T1 Isointense Research Articles

Evaluation of Radiological Indicators of Surgical Plane of Meningiomas

The study was to objectively assess radiological indicators in conventional MR sequences with respect to operative findings and tumor interface during surgical resection of meningiomas. Signal intensity of meningioma on T1, T2, FLAIR, and contrast MR sequences were prospectively noted and analyzed in relation to intraoperative tumor consistency, vascularity, dissection plane, Simpson’s grade of excision, and histopathology. Appropriate univariate and multivariate analysis were performed. Of the total 70 patients (44 females, 26 males), 18 had skull base, 15 had convexity, 10 had parasagittal, 11 had falcine, and 7 had tentorial meningiomas. Majority (67) had tumors which were hypo to isointense in T1. While 14 had hypointense signal in T2, only 8 were hypointense in FLAIR. 21 had inhomogeneous enhancement. 28 had marked tumor interface in MRI, while 33 and 9 had regular and irregular border, respectively. 19 had no edema, while 33 and 18 had focal and lobar edema respectively. Inhomogeneous enhancement (p = 0.01) and FLAIR hypointensity (p = 0.03) had significant association with tumor hardness. FLAIR hypointensity (p = 0.01) had significant association with low vascularity. Skull base location (p = 0.04), FLAIR hypointensity (p = 0.02), irregular border (p = 0.01), and recurrence (p = 0.01) had significant association with subpial or mixed plane of cleavage. Only skull base location (p = 0.01) had significant impact on extent of excision. T2 hypointensity (p = 0.001) and FLAIR hypointensity (p = 0.01) had significant association with Fibroblastic or Psammomatous meningioma. In multivariate analysis, FLAIR hypointensity (p = 0.02) and skull base location (p = 0.04) had significant independent association with suboptimal surgical plane, while skull base location (p = 0.01) had significant association with extent of excision. Among MRI sequences, FLAIR hypointensity had the best performance characteristic with specificity of 94% to predict suboptimal surgical plane. In conclusion, FLAIR images correlate with suboptimal surgical plane during resection of meningioma with high specificity.

Epitrochlear cat scratch disease: unique imaging features allowing differentiation from other soft tissue masses of the medial arm.

Evaluate anatomic and imaging features of epitrochlear regional adenopathy secondary to cat scratch disease (CSD) to assist differentiation of CSD from other soft tissue masses at the elbow. Retrospective review of 24 confirmed cases of CSD. Patient demographics, clinical presentation and radiographic (R; n = 10), CT (n = 3), ultrasound (US; n = 5), and MR (n = 21) images were reviewed. Lesion location, size, number of masses, and intrinsic characteristics on R/CT/US/MR and presence of soft tissue inflammatory changes or adjacent bone or joint involvement were established through the consensus interpretation by four musculoskeletal radiologists. The average patient age was 18.6years. Mass location was anterior and superficial to the medial intermuscular septum (100%) with the masses posterior or posteromedial to the basilic vein (92%). Three or fewer lymph nodes were involved in 92%. Masses were noncalcified with adjacent inflammatory change (R = 90%, CT = 100%). US showed hypoechoic soft tissue echogenicity masses with defined to minimally irregular margins (80%) and preserved central hilar hypervascularity on Doppler (100% of cases). On MR, masses were T1 isointense (62%), T2 isointense (54%), intermediate signal on T2 images with fat suppression (55%), and had perilesional inflammatory changes (95%), perilesional fluid collections (38%), adjacent muscle edema (81%), hyperintense cental hilar vascular enhancement (65%) and occasional preserved central hilar fat (14%). Cat scratch disease is suggested by the characteristic location of a medial epitrochlear mass superficial to the brachial fascia and posterior to the basilic vein with surrounding inflammatory changes and preservation of hilar vascular architecture, hilar enhancement and occasional hilar fat.

An unusual thoracic spinal pathology presenting as a dorsally exophytic intramedullary lesion

A 45-year-old woman presented with progressive spastic weakness of her lower limbs of 5 years' duration. She had previously undergone laminectomy and decompression of a thoracic lesion elsewhere. Magnetic resonance imaging of her spine (Fig. 1) demonstrated a well-defined intramedullary lesion from the T3 to T6 levels that was hyperintense on T1- and T2-weighted sequences. It had a broad, dorsally located exophytic component. Patchy areas of heterogeneously enhancing T2 isointense soft tissue components were seen in the superior aspect of the lesion (Fig. 2). There was no infiltration of the lesion into surrounding structures. The diagnosis was consistent with that of a recurrent intramedullary lipoma with a dorsally exophytic component. She underwent re-exploratory surgery and decompression of the lesion. Histopathology confirmed the lesion to be a lipoma. Fig. 2Gadolinium-enhanced T1 magnetic resonance imaging (MRI): (Left) midsagittal section showing patchy enhancement in the superior aspect of the lesion; (Right) axial section demonstrating the enhancing area extending into the exophytic component. View Large Image Figure Viewer Download Hi-res image

Qualitative Assessment of Diffusion Weighted Imaging and Susceptibility Weighted Imaging of Myeloid Sarcoma Involving the Brain.

Myeloid sarcoma is a rare form of extramedullary leukemia, which can present with or without systemic leukemia. The purpose of this study was to evaluate characteristic computed tomography (CT) and magnetic resonance imaging (MRI) findings (including diffusion weighted imaging and susceptibility weighted imaging) of myeloid sarcoma involving the brain. One hundred nine patients with pathologically proven myeloid sarcoma underwent pretreatment CT and MRI, which were retrospectively reviewed. Computed tomography and MRI characteristics reviewed include lesion location, shape, size, architecture, margins, ± multiplicity, ± bone destruction, pattern and degree of enhancement, ± restricted diffusion, and ± susceptibility artifact. Twenty-five patients (14 men, 11 women; mean age, 55 years; range, 9-80 years) met the inclusion criteria. Acute myeloid leukemia with subtypes M3 (44.4%) and M5 (22.2%) were the most common. On unenhanced CT, mean lesion size was 1.9 ± 0.4 cm; 60% were intra-axial hyperdense masses, 8% were intraventricular hyperdense masses, 12% were isodense intra-axial masses, and 20% of cases were extra-axial hyperdense nodular masses. There was no observable intralesional or perilesional calcium. On MRI, mean lesion size was 2.1 ± 0.6 cm. The lesions were isointense (80%) or hypointense (20%) on T1-weighted images with homogeneous (88%) or heterogeneous (12%) enhancement. On fluid-attenuated inversion recovery and T2-weighted images, lesions were hyperintense (96%) or isointense (4%) with mild vasogenic edema. Majority (96%) of cases demonstrated restricted diffusion, whereas only a few (16%) demonstrated susceptibility artifact. In patients with history of leukemia or myeloproliferative disorder, identification of homogenous mass hyperdense on unenhanced CT, T1 isointense, and T2/fluid-attenuated inversion recovery hyperintense with restricted diffusion and homogenous postcontrast enhancement without significant susceptibility artifact is suggestive of myeloid sarcoma.

Primary Extremity Liposarcoma: MRI Features, Histopathology, and Clinical Outcomes.

This study aimed to describe magnetic resonance imaging (MRI) features of extremity liposarcoma (LPS) subtypes, correlating with histopathology and clinical outcomes. In this retrospective study, we included 125 patients (80 men, 45 women; mean age, 53 years) with extremity LPS [23 atypical lipomatous tumor (ALT), 9 dedifferentiated (DDLPS), 70 myxoid (MLPS), 23 pleomorphic (PLPS)]. Pretreatment MRI of primary tumors in 56 patients (10 ALT, 4 DDLPS, 28 MLPS, 14 PLPS) was reviewed. All subtypes were predominantly T1 isointense relative to skeletal muscle (DDLPS = 3/4, MLPS = 28/28, PLPS = 13/14) and T2 hyperintense (ALT = 10/10, DDLPS = 3/4, MLPS = 28/28, PLPS = 14/14) except for ALT which were T1 hyperintense (8/10). Within MLPS, high grade was associated with unencapsulated margins (P = 0.05) and solid, nodular enhancement (P < 0.0001). Peritumoral edema (P = 0.03) and T2 heterogeneity (P = 0.05) predicted pulmonary (rather than extrapulmonary) metastases in MLPS. Tumor subtype correlated with mortality (P = 0.04). The MRI features can help to distinguish between extremity LPS subtypes, and can predict histopathologic grade and metastatic pattern in myxoid LPS.

Diffuse Large B-Cell Lymphoma Mimicking Schwannoma of Lumbar Spine.

A rare case of solitary diffuse large B-cell lymphoma arising from the lumbar spinal nerve root is reported. A 37-year-old man presented with a 3-month history of progressive numbness and paraparesis in both legs. The initial diagnosis was benign primary intradural extramedullary tumor including schwannoma and meningioma. Histopathological examination revealed diffuse large B-cell lymphoma. While a well-defined T1 isointense mass is common in primary spinal schwannoma, the present case was atypical and had a yellowish neural component. The pathogenesis and radiological findings of spinal diffuse large B-cell lymphoma are discussed and related literature is reviewed.

Challenges of Preoperative Diagnosis and Management of Scalene Intramuscular Angioma

Intramuscular angioma of scalene muscle is rare with only five cases reported so far. Four of them have not been suspected before surgery; one was diagnosed preoperatively by core biopsy. Preoperative diagnosis is important for management. Awareness of cytologic features could help preoperative diagnosis when need of ruling out malignancy and coagulopathy make fine needle aspiration a choice. We herein demonstrate a new case of a 27 year old male with history of hepatocellular carcinoma, who presented with a 6 cm left supraclavicular mass. The fine needle aspiration was paucicellular; however, the bland ovoid to spindle cells with a whirling and luminal arrangement in the background of blood, fatty drops and degenerate muscle are suggestive of intramuscular angioma. The magnetic resonance imagines (MRI) demonstrate a T1 isointense and T2 hyperintense ill-defined lesion splaying anterior and mid scalene muscles with subtle vascular voids at periphery. These features in combination with cytology findings indicate intramuscular angioma. The pre-operative findings are correlated to the histologic picture of mixed capillaries and varying sized venues intervening with fatty tissue and atrophic muscle. Intraoperatively, the mass is adjacent to the brachial plexus rootlets, interdigitating with the scalene muscle and pushing the carotid sheath, left subclavicular artery and vein aside. Following embolization, the mass is resected with minimal bleeding. Our case suggests that scalene intramuscular angioma can be successfully managed by surgery after embolization; preoperative diagnosis rendered by cytologic features and imaging characters would aid the planning of surgery.

“Snake eyes” sign confined to thoracic spinal cord caused by infarction

A 59-year-old man presented with sudden weakness, paresthesia, and sensory loss in both lower limbs. Sagittal magnetic resonance images demonstrated T1 isointense, T2 hyperintense non-enhancing intramedullary lesion from T3 to T6 (Fig. 1). Axial T2-weighted image revealed symmetric hyperintensities in the grey matter of anterior horns, giving the “snake eyes” sign (Fig. 2). The clinical and imaging diagnosis was spinal cord infarction. Fig. 2Axial T2-weighted magnetic resonance image showed symmetric hyperintensities in the grey matter of anterior horns of the thoracic spinal cord caused by infarction, giving the “snake eyes” sign. View Large Image Figure Viewer Download Hi-res image

Pathological laughter as prodromal manifestation of transient ischemic attacks—case report and brief review

BackgroundBased on a case report, the authors reviewed the data about involuntary emotional expression disorder (IEED). IEED includes the syndromes of pathological laughing and crying (PLC) and emotional lability (EL). PLC is a rare disorder of emotional expression characterized by relatively uncontrollable episodes of laughter and crying or both that do not have an apparent motivating stimulus.Case presentationAuthors report the case of a 59-year-old man who presented with recurrent episodes of PLC of approximately 2 min duration, consisting of accelerated breathing, emission of guttural, snoring sounds, frowning of the eyebrows, followed by laughter accompanied by motor restlessness of all four limbs. PLC episodes preceded left carotid transient ischemic attacks (TIA’s) manifested by reversible aphasia and right hemiparesis. Electroencephalography performed during PLC episodes revealed no spike-wave activity. Brain magnetic resonance imaging showed lacunar infarcts in the left lenticulo-capsulo-thalamic area and multiple round lesions in the cortical-subcortical and in the deep white matter of frontal-parietal-occipital lobes bilaterally, with T2 hyperintensity, T1 isointensity and no diffusion changes. The episodes were interpreted as transient ischemic attacks although gelastic seizures could not be excluded. The etiological investigations revealed unstable plaques on the left carotid artery bulb and the aortic arch and a degenerative mitral valve stenosis. The patient was treated first with antiplatelet therapy and antiepileptic drugs but PLC stopped only after anticoagulation was started. During follow-up the patient continued to have left carotid and vertebrobasilar TIA’s being on oral anticoagulation. The patient became asymptomatic only after mitral valve replacement was performed.ConclusionsThis case illustrates the difficulty distinguishing between gelastic epilepsy and TIA’s in cases of PLC episodes and discuss the neuroanatomic bases and pathophysiology of this rare condition.Electronic supplementary materialThe online version of this article (doi:10.1186/s12883-015-0457-3) contains supplementary material, which is available to authorized users.

Heterogeneity of acute multiple sclerosis lesions on sodium (23Na) MRI

Background: Advanced magnetic resonance imaging (MRI) techniques provide a window into pathological processes in multiple sclerosis (MS). Nevertheless, to date only few studies have performed sodium MRI in MS. Objectives: We analysed total sodium concentration (TSC) in hyperacute, acute and chronic lesions in MS with 23Na MRI. Methods: 23Na MRI and 1H MRI were performed in 65 MS patients and 10 healthy controls (HC). Mean TSC was quantified in all MS lesions with a diameter of >5 mm and in the normal appearing white and grey matter (NAWM, NAGM). Results: TSC in the NAWM and the NAGM of MS patients was significantly higher compared to HC (WM: 37.51 ± 2.65 mM versus 35.17 ± 3.40 mM; GM: 43.64 ± 2.75 mM versus 40.09 ± 4.64 mM). Acute and chronic MS lesions showed elevated TSC levels of different extent (contrast-enhancing lesions (49.07 ± 6.99 mM), T1 hypointense lesions (45.06 ± 6.26 mM) and remaining T1 isointense lesions (39.88 ± 5.54 mM)). However, non-enhancing hyperacute lesions with a reduced apparent diffusion coefficient showed a TSC comparable to the NAWM (37.22 ± 4.62 mM). Conclusions: TSC is not only a sensitive marker of the severity of chronic tissue abnormalities in MS but is also highly sensitive to opening of the blood–brain barrier and vasogenic tissue oedema in contrast-enhancing lesions.

Multiple Segmental Hemangiomas Over One Half of the Body - A Rare Feature of PHACES Syndrome

To the Editor: PHACES syndrome (OMIM 606529) is an association of large, plaque-like, Bsegmental^ hemangiomasH of the face, with one or more of the following anomalies: Pposterior fossa brain malformations, A-arterial lesions, C-cardiac abnormalities/ coarctation of aorta, E-eye abnormalities and S-sternal defect. An 1y 3mo old girl presented to us with history of reddish raised skin lesions on the face, since age of 15d. Gradually, similar multiple lesions appeared on left half of the body. They increased in size upto 5mo of age and later ulcerated, followed by healing with scarring. On examination, her radial pulses were well felt; femoral and dorsalis pedis pulses were weak. Multiple large segmental hemangiomas were present over left half of the body (Fig. 1). Written informed consent was obtained from the patient for publication of this case report and any accompanying images. On MRI, these lesions showed T1 isointensity, T2 hyperintensity with areas of blooming within. CT angio showed complete interruption of aortic arch type B, descending thoracic aorta supplied by patent ductus arteriosus (PDA) and persistent left sided superior venacava arising from coronary sinus without bridging veins. MRA brain showed hypoplastic left vertebral artery. MRI brain, thyroid function tests, ultrasound abdomen and lumbosacral spine were normal; stool for occult blood was negative. Hemangiomas are the most common benign tumors of infancy and may be mistaken for other conditions depending on their stage of development. Nascent lesions may be confused with capillary malformations; naevus anaemicus or naevus depigmentosus. Superficial hemangiomas may resemble pyogenic granulomas, congenital hemangiomas, tufted angiomas or kaposiform hemangioendotheliomas. Deeper tumors may mimic venous or lymphatic malformations, dermoid cysts, infantile myofibromatosis, lipomas or soft tissue sarcomas. The correct diagnosis is based on typical features of hemangioma namelyonset after birth; followed by phases of proliferation, plateau and involution. On MRI they appear isointense (T1), hyperintense (T2), homogeneously enhancing soft tissue mass, with flow voids within and around. Histologically they stain positively for the glucose transporter protein,

Postoperative intraspinal subdural collections after pediatric posterior fossa tumor resection: incidence, imaging, and clinical features.

Postoperative intraspinal subdural collections in children after posterior fossa tumor resection may temporarily hinder metastasis detection by MR imaging or CSF analysis, potentially impacting therapy. We investigated the incidence, imaging and clinical features, predisposing factors, and time course of these collections after posterior fossa tumor resection. Retrospective review of postoperative spine MRI in 243 children (5.5 ± 4.6 years of age) from our clinical data base postresection of posterior fossa tumors from October 1994 to August 2010 yielded 37 (6.0 ± 4.8 years of age) subjects positive for postoperative intraspinal subdural collections. Their extent and signal properties were recorded for postoperative (37/37), preoperative (15/37), and follow-up spine (35/37) MRI. Risk factors were compared with age-matched internal controls (n = 37, 5.9 ± 4.5 years of age). Associations of histology, hydrocephalus and cerebellar tonsillar herniation, and postoperative intracranial subdural collections with postoperative intraspinal subdural collections were assessed by the Fisher exact test or χ(2) test. The association between preoperative tumor volume and postoperative intraspinal subdural collections was assessed by the Wilcoxon rank sum test. The overall incidence of postoperative intraspinal subdural collections was 37/243 (15.2%), greatest ≤7 days postoperatively (36%); 97% were seen 0-41 days postoperatively (12.9 ± 11.0 days). They were T2 hyperintense and isointense to CSF on T1WI, homogeneously enhanced, and resolved on follow-up MR imaging (35/35). None were symptomatic. They were associated with intracranial subdural collections (P = .0011) and preoperative tonsillar herniation (P = .0228). Postoperative intraspinal subdural collections are infrequent and clinically silent, resolve spontaneously, and have a distinctive appearance. Preoperative tonsillar herniation appears to be a predisposing factor. In this series, repeat MR imaging by 4 weeks documented improvement or resolution of these collections in 88%.

LINKS: Learning-based multi-source IntegratioN frameworK for Segmentation of infant brain images

Segmentation of infant brain MR images is challenging due to insufficient image quality, severe partial volume effect, and ongoing maturation and myelination processes. In the first year of life, the image contrast between white and gray matters of the infant brain undergoes dramatic changes. In particular, the image contrast is inverted around 6–8months of age, and the white and gray matter tissues are isointense in both T1- and T2-weighted MR images and thus exhibit the extremely low tissue contrast, which poses significant challenges for automated segmentation. Most previous studies used multi-atlas label fusion strategy, which has the limitation of equally treating the different available image modalities and is often computationally expensive. To cope with these limitations, in this paper, we propose a novel learning-based multi-source integration framework for segmentation of infant brain images. Specifically, we employ the random forest technique to effectively integrate features from multi-source images together for tissue segmentation. Here, the multi-source images include initially only the multi-modality (T1, T2 and FA) images and later also the iteratively estimated and refined tissue probability maps of gray matter, white matter, and cerebrospinal fluid. Experimental results on 119 infants show that the proposed method achieves better performance than other state-of-the-art automated segmentation methods. Further validation was performed on the MICCAI grand challenge and the proposed method was ranked top among all competing methods. Moreover, to alleviate the possible anatomical errors, our method can also be combined with an anatomically-constrained multi-atlas labeling approach for further improving the segmentation accuracy.

Pancreatic duct "Icicle sign" on MRI for distinguishing autoimmune pancreatitis from pancreatic ductal adenocarcinoma in the proximal pancreas.

To determine reliable MRI features of autoimmune pancreatitis (AIP) in the proximal pancreas that could allow its differentiation from pancreatic ductal adenocarcinoma (PDAC). Twenty-three patients with AIP and 61 patients with PDAC in the proximal pancreas underwent MRI. Two observers analyzed MRI for lesion morphology, hypointensity degree on T1-weighted images, enhancement pattern during dynamic phases, capsule-like rim, presence of cysts and duct penetrating sign, morphology of bile duct, and icicle appearance and tortuosity of the upstream pancreatic duct. Sensitivity and specificity for the diagnosis of AIP were calculated for each category or combined. When isointensity on the portal and late phase of MRI and/or the icicle sign of pancreatic duct are applied, 100 % sensitivity for the diagnosis of AIP in the proximal pancreas was achieved. Applying both mild T1 hypointensity similar to the spleen and the icicle sign enabled 100 % specificity for the diagnosis of AIP by differentiating it from PDAC. The combination of the icicle sign in the upstream pancreatic duct and mild T1 hypointensity or isointensity on portal and late phase of dynamic MRI could be reliable MR features for the diagnosis of AIP in the proximal pancreas by allowing its differentiation from PDAC. • The icicle sign of the pancreatic duct is useful for diagnosing AIP. • Mild T1 hypointensity similar to the spleen is useful for diagnosing AIP. • Isointensity on portal and late phases MRI is useful for diagnosing AIP.

A Posterior Fossa Epidermoid Cyst without Restriction by DWI, A Rare Finding

Objective: To present the typical, and in this case, atypical MRI DWI findings of a posterior fossa epidermoid cyst. Design/Patient/Material: A single case of a 27 year old female with a one year history of intermittent vertigo, and an epidermoid cyst with unusual T1 and T2 MRI findings, without DWI restriction. Methods: Comparison of this case to a “typical” epidermoid cyst of the posterior fossa imaged with standard MRI including DWI. Results: Our case showed unusual T1 hyperintensity and T2 isointensity, without DWI restriction. Conclusion: Posterior fossa epidermoid cysts typically present with low T1 and high T2 values, with DWI restriction. However, as our case demonstrates, this tumor may present with a rare lack of DWI restriction, and aberrant T1 and T2 values, probably due to unusual protein or blood product components.

Extradural spinal cord lesion in a dog: First case study of canine neurological histoplasmosis in Italy

A 7-year-old intact male mixed dog was presented with a history of acute and progressive paraparesis. Abnormal clinical signs consisted of non-ambulatory paraparesis, hind limbs hypertonia and severe thoracolumbar pain. Magnetic resonance imaging demonstrated an isointense in T1 and T2 WI epidural lesion, with good contrast enhancement, extending from T-10 to T-13. Laminectomy was carried out to remove the epidural mass. Histological examination revealed a pyogranulomatous lesion characterized by numerous macrophages containing yeast-like Grocott and PAS-positive bodies. Immunohistochemistry and PCR performed on formalin-fixed paraffin-embedded tissue confirmed Histoplasma capsulatum as the causative agent.H. capsulatum has a worldwide distribution in temperate and subtropical climates but its presence as an autochthonous fungus in Europe is now recognized. To the authors’ knowledge this is the first report of canine histoplasmosis in Italy with lesion confined to the central nervous system.

Magnetic Resonance Image Manifestations of the Atypical Meningioma

Through retrospective analysis of 13 cases of magnetic resonance image (MRI) manifestations of atypical meningiomas confirmed by operation and pathology in the First Affiliated Hospital of Xinxiang Medical University, the objective of this study was to evaluate the diagnostic value of MRI in order to improve the accuracy rate of preoperative diagnosis. In this retrospective analysis of MRI findings for atypical meningiomas in First Affiliated Hospital of Xinxiang Medical University from January to July in 2012, the location, morphology and tumor signals and other tumor imaging characteristics were covered. In 13 cases of atypical meningioma patients of this group, most tumors were located at typical sites (10/13), mainly the falx cerebri, parasagittal, convexity, saddle area. Only two cases were at atypical locations, 1 in the cerebellar hemisphere and 1 in a lateral ventricle. Most of the tumors showed T1 and T2 isointensity signals, and necrosis, calcification, and peritumoral edema were always featured. DWI showed isointensity in 11 cases (11/13), and hyperintensity in 2. Some 9 cases had dural tail signs, 12 had accurate positioning (12/13), and 2 were postoperative recurrences. MRI has high value in the diagnosis of atypical meningiomas, with important roles in early clinical diagnosis, treatment and prognosis evaluation.

Integration of sparse multi-modality representation and anatomical constraint for isointense infant brain MR image segmentation

Segmentation of infant brain MR images is challenging due to poor spatial resolution, severe partial volume effect, and the ongoing maturation and myelination processes. During the first year of life, the brain image contrast between white and gray matters undergoes dramatic changes. In particular, the image contrast inverses around 6–8months of age, where the white and gray matter tissues are isointense in T1 and T2 weighted images and hence exhibit the extremely low tissue contrast, posing significant challenges for automated segmentation. In this paper, we propose a general framework that adopts sparse representation to fuse the multi-modality image information and further incorporate the anatomical constraints for brain tissue segmentation. Specifically, we first derive an initial segmentation from a library of aligned images with ground-truth segmentations by using sparse representation in a patch-based fashion for the multi-modality T1, T2 and FA images. The segmentation result is further iteratively refined by integration of the anatomical constraint. The proposed method was evaluated on 22 infant brain MR images acquired at around 6months of age by using a leave-one-out cross-validation, as well as other 10 unseen testing subjects. Our method achieved a high accuracy for the Dice ratios that measure the volume overlap between automated and manual segmentations, i.e., 0.889±0.008 for white matter and 0.870±0.006 for gray matter.

SODIUM ACCUMULATION IS ASSOCIATED WITH DISABILITY AND PROGRESSION IN MULTIPLE SCLEROSIS: A 23NA MRI STUDY

IntroductionNeuroaxonal loss is the major pathological substrate of irreversible disability in Multiple Sclerosis (MS). Sodium is maintained at lower concentration within the intra–axonal space by the Na/K/ATPase pump. In MS,...

Giant ecchordosis physaliphora in an adolescent girl

The authors describe a rare case of giant ecchordosis physaliphora (EP) in a 16-year-old female patient who presented with diplopia. Magnetic resonance imaging of the brain with Gd contrast revealed a 3.0 × 1.7 × 1.8-cm nonenhancing, extraaxial epidural mass along the dorsal aspect of the clivus that was T2 hyperintense and T1 isointense with intermediate signal on diffusion sequences. Resection via a transnasal transsphenoidal approach to the ventral clival wall resulted in a stable tumor size with no evidence of interval growth after 30 months. Although this case features a strictly extradural EP, this tumor more commonly occurs in the subdural space and requires differentiation from intradural chordoma. Unlike EP, intradural chordoma may enhance with Gd contrast, is more likely to be associated with cranial nerve palsies and brainstem symptoms, and will occasionally have an elevated MIB-1 index. In this paper the authors highlight the different possible midline locations for both EP and chordoma, the difficulty in distinguishing between intradural giant EP and intradural chordoma, and the potential occurrence of these lesions in young people despite their typically slow rate of growth, while also underscoring the need for further investigation into the tumors' cytogenetic behavior.