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Purpose: To determine inter-scan, inter-reader and intra-reader variability of trabecular structure analysis using flat-panel volume computed tomography (fp-VCT) in cadaver knee specimens., Methods: Five explanted knee specimens were imaged at three different time points using fp-VCT. Four parameters that quantify trabecular bone structure of the proximal tibia were measured by two observers at two different time points. Bland-Altman analysis was used to compute the inter-scan, inter-observer and intra-observer variability., Results: Inter-scan variability was low, with a mean difference of 0% and a standard deviation less than 8.4% for each of the four parameters. The inter-observer and intra-observer variability was less than 2.8% +/- 8.5%., Conclusion: Fp-VCT is a method for assessing trabecular structure parameters with low inter-scan, inter-reader and intra-reader variability.

Flat-panel volume computed tomography (CT) systems have an innovative design that allows coverage of a large volume per rotation, fluoroscopic and dynamic imaging, and high spatial resolution that permits visualization of complex human anatomy such as fine temporal bone structures and trabecular bone architecture. In simple terms, flat-panel volume CT scanners can be thought of as conventional multidetector CT scanners in which the detector rows have been replaced by an area detector. The flat-panel detector has wide z-axis coverage that enables imaging of entire organs in one axial acquisition. Its fluoroscopic and angiographic capabilities are useful for intraoperative and vascular applications. Furthermore, the high-volume coverage and continuous rotation of the detector may enable depiction of dynamic processes such as coronary blood flow and whole-brain perfusion. Other applications in which flat-panel volume CT may play a role include small-animal imaging, nondestructive testing in animal survival surgeries, and tissue-engineering experiments. Such versatility has led some to predict that flat-panel volume CT will gain importance in interventional and intraoperative applications, especially in specialties such as cardiac imaging, interventional neuroradiology, orthopedics, and otolaryngology. However, the contrast resolution of flat-panel volume CT is slightly inferior to that of multidetector CT, a higher radiation dose is needed to achieve a comparable signal-to-noise ratio, and a slower scintillator results in a longer scanning time.

Noninvasive modalities like CTA are increasingly replacing selective angiography in the evaluation of carotid artery stenosis. Dedicated scan protocols and contrast injection techniques are mandatory for the morphological assessment of carotid artery stenosis. These protocols need to be adapted to different scanner types. The delineation of plaque components and the residual lumen is improved with high resolution scan protocols and dedicated reconstruction algorithms. The exact delineation of in-stent stenosis remains limited. Standardization of postprocessing is crucial in order to attain reproducible results. Multislice spiral CT allows reliable grading of carotid artery stenosis. Relevant venous opacification and pulsation artifacts have to be expected with 4-slice scanners, the short scan time of the latest CT scanners minimize these problems.