Digital ultraviolet therapy: a novel therapeutic approach for the targeted treatment of psoriasis vulgaris.

BACKGROUND: 8-Methoxypsoralen-UVA (PUVA) and narrowband ultraviolet B (NB-UVB) are well-established treatments for chronic plaque-type psoriasis vulgaris. However, long-term risks of PUVA therapy include premature skin ageing and squamous cell carcinoma. OBJECTIVES: To develop a device for targeted UV therapy of psoriatic plaques with protection of the healthy adjacent skin to reduce the risk for premature skin ageing and squamous cell carcinoma. METHODS: In total 28 patients with exacerbated psoriasis vulgaris were treated with the digital phototherapy device skintrek(®) [cream PUVA (n = 8), bath PUVA (n = 11) and UVB (n = 9)] or with conventional bath PUVA (n = 9) or NB-UVB (n = 4). RESULTS: The local Psoriasis Area and Severity Index (PASI) score was significantly reduced from a mean of 6·25 at baseline to 2·75 at the end of therapy in the skintrek cream PUVA group, from 6·4 to 3·0 in the skintrek bath PUVA group and from 5·5 to 2·0 in the skintrek UVB group. Treatment with skintrek cream PUVA reduced the mean local PASI by 54%, while skintrek bath PUVA did so by 51% and skintrek UVB by 63%. Targeted skintrek PUVA and skintrek UVB of inflamed psoriatic skin avoided skin pigmentation and were not inferior to conventional bath PUVA and NB-UVB therapy regimens. CONCLUSIONS: Targeted UV therapy of psoriatic plaques with the digital phototherapy device skintrek is as effective as conventional cream and bath PUVA, as well as NB-UVB, while simultaneously sparing the healthy adjacent skin. It therefore potentially reduces the carcinogenic risk, reduces premature skin ageing and avoids tanning of healthy surrounding skin.

The Morel stereotactic atlas of the human thalamus: atlas-to-MR registration of internally consistent canonical model.

In 1997, Morel, Magnin, and Jeanmonod presented a microscopic stereotactic atlas of the human thalamus. Parcellations of thalamic nuclei did not only use cyto- and myeloarchitectonic criteria, but were additionally corroborated by staining for calcium-binding proteins, which bears functional significance. The atlas complies with the Anglosaxon nomenclature elaborated by Jones and the data were sampled in three orthogonal planes in the AC-PC reference space. We report on the generation of three-dimensional digital models of the thalamus based on the three sets of sections (sagittal, horizontal, and frontal). Spatial differences between the three anatomical specimens were evaluated using the centers of gravity of 13 selected nuclei as landmarks. Subsequent linear regression analysis yielded equations, which were used to normalize the frontal and horizontal digital models to the sagittal one. The outcome is an internally consistent Canonical Model of Morel's atlas, which minimizes the linear component of the variability between the three sectioned anatomical specimens. In addition, we demonstrate the feasibility of the atlas-to-MRI registration in conjunction with on-line visualization of the trajectory in the digital models.

One atlas - three anatomies: relationships of the Schaltenbrand and Wahren microscopic data.

The stereotaxic atlas of Schaltenbrand and Wahren is widely used for orientation in functional neurosurgery of the human diencephalon. As the sagittal, frontal, and horizontal microscopic series were gathered from three different cerebral hemispheres, loci with the same ACPC (anterior commissure-posterior commissure) coordinates are not exactly anatomically corresponding. We compared the 3-D position of 21 anatomical structures in the three series based on their digitally interpolated solid volume representations. Regression analysis of the centres of gravity revealed strong linear correlations between series (0.944< or = Pearson's r< or = 0.976, alpha<0. 0001). Thus calculation of anatomically corresponding sites based on the regression equations seems justified. Volumetry revealed that the sagittally sectioned thalamus is approximately 10% larger than the frontally and 40% larger than the horizontally sectioned thalamus. So as to match it to the sagittal series, the frontal series has to be widened in lateral direction by 19%, in anteroposterior and dorsobasal (vertical) direction it has to be compressed by 5 and 9%, respectively. In contrast, the distance of structures from the midline in the horizontal and sagittal series is very similar. The horizontal series is, however, 25% smaller than the sagittal one in anteroposterior and 17% in vertical direction. On average, thalamic nuclei in the right hemisphere of brain LXXVIII (horizontal microscopic series) were located 2 mm more anterior as compared with the left side (sagittal series), which fact may be explained by difference in size and/or asymmetry. Spatial overlap between corresponding thalamic nuclei from the three series amounted to only 0-28% when superimposed in the ACPC reference space. Linear transformation towards an average led to significant increase (0-37%, p<0.001) of the overlap and ameliorated the quality of the fit of thalamic borders. Limited increase of the overlap is in part due to pronounced differences in the size of thalamic nuclei between the series.

Verification of the Schaltenbrand and Wahren stereotactic atlas.

The Schaltenbrand and Wahren stereotactic atlas was critically re-examined focusing on the technical quality and the consistency of the horizontal, sagittal and frontal microscopic cut series. From each series, both an isotropic contour and a solid volume model represented by a 256 matrix with an edge length of 6.4 cm were created using 3D-interpolation. Reslicing of the solid volumes in corresponding orthogonal planes enabled thorough direct comparison of the three series. In a 3D-navigation system prototype, the contour models can be matched to MRI and CT series. Different procedures for rigid matching including landmark matching were implemented. As regards the verification criteria, the frontal Schaltenbrand and Wahren series yielded the most comprehensible results whereas in the horizontal and sagittal series artifacts appear more pronounced.