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Nolan S. Hartkamp

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3 papers

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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

Neuronal activation induced BOLD and CBF responses upon acetazolamide administration in patients with steno-occlusive artery disease

Jeroen C.W. Siero
Nolan S. Hartkamp
Manus J. Donahue
Anita A. Harteveld
Annette Compter
Esben T. Petersen
Jeroen Hendrikse

Blood-oxygenation-level-dependent (BOLD) MRI is widely used for inferring neuronal activation and is becoming increasingly popular for assessing cerebrovascular reactivity (CVR) when combined with a vasoactive stimulus. The BOLD signal contains changes in cerebral blood flow (CBF) and thus information regarding neurovascular coupling and CVR. The BOLD signal, however, is also modulated by changes in cerebral blood volume (CBV) and cerebral metabolic rate of oxygen (CMRO2), as well as changes in the physiological baseline state. Here, we measured BOLD and CBF responses upon neuronal (visual) activation, before and after a vasodilatory challenge (acetazolamide, ACZ) in patients with vertebrobasilar steno-occlusive disease. After ACZ, the neuronal activation induced BOLD response was reduced or even negative (3 out of 8 subjects), whereas the CBF response remained similar. We show that BOLD alone cannot correctly assess the neuronal activation and underlying neurovascular coupling. The generally assumed positive relationship between BOLD and CBF responses may be severely compromised under changes in the physiological baseline state. Accompanying CBF measurements contain crucial information, and simulations suggest an altered flow–metabolism coupling in these patients.

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YNIMG Journal 2013 Journal Article

In vivo visualization of the PICA perfusion territory with super-selective pseudo-continuous arterial spin labeling MRI

Nolan S. Hartkamp
Laurens J. De Cocker
Michael Helle
Matthias J.P. van Osch
L. Jaap Kappelle
Reinoud P.H. Bokkers
Jeroen Hendrikse

In this work a method is described to discern the perfusion territories in the cerebellum that are exclusively supplied by either or both vertebral arteries. In normal vascular anatomy the posterior inferior cerebellar artery (PICA) is supplied exclusively by its ipsilateral vertebral artery. The perfusion territories of the vertebral arteries were determined in 14 healthy subjects by means of a super-selective pseudo-continuous ASL sequence on a 3T MRI scanner. Data is presented to show the feasibility of determining the PICA perfusion territory. In 10 subjects it was possible to accurately determine both PICA perfusion territories. In two subjects it was possible to determine the perfusion territory of one PICA. Examples in which it was not possible to accurately determine the PICA territory are also given. Additionally, the high variability of the extent of the PICA territory is illustrated using a statistical map. The posterior surface of the cerebellum is entirely supplied by the PICA in six subjects. The most posterior part of the superior surface is supplied by the PICA in eight subjects, and the inferior half of the anterior surface in six subjects. The inferior part of the vermis is supplied by the PICA in all subjects. Two subjects were found with interhemispheric blood flow to both tonsils from one PICA without contribution from the contralateral PICA. With the method as presented, clinicians may in the future accurately classify cerebellar infarcts according to affected perfusion territories, which might be helpful in the decision whether a stenosis should be considered symptomatic.

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