>Ultrasound Kidney Length

Ultrasound Kidney Length (US-KL)

US-KL alone can be used to determine whether there is risk of rapid disease progression in ADPKD.*¹

MRI is the recommended imaging modality for the most accurate and reproducible measurement of kidney length, kidney cyst burden, and TKV. As such, MRI/CT-calculated TKV is a strong predictor of future renal insufficiency in ADPKD. However, US-measured KL is a useful surrogate when MRI/CT-calculated TKV is not feasible.¹

US-measured predictor of rapid progression^† KL > 16.5 cm in patients less than 45 years old

^†when rapid progression is defined as CKD stage 3 development within 8 years^1,2

Limitations

In data analysis, KL was not normalized for height, which is an important variable.*²
US-measured KL is less accurate with larger kidneys.¹
US measurements are operator-dependent and lack precision and accuracy for detecting short-term changes in kidney volume and increase the risk of misclassifying ADPKD progression.^1,3,4
Young patients with lengths < 16.5 cm may still have rapidly progressing disease.³
Atypical patients with slow progression may have lengths > 16.5 cm.³

*Based on data analysis comparing baseline US and MRI KL measurements from the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease (CRISP)¹

ADPKD=autosomal dominant polycystic kidney disease; MRI=magnetic resonance imaging; TKV=total kidney volume; CT=computed tomography; CKD=chronic kidney disease.

References:

1. Bhutani H, et al. A comparison of ultrasound and magnetic resonance imaging shows that kidney length predicts chronic kidney disease in autosomal dominant polycystic kidney disease. Kidney Int. 2015;88:146-151.

2. Gansevoort RT, et al. Recommendations for the use of tolvaptan in autosomal dominant polycystic kidney disease: a position statement on behalf of the ERA-EDTA Working Groups on Inherited Kidney Disorders and European Renal Best Practice. Nephrol Dial Transplant. 2016;31(3):337-48.

3. Chebib FT, Perrone RD, Chapman AB, Dahl NK, Harris PC, Mrug M, Mustafa RA, Rastogi A, Watnick T, Alan SL, Torres VE. A practical guide for treatment of rapidly progressive ADPKD with tolvaptan.Journal of the American Society of Nephrology. 2018; 29(10):2458-70.

4. Magistroni R, et al. A review of the imaging techniques for measuring kidney and cyst volume in establishing autosomal dominant polycystic kidney disease progression. Am J Nephrol. 2018;48:67-78.

The information provided on the ADPKDsim website is intended for your educational benefit only. It is not intended as, nor is it a substitute for medical care or advice or professional diagnosis.

Health care professionals should use their independent judgment when reviewing the ADPKDsim's educational resources. Users seeking medical advice should consult with a health care professional.