Clinically Relevant Imaging Features for <i>MGMT</i> Promoter Methylation in Multiple Glioblastoma Studies: A Systematic Review and Meta-Analysis

Suh, C.H.,Kim, H.S.,Jung, S.C.,Choi, C.G.,Kim, S.J. American Society of Neuroradiology 2018 American journal of neuroradiology Vol.39 No.8

<P><B>BACKGROUND:</B></P><P><I>O6-methylguanine methyltransferase</I> (<I>MGMT</I>) promoter methylation status has been reported as a prognostic biomarker in clinical trials.</P><P><B>PURPOSE:</B></P><P>Our aim was to systematically evaluate imaging features of <I>MGMT</I> promoter methylated glioblastoma and to determine the diagnostic performance of MR imaging for prediction of <I>MGMT</I> promoter methylation in patients with newly diagnosed glioblastoma.</P><P><B>DATA SOURCES:</B></P><P>A computerized search of Ovid MEDLINE and EMBASE up to February 27, 2018, was conducted.</P><P><B>STUDY SELECTION:</B></P><P>We selected studies evaluating imaging features of <I>MGMT</I> promoter methylated glioblastoma and the diagnostic performance of MR imaging for prediction of <I>MGMT</I> promoter methylation.</P><P><B>DATA ANALYSIS:</B></P><P>Pooled estimates of sensitivity and specificity were calculated using a hierarchic logistic regression model. Meta-regression and sensitivity analysis were performed.</P><P><B>DATA SYNTHESIS:</B></P><P>Twenty-two articles including 2199 patients were included. <I>MGMT</I> promoter methylated glioblastoma is likely to show less edema, high ADC, and low perfusion. Ten articles including 753 patients were included in the meta-analysis. The summary sensitivity was 79% (95% CI, 72%–85%), and the summary specificity was 78% (95% CI, 71%–84%). In the meta-regression, <I>MGMT</I> promoter methylation and mean age were associated with heterogeneity. Sensitivity analysis excluding 1 study resolved the heterogeneity.</P><P><B>LIMITATIONS:</B></P><P>Included studies used a variety of different MR imaging techniques to predict <I>MGMT</I> promoter methylation.</P><P><B>CONCLUSIONS:</B></P><P><I>MGMT</I> promotor methylated glioblastoma is likely to show less aggressive imaging features than <I>MGMT</I> promotor unmethylated glioblastoma. Despite the variety of different MR imaging techniques used, MR imaging in patients with newly diagnosed glioblastoma was shown to have the potential to predict <I>MGMT</I> promoter methylation noninvasively.</P>

Independent Poor Prognostic Factors for True Progression after Radiation Therapy and Concomitant Temozolomide in Patients with Glioblastoma: Subependymal Enhancement and Low ADC Value

Yoo, R.-E.,Choi, S.H.,Kim, T.M.,Lee, S.-H.,Park, C.-K.,Park, S.-H.,Kim, I.H.,Yun, T.J.,Kim, J.-H.,Sohn, C.H. American Society of Neuroradiology 2015 American journal of neuroradiology Vol.36 No.10

<P><B>BACKGROUND AND PURPOSE:</B></P><P>Subependymal enhancement and DWI have been reported to be useful MR imaging markers for identifying true progression. Our aim was to determine whether the subependymal enhancement pattern and ADC can differentiate true progression from pseudoprogression in patients with glioblastoma multiforme treated with concurrent chemoradiotherapy by using temozolomide.</P><P><B>MATERIALS AND METHODS:</B></P><P>Forty-two patients with glioblastoma multiforme with newly developed or enlarged enhancing lesions on the first follow-up MR images obtained within 2 months of concurrent chemoradiotherapy completion were included. Subependymal enhancement was analyzed for the presence, location, and pattern (local or distant relative to enhancing lesions). The mean ADC value and the fifth percentile of the cumulative ADC histogram were determined. A multiple logistic regression analysis was performed to identify independent factors associated with true progression.</P><P><B>RESULTS:</B></P><P>Distant subependymal enhancement (ie, extending >1 cm or isolated from the enhancing lesion) was significantly more common in true progression (<I>n</I> = 24) than in pseudoprogression (<I>n</I> = 18) (<I>P</I> = .042). The fifth percentile of the cumulative ADC histogram was significantly lower in true progression than in pseudoprogression (<I>P</I> = .014). Both the distant subependymal enhancement and the fifth percentile of the cumulative ADC histogram were independent factors associated with true progression (<I>P</I> = .041 and <I>P</I> = .033, respectively). Sensitivity and specificity for the diagnosis of true progression were 83% and 67%, respectively, by using both factors.</P><P><B>CONCLUSIONS:</B></P><P>Both the distant subependymal enhancement and the fifth percentile of the cumulative ADC histogram were significant independent factors predictive of true progression.</P>

Differentiation between Cystic Pituitary Adenomas and Rathke Cleft Cysts: A Diagnostic Model Using MRI

Park, M.,Lee, S.-K.,Choi, J.,Kim, S.-H.,Kim, S.H.,Shin, N.-Y.,Kim, J.,Ahn, S.S. American Society of Neuroradiology 2015 American journal of neuroradiology Vol.36 No.10

<P>This is a retrospective study that included 54 patients with a cystic pituitary adenoma and 28 patients with a Rathke cleft cyst who underwent MR imaging followed by surgery. Regression analysis showed that cystic pituitary adenomas and Rathke cleft cysts could be distinguished on the basis of the presence of a fluid-fluid level, septation, an off-midline location, and the presence of an intracystic nodule.</P><P><B>BACKGROUND AND PURPOSE:</B></P><P>Cystic pituitary adenomas may mimic Rathke cleft cysts when there is no solid enhancing component found on MR imaging, and preoperative differentiation may enable a more appropriate selection of treatment strategies. We investigated the diagnostic potential of MR imaging features to differentiate cystic pituitary adenomas from Rathke cleft cysts and to develop a diagnostic model.</P><P><B>MATERIALS AND METHODS:</B></P><P>This retrospective study included 54 patients with a cystic pituitary adenoma (40 women; mean age, 37.7 years) and 28 with a Rathke cleft cyst (18 women; mean age, 31.5 years) who underwent MR imaging followed by surgery. The following imaging features were assessed: the presence or absence of a fluid-fluid level, a hypointense rim on T2-weighted images, septation, an off-midline location, the presence or absence of an intracystic nodule, size change, and signal change. On the basis of the results of logistic regression analysis, a diagnostic tree model was developed to differentiate between cystic pituitary adenomas and Rathke cleft cysts. External validation was performed for an additional 16 patients with a cystic pituitary adenoma and 8 patients with a Rathke cleft cyst.</P><P><B>RESULTS:</B></P><P>The presence of a fluid-fluid level, a hypointense rim on T2-weighted images, septation, and an off-midline location were more common with pituitary adenomas, whereas the presence of an intracystic nodule was more common with Rathke cleft cysts. Multiple logistic regression analysis showed that cystic pituitary adenomas and Rathke cleft cysts can be distinguished on the basis of the presence of a fluid-fluid level, septation, an off-midline location, and the presence of an intracystic nodule (<I>P</I> = .006, .032, .001, and .023, respectively). Among 24 patients in the external validation population, 22 were classified correctly on the basis of the diagnostic tree model used in this study.</P><P><B>CONCLUSIONS:</B></P><P>A systematic approach using this diagnostic tree model can be helpful in distinguishing cystic pituitary adenomas from Rathke cleft cysts.</P>

Effects of Agmatine on Blood-Brain Barrier Stabilization Assessed by Permeability MRI in a Rat Model of Transient Cerebral Ischemia

Ahn, S.S.,Kim, S.H.,Lee, J.E.,Ahn, K.J.,Kim, D.J.,Choi, H.S.,Kim, J.,Shin, N.-Y.,Lee, S.-K. American Society of Neuroradiology 2015 American journal of neuroradiology Vol.36 No.2

<P><B>BACKGROUND AND PURPOSE:</B></P><P>BBB disruption after acute ischemic stroke and subsequent permeability increase may be enhanced by reperfusion. Agmatine has been reported to attenuate BBB disruption. Our aim was to evaluate the effects of agmatine on BBB stabilization in a rat model of transient cerebral ischemia by using permeability dynamic contrast-enhanced MR imaging at early stages and subsequently to demonstrate the feasibility of dynamic contrast-enhanced MR imaging for the investigation of new therapies.</P><P><B>MATERIALS AND METHODS:</B></P><P>Thirty-four male Sprague-Dawley rats were subjected to transient MCA occlusion for 90 minutes. Immediately after reperfusion, agmatine (100 mg/kg) or normal saline was injected intraperitoneally into the agmatine-treated group (<I>n</I> = 17) or the control group, respectively. MR imaging was performed after reperfusion. For quantitative analysis, regions of interest were defined within the infarct area, and values for volume transfer constant, rate transfer coefficient, volume fraction of extravascular extracellular space, and volume fraction of blood plasma were obtained. Infarct volume, infarct growth, quantitative imaging parameters, and numbers of factor VIII–positive cells after immunohistochemical staining were compared between control and agmatine-treated groups.</P><P><B>RESULTS:</B></P><P>Among the permeability parameters, volume transfer constant and volume fraction of extravascular extracellular space were significantly lower in the agmatine-treated group compared with the control group (0.05 ± 0.02 minutes<SUP>−1</SUP> versus 0.08 ± 0.03 minute<SUP>−1</SUP>, <I>P</I> = .012, for volume transfer constant and 0.12 ± 0.06 versus 0.22 ± 0.15, <I>P</I> = .02 for volume fraction of extravascular extracellular space). Other permeability parameters were not significantly different between the groups. The number of factor VIII–positive cells was less in the agmatine-treated group than in the control group (3-fold versus 4-fold, <I>P</I> = .037).</P><P><B>CONCLUSIONS:</B></P><P>In ischemic stroke, agmatine protects the BBB, which can be monitored in vivo by quantification of permeability by using dynamic contrast-enhanced MR imaging. Therefore, dynamic contrast-enhanced MR imaging may serve as a potential imaging biomarker for assessing the BBB stabilization properties of pharmacologic agents.</P>

Nigrosome 1 Detection at 3T MRI for the Diagnosis of Early-Stage Idiopathic Parkinson Disease: Assessment of Diagnostic Accuracy and Agreement on Imaging Asymmetry and Clinical Laterality

Noh, Y.,Sung, Y.H.,Lee, J.,Kim, E.Y. American Society of Neuroradiology 2015 American journal of neuroradiology Vol.36 No.11

<P>Nigrosomes are calbindin-poor zones within the substantia nigra pars compacta, and are the primary subregion where dopaminergic cells are lost in Parkinson disease. High-resolution 3D multiecho imaging was performed at 3T in 13 healthy subjects and 24 patients with idiopathic Parkinson disease confirmed by <SUP>18</SUP>F-FP-CIT PET. Diagnostic sensitivity, specificity, and accuracy of the nigrosome 1 detection at 3T MR imaging was 100%, 84.6%, and 94.6%, respectively. Further, the clinical laterality was in high concordance with the laterality of the nigrosome 1 detection.</P><P><B>BACKGROUND AND PURPOSE:</B></P><P>In the early stages of idiopathic Parkinson disease, motor symptoms are usually asymmetric. We aimed to assess the feasibility of nigrosome 1 detection at 3T MR imaging to analyze the agreement of its asymmetry and clinical laterality.</P><P><B>MATERIALS AND METHODS:</B></P><P>High-resolution 3D multiecho imaging was performed at 3T MR imaging in 13 healthy subjects and 24 patients with idiopathic Parkinson disease confirmed by N-3-fluoropropyl-2-β-carbomethoxy-3-β-(4-iodophenyl) nortropane (<SUP>18</SUP>F-FP-CIT) PET. The nigrosome 1 detection findings by using the MR imaging data were rated as “normal,” “possibly abnormal,” and “abnormal” by 2 independent reviewers. The degree of <SUP>18</SUP>F-FP-CIT binding was visually assessed in the caudate nucleus and putamen on PET images. Clinical laterality was evaluated by scores of the Unified Parkinson Disease Rating Scale, Part III. Asymmetry of the affected nigrosome 1 and the degree of <SUP>18</SUP>F-FP-CIT binding were analyzed for agreement with clinical laterality.</P><P><B>RESULTS:</B></P><P>The diagnostic sensitivity, specificity, and accuracy of the nigrosome 1 detection at 3T MR imaging was 100%, 84.6%, and 94.6%, respectively. Interrater agreements for the abnormality and asymmetry of nigrosome 1 were excellent (κ = 0.863 and 0.835, respectively). In patients with idiopathic Parkinson disease, the agreement of asymmetry between clinical laterality and nigrosome 1 detection was good (κ = 0.724). The degree of the <SUP>18</SUP>F-FP-CIT PET binding showed fair agreement (κ = 0.235) with clinical laterality.</P><P><B>CONCLUSIONS:</B></P><P>The abnormality involving nigrosome 1 can be detected at 3T MR imaging with an accuracy of 94.6%. The clinical laterality is in high concordance with the laterality of the nigrosome 1 detection at 3T (κ = 0.724).</P>

Cerebral Microbleeds in Patients with Dementia with Lewy Bodies and Parkinson Disease Dementia

Kim, S.W.,Chung, S.J.,Oh, Y.-S.,Yoon, J.H.,Sunwoo, M.K.,Hong, J.Y.,Kim, J.-S.,Lee, P.H. American Society of Neuroradiology 2015 American journal of neuroradiology Vol.36 No.9

<P><B>BACKGROUND AND PURPOSE:</B></P><P>The burden of amyloid β is greater in patients with dementia with Lewy bodies than in those with Parkinson disease dementia, and an increased amyloid β load is closely related to a higher incidence of cerebral microbleeds. Here, we investigated the prevalence and topography of cerebral microbleeds in patients with dementia with Lewy bodies and those with Parkinson disease dementia to examine whether cerebral microbleeds are more prevalent in patients with dementia with Lewy bodies than in those with Parkinson disease dementia.</P><P><B>MATERIALS AND METHODS:</B></P><P>The study population consisted of 42 patients with dementia with Lewy bodies, 88 patients with Parkinson disease dementia, and 35 controls who underwent brain MR imaging with gradient recalled-echo. Cerebral microbleeds were classified as deep, lobar, or infratentorial.</P><P><B>RESULTS:</B></P><P>The frequency of cerebral microbleeds was significantly greater in patients with dementia with Lewy bodies (45.2%) than in those with Parkinson disease dementia (26.1%) or in healthy controls (17.1%; <I>P</I> = .017). Lobar cerebral microbleeds were observed more frequently in the dementia with Lewy bodies group (40.5%) than in the Parkinson disease dementia (17%; <I>P</I> = .004) or healthy control (8.6%; <I>P</I> = .001) group, whereas the frequencies of deep and infratentorial cerebral microbleeds did not differ among the 3 groups. Logistic regression analyses revealed that, compared with the healthy control group, the dementia with Lewy bodies group was significantly associated with the presence of lobar cerebral microbleeds after adjusting for age, sex, nonlobar cerebral microbleeds, white matter hyperintensities, and other vascular risk factors (odds ratio, 4.39 [95% CI, 1.27–15.25]). However, compared with the healthy control group, the Parkinson disease dementia group was not significantly associated with lobar cerebral microbleeds.</P><P><B>CONCLUSIONS:</B></P><P>This study showed that patients with dementia with Lewy bodies had a greater burden of cerebral microbleeds and exhibited a lobar predominance of cerebral microbleeds than did patients with Parkinson disease dementia.</P>

Probabilistic Somatotopy of the Spinothalamic Pathway at the Ventroposterolateral Nucleus of the Thalamus in the Human Brain

Hong, J.H.,Kwon, H.G.,Jang, S.H. American Society of Neuroradiology 2011 AJNR, American journal of neuroradiology Vol.32 No.7

Hippocampal Shape Deformation in Female Patients with Unremitting Major Depressive Disorder

Tae, W.S.,Kim, S.S.,Lee, K.U.,Nam, E.C.,Choi, J.W.,Park, J.I. American Society of Neuroradiology 2011 AJNR, American journal of neuroradiology Vol.32 No.4

The Characteristics and Risk Factors of Headache Development after the Coil Embolization of an Unruptured Aneurysm

Hwang, G.,Jeong, E.-A.,Sohn, J.H.,Park, H.,Bang, J.S.,Jin, S.-C.,Kim, B.C.,Oh, C.W.,Kwon, O.-K. American Society of Neuroradiology 2012 American journal of neuroradiology Vol.33 No.9

<P>Development of a headache after aneurysm coil embolization is not uncommon but has received little attention. The authors prospectively analyze the characteristics and risk factors of a headache after coiling in patients treated for an unruptured cerebral aneurysm.</P>

Acute Basilar Artery Occlusion: Outcome of Mechanical Thrombectomy with Solitaire Stent within 8 Hours of Stroke Onset

Baek, J.M.,Yoon, W.,Kim, S.K.,Jung, M.Y.,Park, M.S.,Kim, J.T.,Kang, H.K. American Society of Neuroradiology 2014 American journal of neuroradiology Vol.35 No.5

<P><B>BACKGROUND AND PURPOSE:</B></P><P>Mechanical thrombectomy with a stent retriever applied shortly after symptom onset could increase good functional outcomes and improve survival in patients with acute basilar artery occlusion, but this has not yet been studied. This study evaluated the efficacy and safety of mechanical thrombectomy with a Solitaire stent within 8 hours of stroke onset in patients with acute basilar artery occlusion.</P><P><B>MATERIALS AND METHODS:</B></P><P>We analyzed 25 consecutive patients with acute basilar artery occlusion who were treated with mechanical thrombectomy by use of the Solitaire stent within 8 hours of stroke symptom onset. Successful recanalization was defined as TICI grade 2b or 3. Good outcome was defined as mRS score of 0–2 at 3 months. Clinical and radiologic data in patients with good outcomes were compared with those with poor outcomes.</P><P><B>RESULTS:</B></P><P>Successful recanalization was achieved in 96% (24/25) of patients, and 48% (12/25) of patients had good outcomes. Eighty-eight percent (22/25) of patients survived to 3 months. The median NIHSS score on admission was significantly lower in patients with good outcomes than in those with poor outcomes (9.5 versus 14, <I>P</I> = .005). Procedure-related complications occurred in 2 patients (8%). No symptomatic intracerebral hemorrhages occurred.</P><P><B>CONCLUSIONS:</B></P><P>The current study suggests that mechanical thrombectomy by use of a Solitaire stent within 8 hours of stroke onset increases good outcomes and improves survival in patients with acute basilar artery occlusion.</P>