title: Needle-tract implantation in hepatocellular carcinoma: frequency and CT findings after biopsy with a 19.5-gauge automated biopsy gun.
abstract: BACKGROUND
  Needle-tract implantation is an important complication of cutting biopsy of hepatocellular carcinoma (HCC). This study was performed to evaluate the frequency of needle-tract implantation after ultrasound (US)-guided percutaneous biopsy of HCC and to describe triple-phase helical computed tomographic (CT) findings of implanted nodules.
  
  
  METHODS
  Between April 1994 and December 1997, 205 patients underwent US-guided percutaneous biopsy for HCC. Review of medical records and the pathology database disclosed seven patients who were found to have needle-tract implantation of HCC. Among these patients, five underwent triple-phase helical CT examination. We analyzed the frequency of needle-tract implantation and triple-phase helical CT findings of implanted nodules, with particular attention to the morphology and enhancement pattern.
  
  
  RESULTS
  Seven of 205 patients (3.4%) had tumor implantation along the needle tract at histologic examination after surgical resection. Eight implanted nodules in five patients were found on triple-phase helical CT images (one nodule in three patients, two nodules in one patient, and three nodules in one patient). All implanted nodules has well-circumscribed margins and were ovoid or lobulated in contour. On triple-phase helical CT, six (75%) implanted nodules were isodense compared with abdominal wall muscle on all triple-phase CTs, and two (25%) nodules were hyperdense on hepatic arterial and portal venous phases and isodense on equilibrium phase.
  
  
  CONCLUSIONS
  The frequency of needle-tract implantation of HCC after percutaneous needle biopsy was higher than reported previously, and careful attention should be paid during interpretation of CT images in patients with a history of previous percutaneous biopsy.
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: S H
authors.initials: SH
authors.lastname: Kim
authors.forename: H K
authors.initials: HK
authors.lastname: Lim
authors.forename: W J
authors.initials: WJ
authors.lastname: Lee
authors.forename: J M
authors.initials: JM
authors.lastname: Cho
authors.forename: H J
authors.initials: HJ
authors.lastname: Jang
mesh_terms: D000009:Abdominal Muscles; D000328:Adult; D000368:Aged; D001707:Biopsy, Needle / Q000009:adverse effects* / Q000295:instrumentation; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D019042:Muscle Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary; D009366:Neoplasm Seeding; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary; D013909:Thorax; D014057:Tomography, X-Ray Computed