K974882 · Merlin Engineering Works, Inc. · LMD · May 22, 1998 · Radiology
Device Facts
Record ID
K974882
Device Name
DOWNSCAN LT
Applicant
Merlin Engineering Works, Inc.
Product Code
LMD · Radiology
Decision Date
May 22, 1998
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 892.2020
Device Class
Class 1
Indications for Use
The intended use for DownScan LT is conversion of X-ray (stationary, Carm, angiography, etc.), nuclear medicine, magnetic resonance, and ultrasound images either directly from their source, or from an intermediate storage device (like a video tape or video disk), for use on display monitors, optical, tape or disk recorders, or other apparatus requiring a standard frame rate video signal (30 or 25 frames/second). The use of DownScan LT is indicated whenever the source and destination of a video signal are incompatible due to different line rates or other signal attributes, and a standard frame rate video signal is required. DownScan LT is intended for use in patient care areas, but is not intended to have any patient contact.
Device Story
DownScan LT is a digital video scan converter; converts high line rate medical video (1023-1125/60 or 1249/50) to standard low line rate video (525/30 or 625/25). Input sources include X-ray, C-arm, angiography, nuclear medicine, MRI, and ultrasound; outputs to display monitors or recording devices. Operates in patient care areas; used by clinical staff to ensure signal compatibility between imaging sources and recording/display hardware. Device utilizes 8-bit analog-to-digital and digital-to-analog conversion; processes signals in digital domain to preserve image quality. Benefits include enabling use of standard recording/display equipment with high-resolution medical imaging systems.
Clinical Evidence
Bench testing only. Testing verified compliance with RS-170 and RS-343A video standards. SMPTE RP-133 testing confirmed correct aspect ratio compensation and 1% low-contrast imaging resolution. No clinical data provided.
Technological Characteristics
1 3/4" EIA half-rack mount chassis; 100V-240V AC power. 8-bit analog-to-digital and digital-to-analog converters. Real-time digital signal processing. Compatible with industry standard monochrome video signals. Compliant with RS-170, RS-343A, and SMPTE RP-133 standards.
Indications for Use
Indicated for conversion of medical imaging video signals (X-ray, nuclear medicine, MRI, ultrasound) from high line rates (1023-1125/60 or 1249/50) to standard low line rates (525/30 or 625/25) when source and destination equipment are incompatible. Intended for use in patient care areas; no patient contact.
Regulatory Classification
Identification
A medical image communications device provides electronic transfer of medical image data between medical devices. It may include a physical communications medium, modems, and interfaces. It may provide simple image review software functionality for medical image processing and manipulation, such as grayscale window and level, zoom and pan, user delineated geometric measurements, compression, or user added image annotations. The device does not perform advanced image processing or complex quantitative functions. This does not include electronic transfer of medical image software functions.
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## 22 1999
Image /page/0/Picture/2 description: The image shows a sequence of handwritten characters. The characters are 'K974882'. The characters are written in black ink on a white background. The characters are all connected, and they are all the same size.
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Merlin Engineering Works 1888 Embarcadero Road, Palo Alto, CA 94303 Tel (415) 850
## Summary of Safety and Effectiveness 2.
Submitter:
Merlin Engineering Works, Inc. 1888 Embarcadero Road Palo Alto, California 94303
(650) 856-0900 Telephone: (650) 858-2302 Facsimile: Gerald Engbretson, Contact: Operations Manager and Director of Regulatory Affairs
DownScan LT
Device identification:
Model Number: ME-209 Common Name: Video Scan Converter (or Digital Scan Converter)
Trade Name:
K95398
Image Processing System Classification Name:
UniScan
Device(s) to which substantial equivalence is claimed:
Description of the device:
Intended use of the device:
DownScan 120 Merlin Engineering Works K970451 DownScan LT is a digital image processing system that can convert from high line rate video standard of 1023-1125/60 or 1249/50 to low line rate video standards of 525/30 or 625/25. Housed in a 1 3/4" EIA half-rack mount chassis, DownScan LT operates from 100V to 240V AC power.
Merlin Engineering Works
The intended use for DownScan LT is conversion of X-ray (stationary, Carm, angiography, etc.), nuclear medicine, magnetic resonance, and ultrasound images either directly from their source, or from an intermediate storage device (like a video tape or video disk), for use on display monitors, optical, tape or disk recorders, or other apparatus requiring a standard frame rate video signal (30 or 25 frames/second). The use of DownScan LT is indicated whenever the source and destination of a video signal are incompatible due to different line rates or other signal attributes, and a standard frame rate video signal is required. DownScan LT is intended for use in patient care areas, but is not intended to have any patient contact.
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Summary of how the technological characteristics compare to predicate device(s):
Summary of (nonclinical) performance tests and how their results support a determination of substantial equivalence:
Conclusions drawn from the performance tests:
DownScan LT and the predicate devices are real-time video processing systems which are designed to convert monochrome video images from one video format to another. The main difference between DownScan LT and one of the predicates (Merlin UniScan) is that DownScan LT converts video from high line rate to low line rate formats, where the predicate converts from low line to high line (upscan mode) as well as high line to low line (downscan mode). The only differences between DownScan LT and the other predicate (Merlin DownScan 120) are a varying clock frequencies and the ability of the predicate to input video at twice the standard frame rate (with the DownScan 120).
DownScan LT and the predicate devices utilize similar technology to perform their functions. These systems all convert the incoming analog video signal to digital form using 8-bit analog-to-digital converters, process the signals in the digital domain, and convert back to analog video using 8-bit digital-to-analog converters for the output.
DownScan LT was tested to ensure that it meets the appropriate requirements of RS-170 and RS-343A. The data demonstrates that the DownScan LT meets these requirements, as is the case for the predicate devices.
In addition, DownScan LT was tested in accordance with SMPTE RP-133. The system correctly compensates for aspect ratio changes, and it permits low-contrast imaging resolution at the 1% level.
DownScan LT is electrically compatible with industry standard monochrome video signals. The image quality is preserved (within the limits of standard video technology).
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Image /page/2/Picture/16 description: The image shows a logo for the U.S. Department of Health & Human Services. The logo features a stylized representation of a human figure, with three profiles overlapping to create a sense of depth and connection. The text "DEPARTMENT OF HEALTH & HUMAN - USA" is arranged in a circular pattern around the figure.
MAY 2 2 1998
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
Re:
Gerald C. Engbretson Operations Manager and Director of Reguulatory Affairs Merlin Engineering Works 1888 Embarcadero Road
K974882 Merlin DownScan LT Dated: March 24, 1998 Received: March 25, 1998 Unclassified/Procode: 90 LMD
Dear Mr. Engbretson:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to 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). You may, therefore, narket the device, subject to the general controls provisions of the Act. 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.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (OS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic OS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.
This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4613. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address "http://www.fda.gov/cdrb/dsmaldsmam.html".
Sincerely yours,
Kilian Yiu
Lillian Yin, Ph.D. Director, Division of Reproductive Abdominal, Ear, Nose and Throat and Radiological Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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510(k) Number (if known):
## Device Name: DownScan LT
Indications For Use:
The use of DownScan LT is indicated whenever the source and destination of a video signal are incompatible due to different line rates or other signal attributes, and a standard frame rate video signal (30 or 25 frames/second) is required. Examples include conversion of X-ray (stationary, C-arm, angiography, etc.), nuclear medicine, magnetic resonance, and ultrasound images either directly from their source, or from an intermediate storage device (like a video tape or video disk), for use on display monitors, optical, tape, or disk recorders, or other apparatus requiring a standard frame rate signal.
(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE)
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| Division of Reproductive, Abdominal, ENT, and Radiological Devices | |
| 510(k) Number | K974882 |
| Prescription Use <span></span> (per 21 CFR 801.109) | <span></span> |
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Over-The-Counter Use Concurrence of CDRH, Office of Device Evaluation (ODE)
(Optional Format 1-2-96)
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.