Positive Predictive Value For Detection Research Articles

Thyroid Cytology and Risk of Thyroid Cancer: Differences Among Indeterminate Specimens

To assess the potential for stratification of indeterminate cytologic findings on fine-needle aspiration (FNA) of thyroid nodules in an effort to improve therapeutic strategies. We attempted to determine the malignant risk associated with various indeterminate FNA cytologic patterns by correlation of specimens with the final histologic diagnosis. For this analysis, we identified 294 computerized medical records of surgically treated thyroid nodules during a 5-year period at our institution with the corresponding FNA cytology reports available. Of the 294 surgical cases, 162 with a positive or indeterminate cytologic report were selected, reviewed, and classified. Of 52 patients with positive cytologic findings on FNA, 51 (98%) had a final histologic report of a malignant thyroid nodule. Of 110 patients with indeterminate specimens, 30 (27%) had a final histologic diagnosis of thyroid carcinoma. The presence of nuclear atypia was predictive of thyroid carcinoma in 75% of patients, a Hürthle cell cytologic pattern was associated with a malignant thyroid nodule in 33%, and a hypercellular smear was suggestive of malignant involvement in 26% of cases. The lowest rate of malignant potential was associated with cytologic microfollicular and scant colloid alone subtype (6%). The results of this study show that indeterminate thyroid cytologic specimens can be subdivided into groups with different malignant risks. A microfollicular cytologic pattern in the absence of a hypercellular smear or nuclear atypia does not support a recommendation of surgical treatment. A malignant cytologic diagnosis has a high positive predictive value for detection of thyroid cancer.

Does methylene blue detect intestinal metaplasia in Barrett's esophagus?

Methylene blue has been used to selectively stain areas of specialized intestinal metaplasia in Barrett's esophagus. The sensitivity, specificity, and negative and positive predictive values for the detection of specialized intestinal metaplasia by methylene blue chromoendoscopy were determined in patients with Barrett's esophagus. Thirty patients with Barrett's esophagus underwent endoscopy with biopsy specimens obtained from areas that stained positive and negative with methylene blue. Histopathologic findings were compared with methylene blue chromoendoscopy findings. Two hundred ninety-two biopsy specimens (mean 9.7/patient) were obtained: 203 from stained and 89 from unstained areas. Sensitivity, specificity, and negative and positive predictive values for detection of specialized intestinal metaplasia were, respectively, 72%, 46%, 22%, and 89%. Comparing 187 biopsy specimens from patients with long-segment Barrett's esophagus with 105 specimens from patients with short-segment Barrett's esophagus, the sensitivity, specificity, and negative and positive predictive values were, respectively, 77% versus 63% (p = 0.044), 79% versus 21% (p < 0.002), 28% versus 14% (p = 0.219), and 97% versus 73% (p < 0.002). The odds ratio for detection of specialized intestinal metaplasia in stained areas was 12.40 in long-segment and 0.45 in short-segment Barrett's esophagus. Data from this study confirm the value of methylene blue chromoendoscopy for detection of specialized intestinal metaplasia in long-segment Barrett's esophagus, but not in short-segment Barrett's esophagus.

Echocardiographic Indices of Doppler Flow Patterns Compared with MRI or Angiographic Measurements to Detect Significant Coarctation of the Aorta

Evaluation for the presence and severity of coarctation of the aorta (CoA) by two-dimensional echocardiography alone can be difficult. The purpose of this study was to use Doppler velocity and pressure gradient half-time in systole and diastole to estimate CoA severity. Doppler echocardiograms of children with suspected CoA and either an aortic angiogram or thoracic magnetic resonance imaging (MRI) performed within 1 month of the echocardiogram were evaluated. Patients with patent ductus arteriosus, significant aortic insufficiency, long tubular CoA, or CoA outside the thorax were excluded. Measured Doppler variables, indexed for heart rate, included systolic velocity half-time (sVHTi), diastolic velocity half-time (dVHTi), systolic pressure half-time (sPHTi), and diastolic pressure half-time (dPHTi). For each of these variables, sensitivity and specificity to detect a significant CoA were determined. A significant CoA was defined as a ratio of the CoA diameter to the diaphragmatic aortic diameter of < 0.5 as imaged by MRI or angiography. Indexed systolic velocity and pressure half-times were found not to be significant predictors for CoA. For the Doppler parameter dVHTi, using a critical value of > 200 msec indexed, we found a positive predictive value of 87% and a negative predictive value of 80%. The parameter dPHTi, using a critical value of > 75 msec indexed, demonstrated positive and negative predictive values of 92% and 79%, respectively. Measurement of dVHTi is a useful predictor for significant CoA, but the parameter dPHTi has an improved positive predictive value for detection of significant CoA. Systolic measurements of velocity or pressure half-times are not adequate to assess severity of CoA.

Evaluation of duplex ultrasound and captopril renography for detection of renovascular hypertension

Renovascular hypertension is the most common form of curable secondary hypertension and, if untreated, may lead to end-stage kidney disease. Given that renal function and hypertension may improve after renal angioplasty, it is pertinent to identify patients with renal artery stenosis. The aim of the present study was to evaluate both duplex ultrasound and captopril renography for detection of renal artery stenosis among hypertensive patients. To avoid selection bias, all patients referred to our center for evaluation of renovascular hypertension were asked to participate in the study. Patients were examined by intra-renal duplex ultrasound (N = 121), measuring pulsatility index and acceleration of the blood flow during early systole. In 98 patients, 99mTc-DTPA captopril renography was performed in conjunction with duplex ultrasound. Renal angiography was performed in all patients regardless of the results of the noninvasive tests. The prevalence of renal artery stenosis was 19%. In the 98 patients examined by both duplex ultrasound and captopril renography, sensitivity and positive predictive values for detection of a renal artery stenosis of 50% degree or more were 84 and 76%, respectively, for duplex ultrasound, whereas captopril renography was associated with a sensitivity and positive predictive value of 68% for both (P = NS). Specificity and negative predictive values were 94 and 96%, respectively, for duplex ultrasound, whereas the corresponding values for captopril renography were 92% for both (P = NS). Specificity and negative predictive values were 94 and 96%, respectively, for duplex ultrasound, whereas the corresponding values for captopril renography were 92% for both (P = NS). Both duplex ultrasound and captopril renography are associated with high specificity and negative predictive values for detection of renal artery stenosis. Sensitivity and positive predictive values are at least as good for duplex ultrasound compared with captopril renography. Given that duplex ultrasound is easier to perform and more cost effective, we propose that it should be the method of first choice when screening for renal artery stenosis in a hypertensive population.

HPV DNA Testing in Cervical Cancer Screening: Results From Women in a High-Risk Province of Costa Rica

ContextHuman papillomaviruses (HPVs) are known to cause most cervical cancer worldwide, but the utility of HPV DNA testing in cervical cancer prevention has not been determined.ObjectiveTo provide comprehensive data on the screening performance of HPV testing for the most common carcinogenic types, at different levels of analytic sensitivity.DesignLaboratory analysis conducted during 1993-1995, using 3 cytologic techniques and cervicography, followed by colposcopic examination of women with any abnormal cervical finding, to detect all high-grade intraepithelial lesions and cancer (reference standard of clinically significant disease). The HPV testing was performed subsequently with masking regarding clinical findings.SettingGuanacaste Province, Costa Rica, a region with a high age-adjusted incidence of cervical cancer.ParticipantsOf 11,742 randomly selected women, 8554 nonpregnant, sexually active women without hysterectomies underwent initial HPV DNA testing using the original Hybrid Capture Tube test; a stratified subsample of 1119 specimens was retested using the more analytically sensitive second generation assay, the Hybrid Capture II test.Main Outcome MeasuresReceiver operating characteristic analysis of detection of cervical high-grade intraepithelial lesions and cancer by HPV DNA testing based on different cut points of positivity.ResultsAn analytic sensitivity of 1.0 pg/mL using the second generation assay would have permitted detection of 88.4% of 138 high-grade lesions and cancers (all 12 cancers were HPV-positive), with colposcopic referral of 12.3% of women. Papanicolaou testing using atypical squamous cells of undetermined significance as a cut point for referral resulted in 77.7% sensitivity and 94.2% specificity, with 6.9% referred. Specificity of the second generation assay for positivity for high-grade lesions and cancer was 89.0%, with 33.8% of remaining HPV DNA–positive subjects having low-grade or equivocal microscopically evident lesions. The higher detection threshold of 10 pg/mL used with the original assay had a sensitivity of 74.8% and a specificity of 93.4%. Lower levels of detection with the second generation assay (<1 pg/mL) proved clinically nonspecific without gains in diagnostic sensitivity.ConclusionsIn this study population, a cut point of 1.0 pg/mL using the second generation assay permitted sensitive detection of cervical high-grade lesions and cancer, yielding an apparently optimal trade-off between high sensitivity and reasonable specificity for this test. The test will perform best in settings in which sensitive detection of high-grade lesions and cancer is paramount. Because HPV prevalence varies by population, HPV testing positive predictive value for detection of high-grade lesions and cancer will vary accordingly, with implications for utility relative to other cervical cancer screening methods.

HPV DNA testing in cervical cancer screening: results from women in a high-risk province of Costa Rica.

Human papillomaviruses (HPVs) are known to cause most cervical cancer worldwide, but the utility of HPV DNA testing in cervical cancer prevention has not been determined. To provide comprehensive data on the screening performance of HPV testing for the most common carcinogenic types, at different levels of analytic sensitivity. Laboratory analysis conducted during 1993-1995, using 3 cytologic techniques and cervicography, followed by colposcopic examination of women with any abnormal cervical finding, to detect all high-grade intraepithelial lesions and cancer (reference standard of clinically significant disease). The HPV testing was performed subsequently with masking regarding clinical findings. Guanacaste Province, Costa Rica, a region with a high age-adjusted incidence of cervical cancer. Of 11742 randomly selected women, 8554 nonpregnant, sexually active women without hysterectomies underwent initial HPV DNA testing using the original Hybrid Capture Tube test; a stratified subsample of 1119 specimens was retested using the more analytically sensitive second generation assay, the Hybrid Capture II test. Receiver operating characteristic analysis of detection of cervical high-grade intraepithelial lesions and cancer by HPV DNA testing based on different cut points of positivity. An analytic sensitivity of 1.0 pg/mL using the second generation assay would have permitted detection of 88.4% of 138 high-grade lesions and cancers (all 12 cancers were HPV-positive), with colposcopic referral of 12.3% of women. Papanicolaou testing using atypical squamous cells of undetermined significance as a cut point for referral resulted in 77.7% sensitivity and 94.2% specificity, with 6.9% referred. Specificity of the second generation assay for positivity for high-grade lesions and cancer was 89.0%, with 33.8% of remaining HPV DNA-positive subjects having low-grade or equivocal microscopically evident lesions. The higher detection threshold of 10 pg/mL used with the original assay had a sensitivity of 74.8% and a specificity of 93.4%. Lower levels of detection with the second generation assay (<1 pg/mL) proved clinically nonspecific without gains in diagnostic sensitivity. In this study population, a cut point of 1.0 pg/mL using the second generation assay permitted sensitive detection of cervical high-grade lesions and cancer, yielding an apparently optimal trade-off between high sensitivity and reasonable specificity for this test. The test will perform best in settings in which sensitive detection of high-grade lesions and cancer is paramount. Because HPV prevalence varies by population, HPV testing positive predictive value for detection of high-grade lesions and cancer will vary accordingly, with implications for utility relative to other cervical cancer screening methods.

Mediastinal Evaluation Utilizing the Reverse Trendelenburg Radiograph

When thoracic aortic rupture is suspected, a 45-degree reverse Trendelenburg (RT) anteroposterior (AP) chest radiograph should place the mediastinal structures in a more appropriate position and allow a more accurate evaluation than a supine AP radiograph. One hundred ninety-one consecutive hemodynamically stable adult patients with major blunt thoracic trauma were initially evaluated for mediastinal abnormalities associated with aortic disruption by both supine AP chest radiograph and an AP chest radiograph with the patient in 45-degree RT position. One hundred four patients underwent contrast aortography based on mediastinal abnormalities detected on the supine AP chest radiograph. Twenty of these patients had abnormal aortograms demonstrating traumatic aortic disruption confirmed at surgery. Supine and RT chest radiographs were retrospectively compared in a blinded fashion to evaluate their specificity and positive predictive value for detection of traumatic thoracic aortic rupture. If RT chest radiographic findings had been used to determine the need for further assessment, 29 angiograms (26%) would have been eliminated, specificity would have increased from 52 per cent to 69 per cent, and positive predictive value would have increased from 19 per cent to 27 per cent. Both supine and RT chest radiographs demonstrated mediastinal widening in all 20 patients with abnormal aortograms, with no missed thoracic aortic disruptions (100% sensitivity). This study indicated that the RT chest radiograph may be used instead of the standard supine radiograph as the initial screen for mediastinal evaluation, maintaining a high sensitivity and eliminating the cost and morbidity of many unnecessary aortograms.

Second trimester ultrasound screening performed by midwives; sensitivity for detection of fetal anomalies

To assess the sensitivity for detection of fetal anomalies by a second trimester ultrasound screening program performed in a way representative of a majority of Swedish obstetrical departments. The examinations were performed at the ultrasound division of the Department of Obstetrics and Gynecology at the University Hospital of Uppsala, Sweden. A prospective study covering a two-year period. Eight thousand two hundred and twenty-eight unselected, consecutive pregnant women (8345 fetuses) were examined. The ultrasound scans were performed at a gestational age of 15-22 weeks by specially trained midwives. All fetal anomalies suspected at the ultrasound screening were recorded. Follow-up of all scanned fetuses was done through neonatal reports, records from the pediatric department, a national malformation registry and autopsies. All live-born infants were followed one year after birth. Main outcome measures were sensitivity, specificity, and positive predictive value for detection of fetal anomalies and prevalence of fetal anomalies. In all 145 fetuses/infants with confirmed anomalies were identified (prevalence 1.7%). Thirty-two were detected by second trimester ultrasound screening (sensitivity 22.1%). Twenty false positive cases were identified, of which fifteen were ruled out on the same day the suspicion arose and five were transient findings. The specificity was 99.8% and the positive predictive value 61.5% When performing a second trimester ultrasound screening program, prenatal diagnosis of fetal anomalies will be part of the procedure whether this is a primary aim or not. It is therefore of great importance that the pregnant women receive adequate information and that the voluntariness of participation is stressed. In this study the sensitivity was low. Standardizing the scanning procedure (check-list for fetal anatomy) and improving the education of the operators are feasible ways to increase the sensitivity.

Multicenter radioimmunoscintigraphic evaluation of patients with prostate carcinoma using indium-111 capromab pendetide

Optimum therapy for prostate carcinoma patients requires accurate staging, but computed tomography (CT) and magnetic resonance imaging (MRI) have limitations as methods for detecting soft tissue metastases. In this study, radioimmunoscintigraphy (RIS) was evaluated for its ability to identify sites of metastatic disease in lymph nodes. RIS was evaluated in 51 prostate carcinoma patients at high risk for metastatic disease. An intravenous infusion of indium-111 capromab pendetide was given, followed by nuclear medicine imaging on two separate dates. Bilateral, open pelvic lymph node dissection was performed with additional exploration and biopsy of scan positive extraprostatic regions. Histologic evaluation of removed tissue confirmed the accuracy of RIS. In addition, results were compared with other standard methods for diagnosing patients prior to surgery. Nineteen patients (37%) had evidence of lymph node involvement with RIS. Fifteen of the 19 positive patients had pathologic evidence of cancer in the biopsied lymph nodes. Sensitivity, specificity, accuracy, and the positive predictive value for detection of extraprostatic disease were 75%, 86%, 81%, and 79%, respectively. CT, MRI, and ultrasound of the pelvis demonstrated a combined accuracy of only 48% in detecting lymph node disease. Twenty-five previously undetected sites were deemed positive with RIS. Fourteen of these were biopsy-proven tumor sites, seven were probable tumor sites, and four were assumed to be false-positive. RIS had an impact on patient management through its detection of occult disease in more than 50% of prostate carcinoma patients studied, and it provided information concerning the likelihood that lymph node metastases would be found during surgery.

Nonpalpable, probably benign lesions: role of follow-up mammography.

Of 21,855 consecutive women prospectively studied with mammography, physical examination, and high-resolution ultrasonography when appropriate, 558 received a diagnosis of nonpalpable, probably benign lesions. Follow-up mammography was recommended for these patients. Characteristically benign lesions and palpable masses were excluded from analysis. The positive predictive value for detection of a nonpalpable, probably benign breast lesion was 0.017. Nine patients ultimately proved to have carcinoma; two of them had noninvasive carcinoma, and two had axillary node metastases. The positive predictive value for detection of a nonpalpable, probably malignant lesion was 0.47. The policy of recommending mammographic surveillance for nonpalpable, probably benign lesions, a viable option for radiologists, has the capability of lowering the rate and therefore the costs of biopsy procedures with negative results.

Diagnostic Studies in Patients With Sickle Cell Anemia and Acute Abdominal Pain

Twenty-eight patients with sickle cell disease who presented with acute abdominal pain were evaluated with clinical laboratory, ultrasound, and biliary scintigraphic studies to determine their predictive capabilities for differentiating veno-occlusive disease (sickle cell crisis) from acute biliary disease. Eleven patients were treated surgically and 17 medically. Gallstones were demonstrated in 25 (90%) of the patients studied by ultrasound, and biliary scans were abnormal in nine patients (32%). Abnormal laboratory and radiological studies (ultrasound, biliary scintigraphy) were not significantly different in the two groups and had a low positive predictive value for detection of acute biliary disease. Nevertheless, normal biliary scintigraphy had high negative predictive value in that, if normal, it gave assurance that the cystic duct was patent and unnecessary surgery could be obviated in this high-risk category of patients.