Statistical Approaches to Identify Pairwise and High-Order Brain Functional Connectivity Signatures on a Single-Subject Basis

Keeping up with the shift towards personalized neuroscience essentially requires the derivation of meaningful insights from individual brain signal recordings by analyzing the descriptive indexes of physio-pathological states through statistical methods that prioritize subject-specific differences under varying experimental conditions. Within this framework, the current study presents a methodology for assessing the value of the single-subject fingerprints of brain functional connectivity, assessed both by standard pairwise and novel high-order measures. Functional connectivity networks, which investigate the inter-relationships between pairs of brain regions, have long been a valuable tool for modeling the brain as a complex system. However, their usefulness is limited by their inability to detect high-order dependencies beyond pairwise correlations. In this study, by leveraging multivariate information theory, we confirm recent evidence suggesting that the brain contains a plethora of high-order, synergistic subsystems that would go unnoticed using a pairwise graph structure. The significance and variations across different conditions of functional pairwise and high-order interactions (HOIs) between groups of brain signals are statistically verified on an individual level through the utilization of surrogate and bootstrap data analyses. The approach is illustrated on the single-subject recordings of resting-state functional magnetic resonance imaging (rest-fMRI) signals acquired using a pediatric patient with hepatic encephalopathy associated with a portosystemic shunt and undergoing liver vascular shunt correction. Our results show that (i) the proposed single-subject analysis may have remarkable clinical relevance for subject-specific investigations and treatment planning, and (ii) the possibility of investigating brain connectivity and its post-treatment functional developments at a high-order level may be essential to fully capture the complexity and modalities of the recovery.

Cognitive outcomes in patients treated with neuromuscular electrical stimulation after coronary artery bypass grafting

Objective

Mechanisms of neurocognitive injury as post-operative sequelae of coronary artery bypass grafting (CABG) are not understood. The systemic inflammatory response to surgical stress causes skeletal muscle impairment, and this is also worsened by immobility. Since evidence supports a link between muscle vitality and neuroprotection, there is a need to understand the mechanisms by which promotion of muscle activity counteracts the deleterious effects of surgery on long-term cognition.

Methods

We performed a clinical trial to test the hypothesis that adding neuromuscular electrical stimulation (NMES) to standard rehabilitation care in post-CABG patients promotes the maintenance of skeletal muscle strength and the expression of circulating neuroprotective myokines.

Results

We did not find higher serum levels of neuroprotective myokines, except for interleukin-6, nor better long-term cognitive performance in our intervention group. However, a greater increase in functional connectivity at brain magnetic resonance was seen between seed regions within the default mode, frontoparietal, salience, and sensorimotor networks in the NMES group. Regardless of the treatment protocol, patients with a Klotho increase 3 months after hospital discharge compared to baseline Klotho values showed better scores in delayed memory tests.

Significance

We confirm the potential neuroprotective effect of Klotho in a clinical setting and for the first time post-CABG.

Statistical Approaches to Characterize Functional Connectivity in Brain and Physiologic Networks on a Single-Subject Basis

The trend toward personalized medicine necessitates drawing conclusions from descriptive indexes of physiopathological states estimated from individual recordings of biomedical signals, using statistical analyses that focus on subject-specific differences between experimental conditions. In this context, the present work introduces an approach to assess functional connectivity in brain and physiologic networks by pairwise information-theoretic measures of coupling between signals, whose significance and variations between conditions are statistically validated on a single-subject basis through the use of surrogate and bootstrap data analyses. The approach is illustrated on single-subject recordings of (i) resting-state functional magnetic resonance imaging (rest-fMRI) signals acquired in a pediatric patient with hepatic encephalography associated to a portosystemic shunt and undergoing liver vascular shunt correction, and of (ii) cardiovascular and cerebrovascular time series acquired at rest and during head-up tilt in a subject suffering from orthostatic intolerance.

Imaging of hepatocellular carcinoma recurrence after liver transplantation

Liver transplantation (LT) provides the highest survival benefit to patients with unresectable hepatocellular carcinoma (HCC). The Milan criteria have been developed for the selection of LT candidates with the goal of improving survival and maintaining an acceptable risk of HCC recurrence. Despite this, recurrence of HCC after LT occurs in up to 20% of cases and represents a major concern due to the poor prognosis of these patients. Furthermore, several extended criteria for the selection of LT candidates have been proposed to account for the growing demand for organs and the resultant increase in the risk of HCC recurrence. Radiologists should be aware that HCC can recur after LT with multiple organ involvement. Knowledge of the location and radiologic appearance of recurrent HCC is necessary to ensure the choice of the most appropriate therapy. This paper aims to comprehensively summarize the spectrum of HCC recurrence after LT and to examine and discuss the imaging features of these lesions. CRITICAL RELEVANCE STATEMENT: This paper aims to share a review of imaging findings of HCC recurrence after LT and to make radiologists familiar with the spectrum of this disease.

Neurological Screening in Elderly Liver Transplantation Candidates: A Single Center Experience

Background: Cerebral small vessels disease (cSVD) is an age-related disorder and risk factor for stroke and cognitive/motor impairments. Neurological complications (NCs) are among the causes of adverse outcomes in older liver transplant recipients. This study sought to determine whether cSVD predicts acute NCs in over 65-year-old liver transplant patients. Methods: Data were collected, from a retrospective medical chart review, of 22 deceased donor liver transplant recipients aged 65 years or older with a pre-operative brain magnetic resonance imaging (MRI). We used the Fazekas score (0–3) as a quantitative measurement of the vascular lesion load seen in the MRI. We analyzed all post-operative acute NCs occurring during the hospital stay and any other non-NC. Results: cSVD was recognized in all patients. Neurological complications (NCs) occurred in 18.1% of patients with toxic-metabolic encephalopathy the most frequent diagnosis (13.64%). More severe cSVD was associated with seizures (p = 0.0362), longer hospital stay (p 0.0299), and disability (p 0.0134). In our elderly cohort, hepatic encephalopathy (HE) (p 0.0287) and ascites (p 0.0270) were predictors of NCs after liver transplantation. Ascites and/or variceal bleeding and severity of liver disease were associated with adverse post-operative outcomes. The small sample size limited the statistical analysis power. Conclusions: We present the preliminary data of a single-center retrospective study aimed at understanding the cSVD role on NCs and non-NCs after a liver transplantation in elderly patients. This would encourage a more appropriate multicenter prospective study that will definitely confirm if a neurological screening in old age liver transplant candidates is appropriate.

Imaging of calcified hepatic lesions: spectrum of diseases

Hepatic calcifications have been increasingly identified over the past decade due to the widespread use of high-resolution Computed Tomography (CT) imaging. Calcifications can be seen in a vast spectrum of common and uncommon diseases, from benign to malignant, including cystic lesions, solid neoplastic masses, and inflammatory focal lesions. The purpose of this paper is to present an updated review of CT imaging findings of a wide range of calcified hepatic focal lesions, which can help radiologists to narrow the differential diagnosis.

Temperature Measurement by Diffusion-Weighted Imaging

Diffusion-weighted imaging (DWI) thermometry is a magnetic resonance-based imaging tool that allows the noninvasive measurement of brain core temperature. Although only applicable to cerebrospinal fluid, it is thought to be potentially useful in assessing the thermal pathophysiology of the brain in both patients and healthy subjects. The objective of this article is to provide a concise but thorough review of the basic physical principles and the principal applications of DWI thermometry as a potential method to elucidate the pathophysiology of several brain diseases and neurologic syndromes.

Multiple sclerosis: prevalence of the 'central vein' sign in white matter lesions on gadolinium-enhanced susceptibility-weighted images

AIMS

To evaluate prospectively whether an intravenous gadolinium injection could improve the detection of the central vein sign on susceptibility-weighted imaging sequences obtained with a 1.5 T magnetic resonance scanner in patients with multiple sclerosis compared to unenhanced susceptibility-weighted images.

MATERIALS AND METHODS

This prospective, institution review board-approved study included 19 patients affected by multiple sclerosis (six men; 13 women; mean age 40.8 years, range 20-74 years). Patients had the relapsing-remitting clinical subtype in 95% of cases, and only one (5%) patient had the primary progressive clinical subtype of multiple sclerosis. T2-weighted images, fluid-attenuated inversion recovery images, unenhanced and contrast-enhanced susceptibility-weighted images were evaluated in consensus by two neuroradiologists for the presence of the central vein sign. The readers were blinded to magnetic resonance imaging reports, clinical information, the presence and the localisation of focal hyperintense white matter lesions. Any discordance between readers was resolved through a joint review of the recorded images with an additional neuroradiologist.

RESULTS

A total of 317 multiple sclerosis lesions were analysed. The central vein sign had a higher prevalence detection rate on gadolinium-enhanced susceptibility-weighted images (272 of 317 lesions, 86%) compared to unenhanced susceptibility-weighted images (172 of 317 lesions, 54%).

CONCLUSION

Gadolinium-enhanced susceptibility-weighted imaging improves the detection rate of the central vein sign in multiple sclerosis lesions.

Seizure in isolated brain cryptococcoma: Case report and review of the literature

Background:

Central nervous system (CNS) cryptococcosis is an invasive fungal infection predominantly seen among immunosuppressed patients causing meningitis or meningoencephalitis. Rarely, cryptococcosis can affect immunologically competent hosts with the formation of localized CNS granulomatous reaction, known as cryptococcoma. Common symptoms of CNS cryptococcoma are headaches, consciousness or mental changes, focal deficits, and cranial nerve dysfunction. Rarely, seizures are the only presenting symptom.

Case Description:

We report the case of an immunocompetent patient with a solitary CNS cryptococcoma presenting with a long history of non-responsive generalized seizure who has been successfully operated.

Conclusion:

CNS cryptococcoma is a rare entity, and in immunocompetent patients, its diagnosis can be challenging. The pathophysiology of lesion-related seizure is discussed along with a review of the pertinent literature.

Role of non-coding RNAs in age-related vascular cognitive impairment: An overview on diagnostic/prognostic value in Vascular Dementia and Vascular Parkinsonism

Age is the pivotal risk factor for different common medical conditions such as cardiovascular diseases, cancer and dementia. Among age-related disorders, cardiovascular and cerebrovascular diseases, represent the leading causes of premature mortality strictly related to vascular ageing, a pathological condition characterized by endothelial dysfunction, atherosclerosis, hypertension, heart disease and stroke. These features negatively impact on the brain, owing to altered cerebral blood flow, neurovascular coupling and impaired endothelial permeability leading to cerebrovascular diseases (CVDs) as Vascular Dementia (VD) and Parkinsonism (VP). It is an increasing opinion that neurodegenerative disorders and cerebrovascular diseases are associated from a pathogenetic point of view, and in this review, we discuss how cerebrovascular dysfunctions, due to epigenetic alterations, are linked with neuronal degeneration/dysfunction that lead to cognitive impairment. The relation between neurodegenerative and cerebrovascular diseases are reviewed with a focus on role of ncRNAs in age-related vascular diseases impairing the endothelium in the blood-brain barrier with consequent dysfunction of cerebral blood flow. In this review we dissert about different regulatory mechanisms of gene expression implemented by ncRNAs in the pathogenesis of age-related neurovascular impairment, aiming to highlight the potential use of ncRNAs as biomarkers for diagnostic/prognostic purposes as well as novel therapeutic targets.

Outcome of LR-3 and LR-4 observations without arterial phase hyperenhancement at Gd-EOB-DTPA-enhanced MRI follow-up

OBJECTIVE

The aim of this study was to retrospectively analyze the outcome of LR-3 and LR-4 without arterial phase hyperenhancement (APHE), and identify which features could predict LR-5 progression on serial Gd-EOB-DTPA-enhanced MRI follow-up.

METHODS

Forty-nine cirrhotic patients with 55 LR-3 and 19 LR-4 without APHE were evaluated. Observations were classified as decreased, stable or increased in category at follow-up. Observation size and LI-RADS major and ancillary features were evaluated.

RESULTS

Seventeen/fifty-five (31%) LR-3 and 8/19 (42%) LR-4 progressed to LR-5 at follow-up. Baseline LI-RADS major and ancillary features were not significantly different among LR-3 and LR-4. A diameter ≥ 10 mm significantly increased LR-5 progression risk of LR-3 (OR = 6.07; 95% CI: 0.12; 60.28]; P < .001). LR-4 with a diameter ≥ 10 mm more likely become LR-5 at follow-up (OR = 8.95; 95% CI: 0.73; 111.8; P = .083]).

CONCLUSION

LR-3 and LR-4 without APHE were often downgraded or remained stable in category on Gd-EOB-DTPA-enhanced MRI follow-up.

Resting-State Functional Connectome in Patients with Brain Tumors Before and After Surgical Resection

PURPOSE

High-grade glioma surgery has evolved around the principal belief that a safe maximal tumor resection improves symptoms, quality of life, and survival. Mapping brain function has been recently improved by resting-state functional magnetic resonance imaging (rest-fMRI), a novel imaging technique that explores networks connectivity at "rest."

METHODS

This prospective study analyzed 10 patients with high-grade glioma in whom rest-fMRI connectivity was assessed both in single-subject and in group analysis before and after surgery. Seed-based functional connectivity analysis was performed with CONN toolbox. Network identification focused on 8 major functional connectivity networks. A voxel-wise region of interest (ROI) to ROI correlation map to assess functional connectivity throughout the whole brain was computed from a priori seeds ROI in specific resting-state networks before and after surgical resection in each patient.

RESULTS

Reliable topography of all 8 resting-state networks was successfully identified in each participant before surgical resection. Single-subject functional connectivity analysis showed functional disconnection for dorsal attention and salience networks, whereas the language network demonstrated functional connection either in the case of left temporal glioblastoma. Functional connectivity in group analysis showed wide variations of functional connectivity in the default mode, salience, and sensorimotor networks. However, salience and language networks, salience and default mode networks, and salience and sensorimotor networks showed a significant correlation (P uncorrected <0.0025; P false discovery rate <0.077) in comparison before and after surgery confirming non-disconnection of these networks.

CONCLUSIONS

Resting-state fMRI can reliably detect common functional connectivity networks in patients with glioma and has the potential to anticipate network alterations after surgical resection.

CT and MR imaging of cystic renal lesions

Cystic renal lesions are a common incidental finding on routinely imaging examinations. Although a benign simple cyst is usually easy to recognize, the same is not true for complex and multifocal cystic renal lesions, whose differential diagnosis includes both neoplastic and non-neoplastic conditions. In this review, we will show a series of cases in order to provide tips to identify benign cysts and differentiate them from malignant ones.

Advanced magnetic resonance imaging of cortical laminar necrosis in patients with stroke

PURPOSE

The aim of this study was to assess the novel advanced magnetic resonance imaging findings of acute stage cortical laminar necrosis developing after complicated cardiovascular or abdominal surgery.

MATERIALS AND METHODS

This institutional review board-approved study included patients with postoperative stroke due to cortical laminar necrosis imaged with magnetic resonance in the acute stage. Brain magnetic resonance imaging examinations were obtained on a 3T magnetic resonance scanner within 48 hours of the neurological symptoms, including diffusion-weighted images (b value, 1000 s/mm²) and arterial spin labelling using a pseudo-continuous arterial spin labelling method in four patients. Conventional and advanced magnetic resonance images were analysed to assess the imaging features in acute stage cortical laminar necrosis.

RESULTS

The final population consisted of 14 patients (seven men and seven women, mean age 61 years, range 32-79 years) diagnosed with stroke and acute phase cortical laminar necrosis. All the patients presented with cortical lesions showing restricted diffusion on diffusion-weighted images and hypointensity on the apparent diffusion coefficient map. Cortical hyperintensity on T2-weighted or fluid-attenuated inversion recovery images was found in three (21%) and six (43%) patients, respectively. Reduced perfusion was noted in three out of four patients imaged with arterial spin labelling, while in one case no corresponding perfusion abnormality was noted on the arterial spin labelling maps. Arterial spin labelling abnormalities were much more extensive than diffusion restriction in two patients, and they were associated with a poor outcome.

CONCLUSION

Cortical hyperintense abnormalities on diffusion-weighted imaging may be the only sign of developing cortical laminar necrosis injury. The acquisition of arterial spin labelling helps to identify perfusion alterations and the extension of the ischaemic injury.

Guillain-Barré syndrome after orthotopic liver transplantation: A clinical manifestation of immune reconstitution inflammatory syndrome?

Guillain-Barrè Syndrome, as part of the spectrum of dysimmune neuropathies, is unexpected to occur in immunocompromised hosts. We describe a clinical case of Guillain-Barrè syndrome, occurred a few weeks after a liver transplant, and we postulate that our case would satisfy all requirements to explain this peripheral nervous system complication as a clinical manifestation of an Immune reconstitution inflammatory syndrome. In this setting of liver transplantation, complicated by potentially multiple infective triggers, reduction of immunosuppression and reversal of pathogen-induced immunosuppression, through antimicrobial therapy, may have led to pro-inflammatory response. The pro-inflammatory pattern would have sustained the pathophysiologic mechanism of this immune neuropathy.

A rare case of ruptured aneurysm of the paramedian artery of Percheron

Introduction The artery of Percheron is a rare anatomic variant supplying bilateral medial thalamic nuclei and a variable portion of the rostral part of midbrain. Case report A 48-year-old female with massive subarachnoid hemorrhage due to a ruptured aneurysm of the paramedian artery of Percheron presented to the emergency room. Because of significant risk of recurrent intracranial hemorrhage, it was decided to proceed with endovascular embolization of the aneurysm. The patient was ultimately sent to a rehabilitation center and her presenting neurologic deficits showed significant improvements in the weeks following endovascular embolization treatment. Discussion The paramedian artery of Percheron is a rare anatomic variant and subarachnoid hemorrhage due to aneurysm of this artery is exceedingly rare. This case underlines the importance of a correct evaluation of cerebral arterial anatomy in order to choose the best endovascular therapeutic approach, reduce complications, and optimize patient outcome.

Multiple sclerosis: High prevalence of the 'central vein' sign in white matter lesions on susceptibility-weighted images

Purpose The aim of this study was to determine the occurrence and distribution of the 'central vein' sign in white matter lesions on susceptibility-weighted magnetic resonance images in patients with multiple sclerosis (MS) and cerebral small vessel disease (CSVD). Materials and methods T2-weighted and fluid-attenuated inversion recovery magnetic resonance images of 19 MS patients and 19 patients affected by CSVD were analysed for the presence and localisation of focal hyperintense white matter lesions. Lesions were subdivided into periventricular or non-periventricular (juxtacortical, subcortical, deep white matter and cerebellar) distributed. The number and localisation of lesions presenting with the central vein sign were recorded and compared between MS and CSVD lesions. Results A total of 313 MS patients and 75 CSVD lesions were identified on T2-weighted and fluid-attenuated inversion recovery magnetic resonance images. The central vein sign was found in 128 MS lesions (40.9%), and the majority of them (71/128, 55.5%) had a periventricular distribution. The central vein sign was found in 22 out of 75 (29.3%) CSVD lesions, and periventricular distribution was seen in six out of 22 (27.2%) CSVD lesions. The difference in the proportion of white matter hyperintense lesions that presented with the central vein sign on susceptibility-weighted images in patients with MS and CSVD was statistically different, and a significantly higher number of MS patients presented with lesions with the central vein sign compared to CSVD patients. Conclusion The presence of the central vein sign on susceptibility-weighted images for MS lesions improves the understanding of the periventricular distribution of MS lesions and could contribute as adjunctive diagnostic criteria for MS disease.

Evolution of indeterminate hepatocellular nodules at Gd-EOB-DPTA-enhanced MRI in cirrhotic patients

PURPOSE

To retrospectively analyze the evolution of indeterminate hepatocellular nodules in cirrhotic patients on serial Gd-EOB-DPTA-enhanced MRI, and to identify predictors of HCC development.

MATERIALS AND METHODS

This IRB approved study included 33 cirrhotic patients with 69 indeterminate hepatocellular nodules (mean diameter 1.1 cm) at baseline Gd-EOB-DPTA-enhanced MRI and a Gd-EOB-DPTA-enhanced-MRI follow-up of at least 2 years. Two radiologists evaluated size and signal intensity of each nodule at baseline and follow-up. Age, cirrhosis etiology, and HCC history were recorded. Data were compared between nodules that became HCCs at follow-up (HCC) and those that did not (no-HCC).

RESULTS

On follow-up, 5/69 nodules became HCCs and 64/69 showed indeterminate characteristics. HCC history was more frequently found in HCCs than in no-HCCs. Age, sex, and cirrhosis etiology were not significantly different between HCCs and no-HCCs. HCCs had a significantly greater baseline diameter and increase in size than no-HCCs. Hepatobiliary phase hypointensity was significantly more common in HCCs than in no-HCCs. Multivariate regression analysis showed that increase in size (OR 10.48; sensitivity, 100%; specificity, 81.2%; p < 0.001) and hepatobiliary phase hypointensity (OR 1.02; sensitivity, 100%; specificity, 78.1%; p < 0.001) was associated with HCC development.

CONCLUSION

Indeterminate hepatocellular nodules at Gd-EOB-DPTA-enhanced MRI in cirrhotic patients rarely became HCCs. Hepatobiliary phase hypointensity had a weak association with HCC development.

Computerised tomography and magnetic resonance imaging of laryngeal squamous cell carcinoma: A practical approach

Squamous cell carcinoma is the most common head and neck cancer. This review describes the state-of-the-art computerised tomography and magnetic resonance imaging protocols of the neck and the normal larynx anatomy, and provides a practical approach for the diagnosis and staging of laryngeal squamous cell carcinoma.

Assessment of cerebral microbleeds by susceptibility-weighted imaging in Alzheimer's disease patients: A neuroimaging biomarker of the disease

Purpose The objective of this study was to correlate the presence and distribution of cerebral microbleeds in Alzheimer's disease patients with cerebrospinal fluid biomarkers (amyloid-beta and phosphorylated tau 181 protein levels) and cognitive decline by using susceptibility-weighted imaging magnetic resonance sequences at 1.5 T. Material and methods Fifty-four consecutive Alzheimer's disease patients underwent brain magnetic resonance imaging at 1.5 T to assess the presence and distribution of cerebral microbleeds on susceptibility-weighted imaging images. The images were analyzed in consensus by two neuroradiologists, each with at least 10 years' experience. Dementia severity was assessed with the Mini-Mental State Examination score. A multiple regression analysis was performed to assess the associations between the number and location of cerebral microbleed lesions with the age, sex, duration of the disease, cerebrospinal fluid amyloid-beta and phosphorylated tau 181 protein levels, and cognitive functions. Results A total of 296 microbleeds were observed in 54 patients; 38 patients (70.4%) had lobar distribution, 13 patients (24.1%) had non-lobar distribution, and the remaining three patients (5.6%) had mixed distribution, demonstrating that Alzheimer's disease patients present mainly a lobar distribution of cerebral microbleeds. The age and the duration of the disease were correlated with the number of lobar cerebral microbleeds ( P < 0.001). Cerebrospinal fluid amyloid-beta, phosphorylated tau 181 protein levels, and cognitive decline were correlated with the number of lobar cerebral microbleeds in Alzheimer's disease patients ( P < 0.001). Conclusion Lobar distribution of cerebral microbleeds is associated with Alzheimer's disease and the number of lobar cerebral microbleeds directly correlates with cerebrospinal fluid amyloid-beta and phosphorylated tau 181 protein levels and with the cognitive decline of Alzheimer's disease patients.

Magnetic resonance imaging in the assessment of brain involvement in alcoholic and nonalcoholic Wernicke’s encephalopathy

AIM

To present the typical and atypical magnetic resonance (MR) imaging findings of alcoholic and non-alcoholic Wernicke’s encephalopathy.

METHODS

This study included 7 patients with Wernicke’s encephalopathy (2 men, 5 women; mean age, 52.3 years) that underwent brain MR examination between January 2012 and March 2016 in a single institution. Three patients were alcoholics and 4 patients were non-alcoholics. MR protocol included a T2-weighted sequence, a fluid attenuation inversion recovery (FLAIR) sequence, a diffusion-weighted sequence (b = 0 and 1000 s/mm²), and a contrast-enhanced MR sequence. All MR images were retrospectively reviewed at baseline and follow-up by two radiologists.

RESULTS

All patients with Wernicke’s encephalopathy had bilateral areas showing high signal intensity on both T2-weighted and FLAIR MR images in the typical sites (i.e., the periaqueductal region and the tectal plate). Signal intensity abnormalities in the atypical sites (i.e., the cerebellum and the cerebellar vermis) were seen in 4 patients, all of which had no history of alcohol abuse. Six patients had areas with restricted diffusion in the typical and atypical sites. Four patients had areas showing contrast-enhancement in the typical and atypical sites. Follow-up MR imaging within 6 mo after therapy (intravenous administration of thiamine) was performed in 4 patients, and demonstrated a complete resolution of all the signal intensities abnormalities previously seen in all patients.

CONCLUSION

MR imaging is valuable in the diagnosis of Wernicke’s encephalopathy particularly in patients presenting with atypical clinical symptoms, or with no history of alcohol abuse.

Diagnostic performance of reformatted isotropic thin-section helical CT images in the detection of superior semicircular canal dehiscence

Purpose The purpose of this article is to assess the diagnostic performance of computed tomography (CT) reformatted images for detection of superior semicircular canal (SSC) dehiscence. Material and methods Forty-two patients, with sound- and/or pressure-induced vestibular symptoms, and 42 control participants underwent helical CT examination with a highly collimated beam (0.5 mm). Reformatted images of the vestibular labyrinth were obtained in the standard axial and coronal planes (group A images), and in a plane parallel and perpendicular to the SSC (group B images). Diagnostic performance obtained by evaluating the group A images alone and the group B images alone was analyzed by using the area under the receiver operating characteristic curve (AUC). Results The diagnostic performance of group A images was AUC = 0.929 with an overall accuracy of 92.9%. The diagnostic performance of group B images was AUC = 0.988 with an overall accuracy of 98.8%. The evaluation of group B images alone showed an improved diagnostic performance over the group A images alone. Conclusion Thin-section 0.5-mm collimation CT with reformatted images oriented in the plane parallel and perpendicular to the SSC improves diagnostic accuracy in assessing for SSC dehiscence in comparison to CT images with reconstructions limited to traditional axial and coronal planes.

Value of serial magnetic resonance imaging in the assessment of brain metastases volume control during stereotactic radiosurgery

AIM

To evaluate brain metastases volume control capabilities of stereotactic radiosurgery (SRS) through serial magnetic resonance (MR) imaging follow-up.

METHODS

MR examinations of 54 brain metastases in 31 patients before and after SRS were reviewed. Patients were included in this study if they had a pre-treatment MR examination and serial follow-up MR examinations at 6 wk, 9 wk, 12 wk, and 12 mo after SRS. The metastasis volume change was categorized at each follow-up as increased (> 20% of the initial volume), stable (± 20% of the initial volume) or decreased (< 20% of the initial volume).

RESULTS

A local tumor control with a significant (P < 0.05) volume decrease was observed in 25 metastases at 6-wk follow-up. Not significant volume change was observed in 23 metastases and a significant volume increase was observed in 6 metastases. At 9-wk follow-up, 15 out of 25 metastases that decreased in size at 6 wk had a transient tumor volume increase, followed by tumor regression at 12 wk. At 12-wk follow-up there was a significant reduction in volume in 45 metastases, and a significant volume increase in 4 metastases. At 12-mo follow-up, 19 metastases increased significantly in size (up to 41% of the initial volume). Volume tumor reduction was correlated to histopathologic subtype.

CONCLUSION

SRS provided an effective local brain metastases volume control that was demonstrated at follow-up MR imaging.

Accuracy of SWI sequences compared to T2*-weighted gradient echo sequences in the detection of cerebral cavernous malformations in the familial form

PURPOSE

The purpose of this study was to assess the accuracy of susceptibility-weighted imaging (SWI), compared with T2*-weighted gradient echo (GRE) imaging in assessing cerebral cavernous malformations.

MATERIALS AND METHODS

We retrospectively evaluated 21 patients with a familial form of cavernous malformation. Magnetic resonance (MR) protocol included non-enhanced and contrast-enhanced fast-spin echo (FSE) T1-weighted sequences, FSE T2-weighted sequences, fluid-attenuated inversion-recovery (FLAIR), GRE T2*-weighted and SWI sequences. Images were reviewed in consensus by two expert neuroradiologists to assess the location, number, size and conspicuity of the lesions on T2*-weighted GRE and SWI sequences. Statistical differences in the number, size and conspicuity of the lesions seen on the SWI images and the T2*-weighted GRE images were assessed with the nonparametric Wilcoxon signed rank test.

RESULTS

The number of cavernous malformations was significantly higher (p < .001) on the SWI images (n = 152) than on T2*-weighted GRE images (n = 56). Lesion size was significantly higher (p < .001) on SWI images (mean: 0.4 cm, SD ± 0.55) than on T2*-weighted GRE sequences (mean: 0.2 cm, SD ± 0.51) and the differences were statistically significant (p < .001). Lesion conspicuity was significant higher (p < .001) on SWI than on T2*-weighted GRE images. In one patient who underwent a 2-month follow-up for the onset of neurologic symptoms related to cerebral hemorrhage, a cerebral hematoma was identified at the site of a cerebral cavernous malformation that was demonstrated only on the SWI images in the previous MR examination.

CONCLUSIONS

The SWI sequence, being more sensitive to substances which distort the local magnetic field than the GRE T2*W sequence, showed a higher sensitivity in identifying cerebral cavernous malformations. Thus, routine clinical neuroimaging protocol should contain SWI sequences to evaluate patients with (or suspected) cerebral cavernous malformations.

Computed tomography of bowel obstruction: tricks of the trade

Bowel obstruction (BO) is a frequent cause of hospitalization and surgical consultation for acute abdominal pain. It is usually suspected at physical examination, but clinical and laboratory data are often nonspecific. Thus, computed tomography plays a crucial role in a correct diagnosis of BO. Indeed, computed tomography can confirm a diagnosis of BO, and identify the location and cause of the obstruction. In this review, the computed tomography appearances of common and uncommon causes of BO and pseudo-obstruction are reviewed.

Usefulness of quantitative peritumoural perfusion and proton spectroscopic magnetic resonance imaging evaluation in differentiating brain gliomas from solitary brain metastases

OBJECTIVES

The purpose of our study was to evaluate whether peritumoural perfusion weighted and proton spectroscopic magnetic resonance imaging can be used in differentiating between primary gliomas and solitary metastases.

METHODS

Ten low-grade gliomas, eight high-grade gliomas and 10 metastases were prospectively evaluated with magnetic resonance imaging, dynamic susceptibility contrast enhanced perfusion imaging and single-voxel proton magnetic resonance spectroscopy before surgical resection or stereotactic biopsy. Maximal relative cerebral blood volume values were calculated drawing three regions of interest of 2 cm(2) in the non-enhancing peritumoural areas. Maximal relative cerebral blood volume values were normalised to that of contralateral normal-appearing white matter. Maximal choline/creatine ratios were calculated from three voxels of 10 cm(3) placed in the peritumoural areas defined as non-enhancing peritumoural white matter surrounding the tumour. The tumour grade presumed with these values was compared to histopathological grading. Differences in the study parameters between groups were assessed using the Mann-Whitney test. A receiver operating characteristic analysis was performed to determine cut-off values.

RESULTS

A clear relative cerebral blood volume cut-off value of 1.88 was detected for differentiating low-grade gliomas from high-grade gliomas. A clear relative cerebral blood volume cut-off value of 1.20 was detected for differentiation of metastases from gliomas. The differences in the choline/creatine ratios in the peritumoural regions of high-grade gliomas and of solitary metastasis were statistically significant (P < 0.001) but a clear cut-off value was not found.

CONCLUSION

Our preliminary data support the hypothesis that peritumoural perfusion-weighted imaging can assist in preoperative differentiation between a glioma and a solitary metastasis.

MR Imaging of Bilateral Paramedian Thalamic and Mesencephalic Infarcts. A Case Report

We describe MR imaging of bilateral infarction of the paramedian portion of the mesencephalus and thalamus due to an occlusion of the Percheron artery. This entity is due to one of the anatomic variants of the perforating arteries supplying the thalamus and mesenchephalus. Clinically this kind of infarction presents with neurologic impairment as a disorder of consciousness, memory dysfunctions, various types of vertical gaze palsy and psychic changes, which need to be differentiated from delirium and coma. At MRI evaluation infarction of the paramedian portion of thalami and midbrain, with a "butterfly wings" pattern, was demonstrated as high signal intensity areas on FLAIR and FSE-T2W images and with diffusion restriction on DWI images.

Imaging processing for CT angiography of the cervicocranial arteries: evaluation of reformatting technique

PURPOSE

The aim of this study was to compare computed tomography angiography (CTA) sliding-thin-slab (STS) multiplanar reformatting (MPR), STS maximum intensity projection (MIP) and three-dimensional (3D) volume rendering (VR) reformatting techniques in the evaluation of cervicocranial arteries.

MATERIALS AND METHODS

Twenty patients examined with multislice CT were included in this study. CTA images were reformatted as STS-MIP, STS-MPR and 3DVR in orthogonal planes and in the oblique-coronal plane. Images were evaluated in consensus by two radiologists, with a third radiologist to resolve discordances in grading image quality parameters. The Spearman correlation analysis was performed to compare results and to obtain the correlation between scores resulting from the evaluation of parameters considered with the different techniques used (STSMIP, STS-MPR and 3DVR).

RESULTS

STS-MIP images were significantly superior to STSMPR images for all parameters considered (p<0.05). Obliquecoronal 3DVR images were significantly superior to obliquecoronal STS-MIP images in the evaluation of vertebrobasilar vessels (p<0.05); in all other cases, 3DVR images were equivalent to STS-MIP images.

CONCLUSION

STS-MIP images should be the primary reformatting technique for CTA of the cervicocranial arteries in addition to viewing the source images; 3DVR images can play an important role after a previsional diagnosis is made on the STS-MIP images.

Initial Experiences in Radiology e-Learning

The use of two different educator-centric learning management systems (LMSs), Moodle and Manila, for radiology e-learning was formatively evaluated and the implications of the future use of LMSs in radiology education were explored. NeuroRAD, a neuroradiologic digital library and learning community, is implemented with Moodle, one of the most popular open-source educator-centric LMSs. Pediatric-Education.org, a pediatric digital library and learning community, is implemented with Manila, a commercial educator-centric LMS. Quantitative and qualitative analyses of these LMSs were performed with World Wide Web server log file statistical programs and user-submitted comment forms. In 2005, NeuroRAD was used by 9959 visitors, who read 98,495 pages of information, whereas PediatricEducation .org was used by 91,000 visitors, who read 186,000 pages of information. Visitors represented a wide spectrum of medical learners and used the sites to answer clinical questions; to prepare for lectures, conferences, and informal teaching sessions; and to stay up-to-date and prepare for examinations. Early results indicate that radiology learning communities can be implemented with educator-centric LMSs relatively easily and at low cost by radiologists with minimal computer expertise, and can find receptive and appreciative audiences. Online radiology learning communities could play a significant role in providing education to radiologists the world over throughout their careers.

Perfusion CT in acute stroke: predictive value of perfusion parameters in assessing tissue viability versus infarction

PURPOSE

The aim of this study was to assess the value of computed tomography (CT) perfusion parameters in differentiating tissue viability in acute stoke patients.

MATERIALS AND METHODS

Thirteen patients (mean age 63.3 years) with nonhaemorrhagic stroke underwent multidetector perfusion CT within 3 h of symptom onset. Images were continuously acquired at the basal ganglia over 40 s during injection of 90 ml of iodinated contrast medium injected at a rate of 9 ml/s with a 9-s delay. Z-axis coverage was 20 mm. All patients underwent diffusion-weighted magnetic resonance imaging (DWI) within 12 h of perfusion CT to define the extent of the infarct. Perfusion CT data were analysed in regions of interests (ROIs) on regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF) and mean transit time (MTT) maps placed in various parts of the perfusion-deficient territory and in the contralateral hemisphere. Statistical analysis was performed using the analysis of variance (ANOVA) test to assess differences in CT perfusion parameters. Receiver operator characteristics (ROC) analysis was performed to assess possible threshold values that predict tissue infarction vs. viability.

RESULTS

Normal CT findings with abnormal CT perfusion parameters were seen in the region of infarction and in the viable tissue (penumbra) within a 1.5-cm distance from the infarct margin as outlined on DWI images. Infarcted areas demonstrated significant prolongation of MTT values compared with noninfarcted areas (p<0.0001). Average MTT was 9.8 s in areas of infarction, 5.1 s in the viable tissue adjacent to the infarct (penumbra), and 3.4 s in the contralateral control area. An MTT threshold level of 6.05 s has a 100% positive predictive value (sensitivity 84.6%, specificity 100%, accuracy 92.3%) for the presence of infarcted tissue. Average rCBF was 24.6 ml/100 g per min in infarcted tissue, 64.8 in penumbra and 70.8 in normal tissue. Average rCBV was 3.5 ml/100g in infarcted tissue, 3.9 in penumbra and 2.9 in normal tissue.

CONCLUSIONS

Prolongation of MTT was the most frequent CT perfusion finding observed in acute stroke patients. Average MTT values of 5.1 s may distinguish viable tissue, whereas MTT values >6.05 s identify infarcted tissue.

Gastrointestinal stromal tumour: 40-row multislice computed tomography findings

PURPOSE

The purpose of this study was to describe the findings and evaluate the role of multidetector (40-slice) computed tomography (MDCT) in the preoperative assessment of gastrointestinal stromal tumours (GISTs).

MATERIALS AND METHODS

Thirteen patients with histologically proven GIST (size: 4-30 cm; mean: 9 cm) underwent 40-slice MDCT after the ingestion of 1,000 ml of water. Images were obtained before and 70 s after intravenous injection of 120 ml of iodinated contrast agent. Two experienced radiologists reviewed the CT findings to evaluate lesion site, size, margins, attenuation, growth pattern, enhancement pattern, ascites, lymphadenopathy, direct invasion to adjacent organs and distant metastasis. Multiplanar maximum intensity projection and three-dimensional (3D) reconstructions were also obtained.

RESULTS

Seven out of 13 GISTs were located in the jejunumileum, 3/13 in the stomach, 2/13 in the rectum and in one case, the origin remained unknown. Eleven out of 13 were exophytic, and ten had well-defined borders. Two out of 13 showed calcifications. Thirteen out of 13 exhibited inhomogeneous enhancement due to areas of necrosis and cystic degeneration. Direct invasion to adjacent organs (n=3), ascites (n=3), and liver (n=1) and peritoneal (n=1) metastases were also detected. Bowel obstruction, vascular invasion and lymphadenopathy were never seen.

CONCLUSIONS

MDCT allowed reliable preoperative assessment of GIST, providing useful clues for lesion characterisation.

[Development of a low-cost DICOM-server for teaching and research purposes]

PURPOSE

This paper describes our experience in developing a DICOM (Digital Imaging and Communications in Medicine) server based on widely available personal computers enabling to use X-ray digital images for teaching and scientific purposes.

MATERIALS AND METHODS

The system is based on a DICOM server running on a widely used personal computer. The selected DICOM images are collected directly from the radiological equipment or from a dedicated 3D image processing workstation through a LAN connection and converted into one of the standard formats (JPEG or GIF) to allow their direct importing into multimedia presentations for teaching or scientific purposes.

RESULTS

This system allows fast and easy collection of radiological images in DICOM format directly from the diagnostic equipment or from the graphical workstation. These images may be used for scientific and teaching presentations without loss of image quality and colour characteristics in 3D images as there is no off-line acquisition process.

CONCLUSIONS

The extensive possibilities of implement the system described on widely used PCs makes the system extremely versatile and facilitates the preparation of teaching material and scientific publications.

Prognostic value of hyperattenuating middle cerebral artery sign at CT in cerebral infarction

PURPOSE

To assess the prognostic value of hyperattenuating middle cerebral artery sign at CT in acute cerebral infarction.

MATERIALS AND METHODS

Ninety-two patients with acute cerebral infarction in the sylvian area were retrospectively reviewed. All patients underwent unenhanced CT 12-24 hours after the onset of symptoms and follow-up CT within 48-72 hours. Initial CT scans were evaluated by consensus by three radiologists to confirm or exclude the presence of hyperattenuating middle cerebral artery sign. History, cardiovascular risk factors and neurological impairment at discharge (mean 25 days) were recorded for each patient. The degree of disability was graded 0 (no disability) to 6 (death). Patients were divided into two groups: patients without (group A) and patients with (group B) hyperattenuating middle cerebral artery sign. A logistic regression analysis was performed to compare the two groups. Results were correlated with cardiovascular risk factors. Kaplan-Meier survival curves were calculated for each group.

RESULTS

Hyperattenuating middle cerebral artery sign was present in 18 patients (19.6%) (group B). The percentage of neurological deficits was significantly higher in group B than in group A (p<0.05). Sixteen (88.9%) of the 18 patients in group B had a poor prognostic index (score 3 - 6) with a significantly higher percent difference (41.6%, p<0.05) than patients of group A. Within 10 days of admission, 3 patients (16.7%) died in group A and 6 (8.1%) in group B. However, no significant differences were observed in the Kaplan-Meier survival curves. No correlation with cardiovascular risk factors was observed.

CONCLUSIONS

Besides having an important diagnostic value, hyperattenuating middle cerebral artery sign is a reliable predictor of prognosis in terms of disability rather than mortality, as it reflect the larger extension of infarction.

[Digital cineradiography of the pharynx and the oesophagus after total or partial laryngectomy]

PURPOSE

The aim of the present study is to report our experience using digital cineradiography to assess morphological and functional disorders of the pharynx in patients with prior partial or total laryngectomy.

MATERIALS AND METHODS

From March 2000 to October 2002, 21 patients (18 males and 3 females) with prior total laryngectomy (12 patients), total laryngopharyngectomy (2 patients) and partial laryngectomy (7 patients) were examined. A digital cineradiography with 12 frames/second acquisition was performed in all patients. In four patients the procedure was interrupted for massive barium aspiration, without cough (silent aspiration). In 17 patients standing in the left posterior oblique position and prone in the right posterior oblique position the oesophagus and oesophagogastric junction were also examined. The water siphon test was performed at the end of the procedure. Small boluses (10 ml) of liquid (60% w/v) and high-density (250% w/v) barium, barium paste (110% w/v), and solid meal (obtained spreading a dry biscuit with barium paste) were used.

RESULTS

All patients with prior total laryngectomy and total laryngopharyngectomy showed morphological and functional disorders of the neopharynx: parapharyngeal diverticulum (2 cases), submandibular pouch (6 cases), fistulas (2 cases), lumen narrowing and post-surgical stenoses (2 cases), tumour recurrence (1 case), prominent cricopharynx (5 cases) and rhinopharyngeal reflux (4 cases). All patients with prior partial laryngectomy (7 cases) presented silent aspiration. Eleven patients had an oesophageal motility disorder, which was very serious in three of them with decrease in oesophageal clearing and barium retention in the oesophagus. Oesophagogastric junction evaluation showed hiatus hernia in six cases, two of them with associated gastro-oesophageal reflux.

CONCLUSIONS

Digital cineradiography appears able to identify the organic and functional postoperative complications of patient treated with partial or total laryngectomy. A special swallowing study can suggest to the speech therapist the best compensatory mechanism for improving patient swallowing and therefore quality of life.

Pitfalls and limitations of Magnetic Resonance Imaging in bucket-handle tears of knee menisci

PURPOSE

The aim of the present study was to assess the accuracy of magnetic resonance imaging (MRI) in the diagnosis of bucket-handle tears of the knee menisci, determining the sensitivity and specificity of the imaging for each of the signs typical of these tears.

MATERIALS AND METHODS

MR examinations of 495 patients suffering from knee traumas were assessed retrospectively. Forty-eight patients had arthroscopically-proven bucket-handle tears of the meniscus. MR examinations were performed using a 0.5-T superconducting magnet, with T1-weighted spin-echo (SE) and gradient-echo (GE) T2*-weighted sequences. Imaging findings used for the diagnosis were: a) double posterior cruciate ligament sign; b) flipped meniscus sign; c) presence of a displaced fragment of the meniscus in the intercondylar notch, visible in coronal and axial images; d) truncated triangular shape of the peripheral non-displaced portion of the meniscus, visible in coronal images.

RESULTS

A total of 43 out of 48 bucket-handle tears of the meniscus were correctly diagnosed at MR, thus overall MR accuracy was 98%. In 12 (28%) cases three signs were present simultaneously the double posterior cruciate ligament (sensitivity 28%, specificity 99%, accuracy 93%) + the displaced fragment in the intercondylar notch (sensitivity 69.8%, specificity 98.7%, accuracy 96.2%) + the truncated triangular shape of the peripheral portion of the meniscus (sensitivity 74.4%, specificity 98%, accuracy 96%). In 18 (42%) cases two signs were present together the displaced fragment of the meniscus + the truncated triangular shape of the peripheral portion of the meniscus. In 13 (30%) cases only one sign was presenting two cases the truncated triangular shape of the peripheral portion of the meniscus and in 11 cases the flipped meniscus sign (sensitivity 25.6%, specificity 93.4%, accuracy 87.5%). No statistically significant differences were found comparing the results for tears of the medial meniscus with those for the lateral meniscus.

CONCLUSIONS

MR imaging is highly accurate in diagnosing bucket-handle tears of the menisci due to its ability to identify a displaced fragment of the meniscus in the intercondylar notch or flipped over the anterior horn of the meniscus of origin. We speculate that bucket-handle tears not found by MR imaging are cases where the meniscus was displaced after MR examination.

[Thrombolytic therapy in myocardial infarction. Computerized tomography of encephalic complications]

PURPOSE

To evaluate the CT findings of intracerebral hemorrhage in patients undergoing thrombolytic therapy for acute myocardial infarction and to correlate the type of intracerebral hemorrhage with clinical outcome.

MATERIAL AND METHODS

We retrospectively reviewed the clinical records and CT scans of intracerebral hemorrhage on a total of 302 patients who underwent thrombolytic therapy for acute myocardial infarction at our institution from January 1996 to September 1999. In each patient we evaluated: the number, sites and size of hemorrhage, and the presence and severity of mass effect. The site of the hemorrhage was classified as intraparenchymal, intraventricular, subdural and subarachnoid.

RESULTS

Six patients (2%, mean age 74, range 66-80) developed intracerebral hemorrhage. There was a total of 22 hemorrhages: 1 subdural hemorrhage, 6 subarachnoid, 11 intraparenchymal and 4 intraventricular. Excluding intraventricular hemorrhage, 14/18 hemorr-hages were located supratentorially. In five patients there was a fluid-blood level. Three patients had severe mass effect with midline shift. Symptoms presented within 24 hours from the administration of thrombolytic therapy in all patients. All the patients who died had a large hematoma with a severe mass effect and a severe midline shift at CT scan. In the remaining patients, the hematoma was of medium size and no mass effect was seen.

CONCLUSIONS

The most common site of hemorrhage was supratentorial and intraparenchymal. Large volume intracerebral hemorrhage, multiple hemorrhages and mass effect with midline shift were associated with increased mortality. The most commonly observed finding was a fluid-blood level hematoma.

Retroaortic left renal vein joining the left common iliac vein

Retroaortic left renal vein joining the left common iliac vein is a rare congenital anomaly in the development of the inferior vena cava. To our knowledge, only one case has been reported in the literature; however, its imaging features have never been described. A 27-year-old male presented with a 1-year history of recurrent right flank pain, dysuria, hematuria, and fever (39 degrees C). Computed tomography and MR venography showed a retroaortic left renal vein joining the left common iliac vein. We present the CT and MR venography findings and discuss their feasibility in showing this congenital anomaly.

Transfusional hemochromatosis: quantitative relation of MR imaging pituitary signal intensity reduction to hypogonadotropic hypogonadism

PURPOSE

To assess the relationship between magnetic resonance (MR) imaging pituitary signal intensity reduction in patients with transfusional hemochromatosis and the clinical manifestation of hypogonadotropic hypogonadism.

MATERIALS AND METHODS

Pituitary MR imaging at 0.5 T was performed in 38 consecutive patients affected by secondary hemochromatosis and in 20 healthy volunteers. Serum ferritin levels were estimated in the affected population. Twenty (53%) of the 38 patients had hypogonadotropic hypogonadism diagnosed. Pituitary-to-fat signal intensity ratios were calculated from coronal gradient-echo (GRE) T2*-weighted MR images. The relationship between the quantitative reduction of the pituitary-to-fat signal intensity ratio and the clinical manifestation of pituitary dysfunction was assessed in the affected population. Signal intensity reduction in the anterior lobe of the pituitary gland was also correlated with the serum ferritin level.

RESULTS

The degree of reduction of the pituitary-to-fat signal intensity ratio correlated with the presence of hypogonadotropic hypogonadism, with a sensitivity of 90%, a specificity of 89%, and an overall accuracy of 89%. In addition, the reduction of pituitary signal intensity was greater in patients with higher ferritin levels (r = -0.55, r(2) = -0.30, P <.001).

CONCLUSION

The degree of signal intensity reduction, measured as the pituitary-to-fat signal intensity ratio for GRE T2*-weighted images, in patients with secondary hemochromatosis correlates with the severity of pituitary dysfunction.

Brain damage in hanging: a new CT finding

We report a 23-year-old man who attempted suicide by hanging. There have been few reports of involvement of the brain parenchyma shown on CT, all showing ischaemic lesions. This is the first report of multifocal intracerebral haematomas due to hanging seen on CT.

Reversible MRI abnormalities in an unusual paediatric presentation of Wernicke's encephalopathy

BACKGROUND

We report an unusual paediatric presentation of acute Wernicke's encephalopathy in a 12-year-old boy affected by chronic gastrointestinal disease. MRI demonstrated, in addition to the typical diencephalic and mesencephalic signal abnormalities on T2-weighted images, enhancement of the mammillary bodies and the floor of the hypothalamus.

MATERIALS AND METHODS

Following parenteral administration of thiamine for 4 days, the patient recovered from his neurological deficits and on follow-up enhanced MRI 1 month later, no signal abnormalities were found nor was there diencephalic or mesencephalic atrophy, as is usual in the chronic phase of the disease.

RESULTS

MRI provides crucial information in the diagnosis of Wernicke's encephalopathy, either in the acute or chronic phases of the disease.

CONCLUSION

Our report provides an additional clue for recognition of the acute phase of the disease; enhancement of the floor of the hypothalamus has not previously been described despite its recorded involvement at autopsy.

MR imaging of pancreatic changes in patients with transfusion-dependent beta-thalassemia major

OBJECTIVE

The aim of this study was to evaluate MR imaging changes of the pancreas in patients with transfusion-dependent beta-thalassemia major.

SUBJECTS AND METHODS

Twenty patients with transfusion-dependent beta-thalassemia major were examined using MR imaging at 0.5 T, with spin-echo T1-weighted, fast spin-echo T2-weighted, and gradient-echo T2*-weighted sequences. Image analysis was performed to assess pancreas-to-fat signal intensity ratios for all pulse sequences. Pancreatic exocrine and endocrine function and serum ferritin levels were assessed. Twenty healthy volunteers underwent MR imaging with the same three sequences and served as a control group.

RESULTS

The pancreas-to-fat signal intensity ratio was significantly decreased in 17 (85%) of the 20 patients on spin-echo T1-weighted images (p < .05), fast spin-echo T2-weighted images (p < .01), and gradient-echo T2*-weighted images (p < .01) when compared with the 20 volunteers in the control group. The pancreas-to-fat signal intensity ratio was significantly increased in three (15%) of the 20 patients on spin-echo T1-weighted images (p < .01) and fast spin-echo T2-weighted images (p < .05). In addition, in the 20 patients, we found a significant correlation between increased pancreas-to-fat signal intensity ratios and decreased serum trypsin levels (r = -.77, p < .01 for spin-echo T1-weighted sequences; r = -.75, p < .05 for fast spin-echo T2-weighted sequences; and r = -.74, p < .05 for gradient-echo T2*-weighted sequences). Likewise, for the 20 patients, we found a significant correlation between decreased pancreas-to-fat signal intensity ratios and increased serum ferritin levels for gradient-echo T2*-weighted images (r = -.65, p < .01). No correlation was found for the other clinical parameters evaluated.

CONCLUSION

MR imaging revealed signal intensity changes in the pancreas of patients with transfusion-dependent beta-thalassemia major. Patients with a major impairment of the exocrine pancreatic function had higher signal intensity of the pancreas because of fatty replacement of the parenchyma.