An augmented patient-specific approach to administration of contrast agent for CT renal angiography

Abstract

Purpose This hybrid retrospective and prospective study performed on 200 consecutive patients undergoing renal CTA, investigates the opacification of renal vasculature, radiation dose, and reader confidence.Materials and Methods 100 patients were assigned retrospectively to protocol A and the other 100 were allocated prospectively to protocol B. Both protocols implemented a contrast material and saline flow rate of 4.5 mL/sec. Protocol A utilized a 100 mL of low-osmolar nonionic IV contrast material (Ioversol 350 mg I/mL) while protocol B employed a patient-tailored contrast media formula using iso-osmolar non-ionic (Iodixanol 320 mg I/mL).Results Arterial opacification in the abdominal aorta and in the bilateral main proximal renal arteries demonstrated no statistical significance (p>0.05). Only the main distal renal artery of the left kidney in protocol B was statistically significant (p<0.046). In the venous circulation, the IVC demonstrated a significant reduction in opacification in protocol B (59.39 HU ± 19.39) compared to A (87.74 HU ± 34.06) (p<0.001). Mean CNR for protocol A (22.68 HU ± 13.72) was significantly higher than that of protocol B (14.75 HU ± 5.76 p< 0.0001). Effective dose was significantly reduced in protocol B (2.46 ± 0.74 mSv) compared to A (3.07 ± 0.68 mSv) (p<0.001). Mean contrast media volume was reduced in protocol B (44.56 ± 14.32 mL) with lower iodine concentration. ROC analysis demonstrated significantly higher area under the ROC curve for protocol B (p< 0.0001), with inter-reader agreement increasing from moderate to excellent in renal arterial visualization.Conclusion Employing a patient-tailored contrast media injection protocol shows a significant refinement in the visualization of renal vasculature and reader confidence during renal CTA.

Acción en el manejo de reacciones anafilactoides graves relacionadas con el uso de medios de contraste yodados en tomografía computarizada

“…Es decir, diferentes estructuras anatómicas atenúan el haz RX en diversos grados. El grado de atenuación del haz RX varía de acuerdo con el número de electrones que se encuentran en el camino de este haz, dependiendo del grosor y la densidad de la estructura a estudiar, así como su número atómico (5,6). Cuando hay una diferencia considerable entre las densidades de dos órganos, como entre el músculo cardíaco y el aire en los pulmones, los límites de las estructuras se pueden visualizar en una radiografía debido al contraste natural existente (7).…”

“…Después de la inyección intravenosa, el plasma se elimina continuamente en la orina, mediante filtración glomerular sin resorción tubular. Solo el 1% del MCI sufre excreción extrarrenal (biliar, lagrimal y sudor), con mayor eliminación hepática en casos de insuficiencia renal grave (6).…”

“…En la práctica clínica, la clasificación más utilizada se basa en la osmolalidad y, en consecuencia, en la osmolaridad [6]. La primera generación de MCI consiste en monómeros iónicos osmolares altos.…”

Comparing model based iterative reconstruction to hybrid based iterative reconstruction in stenosis detection during ECG-gated coronary CTA

“…In the setting of coronary CTA, high-density structures like calci cation or stents are subject to artefacts, increased image noise and decreased image quality which can affect diagnostic performance (11)(12)(13)(14)(15). Despite extensive research, there is a lack of accurate comparison or head-to-head studies between the images produced by MBIR and the hybrid techniques.…”

Contrast media volume is significantly related to patient lung volume during CT pulmonary angiography when employing a patient-specific contrast protocol

“…[1] Since this efficacy is largely dependent on effective contrast media volume (CMV) administration, studies have been extensively conducted on contrast administration protocols. [2][3][4][5][6][7][8] These studies have found that visualization of the pulmonary vasculature is significantly improved when using a simple patientspecific formula, [1,7,9] which also allows CMV to be reduced along with the potential risk of contrastinduced nephropathy. [1] Studies performed on adult patients with normal pulmonary functioning demonstrated an air/tissue relationship approaching a 7:3 ratio of air to lung parenchyma; [10] other studies noticed that an increase in total lung volume is concomitant with an increase in the volume of pulmonary blood and pulmonary extravascular water.…”