HASTE序列磁共振胰胆管成像:单层和多层法成像技术比较研究

目的　采用HASTE磁共振成像技术进行磁共振胰胆管成像并比较 2种不同成像方法优劣。方法　对 66例临床怀疑胰胆管病变患者进行磁共振检查 ,所有病例全部行胰胆系常规SE及梯度序列矢冠轴位相扫描和HASTE序列 2种不同方法 (多层薄块采集MIP重建法和连续单层厚块采集法 )MRCP成像。对 2种不同HASTE序列显示胰胆管病变的优缺点进行比较。结果　 66例中共有 44例确诊为胰胆系病变 ,阳性率 67% ( 4 4/ 66)。采用单层法 66例 ( 10 0 % )全部达到诊断标准 ;多层法有 5 8例 ( 88% )达到诊断标准。单层法采集空间分辨率较高 ,且采集时间短 ,但受血管伪影影响较明显。多层法采集密度分辨率高 ,但运动伪影明显。结论　单层采集HASTE屏气MRCP成像结合常规SE及梯度序列矢冠轴位相扫描是胰胆管病变磁共振检查的最佳方法之一     

单层TSE序列及多层HASTE序列磁共振胰胆管成像技术在临床应用价值的比较

目的:比较磁共振胰胆管成像技术的2种成像方法,探讨有助于临床诊断胆系病变的磁共振检查的最佳方法。方法:分析经手术病理或活检证实的35例胰胆管病变患者2种不同方法(单层TSE序列及多层HASTE序列)MRCP影像表现,比较二者显示胰胆管病变的优缺点。结果:单层TSE序列采集时间短,空间分辨率高,受运动伪影影响小;多层HASTE序列采集时间较长,运动伪影明显。结论:单层TSE-MRCP成像结合常规SE及梯度序列冠轴位相扫描是胰胆管病变的磁共振检查的最佳方法之一。     

单次激发磁共振胰胆管成像与常规磁共振胰胆管造影的比较

比较单次激发磁共振胰胆管成像(SSMRCP)和常规磁共振胰胆管造影(CMRCP),评价SSMRCP的临床应用 价值。材料与方法81例梗阻性黄疸、1例胆管-空肠吻合术后及61例无黄疸患者行OMRC、SSMRC单层及多层扫描, 比较两种技术诊断的准确性。结果三个序列均能显示胆管病变部位、疾病特征、近侧扩张胆管以及远侧正常胰胆管;显 示扩张胆管直径三个序列间没有显著性差异;SSMRCP多层显示胆管病变细节较好,而SSMRCP单层显示胰管则明显优 于另两种方法。结论SSSMRCP可代替OMRCP,准确地、更快速地诊断胆管系统疾病,并能更好地显示正常胰管。     

磁共振胰胆管成像序列的比较研究

目的: 比较磁共振胰胆管成像(MRCP)不同序列对胰胆管树的显示能力及其临床应用.材料和方法: 对24例正常成年志愿者及30例胰胆管梗阻性疾病患者行FSE、FSE-XL和SSFSE MRCP检查,并对各扫描序列的胰胆管显示情况进行分析.结果: FSE-XL和SSFSE扫描序列对胰胆管及病变部位的显示明显优于常规FSE扫描序列,SSFSE又优于FSE-XL扫描序列.SSFSE扫描序列能充分显示正常胰胆管树,对胰胆管梗阻性疾病的检出率也较高.结论: SSFSE扫描序列与能多方位观察胰胆管情况的FSE-XL扫描序列联合应用,可明显提高对胰胆管梗阻性疾病的检出率.     

磁共振胰胆管成像序列的比较研究

目的：比较磁共振胰胆管成像（MRCP）不同序列对胰胆管树的显示能力及其临床应用。材料和方法：对24例正常成年志愿者及30例胰胆管梗阻性疾病患者行FSE、FSE—XL和SSFSEMRCP检查，并对各扫描序列的胰胆管显示情况进行分析。结果：FSE—XL和SSFSE扫描序列对胰胆管及病变部位的显示明显优于常规FSE扫描序列，SSFSE又优于FSE—XL扫描序列。SSFSE扫描序列能充分显示正常胰胆管树，对胰胆管梗阻性疾病的检出率也较高。结论：SSFSE扫描序列与能多方位观察胰胆管情况的FSE—XL扫描序列联合应用，可明显提高对胰胆管梗阻性疾病的检出率。     

HASTE磁共振胰胆管成像诊断胆道恶性梗阻病变的价值

目的探讨HASTE磁共振胰胆管造影在胆道恶性梗阻病变诊断中的应用价值。方法分析经手术病理或活检证实的43例胆道恶性梗阻病变患者的HASTE-MRCP影像表现。结果HASTE-MRCP诊断胆道恶性梗阻,其定位诊断符合率为100%,定性诊断符合率为75%。结论HASTE-MRCP在胆道恶性梗阻性病变的诊断中具有良好的应用价值。     

恶性胆道梗阻的磁共振胰胆管成像表现与病理对照研究

目的研究恶性胆道梗阻的MR胰胆管成像表现、分型,并与病理对照。方法37例恶性胆道梗阻患者,常规T1WI、T2WI及脂肪抑制T2WI检查后,行MRCP检查。根据病变发生部位分型。并将每种类型的MRCP表现与病理组织学结果对照。结果37例患者,根据MRCP表现分成4种类型。其中I型3例,病理为肝内胆管细胞癌;II型7例,病理为胆管癌4例,胆囊癌3例;Ⅲ型14例,胆管癌4例,胆囊癌3例,胰头癌2例,壶腹癌3例,十二指肠癌2例;Ⅳ型13例,胆管癌6例,胰头癌4例,壶腹癌3例。结论恶性胆道梗阻有不同的MRCP表现,反映其病理组织学变化。     

磁共振胰胆管成像对恶性胆道梗阻的诊断价值

目的：评价磁共振胰胆管成像（MRCP）对恶性胆道梗阻性疾病的临床诊断价值，探讨肝外恶性胆道梗阻的MRCP、MRI诊断及鉴别诊断。方法：回顾性分析69例恶性胆道梗阻患者的MRI及MRCP表现，并与CT、US、直接胆道造影和手术病理结果对照。MRCP采用二维（2D）和／或三维（3D）屏气半傅立叶转换快速自旋回波（FASE）序列T2加权成像技术。结果：69例MRCP检查均一次成功，全部病例胰胆管显示满意，与直接胆道造影对照，二者所获图像极其相似。MRCP对恶性胆道梗阻定位诊断准确率为98．5％定性诊断准确率为95．6％。结论：MRCP对恶性胆道梗阻定位及定性诊断优于CT和US，是诊断恶性胆道梗阻的一种有效的非侵袭性的检查方法。     

磁共振胰胆管成像技术的临床应用研究

目的：探讨磁共振胰胆管成像（MRCP）对胰、胆管疾病的诊断价值。方法：采用快速自旋回波（FSE）重T2加权技术对221例患进行了MRCP检查。结果：221例患中，MRCP正确诊断良性病变134例和恶性病变75例，定性诊断和定位诊断准确率分别为94．6％（209／221）和100％（221／221）。对良、恶性病变定性诊断准确率分别为96．4％（134／139）和91．4％（75／82）。结论:MRCP对胰、胆管疾病具有极高的诊断准确率，是一种颇有应用前景的影像技术。     

Diffusion-weighted imaging (DWI) in MR mammography (MRM): clinical comparison of echo planar imaging (EPI) and half-Fourier single-shot turbo spin echo (HASTE) diffusion techniques

Diffusion-weighted imaging (DWI) techniques have shown potential to differentiate between benign and malignant neoplasms. However, the diagnostic significance of using DWI under routine conditions remains unclear. This study investigated the use of echo planar imaging (EPI) and half-Fourier acquired single-shot turbo spin echo (HASTE)-DWI with respect to the three parameters: lesion visibility, apparent diffusion coefficient (ADC) measurements, and size estimation. Following MRM (1.5 T), EPI- and HASTE-DWI were applied in 65 patients. Lesion visibility on DWI was compared with lesion visibility on subtracted contrast-enhanced T1w images (CE-T1w). Statistical tests were applied to diameter, visibility, and ADC value measurements. Seventy-four lesions were identified. ADC value measurements did not differ significantly between the two DWI sequences. The sensitivity and specificity of routine diagnostics (97.4% and 85.7%) were superior to EPI-DWI (87.2% and 82.9%) and HASTE-DWI (76.9% and 88.6%). Selecting only nonmass lesions, DWI did not prove to be of diagnostic value. Lesion demarcation by DWI was significantly lower compared with that by CE-T1w, with EPI-DWI showing the better performance (p < 0.001). No significant differences were found for size measurements between CE-T1w and DWI. Although clearly inferior compared with CE-T1w imaging, both DWI techniques are applicable for lesion assessment and size measurements.     

Evaluation of Aqueductal Patency in Patients with Hydrocephalus: Three-Dimensional High-Sampling-Efficiency Technique (SPACE) versus Two-Dimensional Turbo Spin Echo at 3 Tesla

Objective

To compare the accuracy of diagnosing aqueductal patency and image quality between high spatial resolution three-dimensional (3D) high-sampling-efficiency technique (sampling perfection with application optimized contrast using different flip angle evolutions [SPACE]) and T2-weighted (T2W) two-dimensional (2D) turbo spin echo (TSE) at 3-T in patients with hydrocephalus.

Materials and Methods

This retrospective study included 99 patients diagnosed with hydrocephalus. T2W 3D-SPACE was added to the routine sequences which consisted of T2W 2D-TSE, 3D-constructive interference steady state (CISS), and cine phase-contrast MRI (PC-MRI). Two radiologists evaluated independently the patency of cerebral aqueduct and image quality on the T2W 2D-TSE and T2W 3D-SPACE. PC-MRI and 3D-CISS were used as the reference for aqueductal patency and image quality, respectively. Inter-observer agreement was calculated using kappa statistics.

Results

The evaluation of the aqueductal patency by T2W 3D-SPACE and T2W 2D-TSE were in agreement with PC-MRI in 100% (99/99; sensitivity, 100% [83/83]; specificity, 100% [16/16]) and 83.8% (83/99; sensitivity, 100% [67/83]; specificity, 100% [16/16]), respectively (p < 0.001). No significant difference in image quality between T2W 2D-TSE and T2W 3D-SPACE (p = 0.056) occurred. The kappa values for inter-observer agreement were 0.714 for T2W 2D-TSE and 0.899 for T2W 3D-SPACE.

Conclusion

Three-dimensional-SPACE is superior to 2D-TSE for the evaluation of aqueductal patency in hydrocephalus. T2W 3D-SPACE may hold promise as a highly accurate alternative treatment to PC-MRI for the physiological and morphological evaluation of aqueductal patency.     

Half‐fourier‐acquisition single‐shot turbo spin‐echo (HASTE) MRI of the lung at 3 Tesla using parallel imaging with 32‐receiver channel technology

Purpose

To assess the feasibility of half‐Fourier‐acquisition single‐shot turbo spin‐echo (HASTE) of the lung at 3 Tesla (T) using parallel imaging with a prototype of a 32‐channel torso array coil, and to determine the optimum acceleration factor for the delineation of intrapulmonary anatomy.

Materials and Methods

Nine volunteers were examined on a 32‐channel 3T MRI system using a prototype 32‐channel‐torso‐array‐coil. HASTE‐MRI of the lung was acquired at both, end‐inspiratory and end‐expiratory breathhold with parallel imaging (Generalized autocalibrating partially parallel acquisitions = GRAPPA) using acceleration factors ranging between R = 1 (TE = 42 ms) and R = 6 (TE = 16 ms). The image quality of intrapulmonary anatomy and subjectively perceived noise level was analyzed by two radiologists in consensus. In addition quantitative measurements of the signal‐to‐noise ratio (SNR) of HASTE with different acceleration factors were assessed in phantom measurements.

Results

Using an acceleration factor of R = 4 image blurring was substantially reduced compared with lower acceleration factors resulting in sharp delineation of intrapulmonary structures in expiratory scans. For inspiratory scans an acceleration factor of 2 provided the best image quality. Expiratory scans had a higher subjectively perceived SNR than inspiratory scans.

Conclusion

Using optimized multi‐element coil geometry HASTE‐MRI of the lung is feasible at 3T with acceleration factors up to 4. Compared with nonaccelerated acquisitions, shorter echo times and reduced image blurring are achieved. Expiratory scanning may be favorable to compensate for susceptibility associated signal loss at 3T. J. Magn. Reson. Imaging 2009;30:541–546. © 2009 Wiley‐Liss, Inc.     

Ultra‐short echo time (UTE) MR imaging of the lung: Comparison between normal and emphysematous lungs in mutant mice

Purpose:

To investigate the utility of ultra‐short echo time (UTE) sequence as pulmonary MRI to detect non‐uniform disruption of lung architecture that is typical of emphysema.

Materials and Methods:

MRI of the lungs was conducted with a three‐dimensional UTE sequence in transgenic mice with severe emphysema and their wild‐type littermates in a 3 Tesla clinical MR system. Measurements of the signal intensity (SI) and transverse relaxation time (T2*) of the lung parenchyma were performed with various echo times (TEs) ranging from 100 μs to 2 ms.

Results:

Much higher SI of the lung parenchyma was observed at an UTE of 100 μs compared with longer TEs. The emphysematous lungs had reduced SIs and T2* than the controls, in particular at end‐expiratory phase. The results suggested that both SI and T2* in lung parenchyma measured with the method represent fractional volume of lung tissue.

Conclusion:

The UTE imaging provided MR signal from the lung parenchyma. Moreover, the UTE sequence was sensitive to emphysematous changes and may provide a direct assessment of lung parenchyma. UTE imaging has the potential to assist detection of localized pathological destruction of lung tissue architecture in emphysema. J. Magn. Reson. Imaging 2010;32:326–333. © 2010 Wiley‐Liss, Inc.     

Comparison of two ultrashort echo time sequences for the quantification of T(1) within phantom and human Achilles tendon at 3 T

Ultrashort echo time (UTE) techniques enable direct imaging of musculoskeletal tissues with short T₂ allowing measurement of T₁ relaxation times. This article presents comparison of optimized 3D variable flip angle UTE (VFA‐UTE) and 2D saturation recovery UTE (SR‐UTE) sequences to quantify T₁ in agar phantoms and human Achilles tendon. Achilles tendon T₁ values for asymptomatic volunteers were compared to Achilles tendon T₁ values calculated from patients with clinical diagnoses of spondyloarthritis (SpA) and Achilles tendinopathy using an optimized VFA‐UTE sequence. T₁ values from phantom data for VFA‐ and SR‐UTE compare well against calculated T₁ values from an assumed gold standard inversion recovery spin echo sequence. Mean T₁ values in asymptomatic Achilles tendon were found to be 725 ± 42 ms and 698 ± 54 ms for SR‐ and VFA‐UTE, respectively. The patient group mean T₁ value for Achilles tendon was found to be 957 ± 173 ms (P < 0.05) using an optimized VFA‐UTE sequence with pulse repetition time of 6 ms and flip angles 4, 19, and 24°, taking a total 9 min acquisition time. The VFA‐UTE technique appears clinically feasible for quantifying T₁ in Achilles tendon. T₁ measurements offer potential for detecting changes in Achilles tendon due to SpA without need for intravenous contrast agents. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.     

食管内照射支架与普通支架临床应用的初步效果对比

目的:对比食管内照射支架与普通支架的临床应用效果。方法:选择18例经食管钡餐、电子胃镜及活检证实的中晚期食管癌患者,分为两组各9例,分别放置普通国产支架及125I种子源内照射支架,利用TPS计算出所放种子源。结果:经随访,普通支架组生存期限为3个月~2.5年,内照射支架组生存期限为6个月~1.5年。两组并发症基本相同,内照射组血常规及免疫指标改变与普通支架组无明显差异。普通支架可引起后期狭窄,而内照射支架无再次狭窄。内照射支架组半年生存期限明显延长。结论:125I种子源内照射支架治疗中晚期食管癌的疗效优于普通支架,种子源置入是安全、有效的。     

Pancreatic diffusion‐weighted imaging (DWI): Comparison between mass‐forming focal pancreatitis (FP), pancreatic cancer (PC), and normal pancreas

Purpose

To compare diffusion‐weighted imaging (DWI) findings and the apparent diffusion coefficient (ADC) values of pancreatic cancer (PC), mass‐forming focal pancreatitis (FP), and the normal pancreas.

Materials and Methods

DWI (b = 0 and 600 seconds/mm²) findings of 14 patients with mass‐forming FP proven by histopathology and or clinical follow‐up, 10 patients with histopathologically‐proven PC, and 14 subjects with normal pancreatic exocrine function and normal imaging findings were retrospectively evaluated. ADC values of the masses, the remaining pancreas, and the normal pancreas were measured.

Results

On b = 600 seconds/mm² DWI, mass‐forming FP was visually indistinguishable from the remaining pancreas whereas PC was hyperintense relative to the remaining pancreas. The mean ADC value of PC (1.46 ± 0.18 mm²/second) was significantly lower than the remaining pancreas (2.11 ± 0.32 × 10^–3 mm²/second; P < 0.0001), mass‐forming FP (2.09 ± 0.18 × 10^–3 mm²/second; P < 0.0001), and pancreatic gland in the control group (1.78 ± 0.07 × 10^–3 mm²/second; P < 0.0005). There was no significant difference of ADC values between the mass‐forming focal pancreatitis and the remaining pancreas (2.03 ± 0.2 × 10^–3 mm²/second; P > 0.05).

Conclusion

Differences on DWI may help to differentiate PC, mass‐forming FP, and normal pancreas from each other. J. Magn. Reson. Imaging 2009;29:350–356. © 2009 Wiley‐Liss, Inc.