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1.
Introduction Distinguishing between vasogenic edema and reactive astrogliosis may be difficult in some instances. This study was performed
to test the hypothesis that diffusion-weighted (DW) imaging with apparent diffusion coefficient (ADC) maps can be used to
differentiate these two types of changes.
Methods The study population included 11 patients with perilesional vasogenic edema and 11 patients with gliosis examined with conventional
MR imaging and DW imaging. The signal intensities of conventional pulse sequences and ADC values were calculated in regions
of interest placed in the hyperintense edematous or gliotic regions and compared with those of normal-appearing white matter.
Signal intensity ratios and ADC values in gliosis were compared with those in vasogenic edema using the Mann-Whitney U-test.
Results While considerable overlap was present for signal intensity ratios on conventional MR images, areas of gliosis demonstrated
significantly higher ADC values (1.76 ± 0.09 × 10−3 mm2/s) than areas of vasogenic edema (1.35 ± 0.06 × 10−3 mm2/s; P < 0.0001) without overlap.
Conclusion ADC values are helpful in differentiating reactive gliosis from vasogenic edema. 相似文献
2.
Fujii S Matsusue E Kigawa J Sato S Kanasaki Y Nakanishi J Sugihara S Kaminou T Terakawa N Ogawa T 《European radiology》2008,18(2):384-389
Our purpose is to evaluate the diagnostic accuracy of apparent diffusion coefficient (ADC) measurement in differentiating
malignant from benign uterine endometrial cavity lesions. We retrospectively evaluated 25 uterine endometrial cavity lesions
in 25 female patients: endometrial carcinoma (n = 11), carcinosarcoma (n = 2), submucosal leiomyoma (n = 8), and endometrial
polyp (n = 4). Diffusion-weighted images were performed at 1.5 T with b factors of 0–1,000/mm2. The region of interest was defined within the tumor on T2-weighted EPI image and then manually copied to an ADC map. Thereby,
the ADC value was obtained. We compared ADC values between malignant and benign lesions using Student’s t-test. The mean and
standard deviation of ADC values (×10−3 mm2/s) were as follows: endometrial carcinoma, 0.98±0.21; carcinosarcoma, 0.97±0.02; submucosal leiomyoma, 1.37±0.28; and endometrial
polyp, 1.58±0.45. The ADC values differed significantly between malignant (0.98±0.19) and benign lesions (1.44±0.34) (P < 0.01).
We defined malignant tumors as cases with an ADC value less than 1.15 × 10−3 mm2/s for obtaining the highest accuracy. Sensitivity, specificity, and accuracy were 84.6%, 100%, and 92%, respectively. ADC
measurement can provide useful information in differentiating malignant from benign uterine endometrial cavity lesions. 相似文献
3.
Gourtsoyianni S Papanikolaou N Yarmenitis S Maris T Karantanas A Gourtsoyiannis N 《European radiology》2008,18(3):486-492
The purpose of this study was to measure apparent diffusion coefficient values of normal liver parenchyma and focal liver
lesions utilizing a respiratory gated diffusion sequence with multiple b-values and to investigate whether apparent diffusion
coefficient (ADC) measurements may be utilized to characterize and differentiate between malignant and benign focal hepatic
lesions. Thirty-eight consecutive patients underwent MRI of the liver including diffusion-weighted imaging (DWI). A single-shot
echo planar imaging sequence was applied in coronal orientation with multiple b-values (0, 50, 500, 1,000 s/mm2) and respiratory gating. ADC values were recorded on corresponding maps utilizing region of interest measurements in patients
with benign (group A), malignant (group B) focal lesions and liver parenchyma (group C). Statistical analysis was applied
to check whether differences in mean ADC values were significant (p<0.05). No focal lesions were detected in 11 patients,
with a mean ADC value (CI 95%) of liver parenchyma 1.25×10−3 mm2/s (1.21×10−3 mm2/s−1.29×10−3 mm2/s). Differences in mean ADC of liver parenchyma between group A and B were not significant (p=0.054, 1.30×10−3 mm2/s and 1.31×10−3 mm2/s, respectively). Mean ADC value (95% CI) of 22 benign lesions found in 18 patients was 2.55×10−3 mm2/s (2.35×10−3 mm2/s−2.74×10−3 mm2/s), while the mean ADC value (95% CI) of 16 malignant lesions recorded in 9 patients was 1.04×10−3 mm2/s (0.9×10−3 mm2/s−1.17×10−3 mm2/s). The difference between mean ADC values of benign and malignant focal lesions was statistically significant (p<0.0001).
Respiratory gated diffusion-weighted imaging in the liver is technically feasible. Apparent diffusion coefficient measurements
can be useful in differentiating malignant from benign focal liver lesions. 相似文献
4.
Pasco A Ter Minassian A Chapon C Lemaire L Franconi F Darabi D Caron C Benoit JP Le Jeune JJ 《European radiology》2006,16(7):1501-1508
The distinction between intracellular (ICE) and extracellular edema (ECE) has a crucial prognostic and therapeutic importance
in patients with severe traumatic brain injury (STBI). Indeed, ICE usually leads to cellular death, and maintenance of a cerebral
perfusion pressure (CPP) above 70 mmHg is still under debate since this practice may increase ECE. The purpose of this study
was to describe the ECE and ICE kinetics associated with STBI using quantitative diffusion MRI. Twelve patients were prospectively
studied. The initial ADC in ICE measured on day 1.3±0.7 is significantly reduced compared to normal-appearing parenchyma (0.51±0.12
* 10−3 mm2/s vs. 0.76±0.03 * 10−3 mm2/s, n=12, P<0.0001) and reaches normality on MRI 3 performed on day 14.2±3.3. In patients presenting an extension of ICE on MRI 2 performed
on day 6.7±1.4 (ADCMRI2=0.40±0.11 * 10−3 mm2/s), ADC values in the extension area at the first MRI were slightly, but not significantly reduced compared to normal parenchyma
(0.69±0.05 * 10-3 mm2/s, P=0.29). Normalization occurred equally by day 14. ADC in ECE (1.34±0.22 * 10−3 mm2/s) was elevated and stable with time under CPP therapy. Therefore, ECE is not worsened by CCP therapy, and ICE appears more
relevant than ECE in STBI. 相似文献
5.
The purpose was to investigate the potential value of apparent diffusion coefficient (ADC) measurement with MRI in the assessment
of cervix cancer. Diffusion-weighted MRI was performed in 47 patients with cervical carcinoma undergoing chemoradiation therapy
and 26 normal controls on a 1.5-T system with a b-value of 600 s/mm2. FIGO stage, tumor volume, nodal status, interstitial fluid pressure (IFP) and oxygen measurements were recorded. Response
was defined as no visible tumor 3–6 months following completion of therapy. The average median ADC (mADC) of cervical carcinomas
(1.09±0.20×10−3 mm2/s) was significantly lower than normal cervix (2.09±0.46×10−3 mm2/s) (P<0.001). There was no correlation between mADC, nodal status, tumor volume, IFP or oxygen measurements. mADC was significantly
lower in FIGO stages T1b/T2a (0.986 × 10−3 mm2/s) compared to T2b (1.21×10−3 mm2/s) and T3/T4 (1.10×10−3 mm2/s) (P<0.001). In patients with squamous carcinomas the 90th percentile of ADC values was lower in responders than non-responders
(P<0.05). Median ADC in cervix carcinoma is significantly lower compared to normal cervix. ADC may have predictive value in
squamous tumors, but further long-term study will determine the ultimate clinical utility. 相似文献
6.
We evaluated the diagnostic ability of diffusion-weighted imaging for the differentiation between lymphomas and carcinomas
in the pharynx and between carcinomas with different histological types in the pharynx. T1-weighted, fat-suppressed T2-weighted,
and diffusion-weighted MR imaging was performed on 14 patients with pharyngeal lymphomas, 26 patients with carcinomas of the
pharynx, 5 patients with adenoidal hypertrophy, and 22 patients with normal tonsils. Apparent diffusion coefficients (ADCs)
were determined by using two b factors (500 and 1,000 s/mm2). The ADCs of lymphomas were significantly smaller (0.454 ± 0.075 × 10−3 mm2/s) than those of carcinomas (0.863 ± 0.238 × 10−3 mm2/s). The ADCs of poorly differentiated and undifferentiated carcinomas (0.691 ± 0.149 × 10−3 mm2/s) were significantly smaller than those of moderately differentiated and well-differentiated carcinomas (0.971 ± 0.221 × 10−3 mm2/s), but were significantly larger than those of lymphomas. When an ADC smaller than 0.560 × 10−3 mm2/s was used for predicting lymphomas, we obtained the highest accuracy of 96%, with 100% sensitivity and 94% specificity,
86% positive predictive value, and 100% negative predictive value. Therefore, ADC measurements effectively differentiate lymphomas
from carcinomas in the pharynx and could be a useful adjunct to biopsy-based development of treatment planning. 相似文献
7.
Role of diffusion-weighted MR imaging in cervical lymphadenopathy 总被引:21,自引:0,他引:21
Abdel Razek AA Soliman NY Elkhamary S Alsharaway MK Tawfik A 《European radiology》2006,16(7):1468-1477
The role of diffusion-weighted magnetic resonance imaging (MRI) for differentiation between various causes of cervical lymphadenopathy
was evaluated. In a prospective study, 31 untreated patients (22 males and nine females, aged 5–70 years) with 87 cervical
lymph nodes underwent diffusion-weighted MRI before performance of neck dissection (n=14), surgical biopsy (n=9) or core biopsy (n=8). Diffusion-weighted MR images were acquired with a b factor of 0 and 1,000 s/mm2 using single-shot echo-planar sequence. Apparent diffusion coefficient (ADC) maps were reconstructed for all patients. The
signal intensity of the lymph nodes was assessed on images obtained at b=0 or 1,000 s/mm2 and from the ADC maps. The ADC value of lymph nodes was also calculated. On the ADC map, malignant nodes showed either low
(n=52) or mixed (n=20) signal intensity and benign nodes revealed high (n=13) or low (n=2) signal intensity. The mean ADC value of metastatic (1.09±0.11×10−3 mm2/s) and lymphomatous (0.97±0.27×10−3 mm2/s) lymph nodes was significantly lower than that of benign (1.64±0.16×10−3 mm2/s) cervical lymph nodes (P<0.04). When an ADC value of 1.38×10−3 mm2/s was used as a threshold value for differentiating malignant from benign lymph nodes, the best results were obtained with
an accuracy of 96%, sensitivity of 98%, specificity of 88%, positive predictive value of 98.5% and negative predictive value
of 83.7%. The smallest detected lymph node was 0.9 cm. In conclusion, diffusion-weighted MRI with ADC mapping is a new promising
technique that can differentiate malignant from benign lymph nodes and delineate the solid viable part of the lymph node for
biopsy. This technique provides additional useful physiological and functional information regarding characterization of cervical
lymph nodes. 相似文献
8.
Diffusion-weighted MRI in cystic or necrotic intracranial lesions 总被引:11,自引:2,他引:9
Our purpose was to investigate the signal intensities of cystic or necrotic intracranial lesions on diffusion-weighted MRI
(DWI) and measure their apparent diffusion coefficients (ADC). We examined 39 cystic or necrotic intracranial lesions in 33
consecutive patients: five malignant gliomas, seven metastases, two other necrotic tumours, a haemangioblastoma, three epidermoids,
an arachnoid cyst, seven pyogenic abscesses, 12 cases of cysticercosis and one of radiation necrosis. DWI was performed on
a 1.5 T unit using a single-shot echo-planar spin-echo pulse sequence with b 1000 s/mm2. The signal intensity of the cystic or necrotic portion on DWI was classified by visual assessment as markedly low (as low
as cerebrospinal fluid), slightly lower than, isointense with, and slightly or markedly higher than normal brain parenchyma.
ADC were calculated in 31 lesions using a linear estimation method with measurements from b of 0 and 1000 s/mm2. The cystic or necrotic portions of all neoplasms (other than two metastases) gave slightly or markedly low signal, with
ADC of more than 2.60 × 10−3 mm2/s. Two metastases in two patients showed marked high signal, with ADC of 0.50 × 10−3 mm2/s and 1.23 × 10−3 mm2/s, respectively. Epidermoids showed slight or marked high signal, with ADC of less than 1.03 × 10−3 mm2/s. The arachnoid cyst gave markedly low signal, with ADC of 3.00 × 10−3 mm2/s. All abscesses showed marked high signal, with ADC below 0.95 × 10−3 mm2/s. The cases of cysticercosis showed variable signal intensity; markedly low in five, slightly low in three and markedly
high in four.
Received: 17 November 1999/Accepted: 3 February 2000 相似文献
9.
L. Rizzo S. Greco Crasto P. Garcia Moruno P. Cassoni R. Rudà R. Boccaletti M. Brosio R. De Lucchi C. Fava 《La Radiologia medica》2009,114(4):645-659
Purpose This study was undertaken to correlate apparent diffusion coefficient (ADC) and relative regional cerebral blood volume (rrCBV)
to histological findings in a large series of patients with primary or secondary brain tumours to evaluate diffusion-weighted
(DWI) and perfusionweighted (PWI) imaging in the characterisation of cerebral tumors.
Materials and methods Ninety-eight patients with cerebral tumours, 46 of which were primary (seven grade 0-I, nine low-grade gliomas, two gliomatosis
cerebri, nine lymphomas and 19 high-grade gliomas) and 52 secondary, underwent conventional magnetic resonance (MR) imaging
completed with DWI and dynamic contrast susceptibility PWI. Both ADC and rrCBV were calculated on a workstation by using Functool
2 software. Student’s t test was used to determine any statistically significant differences in the ADC and rrCBV values.
Results Seventeen of 98 tumours were cystic or necrotic (12/17 hypointense and 5/17 hyperintense on DWI); the ADC value of hyperintense
cystic areas was 0.97±0.23×10−3 mm2/s. The ADC value of solid tumours varied between 0.64 and 3.5×10−3 mm2/s. The rrCBV value was 1.4 (σ 0.66) in low-grade gliomas; 1.22 (σ 0.25) in lymphomas; 4.5 (σ 0.85) in grade III gliomas;
3.18 (σ 1.26) in grade IV gliomas and 2.53 (σ 1.6) in metastases.
Conclusions DWI has an important role in the differential diagnosis of cystic cerebral masses but not in tumour characterisation. PWI
is helpful in differentiating high-from low-grade gliomas and lymphomas from high-grade gliomas.
相似文献
10.
Sener RN 《European radiology》2000,10(9):1452-1455
A patient is reported with diffuse leukoencephalopathy associated with cystic degeneration of the white matter of the brain
(van der Knaap syndrome). The changes were studied by fluid attenuated inversion recovery (FLAIR), and diffusion-weighted
MR imaging. The FLAIR sequence revealed suppressed signal of the cysts, and widespread high-signal white matter changes associated
with thinned cortices. On diffusion-weighted MR imaging, apparent diffusion coefficient (ADC) values ranged from 3.0 × 10–3 to 2.7 × 10–3 mm2/s in the temporal cysts, similar to that of CSF. The ADC values within the parenchyma ranged between 2 × 10–3 and 2.1 × 10–3 mm2/s, a value falling between normal parenchyma and cerebrospinal fluid, compared with a control group of three healthy subjects.
The changes were also evaluated by proton MR spectroscopy, and were compared with a control group of 12 cases. Magnetic resonance
spectroscopy revealed apparently increased NAA/Cr ratios in most parts of the brain. The NAA/Cho ratios were either high or
low, and the Cho/Cr ratios were increased or normal in different regions.
Received: 27 October 1999; Revised: 9 December 1999; Accepted: 20 December 1999 相似文献
11.
Reiji Sugita Tetsuro Yamazaki Akemi Furuta Kei Itoh Naotaka Fujita Shoki Takahashi 《European radiology》2009,19(7):1794-1798
The aim of this preliminary study was to retrospectively evaluate the usefulness of high b-value diffusion-weighted MR imaging
(DWI) in the detection of gallbladder carcinoma. Fifteen patients with gallbladder carcinoma and 14 other patients were included
in this study. All patients and subjects underwent DWI, and images were evaluated by two radiologists. The area under the
receiver operating characteristic curve (AUC), apparent diffusion coefficient (ADC) measurement, sensitivity and specificity
were calculated. An AUC yielded 0.980 (95% CI, 0.850–0.999) and 0.941 (95% CI, 0.791–0.990) for the two radiologists. The
mean sensitivity and specificity were 83.3% and 100%, respectively. The mean ADC value of gallbladder carcinoma was (1.28 ± 0.41)×10−3 mm2/s and that of control gallbladder lesions was (1.92 ± 0.21)×10−3 mm2/s (P < 0.01). According to the results of our preliminary study, high b-value DWI might be a useful tool for detecting gallbladder
carcinoma by measuring the ADC value and direct visual assessment. 相似文献
12.
The aim of this study was to retrospectively measure and compare pancreatic apparent diffusion coefficient (ADC) in patients
with acute pancreatitis (AP) with aged matched controls who underwent diffusion weighted imaging (DWI). The institutional
review board approved this retrospective Health Insurance Portability and Accountability Act compliant study with a waiver
for informed consent. Pancreatic ADC values from 27 patients with a clinical diagnosis of AP and 38 normal age-matched controls
evaluated with DWI (b = 0 and 800 mm2/s) were retrospectively and independently measured by two radiologists. The ADCs were compared between the groups and between
each of the pancreatic segments in the normal group. Inter-observer reliability was calculated and receiver operating characteristic
analysis was used to determine the sensitivity and specificity of DW imaging in the diagnosis of acute pancreatitis. P < 0.05 was considered statistically significant. The ICC for inter-observer reliability was 0.98 in the control and 0.97
in the AP group. The mean pancreatic ADC in the AP group (1.32 × 10−3 mm2/s ± 0.13) was significantly lower than in the normal group (1.77 × 10−3 mm2/s ± 0.32). There was no significant difference in mean ADCs between each of the pancreatic segments in the controls. A threshold
ADC value of 1.62 × 10–3 mm2/s yielded a sensitivity of 93% and specificity of 87% for detecting acute pancreatitis for b values of 0 and 800 s/mm2. Pancreatic ADCs are significantly lower in patients with AP than normal controls. 相似文献
13.
Ohgiya Y Oka M Hiwatashi A Liu X Kakimoto N Westesson PL Ekholm SE 《European radiology》2007,17(10):2499-2504
Our purpose was to evaluate the ability of diffusion tensor imaging (DTI) to characterize cervical spinal cord white matter
(WM) in patients with multiple sclerosis (MS). DTI were obtained in 21 MS patients and 21 control subjects (CS). Regions of
interest (ROIs) were placed at C2/3, C3/4, and C4/5 within the right, left, and dorsal (WM) to calculate fractional anisotropy
(FA) and the apparent diffusion coefficient (ADC). Measurements in plaques and normal-appearing white matter (NAWM) of MS
patients were compared with mean FA and ADC of WM in CS. FA was significantly lower in all regions in MS patients than in
CS. ADC was significantly higher in all regions in MS patients than in CS except for in the dorsal WM at C2/3 and the bilateral
WM at C4/5. The mean FA was 0.441 for plaques and 0.542 for NAWM, as compared with 0.739 in CS. The mean ADC was 0.810 × 10−3 mm2/s for plaques and 0.722 × 10−3 mm2/s for NAWM, as compared with 0.640 ×10−3 mm2/s for CS. FA and ADC showed significant differences between plaques, NAWM and control WM(P < 0.01). 相似文献
14.
Abdel Razek AA Gaballa G Elhawarey G Megahed AS Hafez M Nada N 《European radiology》2009,19(1):201-208
We aimed to assess the clinical usefulness of the ADCs calculated from diffusion-weighted echo-planar MR images in the characterization
of pediatric head and neck masses. This study included 78 pediatric patients (46 boys and 32 girls aged 3 months–15 years,
mean 6 years) with head and neck mass. Routine MR imaging and diffusion-weighted MR imaging were done on a 1.5-T MR unit using
a single-shot echo-planar imaging (EPI) with a b factor of 0.500 and 1,000 s mm−2. The ADC value was calculated. The mean ADC values of the malignant tumours, benign solid masses and cystic lesions were
(0.93 ± 0.18) × 10−3, (1.57 ± 0.26) × 10–3 and (2.01 ± 0.21 )× 10–3 mm2 s−1, respectively. The difference in ADC value between the malignant tumours and benign lesions was statistically significant
(p < 0.001). When an apparent diffusion coefficient value of 1.25 × 10–3 mm2 s−1 was used as a threshold value for differentiating malignant from benign head and neck mass, the best results were obtained
with an accuracy of 92.8%, sensitivity of 94.4%, specificity of 91.2%, positive predictive value of 91% and negative predictive
value of 94.2%. Diffusion-weighted MR imaging is a new promising imaging approach that can be used for characterization of
pediatric head and neck mass. 相似文献
15.
Aine Sakurada Taro Takahara Thomas C. Kwee Tomohiro Yamashita Seiji Nasu Tomohiko Horie Marc Van Cauteren Yutaka Imai 《European radiology》2009,19(6):1461-1469
The purpose of this study was to assess the value of diffusion-weighted magnetic resonance imaging (DWI) in detecting esophageal
cancer and assessing lymph-node status, compared with histopathological results. DWI was prospectively performed in 24 consecutive
patients with esophageal cancer, using the diffusion-weighted whole-body imaging with background body signal suppression (DWIBS)
sequence. DWIBS images were fused with T2-weighted images, and independently and blindly evaluated by three board-certified
radiologists, regarding primary tumor detectability and lymph-node status. Apparent diffusion coefficients (ADCs) of the primary
tumor and lymph nodes were also measured. Average primary tumor detection rate was 49.4%, average patient-based sensitivity
and specificity for the detection of lymph-node metastasis were 77.8 and 55.6%, and average lymph-node group-based sensitivity
and specificity were 39.4 and 92.6%. There were no interobserver differences among the three readers (P < 0.0001). Mean ADC of detected primary tumors was 1.26 ± 0.29×10−3 mm2/s. Mean ADC of metastatic lymph nodes (1.46 ± 0.35×10−3 mm2/s) was significantly higher (P < 0.0001) than that of nonmetastatic lymph nodes (1.15 ± 0.24 mm2/s), but ADCs of both groups overlapped. In conclusion, this study suggests that DWI only has a limited role in detecting
esophageal cancer and nodal staging. 相似文献
16.
Role of diffusion-weighted echo-planar MRI in distinguishing between brain abscess and tumour: a preliminary report 总被引:13,自引:6,他引:7
Noguchi K Watanabe N Nagayoshi T Kanazawa T Toyoshima S Shimizu M Seto H 《Neuroradiology》1999,41(3):171-174
Our purpose was to evaluate diffusion-weighted (DW) echo-planar MRI in differentiating between brain abscess and tumour.
We examined two patients with surgically confirmed pyogenic brain abscess and 18 with metastatic brain tumours or high-grade
glioma, using a 1.5 T system. The apparent diffusion coefficient (ADC) of each necrotic or solid contrast-enhancing lesion
was measured with two different b values (20 and 1200 s/mm2). All capsule-stage brain abscesses (4 lesions) and zones of cerebritis (2 lesions) were identified on high-b-value DWI as
markedly high-signal areas of decreased ADC (range, 0.58–0.70 [(10–3 mm2/s; mean, 0.63)]). All cystic or necrotic portions of brain tumours (14 lesions) were identified on high-b-value DWI as low-signal
areas of increased ADC (range, 2.20–3.20 [(10–3 mm2/s; mean, 2.70)]). Solid, contrast-enhancing portions of brain tumours (19 lesions) were identified on high-b-value DWI as
high-signal areas of sightly decreased or increased ADC (range, 0.77–1.29 [(10–3 mm2/s; mean, 0.94)]). Our preliminary results indicate that DW echo-planar MRI be used for distinguishing between brain abscess
and tumour.
Received: 23 January 1998 Accepted: 5 June 1998 相似文献
17.
Introduction Epidural spinal cord compression is one of the most critical emergency conditions requiring medical attention and requires
prompt and adequate treatment. The aim of our study was to assess the role of diffusion-weighted magnetic resonance (MR) imaging
(DWI) in the diagnosis and differentiation of epidural spinal lesions.
Methods Three patients with epidural lymphoma, two with sarcoma and three with epidural metastatic disease were imaged on a 1.5T MRI
unit. DWI was performed using navigated, interleaved, multi-shot echo planar imaging (IEPI). Three region of interest (ROI)-measurements
were obtained on corresponding apparent diffusion coefficient (ADC) maps, and the mean ADC value was used for further analysis.
The cellularity of tumors was determined as the N/C ratio (nucleus/cytoplasma ratio) from histological samples. The ADC values
and N/C ratios of lesions were compared using a Kruskal-Wallis test.
Results The mean ADC of the lymphomas was 0.66 × 10−3 mm2/s, that of the sarcomas was 0.85 × 10−3 mm2/s and the ADC of the metastatic lesions was 1.05 × 10−3 mm2/s; however, the differences were not statistically significant. Mean N/C ratios in the lymphoma, sarcomas and metastases
were 4:1, 2:1, and 2.6:1, respectively, with a statistically significant difference between the groups (p < 0.025).
Conclusion Although not statistically significant due to the small patient sample, our results clearly show a tendency toward decreased
diffusivity in neoplastic lesions with higher cellularity. The data from our study suggest that DWI is a feasible and potentially
useful technique for the evaluation of epidural lesions that cause spinal cord compression on a per-patient basis. 相似文献
18.
Bernard J. Dardzinski Christopher H. Sotak Ph.D. Marc Fisher Yasuhiro Hasegawa Lirnin Li Kazuo Minematsu 《Magnetic resonance in medicine》1993,30(3):318-325
Diffusion-weighted, echo-planar imaging (EPI) was used to map regional changes In the apparent diffusion coefficient (ADC) during experimental focal ischemia in the rat brain following permanent middle cerebral arterial occlusion (MCAO). Sixteen 64 × 64 diffusion-weighted EPIs were acquired in 32 s with successively increasing amplitudes of the diffusion-sensitive gradient pulses. A linear least-squares regression algorithm was used to fit 15 of the 16 two-dimensional matrices, on a pixel-by-pixel basis, to solve for the slope from which the ADC value was calculated. The correlation coefficient of the fit, R2 was used to filter the final ADC maps, and the ADCs were then scaled appropriately to be displayed in a 256 gray level format. Ranges (bins) of 0.05 × 10−3 mm2/s were then grouped and color coded to qualify and quantify the evolution of ischemia in the MCA territory. The percentage of area in the ischemic and contralateral hemispheres in seven ADC bins were calculated at 30, 60, and 120 min after MCAO for 10 animals and demonstrated a significant increase in ADC bins below 0.45 × 10−3 mm2/s and a decrease in bins above 0.50 × 10−3 mm2/s over the. The postmortem infarct area, as measured by TTC staining, was highly correlated with the portion of the ischemic hemisphere falling below ADC values of 0.55 × 10−3 mm2/s at 2 h after stroke onset. These studies suggest that focally ischemic brain tissue can be quantitatively subdivided according to ADC values and that ADC values below 0.55 × 10−3 mm2/s 2 h following ischemia highly predict infarction in a rat permanent occlusion stroke model. 相似文献
19.
Tomohiro Namimoto Yasuyuki Yamashita Kazuo Awai Takeshi Nakaura Yumi Yanaga Toshinori Hirai Tetsuo Saito Hidetaka Katabuchi 《European radiology》2009,19(11):2756-2764
The objective of our study was to compare diffusion-weighted imaging (DWI) alone and DWI combined with T2-weighted MRI for
the differentiation of uterine sarcomas from benign leiomyomas. T2-weighted imaging and DWI were performed in 103 patients
with 103 myometrial tumours, including 8 uterine sarcomas and 95 benign leiomyomas on 3-T MR imaging. The signal intensity
(SI) of the tumour on T2-weighted images was quantified as the tumour–myometrium contrast ratio (TCR) by using the following
formula: (SItumour − SImyometrium)/SImyometrium. The TCR or apparent diffusion coefficient (ADC) value alone and then the ADC value combined with T2-weighted imaging were
evaluated for differentiation between sarcomas and leiomyomas. The mean ADC value of sarcomas was 0.86 ± 0.11 × 10−3 m2/s, which was significantly lower than that of leiomyomas 1.18 ± 0.24 × 10−3 m2/s; however, there was a substantial overlap. The mean TCR of sarcomas was 0.66 ± 0.71, which was significantly higher than
that of the leiomyomas, –0.37 ± 0.34; however, again, there was a considerable overlap. When ADC was less than 1.05 × 10−3 mm2/s and TCR was greater than 0 this condition was considered to confirm a sarcoma; a combination of ADC and TCR achieved a
significant improvement without any overlap between sarcomas and leiomyomas (sensitivity 100%, specificity 100%). Our preliminary
results indicate that combined DWI and T2-weighted MR imaging is better than DWI alone in the differentiation of uterine sarcomas
from benign leiomyomas. 相似文献
20.
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