Table 3:
Diagnostic utility of physiology and imaging testing in diagnosing RED
| Finding | SN (%) | SP (%) | (+) LR | (−) LR |
|---|---|---|---|---|
| BET overall3, 4, 8, 9, 13, 26, 31–45 | 66.5 (43.2–80.9) | 78.7 (68.8–89.4) | 2.7 (1.4–5.1)+ | 0.4 (0.3–0.8) |
| Inability to expel alone31–33, 35, 36, 38 | 53.8 (30.7–72.9) | 73.9 (69.1–88.5) | 2.4 (2.1–2.9) | 0.5 (0.4–0.8) |
| Weight required to expel >200g45 | 26.8 | 89.7 | 2.6 | 0.8 |
| Expulsion time >22s* 30 | 77.8 | 69.8 | 2.6 | 0.3 |
| Expulsion time >60s3, 13, 41–44 | 76.9 (74.6–87.5) | 71.4 (60.4–83.3) | 2.7 (2.5–4.2) | 0.3 (0.1–0.4) |
| Expulsion time >120s13, 34, 39, 43, 44 | 66.3 (57.1–78.3) | 86.8 (82.9–93.1) | 5.6 (4.3–7.0)+ | 0.3 (0.2–0.4) |
| Expulsion time >180s4, 9, 13, 43 | 49.3 (36.4–68.8) | 91.4 (81.8–100) | 3.5 (2.5–4.5)+ | 0.5 (0.3–0.7) |
| ARM, HR-ARM, HD-ARM any abnormality23, 27, 46–52 | 77.3 (66.7–92.9 | 76.2 (67.2–84.1) | 2.4 (2.2–4.5)+ | 0.3 (0.2–0.5) |
| ARM pr-pc and/or impaired anal relaxation27, 46, 48–50 | 84.2 (71.4–92.9) | 76.3 (71.2–78.6) | 2.4 (2.2–3.6) | 0.2 (0.1–0.3)# |
| HR-ARM, HD-ARM pr-pc and/or impaired anal relaxation23, 47, 51, 52 | 72.0 (66.7–79.7) | 78.2 (57.9–89.2) | 2.3 (1.7–3.8)+ | 0.4 (0.3–0.5) |
| Paradoxical puborectalis contraction52 | 12.4 | 77.7 | 0.6 | 1.1 |
| Impaired anal relaxation <20% baseline52 | 31.2 | 82.4 | 1.8 | 0.8 |
| Negative rectoanal pressure gradient (<–40mmHg) + high pressure band at anus23 | 32.4 | 100 | >10 | 0.7 |
| Inadequate rectal pressure <45 mmHg^* 52 | 43.0 | 81.0 | 2.3 | 0.7 |
| Type I-IV Dyssynergic Defecation23, 52 | 82.2 (79.7–84.6) | 52.9 (36.4–69.3) | 3.2 (2.2–4.3) | 0.5 (0.4–0.6) |
| Type I Dyssynergic Defecation^ 52 | 20.0 | 63.5 | 0.5 | 1.3 |
| Type II Dyssynergic Defecation^ 52 | 4.7 | 9.2 | 0.6 | 1.0 |
| Type III Dyssynergic Defecation^ 52 | 16.5 | 84.7 | 1.1 | 1.0 |
| Type IV Dyssynergic Defecation^ 52 | 45.9 | 80.0 | 2.3 | 67.6 |
| Rectal hyposensitivity$21, 53 | 52.6 (46.0–59.2) | 55.8 (42.2–69.4) | 1.6 (1.3–2.0) | 1.0 (0.8–1.1) |
| Rectosigmoid Predominance on Imaging30, 34, 54–57 | 54.4 (47.3–57.6) | 73.3 (59.2–85.1) | 1.5 (1.5–2.0)+ | 0.6 (0.6–0.8) |
| Radiopaque Markers@34, 54, 55, 57 | 56.9 (53.0–61.2) | 80.8 (68.2–91.7) | 2.0 (1.8–3.6)+ | 0.5 (0.5–0.6) |
| Scintigraphy (left sided vs. generalized delay)56 | 53.3 | 53.7 | 1.2 | 0.9 |
| CT abd/pelvis | ||||
| Rectal area on scout film >9cm2 30 | 39.5 | 73.8 | 1.5 | 0.8 |
| Rectal gas volume >20mL* 58 | 38.1 | 89.1 | 3.5 | 0.7 |
| Max rectal gas transaxial area >10cm2* 58 | 24.6 | 90.9 | 2.7 | 0.8 |
Data presented as medians (Q1, Q3)
Grey = SN/SP ≥85% with IQR <20%; (+)LR ≥2 with IQR <1.0, (−) LR ≤0.5 with IQR <0.5
Black = SN/SP ≥95% with IQR <20%, (+) LR ≥5 with IQR <1.0, (−) LR ≤0.2 with IQR <0.5
Reference numbers in brackets are found in the Supplemental reference list.
Pr-pc: puborectalis paradoxical contraction on simulated defecation
Reference 50 excluded from –LR calculation due to 100% sensitivity
SN/SP taken from documented values without raw values from reported regression analysis, thus unable to pool
Gold standard was symptomatic criteria (Rome III FC + CCCS >12) versus healthy asymptomatic controls, absolute values not available, thus unable to pool
Rectal hyposensitivity is defined as elevation of ≥1 of three rectal sensory threshold volumes beyond normal range during simple balloon distension. Thresholds for men: first sensation volume >160mL, desire to defecate volume >230mL, or max tolerated volume >315 mL in men. Thresholds for women: first sensation >120mL, desire to defecate >210mL, max tolerated volume >325mL.
Significant heterogeneity in methods used even within same modality