Renal Imaging Helps Diagnose Congenital Anomalies

State-of-the-art renal imaging modalities facilitate the early diagnosis of congenital anomalies of the kidney and urinary tract (CAKUT), according to a new study.

A comprehensive overview of new imaging technologies that have been added to the pediatric renal-imaging toolbox, conducted by researchers at the Children's Hospital of Philadelphia (CHOP; PA, USA), explores their clinical value in the anatomic and functional diagnosis and management of CAKUT and urinary tract dilation (UTD). The researchers first clarified that despite the emergence of these new technologies, renal bladder ultrasound, fluoroscopy, and nuclear-medicine functional studies remain the mainstay tools for the clinician.

New technologies include:
• Three-dimensional ultrasound (3DUS), which provides volumetric evaluation and more complete visualization of the collection system, and its emergence could result in decreased use of CT, MRI, and diuretic renography.
• Shear-wave elastography, another advanced ultrasound technique, which noninvasively measures tissue stiffness, and has potential clinical use in the assessment of chronic kidney disease, kidney allograft, and vesicoureteral reflux (VUR).
• Contrast-enhanced ultrasound (CEUS), which uses microbubbles as an intravenous ultrasound contrast agent, which can detect early features of allograft dysfunction in the setting of acute tubular necrosis, rejection, cortical necrosis and other vascular complications. It is most promising for evaluating focal renal disease.
• Contrast-enhanced voiding urosonography (CeVUS), a new radiation-free alternative to gold-standard fluoroscopic voiding cystourethrography (VCUG) for evaluating VUR and urethral pathology. CeVUS has greater sensitivity than VCUG for the detection of clinically significant VUR.
• Functional MR urography (fMRU), which can provide a comprehensive morphologic and functional evaluation of the urinary tract in a single, radiation-free examination, and is becoming the test of choice in patients with complex anatomy.
In addition, 3D-printing models have shown high accuracy in revealing complex anatomic structures and pathologies, and models of kidneys with renal tumors can enhance the understanding of surgeons, trainees, and patients and their families regarding the goals of surgery.

“Imaging modalities for diagnosing kidney and urinary tract disorders in children have developed rapidly over the last decade, largely because of advancement of modern technology. But there is a lack of knowledge of the applicability, indications, and nephrotoxic risks of novel renal imaging modalities,” concluded lead author Bernarda Viteri, MD, and colleagues. “Here we describe the clinical impact of congenital anomalies of the kidneys and urinary tract and describe pediatric-specific renal imaging techniques by providing a practical guideline for the diagnosis of kidney and urinary tract disorders.”

CAKUT make up 20% to 30% of all anomalies identified in the prenatal period and occur in up to 60% of children with chronic kidney disease in the postnatal period.

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