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Biomedical subjects

Henrik S Thomsen

Publications and source records attributed to Henrik S Thomsen.

At least 19 recordsLinked to original sources

European Society of Urogenital Radiology guidelines on contrast media application.

PURPOSE OF REVIEW: The present review covers the European Society of Urogenital Radiology guidelines for safe use of contrast media of importance for referring urologists. RECENT FINDINGS: During the recent years contrast medium-induced nephropathy has become a hot topic. It is of importance to reduce its incidence. First of all, the patients at risk should be identified prior to the administration of a contrast medium, so that appropriate measures can be taken. Before intravenous administration of an iodinated agent but not before gadolinium-based and ultrasound agents, all patients should be questioned about the potential renal dysfunction at the time of referral, and only those who answer affirmative to at least one question should have their serum creatinine level determined. Before intraarterial injection, the serum creatinine should always be measured. In case of an abnormal level, another imaging procedure should be considered. If impossible, hydration should be instituted and administration of nephrotoxic drugs should be stopped. After administration, delayed reactions such as nephrogenic systemic fibrosis, thyreotoxicosis, skin rash, etc. may be seen. Interaction with isotope studies and biochemical analysis occurs too. SUMMARY: The awareness regarding the potential adverse reactions due to contrast media and the necessary precautions to be taken are of utmost importance both for radiologists and referring physicians. This is the only way to reduce their incidence.

Contrast Media↗

European Society of Urogenital Radiology (ESUR) guidelines on the safe use of iodinated contrast media.

Since 1996 the Contrast Media Safety Committee of the European Society of Urogenital Radiology (ESUR) has released 19 guidelines regarding safety in relation to the use of radiographic, ultrasonographic as well as magnetic resonance contrast media. The committee has covered both renal and non-renal adverse events as well as other aspects of contrast media. The present paper is an overview of the work accomplished over the last 10 years regarding radiographic iodinated contrast media.

Contrast Media↗

Nephrogenic systemic fibrosis: suspected causative role of gadodiamide used for contrast-enhanced magnetic resonance imaging.

Nephrogenic systemic fibrosis is a new, rare disease of unknown cause that affects patients with renal failure. Single cases led to the suspicion of a causative role of gadodiamide that is used for magnetic resonance imaging. This study therefore reviewed all of the authors' confirmed cases of nephrogenic systemic fibrosis (n = 13) with respect to clinical characteristics, gadodiamide exposure, and subsequent clinical course. It was found that all had been exposed to gadodiamide before the development of nephrogenic systemic fibrosis. The delay from exposure to first sign of the disease was 2 to 75 d (median 25 d). Odds ratio for acquiring the disease when gadodiamide exposed was 32.5 (95% confidence interval 1.9 to 549.2; P < 0.0001). Seven (54%) patients became severely disabled, and one died 21 mo after exposure. No other exposure/event than gadodiamide that was common to more than a minority of the patients could be identified. These findings indicate that gadodiamide plays a causative role in nephrogenic systemic fibrosis.

Adult↗

Initial clinical experience with oral manganese (CMC-001) for liver MR imaging.

Recently, a new oral liver-specific manganese-based MR agent (CMC-001) has been introduced. This contrast medium is delivered to the liver in high concentrations in the portal vein and very low doses in the hepatic artery, as only small amounts of manganese enter the general circulation. It is taken up by the hepatocytes and excreted in the bile. Our initial experience with the new MR contrast medium in a variety of patients is reported. A total of 20 patients (11 males and 9 females) were studied with MR imaging 2 h after oral ingestion of the contrast agent. Sixteen patients were referred for evaluation of focal liver lesion(s), whereas in the remaining four patients, evaluation of the biliary tract was requested. In the 17 patients without biliary obstruction, there was an increased signal intensity of the liver parenchyma, whereas in the three patients with biliary obstruction, the uptake was delayed. There was excellent visualization of the biliary system on the T1-weighted images in the 16 patients without biliary obstruction referred for evaluation of a focal liver lesion. In seven patients, the uptake was patchy. In patients with focal liver lesions or biliary tract diseases, it is possible to increase the signal intensity of the liver parenchyma after the oral intake of CMC-001. In patients without biliary tract obstruction, the biliary system is easily visualized. Oral manganese seems to be useful in hepatobiliary MRI. Further research is strongly warranted.

Adult↗

Contrast-medium-induced nephropathy: is there a new consensus? A review of published guidelines.

The interest in contrast-medium-induced nephropathy has increased considerably during the last few years. Various guidelines regarding identifying patients at risk and measures to reduce the incidence of this complication have been proposed. The aim of this review was to analyse whether there is some consistency amongst these guidelines. A Medline search for the keyword "contrast medium induced nephropathy" during the period from the beginning of 2003 through the end of September 2005 was carried out. Only papers in English were reviewed. Thirteen guidelines were identified. Inconsistency was observed regarding advise on the prophylactic use of drugs and the isoosmolar dimer to reduce the incidence of contrast-medium-induced nephropathy. Consistency was found in relation to the importance of hydration, cessation of intake of nephrotoxic drugs and administration of the lowest possible dose of contrast medium. No new consensus has been observed in comparison to the European Society for Urogenital Radiology (ESUR) guidelines, which were published in 1999.

Contrast Media↗

Ultrasonography of the metacarpophalangeal and proximal interphalangeal joints in rheumatoid arthritis: a comparison with magnetic resonance imaging, conventional radiography and clinical examination.

Signs of inflammation and destruction in the finger joints are the principal features of rheumatoid arthritis (RA). There are few studies assessing the sensitivity and specificity of ultrasonography in detecting these signs. The objective of the present study was to investigate whether ultrasonography can provide information on signs of inflammation and destruction in RA finger joints that are not available with conventional radiography and clinical examination, and comparable to the information provided by magnetic resonance imaging (MRI). The second to fifth metacarpophalangeal and proximal interphalangeal joints of 40 RA patients and 20 control persons were assessed with ultrasonography, clinical examination, radiography and MRI. With MRI as the reference method, the sensitivity, specificity and accuracy of ultrasonography in detecting bone erosions in the finger joints were 0.59, 0.98 and 0.96, respectively; they were 0.42, 0.99 and 0.95 for radiography. The sensitivity, specificity and accuracy of ultrasonography, with signs of inflammation on T1-weighted MRI sequences as the reference method, were 0.70, 0.78 and 0.76, respectively; they were 0.40, 0.85 and 0.72 for the clinical examination. With MRI as the reference method, ultrasonography had higher sensitivity and accuracy in detecting signs of inflammation and destruction in RA finger joints than did clinical and radiographic examinations, without loss of specificity. This study shows that ultrasonography has the potential to improve assessment of patients with RA.

Adult↗

Effects of iodinated contrast media on blood and endothelium.

The aim of the study was to assess the effects of iodinated contrast media on blood components and endothelium based on experimental and clinical studies and to produce clinically relevant guidelines for reducing thrombotic and hematologic complications following the intravascular use of contrast media. A report was drafted after review of the literature and discussions among the members of the Contrast Media Safety Committee of the European Society of Urogenital Radiology. The final report was produced following discussion at the 12th European Symposium on Urogenital Radiology in Ljubljana, Slovenia (2005). Experimental data indicate that all iodinated contrast media produce an anticoagulant effect and that this effect is greater with ionic contrast media. Several of the in vitro and experimental in vivo studies on haematological effects of contrast media have not been confirmed by clinical studies. Low- or iso-osmolar contrast media should be used for diagnostic and interventional angiographic procedures, including phlebography. Meticulous angiographic technique is the most important factor for reducing the thrombotic complications associated with angiographic procedures. Drugs and interventional devices that decrease the risk of thromboembolic complications during interventional procedures minimize the importance of the effects of contrast media.

Angiography↗

Imaging liver metastases with a new oral manganese-based contrast agent.

RATIONALE AND OBJECTIVES: The purpose of the study was a preliminary evaluation of a new oral, manganese-based, liver-specific contrast medium (CMC-001; CMC Contrast AB, Malmoe, Sweden) for magnetic resonance imaging (MRI) in patients with liver metastases. MATERIALS AND METHODS: The study included 10 consecutive patients with known liver metastases. Patients underwent abdominal MRI as a supplement to routine diagnostics. Patients fasted for at least 10 hours before ingesting CMC-001 (1.6 g manganese chloride tetrahydrate, 1 g alanine, and 1,600 IU vitamin D3 were dissolved in water). MRI took place before and 2 hours after drinking CMC-001. The 1.5-T MRI protocol included two-dimensional T1w sequences to visualize metastases. T2w and diffusion weighted imaging (DWI) sequences were used to identify cysts and blood vessels correspondingly. RESULTS: The intake of CMC-001 caused an increase in the signal intensity of the "healthy" liver tissue, making the internal structure of the liver significantly better visualized. Compared with our routine examinations, MRI showed more metastases in four patients and allowed determining a more precise outline of metastases. CONCLUSION: CMC-001 improves imaging of liver metastases in comparison with computed tomography and with MRI without CMC-001.

Administration, Oral↗

Contrast-induced nephropathy in patients with chronic kidney disease undergoing computed tomography: a double-blind comparison of iodixanol and iopamidol.

BACKGROUND: Based on a single clinical trial, it has been suggested that the contrast agent iodixanol, which is isotonic to human plasma, may be less nephrotoxic than other nonionic contrast agents in renally impaired patients after intra-arterial injection. We compared the effects on renal function of iopamidol-370 injection (796 mOsm/kg) and iodixanol-320 (290 mOsm/kg) in patients with chronic kidney disease undergoing contrast-enhanced multidetector computed tomography (CE-MDCT) examinations using a multicenter, double-blind, randomized, parallel-group design. METHODS: A total of 166 patients with stable moderate-to-severe chronic kidney disease (screening and baseline serum creatinine, SCr, > or =1.5 mg/dL and/or creatinine clearance, CrCl, < or =60 mL/min) who were undergoing CE-MDCT of the liver or peripheral arteries were randomized to receive equi-iodine IV doses (40 gI) of either iopamidol-370 (370 mgI/mL) or iodixanol-320 (320 mgI/mL) at 4 mL/s. SCr and CrCl were obtained at screening, baseline, and at 48-72 +/- 6 hours after dose (mean, 57.4 hours). Contrast-induced nephropathy (CIN) was defined as an absolute increase > or =0.5 mg/dL (44.2 micromol/L) and/or a relative increase in SCr > or =25% from baseline. RESULTS: A total of 153 patients were included in the final analysis (13 patients excluded because of lack of follow-up, hemodialysis to remove contrast, average daily CrCl variation >1% at screening). The 2 study groups were comparable with regard to age, gender distribution, the presence of diabetes, concomitant medications, hydration, and contrast dose. Mean predose SCr was 1.6 +/- 0.4 mg/dL in both groups (P = 0.9). An absolute increase > or =0.5 mg/dL (44.2 micromol/L) in SCr was observed in none of the patients receiving iopamidol-370 and in 2.6% (2/76) of patients receiving iodixanol-320 (95% confidence interval -6.2, 1.0, P = 0.2). A relative increase > or =25% in SCr occurred in 4% (3/77) of patients receiving iopamidol-370 and in 4% (3/76) of the patients receiving iodixanol-320 (95% confidence interval -6.2, 6.1, P = 1.0). CONCLUSION: The rate of CIN was similarly low in risk patients after intravenous administration of iopamidol-370 or iodixanol-320 for CE-MDCT.

Adult↗

Are bone erosions detected by magnetic resonance imaging and ultrasonography true erosions? A comparison with computed tomography in rheumatoid arthritis metacarpophalangeal joints.

The objective of the study was, with multidetector computed tomography (CT) as the reference method, to determine whether bone erosions in rheumatoid arthritis (RA) metacarpophalangeal (MCP) joints detected with magnetic resonance imaging (MRI) and ultrasonography (US), but not with radiography, represent true erosive changes. We included 17 RA patients with at least one, previously detected, radiographically invisible MCP joint MRI erosion, and four healthy control individuals. They all underwent CT, MRI, US and radiography of the 2nd to 5th MCP joints of one hand on the same day. Each imaging modality was evaluated for the presence of bone erosions in each MCP joint quadrant. In total, 336 quadrants were examined. The sensitivity, specificity and accuracy, respectively, for detecting bone erosions (with CT as the reference method) were 19%, 100% and 81% for radiography; 68%, 96% and 89% for MRI; and 42%, 91% and 80% for US. When the 16 quadrants with radiographic erosions were excluded from the analysis, similar values for MRI (65%, 96% and 90%) and US (30%, 92% and 80%) were obtained. CT and MRI detected at least one erosion in all patients but none in control individuals. US detected at least one erosion in 15 patients, however, erosion-like changes were seen on US in all control individuals. Nine patients had no erosions on radiography. In conclusion, with CT as the reference method, MRI and US exhibited high specificities (96% and 91%, respectively) in detecting bone erosions in RA MCP joints, even in the radiographically non-erosive joints (96% and 92%). The moderate sensitivities indicate that even more erosions than are seen on MRI and, particularly, US are present. Radiography exhibited high specificity (100%) but low sensitivity (19%). The present study strongly indicates that bone erosions, detected with MRI and US in RA patients, represent a loss of calcified tissue with cortical destruction, and therefore can be considered true bone erosions.

Adult↗

[Magnetic resonance colonography: a new diagnostic tool].

Magnetic resonance colonography (MR colonography) is a three-dimensional imaging of the colon. Data postprocessing also allows for virtual colonoscopy, depicting the intraluminal morphology. Acquisition and postprocessing of high-resolution images require a state-of the-art modern MR scanner and a workstation. Regarding patient preparation, a bowel cleansing is necessary. The results of cancer screening have shown MR colonography to be superior to the traditional double-contrast barium enema. In inflammatory bowel disease, MR colonography can be used to assess disease activity, including spreading.

Colonic Neoplasms↗

Contrast media: interactions with other drugs and clinical tests.

Many patients with multiple medical problems who are receiving a variety of drugs are investigated with imaging techniques which require intravascular contrast media. The Contrast Media Safety Committee of the European Society of Urogenital Radiology therefore decided to review the literature and to draw up simple guidelines on interactions between contrast media and other drugs. An extensive literature search was carried out and summarized in a report. Based on the available information, simple guidelines have been drawn up. The report and guidelines were discussed at the 11th European Symposium on Urogenital Radiology in Santiago de Compostela. Contrast media may interact with other drugs, and may interfere with isotope studies and biochemical measurements. Awareness of the patient drug history is important to avoid potential hazards. Simple guidelines are presented.

Contrast Media↗

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.

Animals↗

The smallest detectable difference and sensitivity to change of magnetic resonance imaging and radiographic scoring of structural joint damage in rheumatoid arthritis finger, wrist, and toe joints: a comparison of the OMERACT rheumatoid arthritis magnetic resonance imaging score applied to different joint combinations and the Sharp/van der Heijde radiographic score.

OBJECTIVE: To compare 2 magnetic resonance imaging (MRI) approaches and radiographic evaluation according to the Sharp/van der Heijde method with respect to sensitivity to change in joint destruction in patients with rheumatoid arthritis (RA). METHODS: Thirty-five RA patients and 9 healthy controls underwent MRI and radiography on 2 occasions 1 year apart. Conventional radiographs of the hands, wrists, and forefeet were evaluated according to the Sharp/van der Heijde method. MRIs of unilateral wrist and second through fifth metacarpophalangeal (MCP) joints ("few-joints approach") and of bilateral wrist and MCP joints plus unilateral metatarsophalangeal (MTP) joints ("many-joints approach") were assessed for bone erosions according to the scoring system recommended by the OMERACT (Outcome Measures in Rheumatology Clinical Trials) group. The smallest detectable differences (SDDs) of the radiography and MRI scores were computed based on reevaluation of one-third of the study population. RESULTS: Progressive joint destruction, i.e., an increase in score after the followup period, was observed more frequently with the MRI "many-joints approach" (30 subjects) and "few-joints approach" (25 subjects) than with the Sharp/van der Heijde radiographic method (9 subjects) (P < 0.001 by chi-square analysis). No significant difference between the MRI approaches was observed. When only subjects with a change greater than the SDD were considered, progression was revealed with the MRI "many-joints approach," the MRI "few-joints approach," and radiography in 15, 13, and 5 RA subjects, respectively. With both MRI approaches, significantly more subjects with progression were detected than were detected by radiography (P < 0.05). CONCLUSION: MRI, regardless of whether it covers unilateral wrist and MCP joints or bilateral wrist and MCP joints plus unilateral MTP joints, is significantly superior to radiography of the hands, wrists, and forefeet with respect to detection of progressive joint destruction in RA.

Adult↗

Preliminary experience with contrast-enhanced MR angiography in patients with end-stage renal failure.

RATIONALE AND OBJECTIVES: The purpose of this study was to evaluate our preliminary experience with routine contrast-enhanced magnetic resonance angiography (CE-MRA) of the lower limb arteries in patients with end-stage renal failure. MATERIALS AND METHODS: A retrospective analysis was performed on clinical, physiological, and imaging data for 104 patients with end-stage renal failure. Patients were considered to be in end-stage renal failure if they were on renal replacement therapy (peritoneal or hemodialysis) or were being evaluated as part of a pretransplant workup. CE-MRA was carried out on a 1.5-T scanner using a single-injection, three-station moving table technique. RESULTS: Eleven percent of asymptomatic patients with normal ankle/brachial pressure indexes (ABPI) were found to have severe arterial disease on CE-MRA, and in 30% of asymptomatic patients with abnormal ABPI, CE-MRA showed mild or no disease. Moreover two of three symptomatic patients with normal ABPI were shown to have severe disease. Two patients on peritoneal dialysis had to be switched to hemodialysis. No other adverse events were revealed. CONCLUSION: CE-MRA is a useful adjunct to clinical and physiological examination for the evaluation of the lower limb arteries in a group of patients who have a higher-than-average incidence of peripheral vascular disease, yet have previously been severely restricted from traditional angiography because of contrast-medium-induced nephrotoxicity.

Adult↗