This study investigated the influence of slice thickness, section orientation, contrast, shape, and sequence type on the exactness of MRI-based volumetry. Ni-doped agarose gel phantoms (4 to 46 ml) were scanned with a T1-weighted three-dimensional Fourier transform (FT) fast low-angle shot (FLASH) and a multiecho two-dimensional FT-Turbo spin-echo (SE) sequence. After segmentation with a three-dimensional region-growing algorithm, the geometric volume was measured considering the partial volume effect. The variability coefficient (Pearson) was .7%. The volumetric error increased with slice thickness, depending on the size and form of the object. Cross sections resulted in smaller error than longitudinal sections (finger-shaped phantoms, nonisotropic image data). Three-dimensional FT imaging. Results of slice thickness and section orientation experiments can be explained by the partial volume effect Higher errors in two-dimensional FT imaging were caused by object movements between two interleaved acquisitions. The study shows a considerable influence of the imaging parameters on the exactness, which depends on size and form of the structure of interest.

Algorithms↗

PubMedDate not supplied

Imaging and graphics in medicine: concept of an object-oriented platform for clinical research.

We present a workstation-based research platform with two major components. A turnkey application system provides a functionality kernel for a broad community of clinical users with an interest in digital imaging. A development toolbox allows efficient implementation of research ideas and consistent integration of new applications with the common framework of the turnkey system. The platform is based on an elaborate object class structure describing objects for image processing, computer graphics, study handling and user interface control. Thus expertise of computer scientists familiar with this application domain is brought into the hospital and can be readily used by clinical researchers.

Computer Graphics↗

PubMedDate not supplied

Medical workstations for applied imaging and graphics research.

We present a medical workstation for the efficient implementation of research ideas related to image processing and computer graphics. Based on standard hardware platforms the software system encompasses two major components: A turnkey application system provides a functionally kernel for a broad community of clinical users working with digital imaging devices, including methods of noise suppression, interactive and automatic segmentation, 3D surface reconstruction and multi-modal registration. A development toolbox allows new algorithms and applications to be efficiently implemented and consistently integrated with the common framework of the turnkey system. The platform is based on an elaborate object class structure describing objects for image processing, computer graphics, study handling and user interface control. Thus expertise of computer scientists familiar with this application domain is brought into the hospital and can be readily used by clinical researchers.

Algorithms↗

PubMedDate not supplied

Functional capacity, obesity and hypothalamic involvement: cross-sectional study on 212 patients with childhood craniopharyngioma.

The aim of this study was to analyze the impact of hypothalamic involvement of craniopharyngioma on functional capacity (FC) and obesity in 212 patients with childhood craniopharyngioma. FC could be evaluated using an ability scale (Fertigkeitenskala Münster-Heidelberg [FMH]) in 174 patients with childhood craniopharyngioma. Obesity was quantified in 212 patients at the time of diagnosis and at the time of latest evaluation by body mass index SDS [BMI]. The influence of hypothalamic tumor involvement on FC and BMI was analyzed. Patients with hypothalamic involvement (n = 125) presented with higher BMI SDS at the time of diagnosis (p = 0.001) and at latest follow-up evaluation (p < 0.001). FC as measured by FMH percentiles was lower (p < 0.001) in patients with hypothalamic involvement when compared with patients without hypothalamic involvement. FC negatively correlated (p < 0.001) with BMI SDS (Spearman's Rho = -0.40) only in patients with hypothalamic involvement whereas no correlation between FC and BMI SDS was found in patients without hypothalamic involvement. We conclude that hypothalamic involvement of childhood craniopharyngioma had major impact on FC in survivors. Obesity resulted in impaired FC of patients with hypothalamic involvement. BMI at diagnosis was a sensitive parameter to identify patients at risk of severe obesity. Further analysis on this issue is performed in the prospective, multicenter surveillance study on children and adolescents with craniopharyngioma (KRANIOPHARYNGEOM 2000).

Adolescent↗

PubMedDate not supplied

Prognosis and sequela in patients with childhood craniopharyngioma -- results of HIT-ENDO and update on KRANIOPHARYNGEOM 2000.

The overall survival rate of patients with craniopharyngioma, an embryogenic malformation, is high (0.92 +/- 0.03). However, there is considerable morbidity and impaired quality of life, even when the tumor can be completely resected. Aim of our study was to analyze risk factors for severe obesity (body mass index [BMI] > or = 7 SD) and the prognosis of severely obese survivors of childhood craniopharyngioma recruited in our cross-sectional study on 183 patients (HIT-ENDO) and in the prospective study KRANIOPHARYNGEOM 2000. Severe obesity (BMI > or = 7 SD) was present in 16 % of patients and associated with higher tumor volume (p < 0.05), more frequent neurosurgical interventions (p < 0.05) and a higher rate of hypothalamic involvement (p < 0.001). Self-assessed functional capacity (FMH) was lower (p < 0.001) in severely obese survivors (FMH: median 33, range: 4-64) when compared with normal weight patients (FMH: 50; 1-95). Overall survival (20 years) was lower (p = 0.034) in patients with severe obesity in comparison to patients with moderate obesity and normal weight. Cardiovascular morbidity and mortality was high in severely obese patients. Between 10/01 and 03/04 fifty-seven patients (27 female/30 male) were recruited in KRANIOPHARYNGEOM 2000 (www.kraniopharyngeom.com). The impact of tumor localization (3.2 % intrasellar, 22.6 % suprasellar, 74.2 % combined intra/suprasellar; 51.6 % hypothalamic involvement) and treatment (26 complete resections, 22 partial resections followed by irradiation in one case; primary irradiation after biopsy in one case) on quality of life, functional capacity and prognosis will be evaluated longitudinally and prospectively.

Adolescent↗

PubMedDate not supplied

Relapse pattern after complete resection and early progression after incomplete resection of childhood craniopharyngioma.

In HIT Endo data on therapy and prognosis of 306 patients with childhood craniopharyngioma (CP) were analyzed. The 5 years-overall survival rate was 94 +/- 4 % in irradiated patients and 93 +/- 5 % in non-irradiated patients. Aims of the prospective study KRANIOPHARYNGEOM 2000 were to collect data on the incidence and time course of relapses after complete surgery and tumour progressions after incomplete resection. Furthermore, the impact of irradiation therapy (XRT) on tumour relapse and recurrence rates was analyzed. Since 2001 ninety-eight patients with CP were recruited at a median age at diagnosis of 9.9 years ranging from 1.8 to 18.0 years. Complete resection was achieved in 44 %, incomplete resection in 54 %. XRT was performed in 24 of 98 CP patients; in 10 early after incomplete resection, in 14 of 24 after progression of residual tumour or relapse, in 3 of 14 after second surgery of relapse. XRT was performed at a median age of 12.0 years ranging from 5.0 to 18.9 years and in median after an interval of 9 months after first diagnosis. The analysis of event-free survival rates (EFS) in patients with CP showed a high rate of early events in terms of tumour progression after incomplete resection (3y-EFS: 0.22 +/- 0.09) and relapses after complete resection (3y-EFS: 0.60 +/- 0.10) during the first three years of follow-up. A high rate of early events (1y-EFS: 0.78 +/- 0.10; 2y-EFS: 0.57 +/- 0.15) was also found for patients after XRT (3 cystic progressions, 3 progressions of solid tumour; in 24 patients after XRT). We conclude that tumour progression and relapse are frequent and early events even in irradiated patients. Monitoring of cerebral imaging and clinical status is recommended in follow-up of patients with childhood CP. In order to analyze the appropriate time point of XRT after incomplete resection, QoL, EFS and overall survival in patients (age > or = 5 years) will be analyzed in KRANIOPHARYNGEOM 2007 after stratified randomization of the time point of irradiation after incomplete resection (early irradiation versus irradiation at progression of residual tumour).

Adolescent↗

PubMedDate not supplied

Patterns of age-related shrinkage in cerebellum and brainstem observed in vivo using three-dimensional MRI volumetry.

This study investigates the time course and regional differences in age-related volume loss in cerebellum and brainstem. Three-dimensional (3D) magnetic resonance imaging (MRI) volumetry was used to measure the volumes of 11 regions in the cerebellum and three regions in the brainstem in 48 healthy volunteers (age 19.8-73.1 years). Landmark-adjusted lattices were used to divide the cerebellum into three radial (lobules I-V = lingula/lobulus/culmen, lobules VI-VII = declive/folium/tuber, lobules VIII-X = pyramis/uvula/nodulus) and three transverse subdivisions (vermis, medial, lateral hemisphere). The radial sectors extended laterally throughout the vermis and the medial hemisphere. The brainstem was divided into midbrain, metencephalon (pons and tegmentum pontis) and medulla. Total cerebellar volume marginally declined with age using a linear regression model. An exponential model better described the age dependency of total cerebellar volume. The curve predicted that the volume remained stable until age 50 years and declined thereafter. Volume loss in the cerebellar vermis was striking. Shrinkage in the medial hemisphere was markedly less and only the inferior sector showed a trendwise negative association with age. The lateral hemisphere was not affected by age. No age effects were found for total brainstem volume, metencephalon and medulla. Only the mid-brain showed a trend for age-related shrinkage. The mediolateral gradient of decreasing age effects is similar to the histological pattern of alcoholic cerebellar atrophy (although our subjects were non-alcoholics according to DSM-IIIR criteria and laboratory data) suggesting that a common factor is involved in both processes. In search for a cause of the regional vulnerability, vascular, functional, structural and molecular/genetic factors may be considered.

Adult↗