Effects of state-wide implementation of the Los Angeles Motor Scale for triage of stroke patients in clinical practice.

BACKGROUND: The prehospital identification of stroke patients with large-vessel occlusion (LVO), that should be immediately transported to a thrombectomy capable centre is an unsolved problem. Our aim was to determine whether implementation of a state-wide standard operating procedure (SOP) using the Los Angeles Motor Scale (LAMS) is feasible and enables correct triage of stroke patients to hospitals offering (comprehensive stroke centres, CSCs) or not offering (primary stroke centres, PSCs) thrombectomy. METHODS: Prospective study involving all patients with suspected acute stroke treated in a 4-month period in a state-wide network of all stroke-treating hospitals (eight PSCs and two CSCs). Primary endpoint was accuracy of the triage SOP in correctly transferring patients to CSCs or PSCs. Additional endpoints included the number of secondary transfers, the accuracy of the LAMS for detection of LVO, apart from stroke management metrics. RESULTS: In 1123 patients, use of a triage SOP based on the LAMS allowed triage decisions according to LVO status with a sensitivity of 69.2% (95% confidence interval (95%-CI): 59.0-79.5%) and a specificity of 84.9% (95%-CI: 82.6-87.3%). This was more favourable than the conventional approach of transferring every patient to the nearest stroke-treating hospital, as determined by geocoding for each patient (sensitivity, 17.9% (95%-CI: 9.4-26.5%); specificity, 100% (95%-CI: 100-100%)). Secondary transfers were required for 14 of the 78 (17.9%) LVO patients. Regarding the score itself, LAMS detected LVO with a sensitivity of 67.5% (95%-CI: 57.1-78.0%) and a specificity of 83.5% (95%-CI: 81.0-86.0%). CONCLUSIONS: State-wide implementation of a triage SOP requesting use of the LAMS tool is feasible and improves triage decision-making in acute stroke regarding the most appropriate target hospital.

Significant improvement of laparoscopic knotting time in medical students through manual training with potential cost savings in laparoscopy - an observational study

Objective: Laparoscopy is a standard procedure in operative gynaecology, but laparoscopic simulator training for novices/junior surgeons is not currently well-established. The aims of this study were to demonstrate that a laparoscopic knot course for trainees can significantly shorten the knotting time and to perform a counter-value calculation for the clinic's costs. Material and Methods: An observational study was performed with exercises on a laparoscopic box trainer as part of the practical clerkship in gynaecology and obstetrics between 07.10.2019-31.01.2020. At the beginning and at the end of the exercises, the participants made a laparoscopic knot and the difference in knotting time, Δt in seconds (s) was measured. Results: Eighty-eight medical students needed an average of 247.1 s for the first laparoscopic knot at the beginning of the course and an average of 45.43 s for the second at the end of the course. Mean shortening of the knotting time was 201.67 s or 81.6% (p=0.02). Calculating costs of an average of €40-50 for an operation minute would mean a cost saving of at least €120-150 for a partial node. Conclusion: Trainees can significantly improve their operative skills in a short time with the aid of surgical simulation training. Such training can be beneficial for clinics by reducing the operating time if the basics, such as sewing and instrument guidance, are learned on a simulator. We therefore suggest that operative simulation training should be mandatory in medical education.

Prehospital Stroke Management Optimized by Use of Clinical Scoring vs Mobile Stroke Unit for Triage of Patients With Stroke: A Randomized Clinical Trial.

Importance: Transferring patients with large-vessel occlusion (LVO) or intracranial hemorrhage (ICH) to hospitals not providing interventional treatment options is an unresolved medical problem. Objective: To determine how optimized prehospital management (OPM) based on use of the Los Angeles Motor Scale (LAMS) compares with management in a Mobile Stroke Unit (MSU) in accurately triaging patients to the appropriate hospital with (comprehensive stroke center [CSC]) or without (primary stroke center [PSC]) interventional treatment. Design, Setting, and Participants: In this randomized multicenter trial with 3-month follow-up, patients were assigned week-wise to one of the pathways between June 15, 2015, and November 15, 2017, in 2 regions of Saarland, Germany; 708 of 824 suspected stroke patients did not meet inclusion criteria, resulting in a study population of 116 adult patients. Interventions: Patients received either OPM based on a standard operating procedure that included the use of the LAMS (cut point ≥4) or management in an MSU (an ambulance with vascular imaging, point-of-care laboratory, and telecommunication capabilities). Main Outcomes and Measures: The primary end point was the proportion of patients accurately triaged to either CSCs (LVO, ICH) or PSCs (others). Results: A predefined interim analysis was performed after 116 patients of the planned 232 patients had been enrolled. Of these, 53 were included in the OPM group (67.9% women; mean [SD] age, 74 [11] years) and 63 in the MSU group (57.1% women; mean [SD] age, 75 [11] years). The primary end point, an accurate triage decision, was reached for 37 of 53 patients (69.8%) in the OPM group and for 63 of 63 patients (100%) in the MSU group (difference, 30.2%; 95% CI, 17.8%-42.5%; P < .001). Whereas 7 of 17 OPM patients (41.2%) with LVO or ICH required secondary transfers from a PSC to a CSC, none of the 11 MSU patients (0%) required such transfers (difference, 41.2%; 95% CI, 17.8%-64.6%; P = .02). The LAMS at a cut point of 4 or higher led to an accurate diagnosis of LVO or ICH for 13 of 17 patients (76.5%; 6 triaged to a CSC) and of LVO selectively for 7 of 9 patients (77.8%; 2 triaged to a CSC). Stroke management metrics were better in the MSU group, although patient outcomes were not significantly different. Conclusions and Relevance: Whereas prehospital management optimized by LAMS allows accurate triage decisions for approximately 70% of patients, MSU-based management enables accurate triage decisions for 100%. Depending on the specific health care environment considered, both approaches are potentially valuable in triaging stroke patients. Trial Registration: ClinicalTrials.gov identifier: NCT02465346.

Stroke in an adult with HIV infection due to carotid artery stenosis successfully treated with steroids: HIV-associated arteritis?

A 33-year-old Caucasian man with a 17-year history of HIV infection developed sudden right-sided hemiplegia, with the arm more affected than the leg, and aphasia. Magnetic resonance imaging of the brain showed hemodynamic watershed stroke between the anterior and middle cerebral artery territories and an ischemic stroke within the left posterior middle cerebral artery territory. Color-coded Duplex sonography and Doppler sonography revealed hypoechogenic stenosis of the left common carotid artery, the left internal carotid artery, left external carotid artery and right internal carotid artery. An extensive diagnostic workup led us to hypothesize that HIV-associated arteritis was the cause of the stroke, and following intravenous steroid therapy, the carotid artery stenoses vanished.

Preclinical evaluation of a novel fiber compound MR guidewire in vivo.

PURPOSE: Interventional magnetic resonance imaging requires dedicated and MR-compatible devices. The guidewire is a key item for intravascular interventions. Mechanical stability, good visibility during real-time imaging, and RF safety are essential. A novel fiber-compound MR guidewire (GW) was evaluated in different MR-guided interventional scenarios. MATERIALS AND METHODS: The GW (diameter 0.032") consists of a fiber-compound produced using a micropultrusion technique doped with iron particles and a 10-cm Nitinol tip. Several iron splints are additionally attached at regular distances to visualize GW-movement. A protective polymer jacket with hydrophilic coating covers the core material. As approved by the government committee on animal investigations, the GW was evaluated in 5 pigs. Under complete MR-guidance, catheterization of the carotid and renal arteries, segmental arteries of the kidneys, the contralateral inguinal artery, and the left ventricle was performed using real-time gradient echo sequences in a 1.5 Tesla scanner. Different interventional applications including balloon dilatation, stent deployment, and embolization of small vessels were investigated. The time to probe the vessels under magnetic resonance imaging guidance and visibility of the GW are assessed. Handling and visibility under fluoroscopy were compared with a standard Nitinol guidewire as a benchmark. RESULTS: On real-time magnetic resonance imaging, the iron-induced artifacts enabled a distinct visualization of the GW shaft and of its markings with a mean size of 2.6 mm and 5.4 mm, respectively. This facilitated fast navigation to the target vessels (averages: renal arteries 16 seconds, carotid artery 5 seconds, and contralateral inguinal artery 42 seconds.) with an exact depiction of the respective vessel. All interventional procedures were performed successfully. No GW-related side effects as kinking or breakage of the wire or GW induced blood-clotting were observed. All interventionalists assessed handling of the GW to be nearly equal in terms of stiffness, flexibility, and guidance compared with a standard Nitinol guidewire. X-ray visibility was less distinct but still diagnostically good. CONCLUSION: With the aid of the GW, different fully real-time MR-guided endovascular interventions become feasible.

Unmasking pedal arteries in patients with critical ischemia using time-resolved contrast-enhanced 3D MRA.

OBJECTIVE: To test the diagnostic relevance of fast Gadobenate dimeglumine (Gd-BOPTA) enhanced, time-resolved, three-dimensional magnetic resonance angiography (t3D MRA) of distal calf and pedal vasculature in critical limb ischemia in a prospective comparison with conventional selective digital subtraction angiography (DSA) and high-resolution duplex ultrasound (US) scan. METHODS: From April 2007 to June 2008, 34 feet of 29 consecutive patients suffering from limb-threatening ischemia underwent diagnostic US scan, DSA, and t3D MRA before treatment. The investigations took place within 3 days. A t3D MRA was performed using a 3 Tesla whole-body magnetic resonance (MR) system with an eight-element phased-array coil. Image quality and diagnostic findings were subjectively analyzed by two radiologists and one vascular surgeon. Each distal calf and foot was divided into six arterial segments for DSA and t3D MRA, and four segments were investigated by US scan. Patency or occlusion was studied with all the techniques, whereby DSA and t3D MRA were additionally evaluated in patients having greater or less than 50% stenosis. Finally, images were visually assessed by the three observers by applying a six-point grading scale. The acquired data was statistically analyzed using McNemar's test and Wilcoxon's matched-pairs signed-rank sum test. The P values of less than an alpha level of .05 were considered to be statistically significant. RESULTS: We achieved MRA images of diagnostic quality in all patients. Significantly more patent pedal arteries were identified by applying t3D MRA than DSA (P < .001) and US scan (P < .02). For estimating the degree of stenosis, no technique proved to be superior (P > .28). Overall image quality was rated best for t3D MRA. Additionally, potential bypass target vessels could be clearly discriminated from pedal veins due to the temporal resolution. CONCLUSION: In our prospective study, t3D MRA has been proven to be superior to DSA and US scan in pedal vasculature imaging in critical limb ischemia. This is a valuable, noninvasive method for detecting potential pedal bypass target arteries.

Imaging of the coronary venous system in patients with congestive heart failure: comparison of 16 slice MSCT and retrograde coronary sinus venography: comparative imaging of coronary venous system.

BACKGROUND: Knowledge of the anatomy of the coronary venous system (CVS) is important for planning of cardiac interventions like cardiac resynchronization therapy or percutaneus mitral annuloplasty. Different methods have been used for preprocedural visualization of the CVS. However, limited data is available comparing invasive retrograde coronary sinus angiography (CSA) and non-invasive multi slice computed tomography (MSCT). Thus, a comparison of retrograde CSA and ECG-gated MSCT for the visualization of the CVS in patients with congestive heart failure (CHF) was performed. METHODS: 20 patients (male: 11) with CHF underwent CSA and MSCT (16 x 0.75 mm collimation, tube voltage: 120 kV, tube current: 550 mAs(eff)). Both methods were compared with respect to vessel diameter and visibility. RESULTS: Vessel visualization was better using retrograde CSA except for middle cardiac vein and small veins which were better seen with MSCT. Overall, there was a trend that MSCT detected more vessels. Vessel diameters were larger measured using retrograde CSA, but only statistically significant for the coronary sinus and middle cardiac vein. CONCLUSION: Whereas MSCT is more suitable for an overview, retrograde CSA offers a more detailed visualization of the CVS including marginal and posterior veins than MSCT. Thus, retrograde CSA allows a better display of target vessels commonly used for cardiac interventions. Overall, these two imaging techniques offer complementary information.

Evaluation of the accuracy of three different computer-aided surgery systems in dental implantology: optical tracking vs. stereolithographic splint systems.

OBJECTIVES: In dental implant surgery, computer-aided surgery (CAS) techniques can provide a high medical benefit. Two different techniques are established for transferring a CAS treatment planning to the patient: the use of surgical templates (splints) or intraoperative navigation using optical tracking. The aim of this study was to evaluate the total application accuracy of three different CAS systems (Artma virtual patient, RoboDent LapAccedo, Materialise SurgiGuide): two featuring optical tracking, one featuring stereolithographically manufactured splints. MATERIALS AND METHODS: A total of 120 implants were placed into 20 human cadaver mandibles. Preoperative computed tomography (CT) scans imported to the corresponding software were used to plan the implant positions on the computer. Implant placement was performed using either optical tracking or stereolithographic splints. Postoperative CT scans were used to obtain the achieved implant positions. A semi-automatic approach was developed to compare planned and achieved implant positions. Deviations between planned and achieved positions were measured for each implant in position (Delta xy), depth (Delta z) and axis (Delta phi). CONCLUSION: Despite the different techniques of transfer, no statistically significant differences were found between all groups. The accuracy achieved corresponded well with the spatial resolution of the CT Scans used.

Assessment of global left and right ventricular function using dual-source computed tomography (DSCT) in comparison to MRI: an experimental study in a porcine model.

OBJECTIVE: We sought to evaluate the ability of retrospectively ECG-gated dual-source computed tomography (DSCT) to assess left (LV) and right ventricular (RV) functional parameters in comparison to 1.5 T magnetic resonance imaging (MRI). MATERIALS AND METHODS: Ten domestic pigs (60 kg) underwent both contrast-enhanced cardiac DSCT and cardiac MRI using standardized examination protocols under general anesthesia. From manually drawn endocardial and epicardial contours, LV and RV end-systolic (ESV) and end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF), myocardial mass (MM), peak filling rate (PFR), peak ejection rate (PER), time to peak ejection (TPE), and time to peak filling (TPF) were calculated by means of dedicated analysis software. LV and RV functional parameters were analyzed using Bland-Altman plots, Student t test, and Pearson's correlation coefficient. RESULTS: Both left and right ESV and EDV, SV and EF determined with DSCT correlated well with MR imaging results (left, r = 0.98/0.92/0.82/0.98; right, r = 0.90/0.94/0.96/0.94). PER, PFR, TPE, TPF, and MM showed only a moderate to low correlation (left, r = 0.67/0.37/0.23/0.35/0.57; right, r = 0.78/0.69/0.12/0.11/0.44). PER and PFR were significantly underestimated by DSCT when compared with MRI. CONCLUSIONS: Retrospectively ECG-gated DSCT correctly depicts end-systole and can accurately determine LV and RV volumes, SV, and EF in comparison to MRI. DSCT showed a significant underestimation of PER and PFR in comparison to MRI.

Molecular MRI of cerebral venous sinus thrombosis using a new fibrin-specific MR contrast agent.

BACKGROUND AND PURPOSE: Imaging of cerebral vein thrombosis is still challenging. Currently, diagnosis is based on CT venography and MRI including MRA and conventional digital subtraction angiography. However, especially in chronic cases, each method has shown its limitations. Newer strategies for MRI are found on molecular imaging using targeted contrast agents. The aim of this study was to prove the feasibility of a novel fibrin-targeted MR contrast agent (EP-2104R; EPIX Pharmaceuticals) for selective imaging of sinus venous thrombosis in an animal model. METHODS: Thrombosis of the superior sagittal sinus with human blood was induced in 6 pigs using a combined microsurgical and interventional approach. MRI was then performed before and up to 120 minutes after injection of 4 micromol/kg body weight EP-2104R. Molecular imaging was performed with a 3-dimensional high-resolution T1-weighted gradient echo sequence. Time courses of signal-to-noise ratio and contrast-to-noise ratio were analyzed. Thrombi were then surgically removed and the Gadolinium concentration was assessed. RESULTS: In all cases the thrombosis could be successfully induced; the complete MR protocol could be performed in 5 animals. In these cases the thrombi showed selective enhancement after injection of the molecular contrast agent. However, a continuous contrast-to-noise ratio increase was seen up to 120 minutes after contrast administration, achieving a contrast-to-noise ratio of 14.2+/-0.7 between clot and the blood pool. CONCLUSIONS: The novel fibrin-targeted molecular MR contrast EP-2104R allows selective and high-contrast imaging of cerebral sinus vein thrombosis in an animal model.

Imaging of the coronary venous system: retrograde coronary sinus angiography versus venous phase coronary angiograms.

BACKGROUND: Left ventricular lead implantation for cardiac resynchronization therapy (CRT) usually requires a pre- or intraprocedural occlusion contrast venography of the coronary sinus (CS) in order to identify tributaries to the lateral wall. As many patients undergo a preprocedural coronary angiogram, we investigated the diagnostic accuracy of venous phase imaging of the CS in patients prior to CRT implantation. The aim of this study was to assess the quality of venous phase coronary sinus angiography. METHODS: In 24 CRT patients retrograde occlusion venography and venous phase coronary sinus angiography obtained during coronary angiography were compared with respect to image quality, vessel diameters and the ability to identify a coronary sinus side branch suitable for left ventricular lead placement. RESULTS: Suitable target vessels for left ventricular lead implantation were identified in all patients irrespective of the method (retrograde occlusion venography or venous phase coronary sinus angiography). There was a high concordance in vessel diameters between venous phase and retrograde angiography. Visibility was superior in retrograde venography. CONCLUSIONS: In heart failure patients who are scheduled for coronary angiograms venous phase coronary sinus angiography is a time-saving and easy to perform alternative imaging modality. Radiation exposure and the amount of contrast medium needed is reduced as compared to coronary sinus occlusion angiography. The information obtained thereby may be used to plan subsequent CRT implantation without the need for retrograde coronary sinus angiography.

Multislice computed tomography perfusion imaging for visualization of acute pulmonary embolism: animal experience.

The purpose of our animal study was to evaluate a new computed tomography (CT) subtraction technique for visualization of perfusion defects within the lung parenchyma in subsegmental pulmonary embolism (PE). Seven healthy pigs were entered into a prospective trial. Acute PE was artificially induced by fresh clot material prior to the CT scans. Within a single breath-hold, whole thorax CT scans were performed with a 16-slice multidetector-row CT scanner (SOMATOM Sensation 16; Siemens, Forchheim, Germany) before and after intravenous application of 80 ml of contrast medium with a flow rate of 4 ml/s, followed by a saline chaser. The scan parameters were 120 kV and 100 mAs(eff), using a thin collimation of 16x0.75 mm and a table speed/rotation of 15-18 mm (pitch, 1.25-1.5; rotation time, 0.5 s). Axial source images were reconstructed with an effective slice thickness of 1 mm (overlap, 30%). A new automatic subtraction technique was used. After 3D segmentation of the lungs in the plain and contrast-enhanced series, threshold-based extraction of major airways and vascular structures in the contrast images was performed. This segmentation was repeated in the plain CT images segmenting the same number of vessels and airways as in the contrast images. Both scans were registered onto each other using nonrigid registration. After registration both image sets were filtered in a nonlinear fashion excluding segmented airways and vessels. After subtracting the plain CT data from the contrast data the resulting enhancement images were color-encoded and overlaid onto the contrast-enhanced CT angiography (CTA) images. This color-encoded combined display of parenchymal enhancement of the lungs was evaluated interactively on a workstation (Leonardo, Siemens) in axial, coronal and sagittal plane orientations. Axial contrast-enhanced CTA images were rated first, followed by an analysis of the combination images. Finally, CTA images were reread focusing on areas with perfusion deficits indicating PE on the color-coded enhancement display. Subtraction was feasible for all seven studies. In one animal, opacification of the pulmonary arteries was suboptimal owing to heart insufficiency. In the remaining six pigs, a total of 37 perfusion defects were clearly assessable downstream of occluded subsegmental arteries, showing lower or missing enhancement compared with normally perfused lung parenchyma. Indeterminate findings from CTA showed typical PE perfusion defects in four out of six cases on CT subtraction. Additionally, 22 peripheral triangular-shaped enhancement defects were delineated. Nine of these findings were reclassified as definitely being caused by PE on second reading of the CTA data sets. Our initial results have shown that this new subtraction technique for perfusion imaging of PE is feasible, using routine contrast delivery. Dedicated examination protocols are mandatory for adequate opacification of the pulmonary arteries and for optimization of data sets for subsequent subtraction. Perfusion imaging allows a comprehensive assessment of morphology and function, providing more accurate information on acute PE.

Feasibility of pulmonary ventilation visualization with aerosolized magnetic resonance contrast media.

OBJECTIVE: The objective of this study was to evaluate a new approach to noninvasive magnetic resonance assessment of human pulmonary ventilation with aerosolized Gd-DTPA. MATERIALS AND METHODS: Fifteen experimental procedures were carried out in 15 healthy volunteers on a 1.5-T imager. For a timespan of 10 minutes, the subjects spontaneously inhaled a commercially available Gd-DTPA magnetic resonance contrast agent in aerosolized form through an inflatable facemask. Gd-DTPA was aerosolized by means of a small-particle generator with integrated heater to increase aerosol production. Respiratory gated dynamic T1-weighted turbo spin echo images were obtained before and after contrast agent aerosol administration. After nebulization, homogeneity of aerosol distribution was graded by 2 experienced readers and pulmonary signal intensity (SI) changes were measured in corresponding regions of both lungs. RESULTS: Pulmonary ventilation visualization, and hence contrast agent delivery, was rated homogeneously distributed by both readers in 14 of 15 cases (93.3%) and slightly inhomogeneous in 1 case (6.7%). Pulmonary SI increased by an average of +37% +/- 8.5 (range, 10-48%). Allergic responses were not noted. CONCLUSIONS: Human ventilation imaging with aerosolized gadolinium-chelates is viable. The presented modality might evolve as an alternative to current nuclear medicine and magnetic resonance image ventilation imaging procedures, avoiding radiation exposure while offering functional ventilation assessment with an acceptable temporal and spatial resolution. Nevertheless, further evaluation is required to define the potential of gadolinium-based ventilation magnetic resonance imaging in illustrating lung disease.

Cine MR imaging of heart valve dysfunction with segmented true fast imaging with steady state free precession.

PURPOSE: To evaluate the value of cine true fast imaging with steady-state free precession (SSFP) for semiquantitative assessment of valvular dysfunction in the heart and to compare the results to that obtained with a standard breath-hold segmented gradient-recalled echo-planar imaging sequence (GE-EPI). MATERIALS AND METHODS: Twenty-three patients with known valvular dysfunction (main component: 16 with aortic valve stenosis, nine with aortic valve insufficiency, three with mitral stenosis, two with mitral regurgitation, two with tricuspidal regurgitation, and one with pulmonary stenosis) and 23 control subjects with normal valvular function underwent MR imaging on a 1.5-T system (ACS-NT, Philips, Best, The Netherlands). Cine SSFP and GE-EPI images were acquired in identical long-axis views. Images were evaluated for the presence and extent of the signal void arising from the valves and for image quality consensus by two experienced radiologists. Results were compared to those obtained by cardiac catheterization (in 16 patients) or color Doppler (in the remaining seven patients). RESULTS: On SSPF images, the complex flow pattern in valvular regurgitant or stenotic lesions caused signal void within the bright blood pool of the atria or ventricles, similar to GE-EPI, in all patients. Valvular dysfunction was delineated using SSFP with the same high sensitivity (100%) as using the GE-EPI sequence. Results correlated to those obtained by cardiac catheterization or color Doppler ultrasonography (P < 0.001, r = 0.97). However, the jet phenomenon was slightly more pronounced in five patients on GE-EPI. There was no significant signal void in the 23 control subjects with both sequences. In all 46 subjects, the image quality of SSFP images was rated higher (P < 0.05; 2.6 +/- 0.1; using a scale ranging from 0-3) compared to GE-EPI (1.7 +/- 0.1). CONCLUSION: The results of this study suggest that valvular dysfunction can be semiquantitatively assessed using SSFP cine MR imaging.

Gadolinium containing contrast agents for pulmonary ventilation magnetic resonance imaging: preliminary results.

RATIONALE AND OBJECTIVES: Five gadolinium containing contrast media (gadopentetate dimeglumine [Magnevist; Berlex Imaging, Montville, NJ, USA], gadobutrol [Gadovist; Schering, Järfälla, Sweden], gadoteridol [ProHance; Bracco-Byk Gulden, Konstanz, Germany], gadobenate dimeglumine [MultiHance; Bracco-Byk Gulden, Konstanz, Germany], and gadopentetate dimeglumine added with mannitol and a surface active detergent) were evaluated for their efficacy in magnetic resonance depiction of lung ventilation. METHODS: All contrast agent aerosols were generated by a jet nebulizer. Twelve intubated domestic pigs were mechanically ventilated with the respective aerosolized contrast agent and studied on a 1.5 T MR imager. T1-weighted TSE images using respiratory gating were obtained before and after a 10-minute ventilation period. Pulmonary signal intensity (SI) and signal-to-noise (SNR) changes were measured for both lungs. RESULTS: Mean SI increases ranged between 13.5% and 45.8% (right lung) and 14% and 39.8% (left lung). SNR changes ranged from +14.7% to +46.8% and from +13.1% to +40.5% for the right and left lung, respectively. The highest SI and SNR increases were observed in the gadoteridol group. CONCLUSIONS: The use of gadolinium for MR ventilation imaging is primarily hindered by its viscosity properties and thus, its capability of aerosolization. Of the five agents tested, the medium with the lowest viscosity at room temperature (gadoteridol) showed the most promising enhancement results. The results reaffirm the potential of gadolinium-based contrast agents as a pulmonary imaging alternative. With a reduction of ventilation duration down to ten minutes, the method appears tolerable in a clinical setting.