title: Minimal invasive biopsy of intraconal expansion by PET/CT/MRI image-guided navigation: a new method.
abstract: Intraorbital tumours are often undetected for a long period and may lead to compression of the optic nerve and loss of vision. Although CT, MRI's and ultrasound can help in determining the probable diagnosis, most orbital tumours are only diagnosed by surgical biopsy. In intraconal lesions this may prove especially difficult as the expansions are situated next to sensitive anatomical structures (eye bulb, optic nerve). In search of a minimally invasive access to the intraconal region, we describe a method of a three-dimensional, image-guided biopsy of orbital tumours using a combined technique of hardware fusion between (18)F-FDG Positron Emission Tomography ((18)F-FDG PET), magnetic resonance imaging (MRI) and Computed Tomography (CT).
  
  
  METHODS
  We present 6 patients with a total of 7 intraorbital lesions, all of them suffering from diplopia and/or exophthalmos. There were 3 female and 3 male patients. The patients age ranged from 20 to 75 years. One of the patients showed beginning loss of vision. Another of the patients had lesions in both orbits. The decision to obtain image-guided needle biopsies for treatment planning was discussed and decided at an interdisciplinary board comprising other sub-specialities (ophthalmology, neurosurgery, maxillofacial surgery, ENT, plastic surgery). All patients underwent 3D imaging preoperatively ((18)F-FDG PET/CT or (18)F-FDG PET/CT plus MRI). Data was transferred to 3D navigation system. Access to the lesions was planned preoperatively on a workstation monitor. Biopsy-needles were then calibrated intraoperatively and all patients underwent three-dimensional image-guided needle biopsies under general anaesthesia.
  
  
  RESULTS
  7 biopsies were performed. The histologic subtype was idiopathic orbital inflammation in 2 lesions, lymphoma in 2, Merkel cell carcinoma in 1, hamartoma in 1 and 1 malignant melanoma. The different pathologies were subsequently treated in consideration of the actual state of the art. In cases where surgical removal of the lesion was performed the histological diagnosis was confirmed in all cases.
  
  
  CONCLUSIONS
  There is a wide range of possible treatment modalities for orbital tumours depending on the nature of the lesion. Histological diagnosis is mandatory to select the proper management and operation. The presented method allows minimal-invasive biopsy even in deep intraconal lesions, enabling the surgeon to spare critical anatomical structures. Vascular lesions such as cavernous haemangioma, tumour of the lacrimal gland or dermoid cysts present a contraindication and have to be excluded.
authors.affiliation: Department of Oromaxillofacial Surgery (Head: Univ. Prof. Dr. Kärcher Hans), Medical University Graz, Auenbruggerplatz 5, 8036 Graz, Austria. Electronic address: knut.reinbacher@medunigraz.at.
authors.forename: Knut E
authors.initials: KE
authors.lastname: Reinbacher
authors.affiliation: Department of Oromaxillofacial Surgery (Head: Univ. Prof. Dr. Kärcher Hans), Medical University Graz, Auenbruggerplatz 5, 8036 Graz, Austria.
authors.forename: Mauro
authors.initials: M
authors.lastname: Pau
authors.affiliation: Department of Oromaxillofacial Surgery (Head: Univ. Prof. Dr. Kärcher Hans), Medical University Graz, Auenbruggerplatz 5, 8036 Graz, Austria.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Wallner
authors.affiliation: Department of Oromaxillofacial Surgery (Head: Univ. Prof. Dr. Kärcher Hans), Medical University Graz, Auenbruggerplatz 5, 8036 Graz, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Zemann
authors.affiliation: Clinic for Ophthalmology, Medical University Graz, Austria.
authors.forename: Angelika
authors.initials: A
authors.lastname: Klein
authors.affiliation: Clinic for Radiology (Head: Reingard M. Aigner, PHD, MD), Medical University Graz, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Gstettner
authors.affiliation: Clinic for Radiology (Head: Reingard M. Aigner, PHD, MD), Medical University Graz, Austria.
authors.forename: Reingard M
authors.initials: RM
authors.lastname: Aigner
authors.affiliation: Department of Oromaxillofacial Surgery (Head: Univ. Prof. Dr. Kärcher Hans), Medical University Graz, Auenbruggerplatz 5, 8036 Graz, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Feichtinger
mesh_terms: D000328:Adult; D000368:Aged; D015266:Carcinoma, Merkel Cell / Q000175:diagnosis / Q000473:pathology; D004172:Diplopia / Q000175:diagnosis; D005094:Exophthalmos / Q000175:diagnosis; D005260:Female; D019788:Fluorodeoxyglucose F18; D006222:Hamartoma / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D061705:Image-Guided Biopsy / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D008223:Lymphoma / Q000175:diagnosis / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000473:pathology; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D064847:Multimodal Imaging / Q000379:methods*; D009916:Orbital Diseases / Q000175:diagnosis / Q000473:pathology; D009918:Orbital Neoplasms / Q000175:diagnosis* / Q000473:pathology; D010347:Patient Care Planning; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Image-guided surgery; Intraconal lesion; Minimal invasive biopsy; Orbital