Acoustic radiation force impulse (ARFI) elastography of adrenal glands in healthy adult dogs

A.P.R Simões,R.R Uscategui,M.C Maronezi,L.Z Crivellenti,P.D.A Silva,W.R.R Vicente,S Borin-Crivellenti,N.R.N Cruz,M.A.R Feliciano,S Fernandez,A.E Santana

doi:10.1590/1678-4162-9131

Abstract

ABSTRACT To describe the ARFI elastography in the evaluation of the adrenal glands in adult dogs, to evaluate the stiffness of adrenal parenchyma and to determine the qualitative and quantitative standards of the ARFI technique, which have not yet been described in veterinary medicine. Sixty adrenal glands from thirty healthy adult dogs were evaluated by B-mode and qualitative and quantitative ARFI elastography to assess the stiffness of healthy parenchyma and to determine the quality and quantity (shear velocity) standards of ARFI technique in body, cranial and caudal adrenal poles. Findings of ultrasonography evaluations were normal. Qualitative elastography showed that adrenal glands were not deformable and presented homogeneous middle-gray areas. The results of shear wave velocity were similar statically (P = 0.3087): 1) left adrenal - 1.42 m/s for cranial polar, 1.31 m/s for body region, and 1.71 m/s for caudal polar; 2) right adrenal - 1.42 m/s for cranial polar, 1.74 m/s for body region and 1.63 m/s for caudal pole. Quantitative and qualitative ARFI elastography of dogs' adrenal glands is feasible, well tolerated, easily implemented and may provide baseline data in the study of this structure to allow the use of ARFI.

Highlights

Ultrasonographic exam of adrenal glands has become part of abdominal scanning of canine patients with suspected endocrine disease, enabling the identification of these structures, their ultrasonographic description and biometric measurements (Cook et al 2014). This technique is described in the literature as a useful imaging modality in the diagnostic workup of canine patients with adrenal neoplasms of the cortex and medulla, hypoadrenocorticism or hyperadrenocorticism and aiding in differentiation of pituitarydependent hyperadrenocorticism (PDH) from adrenal-dependent hyperadrenocorticism (ADH) (Douglass et al 1997; Choi et al 2011; Chalus et al 2013)
In addition to the abnormalities above mentioned, ultrasonography has assisted in the detection of incidental adrenal gland lesion (IAGL), called incidentalomas, either in humans (Slapa et al 2014) and animals (Cook et al 2014), the definitive diagnosis of these lesions remains a challenge for the ultrasound technique, requiring invasive methods for diagnosis
Considering the recent applicability of acoustic radiation force impulse (ARFI) method and the reports of this type of elastography in tissue evaluation of small animals, the present study aims to describe the technique of ARFI elastography in the evaluation of the adrenal glands in adult dogs, to evaluate the stiffness of healthy adrenal parenchyma and to determine the qualitative and quantitative standards of the ARFI technique, which have not yet been described in veterinary medicine

Summary

Introduction

Ultrasonographic exam of adrenal glands has become part of abdominal scanning of canine patients with suspected endocrine disease, enabling the identification of these structures, their ultrasonographic description (echogenicity and echotexture) and biometric measurements (Cook et al 2014). This technique is described in the literature as a useful imaging modality in the diagnostic workup of canine patients with adrenal neoplasms of the cortex and medulla, hypoadrenocorticism or hyperadrenocorticism and aiding in differentiation of pituitarydependent hyperadrenocorticism (PDH) from adrenal-dependent hyperadrenocorticism (ADH) (Douglass et al 1997; Choi et al 2011; Chalus et al 2013). ARFI elastography is the technique with greater reproducibility and which shows the best accuracy with less interobserver variation, when compared to others (Feliciano et al 2014)

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