[Gadolinium deposition-"gadolinium deposition disease"]. / Gadoliniumablagerungen ­ Morbus Gadolinium.

Gadolinium (Gd)-based contrast agents have been routinely used worldwide in diagnostic MRI since 1988. All routinely applied contrast agents for clinical use were considered extremely safe with regard to tolerance, adverse effects and diagnostic efficacy and when used at Food and Drug Administration-approved doses. With the identification of Gd-associated disorders, namely nephrogenic systemic fibrosis and adverse reactions, and in the longer term Gd-retention in the brain, this view changed and led to the withdrawal or restriction of approval of linear Gd chelates in Europe. Even though Gd deposition in different human body areas was described very early, recently published literature of intracerebral accumulation of contrast agents as well as deposition in bone have created surprising attention. Not only was the fact of Gd deposition in the body well known for many years, but there is currently no clinical evidence of patient symptoms and no resulting health issues of patients have been observed yet. The expression "gadolinium deposition disease" has been termed by active patient advocacy groups with an online presence with reports of individual members stating a broad spectrum of disorders yielding a large symptom complex after administration of Gd-based contrast agents without evidence of any pre-existing or otherwise underlying disease process which could explain the mentioned disorder.

[New developements in endovascular infrarenal aortic aneurysm treatment]. / Aktuelle Neuerungen bei der endovaskulären Versorgung infrarenaler Aortenaneurysmen.

CLINICAL/METHODICAL ISSUE: New technical developments in endovascular aortic repair (EVAR) have broadened the range of patients eligible for minimally invasive aneurysm treatment. Optimization of delivery sheaths and catheters by considerable downsizing of diameters, increase of pushability and stability combined with flexibility are important parameters. PERFORMANCE: Especially patients characterized by small and tortuous iliac access vessels can nowadays be treated by EVAR. Ease and effectiveness of applicability guarantee safety and quality improvement, which results in better treatment of patients. Progress in stent-graft design with integrated options for repositioning, active positioning and aneurysm sealing facilitate treatment of angulated vessel segments or hitherto unsuitable sealing zones. PRACTICAL RECOMMENDATIONS: Interventionalists have to be familiar with all available stent-graft materials and techniques. Profound knowledge helps to choose the best material for a patient's individual anatomy, confident application and long-term satisfactory results.

[Conventional radiological diagnosis of benign none neoplasms]. / Konventionell-radiologische Diagnose von gutartigen Knochentumoren.

BACKGROUND: Benign bone tumors are of special clinical importance because they might be confused with malignant bone tumors. OBJECTIVES: The aim of this article it to present the characteristics of benign bone tumors. The focus is orientated towards conventional x­ray as the essential pillar for primary diagnosis. Consequently, the description of signal intensities of benign bone tumors in magnetic resonance images or less helpful clues like male-female ratios are deliberately omitted. RESULTS: The classification of bone tumors introduced by Lodwick allows the identification of benign growth patterns. Growth patterns will not help, for example, in case of dedifferentiation of benign chondroid tumors towards chondrosarcomas. Therefore, each diagnosis has to incorporate the patient's clinical scenario. Furthermore, benign bone tumors might also cause aggressive growth patterns. Tumors classified as Lodwick Ic or higher should not be automatically regarded as malignant. Naturally, further clarification is mandatory for these tumors. CONCLUSIONS: Differentiation between definitely benign bone tumors and those which need further work up is a critical diagnostic step. In the majority of cases, this is possible based on the appearance in conventional x­ray images. In case of possibly malignant lesions, both the patient's symptoms and the x­ray morphology have to be considered by orthopedic surgeons, pathologists, and radiologists to determine the optimal diagnostic strategy.

Experimental scoring systems for macroscopic articular cartilage repair correlate with the MOCART score assessed by a high-field MRI at 9.4 T--comparative evaluation of five macroscopic scoring systems in a large animal cartilage defect model.

OBJECTIVE: To develop a new macroscopic scoring system which allows for an overall judgment of experimental articular cartilage repair and compare it with four existing scoring systems and high-field magnetic resonance imaging (MRI). METHODS: A new macroscopic scoring system was developed to assess the repair of cartilage defects. Cartilage repair was graded by three observers with different experience in cartilage research at 2-3 time points and compared with the protocol A of the international cartilage repair society (ICRS) cartilage repair assessment score, the Oswestry arthroscopy score, and macroscopic grading systems designed by Jung and O'Driscoll. Parameters were correlated with the two-dimensional (2D) magnetic resonance observation of cartilage repair tissue (MOCART) score based on a 9.4 T MRI as an external reference standard. RESULTS: All macroscopic scores exhibited high intra- and interobserver reliability and high internal correlation. The newly developed macroscopic scoring system had the highest intraobserver [0.866 ≤ intraclass correlation (ICC) ≤ 0.895] and the highest interobserver reliability (ICC = 0.905) for "total points". Here, Cronbach's alpha indicated good homogeneity and functioning of the items (mean = 0.782). "Total points" of the 2D MOCART score correlated with all macroscopic scores (all P < 0.0001). The newly developed macroscopic scoring system yielded the highest correlation for the MRI parameter "defect fill" (rho = 0.765; all P < 0.0001). CONCLUSIONS: "Total points" and "defect fill", two clinically relevant indicators of cartilage repair, can be reliably and directly assessed by macroscopic evaluation, using either system. These data support the use of macroscopic assessment to precisely judge cartilage repair in preclinical large animal models.

Conservative treatment of gastric perforation after microwave ablation of a hepatocellular carcinoma: Case report.

RATIONALE: Microwave ablation (MWA) has been proven to be an efficient and safe method for local tumor control of liver tumors. Reported complications are rare, but include liver abscess, hematoma, pleural effusion, and occasional thermal injury of the adjacent colon. Intestinal perforation usually requires immediate surgical treatment to prevent generalized peritonitis and sepsis. PATIENT CONCERNS AND DIAGNOSIS: Herein, we describe a case of gastric perforation following percutaneous MWA for hepatocellular carcinoma as a bridging therapy prior to liver transplantation. INTERVENTIONS: Due to the clinical condition of the patient, conservative treatment was considered sufficient. Nine months after MWA, successful liver transplantation followed. Intraoperative findings revealed a scar in the gastric wall with tight adhesions to the liver, requiring adhesiolysis and subsequent suturing. Postoperative recovery was uneventful. OUTCOME: At present, the patient is doing well. No further gastrointestinal events occurred. LESSON: To our knowledge, this is the first report of such a complication occurring after MWA. Moreover, in this case, the gastric perforation could be treated conservatively.

[Hemodialysis fistulas: possibilities of vascular ultrasound]. / Dialyseshunt : Möglichkeiten der Gefässsonographie.

Vascular ultrasound is an established technique in shunt diagnostics for hemodialysis fistulas that allows non-invasive diagnosis of vascular morphology and hemodynamics. Early detection of shunt stenoses in hemodialysis fistulas or thrombotic occlusions facilitates an interventional decision. High occlusion rates of up to 45% within 1 year in hemodialysis fistulas due to reduced flow volume justify follow up with vascular ultrasound examination. The use of high resolution transducers in vascular ultrasound enables complications, such as stenoses and occlusions to be recognized early therefore allowing preemptive therapy. In the present review the examination technique and strategy, the most important complications and treatment options will be discussed.

Prospective study of bone mineral density and metabolism in patients with chronic hepatitis C during pegylated interferon alpha and ribavirin therapy.

The importance of osteoporosis as a complication of end-stage liver disease is well known. However, significant osteopenia may occur in earlier stages of chronic hepatitis C (CHC). Furthermore, antiviral therapy may influence bone metabolism. Thirty patients with CHC genotype 1 infection and without established cirrhosis were treated with peginterferon-alfa and ribavirin. Dual-energy x-ray absorptiometry was performed at baseline, after 48 weeks of therapy, and by the end of a 24-week follow-up period. Bone mineral density (BMD), T-scores, and Z-scores were assessed. Serum C-terminal propeptide of type I collagen (CICP) and osteocalcin levels were measured. Thirteen patients had osteopenia (43%) and osteoporosis was present in four patients (13%). Antiviral therapy led to significant on-treatment increases of lumbar spine and hip BMD (P < or = 0.05) as well as T-scores (P < or = 0.05) and Z-scores (P < or = 0.01) irrespective of subsequent treatment response. Further analyses showed that in patients with sustained virological response (n = 19) most parameters remained highly above baseline values by the end of the 24-week follow-up period, while patients with virological relapse (n = 11) had decreases of BMD, T-scores and Z-scores thereafter that did not differ from baseline. Serum CICP and osteocalcin levels decreased during therapy. Osteocalcin levels remained below baseline in sustained responder, but showed an increase in relapsers by the end of the 24-week follow-up (P < or = 0.05). Osteopenia is detectable in a substantial proportion of CHC patients without established cirrhosis. Antiviral therapy leads to an on-treatment increase of BMD, which may last in those patients who achieve a sustained virological response.

Reproductive interference between the common ground-hopper Tetrix undulata and the slender ground-hopper Tetrix subulata (Orthoptera, Tetrigidae).

The coexistence of closely related species is often hampered by resource competition or reproductive interference (interspecific sexual interactions). Species utilising similar signal channels might face substantial problems when they co-occur. It has, therefore, been suggested that reinforcement might drive signal evolution in narrow suture zones of secondary contact. However, species with large overlapping ranges are usually not believed to interact sexually. The Slender Ground-hopper, Tetrix subulata, and the Common Ground-hopper, Tetrix undulata (Orthoptera: Tetrigidae) are sister species, which occur sympatrically in large parts of western and Central Europe, but rarely share the same habitat. It has been hypothesized that reproductive interference might account for their missing coexistence. Here, we test experimentally whether these two species interact sexually. Our results suggest an incomplete premating isolation of these ground-hoppers, as we recorded heterospecific courtship, mating attempts and mating. The number of conspecific copulations and mating attempts of T. subulata decreased substantially in the presence of T. undulata, whereas the latter species was not negatively affected. Males of both species preferred to approach females of T. undulata, whereas females of both species did not discriminate against heterospecific males. Further studies on the reproductive success are needed to clarify whether reproductive interference might influence habitat partitioning between these species.

Transarterial embolization (TAE) as add-on to percutaneous radiofrequency ablation (RFA) for the treatment of renal tumors: Review of the literature, overview of state-of-the-art embolization materials and further perspective of advanced image-guided tumor ablation.

Percutaneous radiofrequency ablation (RFA) for the treatment of stage I renal cell carcinoma has recently gained significant attention as the now available long-term and controlled data demonstrate that RFA can result in disease-free and cancer-specific survival comparable with partial and/or radical nephrectomy. In the non-controlled single center trials, however, the rates of treatment failure vary. Operator experience and ablation technique may explain some of the different outcomes. In the controlled trials, a major limitation is the lack of adequate randomization. In case reports, original series and overview articles, transarterial embolization (TAE) before percutaneous RFA was promising to increase tumor control and to reduce complications. The purpose of this study was to systematically review the literature on TAE as add-on to percutaneous RFA for renal tumors. Specific data regarding technique, tumor and patient characteristics as well as technical, clinical and oncologic outcomes have been analyzed. Additionally, an overview of state-of-the-art embolization materials and the radiological perspective of advanced image-guided tumor ablation (TA) will be discussed. In conclusion, TAE as add-on to percutaneous RFA is feasible and very effective and safe for the treatment of T1a tumors in difficult locations and T1b tumors. Advanced radiological techniques and technologies such as microwave ablation, innovative embolization materials and software-based solutions are now available, or will be available in the near future, to reduce the limitations of bland RFA. Clinical implementation is extremely important for performing image-guided TA as a highly standardized effective procedure even in the most challenging cases of localized renal tumors.

Impact of ECG gating in contrast-enhanced MR angiography for the assessment of the pulmonary veins and the left atrium anatomy.

PURPOSE: Implementation of ECG gating in contrast-enhanced MR angiography (ceMRA) for improved visualization of the pulmonary veins, the left atrium, and the thoracic vessels. MATERIALS AND METHODS: CeMRA was performed on twelve patients with a history of recurrent atrial fibrillation for the purpose of an intra-individual comparison with and without ECG gating on a 1.5 Tesla MR system (Gyroscan Intera, Philips Medical Systems, Best, NL). Objective image quality parameters such as the signal-to-noise ratio (SNR) of the blood and the contrast-to-noise ratio (CNR) between the blood and myocardium or lung parenchyma were analyzed. The contour sharpness of the pulmonary veins, left atrium, ascending aorta, and pulmonary trunk was also measured. In addition, the artifact level was subjectively assessed by two observers blinded with respect to the sequence parameters. Statistically significant differences (p < 0.05) between the procedures were analyzed using the Wilcoxon test and Pearson Chi-square test. RESULTS: The use of ECG gating in ceMRA significantly reduced artifacts caused by cardiac motion and vessel pulsation. This in turn lead to a significant increase in the contour sharpness of the left atrium and the thoracic vessels. In addition, higher SNR and CNR were found using ECG-gated ceMRA compared to standard ceMRA. CONCLUSION: The use of ECG gating in ceMRA results in artifact-free and sharper delineation of the structures of the heart and thoracic vessels.

[High-resolution T1-weighted MR-lymphography of inguinal lymph nodes after interstitial application of Gadomer-17 in animal experiments]. / Hochauflösende T1-gewichtete MR-Lymphographie inguinaler Lymphknoten nach interstitieller Applikation von Gadomer-17 im Tierexperiment.

PURPOSE: To evaluate the microstructural anatomy of inguinal lymph nodes in pigs after interstitial MR-lymphography with the dendritic contrast agent Gadomer-17. MATERIAL AND METHODS: High-resolution T1-weighted MR-lymphography was performed in inguinal lymph nodes of 10 domestic pigs (39 - 46 kg) after subcutaneous injection of 10 mumol/kg body weight Gadomer-17 in the hind legs of the animals. A 1.5T MR scanner and a ring-shaped surface coil were used. Two different high-resolution gradient-echo sequences with additionally reconstructed maximum-intensity projections were evaluated in a total of 20 lymph nodes. The high-resolution MR-findings were correlated with the histologic sections of the excised inguinal lymph nodes. RESULTS: Coronal T1-weighted 3D gradient-echo images (TR = 20 msec, TE = 6.1 - 8.3 msec, FA = 20 degrees ) with a slice thickness of 1 mm, a field-of-view of 120 mm and a matrix size of 256 x 256 (reconstructed to 1024 x 1024 voxels) yielding a reconstructed in-plane resolution of 117 x 117 microm (2) were best suited for the high-resolution MR lymphography of inguinal lymph nodes and enabled the differentiation of the hyperintense lymph node sinuses and hypointense lymphoid parenchyma of each lymph node (100 %). Even dilated lymphatic vessels evident in the histologic specimen were best demonstrated on the MIP images. CONCLUSION: High-resolution interstitial MR lymphography with Gadomer-17 allows the visualization of different tissue compartments of inguinal lymph nodes. This new technique is feasible on a routine 1.5T scanner and may offer potential for the detection of micrometastases in lymph nodes of cancer patients.

New optional IVC filter for percutaneous retrieval--in vitro evaluation of embolus capturing efficiency.

PURPOSE: In-vitro evaluation of a new caval filter (Cook Celect Filter) developed for delayed percutaneous retrieval in comparison to the Gunther Tulip filter. MATERIALS AND METHODS: The new Celect filter is constructed on the basis of the Tulip filter and consists of 4 primary anchoring legs and additional 8 thinner secondary wires to stabilize the filter and to guarantee adequate filtering efficiency. The filtering wires are of the same amount and equal distribution as the filtering wires of the Tulip filter. The secondary wires are arranged in such a way that percutaneous filter retrieval should be possible even if the wires are incorporated into the caval wall. In a flow model (tube size ø15-, ø22- and ø30 mm), the filter was exposed to single and multiple emboli (blood clots) of different sizes (3 x 5, 3 x 10, 5 x 10, 3 x 20, 5 x 20, 7 x 10, 7 x 20 to 10 x 24 mm) to analyse the embolus capturing efficiency under different conditions including eccentric and concentric, horizontal and vertical positions in comparison to the Tulip filter. All testing was carried out in SPSS analytic software; statistical significance was assumed for p-values < 0.05. RESULTS: The in-vitro embolus capturing efficiency of the Celect filter proved to be equivalent to the Tulip filter. In the single-embolus test, 91.6 % of the clots were captured by the Celect filter and 87.2 % by the Tulip filter (p = 0.042). Large clots ranging from 7 x 10 to 10 x 24 mm were captured in all cases, whereas the capture rates for the 3 x 5-mm and 3 x 10-mm clots were lower. The filters captured significantly more clots in the concentric than in the eccentric location. There was no significant difference between the overall capture rates of the two filters in the multi-clot test (72.2 % vs. 75.1 %), which showed deterioration of filter function during multiple clot exposure. With the 15-mm tube, the Celect filter had a significantly higher capture rate than the Tulip filter, whereas it was lower with the ø30-mm tube. There was no significant difference between the filters in a ø22-mm tube. The pressure gradient across the filters when exposed to blood clots ranged from 4.9 - 7.4 mm Hg for the Celect filter and 5.7 - 6.8 mm Hg for the Tulip filter in the single-embolus testing. There was no significant difference in the multi-clot tests. CONCLUSION: The new Celect filter showed similar in-vitro capture properties as the Gunther Tulip filter and deserves further in-vivo testing.

Evaluation of a Gadolinium-Based Nanoparticle (AGuIX) for Contrast-Enhanced MRI of the Liver in a Rat Model of Hepatic Colorectal Cancer Metastases at 9.4 Tesla.

PURPOSE: The aim of this study was to compare a Gd-based nanoparticle (AGuIX) with a standard extracellular Gd-based contrast agent (Gd-DOTA) for MRI at 9.4 T in rats with hepatic colorectal cancer metastases. MATERIALS AND METHODS: 12 rats with hepatic metastases were subjected to MRI using a 9.4 T animal scanner. T1w self-gated FLASH sequences (TR/TE = 45/2.5 ms, alpha = 45°, TA = 1: 23 min, FOV = 5.12 × 5.12 cm(2), matrix = 256 × 256) were acquired before and at 10 time points after contrast injection. Each animal received 0.1 mmol/kg BW Gd-DOTA i.v. 2 days later AGuIX was applied at 0.01 mmol/kg BW (representing equal Gd doses). The SNR of normal liver (SNRliver), hyper- and hypoenhancing parts of tumors (SNRtumor, hyperenh/SNRtumor, hypoenhanc), erector spinae muscle (SNRmuscle), CNR and lesion enhancement (LE) were calculated based on ROI measurements. RESULTS: Mean SNRliver (Gd-DOTA: 14.6 +/- 0.7; AGuIX: 28.2+/- 2.6, p < 0.001), SNRtumor, hyperenhanc (Gd-DOTA: 18.6 +/- 1.2; AGuIX: 29.6 +/- 2.8, p < 0.001), SNRtumor, hypoenhanc (Gd-DOTA: 12.0 +/- 0.7; AGuIX: 15.4 +/- 0.7, p < 0.001), SNRmuscle (Gd-DOTA: 12.3 +/- 0.3; AGuIX: 14.0 +/- 0.7, p < 0.001), mean CNR (Gd-DOTA: -2.5 +/- 0.2; AGuIX: -7.5 +/- 1.0, p < 0.001) and LE (Gd-DOTA: 3.8 +/- 0.7; AGuIX: 14.9 +/- 2.8, p = 0.001) were significantly higher using AGuIX. Regardless of the larger molecular size, AGuIX demonstrates an early peak enhancement followed by a continuous washout. CONCLUSION: AGuIX provides better enhancement at 9.4 T compared to Gd-DOTA for equal doses of applied Gd. This is based on the molecule structure and the subsequent increased interaction with protons leading to a higher relaxivity. AGuIX potentially ameliorates the conspicuity of focal liver lesions and may improve the sensitivity in diagnostic imaging of malignant hepatic tumors. KEY POINTS: AGuIX provides superior enhancement as compared to the extracellular compound Gd-DOTA at 9.4 T. AGuIX may improve the detection and diagnostic sensitivity of malignant focal liver lesions. The small size of AGuIX allows for fast renal clearance and prevents undesirable accumulation in the body.

Recurrent High-Flow Arterio-Venous Malformation of the Thyroid Gland.

BACKGROUND: Vascular malformations and hemangiomas of the thyroid gland are rare disorders. The first case of a patient with recurrent high-flow arterio-venous malformation of the right thyroid gland involving the right endolarynx is presented. PATIENT FINDINGS: In June 2013, a 42-year-old female patient presented to the surgical department with recurrent hoarseness and a soft, vibrating mass on the right side of her neck. In 1993, she underwent right subtotal hemithyroidectomy with embolization on the day before surgery for a high-flow arterio-venous malformation of the thyroid gland. Diagnostic work-up in 2013 demonstrated a complex recurrent high-flow arterio-venous malformation on the right side of her neck involving the endolarynx. Full function of the right vocal fold could not be ascertained. The lesion was embolized again and excised the following day. Intraoperative gross bleeding and scar tissue prevented visualization and monitoring of the recurrent laryngeal nerve. Gross bleeding was also noted on hemithyroidectomy after embolization in 1993. No therapy was needed for the endolaryngeal part of the lesion. Histology showed large arterio-venous malformations with thyroid tissue. She remains well without signs of recurrence 18 month later but with a definitive voice handicap. SUMMARY: This is the first report of a recurrent high-flow arterio-venous malformation originally developing from the right thyroid gland involving the right endolarynx. Counseling, diagnostic, and therapeutic work-up of the patient was possible only with an interdisciplinary team. The endolaryngeal part of the hemangioma dried out after embolization and completion hemithyroidectomy. Her hoarseness has greatly improved but a definitive voice handicap remains. CONCLUSION: High-flow arterio-venous malformations of the thyroid gland are a rare disease, and recurrent lesions have not been reported. Interdisciplinary management of these patients is mandatory due to the complex nature of the underlying pathology. Recurrence might develop after long free intervals.

Diagnosis of pulmonary arterial hypertension and pulmonary embolism with magnetic resonance angiography.

BACKGROUND: Pulmonary magnetic resonance angiography (PMRA) has been proven to be accurate for the diagnosis of suspected acute or chronic pulmonary embolism (PE). Only limited data exist on the reliability of PMRA for the diagnosis of acute and chronic pulmonary artery hypertension (PAH). The aim of this study was to determine the accuracy of PMRA in the differentiation between patients suffering from PAH of varying etiologies. METHODS: Fifty patients (21 women; mean [+/- SD] age, 52 +/- 16 years) were examined with gadolinium-enhanced PMRA for the evaluation of pulmonary artery (PA) disease. The diagnosis of PAH (ie, systolic PA pressure of > 35 mm Hg) was determined by Doppler echocardiography. The criteria for the diagnosis of chronic PAH by PMRA were dilated central PAs (diameter > 28 mm) and abnormal proximal-to-distal tapering of the PAs. The diagnostic criterion for acute and chronic PE was the presence of an intravascular filling defect. RESULTS: Chronic PAH was present in 18 patients, which was correctly identified by PMRA in 16 patients (sensitivity, 89%). All patients without PAH had normal findings on PMRA (specificity, 100%). Only 1 of 18 patients with normal findings on PMRA showed moderate chronic PAH (negative predictive value, 94%). PAH due to acute/subacute pulmonary thromboembolism (15 patients) was identified in all patients (sensitivity, 100%). Acute PAH was differentiated from chronic PAH in all cases by the detection of intravascular filling defects and the lack of abnormal proximal-to-distal tapering of PAs. CONCLUSIONS: PMRA is a promising noninvasive imaging modality for the identification of patients with acute or chronic PAH. This technique should be considered a sensitive and highly specific screening tool for suspected chronic PAH.

Contrast-enhanced magnetic resonance urography. First experimental results with a polymeric gadolinium bloodpool agent.

RATIONALE AND OBJECTIVES: The authors investigated the feasibility of contrast-enhanced excretory magnetic resonance urography to visualize the nonobstructed urinary tract with a macromolecular gadolinium-based bloodpool agent. METHODS: Excretory magnetic resonance imaging was performed in seven pigs using a T1-weighted three dimensional fast-field-echo sequence before and up to 120 minutes after administration of a gadolinium bloodpool prototype agent. RESULTS: During the first 15 minutes after injection, the urographic effect was predominantly poor. Visualization of the entire urinary tract was excellent in four pigs and incomplete but satisfactory in three 105 minutes after injection. Furosemide application was tested in one case, which improved image quality effectively. Corresponding to the physiological excretion rate, signal measurements in the renal parenchyma revealed a gradual decrease of the initially distinct contrast enhancement. CONCLUSIONS: T1-weighted contrast-enhanced magnetic resonance urography using a polymeric gadolinium bloodpool allows detailed visualization of the normal urinary tract, while information about the excretory function is obtained simultaneously. However, application of a diuretic seems to be essential to prevent lengthy examination duration.

Interventional magnetic resonance. Initial clinical experience with a 1.5-tesla magnetic resonance system combined with c-arm fluoroscopy.

RATIONALE AND OBJECTIVES: The authors evaluate the feasibility of performing magnetic resonance (MR) procedures on a 1.5-tesla (T) system combined with conventional c-arm fluoroscopy. METHODS: A 1.5-T MR imaging system was combined with a conventional c-arm fluoroscopy unit in one room. The two systems were connected via a floating table top. Twenty-six interventional procedures (biopsies, MR-portography, percutaneous alcohol injection, laser ablation, fluid aspiration, and breast marking) were performed in 22 patients under MR, fluoroscopic control, or both. For MR guidance, fast gradient echo sequences were used, initiated from a panel at the front of the magnet. Images were displayed on an liquid crystal display screen positioned on the magnet. RESULTS: All MR-guided procedures were performed successfully without complications. The addition of c-arm fluoroscopy was useful for bone interventions and MR-portography. All diagnostic biopsies yielded sufficient amounts of tissue for histologic diagnosis. In breast lesions, the target identified on dynamic MR imaging was marked correctly in each case. In interstitial laser thermotherapy the laser effect could be visualized, and in percutaneous ethanol injection the distribution of the alcohol could be seen. Both imaging systems worked without image distortions and high-quality MR images were obtained. CONCLUSIONS: The combination of a 1.5-T MR imager with a c-arm fluoroscopy system seems to be a promising technical solution for performing interventional MR procedures.