CT scans

FIGURE 2.11 Matched diffusion and perfusion abnormalities. An early DWI image (a) shows an acute infarct in the left thalamus. An MTT map (b) shows a small perfusion abnormality that is no larger than the diffusion abnormality. When diffusion and perfusion lesions are matched, there is usually minimal if any infarct extension. Indeed, in this case, a follow-up CT scan (c) shows no enlargement of the infarct. 

Noncontrast CT scan without hemorrhage or well-established infarct. 

TanedaM, HayakawaT, Mogami H. Primary cerebellar hemorrhage quadrigeminal cistern obliteration on CT scans as a predictor of outcome. J Neurosurg 1987 67(4) 545-552. Raco A, Caroli E, Isidori A, Salvati M. Management of acute cerebellar infarction one institution s experience. Neurosurgery 2003 53(5) 1061-1065. 

Since functional outcome and risk of recurrent stroke are, in part, predictable based on the pathophysiologic subtype of stroke, the ability to accurately classify patients based on emergency clinical and imaging data would provide valuable predictive information. Unfortunately, misclassifications of stroke subtypes based on clinical data and a noncontrast CT scan are common. The final subtyping of stroke is made with all available clinical data, but is heavily influenced by neuroimaging studies that identify the location, size, and vascular distribution of the infarct, or that establish that the arteries supplying the region of stroke are stenotic or occluded. 

TABLE 10.1 Inter-Rater Agreement Expressed as Kappa (k) Scores for 26 CT Scans Interpreted by a Stroke Nenrologist and a Staff Neuroradiologist. ... 

The porosity can be determined by knowing locally the amount of fluid that saturates the pore space. Conventionally, an average value of the porosity is determined gravimetrically. X-ray CT scanning [3] or MRI [4] can be used to determine spatial distributions of porosity - the latter method is demonstrated in this chapter. 

Evidence of intracranial hemorrhage, subarachnoid hemorrhage, or a large area of cerebral edema, parenchymal hypodensities, or sulcal effacement on pretreatment CT scan... 

V/Q scan and CT scans are the most commonly used tests to diagnose PE. A V/Q scan measures the distribution of blood and air flow in the lungs. When there is a large mismatch between blood and air flow in one area of the lung, there is a high probability that the patient has a PE. Spiral CT scans can detect emboli in the pulmonary arteries. 

A computed tomography (CT) scan of the head will reveal an area of hyperintensity (white) identifying that a hemorrhage has occurred. The CT scan will either be normal... 

Magnetic resonance imaging (MRI) of the head will reveal areas of ischemia earlier and with better resolution than a CT scan. Some types of imaging can reveal an evolving infarct within minutes. 

In the emergency department an IV line is placed, a physical and neurologic exam is completed, and GR is moved to the stroke unit. The CT scan is negative for hemorrhagic stroke. 

Perform a CT scan to rule out a hemorrhagic stroke prior to administering any treatment. 

The patient s history will identify risk factors for acute pancreatitis, such as age greater than 70 years or history of alcohol abuse. Finally, computed tomography (CT) scan or ultrasound of the abdomen can help to identify pancreatic fluid collections.12... 

The goals of treatment for acute pancreatitis include (1) resolution of nausea, vomiting, abdominal pain, and fever (2) ability to tolerate oral intake (3) normalization of serum amylase, lipase, and white blood cell count and (4) resolution of abscess, pseudocyst, or fluid collection as measured by CT scan. 

Amylase 100 units/L (1.67 pKat/L), lipase 100 units/L CT scan Diffuse pancreatic scarring and calcifications... 

It has been forty-five minutes since CH s arrival, and he has been given lorazepam 4 mg twice and loaded with 1500 mg of phenytoin. He received another 400 mg dose of phenytoin 15 minutes ago, but is still unarousable. His jerking movements have slowed down, but his temperature is now 39.9°C (103.8°F), and his blood pressure has dropped to 124/62 mm Hg. His oxygen saturation is 91% on 4 L oxygen via nasal cannula. Bilateral crackles are heard upon auscultation of his lungs. A CT scan of his head is obtained which shows no evidence of hemorrhage, tumor, or mass effect. 

Review laboratory results and correct any underlying abnormalities CT scan (if seizures controlled)... 

VS blood pressure 128/62 mm Hg supine, pulse 77 beats per minute, respiratory rate 15/minutes, temperature 37°C (98.6°F) Gen Poorly-groomed, thin woman looks stated age Neuro Folstein Mini Mental Status Exam score 16/30 disoriented to month, date, and day of week, clinic name and floor poor registration with impaired attention and shortterm memory recalled 0 out of 3 items good language skills but problems with commands CT Scan Mild to moderate generalized cerebral atrophy... 

MRI and CT scan Both reveal a pituitary tumor approximately 5 mm in diameter. 

Evaluation Perform computed tomography (CT) scan and MRI for evaluation of acute event. Perform magnetic resonance angiography for asymptomatic infarction. Perform transcranial Doppler to detect abnormal velocity and identify high-risk patients. Perform electroencephalography if there is a history of seizure. 

Imaging studies also may help to identify anatomic localization of the infection. These studies usually are performed in conjunction with other tests to establish or rule out the presence of an infection. X-rays are performed commonly to establish the diagnosis of pneumonia, as well as the severity of disease (single versus multilobe involvement). CT scans are a type of x-ray that produces a three-dimensional image of the combination of soft tissue, bone, and blood vessels. In contrast, MRI use electromagnetic radio waves to produce two- or three-dimensional images of soft tissue and blood vessels with... 

CSF findings consistent with bacterial meningitis Negative CT scan of the head... 

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