ABSTRACTpopularized (4,12). The endoscopic technique brings incontestable advantages in terms of illumination, high-resolution, close-up and wide angle view of the structures, the view around the corner, extended maneuverability and decreased trauma of the nasal structures (19), but there are also some disadvantages, caused by the different maneuverability of the surgical instruments, the two dimensional images, and the dif-█ INTRODUCTION P ituitary adenoma represents the third most common intracranial tumor (15) and the transsphenoidal approach is nowadays the standard approach for most sellar lesions. The endoscopic transsphenoidal approach is the latest innovation in this field, and since its introduction by Jankowski et al. (11) the technique has subsequently been refined and AIm: Virtual endoscopy (VE) is the navigation of a 3D model reconstructed from radiological image data. The aim of this paper is to evaluate the role and accuracy of the virtual endoscopy realized using commercially available software, OsiriX, as a method of planning of surgical interventions. mATERIAl and mEThODS: The computed tomographies of 22 patients with pituitary adenomas proposed for endoscopic approach were reconstructed using OsiriX. VE was performed prior to surgery to assess the surgical corridor and particular anatomy. We evaluated the following landmarks: inferior and middle turbinate, sphenoid ostia (SO), choanal arch (Ch), sphenoethmoidal recess (SER), sphenoid septa, sella turcica, carotid prominences and opticocarotid recesses (OCR). The intraoperative endoscopic images were reviewed and compared with the virtual images. RESUlTS:The virtual images had a good resemblance with the actual surgical images. All the structures from the nasal cavity were identified and had a perfect matching except the SO which was identified in 8 cases in VE vs. 12 intraoperative. All the structures from the sphenoid sinus were identified with perfect matching except the ipsilateral carotid prominence (14 in VE vs. 10 intraoperative) and the contralateral carotid prominence (16 in VE vs. 18 intraoperative). The VE could not show the state of the sellar floor and did not offer any information about the sellar content.CONClUSION: VE realized in OsiriX represents an affordable alternative to the specially designed systems, offering reliable data and good quality images that are useful for the preoperative planning, but some limitations are present such as inability to obtain additional information in cases where the sphenoid sinus is fully occupied by tumor or not aerated, inability to clearly differentiate between structures at the level of the sella, and impossibility to simulate working instruments.
Acta Technologica Agriculturae 1/2016Dušan Páleš et al.The most effective way for determination of curves for practical use is to use a set of control points. These control points can be accompanied by other restriction for the curve, for example boundary conditions or conditions for curve continuity (Sederberg, 2012). When a smooth curve runs only through some control points, we refer to curve approximation. The B-spline curve is one of such approximation curves and is addressed in this contribution. A special case of the B-spline curve is the Bézier curve Rédl et al., 2014). The B-spline curve is applied to a set of control points in a space, which were obtained by measurement of real vehicle movement on a slope (Rédl, 2007(Rédl, , 2008. Data were processed into the resulting trajectory (Rédl, 2012;Rédl and Kučera, 2008). Except for this, the movement of the vehicle was simulated using motion equations (Rédl, 2003;Rédl and Kročko, 2007). B-spline basis functionsBézier basis functions known as Bernstein polynomials are used in a formula as a weighting function for parametric representation of the curve (Shene, 2014). B-spline basis functions are applied similarly, although they are more complicated. They have two different properties in comparison with Bézier basis functions and these are: 1) solitary curve is divided by knots, 2) basis functions are not nonzero on the whole area. Every B-spline basis function is nonzero only on several neighbouring subintervals and thereby it is changed only locally, so the change of one control point influences only the near region around it and not the whole curve.These numbers are called knots, the set U is called the knot vector, and the half-opened interval 〈u i , u i + 1 ) is the i-th knot span. Seeing that knots u i may be equal, some knot spans may not exist, thus they are zero. If the knot u i appears p times, hence u i = u i + 1 = ... = u i + p -1 , where p >1, u i is a multiple knot of multiplicity p, written as u i (p). If u i is only a solitary knot, it is also called a simple knot. If the knots are equally spaced, i.e. (u i + 1 -u i ) = constant, for every 0 ≤ i ≤ (m -1), the knot vector or knot sequence is said uniform, otherwise it is non-uniform.Knots can be considered as division points that subdivide the interval 〈u 0 , u m 〉 into knot spans. All B-spline basis functions are supposed to have their domain on 〈u 0 , u m 〉. We will use u 0 = 0 and u m = 1.To define B-spline basis functions, we need one more parameter k, which gives the degree of these basis functions. Recursive formula is defined as follows:This definition is usually referred to as the Cox-de Boor recursion formula. If the degree is zero, i.e. k = 0, these basis functions are all step functions that follows from Eq. (1). N i, 0 (u) = 1 is only in the i-th knot span 〈u i , u i + 1 ). For example, if we have four knots u 0 = 0, u 1 = 1, u 2 = 2 and u 3 = 3, knot spans 0, 1 and 2 are 〈0, 1), 〈1, 2) and 〈2, 3), and the basis functions of degree 0 are N 0, 0 (u) = 1 on interval 〈0, 1) Acta In this co...
Asymptomatic associated intracranial lesions are more frequently diagnosed with the utilization of high-resolution imaging. The occurrence of brain tumors together with intracranial aneurysms are a very rare situation. This coexistence is still a diagnostic and therapeutic challenge as no consensus concerning imaging that may cover both type of intracranial lesion was established. We report a case of a 62 years old patient with a meningioma and aneurysm treated in one session with good outcome.
The cerebral vasospasm is still considered the most devastating complication for the patients with aneurysmal subarachnoid haemorrhage. The aim of this study was to evaluate the efficiency of intra-arterial nimodipine administration in cerebral vasospasm diminutions and outcome of the patients.
Treatment of giant thrombosed aneurysm is still a challenge for most of neurosurgeons. We present our experience of a patient with a thrombosed giant middle cerebral artery aneurysm manifesting as headache that developed over a 15-year period. Magnetic resonance (MR), computed tomographic angiography (CTA), and digital subtraction angiography (DSA) have clarified the vascular lesion and directed the therapeutic protocol. An open craniotomy with direct clipping and thrombectomy was performed successfully with an uneventful postoperative course.
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