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Mirjam I. Geerlings

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5 papers

1 author row

YNICL Journal 2015 Journal Article

Cerebellar infarct patterns: The SMART-Medea study

Laurens J.L. De Cocker
Mirjam I. Geerlings
Nolan S. Hartkamp
Anne M. Grool
Willem P. Mali
Yolanda Van der Graaf
Raoul P. Kloppenborg
Jeroen Hendrikse

OBJECTIVE: Previous studies on cerebellar infarcts have been largely restricted to acute infarcts in patients with clinical symptoms, and cerebellar infarcts have been evaluated with the almost exclusive use of transversal MR images. We aimed to document the occurrence and 3D-imaging patterns of cerebellar infarcts presenting as an incidental finding on MRI. METHODS: We analysed the 1.5 Tesla MRI, including 3D T1-weighted datasets, of 636 patients (mean age 62 ± 9 years, 81% male) from the SMART-Medea study. Cerebellar infarct analyses included an assessment of size, cavitation and gliosis, of grey and white matter involvement, and of infarct topography. RESULTS: One or more cerebellar infarcts (mean 1.97; range 1-11) were detected in 70 out of 636 patients (11%), with a total amount of 138 infarcts identified, 135 of which showed evidence of cavitation. The average mean axial diameter was 7 mm (range 2-54 mm), and 131 infarcts (95%) were smaller than 20 mm. Hundred-thirty-four infarcts (97%) involved the cortex, of which 12 in combination with subcortical white matter. No infarcts were restricted to subcortical branches of white matter. Small cortical infarcts involved the apex of a deep (pattern 1) or shallow fissure (pattern 2), or occurred alongside one (pattern 3) or opposite sides (pattern 4) of a fissure. Most (87%) cerebellar infarcts were situated in the posterior lobe. CONCLUSIONS: Small cerebellar infarcts proved to be much more common than larger infarcts, and preferentially involved the cortex. Small cortical infarcts predominantly involved the posterior lobes, showed sparing of subcortical white matter and occurred in characteristic topographic patterns.

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YNIMG Journal 2015 Journal Article

Quantitative comparison of 21 protocols for labeling hippocampal subfields and parahippocampal subregions in in vivo MRI: Towards a harmonized segmentation protocol

Paul A. Yushkevich
Robert S.C. Amaral
Jean C. Augustinack
Andrew R. Bender
Jeffrey D. Bernstein
Marina Boccardi
Martina Bocchetta
Alison C. Burggren

Objective An increasing number of human in vivo magnetic resonance imaging (MRI) studies have focused on examining the structure and function of the subfields of the hippocampal formation (the dentate gyrus, CA fields 1−3, and the subiculum) and subregions of the parahippocampal gyrus (entorhinal, perirhinal, and parahippocampal cortices). The ability to interpret the results of such studies and to relate them to each other would be improved if a common standard existed for labeling hippocampal subfields and parahippocampal subregions. Currently, research groups label different subsets of structures and use different rules, landmarks, and cues to define their anatomical extents. This paper characterizes, both qualitatively and quantitatively, the variability in the existing manual segmentation protocols for labeling hippocampal and parahippocampal substructures in MRI, with the goal of guiding subsequent work on developing a harmonized substructure segmentation protocol. Method MRI scans of a single healthy adult human subject were acquired both at 3T and 7T. Representatives from 21 research groups applied their respective manual segmentation protocols to the MRI modalities of their choice. The resulting set of 21 segmentations was analyzed in a common anatomical space to quantify similarity and identify areas of agreement. Results The differences between the 21 protocols include the region within which segmentation is performed, the set of anatomical labels used, and the extents of specific anatomical labels. The greatest overall disagreement among the protocols is at the CA1/subiculum boundary, and disagreement across all structures is greatest in the anterior portion of the hippocampal formation relative to the body and tail. Conclusions The combined examination of the 21 protocols in the same dataset suggests possible strategies towards developing a harmonized subfield segmentation protocol and facilitates comparison between published studies.

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YNICL Journal 2013 Journal Article

Hippocampal T2 hyperintensities on 7 Tesla MRI

Susanne J. van Veluw
Laura E.M. Wisse
Hugo J. Kuijf
Wim G.M. Spliet
Jeroen Hendrikse
Peter R. Luijten
Mirjam I. Geerlings
Geert Jan Biessels

Hippocampal focal T2 hyperintensities (HT2Hs), also referred to as hippocampal sulcal cavities, are a common finding on Magnetic Resonance (MR) images. There is uncertainty about their etiology and clinical significance. In this study we aimed to describe these HT2Hs in more detail using high resolution 7 Tesla MR imaging, addressing 1) the MR signal characteristics of HT2Hs, 2) their occurrence frequency, 3) their location within the hippocampus, and 4) their relation with age. We also performed an explorative post-mortem study to examine the histology of HT2Hs. Fifty-eight persons without a history of invalidating neurological or psychiatric disease (mean age 64 ± 8 years; range 43-78 years), recruited through their general practitioners, were included in this study. They all underwent 7 Tesla MRI, including a T1, T2, and FLAIR image. MR signal characteristics of the HT2Hs were assessed on these images by two raters. Also, the location and number of the HT2Hs were assessed. In addition, four formalin-fixed brain slices from two subjects were scanned overnight. HT2Hs identified in these slices were subjected to histopathological analysis. HT2Hs were present in 97% of the subjects (median number per person 10; range 0-20). All HT2Hs detected on the T2 sequence were hypointense on T1 weighted images. Of all HT2Hs, 94% was hypointense and 6% hyperintense on FLAIR. FLAIR hypointense HT2Hs were all located in the vestigial sulcus of the hippocampus, FLAIR hyperintense HT2Hs in the hippocampal sulcus or the gray matter. Post-mortem MRI and histopathological analysis suggested that the hypointense HT2Hs on FLAIR were cavities filled with cerebrospinal fluid. A hyperintense HT2H on FLAIR proved to be a microinfarct upon microscopy. In conclusion, hippocampal T2Hs are extremely common and unrelated to age. They can be divided into two types (hypo- and hyperintense on FLAIR), probably with different etiology.

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YNIMG Journal 2012 Journal Article

Efficient detection of cerebral microbleeds on 7.0T MR images using the radial symmetry transform

Hugo J. Kuijf
Jeroen de Bresser
Mirjam I. Geerlings
Mandy M.A. Conijn
Max A. Viergever
Geert Jan Biessels
Koen L. Vincken

Cerebral microbleeds (CMBs) are commonly detected on MRI and have recently received an increased interest, because they are associated with vascular disease and dementia. Identification and rating of CMBs on MRI images may be facilitated by semi-automatic detection, particularly on high-resolution images acquired at high field strength. For these images, visual rating is time-consuming and has limited reproducibility. We present the radial symmetry transform (RST) as an efficient method for semi-automated CMB detection on 7. 0T MR images, with a high sensitivity and a low number of false positives that have to be censored manually. The RST was computed on both echoes of a dual-echo T2*-weighted gradient echo 7. 0T MR sequence in 18 participants from the Second Manifestations of ARTerial disease (SMART) study. Potential CMBs were identified by combining the output of the transform on both echoes. Each potential CMB identified through the RST was visually checked by two raters to identify probable CMBs. The scoring time needed to manually reject false positives was recorded. The sensitivity of 71. 2% is higher than that of individual human raters on 7. 0T scans and the required human rater time is reduced from 30 to 2minutes per scan on average. The RST outperforms published semi-automated methods in terms of either a higher sensitivity or less false positives, and requires much less human rater time.

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YNIMG Journal 2012 Journal Article

Microbleeds, lacunar infarcts, white matter lesions and cerebrovascular reactivity — A 7T study

Mandy M.A. Conijn
Johannes M. Hoogduin
Yolanda Van der Graaf
Jeroen Hendrikse
Peter R. Luijten
Mirjam I. Geerlings

The underlying pathology of lacunar infarcts, white matter lesions and also of microbleeds is poorly understood. We assessed whether the presence of lacunar infarcts, white matter lesions or microbleeds on MRI was associated with a decrease in cerebrovascular reactivity, and assessed whether this association was similar for lacunar infarcts, white matter lesions and microbleeds. BOLD-fMRI scan with breath-holding at 7T and anatomical scans at 1. 5T were available in 49 patients with atherosclerotic disease from the Second Manifestations of ARTerial disease (SMART) study. Microbleeds and lacunar infarcts were scored visually and volumetric assessment of white matter lesions was performed on the 1. 5T scan. The percentage of voxels with a significant signal change on breath-holding and the whole brain signal change were calculated as measures of cerebrovascular reactivity. The mean percentage of voxels with a significant signal change was 25. 1% (SD 6. 6) and the mean percentage whole brain signal change was 1. 20% (SD 0. 51). Age, gender, and diastolic blood pressure were significantly associated with cerebrovascular reactivity. Cerebrovascular reactivity was lower with increasing age, lower in females compared to males and lower with lower diastolic blood pressure. ANCOVA showed that patients with microbleeds (n=18) had a significantly lower whole brain signal change than patients without microbleeds, with a mean difference of −0. 36% (95% CI −0. 64 to 0. 07), independent of age, sex, systolic and diastolic blood pressure and non-lacunar infarcts. No significant associations were found for presence of lacunar infarcts or white matter lesion volume with whole brain signal change or percentage of voxels with a significant signal change. The results show that presence of microbleeds is associated with an impaired cerebrovascular reactivity in patients with atherosclerotic disease, whereas no significant association was found for the presence of lacunar infarcts or white matter lesions in our study.

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