Salivary gland tissues and derived primary and metastatic neoplasms: unusual pitfalls in the work-up of sellar lesions. A systematic review.

PURPOSE: Salivary gland (SG) tissue and derived neoplasms may occur in the sellar region. As the current literature is mostly limited to case reports, the puzzling case of an inflammatory SG removed by transsphenoidal surgery (TS) and mimicking a prolactinoma prompted us to perform the first systematic review of these unusual conditions. METHODS: A systematic literature search was conducted according to the PRISMA guidelines. Forty-four individual cases-non-neoplastic enlarged salivary glands (NNESG, n = 15), primary benign (n = 7) and malignant (n = 8) ectopic salivary tumours (ST) and sellar metastasis from eutopic primary ST (n = 14)-were suitable for the analysis of clinical, radiological and pathological characteristics. Therapeutic outcome was reviewed as a secondary endpoint. RESULTS: All cases were diagnosed after surgery. NNESG commonly affected young and/or female patients, typically leading to headaches and hyperprolactinemia and originating close to the neurohypophysis. Submucosal SG should be excluded before concluding to an intrasellar NNESG after TS. No gender or age predominance was found for primary ectopic ST, which present as large tumors, with histological phenotypes similar to common ST. Hypopituitarism and diabetes insipidus were more frequent in ST than in NNESG. NNESG and benign ectopic ST rarely recur. Malignant ectopic ST should be distinguished from secondary localizations of eutopic ST reaching the sella by contiguity or metastatic spread; both share a frequent unfavorable outcome. CONCLUSION: Sellar neoplasms derived from SG are rare but misleading conditions and pituitary dysfunction is likely to be more common than currently reported. Appropriate pathological evaluation and multidisciplinary approach are required.

Temporal summation of the nociceptive withdrawal reflex involves deactivation of posterior cingulate cortex.

BACKGROUND: Temporal summation of pain sensation is pivotal both in physiological and pathological nociception. In humans, it develops in parallel with temporal summation of the nociceptive withdrawal reflex (NWR) of the lower limb, an objective representation of the temporal processing of nociceptive signals into the spinal cord. METHODS: To study the contribution of cortical and subcortical structures in temporal summation of pain reflex responses, we compared the fMRI signal changes related to the temporal summation threshold (TST) of the NWR with that related to the single NWR response. We studied 17 healthy subjects using a stimulation paradigm previously determined to evoke both the TST of the NWR (SUMM) and the NWR single response (SING). RESULTS: We found a significant activation in left (contralateral) primary somatosensory cortex (SI), bilateral secondary somatosensory cortex (SII), bilateral insula, anterior cingulate cortex (ACC) and bilateral thalamus during both SUMM and SING conditions. The SUMM versus SING contrast revealed a significant deactivation in the posterior cingulate cortex (PCC) and bilateral middle occipital gyrus in SUMM when compared to SING condition. CONCLUSIONS: Our data support the hypothesis that temporal summation of nociceptive reflex responses is driven through a switch between activation and deactivation of a specific set of brain areas linked to the default mode network. This behaviour could be explained in view of the relevance of the pain processing induced by temporal summation, recognized as a more significant potential damaging condition with respect to a single, isolated, painful stimulation of comparable pain intensity. SIGNIFICANCE: The study demonstrated that TST of the NWR involves a selective deactivation of PCC.

Apparent diffusion coefficient obtained by magnetic resonance imaging as a prognostic marker in glioblastomas: correlation with MGMT promoter methylation status.

OBJECTIVE: To evaluate whether apparent diffusion coefficient (ADC) values can predict the status of MGMT of glioblastoma multiforme (GBM) and correlate with overall survival (OS) and progression-free survival (PFS). METHODS: This retrospective study included 47 patients with pathologically proven glioblastoma. All of them underwent MR DWI study before surgery (mean time 1 week) and the status of methylguanine-DNA-methyltransferase (MGMT) promoter methylation was searched for. Minimum apparent diffusion coefficient (ADC) values were evaluated. OS and PSF parameters were calculated, and Student's t-test, Kaplan-Meier curves, linear and Cox regression were performed. RESULTS: Twenty-five patients showed positive methylation of the MGMT promoter. Patients showing MGMT promoter methylation had higher minimum ADC values, and they survived longer than those without MGMT promoter methylation. The median ADCmin value of 0.80 represents the cutoff value able to distinguish between methylated and un-methylated patients. Patients showing minimum ADC values higher than 0.80 survived longer than patients with minimum ADC values lower than 0.80. A linear correlation between minimum ADC values vs. the OS and PFS was observed. CONCLUSIONS: Minimum ADC values in glioblastoma multiforme could be used as a preoperative parameter to estimate the status of MGMT promoter methylation and the survival of patients.

Subacute combined degeneration without nutritional anemia.

Subacute combined degeneration (SCD) is a rare neurological complication of cobalamin deficiency, characterized by demyelination of the dorsal and lateral spinal cord. The diagnosis and treatment of SCD can be delayed if a patient does not present with clear clinical and laboratory signs of nutritional anemia, which has a marked effect on neurological recovery. We report a 62-year-old man with SCD with a history of gastric cancer and chronic alcoholism who presented with ataxia, gait disturbance, urinary incontinence, and limb weakness, but without other clinical or laboratory signs of cobalamin deficiency. The SCD diagnosis was confirmed by 3-Tesla MRI, which showed intramedullary signal alteration in the posterior columns of the entire spinal cord.

Intraoperative localization of subcortical brain lesions.

BACKGROUND: Some brain tumors may grow immediately beneath the cortical surface without distorting its appearance. Intraoperative image guidance promotes safe resection. We have developed MRI-based corticotopography (MRI-bct), to localize lesions during surgery, using simple, non-dedicated equipment, to match a three-dimensional reconstruction with the corresponding appearance of the brain cortex. METHODS: Forty-six patients underwent resection of subcortical brain lesions, aided by MRI-bct. The lesions had a maximum diameter less than 3 cm, were subcortical but no deeper than the floor of the nearest cerebral sulcus. Each patient had a volumetric MRI scan with and without contrast administration. Data sets were transferred to a laptop personal computer and processed using a rendering software. At operation, the three-dimensional model of the brain, including a surface overlay of the lesion, was matched to the exposed brain surface. After its exact relationship with the overlying sulcal pattern was defined, the lesion was localized and resected. In selected patients, the procedure was coupled with functional brain mapping. RESULTS: Data processing took from 10 to 15 min and could be done whenever convenient before operation. Surface matching between the surgical field and the reformatted MRI always required less than 5 min and was done near the operating table. In all patients, the lesion was identified at the first attempt, through a small corticotomy, regardless of the brain shift after dural opening. CONCLUSIONS: MRI-bct is a practical, time-saving neuronavigational aid ideal for localizing superficial lesions underlying the cerebral cortex because it unmistakably characterizes the adjacent sulcal anatomy.

Intramedullary teratomas: Two case reports and a review of the literature.

OBJECTIVE: Intramedullary teratomas are extremely rare tumours. A review of the literature found only reports of 59 cases, three of which were treated by us. The most common localisation for these tumours is in the medullary conus. According to our experience as well as more recent reports, MRI images allow a preoperative diagnosis to be made. CLINICAL PRESENTATION: We treated two cases of intramedullary teratoma of the conus: that of a 41-year-old woman and that of a 40-year-old man. Both suffered from motor and sensory disorders, and the woman also suffered from urinary disorders. CT and MRI enabled us to diagnose an intramedullary tumour and to suspect a dysembryogenic origin. INTERVENTION: Both patients were treated surgically; the surgical removal of the tumour was extensive but not total because of the tenacious adhesions of the tumour to the adjacent parenchyma. CONCLUSION: Surgery is the therapy of choice in cases of intramedullary teratomas; the removal, though incomplete, leads to a definite improvement of symptoms. In our two cases the follow-up has been 7 years and 6 years, respectively. No tumour regrowth occurred during this period.

Somatomotor functional MRI in a hypertensive arachnoid cyst.

In this article the authors report the study by functional MRI, before and after surgery, of the motor cerebral cortex surrounding a large hypertensive arachnoid cyst. They stress that the functional modifications due to surgery are more relevant than suggested by the simple morphological data.

A rapid and reliable procedure to localize subdural electrodes in presurgical evaluation of patients with drug-resistant focal epilepsy.

OBJECTIVES: To evaluate a novel method for localization of subdural electrodes in presurgical assessment of patients with drug-resistant focal epilepsy. METHODS: We studied eight consecutive patients with posterior epilepsy in whom subdural electrodes were implanted for presurgical evaluation. Electrodes were detected on post-implantation brain CT scans through a semiautomated procedure based on a MATLAB routine. Then, post-implantation CT scans were fused with pre-implantation MRI to localize the electrodes in relation to the underlying cortical structures. The reliability of this procedure was tested by comparing 3D-rendered MR images of the electrodes with electrode position as determined by intraoperative digital photography. RESULTS: In each patient, all electrodes could be correctly localized and visualized in a stereotactic space, thus allowing optimal surgery planning. The agreement between the procedure-generated images and the digital photographs was good according to two independent raters. The mean mismatch between the 3D images and the photographs was 2 mm. CONCLUSIONS: While our findings need confirmation on larger samples including patients with anterior epilepsy, this procedure allowed to localize subdural electrodes and to establish the spatial relationship of each electrode to the underlying brain structure, either normal or damaged, on brain convessity, basal and medial cortex. SIGNIFICANCE: Being simple, rapid, unexpensive, and reliable, this procedure holds promise to be useful to optimize epilepsy surgery planning.

Atypical multiple sclerosis: MRI findings and differential diagnosis.

In the past few years, magnetic resonance imaging (MRI) has become increasingly relevant in the diagnosis of multiple sclerosis (MS). Yet, the specificity of MR is limited. Atypical forms of MS and other diseases of the central nervous system may show similar patterns in MR. We briefly discuss the MR findings of the main MS-like diseases. Correct differential diagnosis can be carried out by combining the MR findings with clinical and laboratory findings.

Multiple spinal meningiomas after tamoxifen therapy: a case report.

We describe a rare case of multiple spinal meningiomas and evaluate the possible relationship with tamoxifen treatment. We observed a 74-year-old woman who showed a spastic paraparesis gradually developed in the last year. The patient underwent left mastectomy for a breast cancer ten years earlier and was treated with tamoxifen for four years after surgical intervention. Magnetic resonance imaging revealed three spinal meningiomas at C6-C7, D6-D7 and D9 levels. Taking in account the tumor-inducing properties of tamoxifen and the extreme rarity of multiple spinal meningiomas, we suggest that tamoxifen may be the cause play a role in the genesis of the spinal meningiomatosis in the observed patient. Therefore, we propose the long-term clinical and neurological surveillance of patients who assumed tamoxifen, even for a short time, in order to survey the possible appearance of secondary tumours.

Real-time MR artifacts filtering during continuous EEG/fMRI acquisition.

The purpose of this study was the development of a real-time filtering procedure of MRI artifacts in order to monitor the EEG activity during continuous EEG/fMRI acquisition. The development of a combined EEG and fMRI technique has increased in the past few years. Preliminary "spike-triggered" applications have been possible because in this method, EEG knowledge was only necessary to identify a trigger signal to start a delayed fMRI acquisition. In this way, the two methods were used together but in an interleaved manner. In real simultaneous applications, like event-related fMRI study, artifacts induced by MRI events on EEG traces represent a substantial obstacle for a right analysis. Up until now, the methods proposed to solve this problem are mainly based on procedures to remove post-processing artifacts without the possibility to control electrophysiological behavior of the patient during fMRI scan. Moreover, these methods are not characterized by a strong "prior knowledge" of the artifact, which is an imperative condition to avoid any loss of information on the physiological signals recovered after filtering. In this work, we present a new method to perform simultaneous EEG/fMRI study with real-time artifacts filtering characterized by a procedure based on a preliminary analytical study of EPI sequence parameters-related EEG-artifact shapes. Standard EEG equipment was modified in order to work properly during ultra-fast MRI acquisitions. Changes included: high-performance acquisition device; electrodes/cap/wires/cables materials and geometric design; shielding box for EEG signal receiver; optical fiber link; and software. The effects of the RF pulse and time-varying magnetic fields were minimized by using a correct head cap wires-locked environment montage and then removed during EEG/fMRI acquisition with a subtraction algorithm that takes in account the most significant EPI sequence parameters. The on-line method also allows a further post-processing utilization.

Cerebellar metabolite alterations detected in vivo by proton MR spectroscopy.

The aim of our work was to evaluate the feasibility of in vivo single-voxel quantitative proton MR spectroscopy in order to identify possible alterations in the main metabolite concentrations due to some metabolic dysfunctions in the cerebellum of patients suffering from a particular form of migraine called "with aura." Measurements of metabolite levels in the cerebellum disclosed reduced choline values (normalized both to N-acetyl-aspartate and creatine) in the patient group with respect to the age-matched control group. Our interest in this pathology is motivated by the fact that there are no available specific biochemical markers for migraine characterization, and the current diagnostic only takes advantage of the medical history and the clinical examination.

BOLD signal sign and transient vessels volume variation.

The purpose of this work was to investigate the relation between BOLD signal sign and transient vessels volume variation induced by apnea. This stimulus consisting of breath holding after inspiration is able to induce a light slowing down in venous blood flow like in a sort of Valsalva maneuver. We observed diffuse negative BOLD responding areas at cortical level and a stronger negative response in correspondence of the main sinuses. These phenomena seem to be unrelated to a specific neural activity, appearing to be expressions of a mechanical variation in the hemodynamics. Our study suggests that particular care must be considered in the interpretation of fMRI findings, especially when patients with vascular-related cerebral diseases are involved.

Use of spiral computerized tomography angiography in patients with cerebral aneurysm. Our experience.

BACKGROUND: The purpose is to highlight the usefulness of CT angiography (CTA) in the diagnosis and surgical treatment of cerebral aneurysms. METHODS: Thirty-one patients with subarachnoid haemorrhages were subjected to CT angiography and in those cases where this test did not reveal the aneurysm or did not supply sufficient information relating to it, subsequently a digital subtraction angiography was also performed. Each aneurysm-positive CTA was re-processed using the 3-D techniques, with the neuro-radiologist and the neuro-surgeon working in close co-operation. RESULTS: In 27 cases the CTA diagnosed an aneurysm, and in the 4 cases where no vascular malformations were revealed, also the traditional angiography did not show any pathology. In 17 out of 18 cases operated on in order to clip the aneurysm, the CTA supplied all the information needed for the surgery and it was possibile to reconstruct images similar to those of the surgical field. This led to improvement in the programming of the surgical intervention; in 1 case only was it also necessary to perform the DSA before the operation. CONCLUSIONS: CT angiography, because it is non-invasive, easy to perform, diagnostically reliable, and because the 3-D re-constructions offer the chance to create images of the possible operating field, is the first-choice test to be adopted in the treatment of subarachnoid haemorrhages, even though in some cases the use of the traditional angiography is still necessary and should be carried out whenever the CTA does not reveal vascular malformations.

Cavernous angiomas of the nervous system in Italy: clinical and genetic study.

We performed a clinical and genetic study of patients affected by cavernous angiomas (CA) of the nervous system. We examined initial signs and symptoms in sporadic and familial cases. We obtained clinical, neuroimaging and genetic data on 15 Italian patients with CA of the nervous system with positive, doubtful or apparently negative family history. Genetic markers surrounding three different gene regions (7q, 3q and 7p) were analysed. In one small family, genetic linkage was consistent with all chromosome loci. In another family with the unusual association of cerebral and spinal CA, linkage with chromosome 7q and, likely, 7p was excluded, while linkage with locus 3q was possible. Our results indicate that Italian families with CA may show genetic heterogeneity. Non-specific and subtle onset symptoms hide the presence of CA within families. Patients with multiple CA may have silent cerebral lesions confirming the low penetrance of clinical signs in spite of radiological ones.

Morphological and functional characteristics of patent foramen ovale and their embolic implications.

BACKGROUND AND PURPOSE: Transesophageal echocardiography (TEE) has detected a high prevalence of patent foramen ovale (PFO) in stroke patients, but the clinical implications of the distinctive characteristics of this patency are still a matter of debate. METHODS: We studied 350 patients with acute ischemic stroke or transient ischemic attack (TIA) within 1 week of admission. Of these, 101 (29%) were identified by contrast TEE to have a PFO; 86 patients (25%) were cryptogenic stroke patients, and 163 were excluded because of the presence of a definite or possible arterial or clinical evidence of a source of emboli or small-vessel disease. Thirteen PFO subjects without a history of embolism were designated as the control group. All PFO and cryptogenic stroke patients were followed up by neurological visits. RESULTS: Compared with controls, PFO patients with acute stroke or TIA more frequently presented with a right-to-left shunt at rest and a higher membrane mobility (P:<0. 05). Patients with these characteristics were considered to be at high risk. During a median follow-up period of 31 months (range, 4 to 58 months), 8 PFO and 18 cryptogenic stroke patients experienced recurrent cerebrovascular events. The cumulative estimate of risk of cerebrovascular event recurrence at 3 years was 4.3% (95% confidence interval [CI], 0% to 10.2%) for "low-risk" PFO patients, 12.5% (95% CI, 0% to 26.1%) for "high-risk" PFO patients, and 16.3% (95% CI, 7. 2% to 25.4%) for cryptogenic stroke patients (high-risk PFO versus low-risk PFO, P:=0.05). CONCLUSIONS: The association of right-to-left shunting at rest and high membrane mobility, as detected by contrast TEE, seems to identify PFO patients with cerebrovascular ischemic events who are at higher risk for recurrent brain embolism.

MRI of spinal cord in MS.

Over the last 10 - 15 years, magnetic resonance imaging techniques have had a major impact in understanding and managing multiple sclerosis. The present review briefly summarises the current usefulness of spinal cord MRI in MS disease, examining the frequency, distribution and main characteristics of spine MS plaques; the differential diagnosis with other spinal cord disease was also described. Finally we considered how newer imaging sequences when added to semi-automated quantitative methods, may give us a putative tool to reliably quantify subtle changes which develop on the spinal cord of MS patients over time.