Multitrait genome association analysis identifies new susceptibility genes for human anthropometric variation in the GCAT cohort

Background

Heritability estimates have revealed an important contribution of SNP variants for most common traits; however, SNP analysis by single-trait genome-wide association studies (GWAS) has failed to uncover their impact. In this study, we applied a multitrait GWAS approach to discover additional factor of the missing heritability of human anthropometric variation.

Methods

We analysed 205 traits, including diseases identified at baseline in the GCAT cohort (Genomes For Life- Cohort study of the Genomes of Catalonia) (n=4988), a Mediterranean adult population-based cohort study from the south of Europe. We estimated SNP heritability contribution and single-trait GWAS for all traits from 15 million SNP variants. Then, we applied a multitrait-related approach to study genome-wide association to anthropometric measures in a two-stage meta-analysis with the UK Biobank cohort (n=336 107).

Results

Heritability estimates (eg, skin colour, alcohol consumption, smoking habit, body mass index, educational level or height) revealed an important contribution of SNP variants, ranging from 18% to 77%. Single-trait analysis identified 1785 SNPs with genome-wide significance threshold. From these, several previously reported single-trait hits were confirmed in our sample with LINC01432 (p=1.9×10⁻⁹) variants associated with male baldness, LDLR variants with hyperlipidaemia (ICD-9:272) (p=9.4×10⁻¹⁰) and variants in IRF4 (p=2.8×10⁻⁵⁷), SLC45A2 (p=2.2×10⁻¹³⁰), HERC2 (p=2.8×10⁻¹⁷⁶), OCA2 (p=2.4×10⁻¹²¹) and MC1R (p=7.7×10⁻²²) associated with hair, eye and skin colour, freckling, tanning capacity and sun burning sensitivity and the Fitzpatrick phototype score, all highly correlated cross-phenotypes. Multitrait meta-analysis of anthropometric variation validated 27 loci in a two-stage meta-analysis with a large British ancestry cohort, six of which are newly reported here (p value threshold <5×10⁻⁹) at ZRANB2-AS2, PIK3R1, EPHA7, MAD1L1, CACUL1 and MAP3K9.

Conclusion

Considering multiple-related genetic phenotypes improve associated genome signal detection. These results indicate the potential value of data-driven multivariate phenotyping for genetic studies in large population-based cohorts to contribute to knowledge of complex traits.

Decreased lipid metabolism but increased FA biosynthesis are coupled with changes in liver microRNAs in obese subjects with NAFLD

BACKGROUND/OBJECTIVE

Many controversies regarding the association of liver miRNAs with obesity and nonalcoholic fatty liver diseases (NAFLD) call for additional validations. This study sought to investigate variations in genes and hepatic miRNAs in a sample of obese patients with or without NAFLD and human hepatocytes (HH).

SUBJECTS/METHODS

A total of 60 non-consecutive obese women following bariatric surgery were recruited. Subjects were classified as NAFLD (n=17), borderline (n=24) and controls (n=19) with normal enzymatic profile, liver histology and ultrasound assessments. Profiling of 744 miRNAs was performed in 8 obese women with no sign of hepatic disease and 11 NAFLD patients. Additional validation and expression of genes related to de novo fatty acid (FA) biosynthesis, uptake, transport and β-oxidation; glucose metabolism, and inflammation was tested in the extended sample. Induction of NAFLD-related genes and miRNAs was examined in HepG2 cells and primary HH treated with palmitic acid (PA), a combination of palmitate and oleic acid, or high glucose, and insulin (HG) mimicking insulin resistance in NAFLD.

RESULTS

In the discovery sample, 14 miRNAs were associated with NAFLD. Analyses in the extended sample confirmed decreased miR-139-5p, miR-30b-5p, miR-122-5p and miR-422a, and increased miR-146b-5p in obese subjects with NAFLD. Multiple linear regression analyses disclosed that NAFLD contributed independently to explain miR-139-5p (P=0.005), miR-30b-5p (P=0.005), miR-122-5p (P=0.021), miR-422a (P=0.007) and miR-146a (P=0.033) expression variance after controlling for confounders. Decreased miR-122-5p in liver was associated with impaired FA usage. Expression of inflammatory and macrophage-related genes was opposite to decreased miR-30b-5p, miR-139-5p and miR-422a, whereas increased miR-146b-5p was associated with FABP4 and decreased glucose metabolism and FA mobilization. In partial agreement, PA (but not HG) led to decreased miR-139-5p, miR-30b-5p, miR-422a and miR-146a in vitro, in parallel with increased lipogenesis and FA transport, decreased glucose metabolism and diminished FA oxidation.

CONCLUSION

This study confirms decreased liver glucose and lipid metabolism but increased FA biosynthesis coupled with changes in five unique miRNAs in obese patients with NAFLD.

Altered brain-derived neurotrophic factor blood levels and gene variability are associated with anorexia and bulimia

Murine models and association studies in eating disorder (ED) patients have shown a role for the brain-derived neurotrophic factor (BDNF) in eating behavior. Some studies have shown association of BDNF -270C/T single-nucleotide polymorphism (SNP) with bulimia nervosa (BN), while BDNF Val66Met variant has been shown to be associated with both BN and anorexia nervosa (AN). To further test the role of this neurotrophin in humans, we screened 36 SNPs in the BDNF gene and tested for their association with ED and plasma BDNF levels as a quantitative trait. We performed a family-based association study in 106 ED nuclear families and analyzed BDNF blood levels in 110 ED patients and in 50 sib pairs discordant for ED. The rs7124442T/rs11030102C/rs11030119G haplotype was found associated with high BDNF levels (mean BDNF TCG haplotype carriers = 43.6 ng/ml vs. mean others 23.0 ng/ml, P = 0.016) and BN (Z = 2.64; P recessive = 0.008), and the rs7934165A/270T haplotype was associated with AN (Z =-2.64; P additive = 0.008). The comparison of BDNF levels in 50 ED discordant sib pairs showed elevated plasma BDNF levels for the ED group (mean controls = 41.0 vs. mean ED = 52.7; P = 0.004). Our data strongly suggest that altered BDNF levels modulated by BDNF gene variability are associated with the susceptibility to ED, providing physiological evidence that BDNF plays a role in the development of AN and BN, and strongly arguing for its involvement in eating behavior and body weight regulation.

Increased cerebral activity in Parkinson?s disease patients carrying the DRD2 TaqIA A1 allele during a demanding motor task: a compensatory mechanism?

Previous studies suggest that neuroimaging techniques are useful for detecting the effects of functional genetic polymorphisms on brain function in healthy subjects or in patients presenting with psychiatric or neurodegenerative conditions. Former evidence showed that individuals carrying risk alleles displayed broader patterns of brain activity during behavioural and cognitive tasks, despite being clinically comparable to non-carriers. This suggests the presence of compensatory brain mechanisms. In the present study, we investigated this effect in Parkinson's disease (PD) patients carrying the DRD2 TaqIA A1 allelic variant. This variant may confer an increased risk of developing the disease and/or influence the clinical presentation. During a complex sequential motor task, we evidenced by functional magnetic resonance imaging that A1 allele carriers activated a larger network of bilateral cerebral areas than non-carriers, including cerebellar and premotor regions. Both groups had similar clinical and demographic measures. In addition, their motor performance during the functional magnetic resonance experiment was comparable. Therefore, our conclusions, pending replication in a larger sample, seem to reflect the recruitment of compensatory cerebral resources during motor processing in PD patients carrying the A1 allele.

Abnormal orbitofrontal development due to prematurity

OBJECTIVE

To investigate the effects of prematurity on sulcal formation.

METHODS

We evaluated the depth and volume of the primary olfactory sulcus (developed at 16 weeks' gestation) and the secondary orbital sulci (which start to develop at 28 weeks' gestation) in a sample of 22 adolescents with history of very-preterm birth (VPTB). We compared this preterm sample with a sample of subjects born at term and matched by age, gender, and sociocultural status. The Anatomist/BrainVISA 3.0.1 package was used to identify and quantify the sulci. In addition, voxel-based morphometry (VBM) was used to analyze possible reductions of gray and white matter in the orbitofrontal area.

RESULTS

Compared with controls, we found a significant reduction in the secondary sulci depth but not in the primary sulcus in the VPTB. VBM analysis showed reduced gray-matter volume in VPTB in the orbital region.

CONCLUSIONS

Premature birth affects cerebral gyrification, and this impairment is not reversible during childhood. Identification of the specific factors involved in abnormal brain maturation may lead to effective interventions.

Cerebral correlates of declarative memory dysfunctions in early traumatic brain injury

We investigated residual brain damage in subjects who suffered severe traumatic brain injury (TBI) in childhood, and its relationship with declarative memory impairment. Magnetic resonance imaging (MRI) volumetric data and memory performance were compared between 16 adolescents with antecedents of severe TBI and 16 matched normal controls. Volumes of grey matter, white matter, cerebrospinal fluid (CSF), hippocampus, and caudate nuclei were measured. Verbal memory was assessed by the Rey's Auditory Verbal Learning test and visual memory by the Rey's Complex Figure. TBI patients performed significantly worse than controls in both verbal and visual memory. Patients presented decreased white matter volume and increased CSF. The hippocampus was reduced, but not the caudate nuclei. Memory performance correlated with CSF. Plasticity is incomplete for structural and functional deficits in children with TBI. Hippocampal atrophy, white matter loss, and memory impairment remain until adolescence. Memory sequelae are related more to diffuse brain injury, as reflected by MRI findings of increased CSF, than to hippocampal injury.

Apolipoproteins E and C1 and brain morphology in memory impaired elders

Previous research has shown that polymorphisms of the apolipoproteins E ( APOE) and APOC1 represent genetic risk factors for dementia and for cognitive impairment in the elderly. The brain mechanisms by which these genetic variations affect behavior or clinical severity are poorly understood. We studied the effect of APOE and APOC1 genes on magnetic resonance imaging measures in a sample of 50 subjects with age-associated memory impairment. The APOE E4 allele was associated with reduced left hippocampal volumes and APOE*E3 status was associated with greater frontal lobe white matter volumes. However, no APOE effects were observed when analyses accounted for other potential confounding variables. The effects of APOC1 on hippocampal volumes appeared to be more robust than those of the APOE polymorphism. However, no modulatory effects on brain morphology outside the medial temporal lobe region were observed when demographic variables, clinical status, and other anatomical brain measurements were taken into consideration. Our results suggest that the role of the APOC1 polymorphism in brain morphology of the cognitively impaired elderly should be examined in further studies.

(1)H-MR spectroscopy is sensitive to subtle effects of perinatal asphyxia

The authors performed neuropsychological and (1)H-MRS studies in 18 subclinical patients with antecedents of perinatal asphyxia (PA) and in 18 matched control subjects. Patients with PA showed reduced values of N-acetylaspartate (NAA) in both the basal ganglia and the midtemporal region (MTR) and reduced NAA/choline values in the MTR. Neuropsychological testing showed group differences in tasks related to attention and memory. These results indicate persistent dysfunctions in cerebral structures vulnerable to hypoxia and demonstrate the utility of MRS for the long-term evaluation of cerebral sequelae of neonatal asphyxia.

MRI and genetic correlates of cognitive function in elders with memory impairment

The present study investigated the relationship between genetic variation, MRI measurements and neuropsychological function in a sample of 58 elders exhibiting memory decline. In agreement with previous reports, we found that the epsilon4 allele of the apolipoprotein E (APOE) and the D allele of the angiotensin converting enzyme (ACE) polymorphisms negatively modulated the cognitive performance. Further, we found an association between the A allele of the apolipoprotein C1 (APOC1) polymorphism and poorer memory and frontal lobe function. No clear associations emerged between MRI measures of white matter lesions (WML) or hippocampal sulcal cavities (HSC) and the cognitive performance after controlling for age effects. Further, the degree of WML or HSC lesions was in general not predisposed genetically except for the presence of the A allele of the APOC1 polymorphism that was related to a higher severity of HSC scores. Our results suggest that WML or HSC do not represent important brain correlates of genetic influences on cognitive performance in memory impaired subjects.

[Study of the long term sequelae of traumatic brain injury: evaluation of declarative and procedural memory, and its neuroanatomic substrate]

INTRODUCTION AND OBJECTIVES

The hippocampus and the striatum have been proposed as respectively cerebral substrates of declarative and procedural memory. Both structures are vulnerable to traumatic brain injury. Although declarative and procedural memory have been reported to be impaired in traumatic brain injury (TBI), volumetric measures have so far failed to associate this impairment with atrophy of hippocampal and striatal structures. In our study, we investigated the profile of declarative and procedural memory in children who suffered from moderate to severe traumatic brain injury during childhood (injury test interval: 9.42+/-1.98 years).

PATIENTS AND METHODS

Nineteen patients and matched controls were evaluated on tests of declarative memory and motor learning. Results showed that TBI subjects exhibit poorer performance in both tasks. Moreover, structural magnetic resonance images were obtained from TBI subjects. In order to relate neuropsychological performance with hippocampal and neostriatal volumetric data, correlation analyses were performed.

RESULTS

Significant positive correlations were obtained between hippocampal volume and memory for objects. Striatal volume correlated positively with motor learning and with verbal memory.

CONCLUSIONS

It thus seems that plasticity does not completely compensate for the memory deficits resultant from neural loss in the immature brain.

Correlation of atrophy measures on MRI with neuropsychological sequelae in children and adolescents with traumatic brain injury

To examine the relationship between neuropsychological sequelae and atrophy parameters from magnetic resonance imaging (MRI) following paediatric moderate-to-severe traumatic brain injury (TBI), 19 head injured children and adolescents were studied at least 6 years after injury. Three-dimensional MRI scans were obtained. A semi-automatic computerized method was used to estimate ventricular volumes and the corpus callosum area. Tests of intellectual, memory, visuospatial, frontal lobe, and motor speed functioning were administered to all patients and to 19 matched normal control subjects. Patients' performance significantly differed from controls in general intellectual function, visual memory, visuospatial and frontal lobe tests. The corpus callosum area correlated strongly with several measures involving processing speed and visuospatial function. Ventricular enlargement was less related to neuropsychological outcome. In conclusion, quantitative measurement of the corpus callosum on MRI reflects neuropsychological outcome better than ventricular dilation in paediatric patients.

MRI atrophy parameters related to cognitive and motor impairment in Parkinson's disease

BACKGROUND

Patients with Parkinson's disease (PD) show specific neuropsychological deficits in attention, memory, visuospatial or frontal lobe functions, which can arise from degeneration of different cerebral structures.

OBJECTIVE

The aim of the present study was to analyze the role of focal degeneration (basal ganglia and substantia nigra) and diffuse cerebral atrophy (ventricular enlargement) in motor/cognitive impairment in PD.

PATIENTS AND METHODS

We administered to 14 patients with advanced PD the following tests: Purdue Pegboard, Rey's Auditory-Verbal Learning test (RAVLT), Benton's Line Orientation, Trail Making, phonemic verbal fluency and Stroop test. Ventricular system, caudate and putamen nuclei and pars compacta of the substantia nigra were quantitatively measured by magnetic resonance imaging. Correlation analyses were carried out.

RESULTS

The results showed that ventricular enlargement is negatively correlated with the performance on RAVLT and Stroop test. No relationship was found between caudate atrophy and cognitive deficits. Degeneration of putamen nucleus was found to be associated with motor deficits.

CONCLUSION

Memory and frontal impairment are related to diffuse cerebral degeneration and the motor deficit is related to degeneration of the putamen nucleus.

Neuroradiological and clinical findings in rhombencephalosynapsis

Rhombencephalosynapsis is an unusual disorder characterised by maldevelopment of the rhombencephalon, sometimes with supratentorial midline anomalies. We report MRI findings in a 39-year-old woman, the oldest in the literature. MRI demonstrated hypoplasia of the cerebellar vermis, with fusion of the cerebellar hemispheres and abnormally oriented folia. Supratentorial anomalies were also seen.

Cortical laminar necrosis caused by immunosuppressive therapy and chemotherapy

We report three patients in whom neurologic symptoms and cortical laminar necrosis developed after immunosuppressive treatment (cyclosporin A and FK 506) and polychemotherapy (vincristine and methotrexate). Initial neuroradiologic studies showed cortical and white matter involvement. Follow-up studies showed cortical hyper-intense lesions on T1-weighted MR images, consistent with cortical laminar necrosis. The clinical and radiologic data indicate that a transient hypoxic-ischemic process could have been responsible for the encephalic lesions in these three patients.

[Application of magnetic resonance spectroscopy in the study of brain disease]

INTRODUCTION AND OBJECTIVE

Magnetic resonance spectroscopy (MRS) is a non-invasive technique used for the neurochemical study of the brain in vivo. The aim of this work is to review the main investigations that have focused on the study of cerebral pathology.

DEVELOPMENT

Cerebral MRS studies started in 1983 but the maximum development has been in the 90's. The pathologies more investigated were Alzheimer's disease, multiple sclerosis, schizophrenia, and depression. Although several nuclei can be observed the most investigated are phosphor (P31) and hydrogen (H1). Nowadays proton MRS is the more frequently used technique. The low levels of N-acetyl-aspartate are a good indicator of neuronal loss. Their determination is complementary to the volumetric structural studies from magnetic resonance imaging. The peak of myo-inositol seems to be a neurochemical marker for the Alzheimer's disease.

CONCLUSIONS

MRS have contributed to the increase of knowledge about the physiopathology of normal aging, degenerative processes, demyelinating and psychiatric diseases. Potentially can contribute to differential diagnose in Alzheimer's and Parkinson's diseases. Recently it has also been opened a new research potential in the field of the pharmacological treatment effects in discrete cerebral regions.

Cognitive and behavioral changes after unilateral posteroventral pallidotomy: relationship with lesional data from MRI

We investigated cognitive and behavioral changes after unilateral posteroventral pallidotomy, and their relationship with lesion size and location as identified in magnetic resonance image quantitative analysis. Fifteen consecutive patients with Parkinson's disease were assessed neuropsychologically before and after unilateral posteroventral pallidotomy (five right and 10 left). Immediate postsurgery evaluation (1 week) demonstrated significant worsening of memory, motor learning, motor speed, and verbal fluency. In the 3-month follow up, learning, memory, and speed returned to the presurgical level, but verbal fluency remained below the baseline. Significant improvements were observed in visuospatial functions and obsessive-compulsive behavior. Lesional volume did not correlate with neuropsychologic changes. Left lesions produced more impairment in verbal fluency than right-sided lesions. Regression analysis identified two lesional areas in the pallidum mediale internum. These regions accounted for 68% of the variance in the visuospatial changes.

Magnetic resonance imaging in myelofibrosis and essential thrombocythaemia: contribution to differential diagnosis

To ascertain the value of magnetic resonance (MR) imaging in the differential diagnosis between myelofibrosis (MF) and essential thrombocythaemia (ET), 38 patients were analysed. 20 patients had MF (idiopathic myelofibrosis, 15 cases; post-ET myelofibrosis, four cases; post-polycythaemic MF, one case) and 18 ET. Mean age was 61.5 years (range 30-89) for patients with MF and 60.9 years (range 26-83) for ET patients. MR imaging was performed in the dorsal vertebrae in all cases, and also in both femurs in 2 5 of the patients. In most ET cases the MR signal of the dorsal vertebrae was not modified, whereas it was markedly reduced in MF (P=0.0000001). With regard to femoral marrow, it was usually fatty in ET, with an absent to moderate degree of reconversion seen in the 14 cases analysed, contrasting with the marked degree of reconversion noted in 10/11 patients with MF (P=0.000007). An inverse correlation was demonstrated between the vertebral signal and the degree of femoral reconversion. These differences were due to the fact that in ET the bone marrow adipose tissue is grossly preserved, whereas in MF it is usually markedly decreased or absent. The above results indicate that MR imaging is a useful tool for the differential diagnosis of ET and MF, with the usefulness of this technique increasing when vertebral and femoral bone marrow studies are combined.

[Contribution of magnetic resonance to the differential diagnosis of a collapsed vertebra in a patient with multiple myeloma]

The only safe method to determine whether or not patients diagnosed of smoldering myeloma will progress to symptomatic multiple myeloma (MM) is periodic follow-up. In the last years, several studies have emphasized the efficacy of magnetic resonance imaging (MRI) to detect bone marrow involvement in these patients. However, the detection of a focal spinal lesion in elderly patients raises a diagnostic problem, sometimes difficult to solve, between a benign or malignant origin. We present the case of an elderly women with marked osteoporosis and smoldering myeloma who suddenly complained of pain in dorsal spine. MRI showed focal lesions in two dorsal vertebra consistent with myeloma involvement. However, there were no other signs of progression, the lesions were considered secondary to osteoporosis and calcitonin was administered. This resulted in the disappearance of the pain and the MRI abnormalities, which confirmed its benign etiology. The role and limitations of MRI to detect bone marrow involvement by MM in the evaluation of these patients is reviewed.

Hepatoerythropoietic porphyria: neuroimaging findings

CT and MR findings in two patients with hepatoerythropoietic porphyria are presented. CT scans showed atrophy and cortical mineralization at the same level. MR examination performed in one of the two patients showed mainly frontal cortical atrophy and punctate bright signal on T1- and T2-weighted sequences.

Estimation of bone marrow cellularity by means of vertebral magnetic resonance

BACKGROUND AND OBJECTIVE

A magnetic resonance (MR) signal shows an inverse correlation with bone marrow cellularity. In this study, we investigated the possibility of estimating the degree of bone marrow cellularity by means of this non-invasive technique.

METHODS

In 25 patients with different hematological disorders and homogeneous bone marrow distribution, the percentage of bone marrow cellularity was compared to the MR signal of four middorsal vertebrae in T1 sequence. As internal control, the MR signal of the mid-dorsal spinal cord region was used. The results were expressed as the MR signal ratio (great mean MR signal of four vertebrae/MR signal of the spinal cord).

RESULTS

The correlation coefficient (r) between both parameters was -0.93 (p < 0.0001). All observed values fell within the 90% limits of predicted values. The mean difference between observed and predicted bone marrow cellularity was 5.6 (SD 4.0)%.

INTERPRETATION AND CONCLUSIONS

The measurement of the MR signal is not easy to standardize since it depends to a large degree on the control employed. The spinal cord proved to be a satisfactory internal control of the MR signal. Within defined conditions, MR can be useful for a rough estimate of bone marrow cellularity in several clinical situations, such as analysis of tumor burden for prognosis of some leukemias and the evaluation of response to therapy in both proliferative and hypoplastic disorders.

The "target sign": is it a specific sign of CNS tuberculoma?

In brain lesions, the target sign has been defined as a central nidus of calcification or central enhancement surrounded by a ring of enhancement. It has been considered a pathognomonic finding of central nervous system (CNS) tuberculoma. The purpose of this report is to demonstrate that the target sign related to central enhancement is a nonspecific finding and may lead to erroneous diagnosis of CNS tuberculoma.

[Occult involvement of bone marrow in Hodgkin's disease: detection with magnetic resonance]

Although bone marrow biopsy is considered the best procedure to detect bone marrow involvement by Hodgkin's disease (HD), in recent years several studies have emphasized the value of magnetic resonance imaging (MRI). We present the case of a patient with HD apparently localized in a laterocervical lymph node, who also referred disestasiae at a region corresponding to D10 metamera. Bone marrow biopsy, vertebral TC and 67-Ga scintigraphy were all normal. However, a node of 1 cm in diameter was detected by MRI in the tenth dorsal vertebra. Because of the topographic coincidence between the patient's symptomatology and the MRI findings, the HD was considered to be in advanced stage and CMOPP/ABV chemotherapy was administered, this resulting in a rapid improvement of symptoms and disappearance of the MRI abnormalities. Since in the present case, the MRI determined a change in disease stage and treatment, the role of MRI as a complementary exploration of bone marrow biopsy to detect marrow involvement by HD is reviewed.

[Magnetic resonance of the spinal cord: a densitometric analysis]

BACKGROUND

Images obtained by magnetic resonance can present changes in a variety of haematologic disorders. The vertebral magnetic resonance signal depends chiefly on the relationship between fatty and cellular components of the haemopoietic bone marrow. A quantitative analysis of signal can be performed either during the magnetic resonance examination or on the computer-stored images. In this work, a densitometric grey-scale method is presented allowing to analyze the signal intensity on printed magnetic resonance images for those cases in which the computer-stored information is lacking.

PATIENTS AND METHODS

A comparative study between magnetic resonance signal and the result of the densitometric analysis was carried out in 29 patients with different haematologic disorders. In order to achieve a suitable standardization, an internal control in both measures was used, i.e., the magnetic resonance signal intensity and the grey intensity of an area of spinal cord, respectively, yielding two ratios: magnetic resonance ratio and grey ratio.

RESULTS

The precision analysis of the densitometric method gave the following results: within-batch coefficient of variation was 1.78%, between-batch coefficient of variation was 1.94% and overall reproducibility 6.4%. The correlation between magnetic resonance ratio and grey ratio was very high, i.e., 0.98 (p < 0.001). Moreover, the regression line displayed on ideal location since it originated in the point 0 and showed a slope of 45 degrees.

CONCLUSION

The densitometric method presented in this paper can be useful for the quantitative analysis of the magnetic resonance signal intensity generated by the haemopoietic bone marrow, for those cases in which the computer-stored information is lacking.

[Vertebral hemangioma and quiescent myeloma: association of therapeutic significance]

Smouldering myeloma is a monoclonal gammopathy in which the M component is higher than 30 g/l and the proportion of plasma cells in the bone marrow is higher than 10% with no anemia, renal failure, hypercalcemia, osteolysis or other features due to the monoclonal gammopathy. The recognition of this clinical variant of myeloma resides in the fact that treatment should be deferred until there are clinical or biologic data indicating evident disease progression. Vertebral hemangioma is a relatively frequent benign tumor in the general population which, although usually asymptomatic, may cause local or radicular bone pain. A patient who fulfilled the criteria of myeloma and who complained of localized bone pain in the spinal column is herein presented. Following a study of the dorsolumbar column by computerized tomography and magnetic resonance, bone lesions with radiologic images characteristic of vertebral hemangioma, clearly different from those observed in myelomatous lesions, were identified. This finding conditioned the treatment, which included radiotherapy for the vertebral hemangioma and no treatment for the smouldering myeloma.

MR in trichloroethane poisoning

We present a case of acute trichloroethane intoxication caused by inhalation of typewriter correction fluid. CT and MR findings revealed lesions in the basal ganglia and cortex similar to those observed in patients with methanol and carbon monoxide poisoning.

Magnetic resonance imaging of paraganglioma of the cauda equina

The authors describe atypical magnetic resonance imaging (MRI) findings for pathologically proven paraganglioma of the filum terminale in a 27-year-old man. MRI showed an intradural tumour, which enhanced after administration of gadolinium and which showed evidence of cystic areas. Hemosiderin rings and vessels were not observed.

An unusual frontal ganglioglioma: CT and MRI

We describe a ganglioglioma with atypical radiological appearances, in an uncommon location. CT showed a nonenhancing low-density lesion without calcification. On MRI the lesion gave nonspecific low signal on T1-weighted images and high signal on T2-weighted images. The tumour was in the right frontal lobe, producing bulging and thinning of the calvarium.

Hepatoblastoma. An attempt to apply histologic classification to aspirates obtained by fine needle aspiration cytology

We applied cytologic and architectural diagnostic criteria to the aspiration smears of six cases of hepatoblastoma (HBL) in order to establish whether it is possible to obtain a reliable cytologic diagnosis of this neoplasm and to subclassify it based on cytologic evidence alone. We describe two groups of HBL, undifferentiated and differentiated. The undifferentiated group comprises anaplastic and embryonal subtypes, and the differentiated group comprises fetal and macrotrabecular subtypes. Our findings suggest that the fetal and macrotrabecular subtypes have a rather characteristic cytologic pattern, permitting us to differentiate between the two and to distinguish them from the other two subtypes. The differential diagnosis between the anaplastic and embryonal subtypes is more complex and can be difficult to carry out using cytologic criteria exclusively. The immunophenotypic pattern reflects the degree of maturity of each subtype and helps with cytologic subclassification. The cytologic differential diagnosis of undifferentiated HBL must include hepatic metastases of small round cell tumors of childhood. The cytologic differential diagnosis between differentiated HBL and hepatocellular carcinoma may be very difficult. We suggest that the cytologic subclassification of HBL is possible with the reservation that the predominant pattern may mask other, associated patterns.

Correlation of MRI hippocampal volume analysis, video/EEG monitoring and inter- and postictal single photon emission tomography in refractory focal epilepsy

The effectiveness of surgery in patients with refractory complex partial seizures depends on accurate localisation of the epileptogenic zone. To assess the correlation between magnetic resonance imaging (MRI) hippocampal volume measurements. Tc 99m-hexamethyl-propyleneamineoxime inter- and postictal single photon emission computed tomography (SPECT) and clinico-electrophysiological (video/EEG) localisation of the epileptogenic zone we prospectively studied 16 consecutive patients with refractory complex partial seizures and no significant abnormality on standard MRI. Each test was interpreted blindly by independent observers. Eight patients (50%) had asymmetrical hippocampal volumes indicative of unilateral atrophy; correlation with the video/EEG and postical SPECT changes was very high (100% with definitive video/EEG localisation, 75% with interictal EEG and 83% with postictal SPECT). Moreover, the left/right hippocampal ratio was able to differentiate temporal from extratemporal video/EEG localisations. Postictal SPECT showed regional lateralised changes in 9 (64%) of 14 technically satisfactory studies. Disagreement between the video/EEG and postictal SPECT was seen with two extratemporal and one bitemporal foci.

[Surgical treatment combined with radiotherapy and chemotherapy in an unselected population of patients with malignant glioma]

BACKGROUND

Malignant gliomas are tumors of bad prognosis with a mean survival of 12 months. In the present report 74 patients diagnosed of malignant glioma were studied with the following aims: 1) evaluate how many could receive combined radiotherapy (RT) and chemotherapy (BCNU) treatment following surgery and 2) analyze whether the patients treated presented a survival similar to that described in the literature.

METHODS

The records of 74 patients operated on for malignant glioma between 1987-1990 and consecutively included in a protocol of treatment with RT and BCNU were reviewed.

RESULTS

Out of the total of 74 patients, 29 (39%) were considered evaluable. The medians of progression free interval and survival were of 10 and 16 months, respectively in these patients. Forty-five (61%) patients could not fulfill the protocol mainly because of tumoral progression prior to completion of RT and severe post surgical complications. The evaluable patients were significantly younger (p = 0.004) and tumoral exeresis wider (p = 0.0003) than in those who were not evaluable.

CONCLUSIONS

Most of the patients operated on for malignant glioma may not receive treatment considered as standard, principally due to tumor progression in the first weeks following surgery and the presence of severe post surgical complications.

Hyperintense globus pallidus on T1-weighted MRI in cirrhotic patients is associated with severity of liver failure

Hyperintense globus pallidus on T1-weighted MRI is present in most patients with advanced liver disease. We evaluated the relationship between the signal intensity of the globus pallidus and clinical or laboratory data of 77 patients eligible for liver transplantation. There was a significant correlation between the intensity of the signal and the Child-Pugh score (as indication of severity of liver disease), presence of postural tremor, previous episodes of variceal bleeding or hepatic encephalopathy, prothrombin activity, serum aspartate and alanine aminotransferase, bilirubin, and the indocyanine green (ICG) hepatic clearance, a very sensitive marker of liver function. The multivariate analysis disclosed that the ICG hepatic clearance and previous episodes of variceal bleeding were independently associated with the signal intensity in the globus pallidus. MRI repeated in 21 patients 10 to 20 months after transplant showed a disappearance of the lesion in all cases. We conclude that the hyperintense globus pallidus is secondary to the severity of the liver disease, and is reversible when liver function returns to normal.

[Primary cerebral lymphoma in 10 patients with AIDS. Comparative clinico-radiologic study with cerebral toxoplasmosis, cerebral tuberculoma and primary cerebral lymphoma in non-immunodepressed patients]

BACKGROUND

Primary central nervous system lymphoma (PCNSL) is the second cause of cerebral masses in patients with the acquired immunodeficiency syndrome (AIDS). The present study evaluated the possible presence of clinical or radiologic signs permitting differentiation of AIDS patients and PCNSL from those with cerebral masses of other etiologies.

METHODS

Clinical history and cranial computerized tomography (CT) of patients with PCNSL and AIDS from the Hospital Clinic i Provincial in Barcelona were reviewed. Results were compared with those of patients with PCNSL without evidence of immunosuppression and with those with AIDS and cerebral toxoplasmosis or tuberculoma diagnosed during the same period.

RESULTS

Of 685 patients with AIDS, 10 were identified with PCNSL. The clinical picture was not different to that observed in patients with AIDS and cerebral toxoplasmosis or tuberculomas. In contrast to PCNSL in non immunodepressed patients, the cerebral CT in patients with PCNSL and AIDS demonstrated hyperdense lesions in only 44% and contrast enhancement was not homogeneous in any case. These characteristics were similar to those observed in the CT of patients with cerebral toxoplasmosis or tuberculoma with the exception that only 8% of the lesions by toxoplasmosis were spontaneously hyperdense.

CONCLUSIONS

The clinical-radiological data of primary central nervous system lymphoma in patients with the acquired immunodeficiency syndrome are similar to those observed in other etiologies. However, the presence of a sole spontaneously hyperdense region in cranial computerized tomography is more suggestive of primary central nervous system lymphoma than cerebral toxoplasmosis.

[Postherpetic vasculopathy. A study of 3 cases in immunosuppressed patients]

We report three cases of postherpetic vasculopathy in immunologically compromised patients. Two had ophthalmic herpes zoster, contralateral to the physical signs, and the third case developed after disseminated herpes zoster. The initial CT images consisted of small ischemic infarcts in capsular regions and basal ganglia. The arteriography showed images consistent with vasculitis or thrombosis of great vessels of the Willis' polygon, which were ipsilateral to the herpetic lesion in two cases. In one patient the neurological defect remained stable, while the other two developed new ischemic episodes, all in the same cerebral hemisphere. It can be assumed from the delayed development of neurologic disease after cutaneous lesions that some cases go unnoticed if the zoster infection is not specifically looked for in retrospect.

[Encephalic toxoplasmosis in patients with the acquired immunodeficiency syndrome. A clinico-radiological study and the therapeutic results in 78 cases]

During a 40-month period 78 episodes of encephalic toxoplasmosis (ET) were diagnosed in 57 patients among 394 with acquired immunodeficiency syndrome (AIDS) (based on CDC criteria) in the Hospital Clinic from Barcelona. 38 patients were parenteral drug abusers (66.7%), 17 were homosexual males (29.8%) and 2 were heterosexual females (3.5%). ET was the first opportunistic infection in 28 patients (49.1%). The most common symptoms at the time of diagnosis were focal neurological signs (62.8%) and fever (52.6%). Usually, computed tomography showed single or multiple hypodense lesions (70.3%) with ring-like (46.1%) or nodular (28.3%) uptake. Serology (indirect immunofluorescence) was diagnostic in only 24 cases (42.1%). The acute episodes were treated with the combination pyrimethamine/sulfadiazine (P/S) during 3-6 weeks, and folinic acid was associated. If the patient had previous allergy to sulfonamides or allergy developed during the acute phase, clindamycin (C) was given instead of S. The patients surviving the acute episode (49, 86, 0%) underwent, if they consented, maintenance therapy with P/S two days per week (15 patients) or with C if sulfonamide allergy was present (10 patients). No relapse was observed in those receiving P/S, but 40% of those treated with P/C relapsed. It was concluded that ET is a common opportunistic infection in the AIDS patients, that the treatment of the acute phase with P/S or with P/C is satisfactory, and that maintenance therapy with P/S two days per week may be effective to prevent relapses.

Central nervous system toxoplasmosis in AIDS patients: efficacy of an intermittent maintenance therapy

Fifty-five episodes of central nervous system (CNS) toxoplasmosis developing in 43 of the 329 AIDS cases seen at our institution were diagnosed during a 34-month period and were prospectively studied. Acute episodes were treated with a pyrimethamine/sulfadiazine (P/S) combination for a mean of 21 days. Because of a previously known major allergy to sulfonamides, three episodes were treated with clindamycin instead of sulphadiazine. In those patients who accepted maintenance therapy, a combination of P/S or pyrimethamine and clindamycin (P/C) was administered 2 days per week. Thirty-six patients (83.7%) survived the first episode. Four of these 36 were lost to further study. Six of the 12 (50%) who decided not to undergo maintenance therapy relapsed (mean follow-up: 12 months). Fourteen patients were given P/S and none relapsed while they were on maintenance therapy (mean follow-up: 10.3 months). Six patients received an intermittent maintenance treatment with P/C and one relapsed 2 months after starting the maintenance therapy (mean follow-up: 13.7 months). We conclude that an intermittent (2 days per week) maintenance treatment for CNS toxoplasmosis with P/S was effective in preventing relapses, although prospective randomized studies remain to be done.

[Spinal cord metastasis of carcinoma of the lung: evaluation of magnetic resonance and computed tomography in its diagnosis]

A patient with lung adenocarcinoma had progressive myelopathy. Computed tomography of spinal cord with intravenous contrast and magnetic resonance scan were negative. At autopsy, a spinal cord metastasis was found. In patients with cancer and clinical suspicion of spinal cord metastasis, palliative treatment with radiotherapy is indicated in spite of negative radiological investigations, so as to prevent the progression of myelopathy.

[Hemangioma of the vertebrae: contribution of magnetic resonance to its study]

Vertebral hemangioma is a benign vascular tumor predominantly involving the dorsolumbar spine. Although most of these tumors are asymptomatic, they may result in radiculopathy and/or compressive myelopathy. Plain X-ray films and computed tomography (CT) generally permit the diagnosis by showing characteristic images with hypertrophic bone trabeculation in the vertebral body. We report three patients with vertebral hemangioma in which CT was diagnostic. Magnetic resonance (MR) with low intensity field was inferior to CT for the suggestion of the diagnosis of hemangioma, but had a better definition for subarachnoid space obliteration and spinal cord compression.

Angiographic diagnosis of cerebral oedema

Cerebral oedema is usually associated with brain vascular lesions, such as infarction, neoplasms, angiitis, thrombophlebitis, etc. and we consider that angiographic examination is essential for the diagnosis. In this paper we analyse the angiographic signs of cerebral oedema and the differential diagnosis between oedema and any associated lesions. We also consider that it is very important to establish a diagnosis between primary oedema and hydrocephalus with a view to establishing the correct treatment in each case.

Morphological aspects of the vessels of brain tumours

The vascular changes associated with cerebral tumours are demonstrated angiographically and histologically.

The tolosa-hunt syndrome: report of two cases

The Tolosa-Hunt Syndrome consists of intermittent painful ophthalmoplegia resulting from a non-specific inflammatory process in the cavernous sinus and superior orbital fissure, which responds to steroid therapy. We report two additional cases to the literature of the Tolosa-Hunt Syndrome and we are interested in pointing out the importance of orbital venography in the diagnosis of this syndrome. Orbital venography demonstrates the partial occupation of the cavernous sinus and the lack of visualization of the 3rd segment of the superior ophthalmic vein.