Calibrations – Punumbra spread, Distance, Area/Volume Accuracies-
Punumbra spread = 2.4 pixels (or 1.30mm for pixel size=0.54mm) across using a 1.2mm X-ray tube-spot.
Distance – At high-contrast & 1% low-contrast edge, both accurate to 1/50th of a pixel in (delta)r (i.e. (delta)r in (delta)r/r);
and,
Area/Volume – At high-contrast & 1% low-contrast edge, accurate to 1/18th & 1/10th of a pixel respectively in (delta)r (i.e. 2(pi)r(delta)r/(pi)r2 or
(delta)(area) = 2(pi)r(delta)r (Volume = Area x Slice-thickness).
High-Contrast Resolution – Mean Modulation Transfer Function (MTF) (Reference 2) at the high-contrast edge were improved from 3.38 lp/cm to 9.61 or 10.04 lp/cm at 50% normalized modulation level after 7x or 9x magnification and enhancement respectively.
Processing-Time- 9x Magnification & enhancement of Region-of-Interest (ROI) of size of: 107x107 took 1.17 seconds by a 2.4GHz-CPU.
Figures 1 & 2 show the original coin & wire phantom image and the reduction of the penumbra effect at the guide-wire edges 'after' the enhancement.
Seven Field-Examples
(1) 30 slices of MR Angiogram at 6o apart were enhanced for clearer diagnoses and measurements of the average width of aneurysm by the indirect method using d=2x(A/(pi))1/2. Slice#14 at 84o was analyzed for demonstration. Figure 3, 4, & 5 show the original image with ROI placed on the aneurysm, the 9xROI 'before' and 'after' enhancement side-by-side, and the enhanced image with outlining annotation for the area, A in order to derive for the indirect mean width, d and plus using a software ruler for the direct maximum width measurement.
(i) A (Slice#14) = 53.66±1.07mm2. d (Slice#14)= 2x SQR(A/(pi))=8.27mm.
All 30 samples of 2007 were analyzed. Overall mean width, d=8.20±0.35mm. Figure 6 shows the distribution of the indirect mean width, d over the whole range of angles.
(ii) Direct maximum width along the elongated axis may be measured by a software ruler (Figure 5): e.g. direct maximum width at Slice#14= 9.67± 0.01mm. Nevertheless, as the elongated shape may be caused by the branching off of arteries, the measurement of the indirect mean width, d or the width orthogonal to the elongated axis plus extension along the slice-thickness direction, e.g. such as that illustrated by the following CT Angiogram, may be more appropriately used to monitor the possible growth of an aneurysm over a period of time.
{For a slide-set of animated view of all 30 analyzed slices of MR Angiogram, please refer to Personal Information for details}.
(2) 30 successive slices of CT Angiogram of 0.5mm slice-thickness were enhanced to detect the changes in width D' in Y-axis direction, which is orthogonal to the width, D in X-axis direction.
The analysis of one of the 30 slices, e.g. IMG00199 was used to demonstrate its features. Figures 7, 8 & 9 show the original image with ROI placed on an aneurysm of the anterior communicating artery, 7x ROI images of 'before' and 'after' enhancement side-by-side, and the 7x ROI enhanced image with annotations for the following measurements:-
Area (IMG00199 via profile outlining) = 59.33±1.28mm2; Width, D in X-axis = 10.22±.01mm, and Width; D' in Y-axis = 7.58±.01mm.
The elongated pear shape as shown in Figure 9 was caused by the branching of arteries in the X-axis direction. For this reason, D in X-axis was not used for the following studies.
Figure 10 is a graph plot of various Y-width, D' versus their respective slice positions (slice-thickness=0.5mm). Y-width, D' of greater than 8.00mm is highlighted in red. For the 30 images analyzed, all the D' values, which were greater than 8.00mm increased from 8.25±.01mm to 8.81±.01mm in their maximum values at the two years from 2008 to 2009. The total length in the slice-direction of D' values of greater than 8.00, increased from 3.00mm to 6.00mm for the years of 2008 to 2009 respectively. Smoothness of the graph plot indicates the good accuracy of the measurements.
(Applications for (1) & (2) – in 4D quantitative growth monitoring and the treatment decision making);
(3) CT Liver tumor- Figures 11, 12 & 13 show the original image with ROI centered on the tumor region, 7x ROI `before’ and 'after' enhancement side by side, and 7x ROI 'after’ enhancement with outlining of the tumor traced out for the statistical measurements. The surrounding tissues’ statistics were also measured for comparison. Measurements within tumor enclosure were:
Area = 88.56±1.96 mm2; Volume = Area*Slice-thickness = 885.61±19.55mm3;
Intensity within tumor = 88±14(STD) CTU;
Intensity in the surrounding tissues outside of tumor = 112±16(STD) CTU.
(Applications - diagnoses, measurements and oncology treatment monitoring (refer to Reference 3).
(4) DF Angiogram - Digital Fluorography (DF) of femoral artery
Figures 14, 15, & 16 show the original DF image with ROI, the 7xROI 'before' and 'after' enhancement side-by-side, and the enhanced image with annotations (with edge-profiles left on) for the following measurements:
In this case, a guide wire was inserted, which was used for the absolute calibration for the following measurements:
Diameter of .035J wire=2.29±0.02 pixels (=> 0.89mm);
Normal patient vessel lumen diameter=13.29±0.02 pixels=>5.17±0.01mm;
Patient vessel within stenosis cleared of blockage=5.29±0.02 pixels=>2.06 ±0.01mm.
Stenosed vessel lumen diameter=(13.29-5.29)±0.04pixels=>3.11±.02mm;
Percentage diameter stenosis of superficial femoral artery=3.11/5.17=> 60.15±0.84%.
Figures 17 and 18 show the original image with ROI on another part of the femoral artery in which no guide wire was inserted and the images of 7xROI 'before' and 'after' enhancement side-by-side. After enhancement, edges of arteries and stenosed segments became clearly visible, but without a guide wire, only relative measurements were possible.
(Applications - diagnosis and treatment planning)
(5) CT Cardiac Scan - Coronary Artery Calcium Scoring-
Coronary Artery Calcium Scoring – Measurements:-
In Image# IM00014, four regions, i.e. ROI-#1-4, were identified as the coronary arteries. They were analyzed by the CAD with their regions outlined to provide the measurements of intensity in CTU within the outlined area, its area, and its volume for Calcium Scoring assessments. Their original images with ROIs and the enhanced images with annotations for measurements are shown in Figures 19, 20a & b, & 21. The following measurements were made:
ROI# Figure# Slice# Contrast-Intensity(CTU) Area(mm2) Volume(mm3)
1) Figure 19 IM00014 404±90 7.23±0.41 21.70±1.23
2) Figure 20a IM00014 219±34 7.12±0.41 21.35±1.22
3) Figure 20b IM00014 256±57 23.42±0.74 70.27±2.21
4) Figure 21 IM00014 215±45 5.17±0.35 15.51±1.04
...........................................................................................................
Total volume=128.83±1.43 mm3
Calcium Scoring may be defined by the volume in mm3 of calcified coronary arteries of greater than the threshold of 130 HU (or CTU) in a 3mm slice (Reference 4).
The Calcium Scoring for this case study of the 3mm Image Slice# IM00014 is therefore measured by the volume of 128.83±1.43 mm3.
(Applications - diagnosis & treatment decision making)
(6) CT Lung Tumor – In Image Slice#210 of ID#162379, a small branch of tumor growth was analyzed and with the region outlined to provide the measurements of intensity in CTU within the outlined area, its area, and its volume. The original image with ROI, the 7xROI 'before' & 'after' enhancement with edge-profiles side-by-side, and 7xROI enhanced images with outlining annotation for measurements are shown in Figures 22, 23 & 24. The following measurements were made:
Intensity (mean) = 138±135(STD) CTU.
Area = 130.30±2.75mm2.
Volume = 651.52±13.75mm3.
Features of the tumor growth into the healthy tissue regions were enhanced. Clearer and sharper changes of profile edges over time may be used to prepare a semi-automatic software, which requires the diagnostic skill of the user for accurate detections and measurements of early or advanced tumor growth for the 100% success rate in the 4D screening field trial or its accurate treatment monitoring.
(Applications - 100% rate of early or advanced cancer detections and oncological treatment monitoring in 4D field trials).
(7) CT Lung TB Inflammatory Nodules analysis & measurements:
(A) In Image Slice Code #5919 of ID#160827, a mass of TB nodules at the left apex a region was analyzed and with the region outlined to provide the measurements of intensity in CTU within the outlined area, its area, and its volume. The original image with ROI, 7xROI 'before' & 'after' enhancement with edge-profiles side-by-side, and 7xROI enhanced image with outlining annotation for measurements are shown in Figures 25, 26, & 27. The following measurements were made on a mass of TB nodules:
Intensity (mean) = -74 ± 145CTU; Area = 359.65 ± 4.37mm2, Volume = 1798.26 ± 21.86mm3.
Features of the TB nodule growth were enhanced. Clearer and sharper changes of profile edges over time may be used to prepare a semi-automatic software, which requires the diagnostic skill of the user for accurate detections and measurements of early or advanced TB nodules for the 100% success rate in 4D screening field trial or its accurate treatment monitoring.
And,
(B) In Image Slice Code #5927 of ID#160827, an inflammatory TB nodule was analyzed and with the region outlined to provide the measurements of intensity in CTU within the outlined area, its area, and its volume. The original image with ROI, 7xROI 'before' & 'after' enhancement with edge-profiles side-by-side, and 7xROI enhanced images with outlining annotation for measurements are shown in Figures 28, 29, & 30. The following measurements were made of the TB nodules:
Intensity (mean) = -41 ± 106CTU; Area = 140.71±2.73mm2, , Volume = 703.53± 13.67mm3.
Features of the TB nodule growth were enhanced. Clearer and sharper changes of profile edges over time may be used to prepare a semi-automatic software, which requires the diagnostic skill of the user for accurate detections and measurements of early or advanced TB nodules for the 100% success rate in 4D screening field trial or its accurate treatment monitoring.
(Applications – 4D screening field trial measurements &/or oncological treatment monitoring).