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PubMed This is a summary of 16 peer-reviewed journal articles Updated
Nephrology

Getting an Accurate Diagnosis: Imaging and Criteria

At a Glance

ADPKD is primarily diagnosed using ultrasound based on the Pei-Unified criteria, which considers age and cyst count. MRIs offer more precise cyst detection and measure Total Kidney Volume (TKV) to predict disease progression. Genetic testing is used for atypical cases or family planning.

Diagnosing ADPKD is not just about finding cysts; it is about looking at those cysts in the context of your age and family history. Because it is common for healthy people to develop a few “simple” kidney cysts as they age, doctors use specific, evidence-based rules to ensure an accurate diagnosis [1][2].

The Gold Standard: Ultrasound Criteria

For most people, an ultrasound is the first tool used for diagnosis because it is safe, widely available, and does not use radiation. Doctors use the Pei-Unified criteria to determine if the number of cysts is high enough to confirm ADPKD in someone with a family history of the disease [2].

Because ADPKD is progressive, the “cutoff” number for a diagnosis changes as you get older [2]:

  • Ages 15–39: At least 3 cysts total (in one or both kidneys combined) [2].
  • Ages 40–59: At least 2 cysts in each kidney [2].
  • Ages 60+: At least 4 cysts in each kidney [2].

If you do not have a known family history, the bar for diagnosis is higher—usually 10 or more cysts in each kidney are needed to distinguish ADPKD from normal aging [1][3].

When MRI is the Better Choice

While ultrasound is great for a basic diagnosis, an MRI (Magnetic Resonance Imaging) is much more sensitive. It can detect tiny cysts that an ultrasound might miss, which is especially important for younger patients (under age 40) or those with the slower-progressing PKD2 gene [4][2].

More importantly, MRI is the preferred tool for measuring Total Kidney Volume (TKV) [5]. TKV is not just a measurement of size; it is a “biomarker” that helps your doctor predict how quickly your kidney function might decline in the future [6][7]. This measurement helps place you into a Mayo Imaging Classification (risk categories 1A through 1E), which determines if you are a candidate for certain treatments [6][8].

The Role of Genetic Testing

In about 10-15% of cases, imaging alone isn’t enough [9]. Your doctor might recommend genetic testing if:

  • You have no family history of the disease [9].
  • Your imaging results are “atypical” (for example, cysts are only in one kidney or are very unevenly distributed) [9][10].
  • You are a young person (under 30) who wants to donate a kidney and needs to be 100% sure you don’t carry the gene [11][9].
  • You are planning a family and want to discuss options for preventing transmission [12][13].

Completeness Checklist: Your Imaging Report

When you receive your radiology report, check for these specific details. If they are missing, you may want to ask your nephrologist for a more detailed review:

  • [ ] Total Kidney Volume (TKV): Ideally height-adjusted (HtTKV).
  • [ ] Kidney Dimensions: Length, width, and thickness of each kidney [14].
  • [ ] Cyst Description: Are the cysts “simple” or “complex” (containing blood or protein)?
  • [ ] Extrarenal Findings: Does the report mention cysts in the liver or pancreas [15]?
  • [ ] Complications: Any mention of kidney stones, calcifications, or unusual blood vessel patterns [14]?
  • [ ] Atypical Features: Does the imaging follow a “typical” pattern (Class 1) or an “atypical” pattern (Class 2)? (Atypical patterns often grow more slowly) [16].

Common questions in this guide

How many cysts do you need to be diagnosed with ADPKD?
The number of cysts required for an ADPKD diagnosis depends on your age and family history. Using the Pei-Unified criteria for those with a family history, individuals ages 15 to 39 need at least 3 cysts total, while those 60 and older need at least 4 in each kidney.
Why might my doctor order an MRI instead of an ultrasound for ADPKD?
While an ultrasound is a great initial tool, an MRI is more sensitive and can detect tiny cysts that an ultrasound might miss. An MRI is also the preferred method for measuring your Total Kidney Volume (TKV), which helps doctors predict how your disease will progress.
Is genetic testing required to diagnose ADPKD?
Most people are diagnosed using imaging alone, but genetic testing is recommended in about 10-15% of cases. It is typically used if you have no family history, your imaging results are unusual, or you are planning a family or kidney donation.
What is Total Kidney Volume (TKV) and why does it matter?
Total Kidney Volume is a measurement of your kidneys' overall size, usually obtained through an MRI. It acts as an important biomarker that helps your doctor determine your Mayo Imaging Classification and predict how rapidly your kidney function may decline in the future.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on my age and the number of cysts seen on my ultrasound, do I meet the Pei-Unified criteria for a definitive diagnosis?
  2. 2.What was my Height-Adjusted Total Kidney Volume (HtTKV), and which Mayo Clinic risk class (1A-1E) does that place me in?
  3. 3.If we only used ultrasound, is there a chance we missed smaller cysts that an MRI might have detected?
  4. 4.Given my family history (or lack thereof), would genetic testing help clarify my diagnosis or predict how fast my disease might progress?
  5. 5.Were there any 'complex' cysts, stones, or signs of infection noted in the 'extra findings' section of my report?

Questions For You

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References

References (16)
  1. 1

    Kidney enlargement and multiple liver cyst formation implicate mutations in PKD1/2 in adult sporadic polycystic kidney disease.

    Fujimaru T, Mori T, Sekine A, et al.

    Clinical genetics 2018; (94(1)):125-131 doi:10.1111/cge.13249.

    PMID: 29520754
  2. 2

    The diagnostic accuracy of ultrasound and genomic tests for the diagnosis of autosomal-dominant polycystic kidney disease: a systematic mapping review.

    Harnan S, Gittus M, Falzon L, et al.

    Clinical kidney journal 2025; (18(7)):sfaf187 doi:10.1093/ckj/sfaf187.

    PMID: 40697969
  3. 3

    Clinical significance of incidentally discovered renal cysts in pediatric patients.

    Botwin A, Phewplung T, Wu K, et al.

    Abdominal radiology (New York) 2019; (44(8)):2835-2840 doi:10.1007/s00261-019-02017-z.

    PMID: 30972430
  4. 4

    MRI in autosomal dominant polycystic kidney disease.

    Zhang W, Blumenfeld JD, Prince MR

    Journal of magnetic resonance imaging : JMRI 2019; (50(1)):41-51 doi:10.1002/jmri.26627.

    PMID: 30637853
  5. 5

    A rapid high-performance semi-automated tool to measure total kidney volume from MRI in autosomal dominant polycystic kidney disease.

    Simms RJ, Doshi T, Metherall P, et al.

    European radiology 2019; (29(8)):4188-4197 doi:10.1007/s00330-018-5918-9.

    PMID: 30666443
  6. 6

    Hemorrhagic Cysts and Other MR Biomarkers for Predicting Renal Dysfunction Progression in Autosomal Dominant Polycystic Kidney Disease.

    Riyahi S, Dev H, Blumenfeld JD, et al.

    Journal of magnetic resonance imaging : JMRI 2021; (53(2)):564-576 doi:10.1002/jmri.27360.

    PMID: 32969110
  7. 7

    Burden of Proof for Tolvaptan in ADPKD: Did REPRISE Provide the Answer?

    Mustafa RA, Yu ASL

    Clinical journal of the American Society of Nephrology : CJASN 2018; (13(7)):1107-1109 doi:10.2215/CJN.00190118.

    PMID: 29653956
  8. 8

    Intrafamilial Variability of ADPKD.

    Lanktree MB, Guiard E, Li W, et al.

    Kidney international reports 2019; (4(7)):995-1003 doi:10.1016/j.ekir.2019.04.018.

    PMID: 31317121
  9. 9

    Many lessons still to learn about autosomal dominant polycystic kidney disease.

    Orr S, Sayer JA

    Journal of rare diseases (Berlin, Germany) 2023; (2(1)):13 doi:10.1007/s44162-023-00017-8.

    PMID: 37664187
  10. 10

    Mutation Analysis of Autosomal-Dominant Polycystic Kidney Disease Patients.

    Suzuki Y, Katayama K, Saiki R, et al.

    Genes 2023; (14(2)) doi:10.3390/genes14020443.

    PMID: 36833371
  11. 11

    KHA-CARI Autosomal Dominant Polycystic Kidney Disease Guideline: Genetics and Genetic Counseling.

    Patel C, Tchan M, Savige J, et al.

    Seminars in nephrology 2015; (35(6)):550-556.e1.

    PMID: 26718158
  12. 12

    Overview of ADPKD in Pregnancy.

    Campbell RE, Edelstein CL, Chonchol M

    Kidney international reports 2025; (10(4)):1011-1019 doi:10.1016/j.ekir.2024.12.035.

    PMID: 40303224
  13. 13

    Birth of two healthy girls following preimplantation genetic diagnosis and gestational surrogacy in a rapidly progressive autosomal dominant polycystic kidney disease case using tolvaptan.

    Peces R, Mena R, Peces C, et al.

    Clinical kidney journal 2021; (14(8)):1987-1989 doi:10.1093/ckj/sfab082.

    PMID: 34345424
  14. 14

    Reporting ADPK Disease Phenotypes on Abdominal Scans.

    Hu Z, Lane EG, Lo GC, et al.

    Kidney international reports 2025; (10(9)):2967-2976 doi:10.1016/j.ekir.2025.06.046.

    PMID: 40980645
  15. 15

    Predictors of autosomal dominant polycystic kidney disease progression: a Brazilian single-center cohort.

    Nishimoto IH, Santos AG, Bianchini JM, et al.

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    Atypical Polycystic Kidney Disease as defined by Imaging.

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    Scientific reports 2023; (13(1)):2952 doi:10.1038/s41598-022-24104-w.

    PMID: 36807559

This page explains ADPKD diagnostic imaging and criteria for educational purposes only. Always consult your nephrologist or medical team for an accurate diagnosis and interpretation of your scan results.

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