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Biomedical subjects

Robert S Shapiro

Publications and source records attributed to Robert S Shapiro.

8 recordsLinked to original sources
PubMed2006

Hepatic imaging in the 21st century.

Imaging of the liver has progressed rapidly during the past decade with continued advancement of current ultrasound, computed tomography, and magnetic resonance imaging (MRI). Each modality not only has seen refinement enabling better anatomic characterization of disease but also has received strength from the addition of new techniques to its resources. New contrast agents have become available for all modalities and some agents, particularly for MRI, have opened the way for better functional assessment. MRI continues to see an elaboration of sequences (including spectroscopy and diffusion) that also open imaging to the microscopic structure of disease and normal function. The further development of workstations have improved both analysis and depiction of disease. In the 21st century imaging will continue to shift from a simple source of anatomic information to a more functional problem-solving tool.

Cholangiography↗
PubMed2005

Diagnostic value of tissue harmonic imaging compared with conventional sonography.

The purpose of this study was to determine if tissue harmonic imaging (THI) produced diagnostic images more frequently than conventional sonography. A prospective study was performed on 33 patients, to compare the diagnostic value of THI with conventional sonography. Each examination was performed using THI (transmit frequency=2.0 MHz, receive frequency=4.0 MHz) and conventional sonography at 2.5 and 4.0 MHz. The different sonographic techniques were then graded as to whether they produced diagnostic images. THI produced diagnostic images in 33 of 33 examinations (100%), 2.5 MHz conventional sonography produced diagnostic images in 26 of 33 examinations (79%), and 4.0 MHz conventional sonography produced diagnostic images in 26 of 33 examinations (79%). THI produced diagnostic images significantly more frequently than 2.5 MHz conventional sonography (p=.0233) and 4.0 MHz conventional sonography (p=.0233). The THI technique produced diagnostic images more frequently than conventional sonography.

Diagnosis, Computer-Assisted↗
PubMed2004

Effect of prolongation of expiratory time on dynamic hyperinflation in mechanically ventilated patients with severe asthma.

OBJECTIVE: To assess the effect of a decrease in respiratory rate on dynamic hyperinflation, as determined by changes in plateau airway pressure, in patients with status asthmaticus whose baseline minute ventilation approximated 10 L/min. DESIGN: Observational descriptive study. SETTING: Medical intensive care unit. PATIENTS: Twelve patients with severe asthma mechanically ventilated in the assist control mode with a tidal volume of 613 +/- 100 mL and an inspiratory flow rate of 79 +/- 4 L/min. INTERVENTIONS: A decrease in respiratory rate from 18 to 12 and 6 breaths/min. MEASUREMENTS AND MAIN RESULTS: Plateau airway pressure decreased by approximately 2 cm H2O (25.4 +/- 2.8 vs. 23.3 +/- 2.6 cm H2O, p <.01) when respiratory rate was decreased from 18 to 12 breaths/min (increase in expiratory time 1.7 secs) and by a similar amount (23.3 +/- 2.6 vs. 21.3 +/- 2.9 cm H2O, p <.01) when respiratory rate was decreased from 12 to 6 breaths/min (increase in expiratory time 5 secs). Peak airway pressure was similar at the three respiratory rates (66.8 +/- 8.7 vs. 66.4 +/- 9.5 vs. 67.8 +/- 11.1 cm H2O at 18, 12, and 6 breaths/min, respectively). End-expiratory flow rates (n = 7) were 61.4 +/- 12.6, 38.6 +/- 4.5, and 23.1 +/- 5.8 mL/sec at respiratory rates of 18, 12, and 6 breaths/min, respectively. CONCLUSIONS: Prolongation of expiratory time decreases dynamic hyperinflation in patients with status asthmaticus, as evidenced by a reduction in plateau airway pressure, but the magnitude of this effect is relatively modest when baseline minute ventilation is < or = 10 L/min, because of the low end-expiratory flow rates. Since flow progressively decreases throughout expiration, the reduction in dynamic hyperinflation resulting from a given prolongation of expiratory time will depend on the baseline respiratory rate (i.e., less reduction in dynamic hyperinflation at a lower respiratory rate). Changes in peak airway pressure may not always reflect the changes in dynamic hyperinflation that result from prolongation of expiratory time.

Adult↗
PubMed2003

Panoramic ultrasound of the thyroid.

Panoramic ultrasound is a technical modification of conventional ultrasound that produces images with a large anatomic field of view. Images obtained with this technique display both lobes of the thyroid gland on a single image, and provide an accurate imaging representation of a variety of thyroid disorders. This report describes the use of panoramic ultrasound and presents examples of panoramic ultrasound of the thyroid.

Endocrinology↗
PubMed2003

Overestimation of pulmonary artery occlusion pressure in pulmonary hypertension due to partial occlusion.

OBJECTIVE: To evaluate partial occlusion in patients with pulmonary hypertension with regard to a) the degree to which it leads to overestimation of pulmonary artery occlusion pressure (Ppao) and b) identification of factors that could enhance its recognition. DESIGN: Observational descriptive study. SETTING: Medical intensive care unit. PATIENTS: Fourteen patients with pulmonary hypertension and an increased pulmonary artery diastolic pressure (Ppad) - Ppao gradient (> or = 10 mm Hg). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The Ppao was recorded during partial occlusion (partial Ppao) and after catheter repositioning to obtain a lower, more accurate value (best Ppao). The error due to partial occlusion, defined as the difference between the partial Ppao and the best Ppao, was 13 +/- 5 mm Hg (range, 6-21 mm Hg). The previously widened Ppad - Ppao gradient invariably narrowed during partial occlusion and then increased by 13 +/- 5 mm Hg (range, 5-23) during the best Ppao measurement. There was a moderate correlation between the error due to partial occlusion (partial Ppao - best Ppao) and both the mean pulmonary artery pressure (r =.77, <.01) and the Ppad - Ppao gradient (r =.79, <.01). CONCLUSIONS: Partial occlusion in patients with pulmonary hypertension may lead to significant overestimation of the Ppao and should be suspected when there is a substantial increase in the Ppao without a concomitant increase in the Ppad, as reflected by a marked narrowing of a previously widened Ppad - Ppao gradient.

Catheterization, Swan-Ganz↗
PubMed2002

A pilot project to study the use of ultrasonography for teaching physical examination to medical students.

The purpose of this study was to study the use of ultrasound as an aid to teaching physical examination. Five medical students were given a 1-week course in ultrasound, and were then assigned to clinical rotations to perform ultrasound and physical examinations on patients. Basic ultrasound skills were assessed by having each student scan the same normal model at the conclusion of the first week and at the conclusion of the project. Clinical cases were presented to a preceptor, and the ultrasound images were graded on a five-point scale. At the end of the first week, the mean grade of ultrasound examinations performed on the control model was 3.2, improving to 4.4 at the end of the project. Grading of ultrasound exams performed during the first clinical week averaged 4.1, improving to 4.5 at the end of the project. An exit survey indicated a favorable response to using ultrasound as an educational tool.

Adult↗