rADC Values Research Articles

Evaluation of placenta with relative apparent diffusion coefficient and relative T2 signal intensity analysis

We aimed to test the null hypothesis that relative apparent diffusion coefficient (rADC) and relative signal intensity values (rSI(HASTE)) do not change in the evaluation of placental maturation with advancing gestational age. Fifty-six fetuses with diffusion-weighted magnetic resonance imaging (DW-MRI) data were enrolled in this retrospective study. Fetuses were analyzed in three different gestational age groups: group 1, 18-23 weeks; group 2, 24-28 weeks; and group 3, 29-38 weeks. The rADC (mean ADC/ADC(globe)) and rSI(HASTE) values (mean SI(HASTE)/SI(globe)) were obtained. Two radiologists experienced in fetal MRI who were blinded to the patient information reviewed MRI images independently. Kruskal-Wallis Test was used to compare the rADC and rSI(HASTE) with gestational age groups. The agreement between the two blinded readers was tested using Krippendorff's alpha ratio. Both placental rADC values and placental rSI(HASTE) values were not significantly different between the gestational age groups (P = 0.688 and P = 0.280, respectively). rADC and rSI(HASTE) measurements were reproducible with a good agreement between the two readers (Krippendorff's alpha ratio was 0.613 and 0.778, respectively). The rADC and rSI(HASTE) values do not change with advancing gestational age.

Findings and Patterns on MRI and MR Spectroscopy in Neonates after Therapeutic Hypothermia for Hypoxic Ischemic Encephalopathy Treatment

The purpose of this study is to describe the findings and patterns of injury on magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) after whole-body hypothermia treatment for neonatal hypoxic ischemic encephalopathy. A retrospective review of consecutive term neonates treated with whole-body hypothermia was performed. Data recorded included demographics and MRI and MRS findings, and day of life (DOL) studies were performed. Injury patterns were classified on MRI as deep, cortical, mixed, or diffuse. The relative apparent diffusion coefficient (rADC) was plotted against DOL scanned and the presence of lactate was recorded. MRI was performed in 44 infants, 34 of whom also underwent MRS. MRI was abnormal in 32% of neonates, 29.5% of whom were imaged at DOL 4 to 8. rADC values were lowest in neonates scanned on DOL 4 and 5 and remained low up to DOL 8. The deep brain nuclei were involved in hypoxic ischemic encephalopathy in 93% of neonates with abnormal MRIs and lactate was identified on MRS in 18% of neonates between DOL 4 and 8. MRI performed after therapeutic cooling was abnormal in 29.5% of neonates scanned on DOL 4 to 8. Deep nuclear injury was identified in 93% of neonates. Lactate was present on MRS in 18% of neonates, and rADC values were most reduced on MRI between DOL 4 and 8.

The Course of Apparent Diffusion Coefficient Values following Perinatal Arterial Ischemic Stroke

BackgroundDiffusion weighted MR imaging (DWI) plays an important role in the diagnosis of perinatal arterial ischemic stroke (PAIS) during the acute phase. Its derived apparent diffusion coefficient (ADC) can be used to quantify the diffusion restriction. Aim of the current study was to identify the changes in ADC values in the acute phase following PAIS.MethodsA cohort of 36 infants with a confirmed PAIS who were examined once during the first ten days of life was studied. ADC values in the core of the ischemic tissue (iADC) were determined and correlated with postnatal age. ADC ratios (rADC) were calculated by dividing the iADC value by the ADC value of the corresponding area in the contralateral ‘healthy’ hemisphere.ResultsInfants were scanned between days two and ten. A non-linear increase in iADC and rADC values was observed over time and large middle cerebral artery strokes resulted in lower iADC and rADC values. Normalisation of rADC values was observed after day seven. rADC values were lower when compared to previously published rADC values of infants with hypoxic ischemic encephalopathy, suggesting more severe injury.ConclusionsFollowing PAIS, DWI showed decreased ADC values with a non-linear increase during the first week, and pseudonormalization after day 7, which limits the use of DWI to assess PAIS to the first week. Compared to previous studies, ADC values were lower when compared to infants with hypoxic ischemic encephalopathy, most likely due to more severe injury.

Quantitative Evaluation of Acupuncture Improvements in Patients with White Matter Infarction by Diffusion Tensor Imaging

Objective: To evaluate the effect of acupuncture in improving ischemic white matter in acute stroke patients by diffusion tensor imaging (DTI). Methods: Twelve acute unilateral cerebral ischemia patients underwent MRI and DTI studies within three days of the onset of the disease. Then they were randomly divided into an acupuncture treatment (AT) group (n=6) and a without acupuncture treatment (non‐AT) group (n=6). MRI and DTI scans were carried out one, two and three months after treatment. Fractional anisotropy (FA) maps, apparent diffusion coefficient (ADC) maps and diffuse tensor tracking (DTT) images were obtained. With reference to the DW images, regions of interest (ROIs) were selected on the ischemic white matter and control ROIs were selected on the contra‐lateral homonymic white matter. The ratios of FA and ADC (rFA and rADC) within these ROIs were calculated and compared. Results: The repeated two‐way ANOVA analysis showed there were significant differences in rFA (F=6.655, P=0.001) and rADC (F=19.136, P=0.000) values at the time of onset and one, two and three months after therapy among the two groups, respectively. It revealed significant differences in rADC values, both of AT (F=4.845, P=0.005) and non‐AT groups (F=12.575, P=0.000) and in the rFA values of the non‐AT group (F=3.852, P=0.015). The AT group rFA values (t=2.614,P=0.012) at onset were significantly higher than that at one month post‐treatment, while the rADC values (t=3.358, P=0.002) were lower. Significantly lower rADC values were found in the AT group at the onset of illness than two and three months of treatment later(t=2.936, P=0.005; t=3.199, P=0.002). The non‐AT group rFA values at onset (t=3.151, P=0.003)and one month post‐treatment (t=2.369, P=0.022) were significantly higher than those at two months post‐ treatment and the rADC values at onset were significantly lower than those of two and three months post‐treatment(t=5.372,P=0.000; t=4.702,P=0.000). Lower rADC values of the non‐AT group at one month post‐treatment were detected than at two and three months post treatment (t=3.473, P=0.001; t=2.974, P=0.005). Compared to the normal white matter tracts, DTT images showed the ischemic white matter tracts were sparse, 1 Shuohui Yang, Fang Lu, Weidong Pan, Zhigang Gong and Songhua Zhan: Quantitative Evaluation of Acupuncture Improvements in Patients with White Matter Infarction by Diffusion Tensor Imaging www.intechopen.com ARTICLE Int. j. integr. med., 2013, Vol. 1, 18:2013

Correlation of apparent diffusion coefficient with Ki-67 in the diagnosis of gliomas.

To study the correlation between apparent diffusion coefficient (ADC) and Ki-67, a marker of tumor activity, in the diagnosis of gliomas. Conventional magnetic resonance imaging (MRI), enhanced scanning, and diffusion-weighted imaging were performed in 76 patients with pathologically confirmed gliomas. The ADC values were measured at tumor parenchyma and the corresponding contralateral normal brain. The relatively ADC (rADC) values of the tumor parenchyma were calculated. The correlation of the ADC values with tumor grades was analyzed. The expression of Ki-67 was detected by immunohistochemical staining. The correlation between ADC value and Ki-67 in the diagnosis of gliomas was analyzed. The ADC values and rADC values of high-grade gliomas were significantly lower than those of low-grade gliomas. The ADC values of tumor parenchyma were inversely associated with the degree of malignancy of the gliomas (r=-0.898, r=-0.868; P<0.01). The expression of Ki-67 was significantly higher in high-grade gliomas than that in low-grade gliomas. The Ki-67 labeling index in grade 3 and 4 gliomas were (29.48 ± 19.78)% and (31.21 ± 17.50)%, respectively. Both of them were significantly higher than Ki-67 labeling index in low-grade (grade 1 and 2) gliomas [(2.33 ± 2.20)%] (P<0.01). Nevertheless, the Ki-67 labeling index showed no significant difference between grade 3 and 4 gliomas (P>0.05). The expression of Ki-67 was negatively correlated with the ADC values and rADC values in tumor parenchyma (r=-0.627, r=-0.607; P<0.01). The ADC and rADC values of tumor parenchyma can indirectly reflect the proliferation and malignancy of gliomas and therefore can be useful for the grading of glioma.

Temporal changes in perihematomal apparent diffusion coefficient values during the transition from acute to subacute phases in patients with spontaneous intracerebral hemorrhage

Diffusion-weighted imaging (DWI) studies focusing on apparent diffusion coefficient (ADC) abnormalities have provided conflicting results about the nature and fate of perihematomal edema. We investigated 35 patients with supratentorial spontaneous intracerebral hemorrhage (SICH) by using DWI scanning obtained at 48 h and 7 days after symptom onset. Regional ADC (rADC) values were measured in three manually outlined regions of interest: (1) the perihematomal hyperintense area, (2) 1 cm of normal appearing brain tissue surrounding the perilesional hyperintense rim, and (3) a mirror area, including the clot and the perihematomal region, located in the contralateral hemisphere. rADC mean levels were lower at 7 days than at 48 h in each ROI (p < 0.00001), showing a progressive normalization of initial vasogenic values. Perihematomal vasogenic rADC values were more frequent (p < 0.00001) at 48 h than at 7 days, whereas perihematomal cytotoxic and normal rADC levels were more represented (p < 0.02 and p < 0.001, respectively) at 7 days than at 48 h. A neurological worsening was more frequent (p < 0.02) in patients with than in those without perihematomal cytotoxic rADC values at 7 days. Our findings suggest that the transition from acute to subacute phases after SICH is characterized by a progressive resolution of perihematomal vasogenic edema associated with an increase in cytotoxic ADC values. In the subset of patients with perihematomal cytotoxic rADC levels in subacute stage after bleeding, irreversible damage development seems to be related to poor clinical outcome.

Abstract 2355: Assessment of glioma recurrence following radiotherapy using the parametric response map: A preclinical study

Abstract Heterogeneity of the glioblastoma multiforme (GBM) response to standard therapies can be due to spatially varying phenotypes within an individual tumor due to genomic instability. The goal of this study was to evaluate the parametric response map PRM, a voxel-based analytical approach, as a biomarker of tumor recurrence on an animal-by-animal basis in a radiation dose escalation protocol. Twenty-four genetically engineered murine GBM model [Ink4a/Arf-/- PtenloxP/loxp/ Ntv-a RCAS/PDGF(+)/Cre(+)] were imaged by MRI (contrast-enhanced (CE-T1w) and diffusion-weighted MRI) daily for a week and then every two days thereafter. Tumor bearing animals were introduced to the study (D0) when the tumors reached a volume of ∼20 mm3. Mice were randomized in 4 groups (n=6 per group): 0G and daily doses of 1G, 2G and 4G delivered daily for 5 days. Tumor volumes of interest (VOI) were manually contoured on the CE-T1w images and reported on the diffusion map. The relative ADC (rADC) maps were computed by normalized values using a VOI defined within the contralateral striatum. PRM was performed by calculating the difference in mid-treatment from pre-treatment rADC values for each voxel in the tumor. Voxels were classified, based on a user-defined threshold set at ±337 rADC units, as significantly increasing (PRMrADC+), significantly decreasing (PRMrADC-), and unchanged (PRMrADC0) rADC values following therapy. The volume fraction of each classification was calculated by summing the class specific voxels and normalizing by the tumor volume. Finally, for each animal the maximum PRMrADC+ value (maxPRMrADC+) was determined within the first 5 days following therapy initiation. The maxPRMrADC+ was correlated to time to recurrence using a linear regression (TTR; was defined as the time for the tumor to triple its initial volume at baseline (D0)). We observed a large inter- and intra-group variability of TTR (intra-group variability in day: [min-max] = [3-5], [3-9], [13-21] and [19-25] for the 0G, 1G, 2G and 4G groups; respectively). The day of the maxPRMrADC+ value measured animal by animal was somewhat variable over the week of treatment administration. We observed a linear increase of maxPRMrADC+ value which correlated with the dose of radiation received (from 4.5±2.7 % to 33.9±11.3 %; for control and 4G groups; respectively). We also found excellent correlation between TTR and the maxPRMrADC+ metric value of individual animals during the week of treatment (R2 = 0.85). This study demonstrates the efficacy of PRM as an imaging biomarker of tumor recurrence following radiotherapy. The maxPRMrADC+ values measured during radiation therapy were correlated strongly with TTR. PRMrADC technique may serve as a biomarker of tumor recurrence that is insensitive to the response heterogeneity typically observed in GBM. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2355. doi:1538-7445.AM2012-2355

Differentiation of axillary inflammatory and metastatic lymph nodes with diffusion-weighted imaging in animal modes

To evaluate the value of diffusion-weighted imaging (DWI) in the differentiation of axillary inflammatory hyperplastic and metastatic lymph nodes. Forty female New Zealand white rabbits were divided randomly into 2 groups (n = 20 each). And the animal models of axillary inflammatory hyperplastic and metastatic lymph nodes were established. All successfully implanted models received conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) examinations. The features of signal intensity and shapes of lymph nodes were observed in two groups. The sizes of lymph nodes were measured on the selected axial T(2)WI. The signal intensity and appearance diffusion coefficient (ADC) value of lymph nodes and dorsal muscle at the same slice were measured on the selected T(2)WI, DWI and ADC map respectively. The relative signal intensity (rSIT(2)WI, rSIDWI) and relative ADC (rADC) value of lymph nodes to dorsal muscle were calculated and compared. The diagnostic efficacy of differentiating benign and malignant lymph nodes was analyzed with rADC value through the receiver operating characteristic curve. The correlation between rADC value and cell density was assessed with pathological findings as reference standard. The differences of size, rSIT(2)WI and rSIDWI were not statistically significant between two groups. The rADC value of inflammatory lymph nodes was greater than that of metastatic lymph nodes (0.91 ± 0.14 vs 0.64 ± 0.18). Significant difference existed (t = 3.879, P = 0.03). But there was a little overlap between two groups. With 0.78 as the diagnostic threshold of rADC value, the sensibility and specificity was 86.2% and 74.4% respectively. The correlation between rADC value and cell density of inflammatory hyperplastic and metastatic lymph nodes was significantly inverse (r = -0.53, P = 0.003). As compared with the routine MRI sequence, rADC value has a higher diagnostic efficacy in the differentiation of benign and malignant lymph nodes. Cell density may be the most important influencing factor for the differences of rADC value between two groups of lymph nodes.

Significance of apparent diffusion coefficient measurement for the differential diagnosis of multiple system atrophy, progressive supranuclear palsy, and Parkinson's disease: evaluation by 3.0-T MR imaging

The clinical differentiation of Parkinson's disease (PD) from multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) may be challenging, especially in their early stages. The aim of this study was to evaluate the utility of apparent diffusion coefficient (ADC) measurement to distinguish among these degenerative disorders. Twenty-five MSA, 20 PSP, and 17 PD patients and 18 healthy controls were retrospectively studied. Axial diffusion-weighted and T2-weighted images were obtained using a 3-T MR system. Regions of interest (ROIs) were precisely placed in the midbrain, pons, putamen, globus pallidus, caudate nucleus, thalamus, superior cerebellar peduncle, middle cerebellar peduncle, cerebellar white matter, and cerebellar dentate nucleus, and the regional ADC (rADC) value was calculated in each ROI. In MSA, rADC values in the pons, middle cerebellar peduncle, cerebellar white matter, and cerebellar dentate nucleus were significantly higher than in PSP, PD, and controls. Furthermore, rADC values in the posterior putamen were significantly higher in MSA than in PSP and controls. In PSP, rADC values were significantly higher in the globus pallidus and midbrain than in MSA, PD, and controls. Furthermore, rADC values in the caudate nucleus and superior cerebellar peduncle were significantly higher in PSP than in MSA and controls. In PD, there were no significant differences in the rADC values compared to in MSA, PSP, and controls in all regions. Evaluation of rADC values in characteristic lesions in MSA, PSP, and PD by placing ROIs using 3-T systems can provide useful additional information for differentiating these disorders.

Differential Diagnosis of Axillary Inflammatory and Metastatic Lymph Nodes in Rabbit Models by Using Diffusion-Weighted Imaging: Compared with Conventional Magnetic Resonance Imaging

ObjectiveThis experiment aims to determine the diagnostic value of diffusion-weighted imaging (DWI) in the differentiation of axillary inflammatory lymph nodes from metastatic lymph nodes in rabbit models in comparison with conventional magnetic resonance imaging (MRI).Materials and MethodsConventional MRI and DWI were performed at 4 weeks after successful inoculation into the forty female New Zealand white rabbits' mammary glands. The size-based and signal-intensity-based criteria and the relative apparent diffusion coefficient (rADC) value were compared between the axillary inflammatory lymph nodes and metastatic lymph nodes, with histopathological findings as the reference standard. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of the aforementioned criteria and rADC value in differentiating the axillary inflammatory lymph nodes from metastatic lymph nodes.ResultsThirty-two axillary inflammatory lymph nodes and 46 metastatic ones were successfully isolated and taken into pathological analysis. The differences of the aforementioned criteria between the two groups were not statistically significant (p > 0.05). However, the rADC value of the inflammatory lymph nodes (0.9 ± 0.14) was higher than that of metastatic ones (0.7 ± 0.18), with significant difference (p = 0.016). When the rADC value was chosen as 0.80, the area under the ROC curve is greater than all other criteria, and the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for differentiating two groups were 86.2%, 79.3%, 81.2%, 84.2%, and 85.6%, respectively.ConclusionDiffusion-weighted imaging is a promising new technique for differentiating axillary inflammatory lymph nodes from metastatic lymph nodes. Compared with routine magnetic resonance sequences, DWI could provide more useful physiological and functional information for diagnosis.

The MRI study on the changes of lesion volume and ADC values of brainstem infarction and the correlation with clinical prognosis

Objective To explore the regular variation of lesion volume and apparent diffusion coefficient (ADC) value of brainstem infarction in different stages after stroke symptom onset, and analyse the correlation between infarction volume, ADC value and clinical prognosis. Methods Eleven patients with brainstem infarction underwent 5 magnetic resonance imaging (MRI) examinations within 7 d, 15 d, 1 month, 3 months and 6 months after symptom onset. The lesion volumes and relative ADC (rADC) values were measured in different stages of brainstem infarction. At the same time, motor deficits were assessed with Fugl⁃Meyer Motor Scale (FMMS) score. The difference of infarction volumes, rADC values and FMMS scores at different time points were compared. The correlation between infarction volumes, rADC values and FMMS scores was analysed, respectively. Results The infarction volumes significantly decreased progressively with time (F = 4.553, P = 0.003), while the rADC values significantly increased progressively with time (F = 22.991, P = 0.000). Negative correlation was seen between the lesion volume and FMMS score (r = ⁃ 0.686, P = 0.020) within 7 d, but no correlation was seen at other time points (P > 0.05). There was no significant correlation between rADC values and the FMMS scores after infarction (P > 0.05). Conclusion There is certain regularity in the changes of infarction volume and rADC value in patients with brainstem infarction in different stages. However, no strong correlation of early infarction size and rADC value with motor outcome is detected. DOI：10.3969/j.issn.1672-6731.2011.03.010

The use of MRI apparent diffusion coefficient (ADC) in monitoring the development of brain infarction

BackgroundTo study the rules that apparent diffusion coefficient (ADC) changes with time and space in cerebral infarction, and to provide the evidence in defining the infarction stages.Methods117 work-ups in 98 patients with cerebral infarction (12 hyperacute, 43 acute, 29 subacute, 10 steady, and 23 chronic infarctions) were imaged with both conventional MRI and diffusion weighted imaging. The average ADC values, the relative ADC (rADC) values, and the ADC values or rADC values from the center to the periphery of the lesion were calculated.ResultsThe average ADC values and the rADC values of hyperacute and acute infarction lesion depressed obviously. rADC values in hyperacute and acute stage was minimized, and increased progressively as time passed and appeared as "pseudonormal" values in approximately 8 to 14 days. Thereafter, rADC values became greater than normal in chronic stage. There was positive correlation between rADC values and time (P < 0.01). The ADC values and the rADC values in hyperacute and acute lesions had gradient signs that these lesions increased from the center to the periphery. The ADC values and the rADC values in subacute lesions had adverse gradient signs that these lesions decreased from the center to the periphery.ConclusionThe ADC values of infarction lesions have evolution rules with time and space. The evolution rules with time and those in space can be helpful to decide the clinical stage, and to provide the evidence in guiding the treatment or judging the prognosis in infarction.

MR exponential image in ischemic stroke: A preliminary evaluation

Background and purposeMagnetic resonance (MR) diffusion images, including both the diffusion-weighted image (DWI) and the apparent diffusion coefficient (ADC), allow detection of cerebral ischemic lesions within minutes of onset, and the contrast within the image is based on microscopic motion of the water. A third type of diffusion image can be created, “the exponential image”. Our goals were to evaluate the ability of exponential image in reflecting the changes in both DWI and ADC and whether it can replace these two sets of images in cerebral infarction patients. Patients and methodsA total of 51 patients were enrolled in the study, 47 were included in the analysis, and four were excluded from the study. Conventional and DW MRI were performed in 47 patients. For each patient DWI, ADC maps, and exponential images were reviewed and the change in signal intensity of the lesion compared with the contralateral normal side was measured (rSI) as well as the changes in (rADC). ResultsThere was a significant change in the rSIDW and rSIExp in late subacute and chronic stages (p<.001), however, rADC showed a significant decrease (p<.001) in hyperacute and acute stages, followed by a significant increase (p<.001) in the late subacute and chronic stages. rSIExp was highly correlated with the change in the rADC values in different stages of infarction (r=.72, p<.001). However, the changes in the rSIDW correlated less closely with the change in the rADC values (r=.35, (p<.05)). ConclusionExponential image offers a simple, more accurate replacement for both sets (DWI and ADC), by combining the advantages of both sets.

Diagnostic value of ADC and rADC of diffusion weighted imaging in malignant breast lesions

The aim of this study was to evaluate the value of diffusion weighted imaging (DWI) in the diagnosis of patients with breast diseases. Fifty-three consecutive patients were scanned with GE signa HDx 1.5 T magnetic resonance system equipped with 8-channel breast coil. DWI was scanned by SE-EPI sequence in b values of 500 s/mm(2) and 800 s/mm(2), respectively. The apparent diffusion coefficients (ADC) of these lesions were measured. The mean apparent diffusion coefficients (ADC) of these lesions were calculated in b values of 500 s/mm(2) and 800 s/mm(2), respectively. These lesions' ADC value (rADC) was counted respectively and the result of the rADC was equal to the lesion's ADC divided by the ADC of the ipsilateral normal breast tissue. Threshold of ADC and rADC for differential diagnosis was acquired by ROC (receiver operating characteristic curve) analysis. Different imaging technologies were evaluated emphasizing their sensitivity, specificity and accuracy. Sixty-six lesions of 53 cases were confirmed by pathology, including 39 malignant lesions and 27 benign lesions. (1) b = 500 s/mm(2), the threshold of ADC value was 1.435 x 10(-3) mm(2)/s, with a sensitivity of 82.1% and a specificity of 81.5%. The threshold of rADC value was 0.62, with a sensitivity of 76.9% and a specificity of 100%. (2) b = 800 s/mm(2), the threshold of ADC value was 1.295 x 10(-3) mm(2)/s, with a sensitivity of 79.5% and a specificity of 81.5%. The threshold of rADC value was 0.71, with a sensitivity of 89.7% and specificity of 88.9%. (3) The area under the ROC curve was increased for the four diagnostic indicators (ADC(500), ADC(800), rADC(500), rADC(800)). DWI spends short time, and it doesn't need contrast material. ADC value and rADC value have a high sensitivity and specificity as a diagnostic indicator. DWI is helpful in improving the specificity of MR and may become one of valuable conventional procedures for breast tumor diagnosis.

Usefulness of Diffusion-Weighted MRI for Differentiation between Parkinson's Disease and Parkinson Variant of Multiple System Atrophy.

Background and Purpose:Several studies have reported that diffusion-weighted imaging (DWI) is able to help discriminate a Parkinson variant of multiple system atrophy (MSA-p) from Parkinson’s disease (PD) on the basis of the increased regional apparent diffusion coefficient (rADC). We analyzed the usefulness of DWI by using the rADC for differential diagnosis between MSA-p and PD and investigated the correlation between the rADC value and clinical features of MSA-p and PD.Methods:Twelve patients with PD and 10 with MSA-p were studied. The rADC value was determined in different brain regions, including the dorsal putamen (DP) and middle cerebellar peduncles (MCP).Results:The rADC values of the DP showed a greater increase in MSA-p patients than in PD patients (p=0.03). MSA-p patients also presented increased rADC values of the MCP compared with PD patients (p=0.0001). In particular, the sensitivity, specificity and positive predictive values of the MCP rADC were higher than those of the DP rADC. However, DP and MCP rADC values were not correlated with clinical features in either MSA or PD patients.Conclusions:DWI discriminated between PD and MSA-p based on rADC values in DP and MCP. The MCP rADC value, in particular, could better discriminate MSA-p from PD.

White matter tractography by diffusion tensor imaging in prognosis of acute lacunar infarctions

To evaluate diffusion tensor tractography (DTT) of white matter in prognosis of acute lacunar infarctions. Twenty-eight patients of pyramidal tract strokes at the acute phase (<3 days) with a marked motor defect were examined. Lesions were identified on diffusion weighted imaging and isotropic imaging of DTI, and infarctions and the tract were shown on the DTT images simultaneously. The anatomic location and pattern of the lesions were visualized on DTT, with regard of the corticospinal tract (CST), all patients were divided into three clinical subgroups: in Group 1 infarction lesions were close to CST, in Group 2 CST was partial involved, in Group 3 lesions centered in the pyramidal tract. Subsequently, they were compared with the National Institutes of Health Stroke Scale (NIHSS) scores at acute phase (<3 days), early chronic phase (8 approximately 14 days), and outcome(30 approximately 60 days). NIHSS scores of Group 1(12/28) were not different with those of Group 2 (11/28) at the acute phase (U=-1.430, P>0.05), and NIHSS scores in Group 2 were significantly lower than those of Group 3(5/28) (U= -2.676, P <0.01). In the outcome, NIHSS scores of Group 1 were significantly lower than those of Group 2 (U= -2.501, P<0.05), NIHSS scores of Group 2 were significantly lower than those of Group 3 (U= -2.948, P<0.01). Among these three groups,Group 1 all had good recovery, Group 2 also had good recovery but sometimes with some mild motor disfunction, and Group 3 always had marked defect and minor improvement. Both rADC value and rFA value were induced in the acute lacunar infarctions. DTT is helpful in prognestic valuation of acute lacunar infarction by providing visualized stereo localization of CST and infarction lesions.

Apparent diffusion coefficient of the superior cerebellar peduncle differentiates progressive supranuclear palsy from Parkinson's disease

The early diagnosis of progressive supranuclear palsy (PSP) may be challenging, because of clinical overlapping features with Parkinson's disease (PD) and other parkinsonian syndromes such as the Parkinsonian variant of multiple system atrophy (MSA-P). Conventional MRI can help in differentiating parkinsonian disorders but its diagnostic accuracy is still unsatisfactory. On the basis of the pathological demonstration of superior cerebellar peduncle (SCP) atrophy in patients with PSP, we assessed the SCP apparent diffusion coefficient (ADC) values in patients with PSP, PD, and MSA-P in order to evaluate its differential diagnostic value in vivo. Twenty-eight patients with PSP (14 with possible-PSP and 14 with probable-PSP), 15 PD, 15 MSA-P, and 16 healthy subjects were studied by using diffusion weighted imaging (DWI). ADC was calculated in regions of interest defined in the left and right SCP by two clinically blinded operators. Intrarater (r = 0.98, P < 0.001) and interrater reliability (r = 0.97; P < 0.001) for SCP measurements were high. Patients with PSP had higher SCP rADC values (median 0.98 x 10(-3)mm(2)/s) than patients with PD (median 0.79 x 10(-3) mm(2)/s, P < 0.001), MSA-P (median 0.79 x 10(-3) mm(2)/s, P < 0.001), and healthy controls (median 0.80 x 10(-3) mm(2)/s, P < 0.001). DWI discriminated patients with PSP from PD and healthy subjects on the basis of SCP rADC individual values (100% sensitivity and specificity) and from patients with MSA-P (96.4% sensitivity and 93.3% specificity). The higher values of rADC in SCP of patients with PSP correspond with the in vivo microstructural feature of atrophy detected postmortem and provide an additional support for early discrimination between PSP and other neurodegenerative parkinsonisms.

MRI of the Perihemorrhagic Zone in a Rat ICH Model: Effect of Hematoma Evacuation

Perihemorrhagic pathophysiology of spontaneous intracerebral hemorrhages (ICH) remains unclear. Recently, ischemic changes in the perihemorrhagic zone (PHZ) have been discussed as a potential source of secondary damage. In this study, we focussed on diffusion and perfusion characteristics of experimental ICH. Experimental ICH was induced with a double injection model in rats. In total, 49 animals were examined at three timepoints within 3.5 h after ICH with a 2.35T animal scanner. We investigated perihemorrhagic relative apparent diffusion coefficients (rADC) and relative mean transit time (rMTT). Animals were divided into 2 groups; controls (gr1, n = 27) and facilitated hematoma evacuation with recombinant tissue plasminogen activator (rt-PA) after the first of 3 imaging time points (gr2, n = 22). Diffusion (rADC) and perfusion (rMTT) characteristics were analyzed in 3 regions of interest surrounding the hematoma (ROI1-3). Overall rADC and rMTT values in ROI3 (normal tissue) did not show any changes. There was mild edema--not ischemia--in ROIs1 and 2 at TP1 with rADC of 1.05-1.18 in both groups indicating vasogenic edema (not ischemia). This did not change with hematoma evacuation. There was mild (non-critical) perfusion reduction in ROIs1 and 2 at TP1, which disappeared after clot evacuation in group 2 (P < 0.05 for TP3). Multifactorial ANOVA showed a solid trend (0.06 < P < 0.1) for clot evacuation associated normalization of perfusion in ROIs 1 and 2 within and in between groups 1 and 2. We demonstrated vasogenic edema and mild perfusion reduction in the PHZ above the ischemic threshold. The existence of a perihemorrhagic "penumbra" indicating critically ischemic tissue analogous to ischemic stroke is unlikely.

Evolution of hippocampal CA‐1 diffusion lesions in transient global amnesia

Selective focal MR-Signal (diffusion-) changes in the CA-1 sector of the hippocampus have been described in transient global amnesia (TGA), but the pathophysiological substrate of these lesions is largely unknown. As several imaging and epidemiological findings point to a vascular origin an analysis of the temporal evolution of the hippocampal apparent diffusion coefficient (ADC) changes may offer new understanding of the pathomechanisms of TGA. The time course of the ADC of hippocampal DWI lesions in TGA patients was studied using serial 3 T high-resolution MR-imaging within 1-10 days as well as 4-6 months after TGA. ADC values from 76 MR-studies were analyzed and expressed as ratio ADC (rADC) in reference to the unaffected hemisphere. Twenty-nine patients with TGA showed 34 DWI lesions with corresponding T2 lesions in the CA-1 sector of the hippocampal cornu ammonis within a time window of 24-72 h after onset. Ratio ADC decreased below 1.0 (0.66 +/- 0.08) 24 h after the acute TGA episode and did show a further significant decrease to 0.57 +/- 0.1 after 3 days (p < 0.05). After 72 h, rADC increased and normalized around day 10 with rADC values of 1.0 (p < 0.05). The temporal evolution of the rADC in hippocampal signal changes in TGA shows a time course previously described for ischemic lesions in human stroke patients. This might imply a vascular origin of diffusion changes leading to a transient perturbation of memory relevant circuits in the hippocampus.

The effects of levodopa use on diffusion coefficients in various brain regions in Parkinson's disease

We aimed to evaluate the effects of l-dopa use on apparent diffusion coefficient (ADC) values of different brain regions in Parkinson's disease (PD) patients. Thirty-five subjects underwent magnetic resonance imaging (MRI), including 21 PD patients (13 men, 8 women; mean age, 63 years ± 8), and 14 sex and age-matched control subjects. PD patients were separated into two groups according to the duration of l-dopa usage: patients using l-dopa less and more than 1 year. According to the disease duration two other groups were formed: patients diagnosed less and more than 1 year. Unified Parkinson Disease Rating Scale (UPDRS) scores of PD patients were detected. Diffusion weighted images (DWI) and ADC maps of patients and controls were evaluated and regional ADC (rADC) measurements were performed. Patients’ age was not significantly different between groups. UPDRS was significantly different between the patient groups. There was no significant difference of rADC values between PD and control groups, and within the different PD groups. Short- and long-term l-dopa usage in PD patients did not cause any change rADC values in various brain regions.