Evaluation of the INTERPRET decision-support system: can it improve the diagnostic value of magnetic resonance spectroscopy of the brain?

PURPOSE: We evaluated in a clinical setting the INTERPRET decision-support system (DSS), a software generated to aid in MRS analysis to achieve a specific diagnosis for brain lesions. METHODS: The material consisted of 100 examinations of focal intracranial lesions with confirmed diagnoses. MRS was obtained at 1.5 T using TE 20-30 ms. Data were processed with the LCModel for conventional analysis. The INTERPRET DSS 3.1. was used to obtain specific diagnoses. MRI and MRS were reviewed by one interpreter. DSS analysis was made by another interpreter, in 80 cases by two interpreters. The diagnoses were compared with the definitive diagnoses. For comparisons between DSS, conventional MRS analysis, and MRI, the diagnoses were categorised: high-grade tumour, low-grade tumour, non-neoplastic lesion. RESULTS: Interobserver agreement in choosing the diagnosis from the INTERPRET database was 75%. The diagnosis was correct in 38/100 cases, incorrect in 57 cases. No good match was found in 5/100 cases. The diagnostic category was correct with DSS/conventional MRS/MRI in 67/58/52 cases, indeterminate in 5/8/20 cases, incorrect in 28/34/28 cases. Results with DSS were not significantly better than with conventional MRS analysis. All definitive diagnoses did not exist in the INTERPRET database. In the 61 adult patients with the diagnosis included in the database, DSS/conventional MRS/MRI yielded a correct diagnosis category in 48/32/29 cases (DSS vs conventional MRS: p = 0.002, DSS vs MRI: p = 0.0004). CONCLUSION: Use of the INTERPRET DSS did not improve MRS categorisation of the lesions in the unselected clinical cases. In adult patients with lesions existing in the INTERPRET database, DSS improved the results, which indicates the potential of this software with an extended database.

Cognitive function in very old men does not correlate to biomarkers of Alzheimer's disease.

BACKGROUND: The Alzheimer's disease (AD) brain displays atrophy with amyloid-ß (Aß) and tau deposition, whereas decreased Aß42 and increased tau are measured in cerebrospinal fluid (CSF). The aim of this study was to relate cognitive performance to the degree of brain atrophy, CSF biomarker levels and neuropathology in a cohort of aged men. METHODS: Fifty-eight 86-92-year-old men from the Uppsala Longitudinal Study of Adult Men (ULSAM) cohort underwent cognitive testing, brain computed tomography and lumbar puncture. Atrophy was graded with established scales. Concentrations of CSF Aß42, t-tau and p-tau were measured by ELISA. Thirteen brains were examined post mortem. RESULTS: Forty-six of the individuals were considered non-demented, whereas twelve were diagnosed with dementia, either at baseline (n = 4) or during follow-up (n = 8). When comparing subjects with and without dementia, there were no differences in the degree of atrophy, although the mini mental state examination (MMSE) scoring correlated weakly with the degree of medial temporal atrophy (MTA) (p = 0.04). Moreover, the CSF biomarker levels did not differ significantly between healthy (n = 27) and demented (n = 8) subjects (median values 715 vs 472 pg/ml for Aß42, 414 vs 427 pg/ml for t-tau and 63 vs 60 pg/ml for p-tau). Similarly, there were no differences in the biomarker levels between individuals with mild (n = 24) and severe (n = 11) MTA (median values 643 vs 715 pg/ml for Aß42, 441 vs 401 pg/ml for t-tau and 64 vs 53 pg/ml for p-tau). Finally, the neuropathological changes did not correlate with any of the other measures. CONCLUSION: In this cohort of aged men only a weak correlation could be seen between cognitive performance and MTA, whereas the various neuroradiological, biochemical and neuropathological measures did not correlate with each other. Thus, AD biomarkers seem to be less informative in subjects of an advanced age.

Neuropathology of the hippocampus in FTLD-Tau with Pick bodies: a study of the BrainNet Europe Consortium.

AIMS: Frontotemporal lobar degeneration with Pick bodies (Pick's disease) is characterized by the presence of tau immunoreactive spherical structures in the cytoplasm of neurones. In view of confusion about the molecular pathology of Pick's disease, we aimed to evaluate the spectrum of tau pathology and concomitant neurodegeneration-associated protein depositions in the characteristically affected hippocampus. METHODS: We evaluated immunoreactivity (IR) for tau (AT8, 3R, 4R), α-synuclein, TDP43, p62, and ubiquitin in the hippocampus, entorhinal and temporal cortex in 66 archival cases diagnosed neuropathologically as Pick's disease. RESULTS: Mean age at death was 68.2 years (range 49-96). Fifty-two (79%) brains showed 3R immunoreactive spherical inclusions in the granule cells of the dentate gyrus. These typical cases presented mainly with the behavioural variant of frontotemporal dementia, followed by progressive aphasia, mixed syndromes or early memory disturbance. α-Synuclein IR was seen only in occasional spherical tau-positive inclusions, TDP-43 IR was absent, and 4R IR was present only as neurofibrillary tangles in pyramidal neurones. Aß IR was observed in 16 cases; however, the overall level of Alzheimer's disease-related alterations was mainly low or intermediate (n = 3). Furthermore, we identified six cases with unclassifiable tauopathy. CONCLUSIONS: (i) Pick's disease may occur also in elderly patients and is characterized by a relatively uniform pathology with 3R tau inclusions particularly in the granule cells of dentate gyrus; (ii) even minor deviation from these morphological criteria suggests a different disorder; and (iii) immunohistological revision of archival cases expands the spectrum of tauopathies that require further classification.

CSF biomarkers for Alzheimer disease correlate with cortical brain biopsy findings.

OBJECTIVE: To assess the relationship between Alzheimer disease (AD)-related pathologic changes in frontal cortical brain biopsy and AD biomarkers in ventricular vs lumbar CSF, and to evaluate the relationships of AD biomarkers in CSF and cortical biopsy with the final clinical diagnosis of AD. METHODS: In 182 patients with presumed normal pressure hydrocephalus (152 with known APOE carrier status), Aß plaques and tau in the cortical brain biopsies were correlated with the ventricular and lumbar CSF Aß42, total tau, and p-tau levels measured by ELISA. In a median follow-up of 2.0 years, 51 patients developed AD dementia. RESULTS: The patients with Aß plaques in the cortical biopsy had lower (p = 0.009) CSF Aß42 levels than those with no Aß plaques. The patients with tau in the cortical biopsy had lower (p = 0.014) Aß42 but higher (p = 0.015) p-tau 181 in CSF as compared to those with no tau in the cortical biopsy. The patients with amyloid + tau + biopsies had the lowest Aß42 and highest tau and p-tau 181 levels in CSF. The Aß42 levels were lower and the tau and p-tau 181 higher in the ventricular vs corresponding lumbar CSF samples. In multivariate analysis, the presence of cortical Aß was independently predicted by the APOE ε4 carrier status and age but not by CSF Aß42 or tau levels. CONCLUSIONS: Amyloid plaques and hyperphosphorylated tau in cortical brain biopsies are reflected by low CSF Aß42 and high CSF tau and p-tau levels, respectively.

Divergent clinical and neuropathological phenotype in a Gerstmann-Sträussler-Scheinker P102L family.

OBJECTIVES: Gerstmann-Sträussler-Scheinker syndrome belongs to the genetic prion diseases being associated with mutations in the prion protein gene (PRNP). The most common is the point mutation at codon 102, leading to the substitution of proline to leucine (P102L). Previous reports have indicated a phenotypic heterogeneity among individuals with this mutation. Here, we describe the clinical and pathological phenotype in members of the first Finnish kindred with the P102L mutation in the PNRP gene. MATERIALS AND METHODS: Genetic and clinical information was available in five members of a family, while a systematic histologic and immunohistochemical assessment of the post-mortem brain was carried out in three. RESULTS: Clinical presentation, disease duration and the clinical phenotype (ataxia vs dementia) varied between patients. There was a significant correlation between clinical symptoms and the neuroanatomical distribution of prion protein-immunoreactive aggregates, i.e. subtentorial predominance in ataxia vs cortical predominance in dementia. A significant concomitant Alzheimer is disease-related pathology was observed in the brain of one patient with dementia as onset symptom. CONCLUSIONS: This is the first Scandinavian family carrying the P102L mutation in the PRNP gene. Gerstmann-Sträussler-Scheinker syndrome should be considered in the differential diagnosis when handling with patients with ataxia and/or dementia of unclear aetiology.

Post-mortem findings in 10 patients with presumed normal-pressure hydrocephalus and review of the literature.

AIMS: Neuropathological features of idiopathic normal-pressure hydrocephalus (iNPH) are poorly characterized. Brain biopsy during life may help in the differential diagnosis of dementia, but post-mortem validation of biopsy findings is scarce. Here we review and report brain biopsy and post-mortem neuropathological findings in patients with presumed NPH. METHODS: We evaluated 10 patients initially investigated by intraventricular pressure monitoring and a frontal cortical biopsy for histological and immunohistochemical assessment as a diagnostic procedure for presumed NPH. RESULTS: Out of the 10 patients, eight were shunted and seven benefited. Until death, six had developed severe and two mild cognitive impairment. One was cognitively unimpaired, and one was mentally retarded. Three subjects displayed amyloid-ß (Aß) aggregates in their frontal cortical biopsy obtained at the initial procedure. One of these patients developed Alzheimer's disease during a follow-up time of nearly 10 years. One patient with cognitive impairment and NPH suffered from corticobasal degeneration. In six patients various vascular lesions were seen at the final neuropathological investigation. Five of them were cognitively impaired, and in four vascular lesions were seen sufficient in extent to be considered as causative regarding their symptoms. CONCLUSIONS: The frequent finding of vascular pathology in NPH is intriguing, suggesting that vascular alterations might be causative of cognitive impairment in a notable number of patients with NPH and dementia. Brain biopsy can be used to detect Aß aggregates, but neuropathological characteristics of iNPH as a distinct disease still need to be discovered.

Brain pathology in three subjects from the same pedigree with presenilin-1 (PSEN1) P264L mutation.

AIMS: Our goal was to assess pathological lesions with respect to type and distribution and to compare these results with the clinical presentation including symptoms and mode of progression in three members of the same pedigree with a P264L presenilin-1 gene mutation. METHODS: We used immunohistochemistry and a tissue microarray technique applied to post mortem brain tissue samples. RESULTS: All three subjects were demented, one subject displayed spastic paraparesis and two had Parkinsonism. All three cases displayed abundant cotton wool plaques composed of amyloid-beta42 but also containing other proteins, for example, hyperphosphorylated tau and in one case TAR DNA binding protein 43. The distribution of the pathology varied and seemed to some extent to be related to the clinical phenotype. An association was detected between neocortical/thalamic involvement and psychiatric symptoms, between striatal/amygdaloid involvement and Parkinsonism, and between brainstem involvement and spastic paraparesis. CONCLUSIONS: Subjects from the same pedigree carrying the same mutation display a clear variability in the type and distribution of pathology as well as in their clinical symptoms. These results emphasize that still unknown factors significantly alter the pathological and clinical phenotypes in genetically predetermined disease.

pH measurement as quality control on human post mortem brain tissue: a study of the BrainNet Europe consortium.

AIMS: Most brain diseases are complex entities. Although animal models or cell culture experiments mimic some disease aspects, human post mortem brain tissue remains essential to advance our understanding of brain diseases using biochemical and molecular techniques. Post mortem artefacts must be properly understood, standardized, and either eliminated or factored into such experiments. Here we examine the influence of several premortem and post mortem factors on pH, and discuss the role of pH as a biochemical marker for brain tissue quality. METHODS: We assessed brain tissue pH in 339 samples from 116 brains provided by 8 different European and 2 Australian brain bank centres. We correlated brain pH with tissue source, post mortem delay, age, gender, freezing method, storage duration, agonal state and brain ischaemia. RESULTS: Our results revealed that only prolonged agonal state and ischaemic brain damage influenced brain tissue pH next to repeated freeze/thaw cycles. CONCLUSIONS: pH measurement in brain tissue is a good indicator of premortem events in brain tissue and it signals limitations for post mortem investigations.

Beta-amyloid deposition in brains of subjects with diabetes.

AIM: A causative association between diabetes mellitus (DM) and Alzheimer's disease (AD) has been suggested based on clinical and epidemiological studies. One hypothesis is that the link between DM and AD is related to the function of insulin-degrading enzyme (IDE), an enzyme that degrades not only insulin and pancreatic amylin but also beta-amyloid (Abeta). Thus, in diabetics, insulin and Abeta might compete for IDE and this might lead to an increase in Abeta. The objective of this study was to test the hypothesis that hyperinsulinaemia can elevate Abeta levels and thus contribute to AD pathology in humans. METHODS: Neuropathological examination was carried out employing conventional and immunohistochemical (IHC) methods of the brains obtained post mortem from 701 aged subjects. RESULTS: The loads of IHC/Abeta, silver stained neuritic plaques (NP) and neurofibrillary tangles (NFT) were significantly higher in subjects carrying the Apolipoprotein E e4 allele. In contrast, the loads of Abeta, NPs and NFT in the brains were not influenced by hyperglycaemia when comparing 134 diabetic with 567 non-diabetic subjects. CONCLUSIONS: We conclude that the hypothesis that hyperinsulinaemia would significantly elevate the Abeta load and thus increase the extent of AD pathology cannot be supported. Our result challenges the claim that DM is a direct risk factor of developing AD. Thus further studies on pathological lesions in demented diabetics should be conducted.

Use of p62/SQSTM1 antibodies for neuropathological diagnosis.

The demonstration of proteinaceous inclusions in the brain is the key step in the pathological diagnosis of degenerative dementias. The diversity of these diseases has necessitated the use of a panel of (immuno)stains to visualize all suspect pathologies, elevating diagnostic costs. Immunodetection of p62 (sequestosome 1), an abundant constituent in diverse pathological inclusions, holds the potential for a broad-specificity, high-contrast inclusion label. In the brain, pathological p62-positive aggregates comprise both cytoplasmic and nuclear types in neurones and glia, with abnormal tau, alpha-synuclein, TAR DNA-binding protein 43 or polyglutamine proteins as primary components. We therefore set out to evaluate the performance of p62 antibodies for diagnostic immunohistochemistry. We optimized the application conditions and compared the staining profiles of eight commercial p62 antibodies with each other and with reference immunostains, using 2-mm tissue multiarrays representing the major tauo- and synucleinopathies and frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U). The lesions were best visualized using monoclonal antibodies, displaying most types of hallmark inclusions with excellent contrast. Expanding the list of p62-containing aggregates, we demonstrated p62 in tufted astrocytes, coiled bodies, astrocytic plaques, and variform neocortical inclusions and pathological processes in FTLD-U. Polyclonal antibodies exhibited lower sensitivities with variable background levels. We also noted more subtle p62-immunoreactive features lacking overt disease associations. Emphasizing the importance of proper antibody and epitope unmasking methods for maximum sensitivity, we recommend p62 immunodetection as a screening stain for diagnostic practice.

Abundant glial alpha-synuclein pathology in a case without overt clinical symptoms.

Screening of 1,800 brains with alpha-synuclein (alphaS) immunohistochemistry revealed five cases with abundant glial cytoplasmic inclusions (GCIs) within the white matter of the brainstem. Surprisingly, retrospective clinical assessment showed that one of these subjects did not fulfil the currently recommended clinical consensus criteria for the multiple system atrophy (MSA). One of the hallmark lesions of MSA, alphaS-positive GCIs, were widespread and abundant in this atypical case that nonetheless lacked any significant neuronal loss. If the patient had met the clinical criteria for MSA, the neuropathological phenotype would have undeniably confirmed the clinically suggested diagnosis. However, lacking overt clinical signs of MSA, the neuropathological phenotype in this subject is prone to be variably denoted or overlooked. We would therefore like to advise neuropathologists to acknowledge these cases with "occult" alpha-synucleinopathy and to inform the clinicians of such a finding. Whether these cases represent a preclinical stage of MSA or simply a biological coincidence, is yet unknown. The observation of abundant GCIs in an asymptomatic subject is, however, important, because even if these cases are rare in number, their occurrence challenge the current presumption, whereby simply the number of alphaS-positive GCIs mediates the neuronal dysfunction responsible for the clinical symptoms of MSA.

How a neuropsychiatric brain bank should be run: a consensus paper of Brainnet Europe II.

The development of new molecular and neurobiological methods, computer-assisted quantification techniques and neurobiological investigation methods which can be applied to the human brain, all have evoked an increased demand for post-mortem tissue in research. Psychiatric disorders are considered to be of neurobiological origin. Thus far, however, the etiology and pathophysiology of schizophrenia, depression and dementias are not well understood at the cellular and molecular level. The following will outline the consensus of the working group for neuropsychiatric brain banking organized in the Brainnet Europe II, on ethical guidelines for brain banking, clinical diagnostic criteria, the minimal clinical data set of retrospectively analyzed cases as well as neuropathological standard investigations to perform stageing for neurodegenerative disorders in brain tissue. We will list regions of interest for assessments in psychiatric disorder, propose a dissection scheme and describe preservation and storage conditions of tissue. These guidelines may be of value for future implementations of additional neuropsychiatric brain banks world-wide.

Cerebroretinal microangiopathy with calcifications and cysts.

BACKGROUND: Extensive cerebral calcifications and leukoencephalopathy have been reported in two rare disorders Coats plus and leukoencephalopathy with calcifications and cysts. In the latter, a progressive formation of parenchymal brain cysts is a special feature, whereas Coats plus is characterized by intrauterine growth retardation, bilateral retinal telangiectasias and exudations (Coats disease), sparse hair, and dysplastic nails without cyst formation. METHODS: We identified 13 patients, including two pairs of siblings, with extensive cerebral calcifications and leukoencephalopathy. We reviewed clinical, ophthalmologic, radiologic and neuropathologic data of seven deceased patients and studied five patients prospectively. RESULTS: Eleven patients were small for gestational age; the other symptoms emerged from infancy to adolescence. All patients had neurologic symptoms including seizures, spasticity, dystonia, ataxia, and cognitive decline. Progressive intracerebral calcifications involved deep gray nuclei, brainstem, cerebral and cerebellar white matter, and dentate nuclei and were accompanied by diffuse white matter signal changes and, in five patients, cerebral cysts. Eleven patients had retinal telangiectasias or angiomas. Additional features were skeletal and hematologic abnormalities, intestinal bleeding, and poor growth. Neuropathologic examination showed extensive calcinosis and abnormal small vessels with thickened, hyalinized wall and reduced lumen. CONCLUSIONS: Our data suggest that Coats plus syndrome and leukoencephalopathy with calcifications and cysts belong to the same spectrum. The primary abnormality seems to be an obliterative cerebral angiopathy involving small vessels, leading to dystrophic calcifications via slow necrosis and finally to formation of cysts and secondary white matter abnormalities.

Protein p62 common in invaginations in benign meningiomas--a possible predictor of malignancy.

OBJECTIVE: It is known that p62 is a cytosolic conserved protein that binds non-covalently to ubiquitin. Expression of p62 has been seen in inclusions in neoplasias like hepatocellular and breast carcinomas but also in neuronal inclusions of degenerative brain disorders. Dysfunction of ubiquitin system leads to presence of p53 in cells suggested to be a predictor of future recurrence of meningioma. MATERIAL: The study material included 45 benign meningiomas of postmenopausal women operated in Kuopio University Hospital between 1994 and 2002. METHODS: Patterns of p62 immunopositivity in meningiomas was evaluated and the results were correlated to clinical and histological parameters. RESULTS: Constant p62 labeling in at least each field measuring 1 mm in diameter was detected consisting of 5 different patterns. The most common labeling was seen in nuclear invaginations either as grains or homogenous labeling, followed by Marinesco like nuclear inclusions or rode like inclusions outside the invagination. In some cases cytoplasmic granular staining was seen. No correlation between different p62 patterns or extent of p62 expression, histological subtypes or proliferation marker Ki-67 was noted. CONCLUSION: Our results indicate that in the benign not recurrent meningiomas, signs of functioning proteosomal system, can be detected using the p62 labeling. The function of proteosomal system in malignant and specifically invasive meningiomas needs to be further elucidated.

Polymorphisms in neprilysin gene affect the risk of Alzheimer's disease in Finnish patients.

OBJECTIVES: Neprilysin (NEP) is an amyloid beta-peptide (Abeta) degrading enzyme expressed in the brain, and accumulation of Abeta is the neuropathological hallmark in Alzheimer's disease (AD). In this study we investigated whether polymorphisms in the NEP gene have an effect on the risk for AD. METHODS: The frequencies of seven single nucleotide polymorphisms (SNPs) and apolipoprotein E (APOE) were assessed in 390 AD patients and 468 cognitively healthy controls. Genotypes of the study groups were compared using binary logistic regression analysis. Haplotype frequencies of the SNPs were estimated from genotype data. RESULTS: Two SNPs, rs989692 and rs3736187, had significantly different allelic and genotypic frequencies (uncorrected p = 0.01) between the AD and the control subjects and haplotype analysis showed significant association between AD and NEP polymorphisms. CONCLUSION: Taken together, these findings suggest that polymorphisms in the NEP gene increase risk for AD and support a potential role for NEP in AD.

Preoperative clinical evaluation, outline of surgical technique and outcome in temporal lobe epilepsy.

Temporal lobe epilepsy (TLE) is the most common type of refractory epilepsy. The mechanisms of epileptogenesis and seizure semiology of the mesial and neocortical temporal lobe epilepsy are discussed. The evaluation and selection of patients for TLE surgery requires team work: the different clinical aspects of neuropsychological evaluation, magnetic resonance and functional imaging (positron emission tomography, single photon emission computed tomography and magnetoenephalography) are reviewed. In our programme of epilepsy surgery at Kuopio University Hospital, Finland, we have performed 230 temporal resections from 1988 until 2002. Preoperative diagnostic EEG-videotelemetry often required intracranial monitoring and it has proved to be safe and efficient. The indications and technique for tailored temporal lobe resection with amygdalohippocampectomy used in our institution, as well as the complications, are described. Our analysis of outcome after temporal lobe surgery included 140 consecutive adult patients between 1988 and 1999; one year after the operation in unilateral TLE the Engel I-II outcome was observed in 68% of the patients. Outcome of surgery improved significantly after introduction of the standardised MR imaging protocol from 1993; 74% of patients with unilateral TLE achieved Engel I-II outcome.

Brain biopsy prior to treatment of Alzheimer's disease.

A cortical biopsy was analyzed using immunohistochemical methodology in a total of 213 patients with suspected normal pressure hydrocephalus (NPH). Normal intracranial pressure (ICP) was registered in 121 (43 %) of patients with suspected NPH. The incidence of Alzheimer's disease (AD) related lesions was quite high, since 38 % of all subjects displayed beta-amyloid (betaA4) aggregates and in 8 % of subjects paired helical filament-tau (PHF-tau) pathology was noted. The AD associated pathologies were more common in subjects with normal than elevated ICP. Of the 121 subjects with NPH, 16 (13 %) had subclinical, histopathologically verified AD and a further 40 subjects (33 %) could be considered to be at high risk to develop AD. Pharmacological treatment trials of AD should be carried out on subjects with evident brain pathology (betaA4 aggregates or PHF-tau pathology) especially during the early stage of the disease, i.e., the subclinical stage. For this purpose a simple cortical biopsy with a low risk of complication would represent a diagnostic "method" of choice.

Castleman's disease of the leptomeninges--immunohistochemical findings in 2 cases.

OBJECTIVE: Castleman's disease is an uncommon benign lymphoproliferative disorder that arises in lymph nodes. Few cases of Castleman's disease affecting the central nervous system have been described. CASE HISTORY: We report 2 new cases of Castleman's disease confined solely to the leptomeninges. The patients were referred to neurosurgery with presumptive clinical diagnosis of meningiomas. Histological investigation of the operative specimens taken from the abnormal leptomeninges revealed nodular lymphoid areas with multiple germinal centers surrounded by concentrically layered proliferations of small lymphocytes. Histologically, these 2 cases fulfilled the classification criteria for the mixed and for the hyaline-vascular type of Castleman's disease. The immunohistochemical analysis revealed a polyclonal B cell proliferation in the lesions with perifollicular T cell proliferation with the T helper cell predominance. CONCLUSIONS: The authors conclude that Castleman's disease involving the leptomeninges have a similar immunological pattern reported for the disease in extracranial locations and that, though being rare, Castleman's disease should be considered as a differential diagnosis when dealing with mass lesions of leptomeninges.

Long term outcome of temporal lobe epilepsy surgery: analyses of 140 consecutive patients.

OBJECTIVE: To analyse the long term results of temporal lobe epilepsy surgery in a national epilepsy surgery centre for adults, and to evaluate preoperative factors predicting a good postoperative outcome on long term follow up. METHODS: Longitudinal follow up of 140 consecutive adult patients operated on for drug resistant temporal lobe epilepsy. RESULTS: 46% of patients with unilateral temporal lobe epilepsy became seizure-free, 10% had only postoperative auras, and 15% had rare seizures on follow up for (mean (SD)) 5.4 (2.6) years, range 0.25 to 10.5 years. The best outcome was after introduction of a standardised magnetic resonance (MR) imaging protocol (1993-99): in unilateral temporal lobe epilepsy, 52% of patients became seizure-free, 7% had only postoperative auras, and 17% had rare seizures (median follow up 3.8 years, range 0.25 to 6.5 years); in palliative cases (incomplete removal of focus), a reduction in seizures of at least 80% was achieved in 71% of cases (median follow up 3.1 years, range 1.1 to 6.8 years). Most seizure relapses (86%) occurred within one year of the operation, and outcome at one year did not differ from the long term outcome. Unilateral hippocampal atrophy with or without temporal cortical atrophy on qualitative MR imaging (p < 0.001, odds ratio (OR) 5.2, 95% confidence interval (CI) 2.0 to 13.7), other unitemporal structural lesions on qualitative MR imaging (p < or = 0.001, OR 6.9, 95% CI 2.2 to 21.5), onset of epilepsy before the age of five years (p < 0.05, OR 2.9, 95% CI 1.2 to 7.2), and focal seizures with ictal impairment of consciousness and focal ictal EEG as a predominant seizure type (p < 0.05, OR 3.4, 95% CI 1.2 to 9.1) predicted Engel I-II outcome. Hippocampal volume reduction of at least 1 SD from the mean of controls on the side of the seizure onset (p < 0.05, OR 3.1, 95% CI 1.1 to 9.2) also predicted Engel I-II outcome. CONCLUSIONS: Outcome at one year postoperatively is highly predictive of long term outcome after temporal lobe epilepsy surgery. Unitemporal MR imaging abnormalities, early onset of epilepsy, and seizure type predominance are factors associated with good postoperative outcome.