Jarl Å. Jakobsen

Contrast medium extravasation injury: guidelines for prevention and management.

Abstract. Extravasation of contrast material is a well-recognized complication of contrast-enhanced imaging studies. The management of this complication is contentious; therefore, the Contrast Media Safety Committee of The European Society of Urogenital Radiology decided to review the literature and issue guidelines. A comprehensive literature search was carried out. The resulting report was discussed at the 8th European Symposium on Urogenital Radiology in Genoa, Italy. Automated power injection may result in extravasation of large volumes and may or can lead to severe tissue damage. Infants, young children and unconscious and debilitated patients are particularly at risk of extravasation during contrast media injection. Fortunately, most extravasations result in minimal swelling or erythema, with no long-term sequelae; however, severe skin necrosis and ulceration may occur. Large volumes of high osmolar contrast media are known to induce significant tissue damage. Compartment syndrome may be seen associated with extravasation of large volumes. Conservative management is often adequate, but in serious cases the advice of a plastic surgeon is recommended. Based on the review simple guidelines for prophylaxis and management of contrast medium extravasation injuries are proposed.

Safety of Ultrasound Contrast Agents

The use of ultrasound contrast agents has increased over recent years. The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) decided to review the safety of ultrasound contrast agents in humans and to draw up guidelines. A comprehensive literature search and review was carried out. The resulting report was discussed by the CMSC of ESUR and at the 11th European Symposium on Urogenital Radiology in Santiago de Compostela, Spain, in 2004. Ultrasound contrast agents approved for clinical use are well tolerated, and serious adverse reactions are rarely observed. Adverse events are usually minor (e.g. headache, nausea, altered taste, sensation of heat) and self-resolving. These symptoms may not be related to the ultrasound contrast materials as they have also been observed in placebo–control groups. Intolerance to some components may occur. Generalized allergy-like reactions occur rarely. Ultrasound contrast agents are generally safe. The ultrasound scanning time and the acoustic output should be kept to the lowest level consistent with obtaining diagnostic information. Adverse reactions should be treated symptomatically.

Assessment of renal allograft fibrosis by acoustic radiation force impulse quantification--a pilot study.

Chronic allograft nephropathy characterized by interstitial fibrosis and tubular atrophy is a major cause of renal transplant failure. Acoustic radiation force impulse (ARFI) quantification is a promising noninvasive method for assessing tissue stiffness. We evaluated if the method could reveal renal transplant fibrosis. In a prospective study, 30 adult renal transplant recipients were included. ARFI quantification, given as shear wave velocity (SWV), of the renal cortex was performed by two observers. SWV was compared to grade of fibrosis (0–3) in biopsies. The median SWV was 2.8 m/s (range: 1.6–3.6), 2.6 m/s (range: 1.8–3.5) and 2.5 m/s (range: 1.6–3) for grade 0 (n = 12), 1 (n = 10) and grades 2/3 (n = 8) fibrosis respectively. SWV did not differ significantly in transplants without and with fibrosis (grade 0 vs. grade 1, P = 0.53 and grade 0 vs. grades 2/3, P = 0.11). The mean intraobserver coefficient of variation was 22% for observer 1 and 24% for observer 2. Interobserver agreement, expressed as intraclass correlation coefficient was 0.31 (95% CI: −0.03 to 0.60). This study does not support the use of ARFI quantification to assess low‐grade fibrosis in renal transplants. ARFI quantification in its present stage of development has also high intra‐ and interobserver variation in renal transplants.

Ultrasound contrast agents: clinical applications

Abstract. 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.

Renal Effects of the Non-Ionic Contrast Medium Iopentol after Intravenous Injection in Healthy Volunteers

Renal effects of the new non-ionic contrast medium iopentol in increasing doses were assessed and compared with the effects of physiologic saline. Twenty-four healthy male volunteers, allocated to three dose groups, were given iopentol intravenously in doses of 0.3, 0.6, and 1.2 g I/kg body weight, respectively. The highest dose group was also given physiologic saline separately as a control. The diuresis increased in all groups, most in the highest dose group, and with a concomitant fall of urine osmolality and increase in osmolar clearance. A slight decrease of serum osmolality, creatinine and urea occurred at 3 hours due to hemodilution. The glomerular filtration rate was unaffected by iopentol. The urinary excretion of albumin and β2-microglobulin was unchanged. However, urinary N-acetyl-β-glucosaminidase and alkaline phosphatase increased significantly, most in the highest dose group. All changes were reversible.

Ultrasound contrast agents and their use in urogenital radiology: status and prospects

Abstract. Ultrasound contrast agents (USCAs) for intravenous use are usually microbubbles with a mean diameter less than that of a red blood corpuscle and filled with gas. The USCAs may improve information about tissue characteristics and physiology by enhancing B-mode imaging, all Doppler modalities and by means of contrast-specific imaging, e.g. harmonic and stimulated acoustic imaging. Results from preclinical experiments have been promising, and several of these have been reproduced in clinical studies. This includes improved evaluation of renal vasculature and parenchyma, assessment of vesicoureteral reflux in children, assessment of tubal patency in women, and evaluation of prostate diseases and erectile dysfunction in men. Some of the physical limits of the ultrasound technology, as well as the operator-dependent factors, can probably never be overcome by the use of USCAs; however, the development of USCAs is now about to provide uroradiologists with potentially efficacious products for the benefit of the patient.

RENAL TUBULAR EFFECTS OF DIURETICS AND X-RAY CONTRAST MEDIA : A COMPARATIVE STUDY OF EQUIMOLAR DOSES IN HEALTHY VOLUNTEERS

RATIONALE AND OBJECTIVES.The isotonic nonionic contrast medium iodixanol has been shown to increase urinary enzyme excretion less than the hypertonic contrast medium iopentol. The authors investigated whether this could be caused by different molar loads using enzyme excretion after diuretic administration as a model. METHODS.Matching molar doses of mannitol were given to two groups of 10 healthy volunteers. Furosemide was administered perorally to a third group of 10 persons. Urinary enzyme excretion was sequentially measured, and the results were compared to our previous findings after contrast-media administration. RESULTS.Equimolar doses of mannitol and contrast media (CM) induced similar changes in urine volume and free water clearance. Mannitol and furosemide increased the urinary excretion of N-acetyl-ß-glucosaminidase (NAG) and alkaline phosphatase (ALP) in the period 0 to 4 hours after administration, i.e. during peak diuresis, whereas both CM increased ALP significantly more, their effects still evident at 24 to 48 hours. Iodixanol had no effect on urinary NAG excretion, but iopentol increased NAG more than did mannitol. CONCLUSIONS.The early effect of CM on urinary enzyme excretion can be related, in part, to the increased diuresis, but the late effect apparent at 24 to 48 hours cannot be explained by the osmotic load of the CM.

Volumetric ablation of uterine fibroids using Sonalleve high-intensity focused ultrasound in a 3 Tesla scanner – first clinical assessment

Abstract Introduction: The purpose of this study was to evaluate the feasibility and safety of the Sonalleve high-intensity focused ultrasound (HIFU; Philips Healthcare, Vantaa, Finland) system in ablating uterine fibroids in a 3T magnet. Material and methods: Seven women were included in this study. Treatment was performed according to the manufacturers recommendation. Technical data describing the HIFU procedures were collected. On MR images at baseline, immediately and 30 days after ablation, we evaluated the volumes of the uterus, the dominant fibroid and the ablation zone. The Uterine Fibroid Symptom and Quality of Life (UFS-QOL) questionnaire was used to assess potential clinical response. Results: The procedure was technically feasible in all patients. The median number of sonications performed during each procedure was 20 (range 2–27) per patient, the maximum temperature in all sonication cells was about 68°C. The median procedure time was 156 minutes (range 95–164). The non-perfused volume after treatment ranged from 1 to 27 ml and was unchanged or decreased in all but one patient at 30 days follow-up. There were no major adverse events. Discussion: In our 3T magnet the system was able to heat tissue and induce areas of non-enhancement within uterine fibroids without major complications. Clinical benefit remains to be proven.

Complications Following Ultrasound‐Guided Thoracocentesis

Purpose: To retrospectively register the number and type of complications following ultrasound‐guided thoracocentesis, and to evaluate the need for routine chest X‐ray after the procedure. Material and Methods: Complications were retrospectively registered from the radiological and clinical reports of 371 consecutive patients who had undergone thoracocentesis with a total of 711 procedures. Results: The mean volume evacuated was 823 ml (range 0–3600 ml). Twenty (2.8%) pneumothoraces were found after 711 thoracocenteses, but in no case was chest tube drainage necessary. Hemoptysis occurred in one patient. Conclusion: Ultrasound‐guided thoracocentesis was found to be a safe procedure. Based on these results, no reason was found to introduce an upper limit of the amount of fluid drained in one session. Routine follow‐up chest X‐ray is not justified in the absence of clinical symptoms.

Reducing the risk of iodine-based and MRI contrast media administration: Recommendation for a questionnaire at the time of booking

This paper presents a practical questionnaire to be used when a contrast medium examination is requested. The questionnaire is based on the guidelines from the European Society of Urogenital Radiology. Its aim is to identify patients at increased risk of clinically relevant renal and non-renal adverse reactions to iodine-based and MRI contrast agents. The questionnaire should be completed by the referring physician when the examination is requested.