Auditory hallucinations and migraine of possible brainstem origin.

BACKGROUND: Concurrence of migraine and hallucinations is extremely rare and the underlying mechanism is poorly understood. METHODS: We report a 22-year-old man with migraine associated with auditory hallucinations. Concurrent psychotic illness has been excluded. RESULTS: Brain MR scans showed a stable, patchy FLAIR hyperintensity over the posterolateral aspect of the left cerebral peduncle, just below the level of the red nucleus. This was felt to represent an area of gliosis based on the interval stability over 19 months. There was absence of features for aggressive neoplasms, such as lesional high cellular turnover (choline/NAA ratio >1.0) or high cerebral blood volume on advanced MR imaging with MR spectroscopy and dynamic perfusion MR. EEG and brainstem auditory evoked potentials were unremarkable. CONCLUSIONS: To our knowledge, there are no reports to date on similar auditory hallucinations in adult migraine patients, as well as with associated MRI brainstem lesions. The peduncular lesion could represent a previous migrainous infarct, and a possible analogy can be drawn from the descriptions of peduncular hallucinosis. Brainstem lesions, particularly in the midbrain and pons, have rarely been associated with this condition. It has been postulated that the damage to ascending reticular systems or thalamocortical circuitry may contribute to its pathogenesis.

Thermoresponsive core-shell magnetic nanoparticles for combined modalities of cancer therapy.

Thermoresponsive polymer-coated magnetic nanoparticles loaded with anti-cancer drugs are of considerable interest for novel multi-modal cancer therapies. Such nanoparticles can be used for magnetic drug targeting followed by simultaneous hyperthermia and drug release. Gamma-Fe(2)O(3) iron oxide magnetic nanoparticles (MNP) with average sizes of 14, 19 and 43 nm were synthesized by high temperature decomposition. Composite magnetic nanoparticles (CNP) of 43 nm MNP coated with the thermoresponsive polymer poly-n-isopropylacrylamide (PNIPAM) were prepared by dispersion polymerization of n-isopropylacrylamide monomer in the presence of the MNP. In vitro drug release of doxorubicin-(dox) loaded dehydrated CNP at temperatures below and above the lower critical solution temperature of PNIPAM (34 degrees C) revealed a weak dependence of drug release on swelling behavior. The particles displayed Fickian diffusion release kinetics; the maximum dox release at 42 degrees C after 101 h was 41%. In vitro simultaneous hyperthermia and drug release of therapeutically relevant quantities of dox was achieved, 14.7% of loaded dox was released in 47 min at hyperthermia temperatures. In vivo magnetic targeting of dox-loaded CNP to hepatocellular carcinoma (HCC) in a buffalo rat model was studied by magnetic resonance imaging (MRI) and histology. In summary, the good in vitro and in vivo performance of the doxorubicin-loaded thermoresponsive polymer-coated magnetic nanoparticles suggests considerable promise for applications in multi-modal treatment of cancer.

Case control study of diffusion tensor imaging in Parkinson's disease.

BACKGROUND: Preliminary work has shown that diffusion tensor MRI (DTI) may contribute to the diagnosis of Parkinson's disease (PD). OBJECTIVES: We conducted a large, prospective, case control study to determine: (1) if fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values on DTI in the basal ganglia and substantia nigra are different between patients with PD and healthy controls; and (2) the predictive value of these parameters and their clinical utility. METHODS: DTI imaging was carried out in patients with PD and controls. FA and ADC values were obtained from various brain structures on the DTI scan using the diffusion tensor taskcard. The structures studied were: caudate, putamen, globus pallidus, thalamus and substantia nigra. RESULTS: 151 subjects (73 PD patients, 41 men, 32 women; mean age 63.6 years) and 78 age and sex matched control subjects were studied. The FA value of the substantia nigra in patients with PD was lower compared with controls (0.403 vs 0.415; p = 0.001). However, no significant differences were demonstrated for FA or ADC values of other structures. Multiple regression analysis revealed that the clinical severity of PD correlated inversely with the FA value in the substantia nigra in patients with PD (regression coefficient -0.019). No single FA value had both a high positive and negative predictive power for PD. CONCLUSIONS: We demonstrated in a large, prospective, case control study that the FA value in the substantia nigra on DTI was lower in PD compared with healthy controls, and correlated inversely with the clinical severity of PD. Further longitudinal studies would be helpful to assess the clinical utility of serial FA measurements of the substantia nigra in objective quantification of disease progression and monitoring of the therapeutic response.

Intravoxel incoherent motion and diffusion tensor imaging of early renal fibrosis induced in a murine model of streptozotocin induced diabetes.

INTRODUCTION: To assess if parameters in intravoxel incoherent motion (IVIM) and diffusion tensor imaging (DTI) can be used to evaluate early renal fibrosis in a mouse model of diabetic nephropathy. MATERIALS & METHODS: In a population of 38 male CD1 mice (8weeks old, 20-30g), streptozotocin induced diabetes was created in 20 mice via a single intraperitoneal injection of streptozotocin at 150mg/kg, while 18 mice served as control group. IVIM parameters were acquired at 0, 12 and 24weeks after injection of streptozotocin using a range of b values from 0 to 1200s/mm2. DTI parameters were obtained using 12 diffusion directions and lower b values of 0, 100 and 400s/mm2. DTI and IVIM parameters were obtained using region of interests drawn over the renal parenchyma. Histopathological analysis of the right kidney was performed in all mice. Results were analyzed using an unpaired t-test with P<0.05 considered statistically significant. RESULTS: Renal cortex fractional anisotropy (FA) was significantly lower in the diabetes group at week 12 as compared with the control group. Renal cortex apparent diffusion coefficient and tissue diffusivity were significantly higher in the diabetes group at week 12 compared with the control group at 12weeks. Blood flow was significantly decreased at the renal medulla at 24weeks. Histopathological analysis confirmed fibrosis in the diabetes group at 24weeks. CONCLUSION: FA is significantly reduced in diabetic nephropathy. FA might serve a potential role in the detection and therapy monitoring of early diabetic nephropathy.

Putaminal Diffusivity Correlates With Disease Progression in Parkinson's Disease: Prospective 6-Year Study.

Diffusion tensor imaging (DTI) is an increasingly used noninvasive imaging tool. However its long-term clinical utility is unclear. Parkinson's disease (PD) is a common neurodegenerative disease.We prospectively examined a cohort of 46 Parkinson's disease (PD) patients who underwent diffusion tensor imaging (DTI) of the brain at baseline and 6 years later on a 1.5 Tesla scanner using a standardized protocol. DTI parameters of mean diffusivity (MD) and fractional anisotrophy (FA) were extracted using regions-of-interest (ROIs) analysis from various brain regions.Compared to the baseline scan, MD increased in all brain regions (P < 0.0001). FA increased in the substantia nigra and posterior putamen, but decreased in the frontal white matter (P < 0.0001). Linear regression analysis demonstrated that the MD in the anterior putamen increased 11.6 units (95% CI = [4.71, 18.43]) (P = 0.0003) for every unit increase of United PD Rating Scale (UPDRS).Our 6-year prospective longitudinal study demonstrated increased diffusivity in all brain regions and that in the anterior putamen correlated with disease progression. Serial diffusion data may be useful as an additional objective in vivo biomarker for motor progression in PD.

Temporal lobe necrosis following radiation therapy for nasopharyngeal carcinoma: 1H MR spectroscopic findings.

PURPOSE: To observe the patterns of radiation-induced temporal lobe necrosis (TLN) following radiation therapy for nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS: Twenty-five proton magnetic resonance spectroscopic (1H MRS) examinations were acquired from 13 healthy adult volunteers for comparison with data from the patient population. There were 18 patients (28 spectra) with radiologic evidence of TLN and all patients were confirmed cases of NPC treated with radiation therapy. Six patients (33%) had a single treatment while 12 (67%) patients had two treatments. All 1H MRS examinations were performed on a 2-T whole body system (Bruker) using the point-resolved spectroscopy (PRESS) method with TE = 135 ms, TR = 3000 ms, and data processed automatically using the LCModel software package for metabolite quantification. RESULTS: The N-acetyl-aspartate (NAA) levels were reduced in all except one spectrum (96%). Choline (Cho) was increased in 3 (11%), normal in 4 (14%), and reduced in 21 (75%) spectra. The creatine (Cr) level was normal in 8 (29%) spectra and reduced in 20 (71%) spectra. In four patients with normal imaging findings 1H MRS was abnormal. CONCLUSION: 1H MRS can characterize radiation-induced TLN. Spectra with increased Cho can be mistaken for neoplasm. Spectroscopy can also identify metabolic derangement before imaging.

Spermine reduces infarction and neurological deficit following a rat model of middle cerebral artery occlusion: a magnetic resonance imaging study.

The role of nitric oxide (NO) in post-ischemic cerebral infarction has been extensively examined, but few studies have investigated its role on the neurological deficit. In the present study, we investigated the effect of spermine on the temporal evolution of infarct volume, NO production and neurological deficit using magnetic resonance imaging in a model of permanent focal cerebral ischemia in rats. Spermine given at 10 mg/kg 2 h after ischemia reduced the infarct volume by 40% and abolished brain NO production and improved the neurological score 24 h, 48 h and 72 h after ischemia. Spermine also reduced the neurological deficit as evaluated by rotamex, grip strength and neurological severity score tests.

Lasting cytotoxic edema as an indicator of irreversible brain damage: a case of neonatal stroke.

We describe a case of neonatal stroke in the territory of the left middle cerebral artery. Although the ischemic lesion appeared rather homogeneously hyperintense on T2-weighted MR images, corresponding diffusion-weighted images clearly delineated two separate zones of different cellular swelling and, thus, different prognoses. Lasting cytotoxic edema heralded infarction. We believe that the different rates of disintegration of neurons and glial cells may have caused the change from intracellular to interstitial volume fraction during the evolution of edema.

The application of 3D chemical shift microscopy to noninvasive histochemistry.

Three-dimensional chemical shift imaging methods offer significant advantages over two-dimensional (chemical shift selective) techniques for the study of biological samples which exhibit complex spectra. We have applied 3D-CSI methods to the study of a plant system, (dried fennel mericarps) previously studied by 2D-CSI techniques, obtaining images with in-plane resolution down to 30 microns and special resolution of 0.4 ppm. A modification of the 3D-CSI technique which incorporates water suppression by a combination of pre-saturation and selective excitation is also described and its performance evaluated on both a phantom and a fresh fennel sample.

Applications of chemical-shift-selective NMR microscopy to the non-invasive histochemistry of plant materials.

Chemical-shift-selective imaging at microscopic resolution has been applied to the study of various plant materials including orange peel, grape berries and both dried and undried fruits of fennel. It is shown that selective imaging of aromatics and carbohydrates as well as water and oil can be performed with in-plane resolution down to 13 microns and slice thicknesses of 1 mm or less, at a field strength of 4.7 Tesla. The noninvasive nature of the method gives it advantages over established methods of plant histochemistry which involve sectioning and staining to reveal different chemical constituents.

Neurological changes following radiation therapy for head and neck tumours.

Radiation therapy is widely used in the treatment of head and neck tumours either as a primary form of treatment or a supplementary modality. Although the benefits of radiation therapy are well established, this treatment modality is not without untoward consequences and complications. The intent of this paper is to highlight the neurological complications that may follow the treatment for head and neck malignancies, in particular, following radiation therapy for nasopharyngeal carcinoma.

Imaging of finger joints in a whole-body MR system using a simple and low-cost solenoidal coil.

This work considers the design and operation of a solenoid radiofrequency (RF) coil for magnetic resonance (MR) mini-imaging of finger joints using a whole-body system. The considerations were focused on the requirements of high sensitivity, easy patient access, and cost-effectiveness. The proposed design is a short, two-turn solenoidal coil that accomplishes high spatial uniformity over a 2-cm region of interest (ROI). The coil resembles an oversized ring, and easily fits fingers that are spread. An experimental demonstration of the proposed approach is given by imaging the proximal interphalangeal joint in healthy volunteers using a 2.5-cm field of view (FOV). Spin-echo and gradient-recalled-echo T1-weighted sequences, and a 3D spoiled-gradient-echo sequence were used.

Late glial swelling after acute cerebral hypoxia-ischemia in the neonatal rat: a combined magnetic resonance and histochemical study.

Secondary brain damage after transient cerebral hypoxia-ischemia (HI) is caused by a cascade of cellular events. In this study, complementary methods of magnetic resonance imaging and histochemistry were used to investigate the formation of cytotoxic and vasogenic edema during secondary brain damage induced by transient HI in 7-d-old rats. To elicit injury, 21 rats underwent right common carotid artery ligation followed by 1.5 h of 8% O2 exposure. Sequential apparent diffusion coefficient (ADC) and transversal relaxation time (T2) weighted magnetic resonance imaging were recorded for up to 3 d in 13 7-d-old rats. Eight animals were killed at various intervals between the end of HI and 21 h of recovery to perform histochemical assays using neuronal and astrocytic markers. Changes of the ADC revealed a biphasic function for the evolution of cytotoxic edema during the recovery period. At the end of HI, the ADC in the ipsilateral cortex was significantly decreased. Upon reoxygenation, it returned transiently to normal followed by a secondary, although less pronounced, decline after 8-48 h. After this, the ADC rose steadily. From 8 h of recovery, the proportion of vasogenic edema steadily increased as indicated by the T2 prolongation. At 21 h, the majority of glial cells showed immunoreactivity for glial fibrillary acidic protein and were of larger size, whereas the neurons were apoptotic. These results indicate that the delayed cerebral injury is accompanied by late glial swelling in conjunction with an enlarged interstitial space due to cell damage.

[NMR-microscopic studies of the condylar cartilage of the temporomandibular joint]. / NMR-mikroskopische Untersuchungen am kondylären Knorpel des Kiefergelenks.

The objectifying of growth mechanisms of the TMJ is very important for orthodontic diagnosis, treatment as well as clinical research. Condylar cartilage of the TMJ from neonatal pigs was investigated on in vivo preparations by NMR-microscopy. NMR-micro-pictures and histologic slide preparations of condylar cartilage were compared and discussed in connection with its implications for treatment with functional appliances.

Developmental changes of phosphorus metabolite concentrations in the human brain: a 31P magnetic resonance spectroscopy study in vivo.

Phosphorus magnetic resonance spectroscopy is a noninvasive method to investigate brain metabolism in vivo. ATP generally serves as an internal concentration standard for the quantification of the various phosphorus metabolites, because the ATP concentration in mammalian brains is assumed to be age independent. This presumption is based on observations made in the biochemical analysis of the developing rat brain. In the present study, metabolite concentrations were assessed with an external concentration standard. Each brain spectrum was quantified using a calibration spectrum that was acquired from a phantom after the in vivo brain measurement. Fully relaxed localized brain spectra were obtained from 16 neonates (2-28 d), 17 infants (6-20 mo), and 28 adults (22-58 y). The metabolite concentrations (in mmol/L) changed from neonates to adults: phosphomonoester from 4.5 to 3.5, inorganic phosphate from 0.6 to 1.0, phosphodiester from 3.2 to 11.7, phosphocreatine from 1.4 to 3.4, and ATP from 1.6 to 2.9. We conclude that 1) the ATP concentration in the human brain almost doubles between neonates and adults, and 2) ATP may not be used as an age-independent internal concentration standard.

MR microimaging of articular cartilage and contrast enhancement by manganese ions.

Saline solutions of manganese ions (Mn2+) were used as articular contrast agents in magnetic resonance microscopy (9.4 T) of cartilage of chicken femoral condyles and pig temporomandibular joints. The diffusion of Mn2+ from the articular surface into the cartilage matrix led to a strong contrast enhancement in the cartilage. The combination of the high spatial resolution and the contrast enhancement allowed the visualization of fine structures (tissue types) in the cartilage, which correlate with the tissue zones in histological sections stained with cationic dyes. We assume that the electrostatic interactions between the negatively charged groups of the proteoglycans and Mn2+ are most important for the mechanism of contrast enhancement. Hence, the different signal intensities of the various zones of cartilage indicate differences in density of proteoglycans. The intraarticular injection of the cationic contrast agent could improve the possibility of an early diagnosis of cartilage dysfunction and degeneration.

Magnetic resonance imaging of brain edema in the neonatal rat: a comparison of short and long term hypoxia-ischemia.

Diffusion-weighted and transversal relaxation time (T2)-weighted magnetic resonance imaging were used to study the relationship between the duration of hypoxia-ischemia [unilateral common carotid artery (CCA) ligation and exposure to 8% oxygen] and the in vivo visualization of brain edema in 7-d-old rats. After CCA ligation, 35 animals were divided into five groups according to the length of exposure to 8% oxygen: no exposure (n = 9), 15 min (n = 12), 30 min (n = 5), and 1 h (n = 9) exposure; six animals served as controls. Diffusion weighted images were acquired 2 h after the hypoxic-ischemic insult, sequential T2 weighted images were recorded for up to 7 d and the outcome was documented by histologic examination at 21 d. The apparent diffusion coefficient of water in the ipsilateral cortex was significantly decreased in all animals recovering from prolonged hypoxic-ischemic insult (30 min and longer), whereas this was the case in only 40% of animals exposed to 15 min of hypoxia. Moreover, T2 prolongation of brain tissue occurred only in the former group. These results indicate transient and reversible alterations of physiologic water compartmentation for short term hypoxia-ischemia, but irreversible edema formation for long term hypoxia-ischemia. They support the hypothesis that the duration of hypoxia-ischemia determines whether a vasogenic edema and infarction follows the initial cytotoxic edema.

Temporal lobe changes following radiation therapy: imaging and proton MR spectroscopic findings.

Radiation therapy for nasopharyngeal carcinoma affects the temporal lobes. This paper characterizes proton MR spectroscopic findings of the temporal lobes and correlates them with imaging changes. Single-voxel proton MR spectroscopic examinations were acquired from 13 healthy adult volunteers (25 spectra) and 18 patients (28 spectra). All patients had biopsy-confirmed nasopharyngeal carcinoma and were previously treated with radiation therapy. Six patients (33%) had a single treatment and 12 (67%) patients had two treatments. Point resolved spectroscopy (PRESS) method was used (TR = 3,000 ms, TE = 135 ms) and data processed automatically using the LCModel software package for metabolite quantification. Voxel size and geometry were adapted to the lesion to reduce skull-base lipid contamination. The metabolites were quantitated relative to water signal. For each location, an additional non-water-suppressed reference scan in fully relaxed conditions was performed. The imaging findings were divided into four categories: I, normal; II, edema only; III, contrast-enhancing lesions; and IV, cystic encephalomalacia. The N-acetyl-aspartate levels were reduced in 27 (96%) spectra. Choline was increased in 3 (11%), normal in 4 (14%), and reduced in 21 (75%) spectra. The creatine level was normal in 8 (29%) spectra and reduced in 20 (71%) spectra. Imaging showed 4 (14%) spectra with category-I imaging findings; 5 (18%) spectra with category-II findings; 15 (54%) spectra with category-III findings; and 4 (14%) spectra with category-IV findings. Magnetic resonance spectroscopy showed reduced N-acetyl-aspartate in radiation-induced temporal lobe changes. Creatine levels were relatively more stable. Choline levels may be increased, normal, or reduced. Imaging findings ranged from normal to contrast-enhancing lesions and cystic encephalomalacia.

Diagnostic and prognostic value of cerebral 31P magnetic resonance spectroscopy in neonates with perinatal asphyxia.

The impact of depressed neonatal cerebral oxidative phosphorylation for diagnosing the severity of perinatal asphyxia was estimated by correlating the concentrations of phosphocreatine (PCr) and ATP as determined by magnetic resonance spectroscopy with the degree of hypoxic-ischemic encephalopathy (HIE) in 23 asphyxiated term neonates. Ten healthy age-matched neonates served as controls. In patients, the mean concentrations +/- SD of PCr and ATP were 0.99 +/- 0.46 mmol/L (1.6 +/- 0.2 mmol/L) and 0.99 +/- 0.35 mmol/L (1.7 +/- 0.2 mmol/L), respectively (normal values in parentheses). [PCr] and [ATP] correlated significantly with the severity of HIE (r = 0.85 and 0.9, respectively, p < 0.001), indicating that the neonatal encephalopathy is the clinical manifestation of a marred brain energy metabolism. Neurodevelopmental outcome was evaluated in 21 children at 3, 9, and 18 mo. Seven infants had multiple impairments, five were moderately handicapped, five had only mild symptoms, and four were normal. There was a significant correlation between the cerebral concentrations of PCr or ATP at birth and outcome (r = 0.8, p < 0.001) and between the degree of neonatal neurologic depression and outcome (r = 0.7). More important, the outcome of neonates with moderate HIE could better be predicted with information from quantitative 31P magnetic resonance spectroscopy than from neurologic examinations. In general, the accuracy of outcome predictability could significantly be increased by adding results from 31P magnetic resonance spectroscopy to the neonatal neurologic score, but not vice versa. No correlation with outcome was found for other perinatal risk factors, including Apgar score.

Correlation of the apparent diffusion coefficient and the creatine level in early ischemic stroke: a comparison of different patterns by magnetic resonance.

It has been reported that reduction of the apparent diffusion coefficient (ADC) after stroke can persist for several days, after which the ADC increases gradually to an abnormally high level. We evaluated ADC values of stroke lesions and compared the results to the cellular density of the lesion by means of the creatine (Cre) level. This two-parameter estimation is of particular relevance in ascertaining the underlying cellular status. Lesion-to-contralateral ADC ratios (ADCn) were obtained based on diffusion-weighted echo-planar and fast spin-echo imaging. Single-voxel localized spectroscopy was used for quantification of cerebral metabolites in infarcted regions. Their levels were also compared to that in homotopic contralateral regions. Fifteen patients with ischemic stroke were examined at times ranging from 18-88 hours following the onset of symptoms. In the stroke lesion, there was a significant correlation between the ADC and the Cre level showing that the higher the cell density the lower the ADC value. For ADCn vs. the lesion Cre concentration and the lesion-to-contralateral Cre ratio (Cre(n)), the strengths of relationship were R2 = 0.70 and 0.58, respectively. It is concluded that ADC is a good reflection of cell density. Greatly lowered ADC values occur within the context of a stable cellularity. ADC and the Cre level have complementary roles in the characterization of stroke lesion with regard to the sequential stage.