肾脏肿瘤的MR动态增强扫描研究

目的:探讨MR动态增强扫描在肾脏肿瘤诊断和鉴别诊断中的价值。方法:对21例肾细胞癌、11例肾错构瘤和6例肾囊肿行MR常规检查及动态增强和延迟增强扫描,测量病灶的信号强度,绘制时间-对比增强率曲线并对动态增强的类型及血液动力学改变进行分析。结果:肾脏肿瘤动态增强后的时间-对比增强率曲线不同,富血供肾癌在早期强化并逐渐上升,但其时间-对比增强率曲线无明显峰值;乏血供肾癌早期轻度强化,缓慢上升至60s后趋于稳定;肾错构瘤早期即明显强化,于30s达到强化高峰后快速下降;肾囊肿则无明显强化。结论:通过定量分析肾脏肿瘤的信号强度,动态增强MRI可以提供肿瘤的血供信息,有助于肾脏肿瘤的诊断和鉴别诊断。     

Non-mass-like enhancement on contrast-enhanced breast MR imaging: Lesion characterization using combination of dynamic contrast-enhanced and diffusion-weighted MR images

Purpose

To evaluate the diagnostic accuracy of a combination of dynamic contrast-enhanced MR imaging (DCE-MRI) and diffusion-weighted MR imaging (DWI) in characterization of lesions showing non-mass-like enhancement on breast MR imaging and to find the strongest discriminators between carcinoma and benignancy.

Materials and methods

We analyzed consecutive MR images in 45 lesions showing non-mass like enhancement in 41 patients. We analyzed lesion size, distribution, internal enhancement, kinetic curve pattern, and apparent diffusion coefficient (ADC) values. We applied univariate and multivariate analyses to find the strongest indicators for malignancy. In a validation study, 22 non-mass-like enhancement lesions in 21 patients were examined. We calculated diagnostic accuracy when we presume category 4b, 4c, and 5 lesions as malignant or high to moderate suspicion for malignancy, and category 4a and 3 as low suspicion for malignancy or benign.

Results

Segmental distribution (P = 0.018), clumped internal enhancement (P = 0.005), and ADC less than 1.3 × 10⁻³ mm²/s (P = 0.047) were the strongest MR indicators of malignancy. In a validation study, sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 87% (13/15), 86% (6/7), 93% (13/14), 75% (6/8) and 86% (19/22), respectively.

Conclusion

The combination of DCE-MRI and DWI showed high diagnostic accuracy in characterization of non-mass-like enhancement lesions on breast MR images.     

三维对比剂增强MR门静脉成像与直接门静脉造影术对照

目的通过与直接门静脉造影术的比较，评价三维对比剂增强MR门静脉成像（3D CE MRP）的准确性。方法26例患者行3D CE MRP和直接门静脉造影检查。分析3D CE MRP上门静脉主干、肝内左右分支的开放性和侧支循环发生情况，其结果与直接门静脉造影对照，评价两者符合情况，并分析两者不符的原因。结果3D CE MRP和直接门静脉造影显示门静脉主干的结果完全一致。对肝内门静脉分支，有21例2种检查结果符合，但有5例不符。1例肝右叶巨大肿瘤，3D CE MRP显示门静脉右后支闭塞，但直接门静脉造影显示明显狭窄。3例左叶肝癌患者，3D CE MRP显示门静脉左支闭塞，但直接门静脉造影显示其近段狭窄和远端闭塞。另有1例肝癌患者，3D CE MRP显示门静脉左支矢状段小癌栓，而直接门静脉造影却未能显示。除1例脐静脉重开由于扫描范围较小未显示之外，3D CE MRP显示侧支循环的结果和直接门静脉造影相符。结论多数病例，3D CE MRP的显示结果与直接门静脉造影符合。3D CE MRP在鉴别肝内门静脉分支狭窄或闭塞时有一定限度，而在显示门静脉小栓子方面却有优势。     

3D contrast-enhanced MR portography and direct X-ray portography: a correlation study

Our objective was to compare 3D contrast-enhanced MR portography (3D CE MRP) on a 1.5-T MR imager with direct X-ray portography. Twenty-six consecutive patients underwent 3D CE MRP with in-plane resolution of 1.4 or 1.8 mm, and direct X-ray portography. The findings of these two methods were evaluated and compared. The main portal vein (PV), right PV with its anterior and posterior segmental branches, and left PV including its sagittal segment were shown clearly without diagnostic problem in all cases on MRP. The main PV appearance was accordant with MRP and X-ray. For intrahepatic PVs, the results agreed in 21 patients but disagreed in 5 patients. In 1 patient with a huge tumor in right liver, the right posterior PV was classified as occluded at MRP, but diffusely narrowed at X-ray. The findings of left intrahepatic PV were discordant in 3 patients with hepatocelluar carcinoma in the left lobe. The MRP demonstrated complete occlusion of the left PVs, whereas X-ray showed proximal narrowing and distal occlusion. In another patient with hepatocelluar carcinoma, a small non-occlusive thrombus involving the sagittal segment of the left PV was seen on MRP but not on X-ray. With demonstration of varices and portosystemic shunts, MRP showed results similar to those of X-ray, except one recanalized para-umbilical vein was excluded from the field of view at MRP due to the patient's limited ability of breathholding. The 3D CE MRP correlated well with direct X-ray portography in most cases, it was limited in distinguishing narrowing of an intrahepatic PV from occlusion, but it showed advantage in demonstrating small thrombus within PV. Electronic Publication     

Quantitative dynamic contrast-enhanced MR imaging analysis of complex adnexal masses: a preliminary study

Objective  

To evaluate the ability of quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to differentiate malignant from benign adnexal tumours.     

定量动态对比增强MRI分析复杂性附件肿块:初步研究

目的评价定量动态对比增强MRI(DCE-MRI)鉴别附件良恶性肿瘤的能力。方法56例患有复杂性附件肿块的妇女于术前行MR成像,其中38例恶性和18例良性。于附件肿瘤的实性组织应用药物代谢动力学模型,从高时间分辨力DCE-MRI序列中获取微血管参数。这些参数是组织血     

急性、亚急性和慢性心肌梗死:2D和3D延迟钆增强MR成像的定量对比研究

目的对比评估延迟钆增强(LGE)单次屏气三维(3D)反转恢复MR序列和临床常用的二维(2D)序列在定量分析心肌瘢痕质量与透壁程度的作用。材料与方法所有参加本研究的病人均签署知情同意书,本研究经机构伦理委员     

Cervical spondylosis: contrast-enhanced magnetization transfer prepulsed 3D turbo field echo MR imaging

Magnetic resonance (MR) imaging of the cervical spine with axial, low flip angle three-dimensional (3D) gradient-echo sequences is limited by long acquisition times and also by increased sensitivity to extrinsic and intrinsic magnetic field inhomogeneity, magnetic susceptibility differences, chemical shifts, and cerebrospinal fluid pulsatility. We attempted to assess the performance of gadolinium-enhanced, magnetization transfer (MT) prepulsed 3D fast gradient-echo sequences in demonstrating spondylotic changes of the cervical spine. Twenty patients with known cervical spine spondylosis were prospectively imaged in the axial plane using two gradient-echo-based MR techniques: 3D fast field echo (FFE) and gadolinium-enhanced, MT prepulsed, segmented turbo field echo (TFE). An average of 58 neural foramina on the 3D FFE images and 47 neural foramina on the contrast-enhanced TFE images were judged to be narrowed. The degree of neural foraminal narrowing was significantly less on the contrast-enhanced TFE images compared with the FFE images (P <0.001). Contrast-enhanced, MT prepulsed, segmented 3D TFE MR imaging has potential for ameliorating some of the limitations encountered in the more widely used gradient-echo techniques.     

肺栓塞的MR成像:对比增强3DMR肺血管成像,对比增强低翻转角3DGRE序列和非增强自由诱发FISP序列的诊断准确性

目的分别应用标准团注-触发呼吸门控对比增强MR肺血管成像、对比增强重复循环相位呼吸门控低翻转角三维(3D)梯度回波(GRE)序列、平扫自由诱发心脏-呼吸门控真稳态快速进动(FISP)MR序列来评价肺动脉栓塞(PE)相关性表现。材料与方法此项研究遵从HIPAA并且经机构审查委员会批准。22例经CTA诊断PE的病人在CT检查后     

肥厚性心肌病:对比剂增强心血管MRI延迟强化定量分析

目的确定重复性最好的半自动灰阶阈值技术对大样本肥厚性心肌病(HCM)病人钆延迟强化(LGE)的定量。材料与方法研究由参与机构的内部审查委员会核准,所有     

Renal masses: quantitative assessment of enhancement with dynamic MR imaging

PURPOSE: To establish a quantitative magnetic resonance (MR) imaging contrast enhancement criterion for distinguishing cysts from solid renal lesions. MATERIALS AND METHODS: Regions of interest were measured in 74 patients with renal lesions evaluated by means of dynamic contrast material-enhanced MR imaging with serial breath-hold spoiled gradient-echo acquisitions. Sensitivity for renal tumors and specificity for renal cysts were established by using percentage of enhancement thresholds that varied between 5% and 35%. RESULTS: The mean percentage of enhancement at MR imaging for the 50 renal cysts was less than 5%; for the 50 renal tumors, it was 97% or higher. With use of a threshold percentage of enhancement of 15% and results obtained between 2 and 4 minutes after administration of contrast material, all malignancies (sensitivity for tumor, 100%) were diagnosed, and there were 6% or fewer false-positive tumor diagnoses. Lower thresholds resulted in unacceptably high false-positive rates (ie, cysts that appeared to enhance-pseudoenhancement), whereas higher threshold values (>20%) resulted in an unacceptably lower sensitivity for tumors. CONCLUSION: The optimal percentage of enhancement threshold for distinguishing cysts from malignancies with the imaging technique prescribed was 15%, and the optimal timing for measurement was 2-4 minutes after administration of contrast material.     

MR imaging of the intervertebral disc: a quantitative study

The T1 and T2 relaxation times and the proton density of the nucleus pulposus have been measured in 107 normal and 18 surgically proven degenerate intervertebral discs. Data from total saturation recovery and spin echo sequences have been utilised in a robust multi-point method and relaxation times and proton density calculated. The results show that both the T1 and T2 values of the normal nucleus pulposus decrease with age. There was no significant correlation between proton density and age in normal discs. At all ages there was a highly significant difference between the T1 values of normal and degenerate discs. With T2 a highly significant difference in the younger age groups reduced to no distinction in the seventh decade. The observed change in the T1 and T2 values of the nucleus is in agreement with the reduction of water content known to occur with age. Our results indicate that quantitative MR imaging may assist in the diagnosis of intervertebral disc degeneration.     

Dynamic enhancement features of cavernous sinus cavernous hemangiomas on conventional contrast-enhanced MR imaging

BACKGROUND AND PURPOSE: The reported MR imaging characteristics of cavernous sinus cavernous hemangiomas (CSCHs) in the literature are nonspecific. The purpose of our study was to explore dynamic enhancement features of CSCHs on conventional contrast-enhanced MR imaging and to correlate these features with histopathologic subtypes.MATERIALS AND METHODS: Twenty-one patients (8 male and 13 female; age range, 13–63 years; average age, 42.6 years) with surgically confirmed CSCHs were retrospectively investigated. Preoperative MR study was performed in all cases, consisting of T1-weighted axial imaging, T2-weighted axial imaging, T1-weighted sagittal imaging, and contrast-enhanced T1-weighted axial, sagittal, and coronal images.RESULTS: There were 4.8% (1/21) that showed homogeneous enhancement on all 3 contrast-enhanced sequences, whereas 95.2% (20/21) demonstrated heterogeneous enhancement on the first contrast-enhanced sequence. Among the 20 lesions, on subsequent contrast-enhanced sequences, 55.0% (11/20) showed homogeneous enhancement, whereas 35.0% (7/20) of lesions showed progressive contrast “filling in.” The remaining 10% (2/20) exhibited no apparent enhancement changes. The 95.2% (20/21) of lesions with heterogeneous enhancement on the first contrast-enhanced sequence correlated with type B or type C pathologic findings, whereas 4.8% (1/21) with homogeneous enhancement correlated with type A pathologic findings. Among the 20 type B or type C lesions, 80% (16/20) achieved total or near-total resection.CONCLUSION: Progressive contrast “filling in” in the tumors on conventional contrast-enhanced MR images can aid in differentiating between cavernous sinus lesions and suggest the diagnosis of cavernous hemangiomas.

Cavernous sinus cavernous hemangiomas (CSCHs) are rare vascular malformations, accounting for less than 1% of all parasellar masses.^1,2 Because of their tendency to bleed profusely during surgery, CSCHs require a different surgical approach and technique.^3–5 However, the rate of misdiagnosis is as high as 38.9%.⁶ Although the primary diagnostic tool for CSCHs is MR imaging, there are only scattered reports on their MR characteristics in the literature. The value of these reported MR characteristics is limited in diagnosis and differential diagnosis. However, as a specific characteristic of cavernous hemangiomas in extracranial organs, contrast “filling in” with CSCHs on dynamic MR imaging or CT has not been studied up to now. Our paper is a retrospective review of 21 patients with CSCHs surgically treated at our institution from 2001 through 2007, with particular focus on exploring new MR diagnostic characteristics for this lesion.     

Inflammation in carotid atherosclerotic plaque: a dynamic contrast-enhanced MR imaging study

PURPOSE: To prospectively evaluate if there is an association between plaque enhancement at magnetic resonance (MR) imaging and proinflammatory cardiovascular risk factors and plaque content. MATERIALS AND METHODS: This study was performed with informed consent, HIPAA compliance, and institutional review board approval. Contrast agent dynamics within carotid plaques were measured in 30 patients (29 men, one woman; mean age, 67.7 years +/- 10.7 [standard deviation]) who were scheduled to undergo carotid endarterectomy. Measurements were based on kinetic modeling of images obtained at 15-second intervals during which a gadolinium-based contrast agent was injected. The time-varying signal intensities within the plaques were used to estimate the fractional plasma volume (vp) and transfer constant (Ktrans) of contrast material into the extracellular space. Pearson correlation coefficients were computed between blinded MR measurements and histologic measurements of plaque composition, including macrophages, neovasculature, necrotic core, calcification, loose matrix, and dense fibrous tissue. Correlation coefficients or mean differences were computed regarding clinical markers of cardiovascular risk. RESULTS: Analyzable MR images and histologic results were obtained in 27 patients. Measurements of Ktrans correlated with macrophage (r = 0.75, P < .001), neovasculature (r = 0.71, P < .001), and loose matrix (r = 0.50, P = .01) content. Measurements of v(p) correlated with macrophage (r = 0.54, P = .004), neovasculature (r = 0.68, P < .001), and loose matrix (r = 0.42, P = .03) content. For clinical parameters, significant associations were correlated with Ktrans only, with decreased high-density lipoprotein levels (r = -0.66, P < .001) and elevated Ktrans measurements in smokers compared with nonsmokers (mean, 0.134 min(-1) vs 0.074 min(-1), respectively; P = .01). CONCLUSION: The correlations between Ktrans and histologic markers of inflammation suggest that Ktrans is a quantitative and noninvasive marker of plaque inflammation, which is further supported by the correlation of Ktrans with proinflammatory cardiovascular risk factors, decreased high-density lipoprotein levels, and smoking.     

Scrotal disorders: evaluation of testicular enhancement patterns at dynamic contrast-enhanced subtraction MR imaging

PURPOSE: To evaluate testicular enhancement patterns in various scrotal disorders at dynamic contrast medium-enhanced subtraction magnetic resonance (MR) imaging. MATERIALS AND METHODS: Forty-two patients with scrotal symptoms (22 testicular diseases, 20 extratesticular scrotal disorders) underwent three-dimensional (3D) fast field-echo or fast spin-echo dynamic subtraction MR imaging after injection of paramagnetic contrast medium. The relative percentages of peak height and mean slope of the testes on the affected side were compared with those on the unaffected side by using time-signal intensity curves. RESULTS: Extratesticular scrotal disorders (time-signal intensity curve mean peak height, 93.1%; mean slope, 89.8%) showed gradual and progressive increase in homogeneous testicular contrast enhancement in all normal testes. Relative percentages of peak height and mean slope of testicular torsion (mean peak height, 17.3%; mean slope, 10.6%), infarction (mean peak height, 30.4%; mean slope, 19.8%), traumatic hemorrhagic necrosis (mean peak height, -3.5%; mean slope, -12.0%), and epidermoid cyst (mean peak height, -6.6%; mean slope, -14.2%) were significantly lower than those of extratesticular scrotal disorders. Acute mumps orchitis (mean peak height, 135.1%; mean slope, 307.5%) and malignant testicular tumor (mean peak height, 178.7%; mean slope, 467.6%) showed higher relative percentages of peak height and mean slope. CONCLUSION: Dynamic contrast-enhanced subtraction MR imaging can provide information about testicular perfusion on the basis of contrast enhancement and can be used to differentiate testicular diseases from scrotal disorders.