Josef Vymazal

Článek podává přehled o možnostech diagnostiky a základní diferenciální diagnostiky extrapyramidových onemocnění pomocí magnetické rezonance. Soustřeďuje se na rozlišení mezi Parkinsonovou nemocí, atypickými parkinsonskými syndromy, dále popisuje charakteristický MR obraz Huntingtonovy choroby a Wilsonovy nemoci. V rámci širší diferenciální diagnostiky je zmíněn i chronický subdurální hematom a

Purpose: To characterize the relationship between superparamagnetic ferritin‐bound iron and diffusion tensor scalars in vitro, and validate the results in vivo.Materials and Methods: The in vitro model consisted of a series of 40‐mL 1.1% agarose gels doped with ferritin covering and exceeding those concentrations normally found within healthy human gray matter. Additionally, regions of interest were placed in the caudate, putamen, and globus pallidus of 29 healthy volunteer subjects 19–80 years of age. Carr‐Purcell‐Meiboom‐Gill sequence (CPMG) and diffusion tensor imaging (DTI) data were collected at 1.5 Tesla (T) and 3T in vitro, and at 1.5T in vivo.Results: In vitro, linear relationships were observed between ferritin‐bound iron concentration, R₂ (1/T₂) and 1/SNR. Eigenvalue repulsion with increasing R₂ (decreasing SNR) was reflected in an artifactual increase of fractional anisotropy. In vivo, similar relationships were observed, with mean diffusivity also decreasing linearly with increasing R₂. Lambda 3 showed the strongest correlation with R₂ both in vitro and in vivo.Conclusion: The observation that DTI metrics correlate with ferritin‐bound iron is an important consideration in the design and interpretation of studies exploring the diffusion characteristics of gray matter regions, especially in studies focused on adolescence as well as diseases associated with altered brain‐iron load such as pantothenate kinase‐associated neurodegeneration, Huntington disease and multiple system atrophy. J. Magn. Reson. Imaging 2013;38:1103–1110.

Glioblastoma multiforme (GBM) is the most common and malignant primary intracranial tumor, and has a median survival of only 10 to 14 months with only 3 to 5% of patients surviving more than three years. Recurrence (RGBM) is nearly universal, and further decreases the median survival to only five to seven months with optimal therapy. Tumor-treating fields (TTField) therapy is a novel treatment technique that has recently received CE and FDA approval for the treatment of RGBM, and is based on the principle that low intensity, intermediate frequency electric fields (100 to 300 kHz) may induce apoptosis in specific cell types. Our center was the first to apply TTField treatment to histologically proven GBM in a small pilot study of 20 individuals in 2004 and 2005, and four of those original 20 patients are still alive today. We report two cases of GBM and two cases of RGBM treated by TTField therapy, all in good health and no longer receiving any treatment more than seven years after initiating TTField therapy, with no clinical or radiological evidence of recurrence.

Cerebrovascular disease represents a major source of global mortality and morbidity. Imaging examinations play a critical role in the management of stroke patients, from establishing the initial diagnosis to determining and guiding further treatment. In this article, current CT and MRI methods employed in the management of stroke patients are reviewed, with an emphasis on ischemic stroke. The advantages and disadvantages of these techniques are discussed, a number of cases emphasizing key points are presented, and a comparison between modern CT and MRI techniques is outlined. The major drawback of CT is the high radiation dose, while in MRI it is the more complicated and time-consuming aspect of the examination. • Cerebrovascular disease represents a major source of global mortality and morbidity • Imaging examinations play a critical role in the management of stroke patients • The penumbra may be seen with both CT and MRI; however, this concept may be overly simplistic • The major drawback of CT is the high radiation dose, while MRI is a more complicated examination

To evaluate the potential of quantitative MR techniques [voxel-based morphometry (VBM), T2-relaxometry, mean diffusivity (MD), fractional anisotropy (FA)] in the diagnostics of amyotrophic lateral sclerosis (ALS). Thirty-three ALS patients and thirty age- and sex-matched healthy volunteers were included in the cross-sectional study. T1WI, T2WI and T2 relaxometry sequences were performed at 1.5T. DWI was performed in a subgroup of 12 patients. Disease severity was estimated with the ALS Functional Rating Scale (ALS-FRS). We detected decreased T2 relaxation rate (R2) in the frontal white matter (FWM) (left and right P < 0.005) and caudate nucleus (left P < 0.005) in ALS patients. R2 in the FWM correlated with age in patients and controls. A correlation (P < 0.01, cluster-level corrected) between atrophy in the corona radiata and the limb ALS-FRS subset was found, as well as a difference between patients and controls in this area. No correlation between FA/MD and ALS-FRS was observed in the T2 hyperintense region of the posterior limb of the internal capsule (PLIC), or in the site of atrophy detected by VBM. No R2 or PD changes in the PLIC were detected. TBSS revealed decreased FA in the corona radiata and callosal body. Decreased R2 in the left caudate and bilateral FWM may help in the diagnostic process and disqualifies these regions as internal controls in ALS studies. The PLIC is not a reliable diagnostic marker of ALS.

Temporal lobe epilepsy is the most common type of focal epilepsy diagnosed in adult patients. According to the location of seizure generation it is classified as mesial temporal lobe epilepsy and neocortical lateral lobe epilepsy. Diagnosis of temporal lobe epilepsy can be proved by the combination of the clinical manifestation of partial complex seizures, scalp-video EEG monitoring, results of magnetic resonance imaging (MRI) and imaging of interictal fluoro-deoxy-glucose positron emission tomography. Mesial temporal sclerosis is the most common finding on MRI. Temporal lobe epilepsy is the most surgically amenable diagnosis and results of surgery treatments are clearly superior to the prolonged medical therapy; surgical treatment of the mesial temporal epilepsy with mesial temporal sclerosis has the best clinical results. Except for standard microsurgical approaches such as anterior temporal resection and selective amygdalo-hippocampectomy, stereotactic thermocoagulation amygdalo-hippocampectomy is provided in our epilepsy centre. This alternative approach has comparable clinical outcome to the standard surgery approaches in 2 years clinical follow-ups. MRI is important not only in diagnostic procedures, but also in neuronavigation of surgery approaches, per operation control of the extent of resections and postoperative follow-ups, especially in failed epilepsy surgery.

Supplementary motor area (SMA) was suggested to have a dominant role in the temporal control of behavior by many neuroimaging studies. The aim of this study was to support this hypothesis by influencing time estimates with theta burst transcranial magnetic stimulation (TMS) over the SMA. Nineteen healthy volunteers with a mean age 25.9±3 (SD) years performed the time reproduction task (TRT) before and after 190 seconds of intermittent theta-burst TMS over SMA and the precuneus (total 600 pulses). The TRT consisted of an encoding phase (during which visual stimuli with durations of 5, 10 and 16.82 seconds were presented pseudorandomly) and a reproduction phase (during which interval durations were reproduced by pressing a button). Mean subjects' interval estimates as a measure of accuracy and standard deviation as a measure of variability pre-TMS and post-TMS were compared. Theta-burst TMS over both areas had no effect on the accuracy of duration estimates. An increased variability of interval reproduction was present after stimulation of the precuneus (p<0.01) with the biggest effect on the five second interval. Stimulation of SMA caused a decrease of variability in the ten second interval only (p<0.05). It is likely that increased variability of time estimates is a non-specific result of impaired attention and working memory after theta-burst TMS. Decreased variability after stimulation over the SMA could be explained in terms of enhanced activity of the physiological oscillator with a frequency close to 0.1 Hz.

Since the somatosensory system is believed to be affected in focal dystonia, we focused on the modulation of the primary somatosensory cortex (SI) induced by repetitive transcranial magnetic stimulation (rTMS) in order to improve symptoms of writer's cramp. Patients with writer's cramp (N=9 in the pilot study and N=11 in the advanced study) were treated with 30-minute 1 Hz real- or sham-rTMS of the SI cortex every day for 5 days. Before and after rTMS, 1.5 T fMRI was examined during simple hand movements. While in the pilot study the rTMS coil was navigated over the SI cortex with a maximum of blood oxygenation-level dependent (BOLD) signal induced by passive movement, patients in the advanced study had the coil above the postcentral sulcus. After real-rTMS, 4 pilot study patients and 10 advanced study patients experienced subjective and objective improvement in writing, while only minimal changes were observed after sham-rTMS. Patients involved in the active movement task exhibited a rTMS-induced BOLD signal increase bilaterally in the SI cortex, posterior parietal cortex and in the supplementary motor area (P<0.001 corrected). After sham-rTMS, no BOLD signal changes were observed. In conclusion, 1 Hz rTMS of the SI cortex can improve writer's cramp while increasing the cortical activity in both hemispheres. Handwriting improved in most patients, as well as the subjective benefit, and lasted for 2-3 weeks. The beneficial effects of rTMS paralleled the functional reorganization in the SI cortex and connected areas, reflecting the impact of somatosensory system on active motion control.