Comparing different analysis methods for quantifying the MRI amide proton transfer (APT) effect in hyperacute stroke patients.

Amide proton transfer (APT) imaging is a pH mapping method based on the chemical exchange saturation transfer phenomenon that has potential for penumbra identification following stroke. The majority of the literature thus far has focused on generating pH-weighted contrast using magnetization transfer ratio asymmetry analysis instead of quantitative pH mapping. In this study, the widely used asymmetry analysis and a model-based analysis were both assessed on APT data collected from healthy subjects (n = 2) and hyperacute stroke patients (n = 6, median imaging time after onset = 2 hours 59 minutes). It was found that the model-based approach was able to quantify the APT effect with the lowest variation in grey and white matter (≤ 13.8 %) and the smallest average contrast between these two tissue types (3.48 %) in the healthy volunteers. The model-based approach also performed quantitatively better than the other measures in the hyperacute stroke patient APT data, where the quantified APT effect in the infarct core was consistently lower than in the contralateral normal appearing tissue for all the patients recruited, with the group average of the quantified APT effect being 1.5 ± 0.3 % (infarct core) and 1.9 ± 0.4 % (contralateral). Based on the fitted parameters from the model-based analysis and a previously published pH and amide proton exchange rate relationship, quantitative pH maps for hyperacute stroke patients were generated, for the first time, using APT imaging.

Imaging biomarkers in acute ischemic stroke trials: a systematic review.

BACKGROUND AND PURPOSE: Imaging biomarkers are increasingly used to provide a better understanding of the pathophysiology of acute ischemic stroke. However, this approach of routinely using imaging biomarkers to inform treatment decisions has yet to be translated into successful randomized trials. The aim of this study was to systematically review the use of imaging biomarkers in randomized controlled trials in patients with acute ischemic stroke, exploring the purposes for which the imaging biomarkers were used. MATERIALS AND METHODS: We performed a systematic review of imaging biomarkers used in randomized controlled trials of acute ischemic stroke, in which a therapeutic intervention was trialed within 48 hours of symptom onset. Data bases searched included MEDLINE, EMBASE, strokecenter.org, and the Virtual International Stroke Trials Archive (1995-2014). RESULTS: Eighty-four studies met the criteria, of which 49 used imaging to select patients; 31, for subgroup analysis; and 49, as an outcome measure. Imaging biomarkers were broadly used for 8 purposes. There was marked heterogeneity in the definitions and uses of imaging biomarkers and significant publication bias among post hoc analyses. CONCLUSIONS: Imaging biomarkers offer the opportunity to refine the trial cohort by minimizing participant variation, to decrease sample size, and to personalize treatment approaches for those who stand to benefit most. However, within imaging modalities, there has been little consistency between stroke trials. Greater effort to prospectively use consistent imaging biomarkers should help improve the development of novel treatment strategies in acute stroke and improve comparison between studies.

Fatal herpesvirus 6 encephalitis after unrelated bone marrow transplant.

A complex pattern of neurological dysfunctions with generalized seizures and visual allucinations, but without focal signs, suddenly arose 20 days after an unrelated bone marrow transplant for chronic myelogenous leukemia (CML) in a 13-year-old girl, accompanied by signs of acute skin graft-versus-host disease (GVHD). Magnetic resonance imaging (MRI) revealed multiple bilateral foci of signal abnormalities, which were exclusively localized in the grey matter, sparing the white. Extensive microbiological and virological assays of cerebrospinal fluid (CSF) allowed the identification of HHV-6, variant A, DNA. Further progression of both neurological alterations and of skin and gut GVHD led to a fatal outcome 2 weeks later. A retrospective analysis of both the recipient and donor mononuclear cell suspensions supported the hypothesis that HHV-6 had been acquired from the donor with the bone marrow graft. This report suggests a pathogenetic role of HHV-6 in viral encephalitis in immunocompromised bone marrow transplant (BMT) recipients, and its possible association with GVHD.

Contractile response of the human isolated urinary bladder to neurokinins: involvement of NK-2 receptors.

The contractile response to substance P (SP), neurokinin A (NKA) and arginin-neurokinin B (Arg-NKB) (a water soluble analogue of NKB) was investigated in detrusor muscle strips from the dome of the urinary bladder obtained from patients undergoing total cystectomy for carcinoma of the bladder base. Spontaneous activity and response to nerve stimulation indicated that the material used in this study has characteristics similar to those described for 'normal' human detrusor muscle. All neurokinins induced a concentration-related contraction with sensitivity at nM concentrations and the following rank order of potency: NKA (90) greater than Arg-NKB (22) greater than SP (1). These findings indicate the involvement of NK-2 receptors in the contractile response of human detrusor muscle to neurokinins.

MR imaging of the cauda equina in hereditary motor sensory neuropathies: correlations with sural nerve biopsy.

BACKGROUND AND PURPOSE: Although spinal root abnormalities are known to occur, spinal MR examination is seldom performed in hereditary motor and sensory neuropathies (HMSN). The following work was undertaken to assess the MR imaging spectrum of lumbosacral spinal nerve root abnormalities and determine whether intradural nerve root involvement could be related to any biopsy feature. METHODS: Ten consecutive patients (eight male, two female; age range, 28-65 yrs) with Charcot-Marie-Tooth (CMT) (type I = 5, type II = 2) and Déjèrine-Sottas disease (DSD) (n = 3) underwent a contrast-enhanced lumbosacral MR examination. Sural nerve biopsy was performed in all patients. Atypical clinical features were present in two patients. The MR scans of each patient were reviewed for possible causes of myeloradiculopathy, spinal nerve root and ganglia dimensions, signal change, and abnormal enhancement. RESULTS: In the seven patients with CMT, abnormal MR findings were intradural nerve root hypertrophy (n = 2), signal abnormalities (n = 2), and enhancement (n = 3). Two of three patients with DSD had the abnormal MR finding of intradural nerve root enhancement. In both patients with atypical clinical features, MR imaging showed nerve root hypertrophy and enhancement. Both findings were related to an increased number of onion bulbs at sural nerve biopsy. Inflammatory infiltrates were not observed in any patients. CONCLUSION: In patients with HMSN enhancement of intradural spinal nerve roots, whether or not associated with marked thickening, may be found on lumbosacral MR examinations. Spinal nerve root thickening may be responsible for atypical symptoms, and its visibility on MR images represents a useful adjunct to diagnosis. Lumbosacral spinal nerve root abnormalities were related to an extremely high number of onion bulbs (indicating active demyelination) at sural nerve biopsy. Nerve root enhancement does not seem to be related to inflammatory infiltrates.

Epidermal nevus syndrome: MR of intracranial involvement.

Focal thickening of the calvarium, hypoplasia of the white matter, cortical calcifications, and a leptomeningeal drape that enhanced after contrast injection were demonstrated by MR in the parietooccipital region ipsilateral to a facial sebaceous nevus in a patient with epidermal nevus syndrome.

Decision-making in the scheduling of endovascular treatment after brain arteriovenous malformation haemorrhage: a retrospective single centre study.

The appropriate timing for endovascular intervention after brain arteriovenous malformation (bAVM) rupture is not known. This paper aims to determine factors that lead to early endovascular intervention and to investigate whether early intervention has the same complication rate as late intervention in a single centre. All patients who underwent endovascular treatment for a ruptured bAVM at our institution in the period January 2007 and July 2010 were included in this retrospective observational study. Of 50 patients, 33 had early endovascular intervention, defined as within 30 days of haemorrhage and the remaining 17 patients had endovascular treatment at day 30 or beyond. A greater proportion of patients treated within the first 30 days were in neuro-intensive care preoperatively (51.5% vs. 23.5%, p=0.07). A 'high-risk' angioarchitectural feature was identified in more patients who had acute intervention (78.8% vs. 11.8%, p<0.0001) and targeted embolization was also more frequent in this group (48.5% vs. 5.9%, p=0.004). Nidal aneurysms, venous varices and impaired venous outflow (venous stenosis) were the principal 'high risk' features. Clinically apparent complications occurred in 10.8% of procedures with permanent neurological deficit in 3.6%. There was no directly procedure-related mortality. There was no statistically significant difference in the complication rate of early procedures compared with delayed interventions (12.5% vs. 7.4%, p=0.71). Greater initial injury severity and the presence of high-risk lesion characteristics are the factors that lead to early endovascular intervention. Early intervention is associated with a higher complication rate, but this difference is not statistically significant.

Endovascular Coiling of Aneurysm Remnants after Clipping in Patients with Follow-up. A Single Center Experience.

SUMMARY: The vast majority of intracranial aneurysms can be obliterated completely with surgical clipping. However, postoperative remnants occur in about 4 to 8% of patients who undergo postoperative angiography. Endovascular embolization has been successfully performed in patients with postoperative aneurysm remnant and it may represent a therapeutic alternative to surgical reintervention. Twelve aneurysm remnants after surgical clipping were treated with endovascular embolization using GDC. All aneurysms were located in the anterior circulation. Our experience confirms the feasibility and relative safety of this treatment strategy that may be considered a valid alternative to reintervention.

[Partial lesions of the posterior cruciate ligament of the knee: CT findings]. / Lesioni parziali del legamento crociato posteriore del ginocchio: reperti TC.

Posterior cruciate ligament (PCL) tears are more common than usually reported, especially in athletes. In the acute phase, PCL tears are particularly difficult to diagnose at clinical examination and may go unnoticed even to a skilled clinician because of concomitant lesions to other structures, of hematrhos or of strong muscular defense. The PCL is responsible for 95% of biomechanical knee stability and therefore plays a major role in the maintenance of joint congruence. In the long run, PCL tears cause posterolateral instability and an untimely development of degenerative changes, particularly at the patella. Site and grade of PCL tears must therefore be accurately assessed to plan the most appropriate treatment and to avoid the abuse of arthroscopy, toward improving cost-effectiveness for public health structures. Nowadays, CT of the knee joint is performed more frequently than MRI because the former is more easily available, in agreement with the current Italian economic choices in the field of public health. CT allows the accurate identification of complete and partial PCL tears. In our series (765 patients), PCL tears were more common than reported in the literature (9.5% vs 5%); moreover, PCL tears were always associated with lesions in other structures--e.g., anterior cruciate ligament, menisci. In conclusion, the CT demonstration of the knee joint, together with the knowledge of the physiopathologic relationships among different structures, allows better understanding of painful syndromes of the anterior joint compartment, which are particularly common in athletes. These syndromes are usually caused by a femoro-patellar overload in people suffering from congenital ligament laxity, which may or may not be associated with abnormal knee morphotype--i.e., valgus, recurvatus.

Cerebral magnetic resonance imaging in a patient with ankylosing spondylitis and multiple sclerosis-like syndrome.

Clinical and cerebral magnetic resonance imaging (MRI) findings in a patient with ankylosing spondylitis (AS) and multiple sclerosis-like (MS-like) syndrome are reported. Cerebral MRI demonstrated multiple, MS-like, scattered foci of signal abnormality, one of which showed contrast enhancement. Lesion dissemination in "space and time" is a hallmark for diagnosis of MS, and its demonstration by enhanced cerebral MRI prompted suspicion of coexistence of MS and AS in our patient.

MRI of cerebral rheumatoid pachymeningitis: report of two cases with follow-up.

We report the clinical and neuroradiological features of cerebral rheumatoid pachymeningitis with 1 year follow-up in two patients. MRI of the head enabled noninvasive diagnosis of both the meningeal abnormality and its complications, consisting of hypertensive hydrocephalus and superior sagittal sinus thrombosis, respectively. Dural sinus thrombosis, very uncommon in rheumatoid arthritis, was confirmed by phase-contrast MRA. Worsening of the pachymeningitis at follow-up was observed in both patients despite regression or stability of the clinical picture and long-term therapy.

[Diagnostic imaging of idiopathic synovial osteochondromatosis]. / Diagnostica per immagini della osteocondromatosi sinoviale idiopatica.

To study the characteristic diagnostic imaging features of idiopathic synovial osteochondromatosis with different imaging techniques as well as the differential diagnosis between idiopathic and secondary forms, 7 patients with idiopathic synovial osteochondromatosis were retrospectively examined from January, 1988, through December, 1993. In 6 patients the disease was monoarticular (the shoulder in 4 patients, the elbow in one patient and the hip in another one). In one patient two joints were involved--i.e., the left elbow and the right knee. In all cases the clinical picture was characterized by pain and functional impairment of the involved joint, which was swollen in 3 patients. The definitive diagnosis was made on the basis of surgical and/or arthroscopic findings in 4 cases and of radiologic and MR findings in 4 cases and of radiologic and MR findings in 4 cases. In all patients conventional radiology showed multiple juxtaarticular calcified and/or ossified bodies, mostly uniform in size. Calcification patterns varied from small specks of calcification (2-3 mm) to large calcified bodies (1-2 cm) with a typical "cluster" appearance. Conventional arthrography and computerized arthrotomography (performed on 3 patients) demonstrated the intraarticular site of calcified bodies as filling defects at hypertrophic synovial recesses. CT and MRI (performed on 4 patients) allowed easier demonstration of calcified/ossified bodies and of their relationships with articular structures. Moreover, synovial proliferation and cartilagineous nodules obliterating articular spaces, synovial recesses and juxtaarticular bursae were depicted. In particular, MRI allowed the differentiation not only of the different stages of the disease, but also of the idiopathic from the secondary forms. MRI plays therefore a fundamental role in the diagnosis of idiopathic synovial osteochondromatosis, directly influencing surgical planning, i.e., removing articular loose bodies with partial or total synoviectomy by means of arthroscopy.

Disappearance of cerebral arteriovenous malformations after partial endovascular embolisation: four cases with follow-up.

We report four patients with late angiographic follow-up of spontaneous occlusion of residual cerebral arteriovenous malformation after partial embolisation. Discussion is focused on the possible mechanisms leading to obliteration according to the latest concepts on angioarchitectural remodelling, malformation development and evolution with a brief review of the literature.

Disappearance of a cerebral arteriovenous malformation after partial endovascular embolisation.

SUMMARY: The authors report the observation of a patient with a Spetzler-Martin grade 3, symptomatic, sulcal cerebral arteriovenous malformation (cAVM) of the left precuneus that after partial, uncomplicated, endovascular embolisation disappeared at 4, 6 and 12 months follow-up. Discussion focuses on the angioarchitectural remodelling of the cAVM over time according to the latest concepts on AVM development and evolution.

MRI of congenital Foix-Chavany-Marie syndrome.

MRI findings of bilateral central macrogyria allowed the diagnosis of a congenital variant of Foix-Chavany-Marie syndrome in four patients aged between 13 and 32 years, with facio-pharyngo-glosso-masticatory central diplegia, mental retardation and seizures.

Magnetic resonance imaging of cerebral associative white matter bundles employing fast-scan techniques.

Rapid scan techniques have introduced new sequence parameters as well as novel contrast concepts into everyday magnetic resonance imaging (MRI). In particular contrast characteristics of fast-spin echo (FSE) sequences showed some significant differences when compared to conventional spin echo images. The purpose of this work was to demonstrate the capabilities of FSE MRI in identifying and characterizing the in vivo anatomy of the main cerebral associative systems. Between March and November 1995, 20 healthy adult volunteers (12 males, 8 females, mean age 35 years) were submitted to a cranial MRI examination (1.5 Philips Gyroscan NT). In all cases axial and coronal 2-dimensional FSE T2-weighted and 2-dimensional inversion recovery FSE T1-weighted images were obtained. All MRI images were examined by a neuroradiologist (G. Dal Pozzo) for the depiction of the following compact white matter fiber bundles: anterior commissure, corpus callosum, superior fronto-occipital fasciculus, cingulum, fornix, mammillothalamic tract, uncinate fasciculus, superior and inferior longitudinal fasciculus. All these associative pathways could be well identified on T2-weighted images due to a lower signal intensity with respect to the surrounding white matter. On T1-weighted images only the corpus callosum, the anterior commissure and the fornix could always be identified. Correlation with myelin-specific colorations (Luxol fast blue stains) in anatomic atlases and a review of the literature on the myelinization process during infancy indicate that the short T2 relaxation times of the aforementioned cerebral associative systems may be due to heavy myelination and high fiber density. The correct visualization of interintrahemispheric associative white matter fiber bundles may play an important role in white matter disorders like dys- and demyelinating diseases and in the spreading of vasogenic edema and/or tumor being useful for their staging.