Abstract: Objective To investigate the correlation between CT image presentations and biochemical indexes in adrenal
adenomas and pheochromocytomas. Methods We retrospectively analyzed the CT features, cortisol rhythm, supine and
orthostatic hypertension and 24-h urine methoxy in 209 patients with benign adrenal tumors. The relationship between CT
findings and the biochemical indexes were analyzed in patients with different benign adrenal tumors. Results The 209 cases
analyzed included 53 cases of cortisol adenoma, 65 cases of aldosterone adenoma, 45 cases of non-functional adenoma and 46
cases of pheochromocytomas. The plain CT scan values of the 4 groups were 17.25±1.81, 14.52±1.57, 12.20±2.05, 42.42±0.97 HU,
enhanced CT values (arterial phase) were 47.82 ± 3.07, 39.23 ± 2.37, 45.35 ± 6.46, and 104.93 ± 5.84 HU, respectively, and the
differences between CT scan and enhanced CT values were 30.58±2.29, 24.71±1.55, 33.15±5.18, and 62.51±5.73 HU, respectively.
In cortisol adenoma group, cortisol levels measured at 16:00 and 24:00 were positively correlated with plain CT scan value (r=
0.506, P=0.0001; r=0.504, P=0.0001) and enhanced CT value (r=0.514, P=0.0001; r=0.554, P=0.0001). In pheochromocytoma group,
plain scan CT value and the difference between plain and enhanced CT scan value were correlated with 24-h urine methoxy
adrenaline (ρ =0.342, 0.350; P=0.020, 0.017, respectively) and norepinephrine (ρ =0.419, 0.412; P=0.004, 0.004, respectively).
Conclusion Plain and enhanced CT scan values and their combination have important value in differential diagnosis of
adenoma and pheochromocytoma tumor, CT values combine with biochemical indexes can reduce misdiagnosis and missed
diagnosis of pheochromocytoma.