Imaging of Echogenic Masses

Introduction to Imaging Modalities

The American College of Radiology recommends contrast-enhanced CT as the most commonly used modality for evaluating indeterminate masses, particularly renal masses, with a diagnostic accuracy of 79.4% for predicting renal cell carcinoma 1
Contrast-enhanced CT is strongly recommended for evaluating echogenic masses as it provides optimal characterization of enhancement patterns crucial for differentiating benign from malignant lesions 1

A multiphase CT protocol is optimal for evaluating echogenic masses, including unenhanced, corticomedullary/arterial, and nephrographic phases 1
Thin-slice acquisition (≤5mm), high tube current settings (320-340 mA), and multiplanar reconstructions are recommended for optimal imaging of echogenic masses 1

For patients with contraindications to iodinated contrast, MRI with gadolinium-based contrast is the preferred alternative, and contrast-enhanced ultrasound (CEUS) may be considered if both CT and MRI contrast are contraindicated 1
Unenhanced CT has limited utility but can still provide some information, such as characterizing homogenous masses measuring <20 HU or >70 HU as benign, and identifying certain benign lesions with macroscopic fat or calcifications and necrosis 1

Enhancement equal to or greater than normal renal cortex with washout on CT suggests malignancy in echogenic renal masses 1
Hyperechoic renal lesions measuring ≤1 cm on ultrasound are often clinically insignificant (98.1%) 1
Triple-phase CT can differentiate between solid tumors and hyperdense cysts in echogenic hepatic masses 2, 3
MRI may be superior to CT for staging intrahepatic masses 3

Small (≤1.5 cm) renal masses may show apparent enhancement due to beam hardening artifacts, particularly when surrounded by highly enhancing renal parenchyma, known as pseudoenhancement 1