Acute Lower Gastrointestinal Bleeding: Temporal Factors Associated With Positive Findings on Catheter Angiography After (99m)Tc-Labeled RBC Scanning.
OBJECTIVE
The objective of the study was to determine if time to positive (TTP), defined as the time from the start of (99m)Tc-labeled RBC scanning to the appearance of a radionuclide blush (considered to be a positive finding for acute lower gastrointestinal bleeding [LGIB]), and lag time (LT), defined as the time from the appearance of a radionuclide blush to the start of catheter angiography (CA), affected the yield of CA for the detection of acute LGIB.


METHODS
TTP and LT were retrospectively evaluated in 120 patients who had positive findings for acute LGIB on (99m)Tc-labeled RBC scanning and subsequently underwent CA for the diagnosis and localization of gastrointestinal bleeding. Two nuclear medicine fellowship-trained radiologists independently reviewed the (99m)Tc-labeled RBC scans. Two fellowship-trained interventional radiologists independently reviewed the angiograms. All data were analyzed using SAS software.


RESULTS
When a TTP threshold of ≤ 9 minutes was used, the sensitivity, specificity, positive predictive value, and negative predictive value for a positive CA study were 92%, 35%, 27%, and 94%, respectively. In addition, the odds of detecting bleeding on CA increased 6.1-fold with a TTP of ≤ 9 minutes relative to a TTP of > 9 minutes (p = 0.020). A significant inverse relationship was found between LT and a positive CA study (p = 0.041).


CONCLUSIONS
TTP and LT impact the rate of positive CA studies. A TTP threshold of ≤ 9 minutes allows the detection of almost all patients who would benefit from CA for treatment and allows a reduction in unnecessary negative CA studies. The likelihood of positive findings on CA decreases with a delay in the performance of CA.
1 Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University, 222 Richmond St, Providence, RI 02903.
Maggie
M
Chung
2 Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI.|3 Department of Diagnostic Imaging, Division of Interventional Radiology, Rhode Island Hospital, Providence, RI.
Gregory J
GJ
Dubel
2 Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI.
Richard B
RB
Noto
2 Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI.
Don C
DC
Yoo
4 Lifespan Biostatistics Core, Rhode Island Hospital, Providence, RI.
Grayson L
GL
Baird
2 Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI.|3 Department of Diagnostic Imaging, Division of Interventional Radiology, Rhode Island Hospital, Providence, RI.
Ethan A
EA
Prince
2 Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI.|3 Department of Diagnostic Imaging, Division of Interventional Radiology, Rhode Island Hospital, Providence, RI.
Timothy P
TP
Murphy
5 Division of Diagnostic Radiology, University Hospitals Case Medical Center, Cleveland, OH.
Timothy L
TL
Haaga
2 Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI.|3 Department of Diagnostic Imaging, Division of Interventional Radiology, Rhode Island Hospital, Providence, RI.
Sun Ho
SH
Ahn
D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D006471:Gastrointestinal Hemorrhage / Q000000981:diagnostic imaging*; D006801:Humans; D008875:Middle Aged; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013671:Technetium Tc 99m Sulfur Colloid; D013997:Time Factors
D019275:Radiopharmaceuticals; D013671:Technetium Tc 99m Sulfur Colloid
RBC scan; angiography; gastrointestinal bleeding gastrointestinal hemorrhage; technetium; technetium-99m sulfur colloid