Reduction of Metallic Artifacts of the Post-treatment Intracranial Aneurysms: Effects of Single Energy Metal Artifact Reduction Algorithm.

PURPOSE: This study evaluated the quality of computed tomography (CT) and CT angiography images generated using the single-energy metal artifact reduction (SEMAR) algorithm during perfusion examination in patients who had undergone reconstruction with neurosurgical clipping or endovascular coiling for treatment of aneurysms. METHODS: A total of 55 patients with implanted intracranial clips or coils (24 men and 31 women; mean age 60.15 ± 15.86 years) underwent perfusion studies evaluated by CT and CT angiography with a 320-row CT scanner. Images were reconstructed with either the SEMAR algorithm combined with iterative reconstruction (SEMAR group), or by iterative reconstruction only (non-SEMAR group control). The SEMAR and control images were compared for artifacts (index and maximum diameter), image quality, cerebral perfusion parameters, noise (images with the worst artifacts), and contrast-to-noise ratio. The metallic artifacts were visually evaluated by two radiologists using a four-point scale in a double-blinded manner. RESULTS: The noise, artifact diameter, and artifact index of the SEMAR images were significantly lower than that of the control images, and the subjective image quality score and contrast-to-noise ratio were significantly higher (P < 0.01, all). The cerebral perfusion parameters of the SEMAR and control images were comparable (i. e. blood flow, blood volume, and mean transit time). CONCLUSION: For imaging intracranial metallic implants, the SEMAR algorithm produced images with significantly fewer artifacts than the iterative reconstruction alone, with no statistical changes in perfusion parameters. Thus, SEMAR reconstruction can be instrumental in improving CT image quality and may ultimately improve the detection of postoperative complications and patient prognosis.

The 4 Quadrants: Acute Pathology in the Abdomen and Current Imaging Guidelines.

With several different imaging options available, it is not surprising that health care providers are unsure which imaging study is most appropriate for evaluating patients who present to the emergency department with abdominal pain. The American College of Radiology, currently, has appropriateness criteria for patients presenting with right upper, right lower, and left lower quadrant pain, and there are different variants for each of these quadrants. Clinicians should be aware of the American College of Radiology appropriateness criteria and, whenever possible, should be using criteria as guide to help them order the most appropriate imaging study.