Extraction of Fissure. Region Growing on the Fissure. Separation of Lungs lobes

Transcription

1 DETECTING LUNG FISSURES USING BAR SCANNING INTRODUCTION Lungs consists of distinct anatomic compartments called lobes. Lobes are the independent anatomic compartment. In right lung, there are three lobes and there are two lobes in left lungs. Fissures are the continues region separating the lobes of the lungs. In right lung, horizontal fissure separates the superior lobe and middle lobe. Oblique fissure separates the middle and inferior lobes. In left lung, oblique fissure separates the superior lobe and inferior lobe. As fissure separates the lobes of the lungs, it is very important to detect fissures first to detect the lobes of lungs. For a good healthy lung, fissure is continuous layer. After the extraction of continuous fissure, it separates the lungs lobes by performing region growing on the fissures. But the extraction of fissures is the most challenging task for the separation of lobes in the lungs. For the extraction of fissure, different methods are applied and the result is presented to help the future enhancement. FLOW DIAGRAM FOR DETECTING SEPARATION OF LUNGS Extraction of Fissure Region Growing on the Fissure Separation of Lungs lobes METHODS Step 1: Bar Scanning Method to Find fissure on the slice. Inputs: 2 s (Boundary of the fissure for simplicity) With the increment in X scan 3 respective pixels of Y (exact, one co-ordinate up and one co-ordinate down of the ) and check intensity. If the intensity is found on the, then Y co-ordinate for the next scan time will also be the same.

2 If the intensity is not found on the but found on one upper Y co-ordinate, then Y co-ordinate for the next scan will be this one (i.e. one upper then the previous Y) If the intensity is not found on the but found on one lower Y co-ordinate, then Y co-ordinate for the next scan will be this one (i.e. one lower than the previous Y) If the intensity is not found on the upper and lower, then the to direct according to the slope value.( up for +ve slove and down for -ve slope). If the intensities values are not found on the scan, then the gap will be joined by the straight line. Start End Case 1: Auto Driving Scan through the intensity. Start End Case 2: No Intensity Case, Takes the help of Slope or the direction of next reference. Taking increment by 2 towards the reference seems to better than that of one increment. However it varies on different position of the fissures. Step 2: Filling the Gaps by joining with Straight Line Gaps joined by line

3 For doing region growing to extract whole the fissure, closed loop is necessary. To make the closed loop the gaps are joined by the straight lines. The straight line will certainly generate some error in the position of the fissures which is ignored for this experiment. We have, Median position = (Number of element(n))/2 + 1, for the Odd number of data. Median position = (Number of element(n))/2 (+ optional 1 ) for the Even number of data. A) Scaning the intensity in different vertical position of the slice B) Accumulation of the position of the target Slice. 1,1 3,3 4,1 0, 2 1,3 3,4 4,4 3,5 C) Calculation of Median for each Y-Axis data. 0, 2 1,3 3,4 4,4 Here, optional +1 for the determination of median is done as the flow of fissure is downward. For oblique Fissure, the value of X and Y moves downward with the increase of Z. D) From the result obtained from the C, possibility of two cases are found. Boundary Case: For boundary determination first or the last position data is preferred. Left End position: 0, 2 Right End position: 4,4 Others: For normal position, median is calculated and proceed. Normal position: 0, 2 Different position of fissure can be passed and calculated as A to D for checking the accuracy.

4 Result of Method 1: Step 1 Input s: 252, 102, 151 & 370, 51, 151 Input s: 58, 90, 158 & 159, 100, 151 Right Oblique Fissure Left Oblique Fissure Input s: 261, 116, 138 & 412, 98, 138 Input s: 47, 103, 138 & 151, 112, 138

5 Step 2: Input s: 252, 102, 151 & 370, 51, 151 Input s: 58, 90, 158 & 159, 100, 151 Step 3: z = 145 z = 146 z = 139