ABSTRACT
OBJECTIVE: The aim of the present work was to establish a method for orbital volume calculation based on MR scanning data for the sake of better radiation hygiene. MATERIALS AND METHODS: The orbital volumes of 35 ophthalmologically healthy children were calculated on the basis of MRI scans. After data transfer to a separate workstation, volumetric analysis was carried out by two independent radiologists using semi-automated software. The accuracy of the calculated values was compared with orbital volumes measured by anatomic preparations and given in studies by various authors. RESULTS: Volume calculation was possible in all patients using MRI data. There is an acceptable agreement with the presented anatomic facts and the measured values of Bentheley. In the Wilcoxon test there was not a big difference between the courses of the values (p = 0.507). CONCLUSION: Even though we can obtain a better image of the bizarre structure of the bony orbits with CT, MR-based volumetry of the orbit is a reliable method and is not burdened by radiation exposure. It can thus be an important condition for the planning and the controlling of modern therapeutic concepts in treating anophthalmos and microphthalmos.
Subject(s)
Anthropometry/methods , Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging/methods , Orbit/anatomy & histology , Aging/physiology , Anophthalmos/diagnosis , Anophthalmos/therapy , Child , Child, Preschool , Female , Humans , Infant , Male , Orbit/growth & development , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
INTRODUCTION: The purpose of this study is to report orbital volume measurement results in patients with congenital clinical anophthalmia before and after therapy and to compare them with normal values. PATIENTS AND METHOD: Normal values were obtained from 35 healthy children (22 boys, 13 girls; aged 3 month to 7 years) in whom MRI was done for non-ophthalmological reasons. 18 patients with congenital anophthalmos could be included, 9 with bilateral, 8 with unilateral disease and 1 microphthalmos. 6 of them had MRI follow-up (more than one examination). RESULTS: Orbital volume at birth is 7 ml and it increases with age: Orbital volume = 7.701 x age (month) (0.2484) ml. It is around 14.2 ml at the age 1 year, 17 ml with 2 years and reaches 23 ml with 7 years. In unilateral clinical anophthalmos orbital volume is 35 to 58 % compared with the healthy side and 31 to 65 % compared with the normal values. In bilateral cases the volume is 43 to 70 % of the normal value. During treatment it develops in parallel to the normal values. CONCLUSIONS: The normal values measured by our group are in accordance with the only published study by Bentley . MRI orbital volumetry is a reliable method without using radiation. It allows us to quantify the bony asymmetry and is suitable for therapy control when using orbital expanders. The congenital missing eye might be the most important reason why the orbit does not develop in the normal way to a normal size. Self-inflating high, hydrophilic hydrogel expanders do not seem to be able to compensate this, in spite of the fact that they work very well to prepare the socket for a prosthesis.
Subject(s)
Anophthalmos/diagnosis , Anophthalmos/surgery , Hydrogels , Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging/methods , Orbit/pathology , Tissue Expansion/methods , Aging/pathology , Anthropometry/methods , Child , Child, Preschool , Female , Humans , Image Interpretation, Computer-Assisted/methods , Infant , Male , Ophthalmologic Surgical Procedures/methods , Orbit/growth & development , Reproducibility of Results , Sensitivity and Specificity , Treatment OutcomeABSTRACT
PURPOSE: To determine the value of MRI in the preoperative evaluation of chronic paranasal sinusitis and to compare the results with CT and intraoperative findings. METHOD/MATERIALS: 42 patients with clinical signs of chronic paranasal sinusitis underwent MRI after CT evaluation on one day, with subsequent functional endoscopic sinus surgery on the next day. Coronary CT was obtained with 5-mm slices and table-feed in the prone position, while MRI was performed in the supine position with coronary T2-TSE + pd and coronary and transverse HASTE, each with 5-mm slice thickness. Aquisition time in MRI was less than 8 minutes. Two radiologists reviewed the CT and MRI scans for signs of sinusitis and detection of anatomical landmarks. The results were correlated with the intraoperative findings. RESULTS: MRI offered no artifacts of dental work and showed more often high quality pictures than CT. CT and MRI demonstrated a good correlation in the detection of mucosal pathologies (kappa = 0.46-0.87) and anatomic variants (kappa = 0.55-0.86). All important anatomical structures could be evaluated sufficiently with MRI for preoperative management. Both diagnostic tools showed an unsatisfactory correlation with intraoperative findings in the ethmoidal complex and maxillary sinus (tau = -0.08-0.3). CONCLUSIONS: MRI is a fast and reliable alternative to preoperative CT in examining paranasal sinuses and offers a good visualization of mucosal changes. CT and MRI both give an unreliable representation of the ethmoidal complex.
