The Anatomy of Circulus Arteriosus Cerebri (Circle of Willis): A Study in Turkish Population.

AIM: The function of the circle of Willis, an arterial polygon, is to protect the brain from ischemia. The aim of this study is to define the structural characteristics of the circle of Willis within the Turkish adult population, along with variations and arteries involved in the measurement of diameters and lengths on cadavers. MATERIAL AND METHODS: The circle of Willis was evaluated in 100 fresh adult cadavers. Structures of the circle of Willis were evaluated as being typical or atypical images and according to the diameter of AComP. All arteries forming the circle's length and diameters were measured. RESULTS: All arteries forming the circle of Willis as 91% were anatomically observed. The typical structure in which hypoplasia arteries is not involved was obtained as 8%. The atypical circle of Willis with aplasia was seen as 9%. 87% of adult, 9% fetal, and 4% transitional configuration in the samples were detected. The variations of the circle of Willis were more common in the posterior portion. Hypoplasia was found to be the most common variation and noted as a maximum in AComP (85%). Aplasia was noted as the second most common variation after hypoplasia and again the most common in AComP (5%). CONCLUSION: Advances in radiological methods which provide images of cerebral vessels and the development of cerebrovascular surgery have increased the importance of the circle of Willis in neurosurgery and neurology. The structure of the circle of Willis is of great importance in occlusive cerebrovascular diseases and cerebrovascular surgery.

Assessment of the Circle of Willis with Cranial Tomography Angiography.

BACKGROUND: The circle of Willis is a major collateral pathway important in ischemic conditions. The aim of our study was to assess the structural characteristics of the circle of Willis within the Turkish adult population, along with variations and arteries involved in the measurement of diameters and lengths on cranial computed tomography angiography (CTA). MATERIAL AND METHODS: One hundred adult patients who underwent CTA images were evaluated retrospectively. RESULTS: Results of the study revealed 82% adult, 17% fetal, and 1% transitional configurations. A complete polygonal structure was observed in 28% of cases. Variations of the circle of Willis were more common in the posterior portion. Hypoplasia was found to be the most common variation and was observed as a maximum in the posterior communicating artery (AComP). CONCLUSIONS: The patency and size of arteries in the circle of Willis are important in occlusive cerebrovascular diseases and cerebrovascular surgery. Although CTA is an easily accessible non-invasive clinical method for demonstrating the vascular structure, CTA should be evaluated taking into account image resolution quality and difficulties in the identification of small vessels.

Neurologic complications of renal transplant.

OBJECTIVES: Neurologic problems have a major effect on the survival and quality of life in renal transplant recipients. This study sought to review the incidence and character of neurologic complications after renal transplant. MATERIALS AND METHODS: Medical records of 319 renal transplant recipients admitted to the Transplant Outpatient Clinic were reviewed retrospectively for neurologic complications. RESULTS: Of the 319 transplant recipient patients reviewed, 124 patients (39%) were women and 193 patients (61%) were men. The mean patient age was 41 ± 11 years, and the transplanted kidney was received from deceased donors in 161 patients (51%) and living donors in 158 patients (49%). There were 50 patients (16%) who had neurologic complications, most commonly herpes zoster infection associated with immunosuppressive medication. Only 1 patient, who had glioblastoma multiforme, died. Treatment included corticosteroids in 296 patients (93%) and calcineurin inhibitors (including tacrolimus) in 111 patients (35%). CONCLUSIONS: Neurologic complications are common after renal transplant. Most complications are associated with immunosuppressive medications.