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1.
Ueli Studler MD Lawrence M. White MD Gustav Andreisek MD Sheena Luu BSc Hai‐Ling Margaret Cheng PhD Marshall S. Sussman PhD 《Journal of magnetic resonance imaging : JMRI》2010,32(2):394-398
Purpose:
To evaluate the impact of motion on T1 values acquired by using either inversion‐recovery fast spin echo (IR‐FSE) or three‐dimensional (3D) spoiled gradient recalled‐echo (SPGR) sequences for delayed gadolinium‐enhanced magnetic resonance imaging of cartilage (dGEMRIC) in volunteers.Materials and Methods:
Single‐slice IR‐FSE and 3D SPGR sequences were applied to perform dGEMRIC in five healthy volunteers. A mutual information‐based approach was used to correct for image misregistration. Displacements were expressed as averaged Euclidean distances and angles. Averages of differences in goodness of fit (Δχ2) tests and averages of relative differences in T1 values (ΔT1) before and after motion correction were computed.Results:
Maximum Euclidean distance was 3.5 mm and 1.2 mm for IR‐FSE and SPGR respectively. Mean ± SD of Δχ2 were 10.18 ± 8.4 for IR‐FSE and ?1.37 ± 5.5 for SPGR. Mean ± SD of ΔT1 were 0.008 ± 0.0048 for IR‐FSE and ?0.002 ± 0.019 for FSPGR. Pairwise comparison of Δχ2 values showed a significant difference for IR‐FSE, but not for 3D‐SPGR. Significantly greater variability in T1 values was also noted for IR‐FSE than for 3D‐SPGR.Conclusion:
Involuntary motion has a significant influence on T1 values acquired with IR‐FSE, but not with 3D‐SPGR in healthy volunteers. J. Magn. Reson. Imaging 2010;32:394–398. © 2010 Wiley‐Liss, Inc.2.
Philipp Heusch MD Hans‐Jörg Wittsack PhD Patric Kröpil MD Dirk Blondin MD Michael Quentin MD Janina Klasen MD Gael Pentang MSc Gerald Antoch MD Rotem S. Lanzman MD 《Journal of magnetic resonance imaging : JMRI》2013,37(1):233-236
Purpose:
To evaluate the impact of renal blood flow on apparent diffusion coefficients (ADC) and fractional anisotropy (FA) using time‐resolved electrocardiogram (ECG)‐triggered diffusion‐tensor imaging (DTI) of the human kidneys.Materials and Methods:
DTI was performed in eight healthy volunteers (mean age 29.1 ± 3.2) using a single slice coronal echoplanar imaging (EPI) sequence (3 b‐values: 0, 50, and 300 s/mm2) at the timepoint of minimum (20 msec after R wave) and maximum renal blood flow (200 msec after R wave) at 3T. Following 2D motion correction, region of interest (ROI)‐based analysis of cortical and medullary ADC‐ and FA‐values was performed.Results:
ADC‐values of the renal cortex at maximum blood flow (2.6 ± 0.19 × 10?3 mm2/s) were significantly higher than at minimum blood flow (2.2 ± 0.11 × 10?3 mm2/s) (P < 0.001), while medullary ADC‐values did not differ significantly (maximum blood flow: 2.2 ± 0.18 × 10?3 mm2/s; minimum blood flow: 2.15 ± 0.14 × 10?3 mm2/s). FA‐values of the renal medulla were significantly greater at maximal blood (0.53 ± 0.05) than at minimal blood flow (0.47 ± 0.05) (P < 0.01). In contrast, cortical FA‐values were comparable at different timepoints of the cardiac cycle.Conclusion:
ADC‐values in the renal cortex as well as FA‐values in the renal medulla are influenced by renal blood flow. This impact has to be considered when interpreting renal ADC‐ and FA‐values. J. Magn. Reson. Imaging 2013;37:233–236. © 2012 Wiley Periodicals, Inc.3.
Jiang Du Atsushi M. Takahashi Christine B. Chung 《Journal of magnetic resonance imaging : JMRI》2009,29(2):412-421
Purpose
To investigate ultrashort TE spectroscopic imaging (UTESI) of short T2 tissues in the musculoskeletal (MSK) system.Materials and Methods
Ultrashort TE pulse sequence is able to detect rapidly decaying signals from tissues with a short T2 relaxation time. Here a time efficient spectroscopic imaging technique based on a multiecho interleaved variable TE UTE acquisition is proposed for high‐resolution spectroscopic imaging of the short T2 tissues in the MSK system. The projections were interleaved into multiple groups with the data for each group being collected with progressively increasing TEs. The small number of projections in each group sparsely but uniformly sampled k‐space. Spectroscopic images were generated through Fourier transformation of the time domain images at variable TEs. T2* was quantified through exponential fitting of the time domain images or line shape fitting of the magnitude spectrum. The feasibility of this technique was demonstrated in volunteer and cadaveric specimen studies on a clinical 3T scanner.Results
UTESI was applied to six cadaveric specimens and four human volunteers. High spatial resolution and contrast images were generated for the deep radial and calcified layers of articular cartilage, menisci, ligaments, tendons, and entheses, respectively. Line shape fitting of the UTESI magnitude spectroscopic images show a short T2* of 1.34 ± 0.56 msec, 4.19 ± 0.68 msec, 3.26 ± 0.34 msec, 1.96 ± 0.47 msec, and 4.21 ± 0.38 msec, respectively.Conclusion
UTESI is a time‐efficient method to image and characterize the short T2 tissues in the MSK system with high spatial resolution and high contrast. J. Magn. Reson. Imaging 2009;29:412–421. © 2009 Wiley‐Liss, Inc.4.
Jingsi Xie BS Peng Lai PhD Himanshu Bhat MS Debiao Li PhD 《Journal of magnetic resonance imaging : JMRI》2010,31(5):1230-1235
Purpose
To evaluate the feasibility of improving 3.0T steady‐state free precession (SSFP) whole‐heart coronary magnetic resonance angiography (MRA) using short‐TR (repetition time) VIPR (vastly undersampled isotropic projection reconstruction).Materials and Methods
SSFP is highly sensitive to field inhomogeneity. VIPR imaging uses nonselective radiofrequency pulses, allowing short TR and reduced banding artifacts, while achieving isotropic 3D resolution. Coronary artery imaging was performed in nine healthy volunteers using SSFP VIPR. TR was reduced to 3.0 msec with an isotropic spatial resolution of 1.3 × 1.3 × 1.3 mm3. Image quality, vessel sharpness, and lengths of major coronary arteries were measured. Comparison between SSFP using Cartesian trajectory and SSFP using VIPR trajectory was performed in all volunteers.Results
Short‐TR SSFP VIPR resulted in whole‐heart images without any banding artifacts, leading to excellent coronary artery visualization. The average image quality score for VIPR‐SSFP was 3.12 ± 0.42 out of four while that for Cartesian SSFP was 0.92 ± 0.61. A significant improvement (P < 0.05) in image quality was shown by Wilcoxon comparison. The visualized coronary artery lengths for VIPR‐SSFP were: 10.13 ± 0.79 cm for the left anterior descending artery (LAD), 7.90 ± 0.91 cm for the left circumflex artery (LCX), 7.50 ± 1.65 cm for the right coronary artery (RCA), and 1.84 ± 0.23 cm for the left main artery (LM). The lengths statistics for Cartesian SSFP were 1.57 ± 2.02 cm, 1.54 ± 1.93 cm, 0.94 ± 1.17 cm, 0.46 ± 0.53 cm, respectively. The image sharpness was also increased from 0.61 ± 0.13 (mm?1) in Cartesian‐SSFP to 0.81 ± 0.11 (mm?1) in VIPR‐SSFP.Conclusion
With VIPR trajectory the TR is substantially decreased, reducing the sensitivity of SSFP to field inhomogeneity and resulting in whole‐heart images without banding artifacts at 3.0T. Image quality improved significantly over Cartesian sampling. J. Magn. Reson. Imaging 2010; 31:1230–1235. © 2010 Wiley‐Liss, Inc.5.
Yamamoto S Watanabe A Nakamura J Ohtori S Harada Y Kishida S Wada Y Takahashi K 《Journal of magnetic resonance imaging : JMRI》2011,34(5):1151-1158
Purpose:
To evaluate articular cartilage degeneration with transverse relaxation time (T2) mapping in systemic lupus erythematosus (SLE) patients with noncollapsed and asymptomatic osteonecrosis of the femoral head associated with corticosteroids.Materials and Methods:
T2 mapping with a 1.5‐T magnetic resonance imaging system was prospectively performed for 28 normal hips from 14 healthy volunteers (control group) and 15 hips from 10 SLE patients that met the inclusion criteria of noncollapsed and asymptomatic osteonecrosis of the femoral head (osteonecrosis group). Exclusion criteria were past experience of pain, trauma, infection, or prior hip joint surgery. Distribution of T2 values of the femoral head cartilage were compared between the control group and the osteonecrosis group with respect to acetabular dysplasia by center‐edge angle (CEA).Results:
T2 values of the femoral head cartilage were significantly higher in the osteonecrosis group than in the control group (34.4 msec vs. 30.8 msec, P = 0.001). Multiple regression analysis revealed that the osteonecrosis group and decreased CEA was significantly associated with high T2 values (T2 value = 34.6 + 3.6 × [osteonecrosis] ? 0.14 × CEA, R2 = 0.52, P = 0.003).Conclusion:
Degeneration of articular cartilage was associated with osteonecrosis of the femoral head in SLE patients and acetabular dysplasia. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.6.
Carl Siversson MS Carl‐Johan Tiderius MD PhD Leif Dahlberg MD PhD Jonas Svensson PhD 《Journal of magnetic resonance imaging : JMRI》2009,30(4):834-841
Purpose
To present an evaluation method for three‐dimensional Look‐Locker (3D‐LL) based T1 quantification, calculating correct T1 values independent of local flip angle (FA) variations. The method was evaluated both in phantoms and in vivo in a delayed Gadolinium Enhanced MRI of Cartilage (dGEMRIC) study with 33 subjects.Materials and Methods
T1 was measured with 3D‐LL, using both local FA correction and a precalculated FA slice profile, and compared with standard constant FA correction, for all slices in phantoms and in both femur condyles in vivo. T1 measured using two‐dimensional Inversion Recovery (2D‐IR) was used as gold standard.Results
Due to the FA being slice dependent, the standard constant FA correction results in erroneous T1 (systematic error = 109.1 ms in vivo), especially in the outer slices. With local FA correction, the calculated T1 is excellent for all slices in phantoms (<5% deviation from 2D‐IR). In vivo the performance is lower (systematic error = ?57.5 ms), probably due to imperfect inversion. With precalculated FA correction the performance is very good also in vivo (systematic error = 13.3 ms).Conclusion
With the precalculated FA correction method, the 3D‐LL sequence is robust enough for in vivo dGEMRIC, even outside the centermost slices. J. Magn. Reson. Imaging 2009;30:834–841. © 2009 Wiley‐Liss, Inc.7.
Chang G Wiggins GC Xia D Lattanzi R Madelin G Raya JG Finnerty M Fujita H Recht MP Regatte RR 《Journal of magnetic resonance imaging : JMRI》2012,35(2):441-448
Purpose:
To compare a new birdcage‐transmit, 28‐channel receive array (28‐Ch) coil and a quadrature volume coil for 7T morphologic MRI and T2 mapping of knee cartilage.Materials and Methods:
The right knees of 10 healthy subjects were imaged on a 7T whole body magnetic resonance (MR) scanner using both coils. 3D fast low‐angle shot (3D‐FLASH) and multiecho spin‐echo (MESE) sequences were implemented. Cartilage signal‐to‐noise ratio (SNR), contrast‐to‐noise ratio (CNR), thickness, and T2 values were assessed.Results:
SNR/CNR was 17%–400% greater for the 28‐Ch compared to the quadrature coil (P ≤ 0.005). Bland–Altman plots show mean differences between measurements of tibial/femoral cartilage thickness and T2 values obtained with each coil to be small (?0.002 ± 0.009 cm / 0.003 ± 0.011 cm) and large (?6.8 ± 6.7 msec/?8.2 ± 9.7 msec), respectively. For the 28‐Ch coil, when parallel imaging with acceleration factors (AF) 2, 3, and 4 was performed SNR retained was: 62%–69%, 51%–55%, and 39%–45%.Conclusion:
A 28‐Ch knee coil provides increased SNR/CNR for 7T cartilage morphologic imaging and T2 mapping. Coils should be switched with caution during clinical studies because T2 values may differ. The greater SNR of the 28‐Ch coil could be used to perform parallel imaging with AF2 and obtain similar SNR as the quadrature coil. J. Magn. Reson. Imaging 2012;441‐448. © 2011 Wiley Periodicals, Inc.8.
P.C. Sundgren MD PhD V. Nagesh PhD A. Elias MD C. Tsien MD L. Junck MD D.M. Gomez Hassan MD PhD T.S. Lawrence MD T.L. Chenevert PhD L. Rogers MD P. McKeever MD PhD Y. Cao PhD 《Journal of magnetic resonance imaging : JMRI》2009,29(2):291-297
Purpose
To assess if interval changes in metabolic status in normal cerebral tissue after radiation therapy (RT) can be detected by 2D CSI (chemical shift imaging) proton spectroscopy.Materials and Methods
Eleven patients with primary brain tumors undergoing cranial radiation therapy (RT) were included. 2D‐CSI MRS was performed before, during, and after the course of RT with the following parameters: TE/TR 144/1500 ms, field of view (FOV) 24, thickness 10 mm, matrix 16 × 16. The metabolic ratios choline/creatine (Cho/Cr), N‐acetylaspartate (NAA)/Cr, and NAA/Cho in normal brain tissue were calculated.Results
NAA/Cr and Cho/Cr were significantly decreased at week 3 during RT and at 1 month and 6 months after RT compared to values prior to RT (P < 0.01). The NAA/Cr ratio decreased by ?0.19 ± 0.05 (mean ± standard error [SE]) at week 3 of RT, ?0.14 ± 0.06 at the last week of RT, ?0.14 ± 0.05 at 1 month after RT, and ?0.30 ± 0.08 at 6 months after RT compared to the pre‐RT value of 1.43 ± 0.04. The Cho/Cr ratio decreased by ?0.27 ± 0.05 at week 3 of RT, ?0.11 ± 0.05 at the last week of RT, ?0.26 ± 0.05 at 1 month after RT and ?0.25 ± 0.07 at 6 months after RT from the pre‐RT value of 1.29 ± 0.03. Changes in Cho/Cr were correlated with the interaction of the radiation dose and dose‐volume at week 3 of RT, during the last week of RT (P < 0.005), and at 1 month after RT (P = 0.017).Conclusion
The results of this study suggest that MRS can detect early metabolic changes in normal irradiated brain tissue. J. Magn. Reson. Imaging 2009;29:291–297. © 2009 Wiley‐Liss, Inc.9.
Sachiko Yuen MD PhD Kei Yamada MD PhD Mariko Goto MD PhD Kaori Nishida MD Akiko Takahata MD PhD Tsunehiko Nishimura MD PhD 《Journal of magnetic resonance imaging : JMRI》2009,29(5):1080-1084
Purpose
To investigate the effect of gadolinium (Gd)‐DTPA on the apparent diffusion coefficient (ADC) of breast carcinoma and to analyze the relationship between pre/postcontrast ADC and the degree of contrast enhancement.Materials and Methods
Nineteen histopathologically confirmed breast carcinomas (mean size = 22 mm) were analyzed. Their ADCs before and after contrast administration were measured. The contrast‐to‐noise ratios (CNRs) of the tumors were measured on fat‐suppressed 3D T1‐weighted images in precontrast, early, and late postcontrast phases. These results were correlated with the measured ADC values.Results
A significant decrease in the measured ADC was noted after contrast administration (?23%, P = 0.01). Lesions with relatively high ADC before contrast (>1.3 × 10?3 mm2/sec; n = 12) demonstrated a larger degree of ADC reduction (mean 34%) than lesions with low ADC (≤1.3 × 10?3 mm2/sec; n = 7) (mean 4.5%). When an early postcontrast image was used as a surrogate marker of malignant potential, we found a significant inverse correlation with postcontrast ADC (γ = ?0.57, P = 0.02).Conclusion
Postcontrast ADC exhibited lower values than precontrast ADC, which is thought to reflect suppression of the microperfusion‐induced effect on diffusion‐weighted imaging. Postcontrast ADC may be a better indicator than precontrast ADC to reflect malignant potential of tumors. J. Magn. Reson. Imaging 2009;29:1080–1084. © 2009 Wiley‐Liss, Inc.10.
Jing Ren MD Yi Huan MD PhD Fang Li MD He Wang MD PhD YaLi Ge MB YingJuan Chang MM Hong Yin MD PhD LiJun Sun MD PhD 《Journal of magnetic resonance imaging : JMRI》2009,30(2):351-356
Purpose
To retrospectively determine the diffusion‐weighted imaging (DWI) characteristics and apparent diffusion coefficient (ADC) values of prostate carcinoma (PCa) with urinary bladder invasion, and to compare the accuracy of T2‐weighted MRI alone and T2 combined with DWI for predicting urinary bladder invasion.Materials and Methods
Sixty‐eight patients with proven PCa were diagnosed with urinary bladder invasion after conventional magnetic resonance imaging (MRI) and DWI (b value = 750 sec/mm2) examinations. All the 68 cases underwent cystoscopy examination. DWI appearances of all urinary bladder invasion and a normal urinary bladder wall were analyzed, and their ADC values were measured. T2 images alone and then T2 images combined with DWI were scored for the likelihood of urinary bladder invasion on the basis of radiologists' written reports. The area under the receiver operating characteristic curve (AUC) was used to assess accuracy. Statistical significance was inferred at P < 0.05.Results
After cystoscopy examination, 45 (66%) of 68 cases were pathologically proven urinary bladder invasion. The mean ADCs for urinary bladder invasion and normal urinary bladder wall were (0.963 ± 0.155) × 10?3mm2/sec and (1.517 ± 0.103) × 10?3mm2/sec, respectively. The ADC values of urinary bladder invasion were significantly lower than those of normal urinary bladder wall (P = 0.000). The AUC for T2‐weighted imaging plus DW imaging (0.861) was significantly larger than that for T2‐weighted imaging alone (0.734) or for DW imaging alone (0.703) (P < 0.001).Conclusion
Urinary bladder invasion had lower ADC values compared with normal urinary bladder wall. T2 images plus DWI is significantly better than T2‐weighted imaging alone in the detection of urinary bladder invasion in patients with PCa. J. Magn. Reson. Imaging 2009. © 2009 Wiley‐Liss, Inc.11.
Gulnur Erdem MD Tamer Erdem MD Hakki Muammer Karakas MD Deniz Yakar Mutlu MD Ahmet Kemal Fırat MD Ibrahim Sahin MD Alpay Alkan MD 《Journal of magnetic resonance imaging : JMRI》2010,31(1):94-100
Purpose:
To reveal the possible role of diffusion‐weighted images (DWI) in the differential diagnosis of benign and malignant thyroid nodules by comparing the results of fine‐needle aspiration cytology (FNAC).Materials and Methods:
In an 18‐month period (December 2005 to May 2007), 27 cases with benign thyroid nodules with a total of 52 benign nodules, nine cases with thyroid gland malignancy, and 24 healthy control cases were included in the study. Cases that were indicated to undergo to FNAC examination and sent by a clinician for biopsy to the radiology unit were included in the study to assess the cytopathologic confirmation of the clinic, ultrasonographic, and magnetic resonance imaging (MRI) findings.Results:
The mean apparent diffusion coefficient (ADC) values of thyroid nodules were 2745.3 ± 601.1 × 10?6 mm2/s (1605–3899 × 10?6mm2/s) in the benign group and 695.2 ± 312.5 × 10?6mm2/s (165–1330 × 10?6mm2/s) in the malignant group. Normal thyroid tissues had mean ADC values of 1344.1 ± 276.4 × 10?6 mm2/s (1015–1764 × 10?6mm2/s). The ADC values of three subgroups were significantly different (P = 0.0001). A reduced ADC was observed in most types of malignant tumors due to the consequent decrease of the extracellular extravascular space.Conclusion:
Our preliminary results showed that ADC values of nodules may provide useful data about the nature of a thyroid nodule. J. Magn. Reson. Imaging 2010;31:94–100. © 2009 Wiley‐Liss, Inc.12.
Amir Eissa MSc R. Marc Lebel MSc Jeff R. Korzan MD Anna E. Zavodni MD Kenneth G. Warren MD Ingrid Catz MSc Derek J. Emery MD Alan H. Wilman PhD 《Journal of magnetic resonance imaging : JMRI》2009,30(4):737-742
Purpose
To demonstrate 4.7 Tesla (T) imaging methods for visualizing lesions in multiple sclerosis in the human brain using phase susceptibility‐weighting and T2 weighting.Materials and Methods
Seven patients with relapsing‐remitting multiple sclerosis were imaged at 4.7T using three‐dimensional (3D) susceptibility‐weighted imaging (SWI) with 0.90 mm3 voxel volumes, and with 2D T2‐weighted fast spin echo (T2WFSE) with 0.34 mm3 voxels and 1.84 mm3 voxels. The visibility of MS lesions at 4.7T with phase SWI and T2WFSE was assessed by independent lesion counts made by an experienced neuroradiologist, and by quantitative measures.Results
High resolution T2WFSE at 4.7T provided excellent depiction of hyperintense lesions. When combined with phase SWI, 124 total lesions were identified of which 18% were only visible on phase SWI and not on T2WFSE. The phase lesions had a mean phase shift relative to local background of ?11.15 ± 5.97 parts per billion.Conclusion
Imaging at 4.7T can provide both high quality, high resolution T2WFSE and SWI for visualization of lesions in multiple sclerosis. Phase susceptibility‐weighting can identify additional lesions that are not visible with high resolution T2WFSE. J. Magn. Reson. Imaging 2009;30:737–742. © 2009 Wiley‐Liss, Inc.13.
Toshitake Yakushiji PhD Kiyoshi Oka MD Hiro Sato MD Shigeta Yorimitsu MD Toru Fujimoto PhD Yasuyuki Yamashita PhD Hiroshi Mizuta PhD 《Journal of magnetic resonance imaging : JMRI》2009,29(4):895-900
Purpose
To detect differences in magnetic resonance imaging (MRI) between chondroblastic osteosarcoma and the other types of osteosarcomas or chondrosarcomas using gadolinium‐enhanced versus diffusion‐weighted sequences.Materials and Methods
Contrast‐enhanced MRI and diffusion‐weighted imaging (DWI) were performed in five chondroblastic osteosarcoma (CO) cases, 17 other types of osteosarcomas (OS), and 18 chondrosarcomas (CS). DWI was obtained with a single‐shot echo‐planar imaging (EPI) sequence using a 1.5T MR imager. The apparent diffusion coefficients (ADCs) of the minimum and maximum values were also obtained. The contrast‐enhancement pattern was evaluated and minimum‐maximum ADC value of CO was compared with other types of OS and CS.Results
Both CO and CS showed a similar enhancement pattern; both showed septonodular and peripheral rim enhancement. The minimum ADC value of CO (1.24 ± 0.10 × 10?3mm2/sec) was significantly higher than that of other types of OS (0.84 ± 0.15 × 10?3mm2/sec) and was significantly lower than that of CS (1.64 ± 0.20 × 10?3mm2/sec). In addition, the maximum ADC value of CO (2.28 ± 0.20 × 10?3mm2/sec) was significantly higher than that of other types of OS (1.33 ± 0.26 × 10?3mm2/sec).Conclusion
DWI appears to be more useful for differentiating between chondroblastic osteosarcoma and chondrosarcoma or other types of osteosarcoma than Gd‐enhanced MRI. J. Magn. Reson. Imaging 2009;29:895–900. © 2009 Wiley‐Liss, Inc.14.
Sung Hun Kim MD Eun Suk Cha MD Hyeon Sook Kim MD Bong Joo Kang MD Jae Jeong Choi MD Ji Han Jung MD Yong Gyu Park PhD Young Jin Suh MD 《Journal of magnetic resonance imaging : JMRI》2009,30(3):615-620
Purpose
To evaluate the role of diffusion‐weighted imaging (DWI) in the detection of breast cancers, and to correlate the apparent diffusion coefficient (ADC) value with prognostic factors.Materials and Methods
Sixty‐seven women with invasive cancer underwent breast MRI. Histological specimens were analyzed for tumor size and grade, and expression of estrogen receptors (ER), progesterone receptors, c‐erbB‐2, p53, Ki‐67, and epidermal growth factor receptors. The computed mean ADC values of breast cancer and normal breast parenchyma were compared. Relationships between the ADC values and prognostic factors were determined using Wilcoxon signed rank test and Kruskal‐Wallis test.Results
DWI detected breast cancer as a hyperintense area in 62 patients (92.5 %). A statistically significant difference in the mean ADC values of breast cancer (1.09 ± 0.27 × 10?5 mm2/s) and normal parenchyma (1.59 ± 0.27 × 10?5 mm2/s) was detected (P < 0.0001). There were no correlations between the ADC value and prognostic factors. However, the median ADC value was lower in the ER‐positive group than the ER negative group, and this difference was marginally significant (1.09 × 10?5 mm2/s versus 1.15 × 10?5 mm2/s, P = 0.053).Conclusion
The ADC value was a helpful parameter in detecting malignant breast tumors, but ADC value could not predict patient prognosis. J. Magn. Reson. Imaging 2009;30:615–620. © 2009 Wiley‐Liss, Inc.15.
Christina Schraml MD Nina F. Schwenzer MD Stephan Clasen MD Hans‐Joerg Rempp MD Petros Martirosian MS Claus D. Claussen MD Philippe L. Pereira MD 《Journal of magnetic resonance imaging : JMRI》2009,29(6):1308-1316
Purpose
To evaluate diffusion alterations after hepatic radiofrequency (RF) ablation using a navigator respiratory‐triggered diffusion‐weighted imaging (NRT‐DWI) sequence with regard to potential diagnostic information for detection of local tumor progression (LTP).Materials and Methods
One hundred forty‐eight consecutive follow‐up magnetic resonance (MR) examinations of 54 patients after hepatic RF ablation were reviewed. Apparent diffusion coefficient (ADC) values of ablation zones and liver parenchyma were assessed using a single‐shot echoplanar imaging sequence with the NRT technique. ADC values of ablation zones and adjacent signal alterations identified in NRT‐DWI were analyzed with regard to LTP.Results
Mean ADC values of ablation zones (119.9 ± 30.5 × 10?5 mm2/sec) and liver (106.3 ± 21.2 × 10?5 mm2/sec) differed significantly (P = 0.0003). No evident changes in ablations' ADC values over time could be identified. ADC values obtained from the entire ablation zone did not significantly differ regarding the presence of LTP. In 58 examinations, hyperintense areas in the periphery of the ablation zone were detected on the NRT‐DWI. Corresponding ADC values were significantly lower in patients with LTP (102.1 ± 22.4 versus 130.8 ± 47.6 × 10?5 mm2/sec; P = 0.0124).Conclusion
NRT‐DWI is useful in the follow‐up imaging after RF ablation. ADC‐based evaluation of signal alterations adjacent to the ablation zone may contribute to the identification of LTP and nontumoral posttreatment tissue changes. J. Magn. Reson. Imaging 2009. © 2009 Wiley‐Liss, Inc.16.
Michael A. Jacobs PhD Ronald Ouwerkerk PhD Ihab Kamel MD PhD Paul A. Bottomley PhD David A. Bluemke MD PhD Hyun S. Kim MD 《Journal of magnetic resonance imaging : JMRI》2009,29(3):649-656
Purpose
To determine the feasibility of using combined proton (1H), diffusion‐weighted imaging (DWI), and sodium (23Na) magnetic resonance imaging (MRI) to monitor the treatment of uterine leiomyomata (fibroids).Materials and Methods
Eight patients with uterine leiomyomata were enrolled and treated using MRI‐guided high‐intensity frequency ultrasound surgery (MRg‐HIFUS). MRI scans collected at baseline and posttreatment consisted of T2‐, T1‐, and 1H DWI, as well as posttreatment 23Na MRI. The 23Na and 1H MRi were coregistered using a replacement phantom method. Regions of interest in treated and untreated uterine leiomyoma tissue were drawn on 1H MRI and DWI, wherein the tissue apparent diffusion coefficient of water (ADC) and absolute sodium concentrations were measured.Results
Regions of treated uterine tissue were clearly identified on both DWI and 23Na images. The sodium concentrations in normal myometrium tissue were 35.8 ± 2.1 mmol (mM), in the fundus; 43.4 ± 3.8 mM, and in the bladder; 65.3 ± 0.8 mM with ADC in normal myometrium of 2.2 ± 0.3 × 10?3mm2/sec. Sodium concentration in untreated leiomyomata were 28 ± 5 mM, and were significantly elevated (41.6 ± 7.6 mM, P < 0.05) after treatment. Apparent diffusion coefficient values in the treated leiomyomata (1.30 ± 0.38 × 10?3 mm2/sec) were decreased compared to areas of untreated leiomyomata (1.75 ± ‐4048μ‐4050μ36 × 10?3 mm2/sec; P = 0.04).Conclusion
Multiparametric imaging permits identification of uterine leiomyomata, revealing altered 23Na MRI and DWI levels following noninvasive treatment that provides a mechanism to explore the molecular and metabolic pathways after treatment. J. Magn. Reson. Imaging 2009;29:649–656. © 2009 Wiley‐Liss, Inc.17.
Wei Feng Xiong MD Shi Jun Qiu PhD Hong Zhuo Wang MD Xiao Fei Lv MD 《Journal of magnetic resonance imaging : JMRI》2013,37(1):101-108
Purpose:
To detect radiation‐induced changes of temporal lobe normal‐appearing white mater (NAWM) following radiation therapy (RT) for nasopharyngeal carcinoma (NPC).Materials and Methods:
Seventy‐five H1‐MR spectroscopy and diffusion‐tensor imaging (DTI) examinations were performed in 55 patients before and after receiving fractionated radiation therapy (total dose; 66–75GY). We divided the dataset into six groups, a pre‐RT control group and five other groups based on time after completion of RT. N‐acetylaspartic acid (NAA)/choline (Cho), NAA/creatine (Cr), Cho/Cr, mean diffusibility (MD), functional anisotropy (FA), radial diffusibility (λ?), and axial diffusibility (λ||) were calculated.Results:
NAA/Cho and NAA/Cr decreased and λ? increased significantly within 1 year after RT compared with pre‐RT. After 1 year, NAA/Cho, NAA/Cr, and λ? were not significantly different from pre‐RT. In all post‐RT groups, FA decreased significantly. λ|| decreased within 9 months after RT compared with pre‐RT, but was not significantly different from pre‐RT more than 9 months after RT.Conclusion:
DTI and H1‐MR spectroscopy can be used to detect early radiation‐induced changes of temporal lobe NAWM following radiation therapy for NPC. Metabolic alterations and water diffusion characteristics of temporal lobe NAWM in patients with NPC after RT were dynamic and transient. J. Magn. Reson. Imaging 2013;37:101–108. © 2012 Wiley Periodicals, Inc.18.
Ahmed Abdel Razek MD Ahmed Elmorsy MD Mohsen Elshafey MD Tamer Elhadedy MD Osama Hamza MD 《Journal of magnetic resonance imaging : JMRI》2009,30(3):535-540
Purpose
To assess the role of diffusion‐weighted single‐shot echo‐planar magnetic resonance imaging (MRI) in patients with mediastinal tumors.Methods
Prospective study was conducted on 45 consecutive patients (29 male, 16 female, age 22–66 years, mean 41 years) with mediastinal tumor. They underwent diffusion‐weighted single‐shot echo‐planar MRI of the mediastinum with a b‐factor of 0, 300, and 600 sec/mm2. The apparent diffusion coefficient (ADC) value of the mediastinal tumor was correlated with the histopathological findings.Results
The mean ADC value of malignant mediastinal tumors was 1.09 ± 0.25 × 10?3 mm2/sec, and of benign tumors was 2.38 ± 0.56 × 10?3 mm2/sec. There was a significant difference in the mean ADC value between malignant and benign tumors (P = 0.001) and within different grades of malignancy (0.001). When an ADC value of 1.56 × 10?3 mm2/sec was used as a threshold value for differentiating malignant from benign tumor, the best results were obtained with an accuracy of 95%, sensitivity of 96%, specificity of 94%, positive predictive value of 94%, negative predictive value of 96%, and area under the curve of 0.938.Conclusion
The ADC value is a noninvasive parameter that can be used for differentiation of malignant from benign mediastinal tumors and grading of mediastinal malignancy. J. Magn. Reson. Imaging 2009. © 2009 Wiley‐Liss, Inc.19.
Thomas C. Kwee MD Craig J. Galbán PhD Christina Tsien MD Larry Junck MD Pia C. Sundgren MD PhD Marko K. Ivancevic PhD Timothy D. Johnson PhD Charles R. Meyer PhD Alnawaz Rehemtulla PhD Brian D. Ross PhD Thomas L. Chenevert PhD 《Journal of magnetic resonance imaging : JMRI》2010,31(3):531-537
Purpose:
To compare apparent diffusion coefficients (ADCs) with distributed diffusion coefficients (DDCs) in high‐grade gliomas.Materials and Methods:
Twenty patients with high‐grade gliomas prospectively underwent diffusion‐weighted MRI. Traditional ADC maps were created using b‐values of 0 and 1000 s/mm2. In addition, DDC maps were created by applying the stretched‐exponential model using b‐values of 0, 1000, 2000, and 4000 s/mm2. Whole‐tumor ADCs and DDCs (in 10?3 mm2/s) were measured and analyzed with a paired t‐test, Pearson's correlation coefficient, and the Bland‐Altman method.Results:
Tumor ADCs (1.14 ± 0.26) were significantly lower (P = 0.0001) than DDCs (1.64 ± 0.71). Tumor ADCs and DDCs were strongly correlated (R = 0.9716; P < 0.0001), but mean bias ± limits of agreement between tumor ADCs and DDCs was ?0.50 ± 0.90. There was a clear trend toward greater discordance between ADC and DDC at high ADC values.Conclusion:
Under the assumption that the stretched‐exponential model provides a more accurate estimate of the average diffusion rate than the mono‐exponential model, our results suggest that for a little diffusion attenuation the mono‐exponential fit works rather well for quantifying diffusion in high‐grade gliomas, whereas it works less well for a greater degree of diffusion attenuation. J. Magn. Reson. Imaging 2010;31:531–537. © 2010 Wiley‐Liss, Inc.20.
Jing Liu PhD Oliver Wieben PhD Youngkyoo Jung PhD Alexey A. Samsonov PhD Scott B. Reeder MD PhD Walter F. Block PhD 《Journal of magnetic resonance imaging : JMRI》2010,32(2):434-440