Crucial Diagnostic Information Research Articles

Anterior-segment imaging for assessment of glaucoma

This article summarizes the physics, technology and clinical application of ultrasound biomicroscopy (UBM) and optical coherence tomography (OCT) for assessment of the anterior segment in glaucoma. UBM systems use frequencies ranging from approximately 35 to 80 MHz, as compared with typical 10-MHz systems used for general-purpose ophthalmic imaging. OCT systems use low-coherence, near-infrared light to provide detailed images of anterior segment structures at resolutions exceeding that of UBM. Both technologies allow visualization of the iridocorneal angle and, thus, can contribute to the diagnosis and management of glaucoma. OCT systems are advantageous, being noncontact proceedures and providing finer resolution than UBM, but UBM systems are superior for the visualization of retroiridal structures, including the ciliary body, posterior chamber and zonules, which can provide crucial diagnostic information for the assessment of glaucoma.

The Human Protein Atlas—a tool for pathology

Tissue-based diagnostics and research is incessantly evolving with the development of new molecular tools. It has long been realized that immunohistochemistry can add an important new level of information on top of morphology and that protein expression patterns in a cancer may yield crucial diagnostic and prognostic information. We have generated an immunohistochemistry-based map of protein expression profiles in normal tissues, cancer and cell lines. For each antibody, altogether 708 spots of tissues and cells are analysed and the resulting images and data are presented as freely available in the Human Protein Atlas (www.proteinatlas.org). The new version 4 of the atlas, including more than 5 million images of immunohistochemically stained tissues and cells, is based on 6122 antibodies, representing 5011 human proteins encoded by approximately 25% of the human genome. The gene-centric database includes a putative classification of proteins in various protein classes, both functional classes, such as kinases or transcription factors and project-related classes, such as candidate genes for cancer or cardiovascular diseases. For each of the internally generated antibodies, the exact antigen sequence is presented, together with a visualization of application-specific validation data, including a protein array assay, western blot analysis, immunohistochemistry and, in most cases, immunofluorescent-based confocal microscopy. The updated version also includes new search algorithms to allow complex queries regarding expression profiles, protein classes and chromosome location. Thus, the presented Human Protein Atlas provides a resource for pathology-based biomedical research, including protein science and biomarker discovery.

Phase-inversion tissue harmonic imaging compared to fundamental B-mode ultrasound in the evaluation of the pathology of large and small bowel

Our purpose was to compare phase-inversion harmonic imaging (PIHI) with conventional B-mode ultrasound (US) regarding image quality in the evaluation of bowel pathology. Forty-one patients prospectively underwent intestinal ultrasound scans with US and PIHI in randomly chosen order. Crucial technical parameters were standardized. Bowel morphology as well as perienteric pathology and complications were documented. In 24 cases, the ultrasound results were compared to those of other imaging modalities. Three radiologists evaluated (1) overall image quality, (2) lesion conspicuity and diagnostic confidence, and (3) detection of free fluid on hardcopy films. The ratings for image quality were compared using the two-sample paired t test for means and Bowker's test for symmetry (p=0.05). Compared to US, PIHI provided significantly better overall image quality, lesion conspicuity and diagnostic confidence, as well as better detection of free fluid (p< 0.05). Bowel wall pathology, detected by both modalities, showed good correlation to additional imaging modalities. In 12 patients (29.3%), a gain of crucial diagnostic information was observed with PIHI when compared to US. PIHI significantly enhances sonography of the intestine by offering better overall image quality, better visualization of bowel pathology and associated changes. Additionally, PIHI adds crucial diagnostic information in several patients.

Characterization of focal liver lesions with contrast-enhanced ultrasound.

The development of second-generation contrast agents and newer specific contrast imaging methods has improved the accuracy of US in the characterization of FLLs using a combination of vascular and parenchymal approaches. CEUS provides crucial diagnostic information about the pattern enhancement of the most frequent FLLs, and can be usefully employed as a first-line technique when a FLL is detected using US.

Imaging of liver metastases with contrast-specific low-MI real-time ultrasound and SonoVue.

Until recently, US was the preferred screening method for focal liver lesion disease because of the inherent advantages; however, it suffered a relatively poor sensitivity and specificity rate compared with other imaging techniques, such as CT and MRI, and further imaging was often required for a definitive diagnosis. Since the advent of US contrast agents and new contrast-specific US techniques, US of the liver has improved dramatically. Detection of metastases is markedly improved as is lesion characterisation. The detection of liver metastases using CEUS is similar to spiral CT. The ability of contrast US to characterise focal liver lesions is superior to that of CT and at least equivalent to that of MRI. On the other hand, some limitations of US remain, such as its operator dependence or the limited access to certain parts of the liver especially in obese patients and/or fatty livers. CEUS is a young field in which unexpected progress has been made in the last few years and is now at a stage where it is ready for routine clinical use. It adds a new dimension to liver US. We would like to encourage all radiologists and sonographers to start using it, since it provides crucial diagnostic information that is completely occult in conventional sonography, allowing it to rival CT and MRI.

Introduction to functional pelvic floor imaging

Pelvic floor problems leading to incontinence, constipation and prolapse are common and underappreciated.Radiological imaging provides crucial diagnostic information and helps guide treatment.The pelvic floor should be seen as a single functional unit.

Transesophageal Echocardiography in the Critical Care Unit

Transesopageal echocardiography is highly sensitve for evaluation of cardiac structure and hemodYnamics of blood flow through the hea.rt In the critical care setting, it often is used as a basis for additional evaluation once transthoracic methods have been inconclusive. Tis retrospectiv study was designed to report the management impact of transesophagejal echocardiography in the cntically ill patient population. Documentation for X each patient included a clinical diagsis at admission, along with;the results of the transesophageal echocariography and its impact on:patient treatment. Te imxpact of transesopagal echocariography in relation to patient treatment was baseon therapy or surgical intervention changes. The most common concerns requiring additional analysis of cardiac structures Weto rule out endocarditis (23%), evaluate hemodyvnamic instability (22.%), and to diagnose the source of embolism (21%). Of these 92 patients, 43 were postoperative evaluations. Tiansesophageal echocardioaphy was feasible in all attempts and the results prompted 37 (40%) of the patients to have treatment changes as a direct result of the examination. These findings suggest that transesophageal ehocahrdiography proides crucial diagnostic information impottant for crtical care management decisions in a safe and efctiwe manner.

Image sequence coding by adaptive vector quantization with variable block size

One problem with vector quantization for image sequence coding is poor reproduction of edges. This problem is particularly serious in applications to angiographic image sequences, where the edge information is often the crucial diagnostic information. A novel method proposed in this paper is adaptive vector quantization with variable block size. A large block size is desirable as it requires a lower bit rate; however, it can result in poor edge reproduction. On other hand, a smaller block size requires a higher bit rate but edges are better reproduced. An activity index is used to separate the blocks into two classes: active and nonactive. The nonactive blocks are coded by a primary codebook with a vector dimensionality of 16. The active blocks are further divided into smaller blocks of size 2 × 2 and coded by a secondary codebook. We show that it is possible to derive one codebook that applies to both vector dimensions. The temporal redundancies of the image sequence are exploited by using a modified replenishment technique: only the vector labels which change from frame to frame are transmitted. Pictorial results show that the edge features are well preserved upon reconstruction at bit rates about 0.7 bit/pixel.

Computed tomography in Crohn disease.

Twelve patients with Crohn disease were studied by computed tomography. Characteristic findings of small intestinal involvement include symmetrical bowel wall thickening, a "double halo" appearance on cross section of the diseased bowel segment, and an associated mesenteric fat mass. Computed tomography provided crucial diagnostic information in the management of some of the intestinal and extraintestinal complications of the disease.

A Study of “Feature-Gram” Profiles for Three Different Hearing Impaired Language Groups

The responses of 36 hard-of-hearing subjects from three different language groups to logatomes were analysed by an information transmission statistic involving seven distinctive features of consonant phonemes. The percent-information transmission values associated with the seven distinctive features for each of the three language groups were plotted and ranked from the most weighted to the least weighted features. These plottings have been called “Feature-Grams” since they contain crucial diagnostic information regarding the hearing impaired subjects' phonemic repertoires. A comparison of the “Feature-Grams” and the pure tone audiograms show the importance of the former in the realistic assessment of the patients' hearing for speech sounds.