Evaluation of augmented reality training for a navigation device used for CT-guided needle placement.

PURPOSE: Numerous navigation devices for percutaneous, CT-guided interventions exist and are, due to their advantages, increasingly integrated into the clinical workflow. However, effective training methods to ensure safe usage are still lacking. This study compares the potential of an augmented reality (AR) training application with conventional instructions for the Cube Navigation System (CNS), hypothesizing enhanced training with AR, leading to safer clinical usage. METHODS: An AR-tablet app was developed to train users puncturing with CNS. In a study, 34 medical students were divided into two groups: One trained with the AR-app, while the other used conventional instructions. After training, each participant executed 6 punctures on a phantom (204 in total) following a standardized protocol to identify and measure two potential CNS procedural user errors: (1) missing the coordinates specified and (2) altering the needle trajectory during puncture. Training performance based on train time and occurrence of procedural errors, as well as scores of User Experience Questionnaire (UEQ) for both groups, was compared. RESULTS: Training duration was similar between the groups. However, the AR-trained participants showed a 55.1% reduced frequency of the first procedural error (p > 0.05) and a 35.1% reduced extent of the second procedural error (p < 0.01) compared to the conventionally trained participants. UEQ scores favored the AR-training in five of six categories (p < 0.05). CONCLUSION: The AR-app enhanced training performance and user experience over traditional methods. This suggests the potential of AR-training for navigation devices like the CNS, potentially increasing their safety, ultimately improving outcomes in percutaneous needle placements.

Percutaneous cervical vertebroplasty in a multifunctional image-guided therapy suite: hybrid lateral approach to C1 and C4 under CT and fluoroscopic guidance.

A 76-year-old patient suffering from two painful osteolytic metastases in C1 and C4 underwent percutaneous vertebroplasty by a hybrid technique in a multi-functional image-guided therapy suite (MIGTS). Two trocars were first placed into the respective bodies of C1 and C4 under fluoroscopic computed tomography guidance using a lateral approach. Thereafter, the patient was transferred on a moving table to the digital subtraction angiography unit in the same room for implant injection. Good pain relief was achieved by this minimally invasive procedure without complications. A hybrid approach for vertebroplasty in a MIGTS appears to be safe and feasible and might be indicated in selected cases for difficult accessible lesions.

Radiation dose in vertebroplasty.

We wished to measure the absorbed radiation dose during fluoroscopically controlled vertebroplasty and to assess the possibility of deterministic radiation effects to the operator. The dose was measured in 11 consecutive procedures using thermoluminescent ring dosimeters on the hand of the operator and electronic dosimeters inside and outside of the operator's lead apron. We found doses of 0.022-3.256 mGy outside and 0.01-0.47 mGy inside the lead apron. Doses on the hand were higher, 0.5-8.5 mGy. This preliminary study indicates greater exposure to the operator's hands than expected from traditional apron measurements.

[Diagnosis of cerebrospinal fluid leakage at the base of the skull]. / Diagnostik der Liquorrhoe bei Schädelbasisläsionen.

There are still several problems surrounding the diagnosis of cerebrospinal fluid leak. Currently the method of choice for cerebrospinal fluid detection is qualitative determination of beta-2-transferrin. Faster and more efficient methods (beta-trace) are under clinical investigation. The major problem is localisation of the site of leakage. Combination of several radiological methods increases the rate of correct diagnosis. In surgery the use of intrathecal sodium-fluorescein improves visualisation of the site of leakage and thus increases the chances of secure and stable closure of the cerebrospinal fluid fistula.

Cortical reorganization after acute unilateral hearing loss traced by fMRI.

Unilateral acoustic stimulation produces a functional MRI (fMRI)-blood-oxygenation-level-dependent (BOLD) response mainly in the contralateral auditory cortex. In unilateral deaf patients, the BOLD response is bilateral. We studied a subject with sudden hearing loss after cochlear nerve resection before and repeatedly after surgery. During normal bilateral hearing, contralateral cortical BOLD responses were found. Progressing compensatory reorganization with bilateral representation of unilateral stimulation was detected over a period of approximately 1 year.

Cerebral veins: comparative study of CT venography with intraarterial digital subtraction angiography.

BACKGROUND AND PURPOSE: Our objective was to compare the reliability of CT venography with intraarterial digital subtraction angiography (DSA) in imaging cerebral venous anatomy and pathology. METHODS: In 25 consecutive patients, 426 venous structures were determined as present, partially present, or absent by three observers evaluating CT multiplanar reformatted (MPR) and maximum intensity projection (MIP) images. These results were compared with the results from intraarterial DSA and, in a second step, with the results of an intraobserver consensus. In addition, pathologic conditions were described. RESULTS: Using DSA as the standard of reference, MPR images had an overall sensitivity of 95% (specificity, 19%) and MIP images a sensitivity of 80% (specificity, 44%) in depicting the cerebral venous anatomy. On the basis of an intraobserver consensus including DSA, MPR, and MIP images (415 vessels present), the sensitivity/specificity was 95%/91% for MPR, 90%/100% for DSA, and 79%/91% for MIP images. MPR images were superior to DSA images in showing the cavernous sinus, the inferior sagittal sinus, and the basal vein of Rosenthal. Venous occlusive diseases were correctly recognized on both MPR and MIP images. Only DSA images provided reliable information of invasion of a sinus by an adjacent meningioma. CONCLUSION: CT venography proved to be a reliable method to depict the cerebral venous structures. MPR images were superior to MIP images.

Ruptured intracranial dermoid cyst.

Intradural dermoids are rare congenital tumors representing approximately 0.05% of all intracranial lesions. These benign tumors have a typical appearance on CT and MR due to their lipid components. The complication caused by rupture are the spillage of the fatty material into the cerebrospinal fluid. We report a case of a ruptured dermoid cyst showing fat/fluid levels in both side ventricles and fatty material in the subarachnoid space on CT and MR-imaging and the follow-up over four years after incomplete resection of the tumor.

Characterization of seed storage proteins in Populus and their homology with Populus vegetative storage proteins.

We investigated the synthesis and accumulation of vegetative storage proteins (VSPs) in poplar plantlets and the homology between poplar seed storage proteins (SSPs) and VSPs. One-dimensional SDS polyacrylamide gel electrophoresis confirmed that both seed and vegetative storage proteins contained two predominant polypeptides of MW 32 and 36 kDa, but the subunit composition of the polypeptides differed. The 32- and 36-kDa polypeptides were highly abundant in basal leaves, stems, and roots of poplar plantlets. The 36-kDa subunit was synthesized in all plantlet tissues examined, but the 32-kDa subunit was not, suggesting that the 36-kDa polypeptide is a precursor of the 32-kDa polypeptide. The 36- and 32-kDa polypeptides of both SSPs and VSPs were glycosylated and both were found to be albumins. In addition, both polypeptides cross-reacted with a VSP antibody. Protein fingerprint patterns generated with two different proteolytic enzymes were identical for the 36-kDa polypeptide isolated from seeds or from stem tissue. Our study provides evidence that poplar SSPs and VSPs exhibit homology, and that expression is neither tissue-specific nor regulated solely by photoperiod.

Anatomic evaluation of the circle of Willis: MR angiography versus intraarterial digital subtraction angiography.

PURPOSE: To evaluate the reliability of source images and maximum intensity projection images of MR angiography in showing the arterial segments of the circle of Willis. METHODS: In 62 patients, 526 arterial segments of the circle of Willis were determined to be present, partially present, or absent by blinded observers evaluating MR angiographic source images and maximum intensity projection images. Vessel diameter was measured on source images. These results were then compared with the results from intraarterial digital subtraction angiography. RESULTS: MR angiographic maximum intensity projection images had a sensitivity of 87% and a specificity of 88% and MR angiographic source images had a sensitivity of 89% and a specificity of 63% in depicting the presence of a vessel segment. The positive predictive value of an arterial segment with a diameter of at least 1 mm was 99%. CONCLUSION: MR angiography is a sensitive technique for detecting the anatomy of the circle of Willis. Maximum intensity projection images are more specific than source images. An arterial segment with a diameter of at least 1 mm on the source image is almost always present and patent.

[Pseudotumor calcinosis in renal failure]. / Pseudotumoröse Kalzinose bei Niereninsuffizienz.

Tumoral Calcinosis is a rare clinical entity characterized by the presence of calcified, periarticular masses, as seen on radiographs. A severe case in a patient with chronic renal failure is presented and the complex etiology of this disease is discussed.

Dual EBNA1 promoter usage by Epstein-Barr virus in human B-cell lines expressing unique intermediate cellular phenotypes.

The use of different viral promoters for the expression of the EBNA1 gene product appears to be a critical step in the regulation of Epstein-Barr virus latent gene expression and may reflect the extent of differentiation of B-cell hosts. Low-passage Burkitt lymphoma cell lines resemble immature B cells in that they express CD10 (CALLA) and do not express B-cell activation antigens. In these cells, transcription from a promoter located in the BamHI F fragment of the viral genome results in the exclusive expression of EBNA1, referred to as the latency I pattern of viral gene expression. In contrast, high-passage Burkitt lymphoma cells and lymphoblastoid cell lines resemble activated B cells in that they do not express CD10 but do express activation antigens such as CD23. In these cells, the use of two promoters located in the BamHI W and C fragments of the viral genome leads to the expression of all six EBNA gene products (latency III). We have found that four human B-cell lines, DB, LBW2, LBW14, and Josh 7, stably express a pattern of B-cell differentiation antigens intermediate between those found in latency I and latency III cell lines and characterized by the coexpression of CD10 and CD23. The pattern of EBNA1 promoter usage in these cell lines was examined to determine whether their intermediate cellular phenotype was reflected in their patterns of viral gene expression. DB, LBW2, and LBW14 utilize both the BamHI F promoter region and BamHI W promoter region to transcribe the EBNA1 gene. This stable pattern of mixed promoter usage for the expression of the EBNA gene products in B cells has not previously been described. In addition, these three B-cell lines expressed lower levels of the viral latent gene product EBNA2 than those typically observed in latency III cells. The lower levels of activation of viral and cellular promoters known to be regulated by EBNA2 also correlated with the reduced levels of EBNA2 expression in these cells. These included the viral LMP1 and LMP2A promoters and the cellular CD23B promoter. The fourth B-cell line, Josh 7, expressed EBNA1 mRNAs derived from both the BamHI W promoter and BamHI C promoter, similar to latency III cells. The intermediate cellular phenotype in Josh 7 cells appeared to be due, in part, to a deficiency in the expression of viral LMP1.(ABSTRACT TRUNCATED AT 400 WORDS)

Conserved patterns of somatic mutation and secondary VH gene rearrangement create aberrant Ig-encoding genes in Epstein-Barr virus-transformed and normal human B lymphocytes.

Expression of N-terminal-truncated Ig heavy chains without normal light chain expression has been shown to occur in human B cell tumor lines, and to be due to diverse types of structural alteration within the expressed Ig heavy and light chain genes. Due to the tumor cell origin of these lines, generation of aberrant Ig-encoding genes may only occur after malignant transformation, reflecting the release of the tumor B cell from the need to express functional Ig for continued clonal proliferation. The genetic basis for expression of VH-truncated mu chains without light chains in several Epstein-Barr virus (EBV)-transformed human B cell lines was investigated with the aim that this information would lead to detection of similarly aberrant Ig genes in normal human B lymphocytes. Analysis of the productive mu genes in three truncated mu-only human B cell lines showed a consistent structural change where a secondary VH-VHDJH gene rearrangement had occurred. The site of VH-VH joining was suggestive of a V(D)J recombinase-mediated event. A consistent pattern of mutation was also observed in the normal-sized, but non-functional kappa light chain transcripts, making them incapable of coding for a functional kappa chain. Using genomic DNA from peripheral blood lymphocytes of a donor whose B cells were originally used to make one of the truncated mu-only EBV B cell lines, a similarly mutated V kappa gene was detected and a similar composite VH-VH gene was cloned. The lack of such aberrant VH and V kappa genes in non-lymphoid cells of this individual showed that the structural abnormalities in the expressed Ig genes arose somatically during development of that B cell clone. The presence of these altered Ig heavy and light chain genes in the genomic DNA of untransformed lymphocytes also shows that generation of such variant B cell clones can be a pre-neoplastic event and occurs by genetic mechanisms active during normal B cell development.

Hyperthyroid adult rat cardiomyocytes. I. Nucleotide content, beta- and alpha-adrenoreceptors, and cAMP production.

Ventricular myocytes isolated from the hypertrophied hearts of thyrotoxic adult rats have an increase in mean protein content per myocyte (6.3 +/- 0.2 vs. 4.4 +/- 0.2 ng) compared with euthyroid cells. Viability and adenine nucleotide profiles are similar in both populations, but NAD content of the hyperthyroid myocytes is depressed (4.9 +/- 0.2 vs. 5.5 +/- 0.2 nmol/mg for controls) and UTP is higher (1.2 +/- 0.09 vs. 0.9 +/- 0.04 nmol/mg). Binding of (-)-[125I]iodocyanopindolol to intact hyperthyroid myocytes is increased by 42% compared with controls, with no change in the dissociation constant (Kd). This elevation in beta-receptor number is correlated to enhanced beta-agonist-induced adenosine 3',5'-cyclic monophosphate (cAMP) production. The half-maximal effective concentration (EC50) for the euthyroid isoproterenol dose-response curve is 2.14 x 10(-7) M but is decreased to 2.51 x 10(-8) M in hyperthyroid cardiac cells. Basal adenylate cyclase activity is apparently not affected by thyroid hormones, since basal cAMP levels for both groups are identical (5 pmol/mg) and both rise roughly twofold in the presence of a phosphodiesterase inhibitor. Forskolin-induced cAMP production and cAMP-specific phosphodiesterase activity are similar as well. In contrast to beta-adrenergic response, there are no significant differences in alpha 1-antagonist [3H]prazosin binding parameters between hyperthyroid and euthyroid cardiomyocytes.

[Diagnostic and therapeutic aspects of early (superficial) gastric carcinoma: a retrospective analysis of 60 cases (author's transl)]. / Diagnostische und therapeutische Aspekte des Magenfrühkarzinoms. Eine retrospektive Analyse von 60 Magenfrühkarzinomen.

Among 947 patients operated on for gastric carcinoma between 1961 and 1976 there were 60 with early (superficial) gastric carcinoma. All but two patients consulted their doctor for diverse complaints. In one third of them treatment was delayed for a year or longer. In 26 of the 64 cancer foci it was limited to the mucosa. The correct diagnosis was made radiologically in 60%, gastroscopically in 70%. Selective endoscopic biopsy increased accuracy to 90%. The remaining false-negative findings occurred in the ulcerative form, which was the most frequent one. Improved radiological techniques (double-contrast) and obligatory gastroscopy with biopsy increased the relative proportion of early (superficial) carcinoma from under 4% in 1961 to 15%. The diagnosis of this type of carcinoma can be made only by careful histological study of the surgical specimens. Here as elsewhere in the surgery of carcinoma, multicentricity (in 5%) and possible lymph node metastases (10-20%) must be taken consideration in the surgical management.