RESUMEN

A case is presented of a 59-year-old male patient with a 5-year history of sarcoidosis. In the last half a year, deterioration of his intellectual abilities was noticed. Psychological testing detected a mild cognitive disorder. Laboratory diagnostics found a decreased level of testosterone and magnetic resonance imaging showed pituitary stalk neurosarcoidosis without any other pathomorphological substrate of cognitive impairment. This case indicates that neurosarcoidosis should be considered as a possible cause of mild cognitive disorder and, consequently, included in the International Classification of Mental and Behavioural Disorders.

Asunto(s)

RESUMEN

OFTEN AND IN VARIOUS CONNOTATIONS ONE CAN HEAR OR READ THE FOLLOWING SYNTAGMA: "Let's leave the past in the past - and turn to the future". Even more frequent and numerous are opposite opinions, e.g. "There is no future without past", "Future is built on past" or "Remembering our past - reaching for our future", and many more.

RESUMEN

There are quantifiable abnormalities in water diffusion properties of the white matter in thalamic and prefrontal areas in patients with idiopathic dystonia (ID). However, it is unclear which pathways are disrupted in these patients. Using probabilistic tractography of high resolution DTI, we reconstructed thalamic prefrontal pathways in seven patients with ID and seven matched controls. Resulting fibers were registered onto the stereotaxic space and submitted to a voxel-wise statistical analysis comparing patients and controls. Patients with ID exhibited less thalamic prefrontal connections, particularly involving fibers traveling from the thalamus to the middle frontal gyrus. These results corroborate neurophysiologic findings of reduced and asynchronous thalamic prefrontal input, and emphasize the structural correlates of the pathophysiology of ID.

Asunto(s)

RESUMEN

We investigated whether structural white matter abnormalities, in the form of disruption of axonal coherence and integrity as measured with diffusion tensor imaging (DTI), constitute an underlying pathological mechanism of idiopathic dystonia (ID), independent of genotype status. We studied seven subjects with ID: all had cervical dystonia as their main symptom (one patient also had spasmodic dysphonia and two patients had concurrent generalized dystonia, both DYT1-negative). We compared DTI MR images of patients with 10 controls, evaluating differences in mean diffusivity (MD) and fractional anisotropy (FA). ID was associated with increased FA values in the thalamus and adjacent white matter, and in the white matter underlying the middle frontal gyrus. ID was also associated with increase in MD in adjacent white matter to the pallidum and putamen bilaterally, left caudate, and in subcortical hemispheric regions, including the postcentral gyrus. Abnormal FA and MD in patients with ID indicate that abnormal axonal coherence and integrity contribute to the pathophysiology of dystonia. These findings suggest that ID is not only a functional disorder, but also associated with structural brain changes. Impaired connectivity and disrupted flow of information may contribute to the impairment of motor planning and regulation in dystonia.

Asunto(s)

RESUMEN

INTRODUCTION: Our goal was to evaluate whether the T1 shortening effect caused by contrast leakage into brain tumors, a well-known confounding effect in the quantification of relative cerebral blood volume (rCBV) measurements, may be corrected by the administration of a predose of gadolinium-DTPA. METHODS: As part of their presurgical imaging protocol, 25 patients with primary brain tumors underwent two consecutive dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion MR studies. Intratumoral rCBV measurements and normalized rCBV values obtained during the first-pass and second-bolus studies were compared (Wilcoxon signed-ranks test). The frequency of relatively increased rCBV ratios on the second-bolus study was compared between enhancing and non-enhancing neoplasms (Fisher's exact test). Postprocessing perfusion studies were evaluated for image quality on a scale of 0-3 (Wilcoxon signed-ranks test). Four studies were excluded due to unacceptable image quality. RESULTS: Mean normalized rCBVs were 9.04 (SD 4.64) for the first-pass and 7.99 (SD 3.84) for the second-bolus study. There was no statistically significant difference between the two perfusion studies in either intratumoral rCBV (P=0.237) or rCBV ratio (P=0.181). Five enhancing and four non-enhancing tumors showed a relative increase in rCBV ratio on the second-bolus study, without a significant difference between the groups. Image quality was not significantly different between perfusion studies. CONCLUSION: Our results did not demonstrate a significant difference between first-pass and second-bolus rCBV measurements in DSC perfusion MR imaging. The administration of a predose of gadolinium-DTPA does not appear to be an efficient way of compensating for the underestimation of intratumoral rCBV values due to the T1 shortening effect.

Asunto(s)

RESUMEN

We compared magnetic resonance imaging (MRI), magnetic resonance angiography, and transcranial Doppler ultrasonography as predictors of specific neurocognitive functions in children with sickle cell disease. Participants were 27 children with sickle cell anemia (hemoglobin SS) who were participants in the Stroke Prevention Trial in Sickle Cell Anemia (STOP) and had no documented history of stroke. Children's MRIs were classified as normal or silent infarct, and their magnetic resonance angiograms were classified as normal or abnormal. The highest time-averaged mean flow velocity on transcranial Doppler ultrasonographic examination of the major cerebral arteries was analyzed. Age and hematocrit also were analyzed as predictor variables. The battery of neurocognitive tests included measures of intellectual functioning, academic achievement, attention, memory, visual-motor integration, and executive functions. MRI, magnetic resonance angiography, transcranial Doppler ultrasonography, age, and hematocrit were analyzed as predictors of participants' performance on the various measures of neurocognitive functioning. Age and hematocrit were robust predictors of a number of global and specific neurocognitive functions. When age and hematocrit were controlled, transcranial Doppler ultrasonography was a significantly unique predictor of verbal memory. We found an association between low hemoglobin and neurocognitive impairment. We also found that abnormalities on transcranial Doppler ultrasonography can herald subtle neurocognitive deficits. (J Child Neurol 2006;21:37-44).

Asunto(s)

RESUMEN

BACKGROUND AND PURPOSE: On the basis of limited available data, brain MR imaging abnormalities in kidney transplant recipients (KTRs) have been predominantly attributed to calcineurin inhibitors (CIs), characteristically presenting as posterior reversible encephalopathy syndrome (PRES). The goal of this study was to evaluate whether CIs play an important role in the incidence, nature, and location of MR imaging brain lesions in adult KTRs by comparing them with dialysis-dependent patients. METHODS: We retrospectively analyzed 98 brain MR imaging examinations in 77 consecutive KTRs presenting with neurologic symptoms from 1990 to 2003. The data were separated into 3 groups according to duration after transplantation of MR imaging: group 1, 0-3 months; group 2, 3-12 months; and group 3, >12 months. Twenty-six MR imaging examinations from 24 additional dialysis-dependent adults were used as controls and comprised group 0. RESULTS: Acute changes (infarcts, infections, PRES) comprised 24% and 19% of lesions in KTRs and group 0 patients, respectively, with infarcts being the most common in all groups. Chronic lesions were responsible for 76% of changes in KTR and 81% in group 0 and were predominantly vascular in etiology. No statistically significant differences in incidence of PRES or other acute changes were found between dialysis-dependent patients and either individual KTR groups or all KTR patients combined. The deep gray matter lesions were more common in KTR, whereas frontal white matter was more frequently affected in patients on dialysis. CONCLUSION: Our study does not support suggestion that MR imaging brain abnormalities in KTR are predominantly due to direct CI toxicity.

Asunto(s)

Asunto(s)

RESUMEN

One of the main objectives of our 3-dimensional (3D) computer-assisted functional endoscopic sinus surgery was to design a computer-assisted 3D approach to the presurgical planning, intraoperative guidance, and postoperative analysis of the anatomic regions of the nose and paranasal sinuses. Such an extremely powerful approach should allow better insight into the operating field, thereby significantly increasing the safety of the procedure. The last step to implementing the technology in the operating room was to connect the computer workstations and video equipment to remote locations by using a high-speed, wide-bandwidth computer network. During patient preparation, the surgeon in the operating room consulted remote experienced and skillful surgeons by viewing CT images and 3D models on computer workstations. The surgeon and consultants used software for CT image previews and 3D model manipulations on top of collaboration tools to define the pathosis, produce an optimal path to the pathosis, and decide how to perform the real surgical procedure. With tele-flythrough or tele-virtual endoscopy rendered through the use of 3D models, both surgeons can preview all the characteristics of the region (ie, anatomy, pathosis) and so predict and determine the next steps of the operation. This ensures greater safety thanks to the operation guidance and reduces the possibility of intraoperative error. The duration of the teleconsultation is thus shortened, which may prove the greatest benefit of tele-3D computer-assisted surgery. If this method were used, clinical institutions would spend less money for telesurgical consultation.

Asunto(s)

RESUMEN

Foreign bodies in paranasal sinuses are found quite infrequently. They are usually detected after various types of head trauma and most commonly occur as a consequence of improper handling of firearms or explosives. In countries at war, eg, during the war in Croatia, adults and children were almost equally exposed to these injuries. The diagnosis should be based on results from precise computer tomography (CT) scanning in axial and coronal sections, and, using these data, tissues of different densities at these anatomical locations can be differentiated. The possibility of exact preoperative, noninvasive visualization of the spatial relationships of anatomic and pathologic structures with 3-dimensional (3D) computer-assisted diagnosis and intraoperative navigational techniques allows the surgeon to achieve a considerable advantage in the preoperative examination of the patient and to reduce the risk of intraoperative complications, all by the use of virtual surgery (VS) or virtual diagnosis. The expected contribution of the mentioned computer-assisted surgical technique manifests itself in defining the most appropriate mode of CT scanning of the head to design the 3D operating field model, and the possibility of active and dynamic 3D visualization of the desired anatomical regions is realized. 3D reconstruction of anatomic units becomes a routine preoperative procedure, providing a highly useful and informative visualization of the regions of interest, and, thus, advancing the definition of geometric information on anatomical contours of the 3D model by the transfer of so-called image pixel to contour pixel.

Asunto(s)

RESUMEN

The main goal of our dynamic 3D computer-assisted reconstruction of a metallic retrobulbar foreign body following orbital injury with ethmoid bone involvement was to use 3D-information obtained from standard computed tomography (CT) data to explore and evaluate the nasal cavity, ethmoidal sinuses, retrobulbar region, and the foreign body itself by simulated dynamic computed visualization of the human head. A foreign body, 10 x 30 mm in size, partially protruded into the posterior ethmoidal cells and partially into the orbit, causing dislocation and compression of the medial rectus muscle and inferior rectus muscle. The other muscles and the optic nerve were intact. Various steps were taken to further the ultimate diagnosis and surgery. Thin CT sections of the nasal cavity, orbit and paranasal sinuses were made on a conventional CT device at a regional medical center, CT scans were transmitted via a computer network to different locations, and special views very similar to those seen on standard endoscopy were created. Special software for 3D modeling, specially designed and modified for 3D C-FESS purposes, was used, as well as a 3D-digitizer connected to the computer and multimedia navigation through the computer during 3D C-FESS. Our approach achieves the visualization of very delicate anatomical structures within the orbit in unconventional (non-standard) sections and angles of viewing, which cannot be obtained by standard endoscopy or 2D CT scanning. Finally, virtual endoscopy (VE) or a 'computed journey' through the anatomical spaces of the paranasal sinuses and orbit substantially improves the 3D C-FESS procedure by simulating the surgical procedure prior to real surgery.