Category Archives: Editor’s Choices

Repeatability of Standardized and Normalized Relative CBV in Patients with Newly Diagnosed Glioblastoma

Editor’s Choice

Editor’s Comment

Relative CBV estimates were calculated from dynamic susceptibility contrast MR imaging in double-baseline examinations of 33 patients with treatment-naïve and pathologically proved glioblastoma multiforme. Normalized and standardized relative CBV were calculated by using 6 common postprocessing methods. The ΔR2* estimation method that incorporates leakage correction offers the best repeatability for rCBV, with standardized rCBV being less variable.

Abstract

Visual comparison of nRCBV and sRCBV. Methods 1–6 (across) for visit 1 (top 2 rows) and visit 2 (bottom 2 rows) in the same subject in approximately the same section for visits 1 and 2. All data are presented with the same respective scale for nRCBV or sRCBV and are in arbitrary units.

Visual comparison of nRCBV and sRCBV. Methods 1–6 (across) for visit 1 (top 2 rows) and visit 2 (bottom 2 rows) in the same subject in approximately the same section for visits 1 and 2. All data are presented with the same respective scale for nRCBV or sRCBV and are in arbitrary units.

Background and Purpose

For more widespread clinical use advanced imaging methods such as relative cerebral blood volume must be both accurate and repeatable. The aim of this study was to determine the repeatability of relative CBV measurements in newly diagnosed glioblastoma multiforme by using several of the most commonly published estimation techniques.

Materials and Methods

The relative CBV estimates were calculated from dynamic susceptibility contrast MR imaging in double-baseline examinations for 33 patients with treatment-naïve and pathologically proved glioblastoma multiforme (men = 20; mean age = 55 years). Normalized and standardized relative CBV were calculated by using 6 common postprocessing methods. The repeatability of both normalized and standardized relative CBV, in both tumor and contralateral brain, was examined for each method with metrics of repeatability, including the repeatability coefficient and within-subject coefficient of variation. The minimum sample size required to detect a parameter change of 10% or 20% was also determined for both normalized relative CBV and standardized relative CBV for each estimation method.

Results

When ordered by the repeatability coefficient, methods using postprocessing leakage correction and ΔR2*(t) techniques offered superior repeatability. Across processing techniques, … Continue reading >>

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Aqueductal Stroke Volume: Comparisons with Intracranial Pressure Scores in Idiopathic Normal Pressure Hydrocephalus

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Editor’s Comment

Phase-contrast MR imaging was performed in 21 patients with probable idiopathic normal pressure hydrocephalus. Patients were selected for shunting on the basis of pathologically increased intracranial pressure pulsatility. Patients with shunts were offered a second MR imaging after 12 months. Ventricular volume and transverse aqueductal area were calculated. No correlations between aqueductal stroke volume and preoperative scores of mean intracranial pressure or mean wave amplitudes were observed. Aqueductal stroke volume does not reflect intracranial pressure pulsatility or symptom score, but rather aqueduct area and ventricular volume.

Abstract

ASV (A) and ventricular volume (B) are presented for patients with shunts and iNPH before (n = 17) and after (n = 12) shunting (surgery group) and for conservatively managed patients with iNPH (conservative group, n = 4) before management. Significance levels are presented in the plots.

ASV (A) and ventricular volume (B) are presented for patients with shunts and iNPH before (n = 17) and after (n = 12) shunting (surgery group) and for conservatively managed patients with iNPH (conservative group, n = 4) before management. Significance levels are presented in the plots.

Background and Purpose

Aqueductal stroke volume from phase-contrast MR imaging has been proposed for predicting shunt response in normal pressure hydrocephalus. However, this biomarker has remained controversial in use and has a lack of validation with invasive intracranial monitoring. We studied how aqueductal stroke volume compares with intracranial pressure scores in the presurgical work-up and clinical score, ventricular volume, and aqueduct area and assessed the patient’s response to shunting.

Materials and Methods

Phase-contrast MR imaging was performed in 21 patients with probable idiopathic normal pressure hydrocephalus. Patients were selected for shunting on the basis of pathologically increased intracranial pressure pulsatility. Patients with shunts were offered a second MR imaging after 12 months. Ventricular volume and transverse aqueductal area were calculated, as well as clinical symptom score.

Results

No correlations between aqueductal stroke volume and preoperative scores of mean intracranial pressure or mean wave amplitudes were observed. Preoperative aqueductal stroke volume was not different between patients with … Continue reading >>

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Temporal Bone CT: Improved Image Quality and Potential for Decreased Radiation Dose Using an Ultra-High-Resolution Scan Mode with an Iterative Reconstruction Algorithm

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Editor’s Comment

Patients with baseline temporal bone CT scans acquired by using a z-axis ultra-high-resolution protocol and a follow-up scan by using the ultra-high-resolution–iterative reconstruction technique were identified. Images of left and right temporal bones were reconstructed in the axial, coronal, and Poschl planes. Spatial resolution was comparable (Poschl) or slightly better (axial and coronal planes) with ultra-high-resolution–iterative reconstruction than with z-axis ultra-high-resolution. Paired t test indicated that noise was significantly lower with ultra-high-resolution–iterative reconstruction than with z-axis ultra-high-resolution.

Abstract

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Comparison of the spatial resolution of the incudomallear joint. Representative axial images of the incudomallear joint of the same patient scanned with the zUHR technique (A) and UHR-IR technique (B). The UHR-IR technique produced superior spatial resolution and lower image noise.

Background and Purpose

Radiation dose in temporal bone CT imaging can be high due to the requirement of high spatial resolution. In this study, we assessed whether CT imaging of the temporal bone by using an ultra-high-resolution scan mode combined with iterative reconstruction provides higher spatial resolution and lower image noise than a z-axis ultra-high-resolution mode.

Materials and Methods

Patients with baseline temporal bone CT scans acquired by using a z-axis ultra-high-resolution protocol and a follow-up scan by using the ultra-high-resolution–iterative reconstruction technique were identified. Images of left and right temporal bones were reconstructed in the axial, coronal, and Poschl planes. Three neuroradiologists assessed the spatial resolution of the following structures: round and oval windows, incudomallear and incudostapedial joints, basal turn spiral lamina, and scutum. The paired z-axis ultra-high-resolution and ultra-high-resolution–iterative reconstruction images were displayed side by side in random order, with readers blinded to the imaging protocol. Image noise was compared in ROIs over the posterior fossa.

Results

We identified 8 patients, yielding 16 sets of temporal bone images (left and right).

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Woven EndoBridge Intrasaccular Flow Disrupter for the Treatment of Ruptured and Unruptured Wide-Neck Cerebral Aneurysms: Report of 55 Cases

Editor’s Choice

Editor’s Comment

This is a retrospective study of all ruptured and unruptured aneurysms that were treated with a WEB device (WEB Dual-Layer, Single-Layer, and Single-Layer Sphere) between April 2012 and August 2014 at 2 centers. Fifty-five aneurysms in 52 patients, including 14 ruptured aneurysms, underwent treatment with the WEB device. A favorable angiographic result at 3 months was achieved in 66% of cases, whereas the percentage of good anatomic results increased from 40% in 2012 to 75% in 2014.

Abstract

Unruptured MCA aneurysm of the right side, treated with a WEB-DL 9 × 6 mm. A, Initial angiogram of the aneurysm. B, Unsubtracted image after deployment of the WEB-DL 9 × 6 mm. C, Initial result after implantation of the WEB. D, Angiographic follow-up after 10 months, confirming stable occlusion of the aneurysm.

Unruptured MCA aneurysm of the right side, treated with a WEB-DL 9 × 6 mm. A, Initial angiogram of the aneurysm. B, Unsubtracted image after deployment of the WEB-DL 9 × 6 mm. C, Initial result after implantation of the WEB. D, Angiographic follow-up after 10 months, confirming stable occlusion of the aneurysm.

Background and Purpose

The safety and efficacy of the Woven EndoBridge (WEB) device for the treatment of cerebral aneurysms have been investigated in several studies. Most of these studies focused on specific aneurysms or a certain WEB device. Our objective was to report the experience of 2 German centers with the WEB device, including technical feasibility, safety, and short-term angiographic outcome.

Materials and Methods

We performed a retrospective study of all ruptured and unruptured aneurysms that were treated with a WEB device (WEB Double-Layer, Single-Layer, and Single-Layer Sphere) between April 2012 and August 2014. Primary outcome measures included the feasibility of the implantation and the angiographic outcome at 3-month follow-up. Secondary outcome measures included the clinical outcome at discharge and procedural complications.

Results

Fifty-five aneurysms in 52 patients, including 14 ruptured aneurysms, underwent treatment with the WEB device. The median age of patients was 55 years (range, 30–75 years); 19/55 (37%) were men. The device could be deployed in all patients

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Improving Multiple Sclerosis Plaque Detection Using a Semiautomated Assistive Approach

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Editor’s Comment

The authors evaluated and validated a semiautomated software platform to facilitate detection of new lesions and improved MS lesions. Two neuroradiologists retrospectively assessed 161 MR imaging comparison study pairs acquired between 2009 and 2011. More comparison study pairs with new lesions and improved lesions were recorded by using the software compared with original radiology reports.

Abstract

Annotated capture of the software reporting screen. A, Axial FLAIR with superimposed change map shows the new occipital white matter lesion in orange. Coregistered and resectioned FLAIR sequences comparing axial of new study (B) with axial of old study (C); and sagittal of new study (E) with sagittal old study (F)—thus confirming that the lesion is real and consistent with a new demyelinating plaque. D, Each lesion is marked with 3D coordinates.

Annotated capture of the software reporting screen. A, Axial FLAIR with superimposed change map shows the new occipital white matter lesion in orange. Coregistered and resectioned FLAIR sequences comparing axial of new study (B) with axial of old study (C); and sagittal of new study (E) with sagittal old study (F)—thus confirming that the lesion is real and consistent with a new demyelinating plaque. D, Each lesion is marked with 3D coordinates.

Background and Purpose

Treating MS with disease-modifying drugs relies on accurate MR imaging follow-up to determine the treatment effect. We aimed to develop and validate a semiautomated software platform to facilitate detection of new lesions and improved lesions.

Materials and Methods

We developed VisTarsier to assist manual comparison of volumetric FLAIR sequences by using interstudy registration, resectioning, and color-map overlays that highlight new lesions and improved lesions. Using the software, 2 neuroradiologists retrospectively assessed MR imaging MS comparison study pairs acquired between 2009 and 2011 (161 comparison study pairs met the study inclusion criteria). Lesion detection and reading times were recorded. We tested inter- and intraobserver agreement and comparison with original clinical reports. Feedback was obtained from referring neurologists to assess the potential clinical impact.

Results

More comparison study pairs with new lesions (reader 1, n = 60; reader 2, n= 62) and improved lesions (reader 1, n = 28; reader 2, n = 39) were recorded

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Hyperintense Vessels on FLAIR: Hemodynamic Correlates and Response to Thrombolysis

Editor’s Choice

Editor’s Comment

The authors evaluated 62 consecutive patients with ischemic stroke with proven vessel occlusion with MRI before and within 24 hours of treatment and defined a hypoperfusion intensity ratio (volume with severe/mild hypoperfusion [time-to-maximum ≥ 8 seconds / time-to-maximum ≥ 2 seconds]). Patients with extensive hyperintense vessels on FLAIR (>4 sections) had higher NIHSS scores, larger baseline lesion volumes, higher rates of perfusion-diffusion mismatch, and more severe hypoperfusion intensity ratio.

Abstract

MR imaging (left-to-right: acute FLAIR, acute DWI, acute Tmax, dichotomized Tmax, follow-up DWI) of patients with middle cerebral artery occlusions (M1). Patient A (82 years of age; baseline NIHSS score, 13; baseline lesion volume, 1.4 mL; HIR, 0.031; recanalization to Thrombolysis in Myocardial Infarction 2 following treatment; absolute infarct growth, 3.3 mL) had FLAIR hyperintense vessels on 3 sections (FHV ≤ 4; not visible on the depicted section) and patient B (76 years of age; baseline NIHSS score, 23; baseline lesion volume, 63.8 mL; HIR, 0.53; no recanalization following treatment [Thrombolysis in Myocardial Infarction, 0]; absolute infarct growth, 80.2 mL) had FHV on 8 sections (arrows; FHV > 4).

MR imaging (left-to-right: acute FLAIR, acute DWI, acute Tmax, dichotomized Tmax, follow-up DWI) of patients with middle cerebral artery occlusions (M1). Patient A (82 years of age; baseline NIHSS score, 13; baseline lesion volume, 1.4 mL; HIR, 0.031; recanalization to Thrombolysis in Myocardial Infarction 2 following treatment; absolute infarct growth, 3.3 mL) had FLAIR hyperintense vessels on 3 sections (FHV ≤ 4; not visible on the depicted section) and patient B (76 years of age; baseline NIHSS score, 23; baseline lesion volume, 63.8 mL; HIR, 0.53; no recanalization following treatment [Thrombolysis in Myocardial Infarction, 0]; absolute infarct growth, 80.2 mL) had FHV on 8 sections (arrows; FHV > 4).

Background and Purpose

Hyperintense vessels on baseline FLAIR MR imaging of patients with ischemic stroke have been linked to leptomeningeal collateralization, yet the ability of these to maintain viable ischemic tissue remains unclear. We investigated whether hyperintense vessels on FLAIR are associated with the severity of hypoperfusion and response to thrombolysis in patients treated with intravenous tissue-plasminogen activator.

Materials and Methods

Consecutive patients with ischemic stroke with an MR imaging before and within 24 hours of treatment, with proved vessel occlusion and available time-to-maximum maps were included (n = 62). The severity of hypoperfusion was characterized on the basis of the hypoperfusion intensity ratio (volume with severe/mild hypoperfusion [time-to-maximum ≥ 8 seconds / time-to-maximum ≥ 2

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Disrupted Global and Regional Structural Networks and Subnetworks in Children with Localization-Related Epilepsy

Editor’s Choice

Editor’s Comment

Impaired structural connectivity affecting global and regional networks and subnetworks in children with localization-related epilepsy was demonstrated. The impairment in structural connectivity was extensive despite the apparent focality of the seizure disorders.

Abstract

Reduced nodal efficiency in localization-related epilepsy (A), frontal lobe epilepsy (B), and temporal lobe epilepsy (C) in patients relative to controls. The disrupted nodes with reduced nodal efficiency are shown in red, and the unaffected nodes are shown in blue. The size of the nodes is related to the significance of between-group differences in nodal efficiency, with larger nodes representing more significant (lower P value) reduced nodal efficiency in patients relative to controls.

Reduced nodal efficiency in localization-related epilepsy (A), frontal lobe epilepsy (B), and temporal lobe epilepsy (C) in patients relative to controls. The disrupted nodes with reduced nodal efficiency are shown in red, and the unaffected nodes are shown in blue. The size of the nodes is related to the significance of between-group differences in nodal efficiency, with larger nodes representing more significant (lower P value) reduced nodal efficiency in patients relative to controls.

Background and Purpose

Structural connectivity has been thought to be a less sensitive measure of network changes relative to functional connectivity in children with localization-related epilepsy. The aims of this study were to investigate the structural networks in children with localization-related epilepsy and to assess the relation among structural connectivity, intelligence quotient, and clinical parameters.

Materials and Methods

Forty-five children with nonlesional localization-related epilepsy and 28 healthy controls underwent DTI. Global network (network strength, clustering coefficient, characteristic path length, global efficiency, and small-world parameters), regional network (nodal efficiency), and the network-based statistic were compared between patients and controls and correlated with intelligence quotient and clinical parameters.

Results

Patients showed disrupted global network connectivity relative to controls, including reduced network strength, increased characteristic path length and reduced global efficiency, and reduced nodal efficiency in the frontal, temporal, and occipital lobes. Connectivity in multiple subnetworks was reduced in patients, including the frontal-temporal, insula-temporal, temporal-temporal, frontal-occipital, and temporal-occipital lobes. The frontal lobe epilepsy subgroup demonstrated more areas with reduced nodal efficiency and more impaired subnetworks than the temporal lobe epilepsy subgroup. Network parameters were not significantly associated with intelligence quotient, age at seizure

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Deconstructive and Reconstructive Techniques in Treatment of Vertebrobasilar Dissecting Aneurysms: A Systematic Review and Meta-Analysis

Editor’s Choice

Editor’s Comment

Seventeen studies with 478 patients were included in this analysis, evaluating immediate occlusion, long-term occlusion, long-term good neurologic outcome, perioperative morbidity, perioperative mortality, rebleed (ruptured only), recurrence, and retreatment. Endovascular treatment of vertebrobasilar dissecting aneurysms showed high rates of complete occlusion and good long-term outcomes.

Abstract

sonmez-tableBackground and Purpose

Various endovascular techniques have been applied to the treatment of vertebrobasilar dissecting aneurysms, including parent artery preservation with coiling, stent placement or flow diverter placement, and trapping and proximal occlusion. We performed a systematic review and meta-analysis to study clinical and angiographic outcomes of patients undergoing endovascular treatment of vertebrobasilar dissecting aneurysms.

Materials and Methods

We performed a comprehensive literature search for studies on the endovascular treatment of vertebrobasilar dissecting aneurysms. From each study we abstracted the following data: immediate occlusion, long-term occlusion, long-term good neurologic outcome, perioperative morbidity, perioperative mortality, rebleed (ruptured only), recurrence, and retreatment. We performed subgroup analyses of patients undergoing deconstructive-versus-reconstructive techniques. Meta-analysis was performed by using a random effects model.

Results

Seventeen studies with 478 patients were included in this analysis. Sixteen studies had at least 6 months of clinical/angiographic follow-up. Endovascular treatment was associated with high rates of long-term occlusion (87.0%; 95% CI, 74.0%–94.0%) and low recurrence (7.0%; 95% CI, 5.0%–10.0%) and retreatment rates (3.0%; 95% CI, 2.0%–6.0%). Long-term good neurologic outcome was 84.0% (95% CI, 65.0%–94.0%). Deconstructive techniques were associated with higher rates of long-term complete occlusion compared with reconstructive techniques (88.0%; 95% CI, 35.0%–99.0% versus 81.0%; 95% CI, 64.0%–91.0%; P < .0001). Deconstructive and reconstructive techniques were both associated with high rates of good neurologic outcome (86.0%; 95% CI, 68.0%–95.0% versus 92.0%; 95% CI, 86.0%–95.0%; P = .10).

Conclusions

Endovascular treatment of vertebrobasilar dissecting aneurysms is associated with high rates of complete occlusion and good long-term neurologic outcomes. Deconstructive

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Arterial Spin-Labeling Parameters Influence Signal Variability and Estimated Regional Relative Cerebral Blood Flow in Normal Aging and Mild Cognitive Impairment: FAIR versus PICORE Techniques

Editor’s Choice

Editor’s Comments

In healthy controls and 43 patients with mild cognitive impairment, 2 pulsed ASL sequences were performed at 3T: proximal inversion with a control for off-resonance effects (PICORE) and the flow-sensitive alternating inversion recovery technique (FAIR). FAIR had higher estimated relative CBF and lower interindividual variability than PICORE.

Abstract

The average rCBF for FAIR, PICORE, and the difference between both ASL sequences.

BACKGROUND AND PURPOSE

Arterial spin-labeling is a noninvasive method to map cerebral blood flow, which might be useful for early diagnosis of neurodegenerative diseases. We directly compared 2 arterial spin-labeling techniques in healthy elderly controls and individuals with mild cognitive impairment.

MATERIALS AND METHODS

This prospective study was approved by the local ethics committee and included 198 consecutive healthy controls (mean age, 73.65 ± 4.02 years) and 43 subjects with mild cognitive impairment (mean age, 73.38 ± 5.85 years). Two pulsed arterial spin-labeling sequences were performed at 3T: proximal inversion with a control for off-resonance effects (PICORE) and flow-sensitive alternating inversion recovery technique (FAIR). Relative cerebral blood flow maps were calculated by using commercial software and standard parameters. Data analysis included spatial normalization of gray matter–corrected relative CBF maps, whole-brain average, and voxelwise comparison of both arterial spin-labeling sequences.

RESULTS

Overall, FAIR yielded higher relative CBF values compared with PICORE (controls, 32.7 ± 7.1 versus 30.0 ± 13.1 mL/min/100 g, P = .05; mild cognitive impairment, 29.8 ± 5.4 versus 26.2 ± 8.6 mL/min/100 g, P < .05; all, 32.2 ± 6.8 versus 29.3 ± 12.3 mL/min/100 g, P < .05). FAIR had lower variability (controls, 36.2% versus 68.8%, P < .00001; mild cognitive impairment, 18.9% versus 22.9%, P < .0001; all, 34.4% versus 64.9% P < .00001). The detailed voxelwise analysis revealed a higher signal for FAIR, notably in both convexities, while PICORE had … Continue reading >>

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Editor’s Choices from June 2015

Hart BL, Ketai L. Armies of Pestilence: CNS Infections as Potential Weapons of Mass Destruction. http://www.ajnr.org/content/36/6/1018.full

The imaging findings of CNS infection agents that may be used by governments and terrorist groups are presented. Viruses and anthrax are highly infectious and effective biowarfare weapons but bacteria also fulfill these requirements.

Asdaghi N, Coulter JI, Modi J, et al. Statin Therapy Does Not Affect the Radiographic and Clinical Profile of Patients with TIA and Minor Stroke. http://www.ajnr.org/content/36/6/1076.full

Imaging and clinical outcomes of high-risk patients with TIA and stroke who underwent acute statin treatment were assessed. These patients tended to be older, male, hypertensive, and have more atherosclerotic disease than those who did not receive statins. Early statin therapy was not associated with a reduction of DWI-positive lesions, infarct volume, or functional outcome at 3 months.

Shams S, Martola J, Cavallin L, et al. SWI or T2*: Which MRI Sequence to Use in the Detection of Cerebral Microbleeds? The Karolinska Imaging Dementia Study. http://www.ajnr.org/content/36/6/1089.full

The prevalence of cerebral microbleeds was evaluated in 246 patients using T2* and SWI. Microbleeds were detected in 21% by SWI vs. 17% by T2* imaging. SWI performed well with both thin and thick sections. Thus, SWI is better than T2* for this purpose and robust enough to permit comparison across studies.… Continue reading >>

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