1,023 research outputs found
Cystic endosalpingiosis presenting as chronic back pain, a case report
No full textA 48-year old woman presented with chronic back pain. Previous examinations had been inconclusive. Gynaecological examination revealed large cystic masses on the fundus uteri and left adnexa. Laparoscopy and histopathology showed unusually extensive cystic endosalpingiosis covering the serosa-coated uterine surface as well as the adnexa on both sides. After uneventful laparoscopic-assisted vaginal hysterectomy the patient quickly recovered and was relieved of her chronic backache
Experimental results for propagation of diffuse photon-density waves up to 1 GHz in a tissue-like medium containing an absorbing edge
No full textOptical imaging in the near-infrared (NIR) region provides the possibility to detect and determine pathological changes in human tissue without the drawback of ionizing radiation and with little technical and financial effort. Especially in rheumatoid arthritis, imaging by optical tomography to detect early inflammations in joints has the potential to become a supportive tool to common imaging modalities. One way to enhance the resolution and specificity of optical tissue characterization is to use the frequency domain instead of DC intensity measurement. Intensity modulation of a light source leads to propagation of diffuse photon-density waves (PDW) through the tissue. In this study, we report basic experimental results on tissuelike phantoms to determine the optimal parameters for PDW-transillumination of finger joints. We used PDW with modulation frequencies from 100 MHz up to 1 GHz to scan across a tissuelike phantom containing an absorbing plane bounded by an edge. The geometrical extents of the phantoms are similar to human finger joints. We measure the transmitted PDW and show that amplitude and phase behaves at the edge as expected according to theoretical predictions. An increasing modulation frequency leads to increasing slope of the amplitude decay at the edge but decreasing signal-to-noise ratio. Even at 1 GHz, the edge is detectable
Challenging dedifferentiated liposarcoma identified by MDM2-amplification, a report of two cases
No full textBackground Liposarcoma is the most frequent soft tissue sarcoma. Well differentiated liposarcoma may progress into dedifferentiated liposarcoma with pleomorphic histology. A minority additionally features myogenic, osteo- or chondrosarcomatous heterologous differentiation. Genomic amplification of the Mouse double minute 2 homolog (MDM2) locus is characteristic for well differentiated and dedifferentiated liposarcomas. Detection of MDM2 amplification may supplement histopathology and aid to distinguish liposarcoma from other soft tissue neoplasia. Case presentation Here we present two cases of dedifferentiated liposarcoma with challenging presentation. Case 1 features a myogenic component. As the tumour infiltrated the abdominal muscles and showed immunohistochemical expression of myogenic proteins, rhabdomyosarcoma had to be ruled out. Case 2 has an osteosarcomatous component resembling extraosseous osteosarcoma. The MDM2 status was determined in both cases and helped making the correct diagnosis. Overexpression of MDM2 and co-overexpression of Cyclin-dependent kinase 4 is demonstrated by immunohistochemistry. The underlying MDM2 amplification is shown by fluorescence in situ hybridisation. Since low grade osteosarcoma may also harbour MDM2 amplification it is emphasised that the amplification has to be present in the lipomatous parts of the tumour to distinguish liposarcoma from extraosseous osteosarcoma. Conclusions The two cases exemplify challenges in the diagnoses of dedifferentiated liposarcoma. Liposarcoma often has pleomorphic histology and additionally may feature heterologous components that mimic other soft tissue neoplasms. Amplification of MDM2 is characteristic for well differentiated and dedifferentiated liposarcomas. Determination of the MDM2 status by in situ hybridisation may assist histopathology and help to rule out differential diagnoses
Signal-to-noise analysis for propagation of laser radiation through a tissue-like medium by diffuse photon-density waves
No full textBiomedical optical imaging in the near-infrared (NIR) region provides the possibility to detect and determine pathological and functional changes in human tissue without the drawback of ionizing radiation. Of special promise is the application of this technology for the detection of joint diseases, such as rheumatoid arthritis (RA). It has been shown that optical changes in the synovial fluid and the vasculature surrounding the joints can be detected with optical methods. Applying optical tomographic methods one should be able to localize and quantify these changes for detection of the onset of RA. The first studies have been limited to continuous wave imaging. However, it is well known that enhanced resolution and better separation between absorption and scattering properties of tissue can be achieved using intensity modulated light sources. Intensity modulation of laser light in the MHz region leads to propagation of so-called diffuse photon density waves (PDW) through the tissue In this study we report on basic experimental results to determine performance and sensitivity of PDW-transillumination of tissue like phantoms. We used a vector network analyzer to generate and analyze intensity modulation from 100 MHz up to 1 GHz via a diode laser and an avalanche photo diode. Scans were performed across phantoms containing a layer with different absorbing and scattering properties bounded by an edge. The thickness of the phantoms was chosen similar to human fingers to gain information for optimization of tomographic imaging of finger joints. We experimentally determined the signal-to-noise ratio (SNR) of the system and compared the results to theoretical predictions. Noise and SNR of amplitude and phase depend on frequency of modulation. While the amplitude SNR decreases with frequency, phase SNR increases to assume a maximum value. We found that the inserted layer can be better characterized using phase information, which becomes more valuable as the source modulation frequency is increased. On the other hand, the sensitivity to perturbations is highest in the amplitude data obtained at lower frequencies. Thus, for tomographic imaging, optimal modulation frequencies should be found depending on the tissue type and nature of tissue inhomogeneities
Computer-aided interpretation approach for optical tomographic images
No full textA computer-aided interpretation approach is proposed to detect rheumatic arthritis (RA) in human finger joints using optical tomographic images. The image interpretation method employs a classification algorithm that makes use of a so-called self-organizing mapping scheme to classify fingers as either affected or unaffected by RA. Unlike in previous studies, this allows for combining multiple image features, such as minimum and maximum values of the absorption coefficient for identifying affected and not affected joints. Classification performances obtained by the proposed method were evaluated in terms of sensitivity, specificity, Youden index, and mutual information. Different methods (i.e., clinical diagnostics, ultrasound imaging, magnet resonance imaging, and inspection of optical tomographic images), were used to produce ground truth benchmarks to determine the performance of image interpretations. Using data from 100 finger joints, findings suggest that some parameter combinations lead to higher sensitivities, while others to higher specificities when compared to single parameter classifications employed in previous studies. Maximum performances are reached when combining the minimum/maximum ratio of the absorption coefficient and image variance. In this case, sensitivities and specificities over 0.9 can be achieved. These values are much higher than values obtained when only single parameter classifications were used, where sensitivities and specificities remained well below 0.8. (C) 2010 Society of Photo-Optical Instrumentation Engineers, [DOI: 10.1117/1.3516705
Sagittal laser optical tomography for imaging of rheumatoid finger joints
No full textWe present a novel optical tomographic imaging system that was designed to determine two-dimensional spatial distribution of optical properties in a sagittal plane through finger joints. The system incorporates a single laser diode and a single silicon photodetector into a scanning device that records spatially resolved light intensities as they are transmitted through a finger. These data are input to a model-based iterative image reconstruction (MOBIIR) scheme, which uses the equation of radiative transfer (ERT) as a forward model for light propagation through tissue. We have used this system to obtain tomographic images of six proximal interphalangeal finger joints from two patients with rheumatoid arthritis. The optical images were compared to clinical symptoms and ultrasound images.NIAMS NIH HHS [R01 AR46255
Light scattering study of rheumatoid arthritis
No full textThe distribution of light scattered by finger joints is studied in the near-IR region. It is shown that variations in the optical parameters of the tissue (scattering coefficient mus, absorption coefficient mua, and anisotropy factor g) depend on the presence of the rheumatoid arthritis (RA). At the first stage, the distribution of scattered light was measured in diaphanoscopic experiments. The convolution of a Gaussian error function with the scattering phase function proved to be a good approximation of the data obtained. Then, a new method was developed for the reconstruction of distribution of optical parameters in the finger cross section. Model tests of the quality of this reconstruction method show good results
Short laws for finite groups and residual finiteness growth
No full text We prove that for every n ∈ N n \in \mathbb {N} and δ > 0 \delta >0 there exists a word w n ∈ F 2 w_n \in F_2 of length O ( n 2 / 3 log ( n ) 3 + δ ) O(n^{2/3} \log (n)^{3+\delta }) which is a law for every finite group of order at most n n . This improves upon the main result of Andreas Thom [Israel J. Math. 219 (2017), pp. 469–478] by the second named author. As an application we prove a new lower bound on the residual finiteness growth of non-abelian free groups. </p
Comparison of sagittal laser optical tomography with ultrasound and clinical examination for diagnosis of synovitis in proximal interphalangeal joints
No full textInterlaboratory concordance of PD ‐L1 immunohistochemistry for non‐small‐cell lung cancer
No full textAims Programmed death ligand 1 ( PD ‐L1) immunohistochemistry has become a mandatory diagnostic test in the treatment of lung cancer. Several research initiatives have started to harmonise the five PD ‐L1 immunohistochemistry assays that have been used in clinical trials. Here, we report data on interlaboratory and interassay concordance for commercial assays (‘assays’) and laboratory‐developed tests ( LDT s) at 10 German testing sites. Methods and results To assess interlaboratory concordance, a tissue microarray containing 21 pulmonary carcinoma specimens was centrally prepared. Pre‐cut sections were stained at 10 sites by the use of assays 28‐8, 22C3, SP 263, and SP 142, as well as 11 LDT s. Assay performance was evaluated with a second tissue microarray containing 11 cell lines with defined PD ‐L1 expression. Quality control was centrally performed by manual and digital analyses. The assays yielded reproducible IHC staining patterns at all sites. In agreement with previous studies, 22C3, 28‐8 and SP 263 showed similar staining patterns, whereas SP 142 was distinct. Among the LDT s, six of 11 protocols showed staining patterns similar to those of assays 22C3 and 28‐8. Interlaboratory concordance of tumour cell scoring by use of a six‐step system was moderate (Light's κ = 0.43–0.69), whereas the clinically approved cut‐offs of ≥1% and ≥50% showed substantial concordance (κ = 0.73–0.89). Immune cell scoring by the use of SP 142 yielded moderate concordance (κ = 0.42). Conclusions The data confirm the previously described staining patterns of the assays, and show that they can be reproducibly employed at different sites. LDT s with staining results similar to those of the assays are implementable, but have to be carefully validated
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