Aims and objectives
Conventional chest x-ray (CXR) is often used as a first-step diagnostic tool as it is cheaper,
and has a reduced radiation dose as compared to standard computed tomography (CT).
CXR suffers from reduced sensitivity and carries an increased false-negative rate for many indications.
The primary advantage then of CXR with respect to patient health is the reduced radiation exposure. The effective radiation dose of an Ultra Low-Dose (ULD) CT protocol can be lowered...
Methods and materials
Projection Algorithm: Similar to Maximum Intensity Projection (MIP),
we create a thick-slab projection from thin-slice data by computing the Hounsfield Unit (HU) value at a given position (i,
k) from the HU values of the voxels at positions (i,j,k),
where ris the number of voxels satisfying: l = r*w,
l is the desired output slice thickness and wis the width of one voxel in the thin-slice data.
the resultant CT number is the maximum CT number of the...
The area under the ROC curve was measured for each assessment category (Fig 4).
The average area under the curve for each category increased by .276,
or ~45%. The mean time for interpretation and image quality score for X-rays/thoracic tomograms was 24.0s/36.9s (p=0.07), and 7.8/8.2 (p=0.16),
To have a rough comparison of the noise in the three discussed projection techniques,
a histogram was taken for a 70x70 region in the liver of an image which was processed with average...
The ROC area under the curve indicates a higher level of confidence almost across the board with a thoracic tomogram.
This was expected as a multi-slice CT offers significantly more information than CXR,
and in accordance the reading time is also increased by ~54%.
In determining whether thoracic tomograms can be a suitable replacement for CXR,
it will be prudent to assess how we value the tradeoff between confidence and interpretation time,
as well as the importance of each diagnostic...
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