Table 2.
Radiological characteristics of good washout (relative percentage washout ≥ 40%) and poor washout (relative percentage washout < 40%) unilateral lipid-poor adrenal masses
| Good washout | Poor washout | |||||
|---|---|---|---|---|---|---|
| Pheochromocytoma (n = 15) | Others (n = 10) [lipid-poor adenoma (n = 9), ACC (n = 1)] |
P-value | Pheochromocytoma (n = 20) | Others (n = 27) [Lipid poor adenoma (n = 4),ACC (n = 14), Infiltration (n = 9)] |
P value | |
| Largest diameter (cm) | 6.0 (3.8-7.7) | 3.4 (2.9-3.8) | .001a | 5.8 (5.3-6.9) | 8.6 (3.9-11.9) | .135 |
| Left/right | 6/9 | 6/4 | .428 | 10/10 | 11/16 | .566 |
| Necrosis (%) | 11/15 (73.3) | 3/10 (30) | .049a | 13/20 (65) | 19/27 (70.4) | .758 |
| Hemorrhage (%) | 1/15 (6.7) | 0/10 (0) | 1.000 | 1/20 (5) | 2/27 (7.4) | 1.000 |
| Calcification (%) | 2/15 (13.3) | 1/10 (10) | 1.000 | 1/20 (5) | 4/27 (14.8) | .377 |
| Enhancement patterns (HU) | ||||||
| Plain | 34.7 (32.5-37.4) | 27.7 (19.5-35.6) | .080 | 40.9 (35.7-46.5) | 37.7 (33.3-42.2) | .102 |
| Arterial | 173.2 (123.1-207.6) | 74.5 (63.6-81.2) | <.001a | 99.2 (78.1-135.1) | 59.2 (49.0-71.4) | <.001a |
| Venous | 137.2 (107.5-143.9) | 89.5 (78.5-96.5) | <.001a | 90.1 (75.3-109.6) | 69.7 (60.7-79.1) | .001a |
| Delayed | 67.6 (54.3-78.1) | 47.2 (34.9-53.4) | <.001a | 61.6 (58.6-70.1) | 58.2 (50.4-63.2) | .013a |
| Washout patterns (%) | ||||||
| APW | 65.0 (58.9-69.3) | 68.9 (61.3-73.9) | .397 | 53.5 (38.8-63.8) | 43.7 (28.3-61.0) | .237 |
| APW > 60% | 11/15 (73.3) | 8/10 (80) | 1.000 | 7/20 (35) | 8/27 (29.6) | .758 |
| RPW | 45.6 (43.4-48.7) | 44.5 (40.9-52.9) | .605 | 26.9 (22.2-35.2) | 22.3 (11.8-25.8) | .009a |
| Indices | ||||||
| PAE (%) | 341.3 (264.4-526.0) | 162.1 (110.2-211.0) | <.001a | 129.7 (90.4-234.0) | 49.3 (28.7-109.6) | <.001a |
| PVE (%) | 260.8 (228.9-311.6) | 215.5 (158.0-358.5) | .367 | 96.0 (78.5-196.1) | 79.8 (60.7-117.2) | .030a |
| Aortic arterial (HU) | 245.6 (179.8-302.4) | 263.3 (218.6-308.4) | .428 | 269.7 (223.6-289.5) | 251.1 (216.8-330.5) | .591 |
| Arterial HU of mass/aorta | 0.675 (0.531-0.841) | 0.282 (0.232-0.315) | <.001a | 0.418 (0.266-0.498) | 0.241 (0.187-0.303) | .001a |
| Arterial HU > venous HU by ≥5 (%) | 13/15 (86.7) | 2/10 (20) | .002a | 13/20 (65) | 5/27 (18.5) | .002a |
| Arterial HU > venous HU by ≥10 (%) | 12/15 (80) | 1/10 (10) | .001a | 11/20 (55) | 4/27 (14.8) | .005a |
Data is expressed as n/N (%) or median (interquartile range)
Abbreviations: ACC, adrenocortical carcinoma; APW, absolute percentage washout; HU, Hounsfield unit; PAE, percentage arterial enhancement; PFMN, plasma free metanephrine; PFNMN, plasma free normetanephrine; PVE, percentage venous enhancement; RPW, relative percentage washout.
a P < .05 is considered clinically significant.