[Clinical application analysis of a method for locating scalp projection of intracranial lesions based on...

Objective: To explore the feasibility of a method based on neuroimaging and surface markers for locating scalp projection of intracranial lesions. Methods: The clinical data of 46 patients who were used 'double-circle method' for locating scalp projection of intracranial lesions at Department of Neurosurgery,the First Affiliated Hospital of Xiamen University from January to June 2021 were retrospective analyzed. All patients with 2 electrodes(artificial fiducials) randomly attached to scalp had been examed thin-layer brain CT. The distances from the center of each fiducial to the root of the nose and tragus were measured through the images. A compass was used to draw two arcs with the root of nose and the tragus as the center and the pre-measured distance as the radius on patient's scalp. Then two arcs' intersection on the scalp was the fiducial. The method was named 'double-circle method'. Two neurosurgeons were arranged to perform fiducial identification with double-circle method, and record the error between the result and the actual fiducial point.Independent sample t test was used for data comparison, and Kappa test was used to analysis the inter-group consistency. Results: Ninety-two fiducial points of 46 patients were collected. Time consuming of doctor A was (8.1±2.3) minutes(range:5 to 15 minutes)and doctor B was (8.9±3.5) minutes(range:4 to 17 minutes).The positioning error from the doctor A was (4.4±2.4)mm(range:0 to 12 mm) and doctor B was(4.2±2.6) mm(range:0 to 14 mm)(t=-0.575,P=0.567),the difference was not statistically significant. The Kappa value of the consistency test of error between two doctors was 0.517(P=0.001).The consistency was moderate.Eight patients used 'double-circle method' and neuronavigation for locating scalp projection of intracranial lesions at the same time. The diameter of the lesions was (3.8±0.9)cm (range: 2.6 to 5.1 cm), and the positioning error of the 'double-circle method' and navigation was (4.0±1.9) mm(range: 1 to 6 mm), and all patients were confirmed to be accurately located during surgery. Conclusion: 'Double-circle method' is a simple,convenient and accurate way in locating intracranial lesions and has certain clinical significance.