Impedance phlebography, or impedance plethysmography (IPG), is a non-invasive medical test that measures small changes in electrical resistance of the chest, calf or other regions of the body. These measurements reflect blood volume changes, and can indirectly indicate the presence or absence of venous thrombosis. This procedure provides an alternative to venography, which is invasive and requires a great deal of skill to execute adequately and interpret accurately.
For the chest, the technique was developed by NASA to measure the split second impedance changes within the chest, as the heart beats, to calculate both cardiac output and lung water content. This technique has progressed clinically (often now called BioZ, i.e. biologic impedance, as promoted by the leading manufacturer in the US) and allows low cost, non-invasive estimations of cardiac output and total peripheral resistance, using only 4 skin electrodes, oscillometric blood pressure measurement and lung water volumes with minimal removal of clothing in physician offices having the needed equipment.
For leg veins, the test measures blood volume in the lower leg due to temporary venous obstruction. This is accomplished by inflating a pneumatic cuff around the thigh to sufficient pressure to cut off venous flow but not arterial flow, causing the venous blood pressure to rise until it equals the pressure under the cuff. When the cuff is released there is a rapid venous runoff and a prompt return to the resting blood volume. Venous thrombosis will alter the normal response to temporary venous obstruction in a highly characteristic way, causing a delay in emptying of the venous system after the release of the tourniquet. The increase in blood volume after cuff inflation is also usually diminished.
Health science – Medicine · Surgery · Vascular surgery and other vascular procedures (ICD-9-CM V3 38–39, ICD-10-PCS 03–6)
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Incision, excision,
and occlusion
of vessels |
Peripheral arterial occlusive disease: Balloon embolectomy · Thrombectomy
Carotid stenosis: Endarterectomy (Carotid endarterectomy)
Varicose veins: Ambulatory phlebectomy · Laser ablation · Sclerotherapy · Vein stripping
Venous cutdown
Temporal artery biopsy
Arteriotomy · Phlebotomy
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Other operations
on vessels |
Shunt/bypass
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Peripheral arterial occlusive disease: Peripheral arterial bypass surgery
Portal hypertension: Transjugular intrahepatic portosystemic shunt (TIPS) · Distal splenorenal shunt procedure
Vascular grafting (Human umbilical vein graft)
Blalock–Taussig shunt
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Repair
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Aortic aneurysm / dissection: Open AAA repair · Endoluminal AAA repair (EVAR)
Peripheral arterial occlusive disease: Angioplasty with/out Stenting
Atherectomy
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Auxiliary to
heart surgery
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Cardiopulmonary bypass · Cardioplegia · Extracorporeal membrane oxygenation
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Other
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Carotid stenosis: Carotid stenting
Hemodialysis/Hemofiltration · Revascularization
Glomectomy
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Medical imaging |
Angiography (Digital subtraction angiography, Cerebral angiography, Aortography, Fluorescein angiography, Radionuclide angiography, Magnetic resonance angiography)
Venography (Portography) · Impedance phlebography
Intravascular ultrasound · Carotid ultrasonography
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Other diagnostic |
Angioscopy · Ankle brachial pressure index · Tilt table test
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M: VAS
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anat(a:h/u/t/a/l,v:h/u/t/a/l)/phys/devp/cell/prot
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noco/syva/cong/lyvd/tumr, sysi/epon, injr
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proc, drug(C2s+n/3/4/5/7/8/9)
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Medical testing : Medical imaging · Radiology · (ICD-9-CM V3 87–88, ICD-10-PCS B, CPT 70010–79999)
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X-ray/
medical radiography/
Industrial radiography |
2D
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Medical: Pneumoencephalography · Dental radiography · Sialography · Myelography · CXR (Bronchography) · AXR / KUB · DXA/DXR · Upper gastrointestinal series/Small bowel follow-through/Lower gastrointestinal series · Cholangiography/Cholecystography · Mammography · Pyelogram · Cystography · Arthrogram · Hysterosalpingography · Skeletal survey · Angiography (Angiocardiography, Aortography) · Venography · Lymphogram
Industrial: Radiographic testing
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3D / XCT
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Medical: CT pulmonary angiogram · Cardiac CT · Abdominal and pelvic CT (Virtual colonoscopy) · CT angiography · CT head · pQCT · Spiral computed tomography · High resolution CT · Whole body imaging (Full-body CT scan) · Electron beam tomography
Industrial: Industrial CT Scanning
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Other
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Fluoroscopy
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MRI |
MRI of brain and brain stem · MR neurography · Cardiac MRI/Cardiac MRI perfusion · MR angiography · MR cholangiopancreatography · Breast MRI
Functional MRI · Diffusion MRI
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Ultrasound |
Echocardiography / Doppler echocardiography (TTE · TEE) · Intravascular · Gynecologic · Obstetric · Echoencephalography · Transcranial doppler · Abdominal ultrasonography · Transrectal · Breast ultrasound · Transscrotal ultrasound · Carotid ultrasonography
Contrast-enhanced · 3D ultrasound · Endoscopic ultrasound · Emergency ultrasound (FAST · Pre-hospital ultrasound) · Duplex
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Radionuclide |
2D / scintigraphy
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Cholescintigraphy · Scintimammography · Ventilation/perfusion scan · Radionuclide ventriculography · Radionuclide angiography · Radioisotope renography · Sestamibi parathyroid scintigraphy · Radioactive iodine uptake test · Bone scintigraphy · Immunoscintigraphy
full body: Octreotide scan · Gallium 67 scan · Indium 111 WBC scan
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3D / ECT
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SPECT (gamma ray): SPECT of brain, Myocardial perfusion imaging
PET (positron): Brain PET, Cardiac PET, PET mammography, PET-CT
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Optical laser |
Optical tomography (Optical coherence tomography) · Confocal microscopy · Endomicroscopy
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Thermography |
Breast thermography
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