Brain tumor classification using the diffusion tensor image segmentation (D-SEG) technique.

BACKGROUND: There is an increasing demand for noninvasive brain tumor biomarkers to guide surgery and subsequent oncotherapy. We present a novel whole-brain diffusion tensor imaging (DTI) segmentation (D-SEG) to delineate tumor volumes of interest (VOIs) for subsequent classification of tumor type. D-SEG uses isotropic (p) and anisotropic (q) components of the diffusion tensor to segment regions with similar diffusion characteristics. METHODS: DTI scans were acquired from 95 patients with low- and high-grade glioma, metastases, and meningioma and from 29 healthy subjects. D-SEG uses k-means clustering of the 2D (p,q) space to generate segments with different isotropic and anisotropic diffusion characteristics. RESULTS: Our results are visualized using a novel RGB color scheme incorporating p, q and T2-weighted information within each segment. The volumetric contribution of each segment to gray matter, white matter, and cerebrospinal fluid spaces was used to generate healthy tissue D-SEG spectra. Tumor VOIs were extracted using a semiautomated flood-filling technique and D-SEG spectra were computed within the VOI. Classification of tumor type using D-SEG spectra was performed using support vector machines. D-SEG was computationally fast and stable and delineated regions of healthy tissue from tumor and edema. D-SEG spectra were consistent for each tumor type, with constituent diffusion characteristics potentially reflecting regional differences in tissue microstructure. Support vector machines classified tumor type with an overall accuracy of 94.7%, providing better classification than previously reported. CONCLUSIONS: D-SEG presents a user-friendly, semiautomated biomarker that may provide a valuable adjunct in noninvasive brain tumor diagnosis and treatment planning.

Evaluation of neck pain with (18)F-NaF PET/CT.

AIM: (18)F-Sodium fluoride ((18)F-NaF) PET/computed tomography (CT) has improved spatial resolution in the cervical spine compared with single photon emission computed tomography/CT techniques using traditional tracers. Limited data are available, however, on its effectiveness in the management of the symptomatic cervical spine, and the aim of this study was therefore to elucidate this issue. PATIENTS AND METHODS: A retrospective study was carried out between April 2011 and April 2012. Across this period, 66 patients were referred to the department for the assessment of neck pain, of whom 58 were included in the study. (18)F-NaF was used as the tracer and images were acquired on an integrated PET/CT scanner. All studies were evaluated by either consultant nuclear medicine physicians or by a radiologist. Two consultant neurosurgeons correlated the imaging reports with the clinical data from the patient notes to give an overall impression as to how beneficial the test had been with regard to patient management. RESULTS: In 49/58 (84.5%) cases, the (18)F-NaF PET/CT report was thought to have been clinically useful in patient management. In 9/58 (15.5%) cases, the report was thought not to have been clinically beneficial, generally because of high background vertebral uptake of (18)F-fluoride secondary to degenerative disease. CONCLUSION: As our experience with (18)F-NaF PET/CT broadens, we believe that it will become an increasingly important tool in the evaluation and management of the symptomatic cervical spine.

Inversion therapy in patients with pure single level lumbar discogenic disease: a pilot randomized trial.

PURPOSE: Backache and sciatica due to protuberant disc disease is a major cause of lost working days and health expenditure. Surgery is a well-established option in the management flowchart. There is no strong evidence proving that traction for sciatica is effective. We report a pilot prospective randomized controlled trial comparing inversion traction and physiotherapy with standard physiotherapy alone in patients awaiting lumbar disc surgery. This study sought to study the feasibility of a randomized controlled trial on the effect of inversion therapy in patients with single level lumbar discogenic disease, who had been listed for surgery. METHODS: This was a single centre prospective randomized controlled trial undertaken at the Regional Neurosciences Centre, Newcastle Upon Tyne, UK. It was a prospective randomized controlled trial where patients awaiting surgery for pure lumbar discogenic disease within the ambit of the prestated inclusion/exclusion criteria were allocated to either physiotherapy or physiotherapy and intermittent traction with an inversion device. Post-treatment assessment made by blinded observers at 6 weeks for various outcome measures included the Roland Morris Disability Questionnaire (RMDQ) Score, Short Form 36 (SF 36), Oswestry Disability Index (ODI), Visual Analogue Pain Score (VAS), magnetic resonance imaging (MRI) appearance and the need for surgery. Avoidance of surgery was considered a treatment success. RESULTS: Twenty-six patients were enrolled and 24 were randomized [13 to inversion + physiotherapy and 11 to physiotherapy alone (control)]. Surgery was avoided in 10 patients (76.9%) in the inversion group, whereas it was averted in only two patients (22.2%) in the control group. Cancellation of the proposed operation was a clinical decision based on the same criteria by which the patient was listed for surgery initially. There were no significant differences in the RMDQ, SF 36, ODI, VAS or MRI results between the two groups. CONCLUSION: Intermittent traction with an inversion device resulted in a significant reduction in the need for surgery. A larger multicentre prospective randomized controlled trial is justified in patients with sciatica due to single level lumbar disc protrusions. [ IMPLICATIONS FOR REHABILITATION: • Resolution of impairment and diasability due to radiculopathy is the aim of any intervention.• Avoidance of surgery meant satisfactory resolution of impairment and disability due to radiculopathy. This happened more often in the inversion group to the extent of reaching statistical significance.• The 12-point improvement in disability by the Oswestry Disability Index in the inversion group suggests a role for this intervention in disability reduction.• Inversion may form part of the conservative rehabilitation of patients with single level unilateral lumbar disc protrusion alongside other forms of physiotherapy.• There is a potential secondary impact in the reduction of rehabilitation following surgery.]

Diffusion tensor imaging discriminates between glioblastoma and cerebral metastases in vivo.

In a prospective study, patients with a radiologically proven brain tumour underwent diffusion tensor imaging (DTI) prior to definitive diagnosis and treatment. Twenty-eight patients with a histologically proven glioblastoma or metastasis were included in the study. Following the definition of regions of interest, DTI metrics [mean diffusivity (MD) and fractional anisotropy (FA)] were calculated for the tumour volume and the surrounding region of peritumoral oedema. These metrics were then subjected to logistic regression to investigate their ability to discriminate between glioblastomas and cerebral metastases. A cross-validation was performed to investigate the ability of the model to predict tumour. The logistic regression analysis correctly distinguished glioblastoma in 15 of 16 cases (93.8%) and metastasis in 11 of 12 cases (91.7%). Cross-validation resulted in the model correctly predicting 14 of 16 (87.5%) glioblastomas and 10 of 12 (83.3%) metastases studied. MD was significantly higher (p = 0.02) and FA was significantly lower (p = 0.04) within the oedema surrounding metastases than within the oedema around glioblastomas. MD was significantly higher (p = 0.02) within the tumour volume of the glioblastomas. Our results demonstrate that, when DTI metrics from the tumour volume and surrounding peritumoral oedema are studied in combination, glioblastoma can be reliably discriminated from cerebral metastases.

Semiautomatic tractography: motor pathway segmentation in patients with intracranial vascular malformations. Clinical article.

OBJECT: The visualization of white matter tracts using tractography has previously been achieved by displaying streamlines that pass between regions of interest (ROIs). These techniques require a significant amount of user interaction, and their results are entirely dependent on the positioning of the ROIs. Furthermore, in patients with intracerebral hemorrhage secondary to intracranial vascular malformation, there is often significant cerebral edema and susceptibility artifact from the hematoma, which degrade the reliability of tractography. In this paper, the authors' objectives were to visualize the motor pathways of patients with hemorrhagic and nonhemorrhagic vascular malformations by using a novel semiautomated technique that functions without the need for multiple ROIs. METHODS: The authors investigated the tractography appearance of the descending motor pathways in 6 patients with intracranial vascular malformations. Of these patients 4 presented with a spontaneous intracranial hemorrhage, 2 of whom were clinically hemiparetic. Diffusion tensor imaging was performed using a 1.5-T clinical MR imaging system, and whole-brain tractography was performed after reconstruction of the data. A fractional anisotropy threshold of 0.05 was used to terminate the tractography. The semiautomatic motor pathway segmentation technique required definition of a single voxel within the corticospinal tract of the medulla from which the descending motor pathways were automatically defined by grouping together all streamlines within the entire image with a geometry similar to that of the single streamline generated from this initial voxel. The results of this segmentation were then visually assessed and compared with the patient's motor function. RESULTS: The authors' semiautomatic algorithm consistently visualized the location of the descending motor pathways in patients with nonhemorrhagic and hemorrhagic vascular malformations. In 1 patient whose complete right hemiplegia (complete paralysis) was caused by a large left frontal hematoma that bisected the descending motor pathways, the authors were unable to reconstruct the motor pathways due to severe tract degeneration. However, in all cases in which motor function was intact or only mildly impaired, the technique clearly delineated the motor pathways, even in the presence of large anatomical displacement by the vascular abnormality or associated hemorrhage. CONCLUSIONS: Semiautomatic tractography allows consistent and rapid demonstration of the descending motor pathways in patients with hemorrhagic and nonhemorrhagic intracranial vascular malformations. The technique allows the use of a comparatively low fractional anisotropy threshold and does not require the definition of multiple ROIs. These techniques may help to improve the clinical feasibility and potentially the reliability of tractography for the evaluation of patients with intracranial vascular malformations as well as other space-occupying lesions of the brain.