US Time-Harmonic Elastography for the Early Detection of Childhood Glomerulonephritis

Glomerulonephritis (GN) comprises a group of renal diseases characterized by glomerular and tubulointerstitial fibrosis secondary to glomerular inflammation and proliferation of the basement membrane, mesangial cells, or capillary endothelium triggered by immunologic mechanisms.(1) The glomerular filtration rate decreases with progression of chronic kidney disease (CKD), ultimately resulting in end-stage renal failure. Glomerulonephritis is the third most common cause of end-stage renal failure. Initial clinical signs of glomerulonephritis are nonspecific and subtle. Occasionally, affected patients present with hypertension, proteinuria, hematuria, raised serum creatinine level, weight gain, edema, or nephrotic syndrome.(2) The underlying pathologic changes are partly irreversible, and a prompt diagnosis with early initiation of treatment is of vital importance. The diagnosis is based on clinical, laboratory, and conventional US findings, whereas renal biopsy is considered the reference standard for a definitive diagnosis and fibrosis grading.(3,4) Unfortunately, this invasive procedure is associated with the risk of serious bleeding complications and therefore is not the method of choice for longitudinal monitoring.

Elastography, a Novel imaging modality that estimates tissue stiffness, especially for superficial organs such as the breast and Thyroid. In recent years, ultrasound elastography (UE) has been demonstrated in the liver and has been applied widely in the diagnosis and evaluation of liver diseases, such as chronic hepatitis, alcoholic liver diseases, and non alcoholic fatty liver diseases.(5,6) To date, renal allograft stiffness (elasticity) has been evaluated by magnetic resonance elastography (MRE) and ultrasound elastography (UE). However, UE application for native renal diseases has not been well up till now.(7) Conventional renal ultrasonography may be appropriate to evaluate kidney size, as well as to assess the echogenicity of the renal cortex, exclude obstruction, and determine the extent of fibrosis. However, It has no significant role in diagnosis of GN. US time-harmonic elastography depicts abnormal renal stiffness in glomerulonephritis, particularly among patients with early disease and preserved renal function.(8,9,10)