像的单点算法。在具有170µm3的各向同性空间分辨率和总采集时间约1.5h的11.7T小动物MRI扫描仪上从活体动物获取源图像。3D数据集可用于多种目的,包括交互式观察大鼠大脑解剖结构,测量各种大脑结构中的参考MPF值,鼠脑分割图像处理技术的发展。它也可以作为实施和优化啮齿动物脑MRI协议的黄金标准图像。
    The presented dataset provides a normative high-resolution three-dimensional (3D) macromolecular proton fraction (MPF) map of the healthy rat brain in vivo and source images used for its reconstruction. The images were acquired using the protocol described elsewhere (Naumova, et al. High-resolution three-dimensional macromolecular proton fraction mapping for quantitative neuroanatomical imaging of the rodent brain in ultra-high magnetic fields. Neuroimage (2016) doi: 10.1016/j.neuroimage.2016.09.036). The map was reconstructed from three source images with different contrast weightings (proton density, T1, and magnetization transfer) using the single-point algorithm with a synthetic reference image. Source images were acquired from a living animal on an 11.7 T small animal MRI scanner with isotropic spatial resolution of 170 µm3 and total acquisition time about 1.5 h. The 3D dataset can be used for multiple purposes including interactive viewing of rat brain anatomy, measurements of reference MPF values in various brain structures, and development of image processing techniques for the rodent brain segmentation. It also can serve as a gold standard image for implementation and optimization of rodent brain MRI protocols.
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  • 文章类型: Journal Article
    Obstructive sleep apnea (OSA) is accompanied by cognitive, motor, autonomic, learning, and affective abnormalities. The putamen serves several of these functions, especially motor and autonomic behaviors, but whether global and specific sub-regions of that structure are damaged is unclear. We assessed global and regional putamen volumes in 43 recently-diagnosed, treatment-naïve OSA (age, 46.4 ± 8.8 years; 31 male) and 61 control subjects (47.6 ± 8.8 years; 39 male) using high-resolution T1-weighted images collected with a 3.0-Tesla MRI scanner. Global putamen volumes were calculated, and group differences evaluated with independent samples t-tests, as well as with analysis of covariance (covariates; age, gender, and total intracranial volume). Regional differences between groups were visualized with 3D surface morphometry-based group ratio maps. OSA subjects showed significantly higher global putamen volumes, relative to controls. Regional analyses showed putamen areas with increased and decreased tissue volumes in OSA relative to control subjects, including increases in caudal, mid-dorsal, mid-ventral portions, and ventral regions, while areas with decreased volumes appeared in rostral, mid-dorsal, medial-caudal, and mid-ventral sites. Global putamen volumes were significantly higher in the OSA subjects, but local sites showed both higher and lower volumes. The appearance of localized volume alterations points to differential hypoxic or perfusion action on glia and other tissues within the structure, and may reflect a stage in progression of injury in these newly-diagnosed patients toward the overall volume loss found in patients with chronic OSA. The regional changes may underlie some of the specific deficits in motor, autonomic, and neuropsychologic functions in OSA.
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