1*IN INFLAMMATORY BOWEL DISEASE, CAUSING WHITE CELL MIGRATION INTO THE LUMEN, DELAY IN IMAGING MAY RESULT IN:
-A FALSE NEGATIVE SCAN
-FALSE LOCALIZATION OF DISEASE*

2*BOTH 1-AND 3-HOUR IMAGES MUST BE POSITIVE IF AN ABNORMALITY IN THE ABDOMEN IS TO BE DIAGNOSED*

3*IN INFLAMMATORY BOWEL DISEASE WHITE CELL MIGRATE THROUGH THE WALL INTO THE LUMEN OF THE GUT DURING THE TIME COURSE OF THE STUDY (2-24 HOURS)*
*THE TYPICAL 111In-WBC SCAN APPEARANCE IN INFLAMMATORY BOWEL DISEASE IS POSITIVE UPTAKE AT 2 HOURS, WITH EITHER A NORMAL OR VERY MUCH LESS PROMINENT STUDY AT 24 HOURS*

4*THE TYPICAL 99mTc-WBC SCAN APPEARANCE IN INFLAMMATORY BOWEL DISEASE IS POSITIVE UPTAKE AT 1 AND 3 HOURS. NON-SPECIFIC BOWEL ACTIVITY MAY BE SEEN AT 24 HOURS*

5*A POSTERIOR VIEW IS VITAL TO ASSESS THE RECTUM IN PATIENTS WITH CROHN'S DISEASE. A SQUAT VIEW MAY OCCASIONALLY BE HELPFUL*

6*ON THE WBC SCAN INFLAMMATORY BOWEL DISEASE SHOWS EARLY UPTAKE OF TRACER, WITH SUBSEQUENT DISPERSION BECAUSE OF MIGRATION OF WHITE CELLS, WHEREAS AN ABSCESS WILL SHOW PROGRESSIVELY INCREASED TRACER UPTAKE OVER 24 HOURS*
*NON-SPECIFIC BOWEL ACTIVITY AT 24 HOURS WITH 99mTc-WBC SCAN MAY LEAD TO PROBLEMS OF INTERPRETATION. AND IF AN ABSCESS IS SUSPECTED, 111In-WBC SHOULD BE USED*

7*IT IS ONLY RARELY THAT AN EARLY 111In-WBC STUDY WILL BE NEGATIVE WHEN THE 24-HOURS STUDY IS POSITIVE, BUT THE 24-HOUR SCAN IS ESSENTIAL FOR FULL EVALUATION OF A SEPTIC FOCUS*

8*A FALSE NEGATIVE STUDY FOR INFECTION MAY OCCUR WHEN:
-THE PATIENT IS RECEIVING STEROIDS
-THE PATIENT IS IMMUNOSUPPRESSED BY CHEMOTHERAPY
-EFFECTIVE ANTIBIOTIC THERAPY IS BEING GIVEN*

9*THE DIFFUSE LUNG ACTIVITY AT 4 HOURS IS A COMMON OBSERVATION WITH WBC IMAGING AND IS CAUSED BY EITHER DAMAGED TO WBC DURING PREPARATION OR PHYSIOLOGICAL MARGINATION IN THE LUNG VASCULATURE*