METHOD FOR PREDICTION OF INTRAOPERATIVE BLOOD LOSS IN CHILDREN WITH JUVENILE ANGIOFIBROMA OF SKULL BASE AND NASOPHARYNX Russian patent published in 2024 - IPC A61B6/03 

FIELD: medicine; radiation diagnostics.

SUBSTANCE: invention can be used to predict the volume of intraoperative blood loss in children with juvenile angiofibroma of the skull base and nasopharynx. Multispiral computed tomography is performed with at least 16 sections in three orthogonal planes using a contrast preparation. Using the Inobitec DICOM-Viewer software, the tumor volume in ml is determined by the manual segmentation method, the presence or absence of the nasal tumor involvement is determined, pterygoid processes, for which axial, frontal and sagittal projections of MSCT in arterial contrasting phase are used. If the tumor tissues are within the following landmarks: distally—a projection of choanas, which is defined as a perpendicular to the base of the skull from the side of the distal visible bone edge of the nasal cavity, proximally—to the perpendicular, plotted from the middle of the distance between the proximal and distal ends of the bone base of the nasal cavity is determined from 0 to 50% of the tumor penetration into the nasal cavity and the variable [NC > 50] is assigned value of 0. If the tumor occupies more than 50% of the nasal cavity, the variable [PN > 50] is assigned value of 1. If the tumor is not located in the region of at least one of the pterygoid processes, value of 0 is assigned to the variable [PP]. If the tumor is located in the region of at least one of the pterygoid processes and/or destroys at least one of the bases of the pterygoid processes, the variable [PP] is assigned value of 1. If the tumor is not located in the projection of the pterygoid muscles, the variable [PM] is assigned value of 0. If the tumor is located in the projection of the pterygoid muscles, the variable [PM] is assigned value of 1. Probability of blood loss exceeding 1,000 ml is calculated for prediction models of blood loss. Obtained probabilities are respectively compared with critical values of probability for each model. And if at least one model gives a probability greater than or equal to a critical value, a blood loss of 1,000 ml and more is predicted.

EFFECT: method enables increasing the accuracy and objectivity of the non-invasive assessment of the risk of complications in the form of significant haemorrhage during the surgical treatment in children with juvenile angiofibroma of the skull base and nasopharynx by assessing the position of the tumor tissues.

1 cl, 5 ex, 2 tbl