title: Modified PAIR technique for percutaneous treatment of high-risk hydatid cysts.
abstract: OBJECTIVE
  This paper presents a modification of the known method for percutaneous treatment of hydatid cyst, the PAIR technique. It aimed to achieve safe aspiration of large symptomatic cysts and cysts with a danger of impending rupture.
  
  
  METHODS
  We designed a coaxial catheter system to achieve concomitant evacuation of cyst contents while infusing scolicidal agent. Hypertonic saline is used to wash out cyst contents and to kill protoscolices. This was followed by injection of a sclerosant (ethyl alcohol 95%) into the residual cyst cavity to prevent formation of a cyst collection after the procedure. Seventeen cysts in 14 patients were successfully aspirated. Follow-up plain radiographs, ultrasonography and CT were performed weekly in the first 4 weeks and then at 3, 6 and 12 months for all patients. Seven patients (9 drained cysts) were followed up for 2 years and 1 patient for 3 years.
  
  
  RESULTS
  All cysts were successfully aspirated. The following morphologic changes were noticed: a gradual decrease in cyst size (17 cysts, 100%), thickening and irregularity of the cyst wall due to separation of endocyst from pericyst (7 cysts, 41%), development of a heterogeneous appearance of the cyst components (8 cysts, 47%) and development of pseudotumor (2 cysts, 12%). None of the treated cysts disappeared completely. No significant procedure-related complications were encountered.
  
  
  CONCLUSIONS
  This modified PAIR technique is a reliable method for percutaneous treatment of risky and symptomatic hydatid cysts.
authors.affiliation: Department of Radiology, King Fahad Hospital, Madinah, Saudi Arabia. gabalrad@yahoo.com
authors.forename: Abdelwahab M
authors.initials: AM
authors.lastname: Gabal
authors.forename: Fazal I
authors.initials: FI
authors.lastname: Khawaja
authors.forename: Ghanem A
authors.initials: GA
authors.lastname: Mohammad
mesh_terms: D000923:Anticestodal Agents / Q000008:administration & dosage / Q000627:therapeutic use; D002404:Catheterization / Q000295:instrumentation; D004443:Echinococcosis / Q000188:drug therapy / Q000628:therapy*; D004444:Echinococcosis, Hepatic / Q000188:drug therapy / Q000628:therapy; D004445:Echinococcosis, Pulmonary / Q000188:drug therapy / Q000628:therapy; D000431:Ethanol / Q000008:administration & dosage / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D015552:Injections, Intralesional; D007674:Kidney Diseases / Q000469:parasitology; D019152:Paracentesis / Q000295:instrumentation; D010532:Peritoneal Diseases / Q000469:parasitology; D011677:Punctures / Q000295:instrumentation; D015641:Radiography, Interventional; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage / Q000627:therapeutic use; D012597:Sclerosing Solutions / Q000008:administration & dosage / Q000627:therapeutic use; D013158:Splenic Diseases / Q000469:parasitology; D013396:Suction / Q000295:instrumentation; D014057:Tomography, X-Ray Computed
chemical_list: D000923:Anticestodal Agents; D012462:Saline Solution, Hypertonic; D012597:Sclerosing Solutions; D000431:Ethanol