Browsing by Author "Ocakoglu, G."
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Item Open Access Assessment of liliequist membrane by 3D-SPACE technique at 3 T(Springer, 2016) Algın, Oktay; Kılın, M.; Ozmen, E.; Ocakoglu, G.Introduction Liliequist membrane (LM) is the most important anatomic structure for the success of endoscopic third ventriculostomy (ETV). Identification of this membrane is difficult with conventional MRI techniques. The purpose of this retrospective study is to determine the impact of threedimensional sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE) sequence with variant flip-angle mode (VFAM) in the assessment of LM at 3-T MRI devices. Methods 3D-SPACE with VFAMimages were obtained in 445 patients. LM visibility and integrity were scored as 0 (good), 1 (moderate), and 2 (poor) on these images for each parts (sellar, diencephalic, and mesencephalic) and overall of the membrane. Results According to the LMoverall integrity scores, 11%(48 cases) of the patients had perforated membrane. According to subsegmental integrity scores, sellar part was completely intact in 63 % of patients, diencephalic segment was completely intact in 60 % of the patients, and mesencephalic segment was completely intact in 95 % of the patients. Visibility scores of the third ventricle inferior wall were significantly higher in the patients with intact LM (p = 0.001). There was not any statistically significant relationship between LM pattern and overall integrity (p = 0.352). LM attachment sites could be detected easier in the patients who had better visibility of third ventricle inferior wall or intact LM (p < 0.001 for both). Conclusion 3D-SPACE technique is a useful alternative for the evaluation of morphology, integrity, individual variations, topographic relationships, and visibility of LM since it has some advantages including lower SAR values, fewer artifacts, and high-resolution images.Item Open Access Assessment of third ventriculostomy patency with the 3D-SPACE technique: a preliminary multicenter research study(American Association of Neurological Surgeons, 2015) Algın, Oktay; Uçar, M.; Ozmen, E.; Borcek, A.; Ozisik, P.; Ocakoglu, G.; Tali, E.Object The goal of this study was to determine the value of the 3D sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE) technique in the evaluation of endoscopic third ventriculostomy (ETV) patency. Methods Twenty-six patients with ETV were examined using 3-T MRI units. Sagittal-plane 3D-SPACE with variant flip-angle mode, 3D T1-weighted (T1W), and 3D heavily T2-weighted (T2W) images were obtained with isotropic voxel sizes. Also, sagittal-axial plane phase-contrast cine (PC)-MR images were obtained. The following findings were evaluated: diameters of stoma and third ventricle, flow-void sign on 3D-SPACE and PC-MR images, integrity of the third ventricle on heavily T2W images, and quantitative PC-MRI parameters of the stoma. Obtained sequences were evaluated singly, in combination with one another, and all together. Results The mean area, flow, and velocity values measured at the level of stoma in patients with patent stoma were significantly higher than those measured in patients with closed stoma (p < 0.05). There was significant correlation among PC-MRI, 3D-SPACE, and 3D heavily T2W techniques regarding assessment of ETV patency (p < 0.001). The 3D-SPACE technique provided the lowest rate of ambiguous results. Conclusions The 3D-SPACE technique seems to be the most efficient one for determination of ETV patency. The authors suggest the use of 3D-SPACE as a stand-alone first-line sequence in addition to routine brain MRI protocols in assessing patients with ETV, thereby decreasing scan time and reserving the use of a combination of additional sequences such as PC-MRI and 3D heavily T2W images in suspicious or complex cases.Item Open Access Detection of cholesteatoma: high-resolution DWI using RS-EPI and parallel imaging at 3 tesla(Elsevier Masson SAS, 2017) Algin, O.; Aydın, H.; Ozmen E.; Ocakoglu, G.; Bercin, S.; Porter, D. A.; Kutluhan, A.The purpose of this study is to evaluate the impact of RS-EPI-DWI in the detection of cholesteatoma and to compare with single-shot echo-planar DWI (SS-EPI-DWI). Diffusion-weighted and apparent diffusion-coefficient (ADC) images were obtained using RS-EPI and SS-EPI techniques in 30 patients. Presence of cholesteatoma (3 point scale), amount of artefacts (4 point scale), visibility (4 point scale), and ADC values of the lesions were assessed. The results of both techniques were compared with each other and gold-standard (GS) test results. Lesion visibility and presence of artefact scores of RS-EPI-DWI group were significantly different from those of the SS-EPI group. RS-EPI-DWI images had fewer artefacts and higher visibility scores. The sensitivity, specificity, negative/positive-predictive, and overall-agreement values of RS-EPI-DWI technique were 100%, 78%, 100%, 74%, and 87%; respectively. These values for SS-EPI-DWI technique were 91%, 60%, 88%, 67%, and 75%; respectively. Also, these values were higher on axial plane than coronal plane images for ADC measurements. Based on gold-standard test findings, agreement values were good (κ = 0.74) for RS-EPI-DWI and moderate for SS-EP-DWI (κ = 0.50) techniques (P < 0.001 for both). The RS-EPI-DWI technique allows a higher spatial-resolution and this technique is less susceptible to artefacts when compared with SS-EPI technique. © 2017 Elsevier Masson SASItem Open Access Evaluation of spontaneous third ventriculostomy by three-dimensional sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE) sequence by 3 T MR imaging: preliminary results with variant flip-angle mode(Elsevier, 2013) Algın, Oktay; Turkbey, B.; Ozmen, E.; Ocakoglu, G.; Karaoglanoglu, M.; Arslan, H.Purpose This prospective study aimed to evaluate the use of three-dimensional sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE) in the diagnosis of spontaneous third ventriculostomy (STV) and to compare it with phase-contrast cine magnetic resonance imaging (PC-MRI). Methods PC-MRI and 3D-SPACE images were obtained in 15 patients with hydrocephalus for evaluation of STV as well as in 10 control cases. The presence of STV was evaluated visually by two experienced radiologists on both PC-MRI and 3D-SPACE images, and the results were statistically compared. Results There was a strong correlation between PC-MRI and SPACE scores for both readers (correlation coefficient [r] = 0.784; P = 0.001). There was also a good correlation between PC-MRI scores and consensus-based results. Interobserver reliabilities were strong for all STV scores. In addition, there was excellent correlation between 3D-SPACE scores and consensus-based results (first reader's kappa value: 0.87; second reader's kappa value: 1). Conclusion 3D-SPACE can provide morphological–physiological information for the evaluation of STV with no need for additional PC-MRI analysis or other sequences. As a non-invasive test, it can also be included among the first line of choices of MRI sequences for patients with obstructive hydrocephalus.Item Open Access Feasibility of 3-dimensional sampling perfection with application optimized contrast sequence in the evaluation of patients with hydrocephalus(Lippincott Williams and Wilkins, 2015) Kartal, M. G.; Ocakoglu, G.; Algın, OktayPurpose This study aimed to investigate the effectiveness and additive value of T2W 3-dimensional sampling perfection with application optimized contrast (3D-SPACE) with variant flip-angle mode in imaging of all types of hydrocephalus. Our secondary objective was to assess the reliability of 3D-SPACE sequence and correspondence of the results with phase-contrast magnetic resonance imaging (PC-MRI)-based data. Materials and Methods Forty-one patients with hydrocephalus have undergone 3-T MRI. T2W 3D-SPACE sequence has been obtained in addition to routine hydrocephalus protocol. Cerebrospinal fluid circulation, presence/type/etiology of hydrocephalus, obstruction level scores, and diagnostic levels of confidence were evaluated separately by 2 radiologists. In the first session, routine sequences with PC-MRI were evaluated, and in another session, only 3D-SPACE and 3-dimensional magnetization prepared rapid acquisition gradient echo sequences were evaluated. Results obtained in these sessions were compared with each other and those obtained in consensus session. Results Agreement values were very good for both 3D-SPACE and PC-MRI sequences (P < 0.001 for all). Also, the correlation of more experienced reader's 3D-SPACE-based scores and consensus-based scores was perfect (κ = 1, P < 0.001).The mean value of PC-MRI-based confidence scores were lower than those obtained in 3D-SPACE and consensus sessions. Conclusions T2W 3D-SPACE sequence provides morphologic cerebrospinal fluid flow data. It is a noninvasive technique providing extensive multiplanar reformatted images with a lower specific absorption rate. These advantages over PC-MRI make 3D-SPACE sequence a promising tool in management of patients with hydrocephalus. © 2015 Wolters Kluwer Health, Inc.