Accuracy of adrenal imaging modalities in predicting histological tumor dimension following adrenalectomy

Abstract

Background. Computed tomography (CT) and magnetic resonance imaging (MRI) are used for the identification of an adrenal neoplasm. Traditionally, the adrenal gland radiological size (RS) is underestimated by any preoperative imaging compared to the actual histological size (HS). The objective of the study was to investigate whether recent and more sophisticated imaging techniques can more accurately predict adrenal tumors’ size. Material and methods. We retrospectively analyzed 129 patients (86 females, 67%) with mean age 54.2 years (median: 56; range: 6 – 82), who underwent adrenalectomy (1 bilateral adrenalectomy) during the period 11/2016 to 2/2019. The 130 adrenal tumors were divided according to their RS in: A, ≤ 3 cm, B, > 3 cm and ≤ 6 cm, C, > 6 cm. Agreement between RS and HS was evaluated by the intraclass correlation coefficient (ICC). Results. In the total population, RS underestimated HS by 34% using CT or either imaging with good agreement; 28% using MRI with fair agreement. Only for RS 3 – 6cm CT, MRI or either method underestimated HS by 35% with fair agreement; for RS > 6 cm underestimation was 15% using CT, or 6% using either imaging with fair agreement. Conclusions. In defiance of the technological progress in imaging modalities, the present study confirmed previous findings that adrenal imaging by CT or MRI, cannot predict accurately the real size of adrenal tumors. In case of an adrenal incidentaloma this disagreement has a major impact not only on achieving an effective decision- making process favoring a conservative treatment or a surgical excision, but also on deciding when surgery is the option of the appropriate approach by open or laparoscopic adrenalectomy.

Keywords

• adrenal tumor
• computed tomography
• magnetic resonance imaging
• adrenalectomy