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At least 919 records · Page 51Linked to original sources
PubMed1988

Quantitative evaluation of real-time ultrasound features of the breast.

Semi-quantitative diagnostic features were extracted by a visual analysis of the echographic images of selected cases of breast disease and the results stored in a computer database. The long term aim is to create an environment suitable for the use of multivariate statistical methods systematically to evaluate ultrasound interpretive criteria and diagnostic performance in relation to factors such as scanning instrumentation and other diagnostic techniques. Eventually it is hoped that it will be possible to generate a system for computer assisted diagnosis and training. The results of this pilot study serve to demonstrate the feasibility of the approach and a univariate analysis is used to provide a preliminary ranking of diagnostic features. Features found to be particularly valuable for distinguishing benign from malignant solid lesions were the regularity and definition of the edge of the tumour, the mobility of the tumour and measures of echo heterogeneity within and posterior to the tumour mass.

Breast↗
PubMed1978

[The transmediastinal pleurotomy (author's transl)].

A new surgical method is presented, the transmediastinal pleurotomy. With this technique it is possible to explore the opposite lung from a standard thoracotomy and to perform diagnostic or therapeutic resections in suitable cases. So far we have performed 20 transmediastinal pleurotomies without any complications.

Humans↗
PubMedDate not supplied

The nurse endoscopist: reality or fiction?

In this article, the author describes a study conducted to determine whether advanced practice registered nurses (APRNs) should perform endoscopic procedures, such as colonoscopy and esophagogastroduodenoscopy. Questionnaires were mailed to APRNs belonging to the Society of Gastroenterology Nurses and Associates. Questionnaire items pertained to demographics, current activities, interest in performing GI endoscopic procedures, and barriers to performing GI endoscopic procedures. Over 70% of respondents approved of nurses performing diagnostic endoscopic procedures, yet 80.6% did not think that nurses should perform therapeutic endoscopic procedures. Training opportunities were limited. The barriers to performing endoscopic procedures included liability, third-party reimbursement, lack of physician support, lack of policies, and lack of education. APRNs should develop policies and establish acceptable training guidelines and competency rates in performing GI endoscopic procedures.

Clinical Competence↗
PubMed1977

The construction and use of diagnostic standards for radiographic caries incidence scores.

The aim was to construct and illustrate the use of diagnostic standards for recording of DFS incidence. Separate standards are presented for ranking of subjects; the mean "intermediate" DFS score per subject, which represented the majority decision of three dentists; and a certainty scale for individual tooth surfaces. The scores recorded for 40 sets of posterior bitewing radiographs of children between 13 and 15 years of age by two fourth year dental students and two dental hygienists were compared with the standards. Spearman's rank correlation coefficient reached the critical level of +0.70 in three of eight instances. Only one mean net DFS increment score differed significantly from the mean standard score (p less than 0.05). The level of agreement with the certainty scale for individual surfaces was low. Focusing attention on recording of DFS incidence gives a more severe test of examiners' diagnostic performance. The construction and use of control charts for monitoring the diagnostic level of examiners is suggested.

Adolescent↗
PubMed2005

Effects of monitor luminance change on observer detection performance.

To confirm that the dimming luminance change in the CRT monitor will have a detrimental effect on diagnostic performance, we performed the four-alternative forced choice experiments on the CRT monitor with the 11 luminance conditions simulating CRT degraded by long-term usage. Six radiologists and one pulmonary physician performed a detection task for 11,000 test areas on 110 test images. The 11 monitor conditions significantly affected the correct detection rates of simulated nodules in the four-alternative forced choice experiments. The gradual deterioration in CRT monitor luminance will have certainly a detrimental effect on detection performance.

Computer Terminals↗
PubMed2004

Computer-aided diagnosis for CT colonography.

CT colonography, or virtual colonoscopy, is a promising alternative screening tool for colon cancer. Computer-aided diagnosis (CAD) for CT colonography has the potential to increase radiologists' diagnostic performance in the detection of polyps and to reduce variability of the diagnostic accuracy among readers. Technical developments have advanced CAD for CT colonography substantially during the last several years. This paper describes the key techniques used for CAD for detection of polyps and masses in CT colonography, the current detection performance, and challenges and the future of CAD.

Colonic Polyps↗
PubMed1976

Results of diagnostic pelviscopy in cases of chronic recurrent pelvic disease.

During the last two years we have performed diagnostic pelviscopy in 90 patients suffering from a syndrome of chronic repeated pelvic disease. In 44 patients extragenital endometriosis was diagnosed as the causing factor. In 15 cases we found wide-spread adhesions in the region of the lower pelvis after preceeding laparotomies. Only in 12 patients pelvic-alterations caused by chronic inflammatory processes of the adnexa with peritubal adhesions were discovered. As these results show extragenital endometriosis represents in far more cases as generally believed the cause of gynecological pains. We want to give special emphasis to the diagnosis and treatment of this disease.

Adult↗
PubMed1992

Impact of hard-copy size on observer performance in digital chest radiography.

To determine the impact of reduced hard-copy size on diagnostic performance of digital radiography, screen-film chest radiographs were compared with isodose digital storage phosphor radiographs in the detection of simulated nodules, fine pulmonary lines, and micronodular opacities superimposed on the chests of 10 healthy volunteers. Digital radiographs were laser-printed in a full-size conventional format and in image lengths of two-thirds, one-half, and five-elevenths of the conventional format. Eighteen thousand observations by eight radiologists were analyzed by use of receiver operating characteristics. The detectability of lines and micronodular opacities decreased with declining image format size. In the detection of micronodular opacities, only the nearly full-size digital images were equivalent to conventional images. In the detection of linear opacities, reduction of image length by one-half or more reduced performance (analysis of variance, P less than .05). Only for the detection of nodules was no major difference found.

Humans↗
PubMed1992

Delay by internists in obtaining diagnostic biopsies in patients with suspected cancer.

OBJECTIVE: To investigate the degree and type of delays in performing diagnostic biopsies in medical patients with suspected malignancy. DESIGN: Retrospective survey of clinical histories of patients referred between January 1985 and March 1989. SETTING: Inner city teaching hospital internal medicine (non-oncologic) services. PATIENTS: Patients with gastrointestinal and lung cancers, adenocarcinoma of unknown primary site, and lymphomas were referred as inpatients by internists. Two hundred fifty-five patients were eligible, and 177 were evaluable. MAIN OUTCOME MEASURES: The number, type, and results of tests done before and after biopsy were analyzed. RESULTS: In 67% of patients the biopsied lesion was detected by the second day of evaluation; however, there was an 8- to 10-day delay before a biopsy was done. This delay was consistent across the four malignancy groups studied. Although logistic and other unavoidable delays occurred in 40% of the cases, in 60% delays could only be attributed to continued, frequently low yield, noninvasive tests. An average of 3.3 tests were made per patient, with only 24% leading to a definitive biopsy. CONCLUSION: Because of the performance of many other tests, a substantial delay exists in proceeding to biopsy during the diagnosis of cancer by internists.

Adenocarcinoma↗
PubMed2005

GEMS: a system for automated cancer diagnosis and biomarker discovery from microarray gene expression data.

The success of treatment of patients with cancer depends on establishing an accurate diagnosis. To this end, we have built a system called GEMS (gene expression model selector) for the automated development and evaluation of high-quality cancer diagnostic models and biomarker discovery from microarray gene expression data. In order to determine and equip the system with the best performing diagnostic methodologies in this domain, we first conducted a comprehensive evaluation of classification algorithms using 11 cancer microarray datasets. In this paper we present a preliminary evaluation of the system with five new datasets. The performance of the models produced automatically by GEMS is comparable or better than the results obtained by human analysts. Additionally, we performed a cross-dataset evaluation of the system. This involved using a dataset to build a diagnostic model and to estimate its future performance, then applying this model and evaluating its performance on a different dataset. We found that models produced by GEMS indeed perform well in independent samples and, furthermore, the cross-validation performance estimates output by the system approximate well the error obtained by the independent validation. GEMS is freely available for download for non-commercial use from http://www.gems-system.org.

Algorithms↗
PubMed1998

Comparison of performances of two commercially available tests, a PCR assay and a ligase chain reaction test, in detection of urogenital Chlamydia trachomatis infection.

The diagnostic performance of a PCR test (Roche Cobas Amplicor CT/NG Test) and that of a ligase chain reaction (LCR) test (Abbott LCx Chlamydia trachomatis assay) were compared by using endocervical and urethral swab specimen culture as a reference test. First-void urine (FVU) and endocervical and urethral swab specimens were collected from 1,015 unselected patients attending a sexually transmitted disease clinic and a clinic for adolescents in Helsinki, Finland. Chlamydia trachomatis was cultured from samples from the endocervix or urethra. PCR was performed with fresh and frozen urine and the culture transport medium. LCR was performed with fresh and frozen urine and LCx swab transport medium. Diagnostic consistency and diagnostic accuracy were statistically tested. The test results were identical for 984 patients (97%). Discrepant results were observed for 31 patients. Overall, LCR and PCR showed excellent kappa coefficients of consistency for both swab and FVU specimens (0.93 and 0.95, respectively). Sixty-one patients (6%) were culture positive. Testing of FVU by LCR or PCR increased the overall positivity rates to 7.0 and 7.7%, respectively. While PCR of FVU detected the greatest number of C. trachomatis infections (sensitivity, 96.1%), for some PCR-positive FVU specimens the results could not be confirmed (specificity, 99.6%). PCR and LCR were more sensitive than culture (sensitivities, 92 and 93% versus 79% for culture) in the diagnosis of genital C. trachomatis infection. In conclusion, both tests can be recommended for use in the clinical laboratory and for the screening of asymptomatic C. trachomatis infections.

Cervix Uteri↗
PubMed2003

Thallium-201-chloride scintigraphy in staging and monitoring radiotherapy response in follicular lymphoma patients.

PURPOSE: To study thallium-201-chloride scintigraphy (201Tl-S) in staging and monitoring response after radiotherapy in follicular lymphoma (FL) patients. PATIENTS AND METHODS: Forty-one consecutive and unselected FL patients were examined by 'Conventional Standard Staging' (CSS) procedures (history and physical examination, ultrasound, CT scans, biopsies and fine needle aspiration cytology) prior to irradiation. Eight standardized potentially affected lymphoma localizations (neck, axilla, mediastinum, spleen, paraaortic, parailiac, femoral and extranodal) per patient were separately studied, resulting in the investigation of 328 localizations. Thirty minutes after the intravenous administration of a tracer dose of 150 MBq thallium-201-chloride total body images were made, immediately followed by single photon emission computed tomography acquisition. All lymphoma localizations were subsequently irradiated. Patients were re-examined after a median of 4 weeks (range 3-6 weeks) by all CSS modalities and 201Tl-S. Diagnostic performance was evaluated both per site and per patient, both in the diagnostic phase of the study as well as in the post-treatment re-evaluation phase. RESULTS: In staging, 201Tl-S was positive in 82 of the 129 initial positive regions by CSS (64%). This percentage increased to 70% when eliminating upper abdominal lymph nodes from the analysis. In 24 patients all lesions were visualized by 201Tl-S, in 11 patients some but not all lesions were detected. In six patients none of the lesions were detected by 201Tl-S. In four patients, four additional lesions were initially found by 201Tl-S only. After irradiation, 83 of the total 86 positive regions reached a complete or partial remission by CSS. Eighty-one of these were also diagnosed as remission by 201Tl-S and two as stable disease. In 31 out of 35 patients (89%; 95% CI: 73-97%) the overall response in all irradiated sites was identical by 201Tl-S and CSS. Only two patients, in remission on CSS modalities, showed stable disease on 201Tl-S, while two others were diagnosed as CR by CSS and PR by 201Tl-S. CONCLUSIONS: 201Tl-S has limited additional value in staging FL patients, since only two-thirds of all localizations are detected. However, 201Tl-S is accurate in monitoring radiation treatment response in FL patients. If an FL patient with a positive 201Tl-S at diagnosis is treated by irradiation, the treatment response can be reliably ascertained by only performing a 201Tl-S.

Adult↗
PubMed2006

A novel performance descriptor for ultrasonic strain imaging: a preliminary study.

Ultrasonic strain imaging that uses signals from conventional diagnostic ultrasound systems is capable of showing the contrast of tissue elasticity, which provides new diagnostically valuable information. To assess and improve the diagnostic performance of ultrasonic strain imaging, it is essential to have a quantitative measure of image quality. Moreover, it is useful if the image quality measure is simple to interpret and can be used for visual feedback while scanning and as a training tool for operator performance evaluation. This report describes the development of a novel quantitative method for systematic performance assessment that is based on the combination of measures of the accuracy of motion tracking and consistency among consecutive strain fields. The accuracy of motion tracking assesses the reliability of strain images. The consistency among consecutive strain images assesses the signal quality in strain images. The clinical implications of the proposed method to differentiate good or poor strain images are discussed. Results of experiments with tissue-mimicking phantoms and in vivo breast-tissue data demonstrate that the performance measure is a useful method for automatically rating elasticity image quality.

Algorithms↗
PubMed2004

In vitro assays for the diagnosis of IgE-mediated disorders.

Advances in technology have provided new laboratory tools for the quantitation of allergen-specific IgE antibodies in serum and on the surface of basophils. This review examines the evolution from qualitative IgE antibody assays of the late 1960s to the present-day, third-generation, automated and quantitative allergen-specific IgE assays. The latest technology trend is toward microarrays in which crude or purified native and recombinant allergens can be spotted in microdot arrays on silica chips to permit extensive panels of specific IgE measurements to be performed with small quantities of serum. Although these technologies hold promise, their diagnostic performance requires further assessment once their technical details have been optimized. Potential abuses of this newer IgE antibody technology include the use of allergosorbent specificities (eg, especially food and drugs) that lack validation, application of IgE antibody measurements in the diagnosis of non-IgE-dependent disorders (eg, aspirin sensitivity), and modification of IgE antibody assays to measure food-specific IgG antibody for which there is no clinical indication. Basophil mediator release assays have evolved to include flow cytometric methods that can quantitatively detect the presence of cell surface-bound allergen-specific IgE antibodies. Assays for histamine and leukotriene C 4 released after in vitro basophil activation are now more accurate and standardized. Current analytic methods for IgE antibodies provide more quantitative and reproducible measurements of IgE than ever before, although still with less sensitivity that traditional skin testing. The current challenge is to translate the quantitative IgE antibody results into a more accurate diagnosis of allergic disease.

Allergens↗
PubMed1995

[Peripheral occlusive arterial diseases: comparison of diagnostic value of MRA and DSA].

MATERIAL AND METHODS: In 59 patients with arterial flow disturbances 2-D inflow sequence of the abdominal and lower leg arteries were prospectively obtained on a 1.5 T MR-imager and were compared with additional DSA examinations. Supplementary Phase Contraste RSE ("Rapid Sequential Excitation") sequences were carried out in 29 patients. MRA and DSA angiograms were evaluated in random order by 4 readers using a questionnaire. The assessment of image quality were evaluated by variance analysis. Diagnostic performance of MRA and DSA was assessed by comparison of the readers' diagnostic assessments with reference diagnoses established by a radiologist and a vascular surgeon with full knowledge of all data concerning a patient. Image quality of inflow MRA was considered inferior to i.a. DSA (p < 0.001) and comparable with i.v. DSA (p = 0.1361). Image quality of RSE-MRA was inadequate (p < 0.001). Correspondingly, i.a. DSA was the superior and RSE-MRA the inferior imaging technique. The accuracy of inflow MRA in determining stenosis grade was 66% and that of RSE-MRA 59%.

Aged↗
PubMed2000

Urinary N-acetyl-beta-D-glucosaminidase and neopterin aid in the diagnosis of rejection and acute tubular necrosis in initially nonfunctioning kidney grafts.

AIM: The study aimed at investigating urinary neopterin, a marker of cellular immune response, and urinary N-acetyl-beta-D-glucosaminidase (NAG), a marker of tubular damage, as noninvasive means to differentiate between acute tubular necrosis (ATN) and rejection in initially nonfunctioning (INF) human renal transplants. METHODS: Seventy-two renal transplant patients were studied. Forty-five of them experienced an uncomplicated early posttransplant course, 27 patients suffered from INF. Twenty-two patients experienced ATN, 5 patients had a total of six biopsy-proven rejections. The NAG activity was measured by a colorimetric assay, neopterin by high-performance liquid chromatography. Receiver operating characteristics (ROC) analysis was applied to compute diagnostic performance and an optimal discriminating threshold. RESULTS: Demographic characteristics (age, gender, cold and warm ischemia periods, HLA mismatches) and posttransplant urinary NAG and neopterin excretions did not differ between ATN and rejection groups. Both urinary NAG and neopterin excretions were lower in the control group (NAG 1.8 +/- 1.0 U/mmol urinary creatinine; neopterin 270 +/- 126 nmol/mmol urinary creatinine; mean +/- SD) as compared with the ATN group (NAG 12 +/- 10 U/mmol, p < 0.001 vs. control group; neopterin 303 +/- 195 nmol/mmol, n.s.) and the rejection group (NAG 7 +/- 8 U/mmol, p < 0. 01; neopterin 508 +/- 419 nmol/mmol, p < 0.01). The ratio of urinary neopterin to NAG excretion (uNNR; dimension nmol neopterin/U NAG activity) increased during rejections as compared with ATN (139 +/- 74 vs. 50 +/- 38 nmol/U, p < 0.01). The area under the ROC curve for uNNR was 0.88 +/- 0.07 (p < 0.001). Applying a ROC-estimated optimal discriminator of uNNR (80 nmol/U), 16 patients with ATN and all six rejection episodes were classified correctly. CONCLUSION: The uNNR provides a noninvasive means to aid in the differential diagnosis of rejection and ATN in INF human renal transplants.

Acetylglucosaminidase↗
PubMed1982

Combined percutaneous diagnostic puncture and management of renal cysts.

Significant reduction in size was obtained in 12 of 14 renal cysts treated by the instillation of iophendylate. The advent of noninvasive methods has increased the number of renal cysts detected radiologically and has limited the indication for diagnostic puncturing to problematic cases only. However, if it is decided to perform diagnostic puncture of a renal cyst, the combined instillation of iophendylate into the cyst seems to be therapeutically rewarding.

Aged↗
PubMed1995

[Evaluation of the teaching of echo-endoscopy. Application to the assessment of invasiveness of cancer of the esophagus and the cardia].

OBJECTIVES: Learning endosonography (EES) is known to be difficult, and the theory must be understood before performing EES routinely. The aim of the study was to evaluate the diagnostic indexes of EES in the staging of cardio-oesophageal cancer after a period of theoretical apprenticeship of EES and a learning period in a centre experienced in EES since 1989. METHODS: Five observers, having never used EES, followed to EES examinations for a 3-6 month period. They then reviewed the standardized records of 29 patients with cardio-oesophageal cancer. They had to evaluate the degree of tumour infiltration within oesophageal wall and the site of metastatic lymph nodes. Results were compared with the diagnosis of 5 experienced senior endoscopists. Interobserver agreement was estimated with kappa statistics and considered excellent for k > or = 0.75, good to moderate if 0.75 > k > or = 0.40, and poor if k < 0.40. RESULTS: Inter-observer agreement was poor for the topographic diagnosis of lymph nodes (kappa index from -0.09 to 0.33), lower to that of the 5 senior observers (0.33 to 0.77). It was satisfactory for degree of tumour infiltration (T1: k = 0.66; T2: k = 0.58; T3: k = 0.56; T4: k = 0.46). The individual sensitivities were weak according to lymph nodes site, but good for presence of lymph nodes (86 to 100%), with a specificity of 40 to 73%. CONCLUSIONS: After theoretical training of EES, agreement and diagnostic performances are good enough to diagnose pathological images (except for T4 tumors), and poor for localizing images in the mediastinum. This emphasizes the difficulties in learning echo-anatomy and gives useful guidelines for training programs in EES.

Cardia↗