Dose reduction in dynamic perfusion CT of the brain: effects of the scan frequency on measurements of cerebral blood flow, cerebral blood volume, and mean transit time

The influence of the frequency of computed tomography (CT) image acquistion on the diagnostic quality of dynamic perfusion CT (PCT) studies of the brain was investigated. Eight patients with clinically suspected acute ischemia of one hemisphere underwent PCT, performed on average 3.4 h after the onset of symptoms. Sixty consecutive images per slice were obtained with individual CT images obtained at a temporal resolution of two images per second. Eight additional data sets were reconstructed with temporal resolutions ranging from one image per second to one image per 5 s. Cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) measurements were performed in identical regions of interest. Two neuroradiologists evaluated the PCT images visually to identify areas of abnormal perfusion. Perfusion images created up to a temporal resolution of one image per 3 s were rated to be diagnostically equal to the original data. Even at one image per 4 s, all areas of infarction were identified. Quantitative differences of CBF, CBV and MTT measurements were ≤10% up to one image per 3 s. For PCT of the brain, temporal resolution can be reduced to one image per 3 s without significant compromise in image quality. This significantly reduces the radiation dose of the patient.

[1]  Jens Ricke,et al.  Dynamic perfusion CT: optimizing the temporal resolution for the calculation of perfusion CT parameters in stroke patients. , 2007, European journal of radiology.

[2]  M. Wiesmann,et al.  Parametric Perfusion Imaging With Contrast-Enhanced Ultrasound in Acute Ischemic Stroke , 2004, Stroke.

[3]  B. Holman,et al.  Council on Cardiovascular Radiology of the American Heart Association , 1981 .

[4]  G D Rubin,et al.  Improved uniformity of aortic enhancement with customized contrast medium injection protocols at CT angiography. , 2000, Radiology.

[5]  K Nambu,et al.  A method of regional cerebral blood perfusion measurement using dynamic CT with an iodinated contrast medium , 1996, Acta neurologica Scandinavica. Supplementum.

[6]  F R Verdun,et al.  Using 80 kVp versus 120 kVp in perfusion CT measurement of regional cerebral blood flow. , 2000, AJNR. American journal of neuroradiology.

[7]  M. Wiesmann,et al.  Dynamic CT perfusion imaging of acute stroke. , 2000, AJNR. American journal of neuroradiology.

[8]  M. Wintermark,et al.  Imaging of acute ischemic brain injury: the return of computed tomography , 2003, Current opinion in neurology.

[9]  W. Yuh,et al.  Guidelines and recommendations for perfusion imaging in cerebral ischemia: A scientific statement for healthcare professionals by the writing group on perfusion imaging, from the Council on Cardiovascular Radiology of the American Heart Association. , 2003, Stroke.

[10]  M. Wintermark,et al.  Dynamic perfusion CT: optimizing the temporal resolution and contrast volume for calculation of perfusion CT parameters in stroke patients. , 2004, AJNR. American journal of neuroradiology.

[11]  M. König,et al.  Brain perfusion CT in acute stroke: current status. , 2003, European journal of radiology.

[12]  Hiroshi Niimi,et al.  Radiation-induced temporary hair loss as a radiation damage only occurring in patients who had the combination of MDCT and DSA , 2004, European Radiology.

[13]  MartinWiesmann,et al.  Parametric Perfusion Imaging With Contrast-Enhanced Ultrasound in Acute Ischemic Stroke , 2004 .

[14]  M. Wiesmann,et al.  Zerebrale Perfusionsbildgebung mittels Mehrschichtspiral-CT , 2004, Klinische Neuroradiologie.

[15]  Jean-Philippe Thiran,et al.  Prognostic accuracy of cerebral blood flow measurement by perfusion computed tomography, at the time of emergency room admission, in acute stroke patients , 2002, Annals of neurology.