Otjen Jeffrey,  Phillips Grace,  Khatri Garvit,  Kanal Kalpana,  Kim Helen Hr,  Stanescu A. Luana

Final Pr. ID: Poster #: EDU-002

Pediatric head CT examinations remain a mainstay imaging modality, frequently utilized to evaluate a wide spectrum of pediatric pathology. Current pediatric head CT protocols aim to use the least amount of radiation while providing imaging of diagnostic quality. Lower radiation doses, along with other factors, can occasionally cause CT artifacts that can affect the quality and the interpretation of images.
In this exhibit, we review examples of physics-based, patient-based and scanner-based CT artifacts on head CT exams, while also providing a brief explanation of the underlying physics and ways to mitigate the artifact. Imaging examples include among others: apparent posterior fossa masses due to beam hardening, apparent extra-axial fluid collections due to cupping artifact, apparent brain parenchymal hypodensities concerning for infarct, and apparent beading of intracranial vessels due to lower radiation doses administered.
Awareness of these artifacts is critical for radiologists, as they can potentially lead to misdiagnosis. Read More

Authors:  Otjen Jeffrey , Phillips Grace , Khatri Garvit , Kanal Kalpana , Kim Helen Hr , Stanescu A. Luana

Keywords:  Artifacts, CT, Head

Hornsby Richard,  Brady Samuel,  Mccarville Beth,  Nett Elizabeth,  Rupcich Franco,  Blancq Terry,  Artz Nathan

Final Pr. ID: Poster #: EDU-054

This educational exhibit will review 1) challenges of CT imaging near metal, 2) current acquisition and reconstruction methods for reducing metallic artifacts, and 3) our initial experience using a GE Revolution CT system for Dual-energy scanning combined with metal artifact reduction (MAR) image reconstruction. Artifacts caused by metallic implants have limited clinical diagnoses for decades using single-energy CT (single kVp, polyenergetic beam) with standard image reconstruction. Low-energy photons in the beam are absorbed by metal, leaving only high-energy photons passing through (ie. beam hardening). Beam hardening due to metal, along with photon starvation and scatter, result in dark shading and bright/dark streaking, as well as lower signal-to-noise levels. Dual-energy CT (DECT) has demonstrated promise for beam hardening reduction because it enables reconstruction of a monoenergetic image, similar in theory to acquiring data with a monoenergetic beam. Recent developments in CT data reconstruction have also achieved better image quality near metal by mitigating shading and streaking artifacts. On our Revolution CT, MAR reconstruction is available solely in dual-energy mode. For our patients with metallic prostheses, we perform DECT and review monoenergetic images with and without MAR. MAR images typically show markedly reduced artifacts from metal and thereby improved image quality. Fig 1 displays 70 keV monoenergetic images both with and without MAR for a patient with a pacemaker. Streaking artifacts arising from the pacemaker were apparent throughout anatomy without MAR, while significantly reduced streaking and improved visualization of the aortic bifurcation is observed in the MAR reconstructed image. Images from a patient with pedicle screws and metallic rods in the spine are shown in Fig 2. Although present, shading and streaking was noticeably reduced with MAR allowing better visibility of the paraspinal soft-tissue structures and the main portal vein. On occasion, however, MAR yielded more severe artifacts for certain slices, such as in the thigh for a patient with a metallic femoral rod just above a total knee replacement (Fig 3). In summary, recent technical advancements incorporated into the Revolution CT system have improved image quality for many of our patients with metallic implants. Predicting a priori when MAR will be worse is not yet possible, so viewing monoenergetic images with and without MAR is recommended. Read More

Authors:  Hornsby Richard , Brady Samuel , Mccarville Beth , Nett Elizabeth , Rupcich Franco , Blancq Terry , Artz Nathan

Keywords:  metal artifact reduction, Dual-energy CT

Myefski Patty,  Sammet Christina

Final Pr. ID: Poster #: EDU-008 (T)

To recognize imaging artifacts that are unique to digital radiography (DR) and to learn techniques to reduce the most common image quality issues. DR systems in medical imaging have transformed planar xray, one of the oldest imaging modalities. Computed radiography (CR) and DR share some of the same image quality challenges including poor positioning, inappropriate techniques, and motion. There are image quality issues unique to DR that may be unfamiliar to new operators. Although, artifacts have been a part of imaging since the use of film-screen xray, with DR, the technologists have to be aware of new artifacts related to digital acquisition and processing. At times, pediatric DR imaging can present even bigger challenges. Technologists must learn methods to avoid DR imaging artifacts, and how to identify them before sending the image to the Picture Archiving and Communication System (PACS). This exhibit will review how to identify common DR imaging artifacts, explain the reason they occur, and suggest methods to reduce their interference with image quality. Read More

Authors:  Myefski Patty , Sammet Christina

Keywords:  Artifacts, QA

Baad Michael,  Sanchez Adrian,  Little Kevin,  Reiser Ingrid,  Lu Zheng Feng,  Feinstein Kate

Final Pr. ID: Poster #: EDU-075

1. Discuss benefits and limitations of different sonographic techniques
2. Provide phantom studies and clinical examples to demonstrate the effect of altering imaging parameters and sonographic techniques on both desired and undesired artifacts
3. Increase awareness of common errors in technique and provide recommendations to tailor the exam to the specific imaging question Read More

Authors:  Baad Michael , Sanchez Adrian , Little Kevin , Reiser Ingrid , Lu Zheng Feng , Feinstein Kate

Keywords:  Ultrasound, Imaging Artifacts, Spatial Compounding