Imaging techniques in improving image quality of CT abdomen: What are the latest?.

Abstract

Learning objectives: The aim of this exhibit is to review various latest imaging techniques that can improve the image quality and diagnostic utility of CT abdomen. Background(s): According to the American College of Radiology Appropriateness criteria, post contrast computed tomography of the abdomen and pelvis (CTAP) is the imaging modality of choice in many clinical situations, including blunt abdominal trauma, acute abdominal pain, suspected abdominal abscess and inflammation, and in the detection and surveillance of neoplastic conditions. Superior CT image quality allows improved diagnostic accuracy of these conditions and more appropriate management. CTAP image quality is defined by contrast resolution, spatial resolution, image noise, and artefacts. Appropriate CT scanning parameters at correct radiation dose settings are important. The abdominal organ and pathology assessment can be further limited by a) bodily and breathing motion, b) beam-hardening artifact from calcifications and devices and c) poor contrast opacification of organs. The aim of this exhibit is to review various latest imaging techniques that can improve the image quality and diagnostic utility of CTAP. Imaging Findings OR Procedure Details: Latest techniques that are available: A) Adopting water equivalent diameter for radiation dose appropriation instead of weight based protocols for optimal image noise reduction. B) Reducing CT rotation time improves temporal resolution that minimizes the bodily and breathing motion artefacts. C) Lowering KVp increases contrast visibility in organs. D) Model-based iterative reconstruction and knowledge-based iterative reconstruction help to reduce image noise and calcium blooming artifact, and improve low subject contrast organ visibility. E) Utilization of fine-focal spot in CT x-ray tube improves organ and lesion margin clarity and reduces calcium blooming artifact by minimizing the penumbra effect of x-ray. F) Liver detection algorithm re-distributes more radiation to the lower subject contrast organs for improved clarity. G) Dual energy can optimizes contrast opacification by lowering KeV and removes calcium and metal artefacts. H) Single photon metal artifact reduction technique removes metal artifact from coils, clips and adjacent prosthesis to allow improved view. With these techniques, the organ and lesion contours and definitions can be improved. Less motion and beam-hardening artefacts from calcifications and surgical devices allow accurate assessment of abdominal pathology. Conclusion(s): CT technology is rapidly advancing. Many latest CT imaging techniques are becoming readily available that improves the diagnostic quality of CTAP at the appropriate lowest possible radiation dose. These enhance the accuracy of abdominal pathology assessment, particularly in the acute settings.