Tag Archives: CT techniques

Aunt Mickey (They Look the Same until You Undress Them). Carotid-Cavernous Fistula or Something Else?

A middle age woman presented with left progressive proptosis.  A contrast enhanced CT was done and showed enlargement of the left superior ophthalmic vein on the axial plane (see below).  A coronal image confirmed this abnormality and demonstrated that the extraocular muscles and retro-orbital fat had a normal appearance.

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Physical examination showed no chemosis, vision loss or cranial nerve palsies.  Because of this the patient was brought back for repeat contrast enhanced CT of the orbits with Valsalva maneuver.  This study showed mild additional enlargement of the already prominent left superior ophthalmic vein and also of the right sided one … Continue reading >>

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CT Head – What Slice Thickness Do You Use?

Until recently we have been scanning routine CT heads using a sequential technique with 5 mm slices through the posterior fossa and 10 mm slices of the supratentorial compartment. With a change of machines the protocols were revamped and we are now using sequential 5 mm thick slices all the way through.

One of my colleagues has complained about this change, stating that lesion conspicuity will be reduced by using thinner slices above the tent. I personally prefer the uniform and thinner slice thickness but cannot find anything in the literature to support either argument – there is lots about … Continue reading >>

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Validation and Standardization of Stroke Perfusion Methods

CTP and MRP acquisition hardware, protocols,  post processing, and interpretation vary widely between centers.  If we are to use these techniques for rational triage of acute stroke patients to appropriate treatment, validation and standardization is required.  I encourage all who perform such imaging to participate in the “STIR” effort, being corrdinated by Max Wintermark et al at UCSF.… Continue reading >>

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