Milos Lucic

Current diagnostic trends in radiology

Since the discovery of X-rays by Wilhelm Conrad Röentgen at the end of the 19th century, diagnostic imaging techniques have been continously improved by technological advances, bringing radiological diagnosis into the very center of modern medicine. Nowadays, it is hard to imagine therapy planning without previous radiological examination. Great advances in the field of computer technology have been accompanied by development of radiological techniques, and today they include not only morphological and anatomical, but also dynamic, functional and molecular imaging. This paper is an overview of new and improved radiological techniques and their implementation.

The functional neuroimaging evidence of cerebellar involvement in the simple cognitive task.

Cerebellar involvement in cognitive functions has been revealed in numerous anatomical, clinical and neuroimaging studies and several hypotheses about potential the role of the cerebellum in higher level brain function have been established. The aim of this study was to show involvement of the cerebellum in simple cognitive tasks. For this matter, we contrasted two tasks from the same semantic domain with specific cognitive content and level of practice: counting forward and counting backward. Twelve volunteers participated in this fMRI study and they were asked to perform both tasks within the same number range (1 to 30 and vice versa). Results showed greater activation in the right cerebellum for the task of counting forward than for counting backward, while for counting backward greater activation was found in prefrontal cortex, supplementary motor area, and anterior cingulate of both hemispheres. Our results correlate with already established hypotheses about cerebellar role in precise and smooth control, not only in well-trained motor but in well trained cognitive tasks as well.

Basal ganglia lesions in the early stage of Menkes disease

An 11-month-old boy presented with progressive truncal hypotonia with poor head control and myoclonic seizures. His hair was sparse and stiff, his skin hypopigmented. Magnetic resonance imaging (MRI) (Fig. 1) demonstrated slight volume loss of the supratentorial white matter, symmetrical T2-weighted (T2W) hyperintense signal of the putamens and isolated round lesions of the left caudate head. The basal ganglia lesions showed restricted diffusion on diffusion-weighted imaging (DWI) (Fig. 2). Light microscopy of the boy’s hair demonstrated pili torti. Low levels of plasma copper and caeruloplasmin confirmed the diagnosis of Menkes disease. Menkes disease is an X-linked recessive disorder of metal metabolism, due to a defect in intracellular– intercompartmental copper transport Bindu et al. (2007), Arita et al. (2009). Typical MRI findings are progressive degeneration of grey and white matter, followed by

Multidisciplinary investigation links backward-speech trait and working memory through genetic mutation.

Case studies of unusual traits can provide unique snapshots of the effects of modified systems. In this study, we report on an individual from a Serbian family with the ability to rapidly, accurately and voluntarily speak backwards. We consider psychological, neural and genetic correlates of this trait to identify specific relevant neural mechanisms and new molecular pathways for working memory and speech-related tasks. EEG data suggest that the effect of word reversal precedes semantic integration of visually presented backward-words, and that event-related potentials above the frontal lobe are affected by both word reversal and the maintenance of backward-words in working memory. fMRI revealed that the left fusiform gyrus may facilitate the production of backward-speech. Exome sequencing identified three novel coding variants of potential significance in the RIC3, RIPK1 and ZBED5 genes. Taken together, our data suggest that, in this individual, the ability to speak backwards is afforded by an extraordinary working memory capacity. We hypothesise that this is served by cholinergic projections from the basal forebrain to the frontal cortex and supported by visual semantic loops within the left fusiform gyrus and that these neural processes may be mediated by a genetic mutation in RIC3; a chaperone for nicotinic acetylcholine receptors.

[Magnetic resonance imaging and bone scintigraphy in bone metastasis detection: a comparative study].

BACKGROUND/AIM Bone scintigraphy is well-known method for the detection of neoplastic lesions with a high sensitivity and, at the same time, a lower specificity. On the other hand magnetic resonance imaging (MRI) is previously established noninvasive imaging method regar ding its diagnostic specificity. The aim of this study was to determine the possibilities and to correlate two different diagnostic methods--bone scintigraphy and MRI in the detection of bone metastasis in the spine and pelvic bones. METHODS A total of 123 patients who underwent both bone scintigraphy and spine and pelvic MRI on 1.5 T MR imager were enrolled in this study. Scans were subsequently analyzed in total and divided in regions of interest (cervical, upper, middle and lower thoracic, upper and lower lumbar and pelvic region, which includes sacral spinal segment); afterwards the total number of 585 mat ching regions were compared and statistically analyzed. RESULTS The statistical analysis demonstrated significant correlation between the findings of both methods in total. Divided by regions of interest, significant degrees of correlation were demonstrated in all of them, except in the cervical spine region where the r-value was in the range of low correlation. CONCLUSION Having a high mutual correlation, bone scintigraphy and MRI are to be considered as the complementary diagnostic methods in the detection of bone metastases. Still, increased diagnostic potential of MRI may highlights negative bone scintigraphy findings in the patients with solitary metastatic lesions or diffuse vertebral infiltration. Advances in the bone scintigraphy (single photon emission tomography--SPECT, SPECT-computed tomography--SPECT-CT) and MRI (whole body MRI, diffusion MRI), make it possible the diagnostic potential of both methods will result in a further improvement in bone metastasis detection.

Dynamic magnetic resonance imaging of the cerebrospinal fluid flow within the cerebral aqueduct by different FISIP 2D sequences

Background/Aim. A vast majority of current radiogical techniques, such as computerized tomography (CT) and magnetic resonance imaging (MRI) have great potential of visualization and delineation of cerebrospinal fluid spaces morphology within cerebral aqueduct. The aim of this study was to determine the possibilities of two differently acquired FISP (Fast Imaging with Steady State Precession) 2D MR sequences in the estimation of the pulsatile cerebrospinal fluid (CSF) flow intensity through the normal cerebral aqueduct. Methods. Sixty eight volunteers underwent brain MRI on 1.5T MR imager with additionally performed ECG retrospectively gated FISP 2D sequences (first one, as the part of the standard software package, with following technical parameters: TR 40, TE 12, FA 17, Matrix: 192 × 256, Acq 1, and the second one, experimentally developed by our investigation team: TR 30, TE 12, FA 70, Matrix: 192 × 256, Acq 1) respectively at two fixed slice positions - midsagittal and perpendicular to cerebral aqueduct, displayed and evaluated by multiplegated images in a closed-loop cinematographic (CINE) format. Results. Normal brain morphology with preserved patency of the cerebral aqueduct in all of 68 healthy volunteers was demonstrated on MRI examination. Cerebrospinal fluid flow within the cerebral aqueduct was distinguishable on both CINE MRI studies in midsagittal plane, but the estimation of intraaqueductal CSF flow in perpendicular plane was possible on CINE MRI studies acquired with experimentally improved FISP 2D (TR 30, FA 70) sequence only. Conclusion. Due to the changes of technical parameters CINE MRI study acquired with FISP 2D (TR 30, FA 70) in perpendicular plane demonstrated significantly higher capability in the estimation of the CSF pulsation intensity within the cerebral aqueduct. .

Prediction of brain atrophy using three drug scores in neuroasymptomatic HIV-infected patients with controlled viremia

BACKGROUND Despite potent antiretroviral therapy, HIV still causes brain damage. Better penetration into the CNS and efficient elimination of monocyte/macrophages reservoirs are two main characteristics of an antiretroviral drug that could prevent brain damage. The aim of our study was to assess efficacy of three antiretroviral drug scores to predict brain atrophy in HIV-infected patients. METHODS A cross sectional study consisting of 56 HIV-infected patients with controlled viremia, who had no clinically evident neurocognitive impairment. All patients had MRI of the head. A typical T2 transversal slice was analyzed and ventricles-brain ratio (VBr) as an overall brain atrophy index was calculated. Three antiretroviral drug scores were used and correlated with VBr: 2008 and 2010 CNS penetration effectiveness scores (ΣCPE2008 and ΣCPE2010) and the recently established monocyte efficacy (ΣME) score. A p-value <0.05 was considered significant. RESULTS ΣCPE2010 was significantly associated with VBr in both univariate (r=-0.285, p=0.033) and multivariate (β=-0.299, p=0.016) regression models, while ΣCPE2008 was not (r=-0.141, p=0.300 and β=-0.156, p=0.214). ΣME was associated with VBr in multivariate model only (r=-0.297, p=0.111 and β=-0.406, p=0.029). Age and reported duration of HIV infection were also significant predictors of overall brain atrophy in multivariate regression models. CONCLUSIONS Although based on similar type of research, ΣCPE2010 is a superior drug score compared to ΣCPE2008. ΣME is an efficient drug score in determining brain damage. Both ΣCPE2010 and ΣME scores should be taken into account in preventive strategies of brain atrophy and neurocognitive impairment in HIV-infected patients.

Color doppler ultrasonography and multislice computer tomography angiography in carotid plaque detection and characterization

BACKGROUND/AIM Cerebrovascular diseases are the third leading cause of mortality in the world, following malignant and cardiovascular diseases. Therefore, their timely and precise diagnostics is of great importance. The aim of this study was to compare duplex scan Color Doppler ultrasonography (CDU) with multislice computed tomography angiography (MSCTA) in detection of morphological and functional disorders at extracranial level of carotid arteries. METHODS The study included 75 patients with 150 carotid arteries examined in the period from January 2008 to April 2009. The patients were firstly examined by CDU, then MSCTA, followed by the surgery of extracranial segment of carotid arteries. In 10 patients, the obtained material was referred for histopathological (HP) examination. We used both CDU and MSCT in the analysis of: plaque surface, plaque structure, degree of stenosis, and the presence of in-traplaque hemorrhage. RESULTS The results obtained by CDU and MSCTA were first compared between themselves, and then to intraoperative findings. Retrospective analysis showed that MSCTA is more sensitive than CDU in assessment of plaque surface (for smooth plaques CDU 89%: MSCTA 97%; for plaques with irregular surface CDU 75% : MSCTA 87%; for ulcerations CDU 54%: MSCTA 87%). Regarding determination of plaque structure (mixed plaque CDU 66% : MSCTA 70%; correlation with HP findings CDU 94% : MSCTA 96%) and localization (CDU 63%: MSCTA 65%), and in terms of sensitivity and specificity, both methods showed almost the same results. Also, there is no statistical difference between these two methods for the degree of stenosis (CDU 96%: MSCTA 98%). CONCLUSION Atherosclerotic disease of extracranial part of carotid arteries primarily affects population of middle-aged and elderly, showing more associated risk factors. Sensitivity and specificity of CDU and MSCTA regarding plaque composition, the degree of stenosis and plaque localization are almost the same. These results and the fact that there are no adverse effects (high radiation dose) compared to MSCTA indicate that CDU should be the initial method in diagnostic algorythm for carotid arteries.

fMRI resting state analysis using empirical mode decomposition

The paper studies connectivity pattern between two functionally specialized brain areas: the primary motor area and the occipital (visual) cortex in the resting state fMRI using empirical mode decomposition (EMD). EMD enables identification of low frequency oscillatory modes in the resting state range [0, 01-0, 1 Hz]. Three frequency modes were determined in the resting state band in 13 subjects with the mean frequencies 0,07Hz, 0,034Hz and 0,016Hz. The temporal correlations among the oscillatory modes were strongest within homologous (corresponding) sources in left and right hemisphere, and weakest between the motor-occipital fMRI signal pairs. The functional connectivity - spatial distribution of temporal correlations in the resting state - has been identified and refined by the oscillatory modes. Connectivity graph obtained across all subjects and all IMFs showed high connectivity rate between homologous areas in the left and right hemisphere and among the visual cortex areas. Combining EMD with the Hilbert transformation may provide an additional tool for exploring correlations between frequency and amplitude ridges in task related problems.

Intradural extramedullary extraosseous Ewing sarcoma/PNET of foramen magnum.

Magnetic resonance imaging (MRI) of the cervical spine was ordered in a 19-year-old male athlete who presented with a left posterior and lateral neck pain. An intradural extramedullary mass showing intense homogeneous contrast enhancement was revealed in foramen magnum, encasing V4 segment of the left vertebral artery and displacing the ventral aspect of medulla oblongata and spinal cord (Fig. 1a, b), associated with perineural spread, affecting left C1 root (Fig. 1c). Partial reduction of the mass was performed. Histological evaluation revealed the presence of Ewing sarcoma (EWS)/peripheral primitive neuroectodermal tumor (pPNET). Complete regression of the tumor was noted after radiation treatment (Fig. 2a). However, cerebrospinal fluid dissemination was evident on follow-up MRI examinations several months later, involving spinal (Fig. 2b) and intracranial compartments (Fig. 2c). Intrathecal chemotherapy was not successful. Lethal outcome occurred 18 months after initial scanning. Foramen magnum tumors are typically benign. Meningiomas and neurinomas are the most frequent. Extraosseous form of EWS/pPNET affecting central nervous system is extremely rare, but should be considered in differential diagnosis of atypical aggressive tumors in young adults. Best to our knowledge, no prior reports of this neoplastic disease, affecting foramen magnum are available. Since most recent investigations indicate that both EWS and PNET share similar neural phenotype and have an identical chromosome translocation, they are considered as the same tumor, differing only in their degree of neural differentiation. The survival depends on the type of genetic rearrangements. The tumor occurs most commonly at the age of 10–30, peak incidence at the age of 15, with a male to female ratio of 1.4:1 [1]. Intracranial primary origin has also been reported [2].