Radioisotopic purity and imaging properties of cyclotron-produced 99mTc using direct 100Mo(p,2n) reaction.

Evaluation of the radioisotopic purity of technetium-99m (99mTc) produced in GBq amounts by proton bombardment of enriched molibdenum-100 (100Mo) metallic targets at low proton energies (i.e. within 15-20 MeV) is conducted. This energy range was chosen since it is easily achievable by many conventional medical cyclotrons already available in the nuclear medicine departments of hospitals. The main motivation for such a study is in the framework of the research activities at the international level that have been conducted over the last few years to develop alternative production routes for the most widespread radioisotope used in medical imaging. The analysis of technetium isotopes and isomeric states (9xTc) present in the pertechnetate saline Na99mTcO4 solutions, obtained after the extraction/purification procedure, reveals radionuclidic purity levels basically in compliance with the limits recently issued by European Pharmacopoeia 9.3 (2018 Sodium pertechnetate (99mTc) injection 4801-3). Moreover, the impact of 9xTc contaminant nuclides on the final image quality is thoroughly evaluated, analyzing the emitted high-energy gamma rays and their influence on the image quality. The spatial resolution of images from cyclotron-produced 99mTc acquired with a mini-gamma camera was determined and compared with that obtained using technetium-99m solutions eluted from standard 99Mo/99mTc generators. The effect of the increased image background contribution due to Compton-scattered higher-energy gamma rays (E γ > 200 keV), which could cause image-contrast deterioration, was also studied. It is concluded that, due to the high radionuclidic purity of cyclotron-produced 99mTc using 100Mo(p,2n)99mTc reaction at a proton beam energy in the range 15.7-19.4 MeV, the resulting image properties are well comparable with those from the generator-eluted 99mTc.

Hepatitis C treatment uptake and adherence among injecting drug users in the Czech Republic.

BACKGROUND: Injecting drug users (IDUs) represent a major subpopulation of hepatitis C virus (HCV)-infected people in developed countries. Yet their uptake to treatment is generally low despite well-documented effectiveness of HCV treatment among former and active IDUs. The present study represents the first attempt to describe the HCV treatment coverage among IDUs and identify factors that affect treatment uptake in the Czech Republic. METHODS: From January to March 2011, a questionnaire survey was conducted among viral hepatitis treatment centres in the Czech Republic. RESULTS: From a total of 76 identified hepatitis treatment centres existing in the country, 39 provided HCV treatment to (mainly former or abstaining) IDUs in 2010. Most clinicians reported being cautious in initiating HCV treatment in IDUs. Abstinence, a screening phase before treatment initiation, opioid substitution treatment and an external evaluation by a specialist were often prerequisites for skrting treatment. However, HCV treatment centres rarely provided drug-use specific services. Financial constraints were also reported, further limiting the inclusion of IDUs into treatment, as non-users are widely preferred to active drug users. Clinicians reported no difference in treatment uptake and adherence between drug users and non-users, nor between opioid and methamphetamine users. CONCLUSION: A number of system- and provider-related factors limit HCV treatment in IDUs in the Czech Republic, despite permissive national clinical guidelines. Targeting these factors is crucial to reduce HCV prevalence at population level.

Intracranial vascular malformations.

Many efforts and much research have been dedicated to the field of non-invasive angiographic techniques in the past few years. Thanks first to magnetic resonance angiography (MRA) and subsequently to computed tomographic angiography (CTA), very interesting results have been obtained in the diagnosis of cerebrovascular diseases. Neck vessels are most successfully evaluated by both MRA and CTA, and the need for digital subtraction angiography (DSA) examinations in patients at risk for vascular occlusions has significantly decreased. The role and the diagnostic accuracy of these non-invasive modalities in intracranial vascular pathology is still under investigation, and several studies have been and are being performed. Both techniques have a better spatial resolution and sensitivity in detecting cerebrovascular malformations than DSA. In the diagnosis of cerebral aneurysms, both MRA and CTA - due to their high sensitivity - have become screening techniques in the population at risk for subarachnoid hemorrhage, these techniques may become basic diagnostic modalities in treatment planning. The results are less satisfying in the evaluation of brain arteriovenous malformations and in the different steps of pre- and post-therapeutic evaluation.

Magnetic resonance imaging in progressive supranuclear palsy and other parkinsonian disorders.

High field intensity MRI may demonstrate signal abnormalities consistent with deposits of iron or other paramagnetic substances in several extrapyramidal disorders. Hallervorden-Spatz disease was the only disorder widely known to have iron deposits in the pallidum, that are now easily demonstrated in vivo by MRI. However, lower field intensity MRI may also demonstrate characteristic findings. In progressive supranuclear palsy, definite atrophy of the midbrain and of the region around the third ventricle is seen in slightly more than half of the cases. Minimal signal abnormalities are sometimes seen in the periaqueductal region, but MRI studies remain of little help in establishing the diagnosis of the disease. Asymmetric atrophy in the parietal regions is seen in corticobasal degeneration, as expected from pathological studies. Minimal alterations may be seen in the substantia nigra in Parkinson's disease. The most interesting MRI findings are observed in multiple system atrophies. Variable abnormal signal intensities, depending on the field intensity, are visible in the putamen in striatonigral degeneration and in Shy-Drager syndrome; in this latter condition the abnormalities are due to its striatonigral degeneration component. Atrophy of the pons, middle cerebellar peduncles, and cerebellum, and signal abnormalities in a characteristic distribution are visible in olivopontocerebellar atrophy. A combination of these posterior fossa abnormalities and putaminal alterations may confirm the involvement of the cerebellar and extrapyramidal systems in multiple system atrophies.

Multiple system atrophy. Clinical and MR observations on 42 cases.

Probable or possible multiple system atrophy (MSA) was diagnosed on strict clinical criteria in 42 patients: 20 with combined parkinsonism and cerebellar ataxia, 9 with striatonigral degeneration (SND) and 13 with olivopontocerebellar atrophy (OPCA). All patients were then studied with 0.5 and/or 1.5 Tesla magnetic resonance (MR) units. MR imaged putaminal abnormalities in all 9 patients with SND and posterior fossa abnormalities consistent with OPCA in all 13 patients with this diagnosis. Of the 20 patients with parkinsonism and cerebellar involvement, classified as probable MSA, 7 presented putaminal abnormalities only, 3 abnormalities consistent with OPCA only and 10 a combination of both. These findings show strong MRI support for the clinical diagnosis of MSA.

Hallervorden-Spatz disease: MR and pathologic findings.

PURPOSE: To compare the MR findings of eight cases with clinical diagnosis of Hallervorden-Spatz disease (HSD) with the pathologic findings of two other cases of HSD. MATERIALS AND METHODS: The eight imaged cases were studied with 0.5-T (seven cases) and/or 1.5-T (five cases) units. Six patients also had CT scans. The two other cases with proven HSD had detailed histologic evaluation. RESULTS: The 1.5-T findings showed abnormalities confined to the pallidum, which presented a diffuse low signal intensity in T2-weighted images, and an anteromedial area of high signal intensity (eye-of-the-tiger sign). In 0.5-T studies, low signal intensity was less evident and poorly detectable in spin echo, but gradient-echo images could enhance its demonstration; the area of high signal intensity was always well demonstrated. In three cases (three with 1.5 T, one with 0.5 T) a central spot of low signal intensity was seen in this area. The pathologic cases, in addition to neuroaxonal swellings and iron deposits, exhibited areas of "loose" tissue with vacuolization and lesser amounts of iron in the anteromedial part of the pallidum, in a location corresponding to the area of high signal intensity of the imaged cases. CONCLUSION: Comparison of MR findings with the pathologic studies demonstrates that the low signal intensity in T2-weighted images at 1.5 T corresponds to iron deposits in a dense tissue, and that the high signal intensity of the eye-of-the-tiger sign corresponds to an area of loose tissue with vacuolization. No correlation was found in the two pathologic cases for the central spot of low signal intensity.

Clinical and magnetic resonance features of the classic and akinetic-rigid variants of Huntington's disease.

We studied 32 patients with confirmed Huntington's disease (HD); six (mean age, 31.7 years) had the akinetic-rigid form and 26 (mean age, 46.1 years) had the classic hyperkinetic form. Clinical examination included a count of abnormal involuntary movements, motor self-sufficiency evaluation by the Physical Disability Rating Scale, cognitive function assessment by the Mini-Mental State examination, and a verbal fluency test. Magnetic resonance imaging permitted measurement of bicaudate diameter, a sensitive indicator of caudate atrophy in HD. Patients with the akinetic-rigid form of HD were younger and had earlier disease onset than those with the classic form of HD. All patients with akinetic-rigid HD (group 1) had striatal hyperintensity on T2-weighted magnetic resonance images; seven patients with classic HD (group 2) had a similar abnormality. Groups 1 and 2 were in fact similar in all other respects, except that the number of abnormal involuntary movements was greater in group 2. Groups 1 and 2 together had significantly younger age at onset, lower Mini-Mental State Examination score, more severe motor disability, worse verbal fluency test result, and greater bicaudate diameter than the 19 patients with classic HD without magnetic resonance signal abnormality (group 3) and appear to be a uniform population, distinct from group 3. The abnormalities on magnetic resonance images indicated greater striatal damage in groups 1 and 2, which could be the neuroanatomic substrate of their greater motor and cognitive compromise.

Hallervorden-Spatz disease: clinical and MRI study of 11 cases diagnosed in life.

The diagnosis of Hallervorden-Spatz disease (HSD) has usually been made post mortem, although the recent description of characteristic abnormalities in the globus pallidus has suggested the possibility of an in vivo diagnosis. We present the clinical histories, neurological features and MRI findings of 11 patients, diagnosed as having HSD. Generalized dystonia with predominance of oromandibular involvement, behavioural changes followed by dementia and retinal degeneration were present in all the patients. MRI pallidal abnormalities consisted of decreased signal intensity in T2-weighted images, compatible with iron deposits, and of a small area of hyperintensity in its internal segment ("eye of the tiger" sign). We propose that the combination of these neurological signs with these MRI findings could be considered as highly suggestive of a diagnosis of HSD in living patients.

Gliomatosis cerebri. Report of a case with isolated amnesic disorders.

We describe the case of a female patient with behavioral and memory disorders. A neuropsychological evaluation confirmed the absence of mental deterioration and the presence of the psychometric features of the amnesic syndrome. The clinical diagnosis was supported by MRI and histological examination.

Spinal cord lesion after penicillin gluteal injection.

Penicillin gluteal injection may cause sudden and irreversible paraplegia. In the literature 6 cases have been reported, and spinal infarction was conjectured, the mechanism being obscure. The actual incidence of such a complication is not known. We observed 2 more cases, 6 and 16 years respectively following such an injection. The clinical features suggested that spinal infarction had occurred, and an MRI study in the most severely impaired patient showed marked spinal atrophy, giving further support to the spinal infarction hypothesis. These findings and the pathophysiological considerations suggest that the mechanism might be the accidental injection into the superior gluteal artery, causing its distal spasm and the upstream ascent of the penicillin with ensuing embolic and/or spastic occlusion of the arterior spinal artery.

Abnormal MRI signal in the rigid form of Huntington's disease.

Eighteen patients with Huntington's disease (HD) were examined with MRI. Eleven had the common hyperkinetic form, seven had the rigid variant. All seven patients with rigid HD had increased signal intensity in the neostriatum in intermediate and T2-weighted images. Only one hyperkinetic HD had similar findings. In all the other cases, signal abnormalities were questionable or absent. Histological differences that account for differences in signal intensity may therefore lie in the caudate nucleus and putamen. Age of onset may be important, since the rigid patients were younger. Follow up studies may help in understanding these signal differences.

Short-lasting unilateral neuralgiform headache attacks with tearing and conjunctival injection: the first "symptomatic" case?

A 36-year-old man was suffering from brief, unilateral and short-lasting pain attacks always associated with marked homolateral tearing and conjunctival injection, both presenting in a cluster fashion. An arteriovenous malformation was subsequently discovered in the homolateral cerebellopontine angle. The clinical picture shares similarities with both cluster headache and trigeminal neuralgia, although it can not be accurately placed with either of these forms. Patients with similar symptoms have previously been described in detail, and on the basis of these few descriptions a new syndrome "short-lasting" unilateral neuralgiform headache attacks with conjunctival injection, tearing, sweating, and rhinorrhoea has been postulated. Assuming the validity of this syndrome as an entity, this case is in all probability its first "symptomatic" example. Careful evaluation of the varieties of cluster headache and trigeminal neuralgia, and the reporting of similar new cases as they arise are necessary to establish the nosologic boundaries of this syndrome.

Olivopontocerebellar atrophy: MR diagnosis and relationship to multisystem atrophy.

Clinical diagnosis of olivopontocerebellar atrophy (OPCA) must be confirmed by radiologic demonstration of atrophy in an appropriate distribution. OPCA may be associated with degeneration of other systems in multisystem atrophy (MSA). The authors report 23 cases of OPCA, eight of which were associated with MSA. Atrophy involved the cerebellum, pons, and middle cerebellar peduncles in all cases. On intermediate and T2-weighted magnetic resonance (MR) images, abnormal signal intensity was always observed in the transverse pontine fibers, middle cerebellar peduncles, and cerebellum, structures known from pathologic study to degenerate in OPCA. Pyramidal tracts and superior cerebellar peduncles stood out because of their normal signal intensity. Of the eight patients with MSA, four also had variable abnormal signal intensities in the putamen. The authors believe that the combination of atrophy and abnormal signal intensity in the appropriate distribution strongly supports the diagnosis of OPCA. In some cases, MR imaging may demonstrate involvement of different systems, thus confirming the diagnosis of MSA.

Technical basis for magnetic resonance images.

The spin-echo procedure is the basic technique in a magnetic resonance (MR) study (the magnetization vector is flipped by 90 degrees onto the ortogonal plane to the main magnetic field). Very soon after the MR procedure was developed, it was pointed out how important it is to achieve the needed contrast with shorter repetition times (TRs) to reduce the imaging time. Recently, fast imaging techniques have been introduced (partial flip angles, short TRs, and the lack of 180 degrees radiofrequency pulses to refocus the spins are their main characteristics; the spins are refocused by the application of a gradient reversal technique). These techniques are particularly needed in pediatric neuroradiology, where the examination time must be as short as possible. At present, partial flip-angle techniques are almost completely replacing the conventional spin-echo procedure, but the variations in flip angle could result in a change in contrast. For these reasons, conventional spin-echo techniques may still be useful in a routine MR study.

MR imaging in progressive supranuclear palsy and Shy-Drager syndrome.

Previous reports have suggested that putaminal hypointensity in T2-weighted images at high field strength (1.5 T) magnetic resonance (MR) is a common finding in atypical parkinsonian syndromes, including progressive supranuclear palsy (PSP) and Shy-Drager syndrome (SDS). We have reviewed nine patients with PSP and five with SDS, selected on strict clinical criteria. Only in one PSP patient was abnormal signal intensity (putaminal hypointensity more marked than pallidal) found. However, hypointensity was often marked in the substantia nigra and occasionally in the superior colliculi. Focal midbrain atrophy, involving particularly the upper part of the quadrigeminal plate, was obvious in five cases. In general there was no uniformity of findings and MR appears unable to consistently support the clinical diagnosis of PSP. In SDS patients the findings were more uniform, with hypointensity in the putamen, superior or equal to that of the pallidum. At low or intermediate field strength, there was absence of magnetic susceptibility effect in the putamen, which appeared hyperintense. This was probably because of increased water content due to gliosis and/or cell loss. The constancy of the MR findings in our SDS series suggests a supportive diagnostic role for MR imaging.

Neurobrucellosis mimicking multiple sclerosis: a case report.

A case of neurobrucellosis misdiagnosed at the onset as multiple sclerosis (MS) is presented. Magnetic resonance imaging showed multiple periventricular areas compatible with demyelinating lesions of possible vasculitic origin. Myelin basic protein was elevated in the CSF. The immunological CSF study was consistent with a chronic intrathecal inflammatory process. The modification of these parameters during specific treatment is also presented.

Intra-arterial digital subtraction angiography of vascular lesions of the spinal cord. Personal experience.

IDSA studies were performed in 6 patients with AVM and hemangioblastomas of the spinal cord. IDSA appears to be the most suitable angiographic approach for the study and embolization of this kind of lesions of the spinal cord even when special conditions require repeating some injections on conventional angiography.