The growing role of telemedicine - possibilities and regulations concerning teleradiology in Poland.

In recent years, imaging studies have become increasingly used at various stages in the management of patients with various conditions and disorders. This process results in a necessity to provide an increasing number of exams, which involves a growing role of radiologists in assessing and reporting those exams. The article discusses tele-radiology as a method that can improve access to radiology services, presenting its potential benefits, as well as the risks involved. It analyses access to radiology healthcare services in Poland in the context of the international and Polish legal provisions concerning the right to healthcare. While funding for imaging studies for patients is widely available and imaging equipment in Poland is improving despite some shortages, the main barrier is identified in the number of specialists capable of assessing the exams. Teleradiology can alleviate this shortage, so the article presents legal provisions and international good practice guidelines in this area, focusing on documents issued by the European Society of Radiology, the American College of Radiology, and the British Royal College of Radiologists. The guidelines concerning such aspects as patients' rights, teleradiologists' qualifications, communication and reporting, responsibility, and technical requirements may help make teleradiology a safe and valuable component of the healthcare system in Poland.

Safety, feasibility, and effectiveness of a CT-guided transthoracic lung and pleural biopsy - a single-centre experience with own low-dose protocol.

Purpose: To assess the efficacy and safety of a low-dose, computed tomography (CT)-guided transthoracic biopsy of lung and pleural lesions. Material and methods: A total of 135 low-dose, CT-guided transthoracic lung and pleural lesions biopsies were performed. A cutting needle was utilized in 124 cases, and fine needle aspiration biopsy was performed in 14 cases. In all cases, 14- to 22-gauge biopsy needles were used. Results: Diagnostic material was obtained in 111 (82.2%) patients. In 97 (71.8%) cases neoplastic lesions were found, predominantly adenocarcinoma and non-small cell carcinoma. In 14 (12.6%) cases non atypical cells were reported. Biopsy failed to obtain material suitable for histopathological examination in 24 (17.7%) cases. Complications occurred in 31 patients, including pneumothorax in 28 patients and haematoma in 3 cases. Conclusions: Based on the obtained results, it can be stated that low-dose, CT-guided transthoracic biopsy of lung and pleural tissues is an accurate and safe procedure. Also, it is linked to a low risk of complications such as a small pneumothorax.

Comparison of dynamic susceptibility contrast enhanced MR and FDG-PET brain studies in patients with Alzheimer's disease and amnestic mild cognitive impairment.

BACKGROUND: The aim of this study was to compare Dynamic Susceptibility Contrast Enhanced MRI (DSC-MRI) and PET with [18F]flurodeoxyglucose (FDG-PET) in the diagnosis of Alzheimer's Disease (AD) and amnestic Mild Cognitive Impairment (aMCI). METHODS: Twenty-seven age-and sex-matched patients with AD, 39 with aMCI and 16 controls underwent brain DSC-MRI followed by FDG-PET. Values of relative Cerebral Blood Volume (rCBV) and rCBV z-scores from frontal, temporal, parietal and PCG cortices were correlated with the rate of glucose metabolism from PET. Sensitivity, specificity and accuracy of DSC-MRI and FDG-PET in the diagnosis of AD and aMCI were assessed and compared. RESULTS: In AD, hypoperfusion was found within all the examined locations, while in aMCI in both parietal and temporal cortices and left PCG. FDG-PET showed the greatest hypometabolism in parietal, temporal and left PCG regions in both AD and aMCI. FDG-PET was more accurate in distinguishing aMCI from the controls than DSC-MRI. In the AD and combined group (AD + aMCI) there were numerous correlations between DSC-MRI and FDG-PET results. CONCLUSIONS: In AD the patterns of hypoperfusion and glucose hypometabolism are similar, thus DSC-MRI may be a competitive method to FDG-PET. FDG-PET is a more accurate method in the diagnosis of aMCI.

The value of different diffusion-weighted magnetic resonance techniques in the diagnosis of middle ear cholesteatoma. Is there still an indication for echo-planar diffusion-weighted imaging?

PURPOSE: The aim of the study was to analyse the value of 2 different diffusion-weighted imaging (DWI) techniques (echo-planar imaging [EPI] and on-echo-planar imaging [non-EPI]) in the diagnosis of cholesteatoma. MATERIAL AND METHODS: Our material consisted of 32 subjects suspected of cholesteatoma, who underwent magnetic resonance imaging of the temporal bone using both EPI and non-EPI DWI. Two independent readers retrospectively analysed magnetic resonance images. Intra- and interobserver agreements as well sensitivity, specificity, and negative (NPV) and positive (PPV) predictive values of both DWI sequences were assessed. RESULTS: Using non-EPI DWI all cholesteatomas were correctly diagnosed by both readers with no false negative nor inconclusive cases and with only one false positive result. Non-EPI DWI revealed high interobserver agreement (k = 1) and high correlation with histopathological results (r = 0.895). EPI DWI misdiagnosed 27-31% of cholesteatomas (false negative results), showing also significantly low interobserver agreement (k = 0.373) and low correlation with histopathological results (r = 0.328 for reader 1 and r = 0.267 for reader 2). Non-EPI DWI revealed very high sensitivity (100%), specificity (83.3%), NPV (100%), and PPV (96.3%) in comparison to EPI DWI, which showed lower sensitivity (69.2%), specificity (66.6-83.3%), NPV (33.3-38.4%), and PPV (90.0-94.7%). CONCLUSIONS: Non-EPI DWI with high sensitivity, specificity, and interobserver agreement is a very reliable technique in detecting middle ear cholesteatoma regardless of the pre- or postoperative state of the ear, and it should entirely replace EPI DWI in clinical practice.

Acute cerebral venous thrombosis - still an underdiagnosed pathology in emergency computed tomography of the brain.

PURPOSE: Acute cerebral venous thrombosis (CVT) is a rare condition that can lead to a serious clinical state; thus, prompt diagnosis and treatment are mandatory. Head computed tomography (CT) plays a crucial role in the initial prompt diagnosis in the emergency setting. The aim of the study was to retrospectively analyse emergency head CT studies and the rate of incorrect diagnoses and main sources of pitfalls. MATERIAL AND METHODS: Retrospective analysis of 31 emergency CT studies (22 without contrast, 19F/12M, age range: 4-94 years) of patients with confirmed acute CVT. RESULTS: Thrombosed dural sinuses were found in 24/31 (77.4%) cases, thrombosed veins in 7/31 (22.6%) cases, no lesions within vessels in 2/31 (6.5%) cases. Haemorrhagic brain lesions were found in 9/31 (29%) cases, hypodense oedema in 6/31 (19.6%) cases, brain swelling in 1/31 (3.2%) cases, and no parenchymal lesions were revealed in 15/31 (48.4%) cases. Correct diagnosis of CVT was established in 15 cases (48.4%); however, it was incorrect in 16 cases (51.6%). Incorrect cases consist of 4 groups: 1 - with both vascular and parenchymal lesions that were overlooked (50%), 2 - with vascular lesions only, which were either overlooked, misinterpreted, or covered by artefacts (31.3%,), 3 - with parenchymal lesions only, which were misinterpreted (12.5%), and 4 - with no lesions present in the emergency head CT (6.2%). CONCLUSIONS: The high rate of incorrect diagnoses of acute CVT based on emergency head CT requires constant training of radiologists and their close cooperation with clinicians because a delayed diagnosis may be lethal to the patient.

A Review of Neuroimaging in Rare Neurodegenerative Diseases.

PURPOSE: Due to the variety of clinical symptoms that occur in rare neurodegenerative diseases and difficulties in the correct diagnosis, there is a need to learn their characteristic imaging findings by using conventional MRI. That knowledge helps to determine the appropriate differential diagnosis and avoid misdiagnosis. The aim of this review is to present the typical neuroimaging signs of the selected neurodegenerative disorders and to create a practical approach to imaging findings useful in everyday clinical practice. Images: Images of progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal degeneration (CBD), Creutzfeldt-Jakob disease (CJD), Wilson's disease (WD), and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) are provided to visualize and distinguish the typical features of those diseases and therefore to assist neurologists and neuroradiologists in decision-making process. CONCLUSIONS: It is important to know the characteristic MRI features of rare neurodegenerative diseases and to use them in everyday clinical practice. MRI is a valuable tool when considering the initial diagnosis because it is proven to be very useful in the differentiation of more advanced stages of the rare neurodegenerative diseases but also from other neurodegenerative disorders.

Standards for European training requirements in interventional neuroradiology : Guidelines by the Division of Neuroradiology/Section of Radiology European Union of Medical Specialists (UEMS), in cooperation with the Division of Interventional Radiology/UEMS, the European Society of Neuroradiology (ESNR), and the European Society of Minimally Invasive Neurological Therapy (ESMINT).

This document sets out standards for training in Interventional Neuroradiology (INR) in Europe. These standards have been developed by a working group of the European Society of Neuroradiology (ESNR) and the European Society of Minimally Invasive Neurological Therapy (ESMINT) on the initiative and under the umbrella of the Division of Neuroradiology/Section of Radiology of the European Union of Medical Specialists (UEMS).

Recommendations of the Polish Medical Society of Radiology and the Polish Society of Neurology for a protocol concerning routinely used magnetic resonance imaging in patients with multiple sclerosis.

Magnetic resonance imaging (MRI) is a widely used method for the diagnosis of multiple sclerosis that is essential for the detection and follow-up of the disease. OBJECTIVE: The Polish Medical Society of Radiology (PLTR) and the Polish Society of Neurology (PTN) present the second version of their recommendations for investigations routinely conducted in magnetic resonance imaging departments in patients with multiple sclerosis. This version includes new data and practical comments for electroradiology technologists and radiologists. The recommended protocol aims to improve the MRI procedure and, most importantly, to standardise the method of conducting scans in all MRI departments. This is crucial for the initial diagnostics necessary for establishing a diagnosis, as well as for MS patient monitoring, which directly translates into significant clinical decisions. INTRODUCTION: Multiple sclerosis (MS) is a chronic immune mediated inflammatory demyelinating disease of the central nervous system (CNS), the aetiology of which is still unknown. The nature of the disease lies in a CNS destruction process disseminated in time (DIT) and space (DIS). MRI detects focal lesions in the white and grey matter with high sensitivity (although with significantly lower specificity in the latter). It is also the best tool to assess brain atrophy in patients with MS in terms of grey matter volume (GMV) and white matter volume (WMV) as well as local atrophy (by measuring the volume of thalamus, corpus callosum, subcortical nuclei, and hippocampus) as parameters that correlate with disability progression and cognitive dysfunctions. Progress in MR techniques, as well as advances in postprocessing the obtained data, has driven the dynamic development of computer programs that allow for a more repeatable assessment of brain atrophy in both cross-sectional and longitudinal studies. MR imaging is unquestionably the best diagnostic tool available to follow up the course of the disease and support clinicians in choosing the most appropriate treatment strategy for their MS patient. However, to diagnose and follow up MS patients on the basis of MRI in accordance with the latest standards, the MRI study must adhere to certain quality criteria. Such criteria are the subject of this paper.

Recommendations of the Polish Medical Society of Radiology and the Polish Society of Neurology for the routinely used magnetic resonance imaging protocol in patients with multiple sclerosis.

Magnetic resonance imaging (MRI) is a widely used method for the diagnosis of multiple sclerosis (MS) that is essential for the detection and follow-up of the disease. The Polish Medical Society of Radiology (PLTR) and the Polish Society of Neurology (PTN) present the second version of the recommendations for examinations routinely conducted in magnetic resonance imaging departments in patients with MS, which include new data and practical comments for electroradiology technicians and radiologists. The recommended protocol aims to improve the MRI procedure and, most importantly, to standardise the method of conducting scans in all MRI departments. This is crucial for the initial diagnostics that are necessary to establish a diagnosis as well as monitor patients with MS, which directly translates into significant clinical decisions. MS is a chronic idiopathic inflammatory demyelinating disease of the central nervous system (CNS), the aetiology of which is still unknown. The nature of the disease lies in the CNS destruction process disseminated in time and space. MRI detects focal lesions in the white and grey matter with high sensitivity (with significantly less specificity in the latter). It is also the best tool to assess brain atrophy in patients with MS in terms of grey matter volume and white matter volume as well as local atrophy (by measuring the volume of thalamus, corpus callosum, subcortical nuclei, hippocampus) as parameters that correlate with disability progression and cognitive dysfunctions. Progress in magnetic resonance techniques, as well as the abilities of postprocessing the obtained data, has become the basis for the dynamic development of computer programs that allow for a more repeatable assessment of brain atrophy in both cross-sectional and longitudinal studies. MRI is unquestionably the best diagnostic tool used to follow up the course of the disease and to treat patients with MS. However, to diagnose and follow up the patients with MS on the basis of MRI in accordance with the latest standards, an MRI study must meet certain quality criteria, which are the subject of this paper.

Interferon-free therapy as the cause of white matter tracts and cerebral perfusion recovery in patients with chronic hepatitis C.

The purpose of this study was to assess cerebral microstructural and perfusion changes in patients with chronic hepatitis C virus (HCV) infection before and after interferon-free therapy, using advanced magnetic resonance (MR) techniques. Eleven HCV-positive patients underwent diffusion tensor imaging (DTI) and perfusion-weighted imaging (PWI) using a 1.5T MR unit, before and 24 weeks after completion of interferon-free therapy. DTI fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained from 14 white matter tracts. PWI values of relative cerebral blood volume (rCBV) and relative cerebral blood flow (rCBF) were assessed from 8 areas, including basal ganglia, and cortical and white matter locations. In HCV-positive patients therapy with ombitasvir, paritaprevir boosted with ritonavir and dasabuvir, with or without ribavirin, was scheduled. Cognitive tests were used to assess cognitive function. We found increased FA values after interferon-free therapy compared to values obtained before treatment in HCV patients in almost all white matter tracts. We also observed elevated rCBV values in basal ganglia after therapy. There were significant correlations between improvement in the score of cognitive tests and increased FA values in both inferior fronto-occipital fascicles and left posterior cingulum after treatment. Liver fibrosis regression in elastography, APRI and improvement in cognitive tests were observed. This is the first report of interferon-free therapy as the cause of white matter tracts recovery as well as cerebral perfusion improvement in HCV-infected patients, indicating better functioning of frontal lobes after interferon-free treatment.

Dual-Energy Computed Tomography in Loosening of Revision Hip Prosthesis: A Comparison Between MARS and non-MARS Images.

PURPOSE: The aim of the study was to assess potential endoprosthesis loosening in patients after revision total hip arthroplasty, based on monochromatic dual-energy computed tomography (DECT) images obtained with and without metal artifact reduction software (MARS) and comparison with the clinical examination and hip function. MATERIALS AND METHODS: Twenty-five consecutive patients underwent DECT examinations. Two monochromatic data sets were generated: with MARS (75-keV MARS) and without MARS (140-keV non-MARS) and evaluated for signs of loosening, using a dedicated radiological score. The Harris Hip Score (HHS) was used to evaluate patients' hip function. RESULTS: The mean radiological score for loosening in the non-MARS group was 16.2, in the MARS group 17.0 and was significantly higher (P < 0.001). Radiological loosening evaluation in non-MARS images correlated with the HHS score (ρ = 0.43, P = 0.03), whereas there was no correlation between MARS images and HHS (ρ = 0.15, P = 0.47). New MARS-related artifacts, which hinder implant-bone interface evaluation, were found in 75-keV MARS images ("pseudo-loosening" in 33 of 34 prostheses, "ground-glass blurring" in 20 of 32). CONCLUSIONS: High-energy monochromatic DECT images are superior to low-energy DECT MARS images in assessment of the potential loosening and correlate better with the clinical examination outcomes. For revision total hip arthroplasty evaluation, 2 data sets should be assessed inseparably because of extra artifacts in MARS images.

The metabolic alterations within the normal appearing brain in patients with Hashimoto's thyroiditis are correlated with hormonal changes.

Hashimoto's thyroiditis (HT) is the most common autoimmune disease in humans usually associated with subsequent hypothyroidism. The purpose of the study was to assess metabolic alterations within the normal appearing brain in subjects with HT using MR spectroscopy (MRS) and to correlate MRS measurements with hormonal concentrations. Fifty-five HT patients (mean age 43.5 yrs) and 30 healthy controls (mean age 42.5 yrs) were examined with the use of a 1.5 T MR scanner. There were no signs of central nervous system involvement in the studied group. The MRS examinations were performed using the single voxel method. The voxels were placed in the left parietal white matter (PWM) and the posterior cingulate gyrus (PCG). The NAA/Cr, Cho/Cr, and mI/Cr ratios were calculated. The correlations between metabolite ratios and hormonal concentrations (TSH, fT3, fT4) as well as anti-TG and anti-TPO levels were also assessed. We found significantly (p < 0.05) decreased NAA/Cr ratios in PCG and PWM in HT subjects compared to the control group. There were no other significant differences in metabolite ratios. We observed significant positive correlations between the NAA/Cr ratio in PCG as well as the PWM and fT3 level. There was also a significant negative correlation between the Cho/Cr ratio in the PCG and fT4 level. MRS could be a sensitive biomarker capable of depicting early cerebral metabolic disturbances associated with HT. Our findings may indicate the reduction of neuronal activity within the normal appearing brain in patients with HT as well as suggesting that there is a possible biological association between thyroid dysfunction and cerebral metabolic changes.

Imaging of cerebrospinal fluid flow: fundamentals, techniques, and clinical applications of phase-contrast magnetic resonance imaging.

Cerebrospinal fluid (CSF) is a dynamic compartment of the brain, constantly circulating through the ventricles and subarachnoid space. In recent years knowledge about CSF has expended due to numerous applications of phase-contrast magnetic resonance imaging (PC-MRI) in CSF flow evaluation, leading to the revision of former theories and new concepts about pathophysiology of CSF disorders, which are caused either by alterations in CSF production, absorption, or its hydrodynamics. Although alternative non-invasive techniques have emerged in recent years, PC-MRI is still a fundamental sequence that provides both qualitative and quantitative CSF assessment. PC-MRI is widely used to evaluate CSF hydrodynamics in normal pressure hydrocephalus (NPH), Chiari type I malformations (CMI), syringomyelia, and after neurosurgical procedures. In NPH precisely performed PC-MRI provides reliable clinical information useful for differential diagnosis and selection of patients benefiting from surgical operation. Patients with CMI show abnormalities in CSF dynamics within the subarachnoid space, which are pronounced even further if syringomyelia coexists. Another indication for PC-MRI may be assessment of post-surgical CSF flow normalisation. The aim of this review is to highlight the significance of CSF as a multifunctional entity, to outline both the physical and technical background of PC-MRI, and to state current applications of this technique, not only in the diagnosis of central nervous system disorders, but also in the further clinical monitoring and prognosis after treatment.

A pictorial essay of the most atypical variants of the vermiform appendix position in computed tomography with their possible clinical implications.

PURPOSE: The tip of the appendix may be located in various areas of the abdominal cavity due to its variable length and/or the changeable position of the caecum. Although in the case of an atypical position the tip is usually located behind the caecum, there are possible locations that occur very rarely. Therefore, in the case of appendicitis the symptoms may lead to the wrong diagnosis. The aim of this study is to present the most atypical locations of the tip of the appendix found on CT (computed tomography) scans and thus help to avoid misdiagnoses. IMAGING FINDINGS: The most unusual locations of the tip of the appendix found in healthy subjects included: left inferior quadrant, along the lower edge of the liver near the gallbladder and the right kidney, the tip touching the duodenum, the rectum or appendages, and a long appendix located in the scrotum as the content of a hernia. In these positions, appendicitis may mimic acute diverticulitis, cholecystitis, duodenal ulcer, duodenitis, enteritis, or adnexal or testis pathologies. CONCLUSIONS: It is important to be aware of atypical locations of the appendix because appendicitis in an unusual area may mimic other acute abdominal diseases and delay the proper treatment.

Bilateral thalamic stroke after tonsillectomy in a patient with collateral extracranial anastomosis - case report.

Haemorrhage remains the most frequent and serious complication of tonsillectomy. When bleeding is recurrent, gushing, and ceases spontaneously, pseudoaneurysm of the injured artery in the proximity of the tonsillar bed should be suspected. Haemorrhage related to pseudoaneurysm occurs most commonly in the first 30 days after surgery. It can sometimes be excessive and requires a revision procedure such as external carotid artery (ECA) ligation or embolisation. During those procedures, ECA should be checked for possible anastomoses, otherwise the bleeding may persist despite the intervention. We report an unusual case of a patient with recurrent post-tonsillectomy haemorrhage due to pseudoaneurysm of the facial artery, which persisted after ECA ligation because of the presence of collateral occipital-vertebral anastomosis. Due to the recurrence of bleeding episodes, endovascular treatment was implemented. However, the embolisation was complicated by bilateral thalamic stroke with unclear mechanism. This case highlights the importance of anastomosis between ECA and the vertebrobasilar system, both in recurrence of significant post-tonsillectomy bleeding and in potential thromboembolic complications. Therefore, ECA ligation should always be accompanied by exclusion of possible anastomoses. In cases of non-life-threatening bleeding, embolisation seems to be the proper and more selective therapy.

Quantitative magnetic resonance assessment of brain atrophy related to selected aspects of disability in patients with multiple sclerosis: preliminary results.

PURPOSE: The aim of this volumetric study was to evaluate the relationship between brain atrophy quantification in multiple sclerosis (MS) patients and the progression of disability measured by neurological standardised tests. MATERIAL AND METHODS: Seventeen patients (mean age 40.89 years) with clinically definite MS and 24 control subjects (mean age 38.45 years) were enrolled in the study. Brain examinations were performed on a 1.5T MR scanner. Automatic brain segmentation was done using FreeSurfer. Neurological disability was assessed in all patients in baseline and after a median follow-up of two years, using EDSS score evaluation. RESULTS: In MS patients we found significantly (p < 0.05) higher atrophy rates in many brain areas compared with the control group. The white matter did not show any significant rate of volume loss in MS patients compared to healthy controls. Significant changes were found only in grey matter volume in MS subjects. At the follow-up evaluation after two years MS patients with deterioration in disability revealed significantly decreased cerebral volume in 14 grey matter areas at baseline magnetic resonance imaging (MRI) compared to MS subjects without disability progression. CONCLUSIONS: Grey matter atrophy is associated with the degree of disability in MS patients. Our results suggest that morphometric measurements of brain volume could be a promising non-invasive biomarker in assessing the volumetric changes in MS patients as related to disability progression in the course of the disease.

The evaluation of the aortic annulus displacement during cardiac cycle using magnetic resonance imaging.

BACKGROUND: The stress in the ascending aorta results from many biomechanical factors including the geometry of the vessel and its maximum dimensions, arterial blood pressure and longitudinal systolic stretching due to heart motion. The stretching of the ascending aorta resulting from the longitudinal displacement of the aortic annulus during the heart cycle has not been examined in the general population so far. The aim of the study is to evaluate this parameter using cardiovascular magnetic resonance (CMR) imaging in the general population in all age groups. METHODS: The cardiac magnetic resonance images of 73 patients were evaluated. The maximum distance to which the ventriculo-aortic junction was pulled by the contracting heart (LDAA - longitudinal displacement of the aortic annulus) was measured in the cine coronal sequences. Moreover, the maximum dimensions of the aortic root and the ascending aorta were assessed. RESULTS: The LDAA value was on average 11.6 ± 2.9 mm (range: 3-19 mm; 95% CI: 10.9-12.3 mm) and did not differ between males and females (11.8 ± 2.9 mm vs. 11.2 ± 2.9 mm, p = .408). The diameter of the ascending aorta was 32 ± 6.3 mm (range: 20-57 mm). The maximal dimension of the aortic root was 35 ± 5.1 mm (range: 18-42 mm). There was a statistically significant negative correlation between the LDAA and the age of patients (r = -.38, p = .001). There was no significant correlation between the LDAA and aortic root dimension (r = .1, p = .409) and between the LDAA and diameter of the ascending aorta (r = .16, p = .170). CONCLUSIONS: Human aortic root and ascending aorta are significantly stretched during systole and the distance to which the aorta is stretched decreases with age. The measurement of the longitudinal displacement of the aortic annulus using the CMR is feasible and reproducible.

Guidelines of the Polish Medical Society of radiology for the routinely used MRI protocol in patients with multiple sclerosis.

Magnetic resonance imaging is widely used in diagnosing multiple sclerosis as a basic method for detecting and monitoring the disease. INTRODUCTION: Polish Medical Society of Radiology presents the second version of the recommendations for the routinely conducted MRI in multiple sclerosis, which include new data and practical remarks for radiographers and radiologists. The recommended protocol aims to improve the imaging procedure and, most importantly, to standardize conducting MRI scans in all MRI departments. This is crucial for monitoring the patients with MS, which directly contributes to essential clinical decisions. AIM OF THE GUIDELINES: Multiple sclerosis (MS) is a chronic inflammatory demyelinating and degenerative disease of the central nervous system (CNS) with its etiology still unknown. The fundamental requirement of the disease is the CNS destruction process disseminated in time (DIT) and space (DIS). MR imaging detects focal lesions in white and gray matter with high sensitivity and is the best way to assess brain atrophy in MS patients. It is unquestionably the best diagnostic tool to follow-up the clinical course of the disease and treatment of MS patients. However, to achieve a diagnosis based on MRI scans, and follow-up MS patients according to the latest standards, an MRI scan has to meet certain quality criteria that are the subject of this work.

Triple-phase abdomen and pelvis computed tomography: standard unenhanced phase can be replaced with reduced-dose scan.

PURPOSE: The aim of the study was to test the hypothesis that unenhanced phase does not require as high image quality as subsequent phases acquired after contrast administration in triple-phase abdomen and pelvis computed tomography (CT), and to assess if attenuation value (AV) measurements may be obtained from unenhanced images acquired with three-fold reduced radiation dose. MATERIAL AND METHODS: In the standard triple-phase abdomen and pelvis CT protocol (unenhanced, late arterial, and portal venous phase) we decreased the tube current time product only in the unenhanced phase. Arterial and venous phases were performed with the standard scanner settings used in our Institution for routine abdomen and pelvis CT. We compared the AV in manually drawn circular-shaped regions of interest (ROIs) obtained from reduced-dose and standard-dose unenhanced images in 52 patients. All ROIs were set in homogeneous parts of psoas muscle, fat tissue, liver, spleen, aorta, and bladder. RESULTS: There was no statistically significant difference in AV measurements for all considered areas. More noise does not alter the mean AV inside the ROIs. Radiation dose of unenhanced scans was reduced three times and the total dose length product (DLP) in the triple-phase study was decreased by 22%. CONCLUSIONS: Unenhanced images performed with three-fold reduced radiation dose allows reliable AV measurements. The unenhanced phase does not require as high image quality as subsequent phases acquired after contrast administration.

The role of diffusion and perfusion magnetic resonance imaging in differentiation of haemangioblastomas and pilocytic astrocytomas.

PURPOSE: Haemangioblastomas (HABLs) and pilocytic astrocytomas (PAs) are brain tumours presenting similar appearance and location in conventional magnetic resonance (MR) imaging. The purpose of our study was to determine whether a detailed analysis of diffusion (DWI) and perfusion (PWI) characteristics can be useful in preoperative differentiation of these tumours. MATERIAL AND METHODS: The study group consisted of biopsy proven six HABLs and six PAs, which underwent preoperative standard MR examinations including PWI and DWI. In PWI relative cerebral blood volume (rCBV) and the shape of perfusion curves (parameters of peak height - rPH and percentage of signal recovery - rPSR) were analysed. All perfusion parameters were measured for the entire tumour core (mean rCBV, mean rPH, mean rPSR) and in regions with maximal values (max rCBV, max rPH, max rPSR). In DWI parameters of apparent diffusion coefficient (ADC) from the entire tumour core (mean ADC) and in regions with minimal values (min ADC) were evaluated. RESULTS: Compared to PAs, HABLs presented significantly higher rCBV and rPH values and lower mean rPSR value. PAs showed significantly lower rCBV and rPH values and higher mean rPSR value. Mean rCBV showed no overlap in the values between HABLs and PAs, and thus it provided the highest accuracy in differentiating between them. Max rPSR, mean ADC, and min ADC did not show any significant differences. CONCLUSIONS: High rCBV values and deep perfusion curves with only partial return to the baseline are characteristic features of HABLs differentiating them from PAs, which show lower rCBV values and perfusion curves overshooting the baseline. Diffusion parameters are not useful in differentiation of these tumours.