In vivo magnetic resonance spectroscopy for the differential diagnosis of a cerebral mass in a boy with precocious puberty: a case report and review of the literature.

PURPOSE: To highlight the role of in vivo magnetic resonance spectroscopy (MRS) as a non-invasive tool that can clarify the etiology of sellar tumors by presenting the case of a boy with central precocious puberty (CPP) and to review the current literature. METHODS: A 4-year-old boy was admitted to our hospital due to repeated episodes of focal and gelastic seizures in the previous year. Clinical examination (testicular volume 4-5 ml bilaterally, penile length of 7.5 cm, and absence of axillary or pubic hair) and laboratory tests (FSH, LH, and testosterone) were indicative of CPP. The combination of gelastic seizures with CPP in a 4-year-old boy raised the suspicion of hypothalamic hamartoma (HH). Brain MRI revealed a lobular mass in the suprasellar-hypothalamic region. The differential diagnosis included glioma, HH, and craniopharyngioma. To further investigate the CNS mass, an in vivo brain MRS was performed. RESULTS: Οn conventional MRI, the mass demonstrated isointensity to gray matter on T1 weighted images but slight hyperintensity on T2-weighted images. It did not show restricted diffusion or contrast enhancement. On MRS, it showed reduced N-acetyl aspartate (NAA) and slightly elevated myoinositol (MI) compared with values in normal deep gray matter. The MRS spectrum, in combination with the conventional MRI findings, were consistent with the diagnosis of a HH. CONCLUSION: MRS is a state-of-the-art, non-invasive imaging technique that compares the chemical composition of normal tissue to that of abnormal regions by juxtaposing the frequency of measured metabolites. MRS, in combination with clinical evaluation and classic MRI, can provide identification of CNS masses, thus eliminating the need for an invasive biopsy.

Survey of automated multiple sclerosis lesion segmentation techniques on magnetic resonance imaging.

Multiple sclerosis (MS) is a chronic disease. It affects the central nervous system and its clinical manifestation can variate. Magnetic Resonance Imaging (MRI) is often used to detect, characterize and quantify MS lesions in the brain, due to the detailed structural information that it can provide. Manual detection and measurement of MS lesions in MRI data is time-consuming, subjective and prone to errors. Therefore, multiple automated methodologies for MRI-based MS lesion segmentation have been proposed. Here, a review of the state-of-the-art of automatic methods available in the literature is presented. The current survey provides a categorization of the methodologies in existence in terms of their input data handling, their main strategy of segmentation and their type of supervision. The strengths and weaknesses of each category are analyzed and explicitly discussed. The positive and negative aspects of the methods are highlighted, pointing out the future trends and, thus, leading to possible promising directions for future research. In addition, a further clustering of the methods, based on the databases used for their evaluation, is provided. The aforementioned clustering achieves a reliable comparison among methods evaluated on the same databases. Despite the large number of methods that have emerged in the field, there is as yet no commonly accepted methodology that has been established in clinical practice. Future challenges such as the simultaneous exploitation of more sophisticated MRI protocols and the hybridization of the most promising methods are expected to further improve the performance of the segmentation.

Brain and heart magnetic resonance imaging/spectroscopy in duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is an X-linked muscle disorder characterized by progressive and irreversible loss of muscular function. As muscular disease progresses, the repair mechanisms cannot compensate for cellular damage, leading inevitably to necrosis and progressive replacement by fibrous and fatty tissue. Cardiomyopathy and respiratory failure are the main causes of death in DMD. In addition to the well-described muscle and heart disease, cognitive dysfunction affects around 30% of DMD boys. Myocardial fibrosis, assessed by late gadolinium enhancement (LGE), using cardiovascular magnetic resonance imaging (CMR), is an early marker of heart involvement in both DMD patients and female carriers. In parallel, brain MRI identifies smaller total brain volume, smaller grey matter volume, lower white matter fractional anisotropy and higher white matter radial diffusivity in DMD patients. The in vivo brain evaluation of mdx mice, a surrogate animal model of DMD, showed an increased inorganic phosphate (P(i))/phosphocreatine (PCr) and pH. In this paper, we propose a holistic approach using techniques of magnetic resonance imaging, spectroscopy and diffusion tensor imaging as a tool to create a "heart and brain imaging map" in DMD patients that could potentially facilitate the patients' risk stratification and also future research studies in the field.

Prognostic Value of MRS Metabolites in Postoperative Irradiated High Grade Gliomas.

PURPOSE: We studied the prognostic significance of Magnetic Resonance Spectroscopy (MRS) in operated high grade gliomas. MATERIALS AND METHODS: Twelve patients were treated with radiotherapy and Temozolomide. The MRS data were taken four weeks after operation (before radiotherapy) and every six months after the completion of RT. The N-acetyl aspartate, choline, creatine, and myo-inositol parameters were quantified, analyzed, and correlated to recurrence-free survival (RFS). RESULTS: The median RFS was 26.06 months. RFS was significantly worse in elderly patients (P = 0.001) along with the higher choline/creatine ratios at either baseline (P = 0.003) or six months post Radiotherapy (P = 0.042). Median RFS was 23 months in high choline/creatine levels ≥ 2 at 6 months after radiotherapy and 11 months for those with < 2 choline/creatine levels. There was a significant correlation of maximum difference of choline/creatine ratio with RFS (rho = 0.64, P = 0.045). CONCLUSION: Age and choline/creatine ratio are strong independent prognostic factors in high grade gliomas.

Preoperative evaluation with FMRI of patients with intracranial gliomas.

Introduction. Aggressive surgical resection constitutes the optimal treatment for intracranial gliomas. However, the proximity of a tumor to eloquent areas requires exact knowledge of its anatomic relationships to functional cortex. The purpose of our study was to evaluate fMRI's accuracy by comparing it to intraoperative cortical stimulation (DCS) mapping. Material and Methods. Eighty-seven patients, with presumed glioma diagnosis, underwent preoperative fMRI and intraoperative DCS for cortical mapping during tumor resection. Findings of fMRI and DCS were considered concordant if the identified cortical centers were less than 5 mm apart. Pre and postoperative Karnofsky Performance Scale and Spitzer scores were recorded. A postoperative MRI was obtained for assessing the extent of resection. Results. The areas of interest were identified by fMRI and DCS in all participants. The concordance between fMRI and DCS was 91.9% regarding sensory-motor cortex, 100% for visual cortex, and 85.4% for language. Data analysis showed that patients with better functional condition demonstrated higher concordance rates, while there also was a weak association between tumor grade and concordance rate. The mean extent of tumor resection was 96.7%. Conclusions. Functional MRI is a highly accurate preoperative methodology for sensory-motor mapping. However, in language mapping, DCS remains necessary for accurate localization.

Rapid magnetic heating treatment by highly charged maghemite nanoparticles on Wistar rats exocranial glioma tumors at microliter volume.

One of the most significant challenges implementing colloidal magnetic nanoparticles in medicine is the efficient heating of microliter quantities by applying a low frequency alternating magnetic field. The ultimate goal is to accomplish nonsurgically the treatment of millimeter size tumors. Here, we demonstrate the synthesis, characterization, and the in vitro as well as in vivo efficiency of a dextran coated maghemite (gamma-Fe(2)O(3)) ferrofluid with an exceptional response to magnetic heating. The difference to previous synthetic attempts is the high charge of the dextran coating, which according to our study maintains the colloidal stability and good dispersion of the ferrofluid during the magnetic heating stage. Specifically, in vitro 2 mul of the ferrofluid gives an outstanding temperature rise of 33 degrees C within 10 min, while in vivo treatment, by infusing 150 mul of the ferrofluid in animal model (rat) glioma tumors, causes an impressive cancer tissue dissolution.

Effect of iron overload on exercise capacity in thalassemic patients with heart failure.

In b-thalassemia, myocardial iron overload contributes to heart failure, despite chelation treatment. We hypothesized that myocardial T2*, an index of iron overload, influences patients' physical activity. We assessed a thalassemic population by both cardiovascular magnetic resonance imaging (CMR) and ergospirometry test. Sixty-six thalassemic patients aged 27 (19-40) years, 30 without (NHF) and 36 with heart failure (HF), were studied. Cardiac T2* and left ventricular ejection fraction (LVEF) were evaluated using a 1.5 T system. VO(2max), AT, Mets and duration of exercise by ergospirometry were also assessed. Myocardial T2* was lower in HF compared to NHF patients (14.7 +/- 6.6 vs. 39 +/- 2 ms, P < 0.001). LVEDV and LVESV were higher in HF group compared to NHF patients (139.9 +/- 16.3 vs. 124.6 +/- 20.86 ml, P < 0.01 and 94.9 +/- 24 vs. 38.3 +/- 10.1 ml, P < 0.001, respectively). Additionally, LVEF in HF was lower compared to NHF patients (21.3 +/- 6.1% vs. 69.6 +/- 3.7, P < 0.001, respectively). All exercise parameters were lower in HF compared to NHF patients (P < 0.001). Patients within the HF group were additionally analyzed according to T2* values (<10 ms). HF patients with T2* < 10 ms (n = 13) were considered as high iron overloaded (HF-H) and the rest of them (n = 23) as (HF-L). Although LVEDV, LVESV, LVEF were similar in the two subgroups, the exercise parameters were significantly lower in the HF-H group (P < 0.001). Heart T2* correlated with all exercise parameters (P < 0.001). HF thalassemic patients have reduced exercise indexes compared to non HF. Myocardial iron overload, expressed as T2*, has a direct influence on exercise capacity, independent of LV ejection fraction and functional class.

Magnetic resonance evaluation of liver and myocardial iron deposition in thalassemia intermedia and b-thalassemia major.

INTRODUCTION: b-Thalassemia major (TM) and thalassemia intermedia (TI) are forms of inherited hemoglobinopathies. Our aim was to evaluate a population of asymptomatic TM and TI patients using cardiovascular magnetic resonance (CMR). We hypothesized that the TI group could be differentiated from the TM group based on T2*. We also hypothesized that the TI group would demonstrate significantly higher cardiac output compared to the TM group. PATIENTS AND METHODS: Twenty-one consecutive TI patients aged 23(19-25) years, 21 TM patients and 21 age and sex matched controls were studied. Evaluation of heart, liver T2* relaxation time and right and left ventricular parameters was performed using a 1.5 T system. RESULTS: Myocardial and liver T2* values were significantly higher in TI patients compared to TM (34.35 +/- 2.36 vs 15.77 +/- 3.53 m, P < 0.001 and 5.12 +/- 6.52 vs 1.36 +/- 0.53 ms, P < 0.001, respectively). Controls had myocardial T2* 35.07 +/- 4.52 ms (similar to TI patients, but significantly increased compared to TM patients, P < 0.001) and liver T2* 26.28 +/- 2.37 ms (significantly increased compared to both TI and TM patients, P < 0.001). Left ventricular end-diastolic (LVEDV), end-systolic (LVESV) volumes and left ventricular ejection fraction (LVEF) were higher in TI patients compared to TM (P < 0.001). Stroke volume (LVSV), cardiac output (LVCO) and cardiac index (LVCI) were similarly increased in TI patients compared to TM (P < 0.001). Right ventricular end-diastolic volume (RVEDV), right ventricular end-systolic volume (RVESV) and right ventricular ejection fraction (RVEF) were higher in TI patients compared to TM (P < 0.001). CONCLUSIONS: Although in TM iron plays a crucial role in the evolution of the disease, in TI the high output cardiac state seems to be the most prominent finding.

Myocardial and hepatic T2* magnetic resonance evaluation in ex-thalassemic patients after bone-marrow transplantation.

Bone marrow transplantation (BMT) is the only complete cure for b-thalassemia. Iron depletion therapy is still required to remove excess iron, accumulated before BMT. Hepatic and myocardial iron load were evaluated using T2* magnetic resonance in 8 ex-thalassemic patients after BMT, aged 19.5 +/- 4.25 years, who were in iron depletion therapy. Average hepatic T2* was 18.8 +/- 11.0 msec (4.1-35.0 msec). In 4 out of 8 patients iron overload was detected, not exceeding however 4 mg/gr dry tissue. Average heart T2* was 31.0 +/- 4.6 msec (25.6-35.2 msec), not significantly different (P = 0.18) from our age-matched normal population (33.0 +/- 4.0). Normal left ventricular ejection fraction was found in 7 out of 8 patients (mean 64.5 +/- 7.0%) with the remaining having a marginal value of 54.1%. Ferritin level before BMT was 1748 +/- 451 mug/l and dropped to 536 +/- 260 microg/l at the end of iron depletion therapy after BMT. Current ferritin level was 271 +/- 253 microg/l and although it was significant lower compared to both ferritin before BMT (P < 0.001) and after iron depletion (P < 0.001), evidence of residual hepatic iron load was identified by T2*. Hepatic and myocardial T2* magnetic resonance can be used as a more reliable index than ferritin for evaluation of iron depletion therapy in ex-thalassemic patients after BMT.