Use of 3D space sequence in cranial magnetic resonance imaging in patients in the 0-18 years old group

Magnetic resonance imaging (MRI) is the main imaging modality in determining intracranial pathologies. Three-dimensional Sampling Perfection with Application optimized Contrasts using different flip angle The Evolution (3D SPACE) sequence uses a newly developed variable flip angle (FA), uses ultra-short echo interval (ESP), has very long echo chain interval (ETL), isotropic 3D volume (single slab / multi slab 3D) in which modifications are made. The 3D SPACE sequence is an MRI sequence with strong anatomical resolution. Using this feature, it has begun to be used routinely to determine the origin of intracranial cystic lesions such as arachnoid cyst or etiology in cases of hydrocephalus. Hydrocephalus is a pathological condition characterized by an imbalance between the production and absorption of CSF or the accumulation of CSF in the ventricles and consequently increased intracranial pressure due to blockage of the CSF circulatory paths. Intracranial arachnoid cyst was first described by Bright in 1831. Arachnoid cysts have been described as benign, homogenous, extraaxial, smooth-edged, with the same characteristics as CSF, with regular margins, often between dura and brain structures, not connected to ventricular system, intraarachnoidally located, most common congenital cystic lesions of the brain. The aim of this study was to investigate the presence of hydrocephalus, arachnoid cyst, etc. in patients with 3D SPACE sequence in the 0-18 age group. The aim of this study is to compare the etiology of intracranial pathologies associated with CSF with literature findings. For this purpose, cranial MRI of 0-18 age group was performed between January 2016 and May 2019 and clinical records of 245 patients using 3D SPACE sequence were reviewed retrospectively. Nine patients with MRI images of non-diagnostic quality due to artifacts were excluded. A total of 236 patients, 136 males and 100 females, were included in the study. Evans index was used for hydrocephalus measurements. The Evans index is found in the axial plane by dividing the largest diameter of the lateral ventricles between the frontal horns and the largest internal diameter in the largest cranium at the same level. Obstruction evaluation Foramen Monro level, Aquaductus Cerebri level, 4th Ventricular outflow level and Foramen Magnum level flow-void loss were evaluated in favor of obstruction. Axial T2W FLAIR sequences and 3D SPACE sequences on the sagittal plane were used for the diagnosis of arachnoid cysts. Axial T2 FLAIR sequence was used to differentiate it from other cystic lesions (colloidal cyst, subdural hemorrhage, etc.). Sagittal 3D SPACE sequences were used to show the relationship between CSF and cyst walls. The prevalence of hydrocephalus increases with age, presence of a previously known disease, history of CNS surgery, Chiari II malformation, Dandy Walker malformation, intracranial hemorrhage, arachnoid cyst, mega cisterna magna and previous diagnosis of hydrocephalus. The dimensions of the arachnoid cysts are not affected by the location or association with CSF. 3D SPACE sequence is a newly developed MRI sequence that provides information about CSF hydrodynamics without anatomic loss, which makes FSE-based hydrocephalus superior to conventional sequences in determining etiology due to its sensitivity to motion in CSF-derived pathologies such as arachnoid cyst. The 3D SPACE sequence may replace invasive techniques in the near future, particularly in pathologies associated with CSF hydrodynamics such as hydrocephalus Key Words: MRG, 3D SPACE, Hydrocephalus, Arachnoid cyst