ALL IN THE HEAD
Image 1 : Pneumoencephalogram 1968 demonstrating progressive ventricular dilatation . Image courtesy of Journal of Neurosurgery .
Image 2 : Normal Head CT 1975 . Image courtesy of Siemens Medical .
Image 4 : CT Perfusion Legend Left : Pink is small infarct core . Right : Green is larger Left MCA ischemic penumbra . Image courtesy of RapidAi .
Image 3 : Normal Head CT current Image . Image courtesy of Siemens Medical .
syndromes . Good quality CT scanners are now available at most hospitals and imaging centers .
Since 1971 , many generations of CT scanners have been unveiled as the technology has been improved . Single detector single slice CT has been replaced with multiple detector multi-slice scanners . ( Image 3 ) Slip ring technology has allowed helical scanning in which a volume of tissue is imaged during one pass . The volume of tissue can be reconstructed in sub-centimeter slices and reformatted in multiple planes , usually sagittal and coronal . The imaging can be displayed using different algorithms : bone and soft tissue . Coupled with modern computers , the post processing is almost instantaneous . Current CT scanners are equipped with automatic dose reduction to scan with the lowest possible radiation dose ( ALARA ) to obtain diagnostic images . Reducing radiation exposure while obtaining high quality CT images will always be at the forefront of new scanner development . Because of multi-slice configuration , many commercially available CT scanners can image the entire brain
in a single rotation . Coupled with safer contrast , power injectors and innovative software programs , CT angiography ( CTA ) and CT perfusion ( CTP ) studies can be performed at most hospitals . ( Image 4 ) Recent studies have shown that CTP may now be useful in selecting patients who may benefit from endovascular therapies , such as mechanical thrombectomy based on a threshold National Institutes of Health Stroke Scale ( NIHSS ), or “ stroke score ,” and specific time frame . 2
Ultrasound ( US ) remains a valuable neuro imaging tool . Neonatal brain US was developed in the late 1970s and early 1980s . It is readily available , without radiation , and easily performed bedside in the neonatal ICU . It is used to diagnose and follow periventricular leukomalacia and periventricular or germinal matrix hemorrhage . Duplex carotid US is a noninvasive modality to screen for and follow carotid stenosis and patency and flow direction in the vertebral arteries . It is especially useful for patients with contraindications to MRI and / or contrast media . Intra-operative US can be utilized
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