From the Guidelines
Ultrasound of the renal tract is indicated for evaluation of suspected kidney stones, urinary tract infections, hematuria, hydronephrosis, renal masses, congenital anomalies, and monitoring of chronic kidney disease, as it provides excellent visualization of kidney size, shape, and position, as well as detection of hydronephrosis, stones larger than 5mm, and masses 1.
Indications for Ultrasound Renal Tract
The primary indications for ultrasound renal tract include:
- Evaluation of obstructive uropathy and acute urinary retention 1
- Suspected kidney stones, urinary tract infections, hematuria, hydronephrosis, renal masses, congenital anomalies, and monitoring of chronic kidney disease 1
- Assessment of fetal kidney development during pregnancy and determination of obstruction in cases of acute kidney injury 1
- Evaluation of patients with flank pain, recurrent urinary tract infections, abnormal urinalysis results, or unexplained renal dysfunction 1
Advantages of Ultrasound
The advantages of ultrasound include:
- Non-invasive procedure 1
- No use of ionizing radiation 1
- Relatively inexpensive 1
- Can be performed quickly at the bedside if needed 1
- Provides excellent visualization of kidney size, shape, and position, as well as detection of hydronephrosis, stones larger than 5mm, and masses 1
Limitations of Ultrasound
The limitations of ultrasound include:
- Difficulty in detecting smaller stones 1
- Limited ability to provide detailed information about renal function 1
- Dependence on operator experience and patient's body habitus for image quality 1
Additional Imaging
For patients with persistent symptoms despite normal ultrasound findings, additional imaging such as CT may be necessary 1. CT urography provides excellent delineation of the excretory urinary tract, is very sensitive for urinary stones, readily identifies renal cortical lesions, and provides extra-urinary information 1. However, CT urography is generally more expensive than renal ultrasound and involves ionizing radiation and iodine-based IV contrast 1.
From the Research
Indications for Ultrasound Renal Tract
- Ultrasound imaging is used in the evaluation of chronic kidney disease and kidney transplantation 2
- It is used for diagnostic studies of the kidneys and lower urinary tract, and to guide percutaneous procedures such as insertion of hemodialysis catheters and kidney biopsy 3
- Ultrasound is used for initial assessment of suspected renal masses, and can distinguish cystic from solid lesions 4
- It is used to evaluate hemorrhagic renal cysts, and can characterize simple cysts from complex cysts 5
- Ultrasound is used in conjunction with plain X-ray KUB to identify urinary stone disease, and can recognize stones in the urinary tract 6
Specific Uses of Ultrasound
- Assessment of structural and functional aspects of kidneys 2
- Guidance of percutaneous procedures such as kidney biopsy 3
- Initial assessment of suspected renal masses 4
- Evaluation of hemorrhagic renal cysts 5
- Identification of urinary stone disease 6