Optimized contrast volume for dynamic CT angiography in renal transplant patients using a multiphase CT protocol

• Published in: European journal of radiology 2011-12, Vol.80 (3), p.692-698
• Main Authors: Helck, A, Bamberg, F, Sommer, W.H, Wessely, M, Becker, C, Clevert, D.A, Notohamiprodjo, M, Reiser, M, Nikolaou, K
• Format: Article
• Language: English
• Subjects: Adult; Aged; Angiography - methods; Biological and medical sciences; Cardiovascular system; Contrast Media - administration & dosage; Contrast volume reduction; Dynamic CTA; Female; Humans; Investigative techniques, diagnostic techniques (general aspects); Kidney Transplantation - diagnostic imaging; Male; Medical sciences; Middle Aged; Multiphase renal CTA; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Radiographic Image Enhancement - methods; Radiology; Renal transplant; Reproducibility of Results; Sensitivity and Specificity; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the urinary system; Tomography, X-Ray Computed - methods; Ultrasonography
• ISSN: 0720-048X; 1872-7727
• DOI: 10.1016/j.ejrad.2010.10.010

Abstract Objectives To study the feasibility of an optimized multiphase renal-CT-angiography (MP-CTA) protocol in patients with history of renal transplantation compared with Doppler-ultrasound (DUS). Methods 36 Patients underwent both DUS and time-resolved, MP-CTA (12 phases), with a mean contrast-volume of 34.4 ± 5.1 ml. Quality of MP-CTA was assessed quantitatively (vascular attenuation) and qualitatively (grades 1–4, 1 = best). For the assessment of clinical value of MP-CTA, cases were grouped into normal, macrovascular (arterial/venous) and microvascular complications (parenchymal perfusion defect). DUS served as the standard of reference. Results Using the best of 12 phases in each patient, optimal attenuation was 353 ± 111 HU, 337 ± 98 HU and 164 ± 51 HU in the iliac arteries, renal arteries, and renal veins, respectively. Mean image quality was 1.1 ± 0.3 ( n = 36) and 2.1 ± 0.6 ( n = 30) for the transplant renal arteries and veins, respectively. Six renal veins were non-diagnostic in MP-CTA. In 36 patients, MP-CTA showed 13 vascular complications and 10 parenchymal perfusion defects. DUS was not assessable in eight patients. Overall, MP-CTA showed 15 cases with pathology (42%) not identifiable with DUS. The mean effective radiation dose of the MP-CTA protocol was 13.5 ± 5.2 mSv. Conclusion MP-CTA can be sufficiently performed with reduced contrast volume at reasonable radiation dose in renal transplant patients, providing substantially higher diagnostic yield than DUS.