Biomedical subjects
Publications and source records attributed to B A Carroll.
One hundred twenty infants ranging in weight from 600 to 4,000 grams were entered into a prospective sonographic study to establish normal renal growth parameters. Renal cortical echogenicity was demonstrated to decrease with increasing infant weight. Observations on the use of Doppler analysis for assessing renal vascular flow are presented.
Ultrasound has been shown to be a reliable and valuable tool in the diagnosis of scrotal abnormalities. In this article, a comprehensive discussion of scrotal abnormalities and their ultrasonographic appearance is presented, oriented toward common clinical presentations, and the present uses and indications of scrotal ultrasound are enumerated.
A prospective sonographic study of 21 patients with suspected renal colic was undertaken to detect the presence or absence of urinary tract calculi. The presence of calculi was diagnosed sonographically by visualization of the calculus and/or unilateral hydronephrosis in all 18 cases in which presence of a calculus was subsequently proved by surgery, spontaneous passage and recovery, or intravenous urography. In the two cases in which the sonographic examination demonstrated neither calculi nor unilateral obstruction, further evaluation confirmed the absence of calculi. There was one false-positive examination in which unilateral hydronephrosis was detected secondary to a retroperitoneal tumor. There were no false-negative examinations. The results of this study support the use of ultrasound in the initial evaluation of renal colic.
Ultrasonic waveforms backscattered from human spleens in vivo were recorded for 10 normal subjects and 21 patients with Hodgkin lymphoma prior to staging laparotomy. A measure of the structure of splenic tissue, the "mean scatterer spacing" was calculated for each subject from the recorded data. Comparison of these measurements with the results of staging laparotomy indicated that spleens involved with lymphoma are generally characterized by increased scatterer spacing compared with normal splenic tissue. The observed histologic differences between normal and lymphomatous spleens appear to account for the measured differences in tissue structure.
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Monitoring fetal growth and detecting intrauterine growth retardation comprise a large percentage of the reasons for ultrasound examinations. Detecting intrauterine growth retardation can significantly reduce perinatal mortality and is facilitated by calculations of numerous fetal measurements.
Ninety-two consecutive neonates were prospectively evaluated with real-time ultrasound to assess the frequency of adrenal visualization. The right gland was identified in 97% of neonates and the left in 83%. Criteria for normal length and width are presented. The characteristic sonographic appearance of the neonatal adrenal is described and correlated with histologic data. Ultrasound is the examination of choice for evaluating the neonatal adrenal gland.
Gas within embolized, uninfected tumors has been ascribed to either carbon dioxide produced through anaerobic reticulocyte metabolism or oxygen release from oxyhemoglobin. An alternative hypothesis explaining the presence of gas within embolized, uninfected tumors, namely, that gas is introduced during the embolization procedure, is presented. Experimental results corroborating this hypothesis are also described.
Duplex ultrasound examination of the carotid arteries using high-resolution realtime imaging and pulsed Doppler flow measurements with velocity spectrum analysis was performed on a series of 50 consecutive patients (100 vessels), and findings were compared with findings of conventional carotid arteriography. The criteria for an abnormal duplex examination included: a velocity ratio of 1.5 or more (ratio of the maximum internal carotid artery [ICA] flow velocity to the maximum common carotid artery flow velocity); turbulence, as indicated by an ICA velocity spectral width of 40 cm per second or more; visible plaque that produced an ICA stenosis of 50% or more; a maximum ICA velocity of 100 cm per second or more; and inability to detect ICA flow. A flow-limiting stenosis was defined arteriographically as a 50% or greater stenosis of the diameter of the arterial lumen. The velocity ratio was the best single duplex criterion, with an overall accuracy of 88%. The sensitivity or specificity of the duplex examination was as high as 97%, depending on the number of duplex criteria that were abnormal.
Real-time sonography provides a noninvasive method of determining the level of obstruction in patients with imperforate anus. The authors describe one technique for evaluating this anomaly which was employed in 6 neonates. A pouch-perineum distance of less than 1.5 cm is consistent with a low lesion, while a pouch that terminates above the base of the bladder is indicative of a high lesion.
High-frequency real-time sonography has enhanced accuracy in the diagnosis of scrotal abnormalities. Results of 48 scrotal scans of 92 testes are presented. There were 22 testicular lesions, nine seminomas, four embryonal cell carcinomas, one case of metastatic prostatic carcinoma, one benign "keratin cyst," three testicular infarcts, three atrophied testes, and one case of testicular torsion. Hypoechoic tumors and infarcts have a similar appearance. Extratesticular abnormalities included spermatoceles, varicoceles, epididymitis, hydroceles, and a scrotal hematoma. Sonography accurately distinguished between testicular and extratesticular masses in all cases in this series and pathologic correlations were obtained for all testicular masses. Simultaneous real-time contact scanning and palpation facilitated accurate diagnosis.
Gallbladder wall thickening (3 mm or greater) has been described as a sign of acute or chronic inflammatory disease of the gallbladder. However, gallbladder wall thickening is a nonspecific finding in contracted, postprandial gallbladders and in cases of hypoproteinemia, elevated portal venous pressure, congestive heart failure, multiple myeloma, and hepatitis. This report describes the case of a patient who had a markedly thickened gallbladder wall secondary to focal obstruction of gallbladder lymphatic drainage by malignant lymphoma in the portal lymph nodes.
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The physics of pulsed Doppler techniques have been recently applied to clinical evaluation of superficial blood vessels and the flow within them. Essential physical principles of pulsed Doppler ultrasound are presented, including spectrum analysis and flow measurements. Duplex instrumentation combining high-resolution real-time imaging and a pulsed-Doppler system is described. Indications for duplex carotid sonography are outlined. Clinical applications are discussed and examples of normal and pathologic states are shown. Finally, the role of duplex sonography in the evaluation of carotid vascular disease is compared to traditional arteriographic and contemporary digital subtraction angiographic methods.
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Pilot studies have shown that gelatin encapsulated microbubbles (GEM) are readily demonstrable ultrasonic contrast agents. GEM injected into hepatic and renal blood vessels resulted in increased echogenicity of the parenchyma in normal rabbits. VS carcinoma implanted in the rabbit liver and kidney showed significantly different echogenicity from that of normal parenchyma following GEM injection. Echogenic bubbles were delivered to different regions by varying the size of GEM.
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