滑车神经断层解剖与MRI

目的：探讨滑车神经在MRI图像上的识别,为滑车神经相关疾病的影像学诊断和临床治疗提供形态学依据。方法：选取国人成年尸体头部标本51例,以冷冻切片法分别制成连续横断层标本36例和连续冠状断层标本15例;采用3D—CISS序列,结合3D—TOF序列,对20名正常体检者及23例眼运动神经麻痹患者行1．5T磁共振扫描;应用3．0TMRI扫描仪,获取10例志愿者头部的SE序列T2WI图像;在上述连续断层标本和MRI图像上,观察分析滑车神经的位置、走行、毗邻及识别标志等。结果：在横断面上,滑车神经起始段走行在上髓帆后部的四叠体池内,其外侧为小脑幕切迹,后方为小脑上动脉;其环池段绕中脑大脑脚两侧的环池走行,由背侧转至腹侧。在冠状断面上,滑车神经环池段位于小脑幕下方,其外上方有大脑后动脉;其海绵窦段走行在蝶骨体两侧的海绵窦外侧壁,动眼神经的外下方。结论：横断面能较好地显示滑车神经的起始段和环池段,而冠状断面则能清晰地显示其海绵窦段。     

髌骨高度测量常用4种方法的运用与比较

背景:胫骨高位截骨是近年来较为盛行的用于治疗膝内侧间室骨关节炎的保膝手术之一,但先前文献报道该术式对髌骨高度的影响不一,其主要原因是采用了不同的髌骨高度测量方法.目的:综合评价胫骨高位截骨前后Caton-Deschamps指数、Blackburne-Peel指数、Insall-Salvati指数和改良Insall-Sa...     

A comparison of reproducibility of measurement techniques for patella position on axial radiographs after total knee arthroplasty

Patella position can be measured on axial radiographs and many measurement techniques have been described in literature. The goal of this study was to evaluate the inter- and intraobserver reproducibility of measurement techniques available in the literature for patients with a knee prosthesis. Fifty axial patella radiographs from knee prostheses were used to measure the reproducibility of five measurement techniques. Reproducibility was calculated using the Bland and Altman method. The Patellar Displacement (>or=4 mm) and the Lateral Patellar Tilt (>10 degrees) were found to be useful and clinically relevant. Based on our study we recommend that the most reproducible method to use for measurement of tilt, is Lateral Patellar Tilt; to measure displacement, the surgeon should use the Patellar Displacement technique.     

A morphological comparison of cervical spondylotic myelopathy: MRI and dissection findings

The number of people with functional disabilities has been increasing with the rapid changes of age structure in the overall population. One of the major causes of disturbances in daily activities is cervical spondylotic myelopathy (CSM). The transverse area and sagittal diameter of the spinal cord measured by MRI is reported to correlate with the clinical manifestations of CSM, the duration of the disease, and the speed of recovery after surgery in patients with CSM. The purpose of this research is to determine the morphological characteristics of CSM as seen in MRI findings including the spinal cord sagittal diameter, transverse diameter, transverse area and flatness ratio. Twenty-eight of several patients with CSM were treated conservatively after carrying out measurements by MRI. In addition, anatomical studies were carried out on the spinal cords after anatomical dissection of the vertebral column in seven cadavers with CSM. These results, when compared with the morphological analysis of the cervical spinal cord, show that there is a correlation between the transverse areas at C4, C5 and C6 levels, as those at every level of the cervical transverse areas of tissue sections in the dissection cadavers were 10-18% smaller than those in the MRI patients. These results should be taken into account for the treatment of CSM patients.     

Effective measurement of knee alignment using AP knee radiographs

The gold standard for measuring knee alignment is mechanical axis determined using full-limb radiographs (FLR). Measurement of joint alignment using antero-posterior (AP) knee radiographs is more accessible, economical and involves less radiation exposure to the patient compared with using full-limb radiographs. The aim of this study was to compare and assess the reproducibility of knee joint axial alignment on full-limb radiographs and conventional AP knee radiographs. Knee alignment was measured in 40 subjects (80 knees) from the TwinsUK registry. Measurement of mechanical knee alignment was from FLR, and anatomic knee alignment from weight-bearing AP knee radiographs. Reproducibility was assessed by intra-class correlation coefficients and kappa statistics. Reproducibility of knee alignment for both methods was good, with intra-observer ICC's of 0.99 for both FLR and AP radiographs. The mean alignment angle on FLR was 178.9 degrees (SD 2.1, range 173-183 degrees ), and 179.0 degrees (SD 2.1, range 173-185 degrees ) on AP films. 58.8% of knees on FLR and 66.3% on AP films were of varus alignment. Good correlations were seen between results for FLR and AP radiographs, with ICC ranging from 0.87-0.92 for left and right knees, and kappa statistics of 0.65-0.74. Standard AP knee radiographs can be used to measure knee alignment with good reproducibility, and provide comparable results to those obtained from FLR. This will facilitate measurement of knee alignment in existing cohort studies to assess malalignment as a risk factor of incident OA, and in clinical practice.     

A quantitative comparison of functional MRI cluster analysis

The aim of this work is to compare the efficiency and power of several cluster analysis techniques on fully artificial (mathematical) and synthesized (hybrid) functional magnetic resonance imaging (fMRI) data sets. The clustering algorithms used are hierarchical, crisp (neural gas, self-organizing maps, hard competitive learning, k-means, maximin-distance, CLARA) and fuzzy (c-means, fuzzy competitive learning). To compare these methods we use two performance measures, namely the correlation coefficient and the weighted Jaccard coefficient (wJC). Both performance coefficients (PCs) clearly show that the neural gas and the k-means algorithm perform significantly better than all the other methods using our setup. For the hierarchical methods the ward linkage algorithm performs best under our simulation design. In conclusion, the neural gas method seems to be the best choice for fMRI cluster analysis, given its correct classification of activated pixels (true positives (TPs)) whilst minimizing the misclassification of inactivated pixels (false positives (FPs)), and in the stability of the results achieved.     

Popliteus muscle sesamoid bone (cyamella): appearance on radiographs, CT and MRI

Popliteus muscle sesamoid bone, also known as cyamella, is an accessory ossicle that is located in the vicinity of the proximal musculo tendinous junction. While commonly seen in small mammals such as cats and dogs, its presence in humans is very rare. In this report, we present the radiological findings of the popliteus muscle sesamoid bone, incidentally detected in a 47-year-old male. CT and MRI features of this ossicle are described.     

Modelling height in adolescence: a comparison of methods for estimating the age at peak height velocity

Background: Controlling for maturational status and timing is crucial in lifecourse epidemiology. One popular non-invasive measure of maturity is the age at peak height velocity (PHV). There are several ways to estimate age at PHV, but it is unclear which of these to use in practice.

Aim: To find the optimal approach for estimating age at PHV.

Subjects and methods: Methods included the Preece &; Baines non-linear growth model, multi-level models with fractional polynomials, SuperImposition by Translation And Rotation (SITAR) and functional data analysis. These were compared through a simulation study and using data from a large cohort of adolescent boys from the Christ’s Hospital School.

Results: The SITAR model gave close to unbiased estimates of age at PHV, but convergence issues arose when measurement error was large. Preece &; Baines achieved close to unbiased estimates, but shares similarity with the data generation model for our simulation study and was also computationally inefficient, taking 24?hours to fit the data from Christ’s Hospital School. Functional data analysis consistently converged, but had higher mean bias than SITAR. Almost all methods demonstrated strong correlations (r?>?0.9) between true and estimated age at PHV.

Conclusions: Both SITAR or the PBGM are useful models for adolescent growth and provide unbiased estimates of age at peak height velocity. Care should be taken as substantial bias and variance can occur with large measurement error.     

MRI of the breast: comparison of MRI signals and histological characteristics of the same slices

The development of MRI with high spatial resolution and a special breast coil has contributed to more-accurate diagnosis of breast tumor, such as determination of morphologic characteristics including internal architecture of the breast lesion. To clarify how individual MRI findings reflect the pathological findings, we made slices of resected breast lesions identical to those obtained with axial MRI and compared them respectively according to histological subtype of tumors. In this article, we present MRI findings on the basis of histopathological evidence. In general, fibroadenomas (FA) show a well-defined border on contrast-enhanced fat-suppressed T₁-weighted images (CFT1). However, a subtype of fibroadenoma, mastopathic type, with a poorly defined border on CFT1 and carcinoma-like enhancement, is similar to cancer on MRI. Scirrhous carcinomas take either of two patterns on dynamic MRI, i.e., homogeneous enhancement or thick irregular peripheral ring enhancement. The latter type shows central fibrosis zones histologically. Papillotubular carcinoma shows a spotted pattern on dynamic MRI. The low-enhancement areas within the spotted pattern reflect parenchyma between clusters of cancer. Solid-tubular carcinoma shows thin peripheral enhancement on dynamic MRI and linear high signal on CFT1. This finding of CFT1 corresponds to infiltration of lymph cells and fibroblast cells in the adjacent zone. Invasive lobular carcinoma shows nonmass lesions and a slow gradual enhancement pattern. Mucinous carcinomas show high signal intensity on T₂-weighted images because of mucin and reveal gradual enhancement. The ill-defined border of mucinous carcinoma on CFT1 is useful to distinguish it from FA.     

A comparison of arterial spin labeling perfusion MRI and DCE‐MRI in human prostate cancer

Perfusion MRI has the potential to provide pathophysiological biomarkers for the evaluating, staging and therapy monitoring of prostate cancer. The objective of this study was to explore the feasibility of noninvasive arterial spin labeling (ASL) to detect prostate cancer in the peripheral zone and to investigate the correlation between the blood flow (BF) measured by ASL and the pharmacokinetic parameters K^trans (forward volume transfer constant), k_ep (reverse reflux rate constant between extracellular space and plasma) and v_e (the fractional volume of extracellular space per unit volume of tissue) measured by dynamic contrast‐enhanced (DCE) MRI in patients with prostate cancer. Forty‐three consecutive patients (ages ranging from 49 to 86 years, with a median age of 74 years) with pathologically confirmed prostate cancer were recruited. An ASL scan with four different inversion times (TI = 1000, 1200, 1400 and 1600 ms) and a DCE‐MRI scan were performed on a clinical 3.0 T GE scanner. BF, K^trans, k_ep and v_e maps were calculated. In order to determine whether the BF values in the cancerous area were statistically different from those in the noncancerous area, an independent t‐test was performed. Spearman's bivariate correlation was used to assess the relationship between BF and the pharmacokinetic parameters K^trans, k_ep and v_e. The mean BF values in the cancerous areas (97.1 ± 30.7, 114.7 ± 28.7, 102.3 ± 22.5, 91.2 ± 24.2 ml/100 g/min, respectively, for TI = 1000, 1200, 1400, 1600 ms) were significantly higher (p < 0.01 for all cases) than those in the noncancerous regions (35.8 ± 12.5, 42.2 ± 13.7, 53.5 ± 19.1, 48.5 ± 13.5 ml/100 g/min, respectively). Significant positive correlations (p < 0.01 for all cases) between BF and the pharmacokinetic parameters K^trans, k_ep and v_e were also observed for all four TI values (r = 0.671, 0.407, 0.666 for TI = 1000 ms; 0.713, 0.424, 0.698 for TI = 1200 ms; 0.604, 0.402, 0.595 for TI = 1400 ms; 0.605, 0.422, 0.548 for TI = 1600 ms). It can be seen that the quantitative ASL measurements show significant differences between cancerous and benign tissues, and exhibit strong to moderate correlations with the parameters obtained using DCE‐MRI. These results show the promise of ASL as a noninvasive alternative to DCE‐MRI. Copyright © 2014 John Wiley & Sons, Ltd.     

Carotid geometry reconstruction: a comparison between MRI and ultrasound

Image-based Computational Fluid Dynamics (CFD) has become a popular tool for the prediction of in vivo flow profiles and hemodynamic wall parameters. Currently, Magnetic Resonance Imaging (MRI) is most widely used for in vivo geometry acquisition. For superficial arteries such as the carotids and the femoral artery, three-dimensional (3-D) extravascular ultrasound (3-DUS) could be a cost-effective alternative to MRI. In this study, nine healthy subjects were scanned both with MRI and 3-DUS. The reconstructed carotid artery geometries for each subject were compared by evaluating cross-sectional areas, centerlines, and carotid nonplanarity. Lumen areas agreed very well between the two different acquisition techniques, whereas centerlines and nonplanarity parameters showed measurable disagreement, possibly due to the different neck and head positions adopted for 3-DUS versus MRI. With the current level of agreement achieved, 3-DUS has the potential to become an inexpensive and fast alternative to MRI for image-based CFD modeling of superficial arteries.     

A quantitative measurement method for comparison of seated postures

This technical note proposes a method to measure and compare seated postures. The three-dimensional locations of palpable anatomical landmarks corresponding to the anterior superior iliac spines, clavicular notch, head, shoulders and knees are measured in terms of x, y and z co-ordinates in the reference system of the measuring apparatus. These co-ordinates are then transformed onto a body-based axis system which allows comparison within-subject. The method was tested on eleven unimpaired adult participants and the resulting data used to calculate a Least Significant Difference (LSD) for the measure, which is used to determine whether two postures are significantly different from one another.The method was found to be sensitive to the four following standardised static postural perturbations: posterior pelvic tilt, pelvic obliquity, pelvic rotation, and abduction of the thighs. The resulting data could be used as an outcome measure for the postural alignment aspect of seating interventions in wheelchairs.     

磁共振成像层厚测量技术及其改进

对磁共振成像设备层厚测量技术进行研究。利用Magphan体模在13台设备上对层厚的三种测量方法即单一斜面方法、交叉斜面方法和本文提出的改进方法（考虑几何畸变的交叉测量方法）进行层厚测量实验。实验结果表明（1）进行层厚测量时,应考虑影响层厚测量的因素,并选择合适的体模;（2)三种方法的测量结果存在一定差异,其中考虑几何畸变的交叉斜面测量方法是最好的方法,此方法得到结果最接近真实值。     

A comparison of 3D ultrasound to MRI for the measurement and estimation of gastrocnemius muscle volume in adults and young people with and without cerebral palsy

Muscle volume (MV) is an important parameter for understanding muscle morphology and adaptations to training, growth and pathology. In this study, we assessed the validity of freehand 3D ultrasound (3DUS) for measuring medial gastrocnemius MV in adults, typically developing (TD) children and children with cerebral palsy (CP). We also assessed the validity between our direct measures of MV and estimates derived from anatomical cross sectional area (ACSA) and muscle length (ML), using previously outlined methods. The medial gastrocnemius of all groups was scanned with 3DUS and MRI. Images from both methods were digitized to derive MV, ACSA and ML. Measured MV was compared between methods and compared to estimated MV derived from recently published algorithms. MV had a mean difference of ?0.13% (standard error of estimate (SEE) = 2.23%, R² = 0.99) between MRI and 3DUS and 19.82% (SEE = 4.73% and R² = 0.99) and ?3.11% (SEE = 6.55%, R² = 0.99) mean differences between the measured and estimated MV from two methods of estimation. The 3DUS is a valid method for the measurement of MV in adults, TD children and those with CP. Estimation methods of MV may be useful in clinical practice, but require further replication on various populations and careful methodological consideration. Clin. Anat. 32:319–327, 2019. © 2018 Wiley Periodicals, Inc.     

A comparison of tibiofemoral and patellofemoral alignment during a neutral and valgus single leg squat: an MRI study

BackgroundThe etiology of anterior knee pain is not well understood. Recently, excessive hip adduction and internal rotation have been cited as possible factors. However, how these altered hip mechanics affect the patellofemoral joint is still unclear.ObjectiveTo compare the three-dimensional tibiofemoral and patellofemoral alignment between a neutral squat and one performed with increased hip adduction and internal rotation. We aimed to examine the relationships between the three-dimensional tibiofemoral and patellofemoral alignment during a neutral and valgus squat. Finally, we aimed to determine the relationship between two-dimensional and three-dimensional measures of patellofemoral alignment.Methods10 healthy subjects were recruited for this study. Knee and patellar kinematics in a neutral squat and one performed with hip adduction and internal rotation were measured using a open, upright, magnetic resonance imaging unit. Both single leg squats were performed at 30° of knee flexion.ResultsThere was a significant correlation between knee external rotation and lateral patellar translation, and between knee abduction and lateral patellar translation. Moderate relationships were found between the 2D and 3D measures but these were not statistically significant.ConclusionThe valgus squat resulted in greater knee external rotation in all subjects. Although mean patellar mechanics were not different in the valgus squat, lateral patellar translation increased as knee external rotation increased. Lastly, 2D measures of patellofemoral alignment only provide moderately fair surrogates for 3D measures.     

Identifying saltatory growth patterns in infancy: A comparison of results based on measurement protocol

The present analyses address the question of how frequently time-intensive growth measurements need to be taken in order to provide sufficient data for the statistical identification of pulsatile saltatory growth patterns during infancy. The daily serial growth measurements of three infants during 4 months are analyzed in seven subsets, which include progressively fewer data points from daily to weekly intervals. Saltatory growth pulse identification and growth pattern analyses are compared between the temporally distinctive data sets by the saltatory algorithm and continuous curvilinear models. Statistically significant pulse identification and saltatory growth pattern resolution decrease with time intervals > 2–5 days in these data sets. These results suggest that the convenience of a Monday, Wednesday, Friday protocol may not be sufficient to characterize saltatory growth in individual infants, and the dependability factor is a significant source of error that may contribute to growth pattern misperception in data collected by infrequent protocols. Am. J. Hum. Biol. 9:343–355, 1997. © 1997 Wiley-Liss, Inc.     

正常志愿者肾脏血氧水平依赖MRI——1.5T与3.0T MRI对比

目的探讨正常志愿者肾脏血氧水平依赖(BOLD)MRI在3.0TMRI机与1.5TMRI机的区别。方法选择无肾脏疾病史的正常志愿者16例,其中男性6例,女性10例;年龄30~65岁,平均年龄54岁。禁食、水12 h,首先在3.0 T MRI机(GE Signa HDx 3.0 T MRI机)上行冠状位肾脏BOLD成像,扫描参数如下:TR为120 ms,采用8个TE(1.5、2.5、8.0、10.0、15.0、30.0、45.0、60.0 ms),卷折角30°,显示野32 cm。共采集3层图像,每层图像根据不同的TE值采集8幅图像。原始图像传至ADW 4.4工作站进行后处理。次日,同样条件,每位志愿者在1.5 T MRI机(GE Signa HDx 1.5 T MRI机)上进行BOLD扫描,条件同上。将2次所测得的双侧肾脏皮质和髓质的R2*平均值进行对比。结果双肾皮质3.0 T MRI与1.5 T MRI所测得的R2*值对比,差异有统计学意义(P<0.05);3.0 T MRI所测得的R2*值较1.5 T MRI测得的R2*值高7.53 Hz;双肾髓质3.0T MRI与1.5 T MRI所测得的R2*值对比,差异有统计学意义(P<0.05),且3.0 T MRI所测得的R2*值较1.5 T MRI测得的R2*值高15.89 Hz。结论肾脏BOLD MRI,在3.0 T MRI机所测得的R2*值高于在1.5 T MRI机上测得的R2*值,以髓质差别更加明显,说明肾脏BOLD 3.0 T MRI对肾髓质内氧含量变化更加敏感。     

A semi-automatic technique for measurement of arterial wall from black blood MRI.

Black blood magnetic resonance imaging (MRI) has become a popular technique for imaging the artery wall in vivo. Its noninvasiveness and high resolution make it ideal for studying the progression of early atherosclerosis in normal volunteers or asymptomatic patients with mild disease. However, the operator variability inherent in the manual measurement of vessel wall area from MR images hinders the reliable detection of relatively small changes in the artery wall over time. In this paper we present a semi-automatic method for segmenting the inner and outer boundary of the artery wall, and evaluate its operator variability using analysis of variance (ANOVA). In our approach, a discrete dynamic contour is approximately initialized by an operator, deformed to the inner boundary, dilated, and then deformed to the outer boundary. A group of four operators performed repeated measurements on 12 images from normal human subjects using both our semiautomatic technique and a manual approach. Results from the ANOVA indicate that the inter-operator standard error of measurement (SEM) of total wall area decreased from 3.254 mm2 (manual) to 1.293 mm2 (semi-automatic), and the intra-operator SEM decreased from 3.005 mm2 to 0.958 mm2. Operator reliability coefficients increased from less than 69% to more than 91% (inter-operator) and 95% (intra-operator). The minimum detectable change in wall area improved from more than 8.32 mm2 (intra-operator, manual) to less than 3.59 mm2 (inter-operator, semi-automatic), suggesting that it is better to have multiple operators measure wall area with our semi-automatic technique than to have a single operator make repeated measurements manually. Similar improvements in wall thickness and lumen radius measurements were also recorded. Since the semi-automatic technique has effectively ruled out the effect of the operator on these measurements, it may be possible to use such techniques to expand prospective studies of atherogenesis to multiple centers so as to increase access to real patient data without sacrificing reliability.