Golden-Angle Radial Sparse Parallel (GRASP) MRI differentiates head & neck paragangliomas from schwannomas.

PURPOSE: The aim of this study was to demonstrate the value of DCE MRI with high spatiotemporal resolution (GRASP) for differentiating paragangliomas and schwannomas in the head and neck. METHODS: In a retrospective PACS search of in total 410 patients who had undergone head & neck GRASP-MRI, we identified 6 patients with biopsy proven cervical paragangliomas (n = 3) and schwannomas (n = 3). Conventional MRI features were evaluated, lesion size was determined. Postprocessing in 4D-GRASP datasets was performed (1) based on reconstructions with a temporal resolution (Tres) of 4.1 s, qualitative time-intensity curve classification and semiquantitative parameter (Tpeak, PH, ERmax and Slopemax) analysis, and (2) voxel-based mapping and qualitative and semiquantitative perfusion modeling based on reconstructions with a Tres of 1.6 s. Additionally, GRASP perfusion analysis was performed in another set of 5 patients with presumed cervical paragangliomas (n = 3) and schwannomas (n = 2) based on conventional imaging criteria and was correlated with conventional imaging findings. Due to the small sample size, both groups were compared qualitatively. RESULTS: In the time intensity curve classification of 4D GRASP reconstructions (Tres 4.1 s), biopsy proven paragangliomas were consistently characterized by a type-III rapid inflow wash-out pattern, compared to a type-I inflow pattern in the schwannoma group. In both temporal resolutions, semiquantitative analysis of time intensity curves demonstrated rapid wash-in, wash-out, and higher peak signal intensities in paragangliomas compared to schwannomas. In 5 presumed (non-biopsy-proven) paragangliomas and schwannomas, time intensity curves improved diagnostic certainty. CONCLUSIONS: Visual time intensity curve classification and semi-quantitative analysis of GRASP-MRI were, in this small retrospective series, sufficient to differentiate cervical paragangliomas from schwannomas. Utilization of this technique may further improve diagnostic confidence in lesions lacking conventional imaging features.

Non-uniform muscle fat replacement along the proximodistal axis in Duchenne muscular dystrophy.

The progressive replacement of muscle tissue by fat in Duchenne muscular dystrophy (DMD) has been studied using quantitative MRI between, but not within, individual muscles. We studied fat replacement along the proximodistal muscle axis using the Dixon technique on a 3T MR scanner in 22 DMD patients and 12 healthy controls. Mean fat fractions per muscle per slice for seven lower and upper leg muscles were compared between and within groups assuming a parabolic distribution. Average fat fraction for a small central slice stack and a large coverage slice stack were compared to the value when the stack was shifted one slice (15 mm) up or down. Higher fat fractions were observed in distal and proximal muscle segments compared to the muscle belly in all muscles of the DMD subjects (p <0.001). A shift of 15 mm resulted in a difference in mean fat fraction which was on average 1-2% ranging up to 12% (p <0.01). The muscle end regions are exposed to higher mechanical strain, which points towards mechanical disruption of the sarcolemma as one of the key factors in the pathophysiology. Overall, this non-uniformity in fat replacement needs to be taken into account to prevent sample bias when applying quantitative MRI as biomarker in clinical trials for DMD.

Fertility preservation in women with early stage cervical cancer. Review of the literature.

Within the last decades, the percentage of diagnosed cervical cancer in women of reproductive age has increased. The possibility of diagnosing small cervical tumors (< or = twocm) in childbearing age, can be explained due to the fact that many women, are aware of the benefits of Pap smear or colposcopy examination. Many demand a more conservative policy to handle such lesions in order to have an uneventful pregnancy in the near future.

Cyclic peptide analogs of 558-565 epitope of A2 subunit of Factor VIII prolong aPTT. Toward a novel synthesis of anticoagulants.

Novel anticoagulant therapies target specific clotting factors in blood coagulation cascade. Inhibition of the blood coagulation through Factor VIII-Factor IX interaction represents an attractive approach for the treatment and prevention of diseases caused by thrombosis. Our research efforts are continued by the synthesis and biological evaluation of cyclic, head to tail peptides, analogs of the 558-565 sequence of the A2 subunit of FVIII, aiming at the efficient inhibition of Factor VIIIa-Factor IXa interaction. The analogs were synthesized on solid phase using the acid labile 2-chlorotrityl chloride resin, while their anticoagulant activities were examined in vitro by monitoring activated partial thromboplastin time and the inhibition of Factor VIII activity. The results reveal that these peptides provide bases for the development of new anticoagulant agents.

Local and global fiber tractography in patients with epilepsy.

BACKGROUND AND PURPOSE: Fiber tractography is increasingly used in the preoperative evaluation of endangered fiber bundles. From a clinical point of view, an accurate and methodologically transparent procedure is desired. Our aim was to evaluate the recently described global tracking algorithm compared with other established methods, such as deterministic and probabilistic tractography. MATERIALS AND METHODS: Twenty patients, candidates for excision of epileptogenic lesions, were subjected to higher-angular resolution diffusion imaging-based fiber tractography. Seed points were created without manual bias, predominantly by FreeSurfer and voxel-based atlases. We focused on 2 important fiber bundles, namely the descending motor pathways and the optic radiation. Postoperatively, the accuracy of the predicted fiber route was controlled by structural MR imaging and by inflicted functional deficits. RESULTS: Among the 3 evaluated methods, global tracking was the only method capable of reconstructing the full extent of the descending motor pathways, including corticobulbar fibers from the area of face representation. Still, probabilistic tractography depicted the optic radiation better, especially the Meyer loop. The deterministic algorithm performed less adequately. CONCLUSIONS: The probabilistic method seems to be the best balance between computational time and effectiveness and seems to be the best choice in most cases, particularly for the optic radiation. If, however, a detailed depiction of the fiber anatomy is intended and tract crossings are implicated, then the computationally time-consuming global tracking should be preferred.

Effect of tamoxifen on postmenopausal endometrium.

PURPOSE: The objective of this study was to evaluate the effect oftamoxifen on the endometrium of45 postmenopausal women with breast cancer, as evidenced by hysteroscopic, ultrasound, histological methods, and by immunohistochemical investigation of the expression of Bcl-2 and Ki67. MATERIALS AND METHODS: Forty-five postmenopausal women with breast cancer (ER and/or PgR positive) undergoing tamoxifen therapy for six to 48 months, were selected from the files of the 2nd Department of Obstetrics and Gynecology, University of Athens Aretaieion Hospital, among a total of 120 patients treated from 2004-2009. RESULTS: The ultrasound findings during the follow-up period revealed 18 cases of thickened endometrium, 14 cases of suspected polyps, one case with accumulation of endometrial fluid, and 12 cases of heterogeneous endometrial echo texture. The patients had undergone hysteroscopy because of thickened endometrium (18/45 patients), postmenopausal bleeding (14/45 patients), and polyps (13/45 patients). The endometrial tissue samples were examined in the Pathology Department of Aretaieion Hospital and showed in 23 cases with adenomatous endometrial polyps, 15 cases with endometrial cystic atrophy, two cases with adenomatous hyperplasia, and five cases with mucosal endometrial adhesions. Immunohistochemical investigation of Bcl-2 and KJ67 expression was undertaken on paraffin blocks and showed elevated expression in the cases with endometrial polyps and hyperplasia, in contrast to atrophic endometria. CONCLUSION: Long-term tamoxifen therapy of postmenopausal women with breast cancer is associated with uterine pathology. Ultrasonography alone is useful in asymptomatic patients selecting cases with increased endometrial thickness for further investigation. Hysteroscopy is an accurate method for diagnosing endometrial disease because it provides a direct view of the uterine cavity, reveals focal lesions, and enables targeted biopsies to be performed at the same time. Pathological findings show elevated expression of Ki67 and Bcl-2 in hyperplastic endometria and adenomatous polyps, consistent with an elevated glandular cell proliferation due to tamoxifen effect.

A novel approach in potential anticoagulants from peptides epitope 558-565 of A2 subunit of factor VIII.

Factor VIII, a human blood plasma protein, plays an important role during the intrinsic pathway of blood coagulation cascade after its activation by thrombin. The activated form of FVIII acts as cofactor to the serine protease Factor IXa, in the conversion of the zymogen Factor X to the active enzyme Factor Xa. The Ser558-Gln565 region of the A2 subunit of Factor VIII has been shown to be crucial for FVIIIa-FIXa interaction. Based on this, a series of linear peptides, analogs of the 558-565 loop of the A2 subunit of the heavy chain of Factor VIII were synthesized using the acid labile 2-chlorotrityl chloride resin and biologically evaluated in vitro by measuring the chronic delay of activated partial thromboplastin time and the inhibition of Factor VIII activity, as potential anticoagulants.

Global tracking in human gliomas: a comparison with established tracking methods.

PURPOSE: Global tracking (GT) is a recently published fibre tractography (FT) method that takes simultaneously all fibres into account during their reconstruction. The purpose of this study was to compare this new method with fibre assignment by continuous tracking (FACT) and probabilistic tractography (PT) for the detection of the corticospinal tract (CST) in patients with gliomas. METHODS: Tractography of the CST was performed in 17 patients with eight low grade and nine anaplastic astrocytomas located in the motor cortex or the corticospinal tract. Diffusions metrics as fractional anisotropy (FA), mean (MD), axial (AD) and radial diffusivity (RD) were obtained. The methods were additionally applied on a physical phantom to assess their accuracy. RESULTS: PT was successful in all (100 %), GT in 16 (94 %) and FACT in 15 patients (88 %). The case where GT and FACT, both, missed the CST showed the highest AD and RD, whereas the one where FACT algorithm, alone, was not successfully showed the lowest AD and RD of the group. FA was reduced on the pathologic side (FApath 0.35 ± 0.16 (mean ± SD) versus FAcontralateral 0.51 ± 0.15, pcorr < 0.03). RD was increased on the pathologic side (RDpath 0.67 ± 0.29 × 10(-3) mm(2)/s versus RDcontralateral 0.46 ± 0.08 × 10(-3) mm(2)/s, pcorr < 0.03). In the phantom measurement, only GT did not detect false positive fibres at fibre crossings. CONCLUSION: PT performed well even in areas of increased diffusivities indicating a severe oedema or disintegration of tissue. FACT was also susceptible to a decrease of diffusivities and to a susceptibility artefact, where GT was robust.