Current methods in the diagnosis of deep venous thrombosis of the lower limbs

The diagnosis of lower limb deep vein thrombosis requires to use of complementary diagnostic tests. For a long time phlebography has been the only reliable examination and is always regarded as the gold standard by many people. In recent years, non invasive diagnostic modalities have been developed. Most significantly scintigraphy, plethysmography, color Doppler ultrasound and MR imaging. MRI is as reliable as venography but, at the present time, it is time-consuming and far less available than the other modalities. Scintigraphy and plethysmography may be useful but are less accurate and yield a somewhat higher rate of false positive and negative examinations. Color Doppler ultrasound has proved its effectiveness and is currently recommended as the diagnostic modality of choice. Venography is still a significant diagnostic tool for questionable cases or for technically inadequate Doppler ultrasound examinations.     

Strain gauge plethysmographic studies after clipping of the inferior vena cava

Assessment of the hemodynamic effects of the IVC clipping by strain gauge plethysmography provides accurate quantitative data. These correlate very well with the other means of investigation used in the study. Eight patients were controlled in the Vascular Laboratory 9 to 43 months after clipping of the inferior vena cava. They submitted to clinical evaluation, Doppler ultrasound, isotopic venography, abdominal sonography, and strain gauge plethysmography of the lower extremities. This last method provided quantitative data; maximal venous outflow was found to be equivalent in the 8 patients included in the study and in a control group of 20 healthy young volunteers. Strain gauge plethysmography results correlate well with the other means of investigation and demonstrate the efficacy of the dilated venous collateral channels in restoring a normal venous return.     

Complete response of early gastric cancer to uracil and tegafur

The purpose of this study was to explore the value of scrotal ultrasound as a means of evaluating Bancroftian filariasis. Color Doppler ultrasound examinations were performed to look for subclinical hydroceles and motile adult filarial worms (dancing worms) in dilated lymphatics. Sixty-one male subjects from a filariasis-endemic area in Egypt were studied including 19 clinically normal microfilaria (MF) carriers (seven with dancing worms and eight with subclinical hydroceles), 13 MF-negative subjects with positive filarial antigen test results (three with dancing worms and seven with subclinical hydroceles), 22 exposed subjects with no MF and negative antigen test results (no dancing worms, four subclinical hydroceles), and seven subjects with clinical filariasis (no dancing worms, seven hydroceles). Thus, all men tested with clinical filariasis and most clinically normal subjects with either microfilaremia or filarial antigenemia had abnormal ultrasound examination results. Ultrasound findings often changed after therapy with diethylcarbamazine, with disappearance of dancing worms and development of new scrotal calcifications or hydroceles. This study confirms the value of scrotal ultrasound as a means of noninvasively visualizing adult filarial worms and assessing subclinical lymphatic damage in Bancroftian filariasis.     

Prolonged bleeding time: a new clinical manifestation of hepatocellular carcinoma?

Most techniques used so far for the evaluation of diaphragm kinetics are either invasive (electromyography, fluoroscopy), or indirect (respiratory pressures, impedance plethysmography). The aim of this study was to determine whether assessment with ultrasound or fluoroscopy differed, and which technique appeared more suitable in the investigation of quantitative hemidiaphragmatic displacement. Six patients (3 female, 3 male, aged 29 to 40) without respiratory disease were studied during systematic X-Ray chest examination, spirometry, and abdominal sonography. The amplitude of the right diaphragm motion could be measured in all patients with M-mode sonography as well as with fluoroscopy. The vertical ascending motion of the diaphragm measured by M-mode sonography, reached 60% of its maximum amplitude at 50% of inspiratory capacity. There was a significant correlation between the maximum amplitude of diaphragm motion as measured by M-mode sonography (5.8 +/- 0.4 cm; r = 0.89; p = 0.019) or fluoroscopy (5.6 +/- 0.7 cm; r = 0.84; p = 0.036) and the inspiratory capacity (2.73 +/- 0.39 l). M-mode sonography has technical, quantitative and qualitative advantages over fluoroscopy and should be the method of choice in the investigation of suspected diaphragmatic movement disorder. When coupled with other techniques like spirometry, this technique could represent a useful adjunct to functional respiratory studies.     

Renal vascular Doppler imaging: clinical benefits of power mode

Power Doppler ultrasound (US) is a new technology that is superior to conventional color Doppler imaging in the detection of blood flow. Because of its greater sensitivity to flow and reduced angle dependence, power Doppler US demonstrates optimal color filling of renal pedicular vessels and allows improved evaluation of the renal parenchymal microvasculature. Power Doppler US was used as an adjunct to conventional color Doppler imaging in technically challenging cases and to improve evaluation of renal vascular disorders in a series of 916 patients. The primary clinical advantages of using power Doppler US compared with conventional color Doppler imaging include better morphologic appreciation of atherosclerotic changes in the renal artery wall, allowing improved diagnostic performance especially in hemodynamically nonsignificant plaques; ability to differentiate between subocclusive renal artery stenosis and occlusion; increased confidence in the diagnosis of renal vein thrombosis and in the assessment of caval tumor thrombus; and better appreciation of renal cortical perfusion defects. In addition, because of its greater sensitivity to perivascular artifact, power Doppler US has the potential to increase the detection rate for intrarenal arteriovenous fistulas.     

Accuracy of portal and forearm blood flow measurements in the assessment of the portal pressure response to propranolol

BACKGROUND/AIMS: The portal pressure response to propranolol varies significantly in individual patients with cirrhosis. At present, propranolol responders can be identified only by measuring the hepatic venous pressure gradient. The aims of this study were: 1) to investigate whether the noninvasive monitoring of portal blood flow by pulsed Doppler ultrasound and forearm blood flow by strain-gauge plethysmography can predict the hepatic venous pressure gradient response to propranolol in patients with cirrhosis, and 2) to analyze the factors that may influence this response. METHODS: Hemodynamic measurements were undertaken in 80 patients with cirrhosis before and after receiving propranolol (0.15 mg/kg i.v., n = 60) or placebo (n = 20). RESULTS: No changes were observed in the placebo group. Propranolol lowered (p < 0.01) hepatic venous pressure gradient from 17.6 +/- 3.8 to 14.7 +/- 3.8 mmHg, portal blood flow from 1122 +/- 363 to 897 +/- 332 ml/min and forearm blood flow from 7.52 +/- 3.1 to 6.12 +/- 2.3 ml/min%. Changes in hepatic venous pressure gradient were correlated (p < 0.01) with those of portal blood flow (r = 0.82) and forearm blood flow (r = 0.54). The reduction in hepatic venous pressure gradient was > 20% in 23 patients ("responders"). The accuracy of portal Doppler flowmetry in identifying responders was higher than that of forearm plethysmography (88.3 vs. 68.3%, p < 0.05). Multivariate analysis proved that previous variceal bleeding was the only factor independently associated with a lack of response to propranolol (relative risk 3.42, 95% CI 1.5-7.4, p < 0.01). Hepatic venous pressure gradient reduction by propranolol was higher in non-bleeders than in bleeders (-19.9 +/- 9.4 vs. -11.3 +/- 8.6%, p < 0.01). CONCLUSIONS: Portal Doppler ultrasound can be used as a reliable surrogate indicator of the hepatic venous pressure gradient response to acute propranolol administration. In addition, our study indicates that this response is mainly influenced by previous variceal hemorrhage.     

Intraoperative electromyography during thoracolumbar spinal surgery

Intraoperative electromyography can provide useful information regarding lumbosacral nerve root function during thoracolumbar spinal surgery. Free-running electromyography provides continuous feedback regarding the location and potential for surgical injury to the lumbosacral nerve roots within the operative field. Stimulus-evoked electromyography can confirm that transpedicular instrumentation has been positioned correctly within the bony cortex. However, electromyography has a number of potential limitations, which are discussed in this article along with improved methods to increase the overall efficacy of intraoperative electromyography, including: 1) Electromyography is sensitive to blunt lumbosacral nerve root irritation or injury, but may provide misleading results with "clean" nerve root transection. 2) Electromyography must be recorded from muscles belonging to myotomes appropriate for the nerve roots considered at risk from surgery. 3) Electromyography can be effective only with careful monitoring and titration of pharmacologic neuromuscular junction blockade. 4) When transpedicular instrumentation is stimulated, an exposed nerve root should be stimulated directly as a positive control whenever possible. 5) Pedicle holes and screws should be stimulated with single shocks at low-stimulus intensities when pharmacologic neuromuscular blockade is excessive. 6) Chronically compressed nerve roots that have undergone axonotmesis (wallerian degeneration) have higher thresholds for activation from electrical and mechanical stimulation. 7) Hence, whenever axonotmetic nerve root injury is suspected, the stimulus thresholds for transpedicular holes and screws must be specifically compared with those required for the direct activation of the adjacent nerve root (and not published guideline threshold values).     

Fracture of the penis: value of echo-Doppler-color

OBJECTIVE: A case of traumatic rupture of the corpora cavernosa evaluated by color Doppler ultrasonography is presented. METHODS: A 43-year-old male consulted for a large penile hematoma that had presented 16 hours earlier during sexual intercourse. The patient was evaluated by Doppler ultrasound using a 5 Mhz linear probe. The vascular integrity of the penis was demonstrated by color Doppler ultrasonography of the cavernous arteries and penile veins. RESULTS: Disruption at the base of the right corpus cavernosum associated with a small hematoma appeared as adjacent hypoechoic images. The color Doppler ultrasonic evaluation demonstrated the integrity of the arteries and cavernous veins and no pulsation of the hematoma, indicating conservative management. Four months after the trauma, no changes in erectile function or penile deviation have been observed. CONCLUSIONS: Color Doppler ultrasound is a useful diagnostic imaging technique in the assessment and follow-up of penile trauma.     

Variable presentation of cerebrovascular disease in monovular twins

We describe twin girls with bilateral cerebrovascular disease. In one child, a diagnosis of moyamoya disease was made after presentation in infancy with an acute hemiparesis; her asymptomatic sibling was found to have significant bilateral cerebrovascular disease after neuropsychological evaluation and assessment with transcranial Doppler ultrasound. Both subjects showed a discrepancy between verbal and performance IQ and deficits on a test of frontal-lobe function suggesting that these domains should be targeted in cognitive assessment. Family members of subjects with moyamoya are at risk of cerebrovascular disease. Clinical symptoms do not reliably predict disease and those at risk should be offered screening with non-invasive vascular imaging.     

Complete eradication of Aspergillus fumigatus from the lung in an immunocompromised patient by oral itraconazole

Fifty-three deaf subjects with a history of prelingual profound bilateral sensorineural hearing loss, similar language habilitation with hearing aids, and normal velopharyngeal structures underwent a study protocol including speech evaluation, behavioral pure-tone audiometry, videonasopharyngoscopy, multiview videofluoroscopy, and electromyography of the velopharyngeal muscles. Subjects were divided into two groups: the first group included 13 subjects with normal nasal resonance or mild hypernasality (four normals and nine with mild hypernasality); the second group had subjects with severe hypernasality and severe articulation deficits. Pure-tone thresholds, velopharyngeal closure patterns, and electromyographic activity of velopharyngeal muscles were similar for both groups of subjects. However, in subjects with severe hypernasality, despite normal muscle activity as observed by electromyography, velopharyngeal valving activity lacked rhythm and strength during speech. It is concluded that deaf subjects may present a functional disorder of the velopharyngeal sphincter related to absence of auditory regulation during phonation. Visual biofeedback using videonasopharyngoscopy may be useful for treating this disorder.     

Usefulness of Doppler ultrasound in the evaluation of patients with active Crohn's disease

OBJECTIVES: To assess the usefulness of Doppler ultrasound in the evaluation of the vascular changes in the splanchnic circulation and bowel wall described in patients with active Crohn's disease (ACD). DESIGN: We analyzed prospectively with Doppler ultrasound the mean velocity of portal flow, the resistive index (RI) of the superior mesentery artery (SMA) and we looked for vessels within the bowel wall. PATIENTS: 50 patients with ACD and 30 normal individuals. RESULTS: In comparison with normal individuals, patients with ACD showed a statistically significant difference (p < 0.001) in the mean velocity of the portal flow and in the RI of the SMA. In all patients with ACD, vessels could be seen within the bowel wall using the color Doppler ultrasound. CONCLUSION: Doppler ultrasound can be used as a non-invasive method to evaluate the vascular changes which develop in the splanchnic circulation and bowel wall of patients with ACD.     

Use of power Doppler in pediatric neurosonography: a pictorial essay

In pediatric neurosonography, conventional color Doppler imaging has been the primary adjunct to routine gray-scale imaging. Power Doppler sonography is a relatively recent development that does not have the limitations of conventional color Doppler ultrasound. The power Doppler technique measures the energy of moving red blood cells instead of the velocity and direction of flow. Advantages of this technique include increased sensitivity for identifying flow in slow-flow states, more complete evaluation of a vessel, and more accurate evaluation of the course of the vessel. Power Doppler sonography is helpful in evaluation of the neonatal brain in a variety of clinical situations: identifying the exact locations of extraaxial fluid collections, differentiating intraventricular clot from normal choroid plexus, detecting intraventricular hemorrhage, and demonstrating asymmetries in cerebral perfusion. However, in certain difficult cases, use of both conventional color Doppler sonography and power Doppler sonography produces increased diagnostic accuracy because these techniques furnish complementary information.     

Case-control study of prenatal ultrasonography exposure in children with delayed speech

OBJECTIVE: To determine whether there is an association between prenatal ultrasound exposure and delayed speech in children. DESIGN: Case-control study. SETTING: Network of community physicians affiliated with the Primary Care Research Unit, University of Calgary. SUBJECTS: Thirty-four practitioners identified 72 children aged 24 to 100 months who had undergone a formal speech-language evaluation and were found to have delayed speech of unknown cause by a speech-language pathologist. For each case subject the practitioners found two control subjects matched for sex, date of birth, sibling birth order and associated health problems. MAIN OUTCOME MEASURES: Rates of prenatal ultrasound exposure and delayed speech. RESULTS: The children with delayed speech had a higher rate of ultrasound exposure than the control subjects. The findings suggest that a child with delayed speech is about twice as likely as a child without delayed speech to have been exposed to prenatal ultrasound waves (odds ratio 2.8, 95% confidence limit 1.5 to 5.3; p = 0.001). CONCLUSION: An association between prenatal ultrasonography exposure and delayed speech was found. If there is no obvious clinical indication for diagnostic in-utero ultrasonography, physicians might be wise to caution their patients about the vulnerability of the fetus to noxious agents.     

Strain gauge plethysmography and Doppler ultrasound in the measurement of limb blood flow

The maintenance of adequate oxygen delivery (DO2) and tissue uptake (VO2) has become central dogma in the management of the critically ill. However, these parameters are derived using gas tensions measured in mixed venous blood and may not reflect changes in regional blood flow. Therefore, it has become necessary to provide estimates of blood flow to specific organs and to evaluate the most adequate techniques available. In order to define the best means of assessing blood flow to the lower limb noninvasively in normal subjects, measurements of superficial femoral arterial blood flow using Doppler ultrasound (DU) and strain gauge plethysmography (SGP) were compared in 10 normal volunteers at rest and during exercise. To evaluate the effect of strain gauge positioning, results of measurements made under four different combinations of cuff/strain gauge placement were compared in 15 other volunteers. The correlation of the limb blood flow obtained using the two methods at rest and exercise was 0.57 and 0.62 and the limits of agreement (d +/- 2SD) were 0.40 +/- 2.49 and -0.86 +/- 5.22 ml 100 ml-1 tissue min-1 at rest and on exercise, respectively. Results obtained using SGP were more reproducible (Coef. repeat. 0.45 vs. 0.94 ml 100 ml-1 tissue min-1, for SGP and DU, respectively). The various combinations of cuff/strain gauge positioning showed a tendency to over-read when the latter was placed on the thigh, but were not significantly different (P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Venous microembolic signals detected in patients with cerebral sinus thrombosis

BACKGROUND AND PURPOSE: We sought to assess the usefulness of the Doppler technique in the monitoring of microembolic signals in the main venous outflow pathways in superior sagittal sinus thrombosis. METHODS: Transcranial Doppler ultrasound was performed with a range-gated 2-MHz transducer in 6 patients with superior sagittal sinus thrombosis, in 5 subjects with platelet hyperaggregability, and in 20 healthy volunteers. Emboli monitoring was performed mainly in one distal internal jugular vein for 10 to 15 minutes. RESULTS: Three of the six patients (50%) with superior sagittal sinus thrombosis had microemboli. None of the patients with platelet hyperaggregation or healthy volunteers revealed microemboli. CONCLUSIONS: Microemboli can be found in superior sagittal sinus thrombosis by Doppler ultrasound. Their prognostic significance remains to be determined.     

Time domain analysis of embolic signals can be used in place of high-resolution Wigner analysis when classifying gaseous and particulate emboli

The sample-volume length (SVL) of an embolic signal has previously been used to differentiate between gaseous and particulate emboli and has been calculated using high-resolution Wigner analysis. Although successful, this method of analysis is not widely available to other groups using transcranial Doppler ultrasound (TCD) to classify emboli. The SVL of embolic signals can also be calculated using time domain analysis, which is a far simpler method and potentially available to all TCD users. The aim of this study was to compare the SVL of embolic signals calculated using Wigner analysis and time domain analysis to assess whether or not time domain analysis can replace Wigner analysis to classify emboli. In total, 215 particulate and 100 gaseous emboli were recorded onto digital audiotape and analysed off-line. Two SVLs for each embolic signal were calculated by measuring embolic duration and velocity in the time domain and with Wigner analysis. Receiver operator characteristic (ROC) curves were plotted to assess the optimum SVL threshold for each method, and levels of sensitivity and specificity were defined. The optimum SVL threshold using Wigner analysis was 1.28 cm, yielding 93% sensitivity and 97% specificity. Using time domain analysis, the optimum threshold was 1.12 cm, yielding 90% sensitivity and 96% specificity. The methods were compared statistically (chi2) using their optimum thresholds, and were found not to be statistically different for classifying particles p=0.283) or gaseous emboli (p=0.700). This study has shown that the SVL of embolic signals, used to differentiate particulate from gaseous emboli, can be calculated more simply in the time domain, which yields as accurate results as calculating the SVL using Wigner analysis.     

Can trasmitral Doppler E-waves differentiate hypertensive hearts from normal?

Physiological models of transmitral flow predict E-wave contour alteration in response to variation of model parameters (stiffness, relaxation, mass) reflecting the physiology of hypertension. Accordingly, analysis of only the E-wave (rather than the E-to-A ratio) should be able to differentiate between hypertensive subjects and control subjects. Conventional versus model-based image processing methods have never been compared in their ability to differentiate E-waves of hypertensive subjects with respect to age-matched control subjects. Digitally acquired transmitral Doppler flow images were analyzed by an automated model-based image processing method. Model-derived indexes were compared with conventional E-wave indexes in 22 subjects: 11 with hypertension and echocardiographically verified ventricular hypertrophy and 11 age-matched nonhypertensive control subjects. Conventional E-wave indexes included peak E, E, and acceleration and deceleration times. Model-based image processing-derived indexes included acceleration and deceleration times, potential energy index, and damping and kinematic constants. Intergroup comparison yielded lower probability values for model-based compared with conventional indexes. In the subjects studied, Doppler E-wave images analyzed by this automated method (which eliminates the need for hand-digitizing contours or the manual placement of cursors) demonstrate diastolic function alteration secondary to hypertension made discernible by model-based indexes. The method uses the entire E-wave contour, quantitatively differentiates between hypertensive subjects and control subjects, and has potential for automated noninvasive diastolic function evaluation in large patient populations, such as hypertension and other transmitral flow velocity-altering pathophysiological states.     

Macro-EMG and motor unit recruitment threshold: differences between the young and the aged

The relationship between macro-EMG (electromyography) and motor unit recruitment threshold was studied in the first dorsal interosseous (FDI) muscle of normal young and aged subjects. During voluntary isometric contraction, motor unit action potentials (MUAP) were collected by a special quadrifilar electrode and decomposed to each MUAP train (MUAPT) using an EMG signal decomposition technique. Macro-EMG was obtained from the electrode shaft, then triggered and averaged for each MUAPT. A positive linear correlation was observed in both the young and aged subjects. However, the correlation coefficients were significantly lower in the aged individuals than in the young individuals.     

Study of atheromatous stenoses of carotid bifurcations by Doppler ultrasound, spiral angio-MRI, magnetic resonance angiography and comparison with arteriography

PURPOSE: To evaluate Doppler ultrasound (US), Helical CT, Magnetic Resonance (MR) angiography in the detection of carotid bifurcation atherosclerotic disease and comparison with angiography. MATERIALS AND METHODS: After a Doppler US procedure, 56 carotid bifurcations were included (symptomatic stenosis greater than 60% or asymptomatic stenosis greater than 30%). Helical CT, MR angiography and selective arteriography were performed. Stenosis were measured with NASCET criteria. Sensitivity and specificity were calculated and compared to arteriographics findings for each procedure and each grade of stenosis. RESULTS: Helical CT and MR angiography had their best sensitivity in grade 3 (70-99%), 92%, 100% respectively, their specificity was identical (91%). All the occlusions were depicted by the three procedures. CONCLUSION: Association of Doppler US and MR angiography may replace in the future selective angiography in the evaluation of extracranial atherosclerotic disease. Arteriography would be performed only in case of discordance between these two procedures.     

T cell responses to Mycobacterium bovis in red deer, a large animal model for tuberculosis

Uterine morphology assessed by transvaginal ultrasound and the hemodynamics of intratumoral vessels assessed by color Doppler ultrasound were prospectively correlated with the clinical outcome of 25 patients with trophoblastic tumors. Twenty patients were followed without treatment (observation group) and 16 achieved complete local resolution. The four subjects with local persistence were combined with five patients referred from other institutions and received chemotherapy (treatment group). In the observation group both techniques had 100% accuracy in predicting local resolution or local persistence. Persistence was predicted 1-3 weeks before the increase of beta-human chorionic gonadotropin (beta-hCG) levels, whereas resolution was observed up to 8 weeks before the disappearance of beta-hCG. In one patient normal uterine morphology and vascularization in the presence of elevated hCG levels was associated with extrauterine spread. In the treatment group, normal uterine ultrasound morphology and negative color Doppler results had 100% negative predictive value. False-positive results were observed in two cases. We conclude that ultrasound evidence of abnormal uterine morphology or persistent vascularization on color Doppler examination with persistent hCG levels is indicative of local persistence. Normal uterine morphology with negative color Doppler results may be associated with extrauterine spread.