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Biomedical subjects

B A Carroll

Publications and source records attributed to B A Carroll.

At least 55 records · Page 3Linked to original sources
PubMed1994

Choroid plexus-ventricular wall separation in fetuses with normal-sized cerebral ventricles at sonography: postnatal outcome.

OBJECTIVE: The choroid plexus typically fills the atrium of the lateral ventricles of the brain in normal fetuses, but separates from the medial ventricular wall with increasing ventriculomegaly. Sonographic depiction of choroid plexus-ventricular wall separation has been associated with a high frequency of unfavorable outcomes in fetuses with mild ventricular dilatation. This separation, however, is also observed in a small subgroup of fetuses with normal ventricular measurements. The objective of this study was to ascertain the prognosis for fetuses when choroid plexus-ventricular wall separation and normal-sized lateral ventricles are seen on antenatal sonograms. MATERIALS AND METHODS: Postnatal follow-up was reviewed for 74 fetuses showing a 3 mm or greater separation between the choroid plexus and the medial ventricular wall and normal-sized (< or = 10 mm) ventricles on antenatal sonograms. Fetuses were divided into normal and abnormal outcome groups, and the data were analyzed to determine if the amount of separation, the ventricular atrial diameter, or the evolution of these findings on follow-up sonograms was predictive of outcome. RESULTS: Fifty-nine patients (80%) had normal outcomes (defined as no congenital anomalies and no significant subsequent medical history apart from usual infant and childhood illnesses) and 15 patients (20%) had abnormal outcomes. The severity of the abnormalities varied widely, ranging from relatively inconsequential, such as isolated polydactyly, to complex congenital malformation syndromes resulting in neonatal death. No consistent pattern of malformation was evident. Although we found a statistically significant difference in the degree of choroid plexus-ventricular wall separation when fetuses were separated into normal and abnormal outcome groups, the range of measurements obtained in these two populations overlapped considerably. Outcomes were normal in all 13 patients in whom the choroid plexus-ventricular wall separation had returned to normal by the time of the last antenatal sonogram. CONCLUSION: A separation of 3 mm or greater between the choroid plexus and the medial ventricular wall is an important finding that is associated with an increased risk of an abnormal outcome even in the subpopulation of fetuses with normal-sized ventricles. Although the outcome will be normal in the majority (80%) of such fetuses, identification of choroid plexus-ventricular wall separation mandates a meticulous examination of fetal anatomy.

Abnormalities, Multiple↗
PubMed1994

Bilateral lower extremity evaluation of deep venous thrombosis with color flow and compression sonography.

Recognition of the accuracy of CUS for diagnosis of DVT has led to increased requests for bilateral lower extremity CUS studies. Compared to unilateral lower limb CUS studies, these examinations are often requested when the clinical suspicion of DVT is less strong. We undertook a 15 month prospective study of bilateral lower extremity CUS examinations to determine the diagnostic yield of positive studies and any correlation with clinical parameters. Eighty-six patients were studied; six patients (7%) had studies positive for acute DVT, and 78 patients (91%) had negative studies. Positive studies did not correlate with clinical parameters except erythema. Concurrently, 23% of unilateral lower limb sonographic studies were positive. Bilateral lower limb CUS is a low yield investigation, which may be indicated in view of the morbidity and mortality associated with DVT and pulmonary embolism.

Constriction↗
PubMed1993

Doppler US assessment of maternal kidneys: analysis of intrarenal resistivity indexes in normal pregnancy and physiologic pelvicaliectasis.

Duplex ultrasound was performed in both kidneys of 156 normotensive pregnant women without suspected renal disease and 25 nonpregnant women of childbearing age to determine if resistivity indexes are different between pregnant and nonpregnant women and to assess whether the "physiologic" pelvicaliectasis of pregnancy causes elevated resistivity indexes. The mean intrarenal resistivity index for pregnant patients was 61.1, and that for nonpregnant women was 61.0. There were no statistically significant differences between the resistivity indexes of pregnant and nonpregnant women, regardless of whether the pregnant patients were considered as a composite group or subdivided by trimester. Twenty-nine right kidneys and four left kidneys in pregnant patients had moderate dilation of the collecting system attributed to physiologic pelvicaliectasis of pregnancy. No statistically significant differences were detected between the resistivity indexes of kidneys with and without pelvicaliectasis. Normal, uncomplicated pregnancy has no significant effect on resistivity indexes obtained in maternal kidneys. Physiologic pelvicaliectasis of pregnancy is likely to be partially a result of obstruction; this too, however, is not reflected by changes in resistivity indexes. An elevated resistivity index during pregnancy should not be attributed to the normal physiologic changes of pregnancy.

Adult↗
PubMed1993

Renal artery stenosis: analysis of Doppler waveform parameters and tardus-parvus pattern.

PURPOSE: The utility of Doppler parameters and waveform contour analysis for diagnosis of renal artery stenosis was studied in a hypertensive population screened for renovascular hypertension. MATERIALS AND METHODS: The Doppler results were compared with those obtained with angiography in a prospective double-blind study involving 118 kidneys in 46 patients with hypertension and 11 potential renal donors with normal blood pressure. Doppler parameters measured in the distal renal artery included systolic acceleration, acceleration time, peak systolic velocity, deceleration in late systole, pulsatility and resistivity indexes, and waveform features in early systole. RESULTS: Angiograms demonstrated 28 stenotic renal arteries. There was no significant difference between stenotic (> 50% diameter narrowing) and nonstenotic renal arteries for any parameters studied. When stenosis was further categorized as moderate (50%-79%) or severe (80%-95%), significant (P < .05) differences for acceleration time and systolic acceleration were found between nonstenotic and severely stenotic arteries. CONCLUSION: Doppler characterization of the tardus-parvus phenomenon in the distal renal artery is not an adequate screening method for detection of renal artery stenosis.

Cohort Studies↗
PubMed1992

Diagnosis of placenta previa during the third trimester: role of transperineal sonography.

Placenta previa can be difficult to diagnose with transabdominal sonography during the third trimester of pregnancy, because of difficulties in imaging the cervix late in pregnancy. Although transperineal sonography offers an additional view of the cervix, its value in the diagnosis of placenta previa has not been studied. Accordingly, we performed transperineal sonography on 164 patients who had had transabdominal scans that had shown placenta previa or had been inconclusive during the third trimester of pregnancy. Transabdominal sonograms had been inconclusive for placenta previa in 157 of these patients because the cervix was not visualized. The remaining seven patients had transabdominal scans that showed placenta previa. Transperineal sonography successfully visualized the internal surface of the cervix in all 164 patients, allowing determination of the presence or absence of placenta previa in all cases. Transperineal sonograms showed absence of placenta previa in 154 patients. At delivery, none of these patients had evidence of placenta previa. Transperineal sonography showed placenta previa in 10 patients. In nine of these patients, placenta previa was confirmed at delivery. The 10th patient did not have clinically significant placenta previa at delivery. Our study shows that transperineal sonography is a valuable technique to complement transabdominal sonography for detection of placenta previa during the third trimester of pregnancy. Use of transperineal sonography should be strongly considered when a definitive diagnosis regarding placenta previa is not possible by transabdominal sonography because the cervix is not visualized. In such cases, transperineal sonography will usually show the internal surface of the cervix without overlying placental tissue, allowing confident exclusion of placenta previa. Occasionally, however, transperineal sonography will show a placenta previa that was not seen with transabdominal sonography.

Cervix Uteri↗
PubMed1992

Femoral artery pseudoaneurysms: value of color Doppler sonography in predicting which ones will thrombose without treatment.

OBJECTIVE: The purpose of this study was to evaluate the Doppler imaging characteristics of femoral artery pseudoaneurysms occurring after cardiac catheterization to determine if color Doppler sonography can be used to predict which pseudoaneurysms would ultimately thrombose spontaneously. MATERIALS AND METHODS: Over a 30-month-period, 24 pseudoaneurysms were studied with serial color Doppler sonography. The color flow, B-mode, and Doppler spectral images and clinical records of patients whose pseudoaneurysms demonstrated spontaneous thrombosis were compared with those of patients who required surgical repair of the pseudoaneurysm. RESULTS: We found no statistically significant differences between the patients whose pseudoaneurysms demonstrated spontaneous thrombosis and those treated surgically in regard to clinical parameters or the volume of the pseudoaneurysm, percentage of flow within the pseudoaneurysm, ratio of forward to reversed flow velocity in the pseudoaneurysm neck, duration of diastolic flow in the pseudoaneurysm neck, or length of pseudoaneurysm neck. However, on color Doppler images, the volume of flow in the lumens of pseudoaneurysms that thrombosed spontaneously (1.8 +/- 3.3 ml) was significantly smaller than the volume of flow in the lumens of those treated surgically (4.4 +/- 3.2, ml, p = .02). CONCLUSION: We conclude that pseudoaneurysms with small volumes of flow in the lumen are more likely to thrombose than are those with large volumes of flow in the lumen. However, color Doppler sonographic characteristics cannot be used to predict subsequent thrombosis.

Aged↗
PubMed1991

Carotid sonography.

Explore the source record for details and available documents.

Arterial Occlusive Diseases↗
PubMed1991

Sonography of the cervix during the third trimester of pregnancy: value of the transperineal approach.

Transabdominal sonography reliably depicts the cervix during the first and second trimesters of pregnancy, but cervical visualization becomes increasingly difficult as the third trimester progresses. To evaluate the possibility of using a perineal approach to bypass the fetus and image the cervix during the third trimester, we used transperineal sonography to image the cervix of 158 third-trimester patients in whom transabdominal visualization was inadequate. The internal os and upper cervix were successfully visualized on transperineal sonograms in all 158 patients, but the region of the external os was obscured by rectal gas in 22 (14%) cases. In some patients in whom the external portion of the cervix was obscured by bowel gas, the problem could be overcome by scanning with the patient in the lateral decubitus position or by rotating the patient. Transperineal sonography is an effective technique for imaging the cervix during the third trimester of pregnancy, allowing cervical visualization in most patients in whom transabdominal sonography of this area is unsuccessful.

Cervix Uteri↗
PubMed1991

Mild fetal renal pelviectasis. Differentiation from hilar vascularity using color Doppler sonography.

Ultrasound often detects a sonolucent region in the hilum of the fetal kidney. Although this sonolucency is usually assumed to represent mild dilatation of the fetal renal collecting system, in pediatric and adult kidneys blood vessel lumina can simulate pelviectasis. We used color Doppler ultrasound to differentiate the fetal renal collecting system from hilar blood vessels and to evaluate how often blood vessels account for the sonolucent region often demonstrated in the renal hilum during antenatal sonography. Twenty-nine kidneys in fetuses with sonolucent hilar regions greater than 2 mm in anteroposterior (AP) dimension were studied with color Doppler ultrasound. Doppler signal was demonstrated in blood vessels adjacent to, but not within, the sonolucent area in the hilum of all 29 kidneys. Based on the absence of color signal in the sonolucent hilar regions studied, with color signal seen in adjacent blood vessels, these regions were felt to represent mildly dilated collecting systems rather than renal vasculature. We conclude that color Doppler ultrasound can differentiate mild pelviectasis from hilar blood vessels in the fetal kidney. Sonolucent areas measuring 2 mm or greater in AP dimension are unlikely to be attributable to renal vasculature.

Female↗
PubMed1991

In utero sonographic appearance of the atrial septum primum and septum secundum.

We present our observation of the sonographic appearance of the septum primum and septum secundum. The septum primum, as the valve of the foramen ovale, has been previously described as a mobile, echogenic line or dot in the left atrium. We believe that these previous descriptions recognize only a small part of a more complex three-dimensional shape. We studied 14 ideal patients, none of whom were referred for suspected fetal cardiac disease. In 1 case the septum primum was seen as a flaplike structure and in 8 cases as a circular structure. In 5 cases it was seen as both flaplike and circular, depending on the scan plane selected. A three-dimensional description of the shape of the septum primum, based on the work of Crelin, is proposed, which explains these two appearances. A better understanding of this anatomical feature may prevent mistaking the septum primum for an abnormality and provide the basis for future advances in fetal echocardiography.

Echocardiography, Doppler↗
PubMed1991

Intra-aortic balloon pumps: an update on radiographic recognition.

Intra-aortic balloon pumps increase myocardial perfusion and decrease cardiac afterload in patients with cardiogenic shock and in high-risk patients scheduled for cardiac surgery. Appropriate positioning of the pump can be confirmed in chest radiographs. Familiarity with available catheters helps the physician to recognize overadvancement of the balloon in the ascending aorta or the aortic arch vessels. Because the balloon is long, its position is juxtarenal in most patients.

Female↗