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Percutaneous sclerotherapy
Percutaneous sclerotherapy is a minimally invasive procedure that injects a sclerosing agent into varicose veins and vascular malformations, destroying the vessel lining so it scars into a fibrous cord.
Percutaneous tibial nerve stimulation
Percutaneous tibial nerve stimulation (PTNS) is a minimally invasive treatment for overactive bladder in which a needle electrode near the ankle stimulates the posterior tibial nerve.
Percutaneous tracheostomy
Percutaneous tracheostomy, also called percutaneous dilatational tracheostomy, is a bedside procedure that creates a surgical airway using needle puncture and guidewire dilation instead of open surgery.
Percutaneous transhepatic biliary drainage
Percutaneous transhepatic biliary drainage (PTBD) is an image-guided procedure in which a catheter passed through the skin and liver drains bile, relieving biliary obstruction when ERCP is unsuitable.
Percutaneous transhepatic cholangiography
Percutaneous transhepatic cholangiography (PTC) is an imaging procedure in which a needle passed through the skin and liver into the bile ducts delivers contrast for X-ray imaging.
Peretinoin
Peretinoin (NIK-333) is an oral synthetic acyclic retinoid, RAR/RXR agonist, developed as chemoprevention against hepatocellular carcinoma recurrence after curative therapy; EMA orphan drug with mixed phase III results.
Perfectionism (psychology)
Perfectionism (psychology): a personality trait of excessively high standards and overly critical self-evaluation, measured by the FMPS and HMPS scales, a transdiagnostic risk factor for eating disorders, anxiety, OCD, and depression, treatable with CBT, and rising among college students since 1989.
Perflenapent
Perflenapent (dodecafluoropentane, C5F12; EchoGen, Sonus Pharmaceuticals) is a liquid perfluorocarbon phase-shift ultrasound contrast agent. EU-approved 1998, withdrawn 2001; US NDA withdrawn 2000; superior to Albunex in phase III trials.
Perflubutane
Perflubutane (C4F10), sold as Sonazoid, is a perfluorocarbon gas used in lipid-shelled microbubble ultrasound contrast agents; first approved in Japan in 2006, it enables Kupffer-phase liver imaging and is approved in China, Japan, Korea, Norway, Singapore, and Taiwan.
Perfluorocarbon nanoemulsions
Perfluorocarbon nanoemulsions (PFC nanoemulsions) are submicrometer emulsions of inert liquid perfluorocarbon droplets in water, first studied as artificial blood and later used for 19F MRI tracers and targeted drug delivery.
Perfluorohexyloctane
Perfluorohexyloctane (F6H8) is a chemically inert semifluorinated alkane used in prescription eye drops for dry eye disease, marketed as MIEBO in the United States since 2023.
Perforated eardrum
Perforated eardrum (tympanic membrane perforation): a hole or tear in the eardrum from infection, injury, loud noise, or pressure change; usually heals within weeks to two months, with myringoplasty for persistent holes.
Perforated ulcer
Perforated ulcer (perforated peptic ulcer): a full-thickness hole in a stomach or duodenal ulcer causing peritonitis. Treated by omental (Graham) patch repair, increasingly laparoscopic; mortality 9-40%.
Perforating dermatoses
Perforating dermatoses (acquired perforating dermatosis, reactive perforating collagenosis, Kyrle disease, perforating folliculitis, elastosis perforans serpiginosa) are skin disorders marked by transepidermal elimination of collagen or elastin, mainly in diabetes and chronic kidney disease.
Perforation of duodenum
Perforation of duodenum: transmural duodenal wall injury, also called duodenal perforation. Main causes are peptic ulcer (H. pylori, NSAIDs), ERCP and other iatrogenic injury, and trauma; mortality 8-25%, higher with peritonitis.
Perforation of large intestine
Perforation of large intestine is a complete breach of the colonic wall that leaks bowel contents into the abdomen, causing peritonitis; common causes include cancer, diverticulitis, and colonoscopy injury.
Perforation of oesophagus
Perforation of oesophagus (esophageal perforation, Boerhaave syndrome when spontaneous), ICD-11 DA20.3: a hole in the oesophageal wall leaking contents into mediastinum; mostly iatrogenic, mortality about 10-15%.
Perforation of small intestine
Perforation of small intestine (ICD-11 ME24.30), also called non-traumatic small bowel perforation: full-thickness breach of the jejunal or ileal wall leaking contents into the abdomen, causing peritonitis; causes include iatrogenic injury, ischemia, malignancy, Crohn disease, and trauma.
Perforator flap
A perforator flap is a reconstructive technique in which skin and fat are transferred on small vessels piercing the muscle, sparing the muscle, most often for breast reconstruction.
Performance status
Performance status (PS), measured by the Karnofsky (KPS, 0–100) or ECOG/WHO (0–5) scales, rates cancer patients' functional ability; a strong prognostic factor and common clinical trial eligibility criterion.
Performance-enhancing substance
Performance-enhancing substance: drugs, hormones, and supplements (steroids, EPO, caffeine, creatine) used to boost athletic performance; regulated by WADA's annually updated Prohibited List under strict liability, with efficacy proven for only 5 of 23 classes.
Perfusion
Perfusion is blood flow through tissue vessels, delivering oxygen and removing carbon dioxide, quantified as ml/min/g. Covers its history (Harvey, Malpighi), autoregulation, bedside and laboratory assessment in shock, and optical, fluorescence, and imaging measurement techniques.
Perfusion computed tomography
Perfusion computed tomography (CT perfusion, CTP) is a CT technique that maps blood flow in tissue, used mainly to select acute stroke patients for reperfusion therapy.
Perfusion imaging
Perfusion imaging is a family of medical imaging techniques that measure capillary-level blood delivery using MRI, CT, or radionuclide tracers, guiding stroke, cardiac, and cancer care.
Perfusion Index
Perfusion index (PI, PPI): pulse-oximetry-derived ratio of pulsatile to non-pulsatile blood flow at the sensor site; values under 0.3% signal very low perfusion, 2–5% good perfusion; predicts fluid responsiveness and anesthetic hypotension.
Perfusion Magnetic Resonance Imaging
Perfusion MRI measures capillary-level blood delivery (ml/100 g/min) using four techniques: DSC and DCE with gadolinium contrast, and non-contrast ASL and IVIM; used for stroke, brain tumors, and dementia.
Perfusion mapping
Perfusion mapping is a family of imaging methods that measure blood flow through tissue, using MRI techniques like DSC, DCE, and ASL, plus CT perfusion.
Perfusionist
Perfusionist: allied health professional who operates the heart-lung machine (cardiopulmonary bypass) during cardiac surgery and runs ECMO and mechanical support; credentialed as CCP by the ABCP (est. 1975), with state licensure in Massachusetts, Maryland, and Texas.
Perhexiline
Perhexiline (Pexsig), a prophylactic antianginal maleate drug acting on fatty acid metabolism via CPT-1/2, requires CYP2D6-based drug monitoring; used for refractory angina in Australia and repurposed for heart failure and cancer.
Periacetabular osteotomy
Periacetabular osteotomy (PAO) is a joint-preserving operation that cuts the pelvis around the acetabulum and repositions the socket to correct hip dysplasia and delay arthritis.