Chondromalacia of the knee: Evaluation with a fat-suppression three-dimensional SPGR imaging after intravenous contrast injection

Twenty-one MRI studies with a fat-suppression three-dimensional spoiled gradient-recalled echo in a steady state (3D SPGR) pulse sequence after intravenous contrast injection were evaluated to assess the accuracy in depicting chondromalacia of the knee. On the basis of MR images, chondromalacia and its grade were determined in each of five articular cartilage regions (total, 105 regions) and then the results were compared to arthroscopic findings. The sensitivity, specificity, and accuracy of MRI were 70%, 99%, and 93%, respectively. MR images depicted 7 of 11 lesions of arthroscopic grade 1 or 2 chondromalacia, and seven of nine lesions of arthroscopic grade 3 or 4 chondromalacia. The cartilage abnormalities in all cases appeared as focal lesions with high signal intensity. Intravenous contrast-injection, fat-suppression 3D SPGR imaging showed high specificity in excluding cartilage abnormalities and may be considered as an alternative to intra-articular MR arthrography when chondromalacia is suspected.     

Qualitative and Quantitative Assessment of Isotropic Ankle Magnetic Resonance Imaging: Three-Dimensional Isotropic Intermediate-Weighted Turbo Spin Echo versus Three-Dimensional Isotropic Fast Field Echo Sequences

Objective

To compare the image quality of volume isotropic turbo spin echo acquisition (VISTA) imaging method with that of the three-dimensional (3D) isotropic fast field echo (FFE) imaging method applied for ankle joint imaging.

Materials and Methods

MR imaging of the ankles of 10 healthy volunteers was performed with VISTA and 3D FFE sequences by using a 3.0 T machine. Two radiologists retrospectively assessed the tissue contrast between fluid and cartilage (F-C), and fluid and the Achilles tendon (F-T) with use of a 4-point scale. For a quantitative analysis, signal-to-noise ratio (SNR) was obtained by imaging phantom, and the contrast ratios (CRs) were calculated between F-T and F-C. Statistical analyses for differences in grades of tissue contrast and CRs were performed.

Results

VISTA had significantly superior grades in tissue contrast of F-T (p = 0.001). Results of 3D FFE had superior grades in tissue contrast of F-C, but these result were not statistically significant (p = 0.157). VISTA had significantly superior CRs in F-T (p = 0.002), and 3D FFE had superior CRs in F-C (p = 0.003). The SNR of VISTA was higher than that of 3D FFE (49.24 vs. 15.94).

Conclusion

VISTA demonstrates superior tissue contrast between fluid and the Achiles tendon in terms of quantitative and qualitative analysis, while 3D FFE shows superior tissue contrast between fluid and cartilage in terms of quantitative analysis.     

Evaluation of grades 3 and 4 chondromalacia of the knee using T2*-weighted 3D gradient-echo articular cartilage imaging

Objective. To determine the accuracy of T2*-weighted three-dimensional (3D) gradient-echo articular cartilage imaging in the identification of grades 3 and 4 chondromalacia of the knee. Design and patients. A retrospective evaluation of 80 patients who underwent both arthroscopic and MRI evaluation was performed. The 3D images were interpreted by one observer without knowledge of the surgical results. The medial and lateral femoral condyles, the medial and lateral tibial plateau, the patellar cartilage and trochlear groove were evaluated. MR cartilage images were considered positive if focal reduction of cartilage thickness was present (grade 3 chondromalacia) or if complete loss of cartilage was present (grade 4 chondromalacia). Comparison of the 3D MR results with the arthroscopic findings was performed. Results. Eighty patients were included in the study group. A total of 480 articular cartilage sites were evaluated with MRI and arthroscopy. Results of MR identification of grades 3 and 4 chondromalacia, all sites combined, were: sensitivity 83%, specificity 97%, false negative rate 17%, false positive rate 3%, positive predictive value 87%, negative predictive value 95%, overall accuracy 93%. Conclusion. The results demonstrate that T2*-weighted 3D gradient-echo articular cartilage imaging can identify grades 3 and 4 chondromalacia of the knee. Received: 18 April 2000 Revision requested: 18 July 2000 Revision received: 10 October 2000 Accepted: 27 November 2000     

Gossypiboma of the Leg: MR Imaging Characteristics. A Case Report

We report a 22-year-old man with a solid mass in the right proximal leg, which was furned out to be a gossypiboma. MR imaging revealed a well-defined mass lesion that showed intermediate signal intensity at T1-weighted imaging (T1WI) and slightly high signal intensity at T2-weighted imaging (T2WI). Wavy, low-signal-intensity stripes were visible within the fluid-filled central cavity. At surgical exploration, a sponge, retained after previous knee surgery, was discovered, and it was found that a granuloma had developed. Pathologic examination revealed granulomatous inflammation, with lymphocyte and giant cell infiltration. The presence of wavy, low-signal-intensity gauze fibers at T2WI may be a characteristic MR appearance of gossypiboma.     

Magnetic resonance imaging of cartilage and cartilage repair

Magnetic resonance (MR) imaging of articular cartilage has assumed increased importance because of the prevalence of cartilage injury and degeneration, as well as the development of new surgical and pharmacological techniques to treat damaged cartilage. This article will review relevant aspects of the structure and biochemistry of cartilage that are important for understanding MR imaging of cartilage, describe optimal MR pulse sequences for its evaluation, and review the role of experimental quantitative MR techniques. These MR aspects are applied to clinical scenarios, including traumatic chondral injury, osteoarthritis, inflammatory arthritis, and cartilage repair procedures.     

膝关节半月板损伤的磁共振诊断:三维质子加权序列与二维序列的对比

目的 比较评估三维快速自旋回波(3D-SPACE)序列与传统二维快速自旋回波(2D-TSE)序列对于膝关节半月板损伤的诊断价值.方法 半月板撕裂病例共40例.对所有患者进行3D-SPACE序列及2D序列的扫描,根据所得图像对半月板撕裂进行分型诊断.分别计算半月板信噪比(SNR)、半月板/软骨对比噪声比(CNR)、半月板/韧带CNR、半月板/关节液CNR,比较两者是否有统计学差异;与关节镜或手术结果比较,计算诊断半月板撕裂的敏感度、特异度、阳性预测值、阴性预测值及准确率,比较两者诊断符合率是否有统计学差异.结果 3D序列对于复合撕裂的诊断准确率较高.两种序列所得图像半月板SNR间差异无统计学意义(P=0.736);两种序列所得图像半月板/软骨CNR差异无统计学意义(P=0.526),半月板/韧带CNR差异有统计学意义(P=0.029),半月板/关节液CNR差异无统计学意义(P=0.899).3D-PD-SPACE序列采集所得图像Kappa值为0.84,表示不同观察者之间具有较强的一致性.两种序列在诊断半月板撕裂的准确性上没有明显差异(P=0.576 ＞0.05).结论 3D-SPACE序列是一种新的MR成像序列,能进行各向同性的扫描及多平面薄层重组,对于某些半月板撕裂类型诊断准确性较高,在膝关节半月板损伤的诊断方面有潜在应用价值.     

Comparison of Three-Dimensional Isotropic and Two-Dimensional Conventional Indirect MR Arthrography for the Diagnosis of Rotator Cuff Tears

Objective

To compare the accuracy between a three-dimensional (3D) indirect isotropic T1-weighted fast spin-echo (FSE) magnetic resonance (MR) arthrography and a conventional two-dimensional (2D) T1-weighted sequences of indirect MR arthrography for diagnosing rotator cuff tears.

Materials and Methods

The study was approved by our Institutional Review Board. In total, 205 patients who had undergone indirect shoulder MR arthrography followed by arthroscopic surgery for 206 shoulders were included in this study. Both conventional 2D T1-weighted FSE sequences and 3D isotropic T1-weighted FSE sequence were performed in all patients. Two radiologists evaluated the images for the presence of full- or partial-thickness tears in the supraspinatus-infraspinatus (SSP-ISP) tendons and tears in the subscapularis (SSC) tendons. Using the arthroscopic findings as the reference standard, the diagnostic performances of both methods were analyzed by the area under the receiver operating characteristic curve (AUC).

Results

Arthroscopy confirmed 165 SSP-ISP tendon tears and 103 SSC tendon tears. For diagnosing SSP-ISP tendon tears, the AUC values were 0.964 and 0.989 for the 2D sequences and 3D T1-weighted FSE sequence, respectively, in reader I and 0.947 and 0.963, respectively, in reader II. The AUC values for diagnosing SSC tendon tears were 0.921 and 0.925, respectively, for reader I and 0.856 and 0.860, respectively, for reader II. There was no significant difference between the AUC values of the 2D and 3D sequences in either reader for either type of tear.

Conclusion

3D indirect isotropic MR arthrography with FSE sequence and the conventional 2D arthrography are not significantly different in terms of accuracy for diagnosing rotator cuff tears.     

Magnetic resonance imaging of the hip with a pelvic phased-array surface coil: a technical note

Objective. The aim of this study was to assess the capability of high-resolution images obtained with a commercially available pelvic phased-array surface coil to demonstrate normal hip anatomy. Design. We retrospectively analyzed the oblique coronal magnetic resonance (MR) images of hips of 36 consecutive patients acquired on a 1.5-T clinical imager using a pelvic phased-array coil as a receiver, a 16–20 cm field of view, and 5 mm slice thickness. Patients. Thirty-six patients were studied, age 15–81 years. There were 20 males and 16 females. Results and conclusions. The articular cartilage, cortex, superior labrum, and iliofemoral ligament were well visualized on proton density weighted fat saturation (PDF) images. The femoral and obturator vessels, obturator nerve, and various muscles were easily seen on T1-weighted images. High-resolution imaging of the hip is achievable in a reasonable amount of time using newer phased-array surface coils and may play an increasing role in the future evaluation of hip disorders.     

Accuracy of Preoperative MRI with Microscopy Coil in Evaluation of Primary Tumor Thickness of Malignant Melanoma of the Skin with Histopathologic Correlation

Objective

The purpose of this study was to evaluate the accuracy of a preoperative MRI with microscopy coils in determining the primary tumor thickness of malignant melanoma with histopathologic correlation.

Materials and Methods

Eleven patients with histopathologically confirmed malignant melanoma were included in this study. MR images of the tumors were obtained with a 47-mm microscopy coil on 1.5T MR scanners and were evaluated by two radiologists, who assessed the thickness of the primary tumor on T2-weighted images (T2WI) and gadolinium-enhanced T1-weighted images with fat suppression (Gd-T1WI) and compared the results with the histopathologic findings as the reference standard. Correlations between tumor thickness on MRI and histopathologic examination were assessed using concordance correlation coefficients (CCCs). Inter- and intraobserver variabilities of tumor measurements were also assessed by intraclass correlation coefficient (ICC).

Results

Among the 11 cases included in the study, 10 cases from the same number of patients were managed with surgical excision and one case was confirmed with punch biopsy. The primary tumor thickness measured on T2WI showed better correlation with histopathologic results, as compared with measurements taken on Gd-T1WI: the CCC of measurements on T2WI ranged from 0.64 to 0.78, indicating a substantial agreement, whereas the CCC of measurements on Gd-T1WI ranged from 0.50 to 0.61, indicating a moderate to substantial agreement. Inter- and intraobserver agreements of readers 1 and 2 were excellent for both T2WI and Gd-T1WI, with ICC ranging from 0.86 to 0.99.

Conclusion

MR imaging with microscopy coils may be an accurate technique in the preoperative assessment of tumor thickness in malignant melanoma, especially on T2-weighted images.     

Evaluation of the iliac arteries: Comparison of two-dimensional time of flight magnetic resonance angiography with cardiac compensated fast gradient recalled echo and contrast-enhanced three-dimensional time of flight magnetic resonance angiography

We compared dynamic contrast-enhanced three-dimensional time of flight (3DTOF) magnetic resonance angiography (MRA) with two-dimensional time of flight (2DTOF) MRA with cardiac compensated fast gradient recalled echo (C-MON) and conventional angiography (CA) when it was available. C-MON re-orders the normal data acquisition to minimize ghosting artifacts generated by pulsatile flow. The initial phase of the study involved optimization of parameters and comparison C-MON with no C=MON in eight patients and volunteers. The final phase of the study involved 53 patients who were imaged with contrast-enhanced 3DTOF MRA and 2DTOF MRA with C-MON. Thirty of these patients also had CA. In the initial phase, 2DTOF MRA with C-MON was found to be equal (n = 3) or superior (n = 5) to 2DTOF without C-MON. In the final phase, the agreement among all imaging modalities varied from substantial to almost perfect (Cohen's _K = .6-.83). The lowest agreement was using 2DTOF to evaluate the external iliac segments. The among suggested treatments varied from substantial to almost perfect for all imaging modalities (Cohen's _K = .73–93). The diagnostic efficacies of 2DTOF with C-MON and contrast-enhanced 3DTOF were high overall, with the lowest value being a specificity of 63% for one reader in the evaluation of an external iliac segment using 2DTOF. In summary, 2DTOF with C-MON helped to eliminate artifacts due to pulsatility in the iliac arterial segments. In our experience, both dynamic constrast-enhanced 3DTOF MRA and 2DTOF MRA with C-MON performed well in the evaluation of the iliac arteries. Both studies have high interobserver agreement and high diagnostic efficacy. Contrast-enhanced 3DTOF MRA should be reserved for situations in which the iliac vessels are extremely tortuous or occluded or the external iliac segments are poorly seen.     

EPI在上腹部MR成像中的应用:结果与屏气FSE T_2加权像比较

目的：比较８个发射的平面回波成像（ＥＰＩ）与屏气快速自旋回波（ＦＳＥ）对上腹部的Ｔ２ 加权ＭＲ成像。方法：对１７名志愿者,进行了上腹部８ 个发射的ＥＰＩ（１８ｓ）,结果与屏气ＦＳＥＴ２ 加权像（２４ｓ）比较。脂肪抑制技术被应用于每个序列。对肝脏、脾、胰腺和肾脏的信噪比（ＳＮＲ）和脾－ 肝信号强度差别与噪音比率（ＳＤ／Ｎｓ）,以及对显示上腹部器官能力和图像质量进行质量评定。结果：８ 个发射的ＥＰＩ比屏气的ＦＳＥＴ２ 加权像在肝脏（４．６５±１．７５ Ｖｓ ３．１２±１．１５,ｐ＜ ０．０１）,脾脏（８．８６±３．１２ Ｖｓ ６．９１±１．９８,ｐ＜０．０５）和胰腺（５．３９±１．９５Ｖｓ３．３６±１．１９,ｐ＜ ０．００５）ＳＮＲ均有显著增加,但对肾脏ＳＮＲ的增加（８．１４±３．００ Ｖｓ７．３１±２．４３,ｐ＝ ０．３９６５）不明显。两者显示的脾－ 肝ＳＤ／Ｎｓ基本相似（４．２１±１．９７ Ｖｓ３．７９±１．０７,ｐ＝ ０．４６１９）。对显示上腹部器官影像的质量,８个发射的ＥＰＩ比屏气ＦＳＥＴ２ 加权像好,且没有明显的呼吸运动伪影,但前者比后者具有更多的来自于胃肠气体的磁敏感性伪影。结论：上腹部的ＭＲ成像,８ 个发射的ＥＰＩ能     

Functional MR Imaging of Psychogenic Amnesia: A Case Report

We present here a case in which functional MR imaging (fMRI) was done for a patient who developed retrograde psychogenic amnesia for a four year period of her life history after a severe stressful event. We performed the fMRI study for a face recognition task using stimulation with three kinds of face photographs: recognizable familiar faces, unrecognizable friends'' faces due to the psychogenic amnesia, and unfamiliar control faces. Different activation patterns between the recognizable faces and unrecognizable faces were found in the limbic area, and especially in the amygdala and hippocampus.     

前列腺和精囊磁共振扩散成像中EPI与SSFSE序列的比较

目的比较回波平面成像（EPI）与单次激发快速自旋回波（SSFSE）扩散成像序列测量前列腺和精囊的表观扩散系数（ADC）值. 资料与方法选择40例无前列腺和精囊疾病的男性,使用EPI和SSFSE扩散成像序列,行前列腺和精囊局部的磁共振扩散成像检查.两种脉冲序列的扩散敏感梯度（b）值均取1 000s/mm2.在工作站上测量前列腺中央带和外周带、精囊、膀胱、盆腔脂肪、直肠内气体的ADC值.对两种脉冲序列测得的组织ADC值使用配对t检验进行比较. 结果 EPI序列40名受检者中32例（80%）获得可测量ADC值的图像,SSFSE序列40例（100%）获得可测量ADC值的图像.两种扩散成像序列测得的膀胱、直肠内气体和盆腔脂肪的ADC值无统计学差异（P〉0.05）,而两种扩散成像序列测得的前列腺中央带、外周带、精囊的ADC值有统计学差异（P〈0.01）.EPI序列测得上述组织的ADC值较小. 结论不同扩散成像序列测得的前列腺中央带、外周带和精囊的ADC值有差异.     

Contour irregularities of the distal femur caused by developmental, traumatic, and benign cortically-based neoplastic conditions: radiographic and MRI correlation

This review illustrates the radiographic and magnetic resonance imaging (MRI) appearances of a variety of entities that result in surface contour abnormalities of the distal femur. Such abnormalities may result from developmental variants expressed in the growing skeleton, from trauma, or from cortically-based tumours. As the number of MRI examinations of the knee performed annually to exclude internal derangement increases, the frequency with which these variants and pathological entities are encountered will likewise increase. In most cases, the location of the lesion, as well as its specific imaging characteristics, will allow an accurate diagnosis.     

Assessment of normal patellar cartilage volume and thickness using MRI: an analysis of currently available pulse sequences

 Objective. The objective of this study was to analyse the potential of magnetic resonance imaging for valid determination of patellar cartilage thickness, comparing currently available pulse sequences. Design. In six patients and one cadaver the cartilage was repetitively imaged employing three spin-echo and six three-dimensional gradient-echo sequences. In the cadaveric specimen the total volume and the regional distribution of cartilage thickness were assessed and compared with the values obtained from anatomical sections by image analysis. Results and conclusions. The FLASH and fat-suppressed FLASH sequences allowed the most accurate determination of the cartilage volume and thickness. Fat-suppression considerably increased the contrast of the cartilage to the synovial fluid, fat and bone marrow, yielding higher reproducibility of the volumetric measurements. The remaining difference from the anatomical volume and thickness may be because the calcified cartilage is not delineated by magnetic resonance imaging.     

Magnetization transfer analysis of cartilage repair tissue: a preliminary study

Purpose To evaluate the magnetization transfer ratio (MTR) after two different cartilage repair procedures, and to compare these data with the MTR of normal cartilage.Design and patients Twenty-seven patients with a proven cartilage defect were recruited: 13 were treated with autologous chondrocyte implantation (ACI) and 14 were treated with the microfracture technique (MFR). All patients underwent MRI examinations with MT-sequences before the surgical treatment, after 12 months (26 patients) and after 24 months (11 patients). Eleven patients received a complete follow-up study at all three time points (five of the ACI group and six of the MFR group). All images were transferred to a workstation to calculate MTR images. For every MT image set, different ROIs were delineated by two radiologists. Means were calculated per ROI type in the different time frames and in both groups of cartilage repair. The data were analyzed with unpaired t- and ANOVA tests, and by calculating Pearson’s correlation coefficient.Results No significant differences were found in the MTR of fatty bone marrow, muscle and normal cartilage in the different time frames. There was a significant but small difference between the MTR of normal cartilage and the cartilage repair area after 12 months for both procedures. After 24 months, the MTR of ACI repaired cartilage (0.31±0.07) was not significantly different from normal cartilage MTR (0.34±0.05). The MTR of MFR repaired cartilage (0.28±0.02), still showed a significant difference from normal cartilage.Conclusion The differences between damaged and repaired cartilage MTR are too small to enable MT-imaging to be a useful tool for postoperative follow-up of cartilage repair procedures. There is, however, an evolution towards normal MTR-values in the cartilage repair tissue (especially after ACI repair).     

Virtual MR arthroscopy of the wrist joint: a new intraarticular perspective

Objective The aim of this study is to investigate whether virtual MR arthroscopy could be used to visualize the internal architecture of the radiocarpal compartment of the wrist joint in comparison to surgical arthroscopy.Design Diluted paramagnetic contrast material was injected into the radiocarpal compartment prior to MR examination in all patients. A fat-suppressed T1-weighted three-dimensional fast spoiled gradient echo sequence was acquired in addition to our standard MR imaging protocol in each patient. Three-dimensional data sets were then transferred to an independent workstation and were postprocessed using navigator software to generate surface rendered virtual MR arthroscopic images.Patients Nineteen patients referred for chronic ulnar-sided wrist pain were evaluated with conventional MR arthrography prospectively.Results and Conclusion Virtual MR arthroscopic images demonstrating the triangular fibrocartilage complex (TFCC) in an intraarticular perspective were achieved in 12 out of 19 patients. Our preliminary investigation suggests that although it has several limitations, virtual MR arthroscopy shows promise in visualizing the TFCC from an intraarticular perspective.     

MR imaging of hyaline cartilage at 0.5 T: a quantitative and qualitative in vitro evaluation of three types of sequences

Objective. To identify an optimal pulse sequence for in vitro imaging of hyaline cartilage at 0.5 T. Materials and methods. Twelve holes of varying diameter and depth were drilled in cartilage of two pig knees. These were submerged in saline and scanned with a 0.5-T MR system. Sixteen T1-weighted gradient echo (GE), two T2-weighted GE, and 16 fast spin echo sequences were used, by varying repetition time (TR), echo time (TE), flip angle (FA), echo train length, profile order, and by use of fat saturation. Contrast-to-noise ratios (CNR) of cartilage versus saline solution and cartilage versus subchondral bone were measured. Cartilaginous lesions were evaluated separately by three independent observers. Interobserver variability and correlation between the quantitative and qualitative analyses were calculated. Results. The mean CNRs of two specimens of cartilage versus saline solution ranged from 6.3 (±2.1) to 27.7 (±2.5), and those of cartilage versus subchondral bone from 0.3 (±0.2) to 22.5 (±1.4). The highest CNR was obtained with a T1-weighted spoiled 3D-GE technique (TR 65 ms, TE 11.5 ms, FA 45°). The number of lesions observed per sequence varied from 35 to 69. Observer agreement was fair to good. The T1-weighted spoiled GE sequences with a TR of 65 ms, TE of 11.5 ms and FA of 30° and 45° were significantly superior to the other 34 sequences in the qualitative analysis. Conclusion. T1-weighted spoiled 3D-GE sequences with a TR of 65 ms, a TE of 11.5 ms, and a FA of 30–45° were found to be optimal for in vitro imaging of cartilage at 0.5 T.     

Experimental model to evaluate in vivo and in vitro cartilage MR imaging by means of histological analyses

Objectives

Implementation of an experimental model to compare cartilage MR imaging by means of histological analyses.

Material and methods

MRI was obtained from 4 patients expecting total knee replacement at 1.5 and/or 3 T prior surgery. The timeframe between pre-op MRI and knee replacement was within two days. Resected cartilage-bone samples were tagged with Ethi^®-pins to reproduce the histological cutting course. Pre-operative scanning at 1.5 T included following parameters for fast low angle shot (FLASH: TR/TE/FA = 33 ms/6 ms/30°, BW = 110 kHz, 120 mm × 120 mm FOV, 256 × 256 matrix, 0.65 mm slice-thickness) and double echo steady state (DESS: TR/TE/FA = 23.7 ms/6.9 ms/40°, BW = 130 kHz, 120 × 120 mm FOV, 256 × 256 matrix, 0.65 mm slice-thickness). At 3 T, scan parameters were: FLASH (TR/TE/FA = 12.2 ms/5.1 ms/10°, BW = 130 kHz, 170 × 170 mm FOV, 320 × 320, 0.5 mm slice-thickness) and DESS (TR/TE/FA = 15.6 ms/4.5 ms/25°, BW = 200 kHz, 135 mm × 150 mm FOV, 288 × 320 matrix, 0.5 mm slice-thickness). Imaging of the specimens was done the same day at 1.5 T. MRI (Noyes) and histological (Mankin) score scales were correlated using the paired t-test. Sensitivity and specificity for the detection of different grades of cartilage degeneration were assessed. Inter-reader and intra-reader reliability was determined using Kappa analysis.

Results

Low correlation (sensitivity, specificity) was found for both sequences in normal to mild Mankin grades. Only moderate to severe changes were diagnosed with higher significance and specificity. The use of higher field-strengths was advantageous for both protocols with sensitivity values ranging from 13.6% to 93.3% (FLASH) and 20.5% to 96.2% (DESS). Kappa values ranged from 0.488 to 0.944.

Conclusions

Correlating MR images with continuous histological slices was feasible by using three-dimensional imaging, multi-planar-reformat and marker pins. The capability of diagnosing early cartilage changes with high accuracy could not be proven for both FLASH and DESS.     

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。