Dynamic CT in posterior fossa diseases using a deconvolution technique

The controversial points arising from dynamic CT scans after a bolus injection of an intravenous contrast material were corrected according to the deconvolution technique in order to calculate the ideal mean transit time (MTT) non-invasively. Applying this technique to dynamic CT scans of posterior fossa diseases, a matrix algorithm was used in order to obtain the transfer function from the known input/output function. To be exact, the time-density curve (T/D curve) from the basilar artery, expressed by the triangular matrix, was used as an input function, while the T/D curve of the paired ROIs on the known midpons and cerebellum were both replaced with the column matrix. This technique has the advantage of being simple to implement, but the transformation also includes a factor which may give rise to unrealistic oscillation. How to correct it will be the subject of future discussion. (author)