Article Figures & Data
Figures
- FIGURE 1.
Sequential subtraction images of normal study. Liver (top arrow) and large vessel (bottom arrow) activities can be faintly visualized.
- FIGURE 2.
(Top) Conventional 99mTc-labeled RBC scintigrams demonstrating diffuse ascending colon accumulation of radiopharmaceutical without identification of specific bleeding site. Focal accumulation of radiopharmaceutical in transverse colon may suggest bleeding origin with rapid retrograde movement of blood into ascending colon. (Bottom) SSS demonstrates proximal ascending colon bleeding source that precedes the transverse colon accumulation.
- FIGURE 3.
Cross section through phantom apparatus simulating bleed locations in background (1), superimposed on liver (2), and superimposed on IVC (3).
- FIGURE 4.
Schematic representation of RSS. Each individual frame has subtracted from it the initial reference frame.
- FIGURE 5.
Schematic representation of SSS. Each individual frame has subtracted from it the preceding frame.
- FIGURE 6.
Schematic representation of ASSS. Each new frame is produced by subtraction of the preceding frame from the subsequent frame.
- FIGURE 7.
Bleed rate of 0.5 mL·min−1 with 10-s sampling interval. Interpretation with CS at 60 min is probably equivocal, especially if one were not aware of precisely where bleed was expected. However, RSS at just 21 min provides “probably present” outcome for IVC bleed position.
- FIGURE 8.
Bleed rate of 1.0 mL·min−1 with 5-min sampling interval. Lack of certainty exists for this IVC bleed position in CS frames 2 and 3 (left images). However, RSS (frame 2 – frame 1) and ASSS (frame 3 – frame 1) provide “definitely present” outcome. In this example, RSS and SSS produce the same subtraction image.
- FIGURE 9.
Bleed rate of 1.0 mL·min−1 with 5-min sampling interval. Lack of certainty exists for this liver bleed position in CS frame 2 (top left image). However, RSS (frame 2 – frame 1), SSS (frame 2 – frame 1), and ASSS (frame 3 – frame 1) provide “definitely present” outcome.
Tables
- TABLE 1
Comparison of Maximum and Minimum Counts and Ratios for Structures from Clinical Database with Those from Phantom*
Parameter Clinical minimum–maximum (phantom) Clinical mean (95% CI) P (mean vs. phantom) Liver counts/pixel 135.6−365.6 (212.8) 230.3 (112.7−348.0) 0.70 IVC counts/pixel 118.8−247.6 (167.2) 164.7 (96.4−233.0) 0.92 Background counts/pixel 39.8−122.0 (70.0) 72.8 (25.9−119.8) 0.87 Liver-to-IVC ratio 1.0−1.9 (1.3) 1.40 (0.95−1.86) 0.56 Liver-to-background ratio 2.6−4.8 (3.0) 3.38 (2.26−4.51) 0.40 IVC-to-background ratio 1.6−3.1 (2.4) 2.47 (1.78−3.16) 0.80 ↵* All phantom parameters fell within clinical range.
