title: Diagnosis of acute cortical necrosis in renal transplantation by contrast-enhanced ultrasound: a preliminary experience.
abstract: OBJECTIVE
  To evaluate the use of contrast-enhanced ultrasound (CEUS) for diagnosis of cortical necrosis in renal allografts.
  
  
  METHODS
  We reviewed the medical records and imaging studies of five patients who underwent emergency transplantectomy and a histological diagnosis of cortical necrosis in the period between May 2009 and May 2011. US examinations included initially B-mode and color Doppler and then contrast-enhanced ultrasound with low mechanical index after injection of 2.4 ml of a second generation echo-signal enhancer. Renal transplant vascularization was evaluated during a period of 4 minutes including arterial, corticomedullary and nephrographic phases. Radiologic-pathologic correlation was obtained after transplantectomy in all cases.
  
  
  RESULTS
  Five patients with an age range between 30 and 48 years. Post-transplant color Doppler ultrasound showed decreased renal parenchymal vascularization and difficulty to find the spectral waveforms with resistive indexes greater than 0.7 in 4 of 5 patients. CEUS showed enhancement of the main arteries, followed by the enhancement of medullary pyramids, but with an unenhanced peripheral cortical continuous band viewed in all phases, a similar finding to the peripheral rim sign, pathognomonic of cortical necrosis on CT or MRI. The pathologic assessment showed violet kidneys macroscopically with hemorrhagic foci in the outer cortical that drew a well-defined band, findings agreed with CEUS findings.
  
  
  CONCLUSIONS
  CEUS can show the typical peripheral rim sign in cases of cortical necrosis allowing a reliable and fast diagnosis of this condition and it could obviate further imaging studies or biopsy, allowing an earlier decision of nephrectomy.
authors.affiliation: Radiology, Hospital Universitario Doctor Peset, Valencia, Spain. lalitadoc@gmail.com
authors.forename: C P
authors.initials: CP
authors.lastname: Fernandez
authors.forename: T
authors.initials: T
authors.lastname: Ripolles
authors.forename: M J
authors.initials: MJ
authors.lastname: Martinez
authors.forename: J
authors.initials: J
authors.lastname: Blay
authors.forename: L
authors.initials: L
authors.lastname: Pallardó
authors.forename: E
authors.initials: E
authors.lastname: Gavela
mesh_terms: D000208:Acute Disease; D000328:Adult; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007668:Kidney / Q000098:blood supply / Q000473:pathology; D007673:Kidney Cortex Necrosis / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D010743:Phospholipids; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D012039:Regional Blood Flow / Q000502:physiology; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000473:pathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013459:Sulfur Hexafluoride; D018615:Ultrasonography, Doppler, Color
chemical_list: D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride