Computerised tomography

Correction for beam hardening artefacts in computerised tomography... 

Hammersberg, P., Techniques for the determination of the optimal performance of high resolution computerised tomography, in Department of Mechanical Engineering. 1997, Linkbping. p. 173. 

In fig. 2 an ideal profile across a pipe is simulated. The unsharpness of the exposure rounds the edges. To detect these edges normally a differentiation is used. Edges are extrema in the second derivative. But a twofold numerical differentiation reduces the signal to noise ratio (SNR) of experimental data considerably. To avoid this a special filter procedure is used as known from Computerised Tomography (CT) /4/. This filter based on Fast Fourier transforms (1 dimensional FFT s) calculates a function like a second derivative based on the first derivative of the profile P (r) ... 

Lucey, J.V., Costa, D.C., Busatto, G., Pilowsky, L.S., Marks, I.M., Ell, P.J., and Kerwin, R.W. (1997). Caudate regional cerebral blood flow in obsessive-compulsive disorder, panic disorder and healthy controls on single photon emission computerised tomography. Psychiatry Res 74 25-33. 

Eaton WW, Kessler RC, Wittchen ElU, et al Panic disorder and panic in the United States. Am J Psychiatry 151 413-420, 1994 Ebadi MS, Simmons VJ, Hendrickson MJ, et al Pharmacokinetics of lithium and its regional distribution in rat brain. Eur J Pharmacol 27 324-329, 1974 Ebert D, Feistel H, Kaschka W, et al Single photon emission computerised tomography assessment of cerebral dopamine D2 receptor blockade in depression before and after sleep deprivation—preliminary results. Biol Psychiatry 35 880-885, 1994... 

Computerised tomography (CT) images can be enhanced by inhaled xenon and 133Xe has been widely used to measure regional cerebral blood flow. Several studies have shown increases in cerebral blood flow during xenon inhalation in both volunteers and patients with head injury. Xenon anaesthesia is probably unsuitable in the presence of intracranial disease. Xenon-enhanced CT scanning is said to be safe, provided the lungs are hyperventilated to prevent an increase in intracranial pressure. 

Pilowsky, L. S., Costa, D. C., Ell, P. J., Verhoeff, N. P., Murray, R. M., Kerwin, R. W. 1994, D2 dopamine receptor binding in the basal ganglia of antipsychotic-free schizophrenic patients. An 123I-IBZM single photon emission computerised tomography study, Br.J.Psychiatry, vol. 164, no. 1, pp. 16-26. 

Mrs KT, a 52-year-old hospital cleaner, is admitted as an inpatient to your oncology ward with symptoms from advanced colon cancer. Her GP referred her to the hospital oncology team three weeks ago for investigations (including colonoscopy and subsequent biopsy of a colonic mass, as well as whole body computerised tomography (CT) scan) that revealed stage IV metastatic colon cancer. Her consultant oncologist has now admitted her for FOLFOX systemic cytotoxic chemotherapy treatment. 

I Enhanced amphetamine-induced release of DA inpatients with schizophrenia compared with controls using single photon emission computerised tomography (SPECT) imaging, implies presynaptic DA system abnormalities in schizophrenia (Fig. 3.3). 

Introduction 193 Development 193 Vascular Supply 195 Radiographs 195 Ultrasound Assessment 195 Computerised Tomography (CT)... 

It is important to understand the fracture patterns that alter with age. Initially radiographs will be obtained for skeletal trauma with MR imaging and computerised tomography (CT) being used as appropriate. 

Computerised tomography (CT) is particularly valuable in the assessment of transitional (triplane, juvenile Tillaux) and intraarticular fractures wdiere the magnitude of displacement - both fracture gap and intraarticular or physeal step - is critical in determining whether or not operative intervention is required. CT is also extremely useful in helping the surgeon to plan the surgical approach in these situations. 

Routine radiographs for foot trauma are the anteroposterior (AP), oblique and true lateral views. Fractures are more readily identified on the AP or oblique but a true lateral allows full assessment of displacement. Both computerised tomography (CT) and magnetic resonance (MR) imaging have roles to play in foot trauma. CT is useful in comminuted calcaneal fractures to assess joint involvement and to help plan surgical reconstruction, while MR can help diagnose ligament injuries. 

Tartaro A, Larici AR, Antonucci D, Merlino B, Colosimo C, Bonomo L (1998) Optimisation and diagnostic accuracy of computerised tomography with tridimensional spiral technique in the study of craniostenosis. Radiol Med (Torino) 96 10-17... 

Pancreas A 16-year-old girl with acute myeloid leukaemia took oral voriconazole for nasal cavity aspergillosis 12 days later, severe epigastric pain followed with elevated serum amylase (234 lU/mL) and computerised tomography indicated pancreatitis [27 ]. Azole-associated pancreatitis was suspected and voriconazole stopped. Amylase normalised within 12 days. 

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