Adaptive Statistical Iterative Reconstruction Algorithm for Measurement of Vascular Diameter on Computed Tomographic Angiography In Vitro:

Computed tomography angiography in patients with active gastrointestinal bleeding

Gastrointestinal bleeding represents a common medical emergency, with considerable morbidity and mortality rates, and a prompt diagnosis is essential for a better prognosis. In such a context, endoscopy is the main diagnostic tool; however, in cases where the gastrointestinal hemorrhage is massive, the exact bleeding site might go undetected. In addition, a trained professional is not always present to perform the procedure. In an emergency setting, optical colonoscopy presents limitations connected with the absence of bowel preparation, so most of the small bowel cannot be assessed. Scintigraphy cannot accurately demonstrate the anatomic location of the bleeding and is not available at emergency settings. The use of capsule endoscopy is inappropriate in the acute setting, particularly in the emergency department at night, and is a highly expensive method. Digital angiography, despite its high sensitivity, is invasive, presents catheterization-related risks, in addition to its low availability at emergency settings. On the other hand, computed tomography angiography is fast, widely available and minimally invasive, emerging as a promising method in the diagnostic algorithm of these patients, being capable of determining the location and cause of bleeding with high accuracy. Based on a critical literature review and on their own experience, the authors propose a computed tomography angiography protocol to assess the patient with gastrointestinal bleeding.

Effect of iterative reconstruction algorithms on peripheral MDCT angiography virtual histology plaque volumes: have we been overestimating disease burden?

Our objective was to compare plaque volumes of multidetector computed tomographic images reconstructed using adaptive statistical iterative reconstruction (ASIR), model-based iterative reconstruction (MBIR), and filtered back projection (FBP). We reviewed 25 patients for a total of 50 extremities imaged on the same scanner. Calcified plaque FBP volume (3468.2 ± 2634.8 mm(3)) was higher than ASIR (2548.1 ± 2166.5 mm(3)). Calcified plaque FBP volume was higher than MBIR (mean=2345.7 ± 1935.4 mm(3)). Our findings suggest that traditional FBP methods overestimate disease compared to newer reconstruction methods.