OJRad  Vol.5 No.4 , December 2015
Discussion about Improvement of Stability of the Scan Timing by Placing Small ROI in Cerebral 3D-CTA
Abstract: In three-dimensional computed tomography angiography (3D-CTA) in our facility, we usually scan the volume of the brain according to the bolus tracking method. Fluoroscopic slice is placed at the Willis’s ring and the timing of scan is determined subjectively by a radiological technologist after strong enhancement of the basal cerebral artery is confirmed. In these procedures, however, variation of scan timing is often problematic. Therefore, we design the surpassing method to place the small region-of-interest (ROI) at the basal cerebral arteries and to start CT scan automatically. In this protocol, the fluoroscopic slices of the distal internal carotid arteries are selected referring to the precontrast volume data, small ROIs are set in bilateral internal carotid arteries, and scan trigger of CT is started automatically at the threshold of 170 HU. The maximum 80 mL of iodine contrast agent 300 mgI/mL is injected intravenously at the rate of 4.0 mL/sec, and the volume of the arterial phase is scanned automatically. We measure ROIs at the internal carotid arteries based on the obtained volume data of arterial phase and estimate the optimal scan timings from the fluoroscopic CT images reformatted at the intervals of 0.1 sec. In 38 of 53 patients, placement of the small ROIs is succeeded and automatic or manual CT scan is performed. In the patients who succeed in placement of the small ROIs, optimal scan timing of the arterial phase is obtained, while in the patients who fail placement of the small ROIs, a large variation is observed in their scan timings. Their results suggest that more stable scanning of the arterial phase is available by means of small ROI placement and automatic scanning. The clinical significance is large because the stability and reproducibility of the examination provide a quantitative analysis and more accurate diagnosis.
Cite this paper: Watanabe, Y. , Ino, K. and Yoshikawa, K. (2015) Discussion about Improvement of Stability of the Scan Timing by Placing Small ROI in Cerebral 3D-CTA. Open Journal of Radiology, 5, 224-234. doi: 10.4236/ojrad.2015.54031.

[1]   Tanabe, S., Ohtaki, M., Uede, T., Hashi, K., Suzuki, S. and Takahashi, H. (1995) Diagnosis of Ruptured and Unruptured Cerebral Aneurysms with Three-Dimensional CT Angiography (3D-CTA). Neurological Surgery, 23, 787-795.

[2]   Gonzalez-Darder, J.M., Pesudo-Martinez, J.V. and Feliu-Tatay, R.A. (2001) Microsurgical Management of Cerebral Aneurysms Based in CT Angiography with Three-Dimensional Reconstruction (3D-CTA) and without Preoperative Cerebral Angiography. Acta Neurochirurgica, 143, 673-679.

[3]   Inoue, S., Hosoda, K., Fujita, A., Ohno, Y., Fujii, M. and Kohmura, E. (2011) Diagnostic Imaging of Cerebrovascular disease on Multi-Detector Row Computed Tomography (MDCT). Neurological Surgery, 63, 923-932.

[4]   Kato, Y., Nair, S., Sano, H., Sanjaykumar, M.S., Katada, K., Hayakawa, M. and Kanno, T. (2002) Multi-Slice 3D-CTA —An Improvement over Single Slice Helical CTA for Cerebral Aneurysms. Acta Neurochirurgica, 144, 715-722.

[5]   Jayakrishnan, V.K., White, P.M., Aitken, D., Crane, P., McMahon, A.D. and Teasdale, E.M. (2003) Subtraction Helical CT Angiography of Intra- and Extracranial Vessels: Technical Considerations and Preliminary Experience. American Journal of Neuroradiology, 24, 451-455.

[6]   Watanabe, Y., Uotani, K., Nakazawa, T., Higashi, M., Yamada, N., Hori, Y., Kanzaki, S., Fukuda, T., Itoh, T. and Naito, H. (2009) Dual-Energy Direct Bone Removal CT Angiography for Evaluation of Intracranial Aneurysm or Stenosis: Comparison with Conventional Digital Subtraction Angiography. European Radiology, 19, 1019-1024.

[7]   Kumamaru, K.K., Hoppel, B.E., Mather, R.T. and Rybicki, F.J. (2010) CT Angiography: Current Technology and Clinical Use. Radiologic Clinics of North America, 48, 213-235.

[8]   Hayakawa, M., Maeda, S., Sadato, A., Tanaka, T., Kaito, T., Hattori, N., Ganaha, T., Moriya, S., Katada, K., Murayama, K., Kato, Y. and Hirose, Y. (2011) Detection of Pulsation in Ruptured and Unrupturedcerebral Aneurysms by Electrocardiographically Gated 3-Dimensional Computed Tomographic Angiography with a 320-Row Area Detector Computed Tomography and Evaluation of Its Clinical Usefulness. Neurosurgery, 69, 843-851.

[9]   Siebert, E., Bohner, G., Masuhr, F., Deuschle, K., Diekmann, S., Wiener, E., Bauknecht, H.-C. and Klingebiel, R. (2010) Neuroimaging by 320-Row CT: Is There a Diagnostic Benefitor Is It Just Another Scanner? A Retrospective Evaluation of 60 Consecutive Acute Neurological Patients. Neurological Sciences, 31, 585-593.

[10]   Tomizawa, N., Nojo, T., Akahane, M., Torigoe, R., Kiryu, S. and Ohtomo, K. (2012) Adaptive Iterative Dose Reduction in Coronary CT Angiography Using 320-Row CT: Assessment of Radiation Dose Reduction and Image Quality. Journal of Cardiovascular Computed Tomography, 6, 318-324.

[11]   Sun, Z.H., Al Moudi, M. and Cao, Y. (2014) CT Angiography in the Diagnosis of Cardiovascular Disease: A Transformation in Cardiovascular CT Practice. Quantitative Imaging in Medicine and Surgery, 4, 376-396.

[12]   Motosugi, U., Ichikawa, T., Sou, H., Morisaka, H., Sano, K. and Araki, T. (2012) Multi-Organ Perfusion CT in the Abdomen Using a 320-Detector Row CT Scanner: Preliminary Results of Perfusion Changes in the Liver, Spleen, and Pancreas of Cirrhotic Patients. European Journal of Radiology, 81, 2533-2537.

[13]   Cademartiri, F., van der Lugt A., Luccichenti, G., Pavone, P. and Krestin, G.P. (2002) Parameters Affecting Bolus Geometry in CTA: A Review. Journal of Computer Assisted Tomography, 26, 598-607.

[14]   Kirchner, J., Kickuth, R., Laufer, U., Noack, M. and Liermann, D. (2000) Optimized Enhancement in Helical CT: Experiences with a Real-Time Bolus Tracking System in 628 Patients. Clinical Radiology, 55, 368-373.

[15]   Tenjin, H., Asakura, F., Nakahara, Y., Matsumoto, K., Matsuo, T., Urano, F. and Ueda, S. (1998) Evaluation of Intraaneurysmal Blood Velocity by Time-Density Curve Analysis and Digital Subtraction Angiography. American Journal of Neuroradiology, 19, 1303-1307.

[16]   Cademartiri, F., Nieman, K., van der Lugt, A., Raaijmakers, R.H., Mollet, N., Pattynama. P.M.T., de Feyter, P.J. and Krestin, G.P. (2004) Intravenous Contrast Material Administration at 16—Detector Row Helical CT Coronary Angiography: Test Bolus versus Bolus-Tracking Technique. Radiology, 233, 817-823.

[17]   Stenzel, F., Rief, M., Zimmermann, E., Greupner, J., Richter, F. and Dewey, M. (2014) Contrast Agent Bolus Tracking with a Fixed Threshold or a Manual Fast Start for Coronary CT Angiography. European Radiology, 24, 1229-1238.

[18]   Huang, R.Y., Chai, B.B. and Lee, T.C. (2013) Effect of Region-of-Interest Placement in Bolus Tracking Cerebral Computed Tomography Angiography. Neuroradiology, 55, 1183-1188.