CT Abdomen (Non-Contrast)

Similar expressions

CT Abdomen/ Non-Contrast Abdomen/ NCCTA/ CT Abdomen and Pelvis

Introduction

CT abdomen is one of the routine examinations in diagnostic radiology. This scan is usually conducted as part of the contrast abdomen scan to compare pre and post contrast images. It can be used for surgical planning and post-surgical assessment, and urgent evaluations of abdomen and pelvis.

Patient preparation

• Explain the procedure clearly and kindly.
• Check the suitability to expose radiation.
• Ask the patient to remove metals related to the interested region.

There can be pre-preparations for patient including oral and rectal water, which depend on patient’s diagnostic needs.

Patient positioning

• Position the patient in feet first and supine.
• Center the scanning area in the scanner iso-center [6].

Explanation: this reduces overall radiation exposure and increases image quality.

• Place both hands above the head.

Explanation: this reduces streak artifacts from the hands, also it avoids unnecessary radiation exposure to the hands.

• Instruct the patient to breath in and hold during the scan.

Explanation: avoids motion un-sharpness of liver, pancreas and kidneys.

• Set scan initiation point at the nipple level of the patient.

Scan planning

• If abdomen or upper abdomen, plan the scan slab from the dome of the diagram to the upper margin of the sacroiliac joints. However, lower end point of the scan can be extended to the pelvic region according to diagnostic needs.

• If abdomen and pelvis, plan the scan slab from the dome of the diagram to a level just below the ischial tuberosities.

• Conduct the scan under arrested inspiration.

Post-processing

• Axial, coronal and sagittal images in soft-tissue window (WL 500, WW 50) with ≤ 5mm slicethickness can be generated.
• Axial, coronal and sagittal images in bone-window (WL 3500, WW 350) with ≤ 3mm slice thickness can be generated.

Reference

1. Calimano-Ramirez, L. F., Hernandez, M., Singh, A., Gumus, K. Z., Marfori, W., Virarkar, M. K., Lall, C., & Gopireddy, D. R. (2023). Quality assurance for non-contrast CT of the abdomen and pelvis during a period of supply chain disruption leading to iodinated contrast shortage in the emergency department setting.Journal of clinical imaging science, 13, 8. https://doi.org/10.25259/JCIS_142_2022
2. Payor A, Jois P, Wilson J, Kedar R, Nallamshetty L, Grubb S, Sullivan C, Fowler T. Efficacy of Noncontrast Computed Tomography of the Abdomen and Pelvis for Evaluating Nontraumatic Acute Abdominal Pain in the Emergency Department.J Emerg Med. 2015 Dec;49(6):886-92. doi: 10.1016/j.jemermed.2015.06.062. Epub 2015 Aug 22. PMID: 26306680.
3. Semaan H, Bazerbashi MF, Siesel G, Aldinger P, Obri T. Diagnostic accuracy of non-contrast abdominal CT scans performed as follow-up for patients with an established cancer diagnosis: a retrospective study.Acta Oncol. 2018 Mar;57(3):426-430. doi: 10.1080/0284186X.2017.1360512. Epub 2017 Aug 2. PMID: 28766397.
4. Kelly J, Raptopoulos V, Davidoff A, Waite R, Norton P. The value of non-contrast-enhanced CT in blunt abdominal trauma.AJR Am J Roentgenol. 1989 Jan;152(1):41-8. doi: 10.2214/ajr.152.1.41. PMID: 2783289.
5. Cao, K., Xia, Y., Yao, J., Han, X., Lambert, L., Zhang, T., Tang, W., Jin, G., Jiang, H., Fang, X., Nogues, I., Li, X., Guo, W., Wang, Y., Fang, W., Qiu, M., Hou, Y., Kovarnik, T., Vocka, M., Lu, Y., … Lu, J. (2023). Large-scale pancreatic cancer detection via non-contrast CT and deep learning. Nature medicine, 29(12), 3033–3043. https://doi.org/10.1038/s41591-023-02640-w
6. Romanyukha, A., Nzitunga, P. S., & Dolcet, A. (2022, April 28). CT patient positioning plays key role in radiation dose reduction.www.auntminnie.com.
7. Olga R. Brook, MD, Chair, Jessica Kurian MD, Alec Megibow, MD, MPH, FACR, & Michael Furman, MD. (2021). ACR–SABI–SAR–SPR practice parameter for the performance of computed tomography (CT) of the abdomen and computed tomography (CT) of the pelvis.Retrieved from www.gravitas.acr.org.