K200980 · Butterfly Network, Inc. · IYO · Jun 11, 2020 · Radiology
Device Facts
Record ID
K200980
Device Name
Auto 3D Bladder Volume Tool
Applicant
Butterfly Network, Inc.
Product Code
IYO · Radiology
Decision Date
Jun 11, 2020
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 892.1560
Device Class
Class 2
Attributes
AI/ML, Software as a Medical Device
AI Performance
Output
Algorithm
Acceptance
Observed
Dev DS
Dev Readers
Test DS
Test Readers
Bladder volume
U-Net CNN
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—
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Non-interventional validation study
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Indications for Use
The Butterfly Auto 3D Bladder Volume Tool is a software application package. It is designed to view, quantify and report results acquired on Butterfly Network ultrasound systems for noninvasive volume measurements of the bladder, to support physician diagnosis. Indicated for use in adult populations.
Device Story
Software application for Butterfly iQ ultrasound systems; performs non-invasive bladder volume measurement. Clinician acquires 25 2D B-mode ultrasound images of bladder; software uses U-Net deep learning algorithm for automatic bladder segmentation and volume calculation via integration over binary images. Output presented to clinician for diagnostic support. Used by qualified clinicians in clinical settings. Benefits include rapid, automated volume estimation to aid clinical decision-making regarding bladder function.
Clinical Evidence
Non-interventional validation study using representative patient dataset (balanced gender, typical age). Primary endpoint met. Variability testing performed for inter- and intra-operator consistency across image clips/frames. Test datasets strictly segregated from training data. Results demonstrate safety and effectiveness profile equivalent to predicate.
Technological Characteristics
Software-based bladder volume quantification. Uses U-Net convolutional neural network for image segmentation. Operates on Butterfly iQ ultrasound systems (phased array, 100-degree sector). Measurement range 0-740 mL. Accuracy: 0-100mL ±7.5mL; 100-740mL ±7.5%. Non-sterile, battery-powered, B-mode operation.
Indications for Use
Indicated for noninvasive bladder volume measurement in adult populations to support physician diagnosis. Contraindicated for fetal or pediatric use, pregnant patients, patients with ascites, or patients with open skin/wounds in the suprapubic region.
Regulatory Classification
Identification
An ultrasonic pulsed echo imaging system is a device intended to project a pulsed sound beam into body tissue to determine the depth or location of the tissue interfaces and to measure the duration of an acoustic pulse from the transmitter to the tissue interface and back to the receiver. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.
Special Controls
*Classification.* Class II (special controls). A biopsy needle guide kit intended for use with an ultrasonic pulsed echo imaging system only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.
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June 11, 2020
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Butterfly Network, Inc. % Mr. Brian Sawin Sr. Regulatory Affairs Manager 530 Old Whitfield Street GUILFORD CT 06437
Re: K200980
Trade/Device Name: Auto 3D Bladder Volume Tool Regulation Number: 21 CFR 892.1560 Regulation Name: Ultrasonic pulsed echo imaging system Regulatory Class: Class II Product Code: IYO, ITX Dated: April 8, 2020 Received: April 14, 2020
Dear Mr. Sawin:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmp/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see
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https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
For
Thalia T. Mills, Ph.D. Director Division of Radiological Health OHT7: Office of In Vitro Diagnostics and Radiological Health Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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# Indications for Use
510(k) Number (if known) K200980
Device Name Auto 3D Bladder Volume Tool
#### Indications for Use (Describe)
The Butterfly Auto 3D Bladder Volume Tool is a software application package. It is designed to view, quantify and report results acquired on Butterfly Network ultrasound systems for noninvasive volume measurements of the bladder, to support physician diagnosis. Indicated for use in adult populations.
Type of Use (Select one or both, as applicable):
| | <input checked="true" type="checkbox"/> Prescription Use (Part 21 CFR 801 Subpart D) |
|--|--------------------------------------------------------------------------------------|
| | <input type="checkbox"/> Over-The-Counter Use (21 CFR 801 Subpart C) |
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K200980
510(k) Summary or Statement
Image /page/3/Picture/2 description: The image shows the logo for Butterfly Network. The logo consists of a blue butterfly icon on the left, followed by the words "Butterfly" and "Network" in black text. The word "Butterfly" is larger and on top, while "Network" is smaller and below it.
510(k) Summary of Safety and Effectiveness
## Submitter Information
### Submitter Name and Address
Butterfly Network, Inc. 530 Old Whitfield St. Guilford, CT 06437 USA (tel.) 855-296-6188 (fax) 203-458-2514 www.butterflynetwork.com
### Contact Person
Brian Sawin Sr. Regulatory Affairs Manager 855-296-6188 bsawin@butterflynetwork.com
### Date Prepared
June 8, 2020
### Subject Device - Proprietary/Trade Name
Auto 3D Bladder Volume Tool
## Subject Device - Common Name
Diagnostic Ultrasound System with accessories
### Classification Name
| Classification Name | Regulation Number | Product Code |
|---------------------------------------|-------------------|--------------|
| Ultrasonic Pulsed Echo Imaging System | 21 CFR 892.1560 | IYO |
| Diagnostic Ultrasound Transducer | 21 CFR 892.1570 | ITX |
## Classification
Class II
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## Predicate Device:
K172356 - BladderScan Prime PLUS System. Verathon. Inc. (Clearance Date: 09/15/2017)
### Device Summary:
The Butterfly Auto 3D Bladder Volume Tool is a software application used on Butterfly iQ Ultrasound Systems to provide a non-invasive measurement of bladder volume. The system calculates the bladder volume using proprietary artificial intelligence automatic segmentation and volume measurement algorithms on Butterfly Network ultrasound systems.
The Auto 3D Bladder Volume Tool allows the clinician to calculate bladder volume when using the Bladder preset in B-mode. The tool is used to acquire 25, 2D images of the bladder. Once acquired, a volume estimate is calculated and presented back to the clinician. The clinician can then exit, restart the tool or save the acquisition to the study roll. The information presented is intended as additional input to standard diagnostic pathways and is only to be used by qualified clinicians.
The Auto 3D Bladder Volume Tool is based on the image segmentation method, U-Net', and the volume calculation is computed using the process of integration over binary images.
1. Ronneberger, Olaf, Fischer, Philipp, and Brox, Thomas. "U-net: Convolutional networks for biomedical image segmentation." International Conference on Medical image computing and computer-assisted intervention. Springer, Cham, 2015.
### Indications for Use:
The Butterfly Auto 3D Bladder Volume Tool is a software application package. It is designed to view, quantify and report results acquired on Butterfly Network ultrasound systems for noninvasive volume measurements of the bladder, to support physician diagnosis. Indicated for use in adult populations.
### Summary of Technoloqical Characteristics
The Butterfly Auto 3D Bladder Volume Tool has a substantially equivalent intended use and technological characteristics as the legally marketed predicate device. Quantification and reporting of results of bladder volume is the technological principle for both the subject and predicate devices and are used to aid in diagnosis. The subject and predicate devices are based on the following same technological elements:
- Quantification of bladder volume based on the analysis of on image segmentation data
- Identifying and outlining the bladder
- Auto-contouring of the bladder
- Reporting of bladder volume
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The following technological differences exist between the subject and predicate devices:
- The Butterfly Auto 3D Bladder Volume Tool uses the machine learning-based . algorithm, U-Net.
- o The predicate has the same intended use and provides machine learningbased algorithms for its bladder volume calculations via patented neural network technology.
A comparison of the proposed Butterfly Auto 3D Bladder Volume Tool to the currently marketed predicate device are provided in the table below:
| Comparison Category | Butterfly Auto 3D<br>Bladder Volume Tool | Predicate Verathon<br>BladderScan Prime PLUS<br>System |
|-----------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| | (This submission) | (K172356) |
| Comparison Overview | | |
| Intended Use/Indications<br>For Use | The Butterfly Auto 3D<br>Bladder Volume Tool is a<br>software application<br>package. It is designed to<br>view, quantify and report<br>results acquired on Butterfly<br>Network ultrasound<br>systems for noninvasive<br>volume measurements of<br>the bladder, to support<br>physician diagnosis.<br>Indicated for use in adult<br>populations. | The BladderScan Prime<br>System is an ultrasound<br>device intended to be used for<br>measuring the urine volume in<br>the bladder non- invasively. |
| Contraindications | The Auto 3D Bladder<br>Volume Tool is not<br>intended for fetal or<br>pediatric use or for use on<br>pregnant patients, patients<br>with ascites, or patients<br>with open skin or wounds<br>in the suprapubic region. | The BladderScan Prime<br>System is not intended for fetal<br>use or for use on pregnant<br>patients, patients with ascites,<br>or patients with open skin or<br>wounds in the suprapubic<br>region. |
| Patient/User Characteristics | | |
| Target Population | Male and Female | Male, Female, and Pediatric |
| Anatomical Site | Identical to predicate | Bladder |
| Users | Identical to predicate | Physicians/Medical<br>Professionals |
| Technological Characteristics and Performance | | |
| Technology | Identical to predicate | Neural network technology |
| Sterility | Identical to predicate | Non-sterile |
| Power Source | Identical to predicate | Battery powered |
| Energy Delivered | Identical to predicate | Ultrasound |
| Measurement Accuracy | 0-100mL = ±7.5mL<br>100-740 mL = ±7.5% | 0-100mL = ±7.5mL<br>100-999 mL = ±7.5% |
| Measurement Range | 0 to 740 mL | 0 to 999 mL |
| Modes of Operation | B-mode | B-mode |
| Transducer Type | Electronic Sector Scanning<br>(Phased Array) | Mechanical Sector Probe |
| Sector Angle | 100 degrees | 120 degrees |
| Number of Scan Planes | 25 | 12 |
| Design and Usability Features | | |
| Portable | Identical to predicate | Yes |
| Display | Identical to predicate | LCD |
| Scan Button | Identical to predicate | Yes |
| Touchscreen Operation | Identical to predicate | Yes |
| Selectable Unit Orientation<br>(Patient Right/Left) | No | Yes |
| Live Scan Image | Identical to predicate | Yes |
| Calibration | Identical to predicate | No calibration recommended |
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# Performance Data
Software Verification and Validation Testing
Software verification and validation testing were conducted, and was provided as recommended by FDA's Guidance for Industry and FDA Staff, "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices." The software for this device is considered a "moderate" level of concern, since a failure or latent design flaw could indirectly result in minor injury to the patient or operator through incorrect or delayed information or through the action of a care provider.
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## Performance Testing
Butterfly Network's Auto 3D Bladder Volume Tool software was developed and tested in accordance with company design control processes and safety and performance testing. Verification and validation testing established that the device meets its design requirements, intended use and demonstrates substantial equivalence to the predicate. A non-interventional validation study was conducted, where bladder volume was calculated. The patient dataset was constructed to provide a representative range of volume values, in a patient population with a balanced gender proportion and clinically typical age. Variability testing was also performed to demonstrate that the Auto 3D Bladder Volume Tool performs acceptably with a variety of image clips and frames from the same patient. Test datasets were strictly segregated from algorithm training datasets. The primary endpoint was met. Inter and intra-operator variability was assessed between operators processing the same images. Based on the clinical performance as documented in this study, the device has a safety and effectiveness profile that is equivalent to the predicate.
### Summary of Substantial Equivalence:
The Auto 3D Bladder Volume Tool is as safe and effective as the predicate has the same intended uses and similar indications, technological characteristics, and principles of operation as its predicate device. In addition, the minor technological differences raise no new issues of safety or effectiveness. Performance data, including software verification and validation and performance testing demonstrate that the Butterfly Auto 3D Bladder Volume Tool is safe and effective and therefore, substantially equivalent.
Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.