DMT 161FM Microvascular Flowmeter

Overview

The DMT 161FM Microvascular Flowmeter is a precision-engineered, CMOS-based flow measurement instrument designed for quantitative assessment of luminal fluid flux in isolated microvessels and small-diameter biological tubules under controlled pressure conditions. Operating on the principle of real-time volumetric displacement detection via high-resolution CMOS sensor arrays, the 161FM delivers stable, low-drift output across dynamic flow ranges typical of resistance artery, arteriole, and capillary-level preparations. Unlike traditional electromagnetic or thermal anemometry approaches, this device eliminates calibration drift associated with temperature gradients or protein fouling—critical for longitudinal studies requiring hour-scale stability. It is specifically engineered to integrate seamlessly with the DMT Pressure-Myograph System (e.g., DMT 620M/625M platforms), enabling synchronized acquisition of lumen diameter, wall tension, intraluminal pressure, and volumetric flow rate—a foundational capability for mechanistic studies of vascular reactivity, endothelial function, and myogenic autoregulation.

Key Features

• CMOS-based optical flow sensing architecture optimized for physiological saline and plasma-compatible media
• Linear response range: 15–4000 µL/min with sub-microliter resolution and ≤±2% full-scale accuracy (typical)
• Low thermal mass design minimizes convective interference during pressure-step protocols
• Digital I/O interface compatible with DMT MyoView™ software and third-party DAQ systems (e.g., National Instruments USB-6211, PowerLab)
• Passive flow path geometry (no moving parts or internal valves) ensures biocompatibility and simplifies sterilization protocols
• Calibration traceable to NIST-traceable gravimetric standards; factory calibration certificate included

Sample Compatibility & Compliance

The 161FM supports ex vivo perfusion of isolated microvessels—including rat mesenteric arteries, cerebral penetrating arterioles, and human adipose-derived microvessels—with inner diameters ranging from 30 to 250 µm. Its flow path accommodates standard DMT 610M/620M cannulation setups using borosilicate glass micropipettes (OD 1.0 mm, ID 0.75 mm). The device complies with ISO 13485:2016 requirements for medical device accessories used in preclinical research instrumentation. While not intended for in vivo human use, its design adheres to principles outlined in ISO 14155:2020 (clinical investigation of medical devices) for benchtop validation workflows supporting GLP-compliant pharmacology studies. Data integrity meets FDA 21 CFR Part 11 expectations when used with validated DMT MyoView™ v5.2+ software featuring audit trail, electronic signatures, and secure user access control.

Software & Data Management

The 161FM interfaces natively with DMT MyoView™ software (Windows 10/11, 64-bit), which provides real-time flow waveform visualization, automated baseline correction, and synchronized parameter logging alongside pressure, diameter, and force signals. Raw flow data are exported in ASCII-delimited (.txt) or HDF5 format for downstream analysis in MATLAB, Python (via h5py), or GraphPad Prism. All acquired datasets include embedded metadata: timestamp (UTC), system ID, calibration date, operator ID, and experimental protocol identifier. Software version 5.2 introduces enhanced noise suppression algorithms for low-flow (<50 µL/min) signal fidelity and configurable event-triggered data capture (e.g., flow response onset following agonist application).

Applications

• Quantification of endothelium-dependent and -independent vasodilation in pressurized microvessels
• Evaluation of shear stress–mediated NO release kinetics under stepwise flow ramp protocols
• Assessment of microvascular permeability changes via transmural flow differentials during inflammatory challenge
• Pharmacodynamic profiling of vasoactive compounds (e.g., acetylcholine, SNP, U46619) in resistance vessels
• Validation of computational fluid dynamics (CFD) models of hemodynamic forces in bifurcating arteriolar networks
• Training and standardization of microvascular myography techniques in academic core facilities

FAQ

Is the 161FM compatible with non-DMT pressure myograph systems?
Yes—when interfaced via analog voltage output (0–10 V DC proportional to flow) or digital TTL pulses, the 161FM can be integrated with custom or third-party myograph rigs meeting standard ±10 V input compliance.
What maintenance is required between experiments?
Rinse with deionized water followed by 70% ethanol; air-dry prior to storage. No recalibration is needed unless physical impact or exposure to organic solvents occurs.
Can the 161FM measure reverse (retrograde) flow?
No—it is unidirectional and calibrated for antegrade flow only. Bidirectional measurement requires hardware revision (e.g., 161FM-BD variant, available upon request).
Does the device require external power or is it bus-powered?
It requires a dedicated 24 V DC power supply (included); USB connectivity is data-only and does not provide power.
How is flow zeroing performed?
Zero offset is established automatically during system initialization using a closed-loop nulling routine; manual zero adjustment is accessible in MyoView™ Advanced Settings for troubleshooting.