Biomedical subjects

T M Silver

Publications and source records attributed to T M Silver.

At least 19 recordsLinked to original sources

PubMed2001

Evaluation of competence in the interpretation of chest radiographs.

RATIONALE AND OBJECTIVES: The purpose of this study was to determine relative rates of missed diagnoses for radiologists as a measure of competence in interpreting chest radiographs. MATERIALS AND METHODS: Cases involving differing interpretations of chest radiographs were collected from January 1994 through December 1999 by faculty (chest and nonchest radiology specialists) in an academic radiology department. A quarterly peer-review process designated cases months after the fact, and anonymously, as no miss or as class I (nondiagnosable), class II (very difficult diagnosis), class III (should be diagnosed most of time), or class IV (should almost always be diagnosed) missed diagnoses. The rates and classes of missed diagnoses were compared among chest faculty and for the nonchest radiology specialists as a group. RESULTS: Chest radiologists read 184,977 studies, and nonchest radiologists read 300,684 studies. Of these, 243 missed diagnoses were classified (classes I and II, 184 cases; class III, 50; and class IV, nine). No difference was detected in the rate of class III and IV misses among chest faculty, but nonchest faculty had significantly more class III (P = .022) and class IV misses (P = .016). CONCLUSION: Random sampling of differing interpretations can yield a relative rate of missed diagnoses for radiologists. No difference was detected in clinically important misses (ie, classes III and IV) among chest radiologists, but a statistically significantly higher rate of seemingly obvious misdiagnoses was found for nonchest specialty radiologists. Potential biases may have influenced this analysis, including disease prevalence, sampling, clinical factors, observer variability, and truth-in-diagnosis.

Clinical Competence↗

PubMed2000

Safety and efficacy of percutaneous coronary interventions performed immediately after diagnostic catheterization in northern new england and comparison with similar procedures performed later.

"Ad hoc" percutaneous coronary interventions (PCIs)-those performed immediately after diagnostic catheterization-have been reported in earlier studies to be safe with a suggestion of higher risk in certain subgroups. Despite increasing use of this strategy, no data are available in recent years with new device technology. We studied use of an ad hoc strategy in a large regional population to determine its use and outcomes compared with staged procedures. A database from the 6 centers performing PCIs in northern New England and 1 center in Massachusetts was analyzed. During 1997, excluding only patients requiring emergency procedures or those with a prior PCI, 4,136 PCIs were performed, 1,748 (42.3%) of these being ad hoc procedures. Patients having ad hoc procedures were less likely to have peripheral vascular disease, renal failure, prior myocardial infarction, or coronary artery bypass surgery, congestive heart failure, or poor left ventricular function, and more likely to have received preprocedural intravenous heparin or nitroglycerin or to have required an urgent procedure. Narrowings treated during ad hoc procedures were less frequently types B and C or in saphenous vein grafts. Adjusted rates of clinical success were not different between ad hoc and non-ad hoc procedures (93.7% vs 93.6%); there was no difference in the incidence of death (0.6% vs 0.5%), emergency (0. 9% vs 0.8%) or any (1.4% vs 0.8%) coronary artery bypass surgery, or myocardial infarction (2.6% vs 2.0%). As currently practiced in our region, ad hoc intervention is used selectively with outcomes similar for ad hoc and non-ad hoc procedures.

Angina Pectoris↗

PubMed2000

Functional outcome for African Americans and Hispanics treated at a traumatic brain injury model systems centre.

OBJECTIVE: To describe the demographics, incidence and functional outcome for African Americans and Hispanics treated at a traumatic brain injury (TBI) model systems centre. DESIGN: Retrospective data analysis of patients admitted to an acute inpatient rehabilitation national TBI model systems centre. SETTING: A tertiary care university medical centre participating in the NIDRR Traumatic Brain Injury Model Systems project. SUBJECTS: Eighty-seven patients with TBI admitted to a Model Systems acute intensive interdisciplinary rehabilitation setting between 1989-1999. Information was extracted from the National TBI Model Systems data base for demographics such as age, race, education, gender, marital and employment status, sponsorship, injury aetiology and severity. OUTCOME MEASURES: Functional outcome was determined using the Functional Independence Measure (FIM), and the Disability Rating Scale (DRS) at the time of admission and discharge. RESULTS: Descriptive statistics were completed using SPSS. African American (94.3%) and Hispanic (5.7%) patients were injured most often as a result of motor vehicle accidents (48.8%). Males comprised 86.2% of this population, which had an average age of 34.5 years (SD = 13.1). On admission, average GCS score was 7.8 (SD = 3.6), average DRS was 13.5 (SD = 5.8), and average FIM total score was 49.8 (SD = 26.5). Average length of unconsciousness was 5.2 days (SD = 27.9), while average length of post-traumatic amnesia was 41.9 days (SD = 59.3). At the time of injury, 78.2% of the patients were not married. The majority of patients (97.7%) had private residences and 88.5% returned to their original home. Most patients had at least a high school education or passed a high school equivalent exam (49.4%) and were employed (70.1%) at the time of injury. Only 7% of the patients had a history of prior TBI. With regard to substance use, only 34.2% of patients reported pre-morbid illicit drug use. However, 50.5% met criteria for heavy or moderate alcohol use rates. Only 35.6% of patients reported a pre-morbid history of arrests, with the average number of arrests equal to 4.5 (SD = 10.2). Within this population, the number of drug or alcohol related arrests was 4.8 (SD = 13.5). CONCLUSIONS: Unmarried African American males, with an average age of 35 years, predominated at this institution. The primary mechanism of injury was motor vehicle accidents. The majority of patients had, at least, a high school education or passed an equivalency exam, were employed at the time of their injury and were discharged to their prior private residence. While half of the patients met criteria for moderate-to-heavy alcohol consumption, only one-third of the patients reported a history of pre-morbid illicit drug use. This descriptive analysis supports the need for further investigation of minority populations that sustain TBI and will enhance the accuracy of implications that minority status may have on functional outcome.

Activities of Daily Living↗

PubMed1999

The relationship between operator volume and outcomes after percutaneous coronary interventions in high volume hospitals in 1994-1996: the northern New England experience. Northern New England Cardiovascular Disease Study Group.

OBJECTIVES: The purpose of this study was to examine the relationship between annual operator volume and outcomes of percutaneous coronary interventions (PCIs) using contemporaneous data. BACKGROUND: The 1997 American College of Cardiology (ACC)/American Heart Association task force based their recommendation that interventionists perform > or = 75 procedures per year to maintain competency in PCI on data collected largely in the early 1990s. The practice of interventional cardiology has since changed with the availability of new devices and drugs. METHODS: Data were collected from 1994 through 1996 on 15,080 PCIs performed during 14,498 hospitalizations by 47 interventional cardiologists practicing at the five high volume (>600 procedures per hospital per year) hospitals in northern New England and one Massachusetts-based institution that support these procedures. Operators were categorized into terciles based on their annualized volume of procedures. Multivariate regression analysis was used to control for case-mix. In-hospital outcomes included death, emergency coronary artery bypass graft surgery (eCABG), non-emergency CABG (non-eCABG), myocardial infarction (MI), death and clinical success (> or = 1 attempted lesion dilated to < 50% residual stenosis and no death, CABG or MI). RESULTS: Average annual procedure rates varied across terciles from low = 68, middle = 115 and high = 209. After adjusting for case-mix, clinical success rates were comparable across terciles (low, middle and high terciles: 90.9%, 88.8% and 90.7%, Ptrend = 0.237), as were all the adverse outcomes including death (low-risk patients = 0.45%, 0.41%, 0.71%, Ptrend = 0.086; high-risk patients = 5.68%, 5.99%, 7.23%, Ptrend = 0.324), eCABG (1.74%, 2.05%, 1.75%, Ptrend = 0.733) and MI (2.57%, 1.90%, 1.86%, Ptrend = 0.065). CONCLUSIONS: Using current data, there is no significant relationship between operator volumes averaging > or = 68 per year and outcomes at high volume hospitals. Future efforts should be directed at determining the generalizability of these results.

Angioplasty, Balloon, Coronary↗

PubMed1998

Innervation of the supranasal sac of the puff adder.

BACKGROUND: The supranasal sac is an invagination of the skin between the supranasal and nasal shields of many true vipers. Viperinae behavior suggests that many true vipers hunt by thermal cues. METHODS: The supranasal sacs of two puff adder (Serpentes: Viperinae) were examined with modern histological and neurohistological techniques, including Kiernan's silver stain. RESULTS: There are nerve endings in the supranasal sac of the puff adder that resemble the nerve endings in the labial pits of boas. CONCLUSION: This suggests that the supranasal sac of true vipers is, like the labial pits of boas, a heat detector.

Animals↗

PubMed1995

Influence of low-level cadmium and reduced calcium intake on tissue Cd concentrations and behaviour of American black ducks.

Populations of American black ducks have declined and it has been hypothesized that wetland acidification, which can alter food quality by increasing availability of cadmium and decreasing that of calcium, may have contributed. We tested whether low-level cadmium and reduced calcium intake affect tissue cadmium concentrations and behaviour of captive black ducks. Adults received diets that mimicked cadmium and calcium concentrations in invertebrate prey from acid and from circumneutral wetlands for three spring and summer months in 1991 and 1992. Behaviours were monitored both when birds were fed experimental diets and control (commercial) diets. Cadmium in kidneys and liver differed significantly among groups and low calcium facilitated cadmium uptake. After two breeding seasons, levels of accumulated Cd were not lethal. However, birds that received Cd were significantly more active than control birds. Increased activity may have implications for survival of birds in the wild.

Journal Article↗

PubMed1991

Ultrasonography of liver. Technique and focal and diffuse disease.

Because of its widespread use and availability, ultrasonography is frequently the first test used to assess patients with focal or diffuse hepatic disease. While ultrasonographic features of hepatic lesions often do not allow for a specific diagnosis, this article demonstrates typical ultrasonographic features of commonly encountered disease entities as an aid to differential diagnosis. Recent advances, including Doppler and intraoperative ultrasonography also are discussed.

Humans↗

PubMed1989

Ovarian torsion: sonographic evaluation.

The sonographic and clinical findings of 13 patients with surgically proven ovarian torsion are reported. Sonography demonstrated an abnormal pelvic mass in all patients. The appearance was nonspecific, ranging from solid to cystic, but frequently reflected the commonly associated ovarian pathology present in 69% of patients. The mass was large (mean diameter: 8 cm) and frequently midline (8/13). The clinical findings were variable and nonspecific, leading to a correct preoperative differential diagnosis in only 35% of patients. Preoperative sonography reduced the likelihood of unnecessary appendectomy in patients with ovarian torsion.

Adolescent↗

PubMed1989

Assessment of ultrasonic computed tomography in symptomatic breast patients by discriminant analysis.

From 95 subjects imaged with both speed of sound and attenuation ultrasonic computed tomography (UCT), quantitative analyses are presented on 40 cases where unequivocal correlating clinical diagnoses are available. Using four attenuation and speed of sound parameters from different regions of interest in the breast, a linear discriminator detects cancer with approximately 90% sensitivity and specificity. Increased confidence in the predictive power of this small study is given by a modern test of predictive power (jackknifing) and by the fact that diagnostic discrimination remains as high as 85% when only two parameters are employed--attenuation and speed of sound in the lesion minus those values in the remaining central mammary tissues. Speed of sound images appear particularly useful in older, fatty breasts where pulse echo ultrasound is particularly lacking. While UCT in the form studied here is not likely to receive wide clinical acceptance in the near future, a combined UCT/pulse echo system might find wide clinical utility if it can be sufficiently convenient and inexpensive.

Adenofibroma↗

PubMed1988

The distinction between femoral artery pseudoaneurysms and other causes of groin masses: value of duplex Doppler sonography.

With the increasing use of percutaneous transfemoral coronary angioplasty in conjunction with thrombolytic as well as anticoagulant therapy, the sonographic evaluation of groin masses, with particular emphasis on differentiating pseudoaneurysms from hematomas and other abnormalities, has become more common. Seventy-three sonograms of the groin in 60 patients (65 different groins) were reviewed retrospectively to determine the accuracy of duplex Doppler sonography in distinguishing femoral artery pseudoaneurysm (a surgical condition) from other causes of groin masses (e.g., hematomas) that are generally treated conservatively. Nineteen cases of pseudoaneurysm, 19 cases of hematoma, and 27 other conditions were studied. Of the 73 sonograms performed, 53 included duplex Doppler studies; one Doppler study was false-negative and two were possibly false-positive. The sensitivity, specificity, and accuracy of duplex Doppler sonography in the detection of femoral artery pseudoaneurysm was 95 +/- 5.8%, 94 +/- 6.4%, and 94 +/- 6.4%, respectively (95% confidence limit). We conclude that duplex Doppler sonography is of value in the differential diagnosis of groin masses.

Adult↗

PubMed1986

Ultrasound evaluation of uncommon renal transplant complications.

Twenty-five patients who had undergone renal transplants developed uncommon complications that were detected and followed serially with sonography. Two patients developed renal calculi, which produced hydronephrosis in both instances. Other uncommon causes of postoperative hydronephrosis occurred in 5 cases; the causes included ureteral necrosis, ureteral stricture, and a renocutaneous fistula. Eight cases of renal infarction, manifesting 3 different sonographic appearances, were encountered. The presence and disappearance of postoperative gas in the collecting system were documented in 3 patients. The other unusual abnormalities detected involving the transplanted kidney include tuberculosis, pyonephrosis, 3 solitary cysts, a corpus lutem cyst simulating a perinephric fluid collection, and massive urinary ascites.

Adolescent↗

PubMed1986

Gastric trichobezoar: sonographic findings.

Ultrasonographic diagnosis of trichobezoar may be relatively specific. A broad band of high-amplitude echoes can be seen superficially, with complete sonic shadowing behind. The authors describe a patient in whom the diagnosis was made prior to conventional barium studies and in whom the question of trichobezoar had not been raised clinically.

Bezoars↗

PubMed1986

Postappendectomy fluid collections in children: incidence, nature, and evolution evaluated using US.

At the authors' medical center, most patients with postappendectomy fluid collections are treated conservatively. Thirty-two (15%) of 216 children underwent postoperative sonography following appendectomies. In ten patients (31%), a total of 16 fluid collections were found on the initial postoperative sonogram. In the seven patients (70%) whose fluid collections were confined to the pelvis, the condition was treated conservatively and it resolved in 2-9 weeks. In three patients, fluid collections required surgical drainage and proved to be abscesses. In two of the three patients, abscesses were multiple and widely distributed in the abdomen, and the patients were clinically ill. The authors conclude that clinically symptomatic fluid collections develop postoperatively in approximately 5% of children who have undergone appendectomy for acute appendicitis and that the size and course of the fluid collection can be objectively monitored using sonography. Such fluid collections confined to the pelvis ultimately resolve with conservative, nonoperative therapy, although resolution may take up to 2 months.

Abdomen↗

PubMed1986

Splenic trauma in the pediatric patient: the integrated roles of ultrasound and computed tomography.

Seven children who sustained splenic trauma were scanned by ultrasound and computed tomography (CT) or ultrasound and nuclear liver/spleen scan. All patients were managed conservatively and did not need abdominal surgery. On the initial sonogram, the majority of children had multiple areas of both increased and decreased echogenicity. Hematomas were followed to resolution in five of seven children and were usually multiple and hypoechoic prior to complete disappearance. On contrast-enhanced CT scans, areas of splenic hemorrhage appeared as low attenuation. Our small patient population demonstrates that, following an initial CT scan, sonography is helpful for sequential splenic imaging to show when the appearance of the spleen returns to normal. When correlated with the clinical information, such data are helpful to the clinician in determining when a child who has sustained splenic trauma may resume normal activity.

Adolescent↗

PubMed1985

Congenital uterine anomalies and associated pregnancies: findings and pitfalls of sonographic diagnosis.

Fifteen pregnancies occurring in 13 patients with congenital uterine anomalies were analyzed. The anomalies included bicornuate uteri (nine cases), subseptate uteri (two), septated uteri (one), and uterus didelphys (one). Identification of a bilobed uterine contour with an anterior and/or posterior indentation, an eccentrically located gestational sac, and echogenic endometrial debris in the nongravid horn, reliably indicated a coexistent uterine anomaly. Uterine anomalies became difficult or impossible to identify with increasing gestational age. Entities potentially confused with uterine anomalies include cornual leiomyomata, ectopic gestation, placental septations, and uterine scarring. Awareness of the sonographic findings of pregnancies in anomalous uteri should improve their detection and may alter obstetrical management.

Cesarean Section↗

PubMed1985

Neurosurgical applications of intraoperative ultrasound.

Intraoperative sonography is becoming increasingly important in neurosurgery. In this article, the authors provide step-by-step instructions, the basics of lesion localization, sonographic characteristics of the more common brain and spine lesions, and tables of references to sonographically described lesions in the literature.

Adult↗

PubMed1985

Abdominal and miscellaneous applications of intraoperative ultrasound.

Intraoperative sonography is rapidly becoming a key diagnostic tool within the operative suite. Important applications are defined within the abdomen, vascular system, and other regions of the body. Intraoperative scanning may better define the normal anatomy and target pathology than preoperative studies. As with neurosurgical applications of intraoperative ultrasound, with the use of high-resolution, high-frequency real-time transducers, multiple transducer frequencies within one probe, and probe shapes specifically designed for certain types of operations, it is anticipated that the surgical use of intraoperative ultrasound will greatly increase in the future.

Biliary Tract Diseases↗

PubMed1985

Actuarial analysis of variables associated with rupture of small abdominal aortic aneurysms.

This study identified risk factors associated with rupture of small abdominal aortic aneurysms in patients initially selected for nonoperative management. Sixty-seven patients, 53 men and 14 women, 50 to 91 years of age (mean 72 years) were followed 3 to 99 months (mean 36 months). All patients underwent serial aortic ultrasonography. The annual rate of aneurysm rupture was 6%, with an annual mortality rate caused by rupture of 5% and an annual mortality rate caused by coexistent disease of 6%. Thirty potential risk factors, including blood pressure, aneurysm size measured by ultrasonography, rate of aneurysm expansion, smoking, serum cholesterol levels, and cardiac, pulmonary, and renal risks, were analyzed by Cox proportional hazards regression to identify variables related to rupture. Aneurysm anteroposterior expansion rates varied from 0 to 1.5 cm/year but were not different in aneurysms that ruptured. Only diastolic blood pressure, initial aneurysm anteroposterior diameter, and degree of obstructive pulmonary disease were independently predictive of rupture (p less than 0.05, Wald test). With these data, actuarial rupture rates were predicted for patients with selected values of these three covariates. Predicted 5-year rupture rates varied from 2% when these risk factors were absent to 100% when all three risk factors were significant. Obstructive pulmonary disease, initial aneurysm size, and diastolic hypertension must be evaluated prospectively to assess their accuracy in predicting small aneurysm rupture.

Actuarial Analysis↗