Transcript IMAGE MANIPULATION

IMAGE MANIPULATION
IMAGE MANIPULATION

THOSE TECHNIQUES OR PROCESSES
WHICH MODIFY AN IMAGE OR GROUP
OF IMAGES TO ENHANCE THE
VISIBILITY OF USEFUL INFORMATION
WHILE SUPPRESSING NOISE OR NONUSEFUL INFO.
WINDOWING

POINT PROCESSING TECHNIQUE
WINDOWING SYNONYMS:




CONTRAST ENHANCEMENT
CONTRAST STRETCHING
HISTOGRAM MODIFICATION
HISTOGRAM STRETCHING
MOST COMMON IMAGE PROCESSING TECHNIQUE IN CT
CONTRAST MANIPULATION
WINDOW WIDTH – WW

CONTROLS CONTRAST IN CT
LARGE NUMBER – LOW CONTRAST
LONG SCALE OF CONTRAST
WIDE LATITTUDE
WINDOW LEVEL - WL
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CONTROLS DENSITY IN CT
LARGE NUMBER – HIGH DENSITY
OBJECTS WITH CT# BELOW WL WILL GET DARKER
WW – 2000, WL 0
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CT # 0
+ 1000
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CT # 0
- 1000
MIDPOINT - O
WINDOW WIDTH
WW
WW
CT # RANGES VARY IN
SCANNERS


-1000 TO + 3095
-2048 TO + 6143
WW & WL
+3071
WW
-1024
WW & WL
+3071
WW
-1024
WW & WL
+3071
WW
-1024
WW MANIPULATION
LUNG
LIVER
PELVIS
NARROW
WW
LUNG
LIVER
PELVIS
WW MANIPULATION
LUNG
LIVER
PELVIS
MEDIUM
WW
LUNG
LIVER
PELVIS
WW MANIPULATION
LUNG
LIVER
PELVIS
WIDE
WW
LUNG
LIVER
PELVIS
WL MANIPULATION
WL
-1000
LUNG
LIVER
+1000
PELVIS
WL MANIPULATION
-1000
LUNG
WL
LIVER
+1000
PELVIS
WL MANIPULATION
-1000
WL
LUNG
+1000
LIVER
PELVIS
WW - WIDE
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400- 2000 FOR TISSUES OF GREATLY
DIFFERING ATTENUATION WITHIN THE
IMAGE
BODY SCANS- 350-600 WW
LUNG – 1000-2000 WW
BONE – 1000 – 2000 WW
WW - NARROW
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50-350 FOR DIFFERENT TISSUES OF
SIMILAR DENSITIES WITHIN THE IMAGE
BRAIN - 80-150 WW
LIVER – 100 - 250 WW
WL – WINDOW LEVEL
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SHOULD BE CENTERED NEAR THE
AVERAGE ATTENUATION OF THE
TISSUES OF INTEREST
BODY – 0 TO 60 WL
LUNG- -600 TO -800
CONTRAST vs WW
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WW
CONTRAST
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WW
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MEDIUM WW – CONTRAST OPTIMIZED
CONTRAST
WL 0, WW –1,000
500
-500
500
0
1000
+500
WL +100, WW 800
400
-300
400
+100
800
+500
WL -100, WW 600
300
-400
300
-100
600
+300
WW –
350-600
400
40
WL –
0 - 60
WW –
350-600
400
40
WL –
0 - 60
WW –
350-600
400
40
WL –
0 - 60
WW –
350-600
400
40
WL –
0 - 60
WW –
350-600
600
40
WL –
0 - 60
WW –
350-600
600
40
WL –
0 - 60
WW –
80-150
80
40
WL –
0 - 60
WW –
80-150
140
40
WL –
0 - 60
WW –
80-150
150
60
WL –
0 - 60
WW –
400-2000
1500
-600
WL –
-600 TO -750
WW –
400-2000
1500
500
WL –
400-800
WW –
400-2000
1500
500
WL –
400-800
WW –
400-2000
1500
500
WL –
400-800
WW –
400-2000
1500
500
WL –
400-800
DUAL WINDOW DISPLAY
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DIFFERENT WW & WL
PROVIDES WELL DEFINED CONTOURS
TO SEPARATE TWO DIFFERENT
ANATOMICAL AREAS
VISUALIZATION TOOLS
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MULTIPLE
WINDOWS
IMAGE MAGNIFICATION
DISTANCE AND ANGLE
COORDINATES
HIGHLIGHTING
CT HISTOGRAM
ROI
ROI AND MAGNIFICATION