European journal of ultrasound : official journal of the European Federation of Societies for Ultrasound in Medicine and Biology最新文献

Case report of a neonate presenting within 1 h of birth with right side scrotal swelling and a dusky skin discoloration thought clinically to be a hydrocele or testicular torsion. Ultrasound examination demonstrated bilateral hydroceles, more prominent on the right, scrotal oedema and a perinephric loculated fluid collection secondary to right adrenal hemorrhage. We review the ultrasound appearance of the normal and haemorrhagic neonatal adrenal and discuss the differential diagnosis of both neonatal adrenal lesions and scrotal swellings. The role and benefits of ultrasound in the primary diagnosis and management of neonatal adrenal hemorrhage is emphasized.

Objective: To define alterations in the blood flow velocities of the ophthalmic artery (OA), central retinal artery (CRA), posterior ciliary artery (PCA) in essential hypertension and to evaluate the effect of a new antihypertensive drug, candesartan which is an angiotensin II receptor antagonist, on the blood flow velocity in hypertensive patients. Methods: Blood flow velocity and resistive index (RI) of the OA, CRA, and PCA were measured in 22 hypertensive patients off medication and 15 controls by color Doppler imaging. After treatment with candesartan, blood flow velocity and RI were again measured in the hypertensive patients. Results: In controls (n=15), the OA had a mean peak systolic flow velocity (PSFV) of 48.1±2.6 cm/s, mean end diastolic flow velocity (EDFV) of 16±1.0 cm/s, and RI of 0.65±0.01; the CRA had a PSFV of 20.8±0.4 cm/s, EDFV of 9.4±0.3 cm/s, and RI of 0.54±0.01; the PCA had a PSFV of 23.6±0.7 cm/s, EDFV of 11.2±0.3 cm/s, and RI of 0.52±0.01. There was a significant decrease in the PSFV and EDFV of the vessels in the medication free hypertensive patients when compared with controls (P<0.05). In the hypertensive patients off medication (n=22), the OA had a PSFV of 29.4±1.2 cm/s, EDFV of 10.4±0.5 cm/s, and RI of 0.71±0.01; the CRA had a PSFV of 15.1±0.6 cm/s, EDFV of 5.4±0.3 cm/s, and RI of 0.65±0.02; the PCA had a PSFV of 17.2±0.6 cm/s, EDFV of 6.7±0.3 cm/s, and RI of 0.61±0.01. RI measured in the OA, CRA, PCA were significantly increased in the hypertensive patients when compared with the controls (P<0.05). In hypertensive patients after medication (n=22), OA had a PSFV of 38.3±2.5 cm/s, EDFV of 12.3±0.7 cm/s, and RI of 0.68±0.01; CRA had a PSFV of 19.2±0.5 cm/s, EDFV of 7.8±0.3 cm/s, and RI of 0.59±0.01; PCA had a PSFV of 20.8±0.8 cm/s, EDFV of 9.2±0.4 cm/s, and RI of 0.56±0.01. There was a significant increase in the blood flow velocities of the OA, CRA, PCA (P<0.05) and significant decrease in the RI values in the treated hypertensive patients when compared with the controls (P<0.05). But blood flow velocities and RI values did not reach the control level. Conclusion: The increase in the RI values and the decrease in the blood flow velocity of extraocular vessels in the hypertensive patients are thought to be caused by increased peripheral resistance in the vessels of the eye and orbit. Although, it increases blood flow velocity and decreases RI significantly, candesartan treatment in the hypertensive patients cannot increase blood flow velocity and decrease RI to the control level.

Objective: To assess the heating caused by selected pulsed Doppler and physiotherapy ultrasound beams by measurements made using thermal test objects. Method: Thermal test objects were used to measure temperature rises in selected ultrasound fields. These were compared with theoretical predictions based on standard exposure measurements. A separate thermocouple was used to measure heating at the transducer surface. Results: Temperature rises of up to 6 °C were measured for Doppler fields using a thermal test object. The attenuation-corrected temperature rises that were measured generally agreed with calculated Thermal Indices. Temperature rises of up to 2 °C were observed for physiotherapy ultrasound fields in pulsed operation. Conclusion: Significant overlap between the measured temperature rises of selected pulsed Doppler and physiotherapy ultrasound fields was observed.

The possibilities and the limits of transabdominal ultrasonography (US) in the diagnosis of bilio-pancreatic diseases are reviewed here in the light of the last 10 years’ research. US remains the method of choice for the diagnosis of gallstones and is generally accepted as an initial imaging technique in gallstone complications, such as acute cholecystitis. Moreover the method can be useful for the detection of the biliary complications after laparoscopic cholecystectomy and after liver transplantation. US is still considered the first diagnostic procedure when stones are suspected in the common bile duct. The use of color Doppler can provide a differential diagnosis of gallbladder cancer with respect to other benign inflammatory or polypoid lesions. Color Doppler US allows to detect vascular complications of acute pancreatitis such as pseudoaneurysms. US is still considered useful for the initial screening of the pancreatic cancer. However, for staging other imaging techniques must be employed. With US useful informations are obtained in the diagnosis of cystic tumors of the pancreas and of pancretic metastases. US is generally of little use for the diagnosis of endocrine tumors.

Objective: Among other factors, the cerebral blood flow (CBF) is regulated in accordance to the arterial CO₂ tension and the cortical activity. The CO₂ test is commonly used to measure the vascular reserve capacity. Most functional imaging studies rely on the activity-flow coupling (AFC). We aimed to combine both challenges in order to increase the insight into mechanisms of CBF regulation. Methods: Fifteen healthy students underwent a functional transcranial Doppler test using a visual stimulation paradigm: firstly under normocapnia and secondly under conditions of hypercapnia. Hypercapnia was induced by breathing a carbogene gas mixture of 5% CO₂ and 95% O₂. The entire time course of flow velocity adaptation in the posterior cerebral artery (PCA) was analyzed mathematically using a control system approach. Results: Resting CBF velocities increased by nearly 26% under conditions of hypercapnia, whereas the slight increase in arterial blood pressure (ABP) and the decrease in the Pourcelot–Pulsatility index (PI) were statistically not significant. From the control system parameters which were time delay, rate time, gain, attenuation and natural frequency, only the parameter rate time, indicative for the initial steepness of flow velocity increase, showed a statistically significant decrease, consistently for the peak systolic and enddiastolic flow velocity data. As concluded from the unchanged gain parameter the absolute amount of blood flow evoked by the same visual stimulus increased also by 26%. Conclusion: Evaluated by Doppler measurements hypercapnia seems to influence the AFC in two ways: It decreases the steepness of the initial increase in blood flow velocity and enhances the absolute amount of blood flow evoked by the same stimulus.

Purpose: To assess the diagnostic value of Levovist in the ultrasound imaging of visceral arteries in patients with clinical symptoms of abdominal angina, before and after percutaneous transluminal angioplasty (PTA). Material and method: During a 12-month period (2000/2001) five patients with visceral arterial stenoses had ultrasound examinations and a subsequent PTA procedure. Indications for ultrasound examination were abdominal angina symptoms persisting for 3–5 years, (postprandial abdominal pain, diarrhea, and vomiting). In all patients ultrasound examinations were performed using color and spectral Doppler before and after Levovist injections. Color Doppler images and maximum blood flow velocity in stenosed visceral arteries were assessed. Patients underwent control Doppler examinations with Levovist injections to assess the effect of PTA. Results: In three patients conventional Doppler examination did not allow proper evaluation of visceral arteries, because of weak color and spectral Doppler signal and in two remaining patients visceral arteries were not visualized at all. In all five patients strong enhancement of color and spectral Doppler signal was observed after Levovist administration. In all these cases a hemodynamically significant stenosis was diagnosed: coeliac trunk-2 and superior mesenteric artery-3. PTA was performed successfully in these patients. In one of them ultrasound examination done before Levovist injection allowed good visualization of treated SMA and showed good PTA result. In the remaining four patients Doppler examination with the use of Levovist demonstrated visceral arteries well and confirmed successful PTA procedures. Conclusions: The use of Levovist makes the diagnostic efficiency of Doppler examinations much higher. In most cases it allows an unequivocal diagnosis of visceral artery stenosis in patients with abdominal angina symptoms. The Doppler examination with the use of Levovist is the method of choice in follow-up after PTA.

This review gives a summary on current ultrasound contrast agents and their composition. Methods of brain imaging using UCA, like harmonic imaging and acoustic emission, are also described. Besides contrast-enhanced conventional color duplexsonography of the extracranial brain supplying arteries, transcranial contrast investigation of the basal cerebral arteries and visualization of cerebral microcirculation are also discussed in this paper. Another main topic are the interactions between UCA, human tissue and the ultrasound system.

Using B-mode transcranial sonography (TCS), it is possible to image the brain parenchyma through the intact skull with conventional low-frequency probes. Several brain disorders can be depicted by TCS such as bleedings, brain tumors, or enlargement of the ventricular system. More recently there is evidence that TCS findings can complement information from other neuroimaging techniques in neurodegenerative disorders leading to new insights and pathophysiological concepts.

Re-opening of the occluded artery is the primary therapeutic goal in hyper-acute ischemic stroke. Systemic treatment with IV rt-PA has been shown to be beneficial at least in a 3 h ‘door to needle’ window and is approved within that interval in many countries. Trials of thrombolytic therapy with rt-PA demonstrated a small, but significant improvement in neurological outcome in selected patients. As recently shown, intra-arterial application of rt-PA is effective and opens the therapeutical window to 6 h, but requires invasive intra-arterial angiographic intervention in a high number of patients, who do not finally achieve thrombolysis. Ultrasound (US) is known to have several biological effects depending on the emission characteristics. At higher energy levels US alone has a thrombolytic effect. That effect is already used for clinical purposes in interventional therapy using US catheters. Recently, there is growing evidence that US at lower energy levels (<2 W/cm²) facilitates enzymatic mediated thrombolysis, most probably by breaking molecular linkages of fibrin polymers and therefore, increasing the working surface for the thrombolytic drug. Different in-vitro and in-vivo experiments have shown increased clot lysis as well as accelerated recanalization of occluded peripheral, coronary vessels and most recently also intracerebral arteries. Sonothrombolysis at low energy levels, however, is of great interest because of the low risk for collateral tissue damage, enabling external insonation without the need for local catheterization. Whereas little or no attenuation of US can be expected through skin and chest, intensity will be significantly attenuated if penetration of bones, particularly the skull, is required. That effect, however, is frequency dependent. Whereas >90% of intracerebral US intensity is lost (of the output power) in frequencies currently used for diagnostic purposes (mostly 2 MHz and up), that ratio is nearly reversed in the lower KHz range (<300 kHz). US at these low frequencies, however, is efficient for accelerating enzymatic thrombolysis in-vitro as well as in vivo within a wide range of intensities, from 0.5 W/cm² (MI∼0.3) to several W/cm². Since the emitted US beam widens with decreasing frequency, low-frequency US can insonate the entire intracerebral vasculature. That may overcome the limitation of US in the MHz range being restricted to insonation of the MCA mainstem. There are no reports in the preclinical literature about intracerebral bleeding or relevant cerebral cellular damage (either signs of necrosis or apoptosis) for US energy levels up to 1 W/cm². Moreover, recent investigations showed no break-down of the blood brain barrier. Safety of US exposure of the brain for therapeutic purposes has to address heating. Heating depends critically on the characteristics of the US. The most significant heating of the brain tissue itself is >1  ×