头颅损伤CT片阅读技巧Word下载.docx

1、 Blood Can Be Very Bad. Content and images below are taken from his lecture （with his permission）.This stands forB - bloodC - cisternsB - brainV - ventriclesB - bonesStep: 1 bloodLook for any evidence of bleeding throughout all slices of the head CT.Blood will appear bright white and is typically in

2、 the range of 50-100 Houndsfield units.Basic categories of blood in the brain are epidural, subdural, intraparenchymal/intracerebral, intraventricular, and subarachnoid.Epidural （lens shaped, does not cross suture lines）Subdural （crescent shaped, does cross suture lines）Intraparenchymal /intracerbra

3、l hemorrhage （high density bleeds most often in the basal ganglia area if due to HTN）Intraventricular hemorrhageSubarachnoid hemorrhage （due most often to aneurysms, CT sensitivity decreases sharply with time） 2 cisterns2 Key questions to answer regarding the 4 key cisterns （Circummesencephalic, Sup

4、rasellar, Quadrigeminal and Sylvian）- Is there blood?-Are the cisterns open?Circummesencephalic cisternSuprasellar cisternQuadrigeminal cisternSylvian cistern 3 brainExamine the brain forSymmetry - make sure sulci and gyri appear the same on both sides. （easiest when patient not rotated in the scann

5、er）Grey-white differentiation - the earliest sign of a CVA on CT scan is the loss of the grey-white interface on CT scan. Compare side to side.Shift - the falx should be in the midline with ventricles the same on both sides. Check for effacement of sulci （unilateral or bilateral）.Hyper/hypodenisty -

6、 blood, calcification and IV contrast are hyperdense （appear lighter） and air, fat and areas of tumor ischemia are hypodense （appear darker）. 4 ventriclesExamine for IIIrd, IVth and lateral ventricles for dilation or compression/shift.Pathologic processes cause dilation （hydrocephalus） or compressio

7、n/shift. Communicating vs. Non-communicating. Communicating hydrocephalus is first evident in dilation of the temporal horns （normally small, slit-like）. The lateral, IIIrd, and IVth ventricles need to be examined for effacement, shift, and blood. 5 boneBone has the highest density on CT scan （whitest in appearance.） Evaluate for fracture.