Scientific Session 1 — Breast Imaging: Mammography

Scientific Session 20—Neuroradiology: Technique—Brain and SpineWednesdaylarization procedures, VS demonstrated the greatest growth, with compoundedannual growth rates more than twice that of CD. DR demonstrated no netrevascularization growth. CD converted more of those who had noninvasivetests to a revascularization procedure (1/4.6) compared with VS (1/8.2).Conclusion: Our data show that CD experienced much greater PADscreening growth rates than VS or IR, which were comparable withthe “basal” DR growth rate. CD also showed substantial revascularizationprocedure volume growth, often a corollary of vascular screening.These data suggest cardiologists in particular have capitalized on anenvironment in which the self-referring endovascular specialist is doublyrewarded for PAD screening: first by reimbursement for testing, andsecond, by identifying a pool of patients eligible for revascularization,despite a lack of supporting evidence.169. Operator Dose and Position During CT FluoroscopyBerry-Tony, S. 1 *; Thornton, R. 2 ; Prins, R. 2 ; Quinn, B. 2 ; Solomon, S. 2 ;Dauer, L. 2 1. No Institutional Affiliation; 2. Memorial Sloan-KetteringCancer Center, New York, NYAddress correspondence to R. Thornton (ThorntoR@mskcc.org)Objective: To evaluate positional variation in operator radiation dose duringCT fluoroscopy.Materials and Methods: An anthropomorphic patient phantom (Real-boneSectional Phantom, Radiology Support Devices) was positioned in thegantry of a General Electric LightSpeed 16 CT scanner. CT fluoroscopy(120 kV, 60 mA, SmartStep, three images at 2.5-mm spacing) was performedat the phantom’s upper abdomen. An anthropomorphic operatorphantom (Model 702-D, CIRS) was positioned tableside 80 cm and 160cm from the gantry isocenter; 350 cm from the gantry isocenter in a positiontypical of our nurse monitoring equipment; and beside the CT gantryhousing (approximately 120 cm from gantry isocenter). Using a solid-statedosimeter (Unfors EDD-30), radiation dose rate measurements were madeat the operator’s left lens with and without leaded (0.75-mm lead equivalent)eyeglasses, at the neck with and without a 0.5-mm lead equivalentthyroid shield, on the left chest under a 0.5-mm lead equivalent apron, andat the left arm without shielding. The average of three dose rate measurementswas calculated for each data point. Reduction factors in dose ratewere calculated relative to close (80 cm) operator position.Results:Dose Rate(mR/h)at 80 cmReductionFactorat 160 cmReductionFactor at 350 cmReductionFactor BesideCT HousingLens, unshielded 47.4 3.1 24.5 23.7Lens, shielded 7.9 4.8 NDD NDDNeck, shielded 2.3 2.1 NDD NDDLeft breast, shielded 1.8 NDD NDD NDDLeft arm, unshielded 47.8 5.6 26 NDDNote—NDD = no detected dose.Conclusion: In addition to use of leaded aprons and eyewear, steppingalongside the CT unit housing during activation of CT fluoroscopy affordssubstantial incremental radiation protection to the physician operator.Scientific Session 20 —Neuroradiology: Technique—Brain and SpineWednesday, May 4, 2011Abstracts 170-177170. Correlation of Apparent Diffusion Coefficient and FractionalAnisotropy Values in the Developing Infant BrainProvenzale, J.*; Isaacson, J.; Chen, S.; Stinnett, S.; Liu, C.; Liu, C.Duke University Medical Center, Durham, NCAddress correspondence to J. Provenzale (prove001@mc.duke.edu)Objective: To correlate decrease in apparent diffusion coefficient (ADC)and increase in fractional anisotropy (FA) in various white matter (WM)regions using diffusion tensor imaging (DTI) within the first year of life.Materials and Methods: We performed DTI on 53 infants and placed regionsof interest (ROIs) within 10 WM regions important in brain development.A single observer measured ADC and FA using DtiStudio. For each region,we calculated slope of ADC as a function of FA, the correlation coefficient(r), and correlation of determination (r 2 ) before and after age correction. Weperformed a group analysis of r values and r 2 values for six WM regions primarilycomposed of crossing fibers and four regions considered to primarilyhave parallel fibers. Upon finding that a strong correlation of FA with ageexisted, we adjusted for age and calculated partial correlation coefficients.Results: Before adjusting for age, slopes of FA versus ADC ranged from–1.00711 to –1.67592 (p < .05 in all cases); r values ranged from –0.81 to–0.50 and r 2 values from 0.25 to 0.66. The four greatest r 2 values were withinWM regions presumed to have large numbers of crossing fibers and the threelowest r 2 values were in regions presumed to have predominantly parallelfibers. After adjusting for age, slopes ranged from –1.08095 to 0.09612 (p< .05 in five cases); r partial correlation coefficients ranged from –0.49 to0.03 and r 2 values from 0.31 to 0.79. The four highest r 2 values were againfound to be in WM regions presumed to have predominantly crossing fibers.However, the highest partial correlation coefficients were relatively equallydistributed between regions presumed to contain predominantly crossing fibersand those presumed to contain predominantly parallel fibers.Conclusion: In various regions, FA and ADC evolved with differing degreesof correlation. Declines in ADC and increases in FA during braindevelopment are likely influenced by numerous factors including earlyneurogenesis, fiber organization, and myelination. We found a strong influenceof age on the relationship between FA and ADC.171. There Is No Significant Correlation Between Central VenousPressure and Size of the Lateral Ventricles on Head CTShiferman, G.*; Jacobson, P.; Oyoyo, U. Loma Linda UniversityMedical Center, Loma Linda, CAAddress correspondence to G. Shiferman (genshif@yahoo.com)Objective: Normal pressure hydrocephalus (NPH) is a condition thatconsists of enlarged ventricular volume with normal lumbar punctureopening pressures. It is a form of communicating hydrocephalus in whichA64*Will present paper