European Radiology

Grenier, N.; Basseau, F.; Rey, M.; LaGoarde-Segot, L.

doi: 10.1007/s003300100913pmid: 11519536

Combining color and spectral data, Doppler signal provides physiologic information about arterial and venous hemodynamics and anatomic information about vessel walls and diameter. Adequate sampling of Doppler signal is required to avoid pitfalls in interpreting spectral changes or color images. The level of information contained in spectral waveforms is high, compared with color display in terms of velocity profile alterations, as in stenoses, and cyclic changes of systolo-diastolic velocities. Therefore, integration of information from both types of Doppler signal representations is mandatory in clinical practice.

Nilsson, Anders

doi: 10.1007/s003300100914pmid: 11519537

A working knowledge of the most common artefacts in sonography is essential in order to avoid not only misdiagnosis of artefacts as pathology but also failure to detect pathology "in disguise". The basic artefacts affecting all sonography and some of the ones particular to Doppler and contrast ultrasound are discussed.

Correas, Jean-Michel; Bridal, Lori; Lesavre, Amélie; Méjean, Arnaud; Claudon, Michel; Hélénon, Olivier

doi: 10.1007/s003300100940pmid: 11519538

The concept of contrast imaging was introduced to ultrasound almost 30 years ago. The development of ultrasound contrast agents (USCAs), initially slowed by technical limitations, has become more dynamic during the past decade. The ideal USCA should be non-toxic, injectable intravenously, capable of crossing the pulmonary capillary bed after a peripheral injection, and stable enough to achieve enhancement for the duration of the examination. While satisfying cost–benefit requirements, it should provide not only Doppler but also gray-scale enhancement. Already, Doppler examinations are improved by using USCAs when studying deep and small vessels, vessels with low or slow flow, or vessels with a non-optimal insonation angle. Ultrasound contrast agents also enhance detection of flow within abnormal vessels, including tumor vascularization and stenotic vessels, and provide better delineation of ischemic areas. Research is focusing on the development of specific contrast imaging sequences that allow detection of tissue enhancement similar to that obtained with CT or MRI. These sequences take advantage of the non-linear behavior of the microbubbles within the ultrasound field, bringing real-time perfusion imaging for liver, kidney, and the myocardium into reach. New objectives include targeted agents that could further widen USCA applications to specific delivery of active drugs such as anticoagulants or cytotoxic compounds. The combination of new generations of USCAs and new ultrasound image sequences appears to be very promising and currently represents a significant part of ultrasound research.

Jakobsen, Jarl

doi: 10.1007/s003300100964pmid: 11519539

Ultrasound contrast agents (USCA) for intravenous injections are usually gas-filled microbubbles with a mean diameter less than that of a red blood corpuscle. There are only a few products on the market at the time of this writing, but several companies have various agents under development. This paper covers both established USCA on the market, and some new agents under clinical evaluation. The potential of improving ultrasound imaging using USCA depends on several factors. These factors include the pharmacokinetic and pharmacodynamic properties of the products, which determine the effects they have on various ultrasound imaging techniques. Furthermore, the proper clinical application of the agents requires a combination of technical and medical knowledge by the examiner, dedicated equipment, a disease that can be diagnosed or characterised by ultrasound and USCA, and a cooperative patient. Taking into account these factors, USCA can be used for improving the detection, characterisation and follow-up of diseases of several vascular beds and parenchymal organs from head to foot.

Cosgrove, David; Eckersley, Robert; Blomley, Martin; Harvey, Christopher

doi: 10.1007/s003300100985pmid: 11519540

Traditionally, Doppler ultrasound has been used to estimate blood flow as the mean velocity multiplied by the vessel area, but this is subject to significant errors and may be difficult to perform accurately. Microbubbles, developed as contrast agents for ultrasound, were initially envisaged as useful for increasing the intensity of echoes and thus rescuing Doppler studies that were technical failures because of attenuated signals or very slow flow. However, they can act as tracers and, by analogy with isotope techniques, can be used to measure blood flow with transit-time methods which exploit both arterial and venous time–intensity data. An acceptable compromise is to acquire both a tissue intensity curve and one from the feeding artery. The transit of microbubbles across an organ or tissue can be used to estimate haemodynamic alterations, e.g. the arterialisation of the supply to the liver in malignancies and cirrhosis and the delayed arterio-venous transit in the transplant kidney during rejection. The fragility of microbubbles can be turned to advantage by being exploited to create a negative bolus by exposing a tissue slice to a high power beam. The rate of refilling of this slice by circulating microbubbles can then be followed with a low-intensity monitoring beam and the resulting rising exponential curve analysed to extract indices of both the reperfusion rate (the slope) and the fractional vascular volume (the asymptote). The product of these is a measure of true tissue perfusion.

Diederich, S.; Lentschig, M.; Overbeck, T.; Wormanns, D.; Heindel, W.

doi: 10.1007/s003300000787pmid: 11519541

The aim of this study was to compare numbers of pulmonary nodules detected with maximum intensity projections using a slab thickness of 15 mm (MIP 15) and 30 mm (MIP 30) with single image (SI) presentation of chest CT scans. Two readers reviewed MIP 15, MIP 30, and SI presentations of 10-mm (n=8) and 5-mm collimation (n=10) helical CT scans and recorded size, location, and diagnostic confidence (definite, probable) of pulmonary nodules. Readers 1 and 2 recorded more nodules with MIP 15 than with SI: 10-mm collimation, 77/64 and 60/56; 5-mm collimation, 64/60 and 40/36; and more "definite" nodules (10-mm collimation: 68/57 and 51/42; 5-mm collimation: 43/36 and 34/30). MIP 15 also detected more nodules than MIP 30 at 10-mm collimation: 77/72 and 60/50; with no major differences at 5-mm collimation: 64/66 and 40/38; and more "definite" nodules (10-mm collimation: 68/58 and 51/36; 5-mm collimation: 43/39 and 34/29). There were only minor differences between SI and MIP 30. Reading time and image number per study were reduced with MIP presentations by a factor of 1.4–5.3. There were no significant differences in the number of nodules detected with SI, MIP 15, and MIP 30, but MIP presentation reduced reporting time and filming cost when compared with SI reporting. For detection of nodules MIP 15 was slightly superior to MIP 30.

Givica-Pérez, Amparo; Santana-Montesdeoca, José; Díaz-Sánchez, Myriam; Martínez-Lagares, Francisco; Castaneda, Wilfrido

doi: 10.1007/s003300000775pmid: 11519542

Self-administration of metallic mercury through the intravenous route is rare. This event has been reported in psychiatric patients and in suicide attempts. We report a case of successive intravenous self-injections of mercury demonstrated by plain film radiographs and CT scans of the thorax and abdomen.

Kreitner, K.-F.; Kunz, R.; Kalden, P.; Kauczor, H.-U.; Schmitt, S.; Kuroczynski, W.; Mohr-Kahaly, S.; Voigtländer, T.; Krummenauer, F.; Laub, G.; Thelen, M.

doi: 10.1007/s003300100878pmid:

Steinkamp, Hermann; Werk, Michael; Beck, Alexander; Teichgräber, Ulf; Haufe, Mathias; Felix, Roland

doi: 10.1007/s003300000793pmid: 11519544

The aim of this study was to demonstrate the effect of excimer laser and balloon angioplasty of femoral artery stenosis and occlusion after use of a haemostatic puncture closure device. A haemostatic puncture closure device (Angio-Seal) was used in 6000 patients after diagnostic or therapeutic artery catheterisation. In 34 of those patients symptoms of peripheral artery disease occurred. Sixteen of those 34 cases were transferred to our clinic for excimer laser angioplasty. All 16 patients presented with symptoms of acute peripheral artery disease within 1–14 days: superficial femoral artery (SFA) occlusions (4 cases); superficial femoral artery stenosis (3 cases); high-grade stenosis of the common femoral artery (CFA; 3 cases); high-grade stenosis of CFA; SFA and profund femoral artery (PFA; 3 cases); and occlusions of CFA, SFA and PFA (3 cases). Before any procedure was performed, informed consent was given by the patient, which included the use of the Angio-Seal closure device. Every patient who had to undergo recanalisation procedures gave additional informed consent which especially included the usage of the excimer laser for recanalisation. A measurement of the walking distance, ankle–brachial systolic pressure index (ABI) and diagnostic angiography was performed in 13 cases before and immediate after as well as 3 and 6 months after therapeutic percutaneous transluminal laser angioplasty followed by balloon angioplasty (PTLA/PTA). In 3 patients the risks of PTLA/PTA was considered too high; those patients underwent surgical repair. Angiographic and clinical improvement was achieved in 13 of 13 patients. The mean walking distance increased from 81 to >400 m. The average ankle–brachial systolic pressure index (ABI) increased from 0.47 to 0.84. One patient developed a dissection of the SFA, and in 1 case a peripheral embolisation was seen. The PTLA/PTA technique is a successful therapeutic option for patients with femoral artery occlusion or high-grade stenosis after Angio-Seal application.

Azarine, Arshid; Lions, Christophe; Koussa, Mohamed; Beregi, Jean-Paul

doi: 10.1007/s003300000780pmid: 11519545

A 75-year-old man presented with a 5-day history of upper chest discomfort. On auscultation, there was a systolic murmur in the left parasternal area that radiated to the apex. Electrocardiography showed flat T waves in the anterior precordial leads. Chest X ray revealed mediastinal enlargement. Transthoracic echocardiography showed a dilated proximal ascending aorta with moderate aortic regurgitation. A contrast-enhanced helical CT scan, performed to eliminate an aortic dissection, showed a ruptured left coronary sinus of Valsalva aneurysm, confirmed at surgery. This case highlights the fact that helical CT, in patients with suspected aortic dissection, may reveal other pathology that accounts for the clinical presentation.