J Korean Soc Magn Reson Med.  2012 Aug;16(2):142-151. 10.13104/jksmrm.2012.16.2.142.

Pseudo Continuous Arterial Spin Labeling MR Imaging of Status Epilepticus

• Yi M
• Choi SH
• Jung KH
• Yoon TJ
• Kim JH
• Sohn CH
• Chang KH

• KMID: 2099848
• DOI: http://doi.org/10.13104/jksmrm.2012.16.2.142

Abstract

PURPOSE
The purpose of this study was to describe arterial spin labeling MR image findings of status epilepticus.
MATERIALS AND METHODS
A retrospective chart review within our institute revealed six patients who had been clinically diagnosed as status epilepticus and had also undergone MR imaging that included ASL in addition to routine sequences.
RESULTS
Six patients with status epilepticus were studied by conventional MR and arterial spin labeling imaging. All patients showed increased regional CBF correlating with EEG pathology. Notably, in two patients, conventional MRI and DWI showed no abnormal findings whereas pCASL demonstrated regional increased CBF in both patients.
CONCLUSION
Arterial spin labeling might offer additional diagnostic capabilities in the evaluation of patients with status epilepticus.

Keyword

Status epilepticus; Arterial spin labeling; Cerebral blood flow; Magnetic resonance imaging (MRI)

MeSH Terms

Electroencephalography
Humans
Retrospective Studies
Status Epilepticus

Figure

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  Fig. 1 a. The pre and post pulses provide background suppression necessary for better contrast. Saturation was performed with crusher gradients inferior to the labeling plane, allowing for the increase in sharpness of the bolus. The arterial spin labeling experiment then consists of acquiring a labeled and a non-labeled (control) image and subtracting them to obtain the flow image. A 3D fast spin echo (FSE) spiral sequence has been implemented to acquire the signal which has prepared by the labeling sequence. The slice loop is the inner most and is acquired in a centric fashion. b. Quantification is performed as the equation, where 1.4 s for blood at 1.5 T is assumed. The partial saturation of the 'PD' reference image is corrected for a T1 of 1.2 s typical of gray matter (44). While a more fully relaxed signal would be desirable, the saturation of the receiver and the bright signal on the slightly T2-weighted FSE makes this undesirable. The partition coefficient, λ, was set to the whole brain average, 0.9, and the efficiency, ε, is set to 0.80 × 0.75. This quantification assumes the label remains in blood and thus T1 of the tissue, and the delay in the arrival time to the tissue, need not be quantified.

• 

  Fig. 2 An example of the ROI placement. ROIs were drawn in the both normal brain cortical areas and pathologic regions exhibiting the greatest CBF, and the values were recorded. CBF was calculated by dividing the measured values in ROIs by ten.

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  Fig. 3 60-year-old man presenting with generalized tonic-clonic seizure (patient 2). a. A T2-weighted image shows tortuous vascular structure (shown as signal voids), which suggests the presence of an arteriovenous malformation in the left temporo-occipital lobe. Diffuse increased T2 signal intensity in the same area was noted. b. Left vertebral angiogram shows an arteriovenous malformation in the left temporo-occipital lobe. c. DWI results demonstrate high SI in the left frontoparietal lobe. d. decreased ADC values were also observed in the affected area. e. pCASL images demonstrate a marked increase in CBF in the left frontoparietal lobe.

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  Fig. 4 21-year-old woman presenting with depression and altered mentality (patient 3). a, b. A T2-weighted image (a) and fluid attenuated inversion recovery image (b) show no focal abnormal signal intensity. c. DWI fails to depict any signal change. d. ADC also demonstrates normal values. e. pCASL images show diffusely increased CBF in bilateral regions of the cortex, particularly in the biparietal and occipital lobes.

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