Could a nonfunctional adrenal incidentaloma be a risk factor for increased carotid intima-media thickness and metabolic syndrome

BACKGROUND

This study was designed to detect the potential association of a nonfunctional adrenal incidentaloma (NFAI) with insulin resistance and associated metabolic disturbances, with a subsequent increase in cardiovascular risk factors.

METHODS

Eighty-three NFAI patients and 56 volunteers (controls) without any adrenal abnormalities on computed tomography (CT) were included. Fasting blood glucose (FBG), fasting insulin, lipid profiles, uric acid, homocysteine, fibrinogen, high sensitivity C-reactive protein (hs-CRP), and adiponectin levels were measured in both groups. Blood pressure (BP), waist circumference, body mass index (BMI), and carotid intima media thickness (CIMT) were evaluated in both the patients and volunteers.

RESULTS

There were no significant difference between the NFAI and control groups with respect to age, sex, BMI, waist circumference, systolic and diastolic BP, smoking, concomitant disease, and medications. Fasting insulin and glucose levels and homeostasis model of assessment-insulin resistance (HOMA-IR) scores were significantly higher in the NFAI group as compared with those in the control group (p<0.01). The frequency of metabolic syndrome in the NFAI group was higher than that in the control group (p<0.01). All the lipid fractions, except triglyceride (TG), (p<0.05), homocysteine (p=0.01), and fibrinogen levels (p<0.001), were significantly higher in the NFAI group as compared with the levels in the control group. There were no significant differences between the NFAI and control groups in terms of uric acid, hs-CRP, and adiponectin levels. The CIMT values in the NFAI group were significantly higher than those in the control group (0.74±0.14 vs. 0.53±0.09, p<0.001). The mean CIMT value showed a statistically positive correlation with age (r=0.245, p=0.004); the HOMA-IR score (r=0.490, p<0.001); and FBG (r=0.521, p<0.001), fasting insulin (r=0.432, p<0.001), total cholesterol (TC) (r=0.267, p=0.002), and fibrinogen (r=0.398, p<0.001) levels in the NFAI group.

CONCLUSIONS

The results indicated that the NFAI patients had an elevated risk of insulin resistance, with metabolic syndrome and increased CIMT values. Long-term follow-up studies should be designed to evaluate postsurgical alterations in metabolic parameters and cardiovascular risk factors in NFAI patients.

Using the modified Dixon technique to evaluate incidental adrenal lesions on 3T MRI

OBJECTIVES

To use the mDIXON-Quant sequence to quantify the fat fraction of adrenal lesions discovered incidentally on CT studies. To analyze the relation between the signal loss between in-phase and out-of-phase T1-weighted sequences and the fat fraction in mDIXON-Quant. To compare the sensitivity and specificity of the two methods for characterizing adrenal lesions.

MATERIAL AND METHODS

This prospective descriptive study included 31 patients with incidentally discovered adrenal lesions evaluated with 3T MRI using in-phase and out-of-phase T1-weighted sequences and mDIXON-Quant; the fat fraction of the adrenal lesions was measured by mDIXON-Quant and by calculating the percentage of signal loss between in-phase and out-of-phase T1-weighted sequences.

RESULTS

The percentage of signal loss was significantly higher in the group of patients with adenoma (61.3% ± 20.4% vs. 5.1% ± 5.8% in the group without adenoma, p<0.005). The mean fat fraction measured by mDIXON-Quant was also higher for the adenomas (26.9% ±10.8% vs. 3.4% ± 3.0%, p<0.005).The area under the ROC curve was 0.99 (0.96 - 1.00) for the percentage of signal loss and 0.98 (0.94 - 1.00) for the fat fraction measured by mDIXON-Quant. The cutoffs obtained were 24.42% for the percentage of signal loss and 9.2% for the fat fraction measured by mDIXON-Quant. The two techniques had the same values for diagnostic accuracy: sensitivity 96% (79.6 - 99.9), specificity 100% (39.8 - 100.0), positive predictive value 100% (85.8 - 100.0), and negative predictive value 80% (28.4 - 99.5).

CONCLUSION

The fat fraction measured by the modified Dixon technique can differentiate between adenomas and other adrenal lesions with the same sensitivity and specificity as the percentage of signal loss between in-phase and out-of-phase T1-weighted sequences.

Should the diagnostic and therapeutic protocols for adrenal incidentalomas be changed?

BACKGROUND

The prevalence of adrenal incidentalomas is increasing with the aging of the population and the use of high resolution imaging technics. Current protocols propose a comprehensive monitoring of their functional and morphological state, but with no conclusive clinical evidence that endorses it.

METHOD

Retrospective study of 96 patients diagnosed with adrenal incidentaloma between 2008 and 2012. We evaluated clinical, functional and imaging at baseline and during follow-up.

RESULTS

Initially, 9 cases were surgically removed: 4 due to hyperfunction (2 Cushing syndromes and 2 pheochromocytomas) and 5 due to size larger than 4cm. During follow-up one case of pheochromocytoma was diagnosed and another grew more than 1cm, needing surgery. In 98.86% of nonfunctional and benign lesions, there was no functional and/or morphological changes in the final evaluation.

CONCLUSIONS

The results of our study challenge the validity of current diagnostic-therapeutic protocols of incidentalomas, which should be reassessed in prospective studies taking into account efficiency characteristics.