Digital subtraction

Digital subtraction of equations (1) from (2) produces a correlation image, or shearogram. For normal illumination and viewing, the intensity profile /, of the image is given by... 

Patel SG, Collie DA, Wardlaw JM, Lewis SC, Wright AR, Gibson RJ, Sellar RJ. Outcome, observer reliability, and patient preferences if CTA, MRA, or Doppler ultrasound were used, individually or together, instead of digital subtraction angiography before carotid endarterectomy. J Neurol Neurosurg Psychiatry 2002 73(l) 21-28. 

Fig. 2.—A Portion of the Proton-decoupled, Natural-abundance, 13C-N.m.r. Spectra of Model Compound 6 and Bovine Ribonuclease B at 67.9 MHz. [(A) Compound 8 in HzO (25 mM, pH 6.5) after 8192 scans (2-s recycle-time) (B) spectrum of ribonuclease B after digital subtraction of the spectrum of ribonuclease A. (This enzyme has the same amino acid composition as ribonuclease B, but contains no carbohydrate.) Spectra were taken from Ref. 27.1...

ORC) pretreatment were digitally subtracted from the spectra acquired after the ORC. The resulting spectra in this frequency region demonstrate a smaller influence from the background and allow accurate quantitation of peak areas even at low intensity. 

FIGURE 6.20 Vibrational spectra of collagen-rich tissue. Bottom panel experimentally measured CARS spectrum (1064 nm and continuum excitation, 1064 nm probe). Middle panel experimentally measured spontaneous Raman spectrum. Top panel retrieved Raman spectrum. The acquisition time for CARS spectrum was 100 times shorter than for spontaneous Raman. The incident powers were set at approximately the same level. Autofluorescence background was digitally subtracted from experimentally measnred Raman spectrum. 

Rubenstein. E.. E,B. Hughes. L.E. Cambell, and et al. Synchrotron Radiation and Its Application to Digital Subtraction Angiography," Conf. On Digital Radiography, 314, 42, Bellingham. WA, 1981. 

Fig. 1.2. Digital subtraction angiography of a patient with basilar artery thrombosis before (left) and after (right) thrombolytic therapy. (Courtesy of Prof, von Kummer)...

Remonda L, Senn P, Barth A et al. (2002) Contrast-enhanced 3D MR angiography of the carotid artery comparison with conventional digital subtraction angiography. AJNR Am J Neuroradiol 23 213-219... 

Sundgren PC, Sun den P, Lindgren A et al. (2002) Carotid artery stenosis contrast-enhanced MR angiography with two different scan times compared with digital subtraction angiography. Neuroradiology 44 592-599... 

Fig. 18.1. Venous anatomy in digital subtraction angiography (DSA) in lateral projection. FV, frontal veins PV, parietal veins OV, occipital veins SSS, superior sagittal sinus ISS, inferior sagittal sinus TS, transverse sinus SIS, sigmoid sinus IJV, internal jugular vein SS, straight sinus CS, confluens sinuum VL, vein of I.abbe SV, sylvian vein CS, cavernous sinus VG, vein of Galen 1CV, internal cerebral vein IJV, internal jugular vein...

Fig. 18.2. a,b Normal venous anomaly in a 3D phase contrast venous angiogram performed at 1.5 T. c,d 3D phase contrast venous angiogram in a patient with idiopathic intracranial hypertension displayed in different projections. The bilateral short stenoses (arrows) are well shown by MR venography, e digital subtraction angiogram in an oblique projection. Confirmation of the obstructed vessel lumen on both sides (arrows), but the finding at this location can only be demonstrated on special projections... 

Makinen K, Manninen H, Hedman M, Matsi P, Mussalo H, Alhava E, et al. Increased vascularity detected by digital subtraction angiography after VEGF gene transfer to human lower limb artery A randomized, placebo-controlled, double-blinded phase II study. Mol Ther 2002 6 127-133. 

Fig. 6.1. Digitally subtracted arterial aragiogram showing a severe stenosis of the internal carotid artery.

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