Value of increased MRI signal intensity in cervical arthrosis in myelopathies

The case of 52 patients with cervical myelopathy were reviewed to determine whether a high signal intensity lesion present on T2 weighted spin echo imaging appears to be an important indicator for predicting prognosis. Preoperatively, there were areas of increased signal intensity in 23 patients. The lesion was clearly demonstrated on T1 weighted images in only one case. Postoperatively, MRI was performed in 9 cases, one showed decreased signal intensity compared to the preoperative levels, and 8 had no change. The pre and postoperative clinical conditions of the patients whose preoperative MR images showed areas of increase signal intensity were not worse than those patients who did not have these areas of increased signal intensity. The postoperative recovery of the eight patients who exhibited no change of the signal intensity was very satisfactory. The pathophysiology of such an abnormality is presumed to be related to edema, myelomalacia or gliosis. However, the presence of these areas of high signal intensity does not appear to be an indicator of a bad clinical prognosis.     

MR of hypoxic encephalopathy in children after near drowning: correlation with quantitative proton MR spectroscopy and clinical outcome

BACKGROUND AND PURPOSE: Quantitative MR spectroscopy has a proved role in the investigation of hypoxia caused by near drowning. To date, no studies have addressed the MR imaging changes that may also accompany this condition. The purpose of this study was to describe the MR imaging findings in children with hypoxic encephalopathy caused by near drowning and to compare these findings with the results of qualitative and quantitative proton MR spectroscopy and clinical outcome. METHODS: Twenty-two children (6 months to 11 years old) admitted to the pediatric intensive care unit after near drowning incidents underwent cerebral MR imaging and quantitative proton MR spectroscopy. Clinical and imaging studies were reviewed retrospectively, and subjects were grouped according to outcome: good result, persistent vegetative state, and death. Images were scored for edema, basal ganglia changes, and cortical changes, and were compared with MR spectra and outcome at days 1 to 2, 3 to 4, and 5 or more. RESULTS: Six patients had a good outcome, four remained in a persistent vegetative state, and 12 died. Generalized/occipital edema correlated with poor outcome. Indistinct lentiform nuclei margins on T1-weighted images were a frequent finding (78%). Basal ganglia T2 hyperintensity correlated with poor outcome, progressing from a patchy/peripheral distribution to diffuse high intensity. Patchy high T2 signal in the cortex or subcortical lines were specific but insensitive for poor outcome, as were brain stem infarcts. CONCLUSION: MR images in children with hypoxic encephalopathy after near drowning show a spectrum of changes. The most sensitive prognostic result may be achieved by combining MR imaging with qualitative and quantitative MR spectroscopic data.     

Total creatine in muscle: imaging and quantification with proton MR spectroscopy

Liver cell volume and intracellular ion concentrations are maintained within a narrow physiologic range by regulated changes in membrane ion permeability. These studies of homozygous HTC hepatoma cells, a model liver cell line, evaluate the relationship between cell volume and membrane ion permeability, and assess the possibility that cell swelling allows the efflux of the intracellular osmolite taurine through the opening of a conductive pathway. Cell swelling induced by exposure to hypotonic solutions (203 mOsm) caused a rapid increase in cell volume, followed by recovery toward basal values. Volume recovery was inhibited by Cl- depletion or by exposure to the putative Cl- channel blocker 5-nitro-2-(3-phenylpropyl-amino) benzoic acid (NPPB) (25 micromol/L). Swelling increased the efflux rates of 36Cl (181% +/- 15%, P < .01) and 125I (310% +/- 21%, P < .01). In whole cell patch clamp recordings, cell swelling induced by 1) exposure to hypotonic solution or 2) intracellular perfusion with hypertonic sucrose-containing solutions activated an anion-selective current which was outwardly rectified and showed time-dependent inactivation at depolarizing potentials. The current density at -80 mV increased proportionally with increases in the transmembrane osmotic gradient from basal values of -1 pA/pF to maximal values of 70 pA/pF with 100 mmol/L sucrose in the pipette. Basal taurine permeability was low, but cell swelling increased the efflux of [1,2-3H]taurine to 1,587% +/- 172% of basal levels (P < .05). Intracellular perfusion with hypertonic solutions activated currents carried by anionic taurine, with an estimated taurine/Cl- permeability ratio of .88 +/- .17 for whole cell currents. These studies demonstrate that the HTC membrane anion permeability is closely coupled to changes in cell volume, and that the recovery from swelling depends upon activation of anion-selective conductance pathways permeable to both Cl- and taurine.     

Human brain tumors: assessment with in vivo proton MR spectroscopy

To better understand variations in spectra of brain tumors, 122 in vivo proton spectra of brain tumors in 82 patients were analyzed. The changes in relative metabolite concentrations compared with those in normal spectra and the presence of any new metabolite were assessed. To evaluate the clinical usefulness of in vivo hydrogen-1 magnetic resonance (MR) spectroscopy in brain tumors, the authors looked for specific spectral changes on the basis of tumor grade. All tumor spectra showed differences from normal reference spectra. The differential diagnosis of the spectra was limited because intraindividual differences between spectra of one tumor at different locations were often larger than differences between spectra of tumors with different histologic characteristics. However, the variations in metabolite concentrations, and especially the presence or absence of aliphatic signals, were proved to be indicators of the histologic grade of tumor. The observed spectral patterns conformed to a four-compartment model, described herein, which is proposed to improve the interpretation of brain spectra.     

Traction injuries of the brachial plexus: signal intensity changes of the posterior cervical paraspinal muscles on MRI

PURPOSE: Our goal was to evaluate MR signal intensity change of the posterior cervical paraspinal muscles in brachial plexus traction injuries to determine the value of this finding in the diagnosis of nerve root avulsion. METHOD: MR images of 11 consecutive patients, 7 with nerve root avulsion and 4 without nerve root avulsion, were retrospectively analyzed, focusing on the signal intensity of the paraspinal muscles. RESULTS: Among the seven patients with nerve root avulsion, T2- or T2*-weighted MR images showed increased signal intensity in the deep posterior paraspinal muscles in five and traumatic meningocele in four. The signal intensity of the posterior paraspinal muscles was normal in all patients without nerve root injuries. CONCLUSION: MR signal intensity change in the deep posterior cervical paraspinal muscles is related to denervation and suggests the presence of nerve root avulsion.     

ILAE-defined epilepsy syndromes in children: correlation with quantitative MRI

PURPOSE: The role of quantitative magnetic resonance imaging (MRI) in evaluation of childhood epilepsy remains poorly defined, with minimal published data. Previous work from our center questioned the specificity of hippocampal asymmetry (HA) in an outpatient group whose epilepsy was defined by using clinical and interictal data only. By using childhood volunteer controls and defining epilepsy syndromes using video-EEG monitoring, we readdressed the utility of HA in differentiating mesial temporal lobe epilepsy (MTLE) from other partial and generalized epileptic syndromes in children. METHODS: Seventy children were enrolled; entry criteria were age younger than 18 years with predominant seizure type recorded on video-EEG telemetry with volumetric MRI in all cases. Thirty healthy child volunteers had volumetric MRI. Epilepsy syndrome classification was according to ILAE. RESULTS: Control data revealed symmetric hippocampi, mean smaller/larger ratio of 0.96 (0.95-0.97, 95% CI) with no gender or right/left predominance. Overall 23% of patients had significant HA. Mean hippocampal ratio for MTLE was 0.78 (95% CI, 0.70-0.86), significantly lower than controls and from all other epilepsy syndromes. HA was highly specific (85%) to the syndrome of MTLE. Other potential epileptogenic lesions were found in 27 (39%) patients, lowest yield in frontal and mesial temporal syndromes. Dual pathology was present in 10% of patients. There was no significant association between HA and risk factors. CONCLUSIONS: In this study, we found that HA in children with a well-defined epilepsy syndrome is highly sensitive and specific for MTLE. Whether this will correlate with surgical outcome, as in adults, is the subject of ongoing study.     

Absolute metabolite quantification by in vivo NMR spectroscopy: II. A multicentre trial of protocols for in vivo localised proton studies of human brain

We have performed a multicentre trial to assess the performance of three techniques for absolute quantification of cerebral metabolites using in vivo proton nuclear magnetic resonance (NMR). The techniques included were 1) an internal water standard method, 2) an external standard method based on phantom replacement, and 3) a more sophisticated method incorporating elements of both the internal and external standard approaches, together with compartmental analysis of brain water. Only the internal water standard technique could be readily implemented at all participating sites and gave acceptable precision and interlaboratory reproducibility. This method was insensitive to many of the experimental factors affecting the performance of the alternative techniques, including effects related to loading, standing waves and B1 inhomogeneities; and practical issues of phantom positioning, user expertise and examination duration. However, the internal water standard method assumes a value for the concentration of NMR-visible water within the spectroscopic volume of interest. In general, it is necessary to modify this assumed concentration on the basis of the grey matter, white matter and cerebrospinal fluid (CSF) content of the volume, and the NMR-visible water content of the grey and white matter fractions. Combining data from 11 sites, the concentrations of the principal NMR-visible metabolites in the brains of healthy subjects (age range 20-35 years) determined using the internal water standard method were (mean+/-SD): [NAA]=10.0+/-3.4 mM (n=53), [tCho]=1.9+/-1.0 mM (n=51), [Cr + PCr]=6.5+/-3.7 mM (n=51). Evidence of system instability and other sources of error at some participating sites reinforces the need for rigorous quality assurance in quantitative spectroscopy.     

High signal intensity of globus pallidus on T1-weighted MRI in liver cirrhosis patients: clinical and pathological study

In some patients with liver cirrhosis, the globus pallidus shows high signal intensity on T1-weighted MRI. The relationship was examined between high signal intensity on T1-weighted images and pathological conditions such as liver function, portal venous pressure and metal concentrations in brain. The signal of the globus pallidus on T1-weighted imaging became highly enhanced in accordance with prolongation of prothrombin time, deterioration of ICG R15, or decrease in choline esterase and the Fisher ratio. Furthermore, the high signal intensity was also seen in patients with high portal pressure and large varices. In histopathological study, remarkable atrophy and loss of nerve cells were observed in globus pallidus with high signal intensity on T1-weighted imaging, changes that were similar to those in with patients with manganese poisoning. The manganese concentration in autopsied globus pallidus with high signal intensity on T1-weighted imaging showed a 9.5-fold increase compared with that with normal intensity. In conclusion, the deposition of manganese in the globus pallidus, which is accompanied with the nerve cell deciduation, brings about the high signal intensity of the globus pallidus on T1-weighted MRI in patients with liver cirrhosis.     

A proton magnetic resonance spectroscopic study in ALS: correlation with clinical findings

OBJECTIVE: To evaluate neuronal dysfunction in the motor region subcortical white matter in ALS using volumetric localized proton magnetic resonance spectroscopy (1H-MRS). METHODS: Sixteen patients with E1 Escorial definite, probable, or possible ALS and eight healthy age-matched control subjects were studied. The ALS patients were divided into those with limb onset (n = 8) and those with bulbar onset (n = 8). Measurements of the metabolic ratios N-acetylaspartate (NAA)/creatine and phosphocreatine (Cr+PCr), NAA/choline (Cho), and Cho/(Cr+PCr) were correlated with clinical assessments. RESULTS: We found no differences in the metabolic peak area ratios in the motor region when comparing the total ALS group and the control subjects. However, correlations were found between the NAA/(Cr+PCr) ratio and the E1 Escorial category (p = 0.03), the ALS severity scale (p = 0.01), and the Medical Research Council score (p = 0.06). No correlations were found between the NAA/(Cr+PCr) ratio and the Ashworth Spasticity Scale, reflex score, or disease duration (p > 0.16). Bulbar-onset patients had a lower NAA/(Cr+PCr) ratio in the motor region compared with limb-onset patients (p = 0.03). CONCLUSION: In vivo 1H-MRS of the subcortical white matter in the motor region is unlikely to be sensitive enough to detect early disease changes in ALS because there is considerable overlap between the metabolic peak area ratios from patients with ALS and normal control subjects. However, changes in the NAA/(Cr+PCr) metabolic peak area ratios correlate with clinical measures of disease severity, and this measure may be useful in monitoring disease progression.     

Neurometabolism of active neuropsychiatric lupus determined with proton MR spectroscopy

PURPOSE: To determine the neurometabolism of patients with active neuropsychiatric systemic lupus erythematosus (NPSLE) by using proton MR spectroscopy. METHODS: Thirty-six patients with SLE and eight control subjects were studied with proton MR spectroscopy to measure brain metabolites. Peaks from N-acetylaspartate (NAA), creatine (Cr), choline (Cho), and at 1.3 parts per million (ppm) lipid, macromolecules, and lactate were measured. Patients were classified as having major NPSLE (seizures, psychosis, major cognitive dysfunction, delirium, stroke, or coma) (n = 15) or minor NPSLE (headache, minor affective disorder, or minor cognitive disorder) (n = 21). Patients with major NPSLE were severely ill and hospitalized. RESULTS: SLE patients had lower NAA and increased metabolites at 1.3 ppm than did control subjects (NAA/Cr(SLE) = 1.90 +/- 0.35, NAA/Cr(Control) = 2.16 +/- 0.26; 1.3 ppm/Cr(SLE) = 0.49 +/- 0.41, 1.3 ppm/Cr(Control) = 0.27 +/- 0.05). NAA/Cr in patients with current or prior major NPSLE was lower than in patients without major NPSLE. Increased peaks at 1.3 ppm were present in all SLE subgroups, but particularly in patients with major NPSLE. These resonances were not evident at an echo time of 136, indicating that these signals were not lactate. CONCLUSION: Major NPSLE, past or present, is associated with decreased levels of NAA. Elevated peaks around 1.3 ppm do not represent lactate even in severely ill patients, indicating that global ischemia is not characteristic of NPSLE. Neurochemical markers determined by MR spectroscopy may be useful for determining activity and degree of brain injury in NPSLE.     

Diffusion-weighted MRI in transient global amnesia: elevated signal intensity in the left mesial temporal lobe in 7 of 10 patients

Selective decontamination of the digestive tract (SDD) has been widely studied in the intensive care setting. Despite the publication of more than 50 controlled trials, it remains a controversial subject, with widely disparate views on the role of SDD. This article reviews the use of SDD primarily by examining the areas of controversy. The published data seem to show clear evidence that SDD can reduce acquired infection during intensive care. Most individual studies have shown no effect on mortality, but meta-analyses suggest a 10% overall reduction in mortality. Despite the large number of publications to date, there remain several aspects worthy of further study.     

Sequential observations of brain edema with proton magnetic resonance imaging and spectroscopy

The purpose of this study was to assess the relationship between morphological and metabolic changes in brain edema using proton magnetic resonance systems. The serial changes during the first 24 hours in the cold-injury trauma rat brain model were investigated by proton magnetic resonance imaging (1H MRI) and high-resolution proton MR spectroscopy (1H MRS). We also analyzed the efficacy of AVS 1,2-bis (nicotinamide)-propane which can scavenge free radicals to the edema in this experiment. The edema was developing extensively via the corpus callosum in ipsi- and contralateral hemispheres as shown by gradually increased signal intensity on 1H MRI. 1H MRS initially showed accumulation of acetate and lactate, and transient increasing of glutamine. After 24 hours, the increased glutamine decreased below the control, alanine increased, and N-acetyl asparatate decreased with the edema development. AVS-treatment significantly suppressed edema development, increases of lactate and alanine and decreases of N-acetyl asparatate. We suggest that the cold-induced lesion contains anaerobic glycolysis deterioration and results in severe brain tissue breakdown. AVS is proved valuable for the treatment of this edema lesion. Clinical 1H MRS showed prolonged lactate elevation and significant decreases of other metabolites in human ischemic stroke edema. In peritumoral edema, decreased N-acetyl asparatate gradually improved, and slightly elevated lactate disappeared after tumor removal. 1H MRS feasibly characterizes the ischemic and peritumoral edema and makes a quantitative analysis in human brain metabolism. We believe the combined 1H MRI and MRS study is a practical method to monitor the brain conditions and will make it easy and possible to find new therapeutic agents to some brain disorders.     

Central poststroke pain: correlation of MRI with clinical pain characteristics and sensory abnormalities

OBJECTIVE: To correlate MRI and sensory changes in patients with spontaneous lesions in the cerebral "pain pathway." METHODS: The authors used MRI and quantitative somatosensory testing in 73 patients with central poststroke pain (CPSP) and in 13 patients with pain-free stroke with sensory deficit. RESULTS: Lesions in any part of the discriminatory somatosensory pathway may or may not produce CPSP. Most CPSP patients have multiple lesions, many probably unrelated to pain. Ventroposterior thalamic nuclear lesions are more likely to produce half-body pain than lesions elsewhere (including the brainstem). In supratentorial lesions, the greatest pain is more likely to be in an extremity, and in infratentorial lesions, the greatest pain is likely to be in the face. Supratentorial CPSP patients have a deficit of sharpness and cold (peripherally mediated by A delta fibers) than pain-free stroke patients, whereas patients with infratentorial CPSP additionally have a deficit of C-fiber-mediated warmth and hot pain. Burning pain is more common than nonburning pain in younger patients. Warmth and cold, but not hot pain, exhibiting central convergence (spatial summation) are more affected in CPSP patients with burning than nonburning pain. Allodynic CPSP patients had a significantly greater deficit for warmth than patients without allodynia. CONCLUSIONS: Different stroke sites produce different patterns of sensory deficit. The progression from painless sensory deficit to CPSP is not purely quantitative.     

Thrombosis of the deep cerebral veins: CT and MRI findings with pathologic correlation

Deep cerebral vein thrombosis can present with acute, severe neurological symptoms and may be rapidly fatal as in the 20-year-old woman reported here. Although MRI is superior for establishing the diagnosis, CT is usually the first examination performed in the clinical setting. It is therefore important to recognise certain indicators such as extensive bithalamic low density. These and certain other less specific signs are correlated with the MRI and autopsy findings.     

Brain alcohol detectability increase with repeated administration in humans: a proton spectroscopy study

BACKGROUND AND PURPOSE: There is evidence that an allelic variation in the angiotensin-converting enzyme (ACE) gene may confer an increased risk of vascular disease. The roles of the ACE insertion/deletion polymorphism and circulating ACE levels are unknown in cerebrovascular disease. METHODS: We studied an insertion/deletion polymorphism within intron 16 of the ACE gene by polymerase chain reaction and plasma ACE activity in 467 cases of stroke, the pathological type of which was established by cranial CT, and 231 control subjects. ACE genotype and activity were related to stroke type and mortality at 4 weeks and 3 months. RESULTS: No difference in genotype frequency was observed between all subjects with stroke and control subjects or between control subjects and subjects with cerebral infarction or cerebral hemorrhage. Plasma ACE activity was significantly lower in stroke patients at presentation (64.1 IU/L) than in control subjects (79.6 IU/L; P<.0001). Twenty-one patients (4.5%) with cerebral infarction died within 4 weeks and 56 patients (12%) within 3 months. These patients had significantly lower plasma ACE activity than patients who survived. There was some evidence that risk of death within 4 weeks increased with the number of D alleles (P=.02). Among survivors, plasma ACE activity showed a mean increase of 6.9 IU/L (95% confidence interval, 3.0 to 10.8) between levels at presentation and at 3 months (73.6 IU/L), the latter being similar to ACE activity in control subjects. CONCLUSIONS: Low ACE activity at sroke presentation and possession of the D allele may be associated with increased risk of early death from acute cerebral infarction.     

The patellar tilt angle: correlation of MRI evaluation with anterior knee pain

The purpose of this study was to analyze the degree of patella tilt and its correlation with the symptoms of anterior knee pain. We used magnetic resonance imaging (MRI) to measure the angle of patella tilt. The patients (n = 128) were classified into two groups. Group 1 (n = 78) included patients who had never had symptoms of anterior knee pain but had MRI for evaluation of the menisci and the ligaments. Group 2 (n = 50) included patients who had MRI for evaluation of anterior knee pain syndrome. Patients who had gross deformities like patellar dislocation, tricompartmental osteoarthritis, or inflammatory arthritis were excluded. The average patella tilt angle was 6.3 (SD = 3.9) and 12.8 (SD = 8.4) degrees, respectively, for the two groups of patients. Twenty-three patients in group 2 underwent arthroscopy because of failure of conservative treatment, and the average patella tilt angle in this subgroup was 16.4 degrees. Our study suggests that patella tilt angle is correlated with the symptoms of anterior knee pain, and indicated that the cause of pain came from the tight lateral retinaculum. In addition, MRI was found to be an accurate and reproducible method of measurement of the patellar tilt angle.     

CT and MRI of the male genital tract: radiologic-pathologic correlation

Technical advances in magnetic resonance imaging (MRI), notably in high-resolution MRI, have opened up new diagnostic applications in male pelvic pathology. A major indication is the preoperative staging of prostate cancer, where MRI is more reliable than other imaging modalities in differentiating between localized and advanced disease. In monitoring local recurrence after radical prostatectomy MRI is also valuable in differentiating scar tissue from new growth. In benign prostate disease, MRI effectively displays the congenital cysts that may be associated with infertility. Other disease, however - notably benign prostatic hyperplasia - is generally an incidental finding. Ultrasound remains the imaging modality of choice for evaluation of pathologies of the penis, testis and scrotum, e. g. in differentiating malignant from benign scrotal masses or in diagnosing acute scrotum due to testicular torsion or rupture. In isolated cases, MRI is also a valuable diagnostic aid in conditions of these organs, e. g. in the preoperative localization of ectopic testes in cryptorchidism or if US findings are equivocal.     

Technetium-99m-DTPA-galactosyl human serum albumin liver scintigraphy evaluation of regional CT/MRI attenuation/signal intensity differences

Terbinafine is an allylamine antifungal agent widely used to treat dermatophyte onychomycosis and dermatomycoses. We report 10 severe cutaneous adverse reactions associated with terbinafine therapy which required discontinuation of the antifungal agent: erythema multiforme (five patients), erythroderma (one), severe urticaria (one), pityriasis rosea (one) and worsening of pre-existing psoriasis (two patients). The spectrum of cutaneous adverse effects associated with terbinafine therapy is reviewed. Patients should be counselled about discontinuing terbinafine at the onset of a cutaneous eruption and about seeking medical advice about further management.