Real-time assessment of temporomandibular joint using HASTE sequences: feasibility and comparison with standard static sequences

Objective:To test real-time MRI (rtMRI) using HASTE sequences in patients with suspected internal disk derangement (IDD) of temporomandibular joint (TMJ) and to compare these sequences with standard static sequences.Methods and materials:99 TMJ were studied with both standard sequences (fat-saturated proton density) and HASTE sequences with high temporal resolution. Image quality was assessed using a 4-point Likert scale. Two radiologists analysed both standard and rtMRI sequences separately, randomly and blinded (by a third operator) to patients’ names in order to assess inter-observer repeatability. One of the radiologists performed the analysis twice for assessing intra-observer repeatability. The same radiologists evaluated randomly and blinded to the previous assessment both the sequences and decided in consensus which was the most credible. Qualitative scores were compared using Friedman’s test while concordance between radiologists and sequences was evaluated using the concordance correlation coefficient.Results:At image quality analysis, mean score was 3.41 for static MRI and 3.82 for rtMRI, with a statistically significant difference in favour of rtMRI (p < 0.0001). Inter-rater concordance between operator 1 (Op1) and operator 2 (Op2) with regard to the same sequence was high for both static and rtMRI sequences (0.824 and 0.888, respectively). Inter-rater variability of Op1 and Op2 between static and rtMRI sequences was lower (0.647 for Op1 and 0.633 for Op2). Among 71 discordances between sequences, 60 were judged in favour of rtMRI, while 11 were in favour of static MRI.Conclusion:rtMRI with HASTE sequences is a robust technique and provide additional information in assessing IDD compared to static sequences.     

屏气流速电影MRI评价左右心室功能的初步研究

目的:评价屏气相位流速电影法MRI(phase-velocitycineMRI,PVCMRI)测量心功能方面的价值。方法:应用PVCMRI检查了25例心脏病患者,将流速法测量的左心室搏出量(LVSV)、主动脉峰值流速(APV)、主动脉平均流速(AAV),分别与右心室搏出量(RVSV)、肺动脉峰值流速(PPV)、肺动脉平均流速(PAV)进行均值比较。结果:PVC法所测的左右心室搏出量均值比较差异无显著性,并且具有明显的直线相关关系。肺动脉AV均值要明显大于主动脉AV,并且具有明显的直线相关关系。主动脉PV要明显大于肺动脉PV,两者没有明显直线相关关系。结论:相位流速电影MRI成像可以无创监测心脏、大血管血流动力学改变,准确评价心功能,是一种有价值的检查方法。     

主动脉夹层几种磁共振影像的评价和比较

目的：评价和比较ＭＲＩＳＥ常规序列、电影（ｃｉｎｅ）ＭＲＩ及ＭＲ血管造影（ＭＲＡ）对主动脉夹层的诊断价值。材料和方法：对２５例主动脉夹层进行了３１人次ＭＲ检查。其中包括胸腹主动脉ＳＥ序列３１人次，胸主动脉ｃｉｎｅＭＲＩ２３人次及腹主动脉二维时间飞跃（２ＤＴＯＦ）ＭＲＡ２１人次。将ｃｉｎｅＭＲＩ及ＭＲＡ分别与其相应ＳＥ序列ＭＲ表现进行比较。结果：胸主动脉ｃｉｎｅＭＲＩ２３例与相应ＳＥ序列比较，两者所有病例均显示内膜片及真假两腔，但显示破口分别为１４和９例。显示头臂血管受累分别为７和２条。腹主动脉ＭＲＡ２１例与相应ＳＥ序列比较，两者均显示内膜片和真假两腔，但显示破口或再破口者分别为４和２例，腹主动脉分支血管受累分别为３９和１４条。结论：ＭＲ是诊断主动脉夹层的最佳影像学方法之一。在常规ＳＥ序列基础上，辅以ｃｉｎｅＭＲＩ和ＭＲＡ技术将大大提高ＭＲ总体观察夹层范围、内膜破口以及分支受累的能力，给临床提供更多的信息。     

青少年与成人急性髌骨外侧脱位后内侧髌股韧带损伤的MRI对比分析

目的 对比分析青少年与成人急性髌骨外侧脱位后内侧髌股韧带(MPFL)损伤的MRI特点.方法 分别对42例青少年和45例成人急性髌骨外侧脱位患者的MRI资料进行回顾性分析,87例患者均行常规MRI矢状面、冠状面和横断面T1 WI、T2WI、脂肪抑制FSE双回波序列扫描,分析MPFL的损伤特点,并应用x2检验比较青少年和成人MPFL各种损伤的发生率.结果 急性髌骨外侧脱位后,青少年组MPFL损伤发生率为97.6％ (41/42),其中完全撕裂、部分撕裂发生率分别为57.1％ (24/42)、40.5％(17/42);成人组对应的MPFL损伤发生率、完全撕裂发生率、部分撕裂发生率分别为100.0％ (45/45)、64.4％(29/45)、35.6％ (16/45);2组间MPFL损伤的发生率差异均无统计学意义(x2值分别为1.084、0.486、0.223,P值均＞0.05).青少年组MPFL股骨侧、髌骨侧、体部撕裂发生率分别为31.0％(13/42)、78.6％(33/42)和26.2％(11/42),其中多发部位损伤发生率为33.3％ (14/42);成人组对应的各发生率分别为64.4％(29/45)、40.0％(18/45)、15.6％(7/45)和15.6％ (7/45),2组间比较MPFL股骨侧、髌骨侧撕裂发生率差异有统计学意义(x2值分别为9.759、13.324,P值均＜0.05),体部撕裂发生率差异无统计学意义(x2=1.497,P＞0.05).青少年组较成人组尽管多发部位损伤差异无统计学意义(x2=3.749,P＞0.05),但青少年组更易伴发MPFL多发部位损伤.结论 青少年与成人比较,急性髌骨外侧脱位后MPFL损伤程度分布无差异,但在损伤部位分布上,二者具有显著差异,成人组损伤以股骨侧多见,其次为髌骨侧,而青少年组以髌骨侧多见,其次为股骨侧,青少年更易发生MPFL多发部位损伤.     

MRI after patellofemoral replacement: the preserved compartments

Introduction

The aim of this study was to assess the reproducibility of magnet resonance imaging (MRI) analysis of preserved anatomic structures of the knee after patellofemoral replacement (PFR). It was hypothesized that evaluation of cartilage, ligaments, meniscus and tendons would result in high inter-observer reliability after PFR.

Material and methods

MRI, tailored to reduce metallic artefacts of the knee, after PFR was performed in seven patients. Two independent investigators evaluated cartilage, menisci, collateral and cruciate ligaments, the quadriceps and patellar tendons and the presence of joint effusion. The reviewers used a five-point scale to give a degree of confidence to their evaluation of each parameter. Inter-observer reliability was determined by calculation of Cohen's Kappas.

Results

Artefact provoked by the implants was not observed. For all assessed structures, there was excellent inter-observer reliability, with high Cohen's Kappas. There were also high levels of inter-observer agreement and observer confidence in the evaluation of cartilage, meniscus, tendons, ligaments and joint effusion.

Conclusion

Tailored MRI allows reproducible analysis of the preserved knee joint structures after PFR. It might prove helpful in assessment of painful knee joints after PFR.     

Utility of delayed gadolinium-enhanced MRI (dGEMRIC) for qualitative evaluation of articular cartilage of patellofemoral joint

Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) was used for the measurement of relative proteoglycan depletion of articular cartilage in the patellofemoral (PF) joint following a proprietary protocol, which was compared with the X-ray images, proton density weighted MR images (PDWI) and arthroscopic findings. The study examined 30 knees. The ages ranged from 16 to 74 (average 40.3) years. The Gd-DTPA^2–containing contrast medium was used in a single dose. The subjects were made to exercise the knee joint for 10 min; and MR images were taken 2 h after intravenous injection of contrast medium. T1-calculated images were produced and the region of interest (ROI) was set as follows. (1) ROI1: entire articular cartilage in a slice through the center of the patella. (2) ROI2: low signal region in T1-calculated images, which were set in a blind fashion by two observers. (3) ROI3: articular cartilage on one side that includes ROI2 where low signal region were detected (medial or lateral). ROI3 was set to examine the contrast of ROI2 with surrounding articular cartilage. The average T1 values of ROI1 was 393.5±33.6 ms for radiographic grade 0 and 361.3±11.1 ms for grade I, which showed a significant difference (P=0.036). The T1 value of ROI2 was 351.6±28.2 ms for grade I, 361.9±38.3 ms for grade II, 362.1±67.7 ms for grade III, and 297.8±54.1 ms for grade IV according to arthroscopic Outerbridge classification. All cases, that demonstrated decrease of T1 values on dGEMRIC (ROI2), showed abnormal arthroscopic or direct viewing findings. The ratio (ROI3/ROI2) in cases of only slight damage classified as Outerbridge grade I (6 cases) was an average of 1.04±0.02 and was 1.0 or greater in all cases, thereby indicating well-defined contrast with the surrounding cartilage. The diagnosis of damage in articular cartilage was possible in all 16 cases with radiographic K–L grade I on dGEMRIC, while the intensity changes were not found in 10 of 16 cases on PDWI. The dGEMRIC with a single-dose would be useful on a diagnosis of the area demonstrating early relative proteoglycan depletion in the articular cartilage of the PF joint prior to any discernible changes in the subchondral bone on X-ray images and exceeds to plain MR images for examining deterioration of articular cartilage.     

膝关节交叉韧带损伤的MRI诊断

目的 :探讨MRI对膝关节交叉韧带损伤的诊断价值。方法 :回顾性分析 2 5例经手术或关节镜证实的前、后交叉韧带损伤患者 ,MR检查采用SE、TSE矢状位、冠状位及横断位T1WI、T2 WI及STIR。结果 :2 5例交叉韧带损伤中 ,部分性撕裂 16例 ,完全性撕裂 9例。MRI诊断交叉韧带部分性撕裂和完全性撕裂的符合率分别为 87.5 %和 88.9%。结论 :MR能较准确地诊断膝关节交叉韧带损伤及其并发症 ,为临床制订治疗方案提供可靠依据。     

髌股关节紊乱的MRI表现与临床

目的：探讨髌股关节紊乱(PFD)的MRI表现。方法：膝关节正常组6例(10个膝)及病例组42例(70个膝)受试者均行MRI检查,对病理性髌股关系及髌骨支持带的表现进行分析。结果：所有病例(70个膝)髌骨外侧半脱位程度6～15 mm,60％为双侧。其他恒定的异常包括股骨滑车发育不良、髌骨内侧支持带薄、髌外侧支持带增厚以及...     

Upper airway volume segmentation analysis using cine MRI findings in children with tracheostomy tubes.

OBJECTIVE: The purpose of this study is to evaluate the airway dynamics of the upper airway as depicted on cine MRI in children with tracheotomy tubes during two states of airflow through the upper airway. MATERIALS AND METHODS: Sagittal fast gradient echo cine MR images of the supra-glottic airway were obtained with a 1.5T MRI scanner on seven children with tracheotomy tubes. Two sets of images were obtained with either the tubes capped or uncapped. The findings of the cine MRI were retrospectively reviewed. Volume segmentation of the cine images to compare the airway volume change over time (mean volume, standard deviation, normalized range, and coefficient of variance) was performed for the capped and uncapped tubes in both the nasopharynx and hypopharynx (Signed Rank Test). RESULTS: Graphical representation of the airway volume over time demonstrates a qualitative increased fluctuation in patients with the tracheotomy tube capped as compared to uncapped in both the nasopharyngeal and hypopharyngeal regions of interest. In the nasopharynx, the mean airway volume (capped 2.72 mL, uncapped 2.09 mL, p = 0.0313), the airway volume standard deviation (capped 0.42 mL, uncapped 0.20 mL, p = 0.0156), and the airway volume range (capped 2.10 mL, uncapped 1.09 mL, p = 0.0156) were significantly larger in the capped group of patients. In the hypopharynx, the airway volume standard deviation (capped 1.54 mL, uncapped 0.67 mL, p = 0.0156), and the airway volume range (capped 6.44 mL, uncapped 2.93 mL, p = 0.0156) were significantly larger in the capped tubes. The coefficient of variance (capped 0.37, uncapped 0.26, p = 0.0469) and the normalized range (capped 1.52, uncapped 1.09, p = 0.0313) were significantly larger in the capped tubes. CONCLUSION: There is a statistically significant change in airway dynamics in children with tracheotomy tubes when breathing via the airway as compared to breathing via the tracheotomy tube.     

Functional cine MRI of the abdomen for the assessment of implanted synthetic mesh in patients after incisional hernia repair: initial results

The aim of our study was to develop a method that allows the vizualiation and evaluation of implanted mesh in patients after incisional hernia repair with MRI. Furthermore, we assessed problems typically related with mesh implantation like adhesions and muscular atrophy. We enrolled 28 patients after incisional hernia repair. In 10 patients mesh implantation was done by laparoscopy (expanded polytetrafluoroethylene=ePTFE mesh) and in 18 by laparotomy (polypropylene mesh). Functional MRI was performed on a 1.5-T system in supine position. Sagittal and axial TrueFISP images of the entire abdomen were acquired with the patient repeatedly straining. Evaluation included: correct position and intact fixation of the mesh, furthermore visceral adhesions, recurrent hernia and atrophy of the rectus muscle. The ePTFE mesh was visible in all cases; the polypropylene mesh was not detectable. In seven of the ten ePTFE meshes the fixation was not intact; two recurrent hernias were detected. Twenty of 28 patients had intraabdominal adhesions. In 5 cases mobility of the abdominal wall was reduced, and 16 patients showed an atropy of the rectus muscle. Functional cine MRI is a suitable method for follow-up studies in patients after hernia repair. ePTFE meshes can be visualized directly, and typical complications like intestinal adhesions and abdominal wall dysmotility can be assessed reliably.     

MRI在膝关节软骨病变中的应用及研究进展

膝关节是人体最大最复杂的关节,关节软骨在维持关节正常活动中起到重要作用。关节软骨病变是影响膝关节稳定性的重要因素。磁共振成像（magnetic resonance imaging,MRI）对诊断膝关节软骨病变具有良好的空间分辨率和组织对比度,是目前评价关节软骨病变最有效的无创技术,其在膝关节疾病诊断中的应用日益广泛并显示出独特的优势。     

Rapid cine MRI of the human heart using reconstruction by estimation of lines and inhibition of fold-in.

A fast imaging method is described that yields an approximately six-fold acquisition time reduction relative to conventional techniques. The method involves: 1) acquisition of every sixth k-space line; 2) shifting of acquired k-space lines between odd and even frames; and 3) a single-frame correction image. Reconstruction is achieved by temporal interpolation for k-space lines not acquired combined with subtraction of stationary fold-in artifacts. Seven patients with heart disease and one volunteer were evaluated. SNR was measured in myocardium and the ventricular cavity for both the conventional and new technique. The method is best suited for fast imaging of moving objects confined to a small region within a larger stationary object, such as the heart within the thoracic cavity. It can be implemented in cine and functional imaging sequences and, in principle, in perfusion sequences.     

Assessment of colonic transit time using MRI: a feasibility study

The aim of this pilot study was to evaluate a new, non-invasive examination method using MRI for the quantification of the colonic transit time after oral administration of gadolinium-saline solution filled capsules. Healthy volunteers without previous or acute symptoms of gastrointestinal disorders were enrolled. After a 3-day diet for the standardization of gastrocolonic content the volunteers swallowed five Gd-DTPA/saline 0.9%-filledcapsules. Seven different concentrations of Gd-DTPA/saline 0.9% solution between 1:0 and 0:1 were tested in a dilution series. Following ingestion of capsules, coronal Flash T1 and True Fisp sequences using a 1.5 Tesla system were obtained at 0 h, 3 h, 6 h, 12 h, 24 h, 36 h and 60 h. Sequences were analyzed by two independent experts for locating the capsules. Overall colonic transit time was separately analyzed for both genders. Fifteen healthy volunteers (7 females, 8 males; mean age 34±13 years) were enrolled. The phantom study provided the best contrast in both the T1-and T2-weighted sequences defining a ratio of 1:10 for Gd-DTPA/saline 0.9% solution. The mean transit time accounted for 41±9 h in women and for 31±10 h in men. MRI is an adequate method for the assessment of colonic transit time offering the advantages of no exposure to radiation, short examination time, possible dynamic evaluation of the transit and the practicability in terms of a future adoption to clinical routine.     

Cine MR imaging before and after realignment surgery for patellar maltracking — comparison with axial radiographs

Objective Comparison of motion-triggered cine magnetic resonance (MR) imaging and conventional radiographs for the assessment of operative results of patellar realignment.Subjects and methods Fifteen patients with recurrent patellar dislocation or patellar subluxation were evaluated with conventional axial radiographs before and after realignment surgery by measuring the congruence angle (CA), lateral patellofemoral angle (LPFA), and lateral displacement (d). In eight patients the patellofemoral joint was additionally evaluated pre- and postoperatively with motion-triggered cine MR imaging by determining the bisect offset (BSO), lateral patellar displacement (LPD), and patellar tilt angle (PTA).Results and conclusions Significant differences between the pre- and postoperative measurements were found for all MR imaging parameters (BSO, LPD, PTA: p<0.01) but not for the conventional X-ray parameters (CA: p=0.70, LPFA: p=0.56; d: p=0.04). Motion-triggered cine MR imaging was superior to conventional tangential radiographs for assessing the effectiveness of patellar realignment surgery.     

MRI criteria for patella alta and baja

Objective To determine the range of the patellar tendon length to patellar length ratio on magnetic resonance imaging (MRI) of the knee in order to aid in the establishment of MRI criteria for patella alta and baja.Patients Two hundred and forty-five patients ages 6–85 (mean 44) years who went through 262 consecutive 1.5 MRI studies of the knee performed during November 2000 through February 2001 were evaluated, regardless of their clinical symptoms.Design Patellar length (PL) and patellar tendon length (TL) were measured by a single musculoskeletal radiologist on sagittal images by a line connecting the superior and inferior patellar poles and the shortest length of the inner margin of the tendon respectively. TL/PL ratio was subsequently calculated. The distribution of ratios was evaluated; the extreme 2.5% at each end of the distribution was defined as patella alta and baja.Results The TL/PL ratio ranged between 0.56 and 1.71 (mean 1.05). After plotting the ratios, we noted an asymmetric curve skewed to the left. Based upon calculation of the extreme 2.5% of the ratio at each end of the plot, we determined that the MRI definition of patella alta and baja is a ratio of TL/PL of more than 1.50 and less than 0.74 respectively. We found that females had significantly higher TL/PL ratio than males (1.0878 and 1.0032 respectively). Ratios defined for patella alta and baja were 1.52 and 0.79 respectively in females and 1.32 and 0.74 respectively in males (p<0.0001).Conclusion Patella alta and baja are determined as TL/PL of more than 1.50 and less than 0.74 respectively, somewhat different than traditionally quoted radiographic and previously described MRI criteria.     

痛风性膝关节炎MRI骨侵蚀、骨髓水肿、滑膜炎与痛风石的相关性研究

目的探讨膝关节痛风性关节炎MRI特征,及骨侵蚀、骨髓水肿、滑膜炎与痛风石之间的相互关系,以研究痛风骨侵蚀和关节损伤的潜在机制。方法回顾性分析31例慢性痛风患者膝关节双能量CT和MRI影像检查,对比分析痛风石、骨髓水肿、骨侵蚀及滑膜炎之间的相关关系。结果4例患者为双侧膝关节检查,共35个膝关节纳入研究,其中34%的存在骨侵蚀,与痛风石有明显相关性,OR值76.4(95%CI 10.0,582.2)(P<0.001)。骨髓水肿不常见,发生率仅为1.2%(3/245),骨侵蚀和骨髓水肿之间没有明显相关性。在有骨侵蚀的膝关节中,75%的膝关节同时伴有滑膜炎,而在没有骨侵蚀的膝关节,43.4%的膝关节具有滑膜炎,骨侵蚀和滑膜炎之间的OR值为5.3(95%CI 1.1,25.5)(P=0.035)。结论痛风性关节炎骨侵蚀,与痛风石沉积明显相关;痛风骨髓水肿不常见,且水肿程度轻微。痛风石是骨侵蚀发生的主要危险因素之一。     

膝关节交叉韧带低场强MRI表现及其损伤诊断

目的 :研究膝关节正常交叉韧带MRI特点和交叉韧带损伤的的MRI表现。方法 :对 2 0 0例正常膝关节交叉韧带的MRI进行回顾性分析 ,对 2 5例临床可疑交叉韧带损伤患者的MRI资料和关节镜检查行对比研究。结果 :正常膝关节矢状位MRI上显示交叉韧带最佳 ,冠状位和横断位作为补充 ,交叉韧带损伤的MRI表现为韧带连续性中断、局灶性或弥漫性肿胀、信号强度增高及断端移位 ;以关节镜检查结果为标准 ,MRI诊断交叉韧带损伤的敏感度为 91.3 % ,特异度为 91.6% ,符合率为 91.4%。结论 :MRI多方位扫描是一种准确诊断交叉韧带损伤的方法 ,矢状位显示交叉韧带最佳。     

膝关节创伤性积脂血症的MRI诊断

目的：探讨膝关节创伤性积脂血症的MRI影像学特点及诊断价值。方法：回顾性分析32例膝关节创伤性积脂血症患者的MRI影像学特征。所有患者于受伤后1h～6天内行MRI检查。结果：32例膝关节积脂血症患者关节囊（髌上囊）出现脂肪-血液界面征,均为单侧,左侧14例,右侧18例。单液-液平面的23例,双液-液平面9例,液-液平面最上层均为脂肪信号。结论：膝关节创伤性积脂血症在MRI上有特征性的影像学表现,可作为诊断关节囊内骨折的间接征象,MRI是诊断膝关节创伤性积脂血症最佳影像学方法。