Fellows’ Journal Club

Genetically Defined Oligodendroglioma Is Characterized by Indistinct Tumor Borders at MRI

Fellows’ Journal Club

The authors wanted to determine whether imaging characteristics previously associated with oligodendroglial tumors were still applicable given the 2016 WHO classification that made IDH mutation and 1p/19q codeletion the defining features of oligodendroglioma. They found that 92% of genetically defined oligodendrogliomas had noncircumscribed borders, compared with 45% of non-1p/19q codeleted tumors with at least partial histologic oligodendroglial morphology. Ninety-nine percent of oligodendrogliomas were heterogeneous on T1- and/or T2-weighted imaging.

MR Fingerprinting of Adult Brain Tumors: Initial Experience

Fellows’ Journal Club

MR fingerprinting is a technique in which pseudorandomized acquisition parameters are used to simultaneously quantify multiple tissue properties, including T1 and T2 relaxation times. The authors evaluated the ability of MR fingerprinting–derived T1 and T2 relaxometry to differentiate the 3 common types of intra-axial brain tumors (17 glioblastomas, 6 lower grade gliomas, and 8 metastases). Using these parameters, they explored the T1 and T2 properties of peritumoral white matter in various tumor types. Mean T2 values could differentiate solid tumor regions of lowergrade gliomas from metastases and the mean T1 of peritumoral white matter surrounding lowergrade gliomas differed from peritumoral white matter around glioblastomas.

Effects of MRI Protocol Parameters, Preload Injection Dose, Fractionation Strategies, and Leakage Correction Algorithms on the Fidelity of Dynamic-Susceptibility Contrast MRI Estimates of Relative Cerebral Blood Volume in Gliomas

Fellows’ Journal Club

The authors used DSC-MR imaging simulations to examine the influence of various acquisition parameters and leakage-correction strategies on the faithful estimation of CBV. Optimal strategies were determined by protocol with the lowest mean error. They conclude that the choice of image acquisition and preload dosing and/or fractionation has tremendous impact on the fidelity of CBV estimation. A variety of acquisition strategies can be used to obtain similar accuracy of CBV estimation, while the bidirectional leakage-correction algorithm aids in minimizing errors in CBV estimation under all scenarios.

Transverse Sinus Stenosis Is the Most Sensitive MR Imaging Correlate of Idiopathic Intracranial Hypertension

Fellows’ Journal Club

MR imaging and MRV images from 63 patients with idiopathic intracranial hypertension and 96 controls were reviewed by using 3 independent procedures. MRV images were graded for the presence and degree of stenosis of the transverse sinus. Postgadolinium coronal T1-weighted sequences were evaluated independent of MRV. The dimensions of the proximal and distal transverse sinus were measured. Transverse sinus stenosis was identified bilaterally on MRV in 94% of patients with IIH and in 3% of controls. On coronal T1 postgadolinium MR images, transverse sinus stenosis was identified in 83% of patients with IIH and 7% of controls. The authors conclude that transverse sinus stenosis is the most useful and sensitive imaging indicator of this disease state.

Ascending and Descending Thoracic Vertebral Arteries

Fellows’ Journal Club

The authors report the angiographic anatomy and clinical significance of 9 cases of descending and 2 cases of ascending thoracic vertebral arteries. Located within the upper costotransverse spaces, ascending and descending thoracic vertebral arteries may have important implications during spine interventional or surgical procedures. They frequently provide radiculomedullary or bronchial branches, so they can also be implicated in spinal cord ischemia, as a supply of vascular malformations, or be a source of hemoptysis.

Endovascular Stroke Treatment of Nonagenarians

Fellows’ Journal Club

The purpose of this study was the evaluation of procedural and outcome data of patients 90 years of age or older undergoing endovascular stroke treatment. The authors retrospectively analyzed prospectively collected data of 29 patients (mean age 91.9 years) in whom endovascular stroke treatment was performed between January 2011 and January 2016 (from a cohort of 615 patients). Successful recanalization (TICI % 2b) was achieved in 22 patients (75.9%). In 9 patients, an NIHSS improvement ≥ 10 points was noted between admission and discharge. After 3 months, 17.2% of the patients had an mRS of 0-2. Despite high mortality rates (∼45%) and moderate overall outcome, 17.2% of the patients achieved mRS 0-2 or prestroke mRS, and no serious procedure-related complications occurred.

Abstract

BACKGROUND AND PURPOSE

Although endovascular treatment has become a standard therapy in patients with acute stroke, the benefit for very old patients remains uncertain. The purpose of this study was the evaluation of procedural and outcome data of patients ≥90 years undergoing endovascular stroke treatment.

MATERIALS AND METHODS

We retrospectively analyzed prospectively collected data of patients ≥90 years in whom endovascular stroke treatment was performed between January 2011 and January 2016. Recanalization was assessed according to the TICI score. The clinical condition was evaluated on admission (NIHSS, prestroke mRS), at discharge (NIHSS), and after 3 months (mRS).

RESULTS

Twenty-nine patients met the inclusion criteria for this analysis. The median prestroke mRS was 2. Successful recanalization (TICI ≥ 2b) was achieved in 22 patients (75.9%). In 9 patients, an NIHSS improvement ≥ 10 points was noted between admission and discharge. After 3 months, 17.2% of the patients had an mRS of 0–2 or exhibited prestroke mRS, and 24.1% achieved mRS 0–3. Mortality rate was 44.8%. There was only 1 minor procedure-related complication (small SAH without clinical

Synthetic MRI in the Detection of Multiple Sclerosis Plaques

Fellows’ Journal Club

In this retrospective study, synthetic T2-weighted, FLAIR, double inversion recovery, and phase-sensitive inversion recovery images were produced in 12 patients with MS after quantification of T1 and T2 values and proton density. Double inversion recovery images were optimized for each patient by adjusting the TI. The number of visible plaques was determined by a radiologist for a set of these 4 types of synthetic MR images and a set of conventional T1-weighted inversion recovery, T2-weighted, and FLAIR images. Conventional 3D double inversion recovery and other available images were used as the criterion standard. Synthetic MR imaging enabled detection of more MS plaques than conventional MR imaging in a comparable acquisition time (approximately 7 minutes). The contrast for MS plaques on synthetic double inversion recovery images was better than on conventional double inversion recovery images.

Abstract

Figure 1 from paper
An example of DIR optimization. A DIR image with a second TI of 460 ms (A) (as determined according to the equations in the main text) shows better delineation of MS plaques than a DIR image with a second TI of 360 ms (B) or 560 ms (C).

BACKGROUND AND PURPOSE

Synthetic MR imaging enables the creation of various contrast-weighted images including double inversion recovery and phase-sensitive inversion recovery from a single MR imaging quantification scan. Here, we assessed whether synthetic MR imaging is suitable for detecting MS plaques.

MATERIALS AND METHODS

Quantitative and conventional MR imaging data on 12 patients with MS were retrospectively analyzed. Synthetic T2-weighted, FLAIR, double inversion recovery, and phase-sensitive inversion recovery images were produced after quantification of T1 and T2 values and proton density. Double inversion recovery images were optimized for each patient by adjusting the TI. The number of visible plaques was determined by a radiologist for a set of these 4 types of synthetic MR

White Matter Injury and General Movements in High-Risk Preterm Infants

Fellows’ Journal Club

Cerebral palsy has been predicted by analysis of spontaneous movements in the infant termed “General Movement Assessment.” The authors evaluated the utility of General Movement Assessment in predicting adverse cognitive, language, and motor outcomes in very preterm infants and attempted to identify brain imaging markers associated with both adverse outcomes and aberrant general movements in 47 preterm infants using MRI volumetric analysis and DTI. Nine infants had aberrant general movements and were more likely to have adverse neurodevelopmental outcomes, compared with infants with normal movements. In infants with aberrant movements, Tract-Based Spatial Statistics analysis identified significantly lower fractional anisotropy in widespread WM tracts. They conclude that aberrant general movements at 10–15 weeks’ postterm are associated with adverse neurodevelopmental outcomes and specific white matter microstructure abnormalities for cognitive, language, and motor delays.

Abstract

Figure 1 from paper
Differences in white matter at term-equivalent age between infants with normal and aberrant fidgety movements at 10–15 weeks. Mean FA skeleton, in green, is overlaid on the mean FA map. Superimposed are pseudocolored voxels having significantly greater anisotropy in infants with normal than in infants with aberrant fidgety movements. Color bar shows the range of P values represented by the pseudocolors. Significantly higher regions of FA can be observed in the splenium (ccs) and genu (ccg) of the corpus callosum, inferior (ilf) and superior longitudinal fasciculus (slf), fronto-occipital fasciculus (fof), anterior (alic) and posterior (plic) internal capsule, corona radiata (cr), cerebellar peduncles (cp), and fornix/stria terminalis (fx/st). Z represents the MR imaging axial section coordinates (zero is the center of the anterior commissure).

BACKGROUND AND PURPOSE

Very preterm infants (birth weight, <1500 g) are at increased risk of cognitive and motor impairment, including cerebral palsy. These adverse neurodevelopmental outcomes are associated with white matter abnormalities on MR imaging at term-equivalent age. Cerebral palsy has been

Endovascular Therapy of M2 Occlusion in IMS III: Role of M2 Segment Definition and Location on Clinical and Revascularization Outcomes

Fellows’ Journal Club

The authors reviewed the impact of revascularization on clinical outcomes in 83 patients with M2 occlusions in the Interventional Management of Stroke III trial according to specific M1–M2 segment anatomic features. AnmRS 0–2 outcome was associated with reperfusion for M2 trunk (n = 9) or M2 division (n = 42) occlusions, but not for M2 branch occlusions (n = 28). Of the 83 participants with M2 occlusion who underwent endovascular therapy, 41.0% achieved mRS 0–2 at 90 days, including 46.6% with modified TICI 2–3 reperfusion compared with 26.1% with modified TICI 0–1 reperfusion. They conclude that mRS 0–2 at 90 days was dependent on reperfusion for M2 trunk but not for M2 branch occlusions in IMS III.

Abstract

Figure 1 from paper
A, Right M1 trunk gives rise to the ATA with the posterior temporal branch filling on microcatheter injection. B, Lateral view baseline common carotid arteriogram confirms mid- and posterior temporal lobe cortical supply from the patent posterior temporal artery.

BACKGROUND AND PURPOSE

Uncertainty persists regarding the safety and efficacy of endovascular therapy of M2 occlusions following IV tPA. We reviewed the impact of revascularization on clinical outcomes in 83 patients with M2 occlusions in the Interventional Management of Stroke III trial according to specific M1-M2 segment anatomic features.

MATERIALS AND METHODS

Perfusion of any M2 branch distinguished M2-versus-M1 occlusion. Prespecified modified TICI and arterial occlusive lesion revascularization and clinical mRS 0–2 end points at 90 days for endovascular therapy–treated M2 occlusions were analyzed. Post hoc analyses of the relationship of outcomes to multiple baseline angiographic M2 and M1 subgroup characteristics were performed.

RESULTS

Of 83 participants with M2 occlusion who underwent endovascular therapy, 41.0% achieved mRS 0–2 at 90 days, including 46.6% with modified TICI 2–3 reperfusion compared with 26.1% with modified TICI 0–1 reperfusion (risk

Fellows’ Journal Club Recap: Quantitative MRI for automated CSF measurements in hydrocephalus evaluation

Please check out the accompanying podcast of this blog post (discussion of this article begins at 15:07)

Current evaluation of idiopathic normal pressure hydrocephalus (NPH) depends predominantly on clinical examination, although there are some imaging features, including enlarged lateral ventricles, bowing of the corpus callosum, and enlargement of the sylvian fissures out of proportion to the other cerebrospinal fluid (CSF) spaces. However, these imaging features are largely subjective, depending heavily on the opinion of the interpreting physician.

In this paper, the authors sought to improve evaluation of idiopathic normal pressure hydrocephalus by developing an automated method for calculating CSF volumes within the calvarium, including volume in the lateral ventricles, total intracranial CSF volume, and brain parenchymal fraction. They compared this to manual segmentation and measured volumes in patients being evaluated for NPH both before and after a large volume lumbar puncture.

The results demonstrate that the method was useful for measuring CSF volumes, with good correlation between the automatic method and manual segmentation. Furthermore, the ventricular volume decreased after the large volume lumbar puncture, with the difference most pronounced 30 minutes after the procedure and gradually returning towards baseline over a 24 hour period. The method was also useful for calculating brain parenchymal fraction, which cannot be easily calculated manually.

These findings are interesting for several reasons. First, it is valuable to know that the automated method is reliable when compared to manual measurements and can be used to see how much change there is in the CSF volumes of patients being evaluated for normal pressure hydrocephalus. It is a natural extension of this study to see what the clinical outcomes were for these patients, and potentially know if there was a difference in patient that were ultimately diagnosed with NPH. Ideally, these values could potentially predict which …