Radiation dose optimization for CT-guided interventional procedures in the abdomen and pelvis

Radiation dose to patients can be high for some CT-guided interventional procedures in the abdomen and pelvis, especially tumor ablations. Strategies for radiation dose reduction include choosing an alternative guidance modality that does not use radiation whenever feasible, restricting the cranio-caudal length of interventional scans to the interventional target, and refinement of technical skills in order to minimize the number of scans acquired for interventional guidance. Dose optimization for these procedures is best achieved by lowering the tube current relative to the prior diagnostic scan, choosing dose efficient scanning modes, and using intermittent-mode, narrowly collimated CT fluoroscopy for interventional guidance.

Musculoskeletal aspiration procedures

With advances in imaging technology, there has been a significant increase in the number and range of interventional musculoskeletal image-guided procedures. One of the most commonly performed image-guided musculoskeletal interventions is the diagnostic and therapeutic percutaneous aspiration and drainage of multiple types of intra-articular, juxta-articular, and intramuscular pathologic fluid collections. These procedures may be performed under fluoroscopic, ultrasound, computed tomography, or even magnetic resonance guidance depending on the location to be accessed, type of pathology, patient characteristics, and operator preference. Musculoskeletal image-guided aspiration and drainage procedures are minimally invasive and generally very safe while offering valuable diagnostic information as well as therapeutic benefit. This article focuses on the appropriate indications, contraindications, and general technique for accessing the major joints via imaging guidance. For each joint, we discuss pertinent anatomy, appropriate imaging modalities, and preferred approaches to gaining intra-articular access. Additionally, the article discusses some of the more frequently encountered juxta-articular and intramuscular fluid collections that can be accessed and aspirated via percutaneous intervention, with mention of the importance of recognizing extremity sarcomas that can mimic these benign collections.

Transcatheter arterial embolization of anomalous systemic arterial supply to the basal segment of the lung

We describe the case of a 67-year-old woman with an anomalous systemic arterial supply to the basal segment of the lung, which was managed successfully by transcatheter arterial embolization (TAE) with microcoils. Her chest computed tomography (CT) scan showed diffuse ground-glass opacity in the left lower lobe, no bronchial abnormalities, and blood supply from an anomalous artery originating from the descending thoracic aorta, with drainage to the normal pulmonary vein. We successfully performed TAE under balloon occlusion of the anomalous artery, without complications. TAE is a minimally invasive, safe, and valuable method, and could be used as first-line treatment in such cases.

Evaluation of ultrasound-guided vascular access in dogs

OBJECTIVE

To describe the technique and determine the feasibility, success rate, perceived difficulty, and time to vascular access using ultrasound guidance for jugular vein catheterization in a cardiac arrest dog model.

DESIGN

Prospective descriptive study.

SETTING

University teaching hospital.

ANIMALS

Nine Walker hounds.

MEASUREMENTS AND MAIN RESULTS

A total of 27 jugular catheterizations were performed postcardiac arrest using ultrasound guidance. Catheterizations were recorded based on the order in which they were performed and presence/absence of a hematoma around the vein. Time (minutes) until successful vascular access and perceived difficulty in achieving vascular access (scale of 1 = easy to 10 = difficult) were recorded for each catheterization. Mean time to vascular access was 1.9 minutes (95% confidence interval, 1.1-3.4 min) for catheterizations without hematoma, versus 4.3 minutes (1.8-10.1 min) for catheterizations with hematoma (P = 0.1). Median perceived difficulty was 2 of 10 (range 1-7) for catheterizations without hematoma, versus 2 of 10 (range 1-8) for catheterizations with hematoma (P = 0.3). A learning curve was evaluated by comparing mean time to vascular access and perceived difficulty in initial versus subsequent catheterizations. Mean time to vascular access was 2.5 minutes (1.0-6.4 min) in the initial 13 catheterizations versus 3.3 minutes (1.5-7.5 min) in the subsequent 14 catheterizations (P = 0.6). Median perceived difficulty in the first 13 catheterizations (3, range 1-8) was significantly greater (P = 0.049) than median perceived difficulty in the subsequent 14 catheterizations (2, range 1-6).

CONCLUSIONS

Ultrasound-guided jugular catheterization is associated with a learning curve but is successful in obtaining rapid vascular access in dogs. Further prospective studies are warranted to confirm the utility of this technique in a clinical setting.

Gastroduodenal artery recanalization after transcatheter fibered coil embolization for prevention of hepaticoenteric flow: incidence and predisposing technical factors in 142 patients

BACKGROUND

Prophylactic occlusion of extrahepatic vessels prior to radioembolization or chemotherapy infusion is an effective method to prevent gastrointestinal complications. Unfortunately, vascular recanalization can occur.

PURPOSE

To retrospectively determine the rate and technical factors associated with gastroduodenal artery (GDA) recanalization after transcatheter occlusion with fibered coils.

MATERIAL AND METHODS

Patients with hepatic malignancy who underwent fibered coil occlusion of the GDA origin for radioembolization or hepatic arterial chemotherapy infusion with at least one subsequent hepatic angiogram between March 2006 and January 2011 were included. One hundred and forty-two patients (men, 71; women, 71) met study criteria. Hepatic arteriograms were reviewed to determine the frequency of arterial recanalization. Additional parameters included: patients' demographics, GDA diameter, length of coil pack, distance between GDA origin and most cephalad coil, persistent flow at the conclusion of the initial GDA occlusion procedure, platelet count, and international normalized ratio (INR). Chi-square test and pooled t-test were used to compare the two groups. Prospective multivariate analysis was performed with a logistic regression model.

RESULTS

Twenty-nine of 142 patients (20.4%) experienced GDA recanalization. The distance between the GDA origin and most cephalad coil was significantly greater in the recanalization group than in the non-recanalization group (9.6 mm vs. 12.6 mm, P = 0.01). A prospective multivariate analysis established that the further the coil was from the origin the more likely the GDA was to recanalize. The two groups did not differ on the basis of any other factors examined.

CONCLUSION

GDA origin recanalization after fibered coil occlusion is common. The distance between the GDA origin and most cephalad coil appears to be a predisposing factor for recanalization. Familiarity with this phenomenon is beneficial to reduce the likelihood of gastrointestinal tract complications during hepatic locoregional therapy.

A fatal complication of ultrasound-guided abdominal paracentesis

Ultrasound-guided abdominal paracentesis is a procedure that is frequently performed by radiologists for both diagnostic and therapeutic purposes. This procedure has been shown to be safe with few complications. We report the case of a patient who underwent an ultrasound-guided therapeutic abdominal paracentesis for refractory ascites complicated by intraperitoneal hemorrhage leading to death. This case suggests that ultrasound-guided paracentesis may need to become a more standardized procedure and that in the event of hemorrhage, alternative treatment options such as embolization or surgical intervention should be utilized when manual compression fails.

Comparison of ultrasound guidance with the traditional palpation and fluoroscopy method for the common femoral artery puncture

OBJECTIVES

To compare the success and complication rates of ultrasound-guided or palpation-guided punctures of the common femoral artery in a prospective randomized study.

BACKGROUND

Percutaneous femoral arterial access is sometimes difficult to perform and is the source of complications. It has not been established whether ultrasound-guided puncture of the common femoral artery is the standard practice for angiography.

MATERIALS AND METHODS

Two hundred and eight patients were randomized into two groups. One had ultrasound-guided puncture and the other had palpation-guided puncture of the common femoral artery. The technical success, first pass success rate, total number of attempts required for access, time to sheath insertion, pain during puncture, and access-related complication were compared.

RESULTS

Technical success tended to be higher and the complication rates tended to be lower in the ultrasound-guided group but the difference did not reach statistical significance (P = 0.052 and P = 0.052). The first pass success rate was higher, total number of attempts required for access and time to sheath insertion were lower in the ultrasound-guided group. Atheromatous plaques on the common femoral artery, iliac artery obstructive lesion, previous ipsilateral puncture of the common femoral artery, obesity, and blood pressure during puncture did not change the outcome.

CONCLUSIONS

Ultrasound guidance improves secondary outcomes of the common femoral artery puncture when compared to palpation-guided puncture. Technical success and complication rates seem lower in the presence of ultrasound guidance but larger study populations are needed to verify the result.

Transjugular liver biopsy

Liver biopsy is considered the gold standard for the evaluation of acute and chronic liver disorders. Transjugular liver biopsy (TJLB) was described by Dotter in 1964 and clinically performed for the first time by Hanafee in 1967. TJLB consists of obtaining liver tissue through a rigid cannula introduced into one of the hepatic veins, typically using jugular venous access. The quality of the TJLB specimens has improved so much that the samples obtained by this method are comparable with those obtained with the percutaneous technique. TJLB is indicated for patients with coagulopathy, ascites, peliosis hepatis, morbid obesity, liver transplant, or in patients undergoing a transjugular intrahepatic portosystemic shunt procedure. The technical success rate for a TJLB procedure ranges from 87 to 97%. Sample fragmentation has been reported in 14 to 25% of the TJLB samples. The complication rates are low and range between 1.3% and 6.5%. The purpose of this article is to provide a review of the fundamental aspects of the TJLB procedure, including technique, indications, contraindications, results, and complications.

Opportunities of improvement in the management of pancreatic and periampullary tumors

Abstract Objective. The first objective of the present study was to identify opportunities of improvement for clinical practice, assessed by local quality indicators, then to analyze possible reasons why we did not reach defined treatment quality measures. The second objective was to characterize patients, considered unresectable according to present criteria, for future arrangement of interventional studies with improved patient selection. Material and methods. Prospective observational cohort study from October 2008 to December 2010 of patients referred to the authors' institution with suspected pancreatic or periampullary neoplasm. Results. Of 330 patients, 135 underwent surgery, 195 did not, 129 due to unresectable malignancies. The rest had benign lesions. Perioperative morbidity rate was 32.6%, mortality 0.7%. Radical resection (R0) was obtained in 23 (41.8%) of 55 patients operated for pancreatic adenocarcinoma and 6.3% underwent reconstructive vascular surgery. Diagnostic failure/delay resulted in unresectable carcinoma, primarily misconceived as serous cystic adenoma in two patients. One resected lesion turned out to be focal autoimmune pancreatitis. One case with misdiagnosed cancer was revised to be a pseudoaneurysm. Palliative treatment was offered to 144 patients with malignant tumors, 62 due to locally advanced disease and all pancreatic adenocarcinomas. Conclusions. Quality improvement opportunities were identified for patient selection and surgical technique: Too few patients underwent reconstructive vascular surgery. The most important quality indicators are those securing resectional, radical (R0) surgery. Altogether 143 patients (57.9%) of those with malignant tumors were found unresectable, most of these patients are eligible for inclusion in future interventional studies with curative and/or palliative intention.

How Safe is Eptifibatide during Urgent Carotid Artery Stenting?

Background: Glycoprotein IIB/IIIA inhibitors are occasionally utilized during carotid artery stenting (CAS) in the presence or absence of a visualized intra-operative thrombus.

Objective: We assess the hemorrhagic and clinical outcomes associated with the use of eptifibatide during CAS.

Methods: A retrospective analysis of prospectively collected data on patients with the diagnosis of carotid artery stenosis underwent CAS in a single center. We identified those who received intravenous eptifibatide intra-operatively and compared to the rest of the cohort. Hemorrhagic outcomes included intracerebral hemorrhage (ICH) or groin hematoma that occurred during the hospital stay.

Results: In this analysis, 81 patients had CAS during a 3-year span; 16 of those had received 15 mg of intravenous eptifibatide intra-operatively. The mean age of the treated and untreated patients was similar (65.6 ± 13.4 versus 65.4 ± 10.2; P = 0.13). One patient (1.2%) in this series had ICH in the perioperative period that occurred in the non-eptifibatide group. Five patients (6.2%) in this series had groin hematoma; only one in the non-eptifibatide group required surgical repair. No mortality was reported and clinical outcomes including discharge modified Rankin scale, NIH stroke scale, as well as discharge destination were similar in both groups. A stratified analysis among those who underwent an urgent CAS showed no significant differences in the risks of hemorrhages or any clinical outcome (P > 0.05).

Conclusion: The use of eptifibatide during CAS is safe. The risk of any hemorrhagic complication is rare in this series; however, a prospective study to validate this observation will be helpful.

Real-time multipoint gastrointestinal 19-fluorine catheter tracking

PURPOSE

To develop MR based real-time gastrointestinal 19-Fluorine (19F) catheter tracking and visualization allowing for real-time detection and feedback of 3D catheter shape and movement as well as catheter-driven adjustments of 1H imaging geometry parameters.

METHODS

Data were acquired on a 3T clinical system using 3D Golden Angle radial sampling. Two gastrointestinal catheters incorporating four fiducial 19F markers (65 or 50 µL marker volume) were tracked while being pulled through a gel phantom by an operator inside the MR room with velocities of 2-18 mm/s. During continuous acquisition, k-space profiles were transferred in real-time to an external computer for concurrent reconstruction of 3D 19F images and detection and visualization of marker positions. Based on αthe marker positions, automatic adjustments of 1H imaging planes to facilitate targeted anatomical scanning was implemented.

RESULTS

Mean tracking reliabilities were 94.5 and 83.6% (catheters 1 and 2) for temporal resolutions 185-740 ms. Reconstruction times of 196 ms were achieved. Real-time visual feedback allowed the operator to accurately control the catheter movement. Catheter-guidance for 1H imaging was reliable.

CONCLUSION

The presented real-time 19F MR based framework for the tracking of 19F labeled devices is applicable to combined 19F and 1H MRI guidance of gastrointestinal devices in vivo.

Safety and efficacy of ultrasound-guided fiducial marker implantation for CyberKnife radiation therapy

Objective

To evaluate the safety and technical success rate of an ultrasound-guided fiducial marker implantation in preparation for CyberKnife radiation therapy.

Materials and Methods

We retrospectively reviewed 270 percutaneous ultrasound-guided fiducial marker implantations in 77 patients, which were performed from June 2008 through March 2011. Of 270 implantations, 104 were implanted in metastatic lymph nodes, 96 were in the liver, 39 were in the pancreas, and 31 were in the prostate. During and after the implantation, major and minor procedure-related complications were documented. We defined technical success as the implantation enabling adequate treatment planning and CT simulation.

Results

The major and minor complication rates were 1% and 21%, respectively. One patient who had an implantation in the liver suffered severe abdominal pain, biloma, and pleural effusion, which were considered as major complication. Abdominal pain was the most common complication in 11 patients (14%). Among nine patients who had markers inserted in the prostate, one had transient hematuria for less than 24 hours, and the other experienced transient voiding difficulty. Of the 270 implantations, 261 were successful (97%). The reasons for unsuccessful implantations included migration of fiducial markers (five implantations, 2%) and failure to discriminate the fiducial markers (three implantations, 1%). Among the unsuccessful implantation cases, six patients required additional procedures (8%).

Conclusion

The symptomatic complications following ultrasound-guided percutaneous implantation of fiducial markers are relatively low. However, careful consideration of the relatively higher rate of migration and discrimination failure is needed when performing ultrasound-guided percutaneous implantations of fiducial markers.

Embolization of pulmonary AVMs of feeding arteries less than 3 mm: reports of two cases and an 8-year follow-up without embolization

Pulmonary arteriovenous malformations (PAVMs) with feeding arteries of 3 mm or more have been shown to be associated with paradoxical embolization and serious neurologic complications. Therefore it is generally recommended to occlude feeding arteries of this size, while smaller feeding arteries often are left untreated. However, neurologic complications have also been described in patients with small PAVMs, and it has not been possible to stratify risk by size of feeding artery and thus there is no evidence that 3 mm is the critical size of the feeding artery potentially giving complications. Further, it is well-known that with time PAVMs and their feeding arteries may enlarge. Also, embolization of small feeding arteries will minimize the risk of paradoxical emboli and reduce the need for CT follow-up controls in these patients. Two cases demonstrate the possibility to embolize small feeding arteries.

Technical note: Image guided internal fiducial placement for stereotactic radiosurgery (CyberKnife)

Internal gold fiducials are necessary for tracking the translational and rotational movements of target lesions during stereotactic radiosurgery. The fiducials are generally placed under image guidance in and around the lesions by interventional radiologists. Specific challenges are encountered during the procedure. This article discusses the basic principles and techniques as well as the specific complications.

Assessment of tumoricidal efficacy and response to treatment with 18F-FDG PET/CT after intraarterial infusion with the antiglycolytic agent 3-bromopyruvate in the VX2 model of liver tumor

The purpose of this study was to determine the effects of 3-bromopyruvate (3-BrPA) on tumor glucose metabolism as imaged with (18)F-FDG PET/CT at multiple time points after treatment and compare them with those after intraarterial control injections of saline.

METHODS

Twenty-three New Zealand White rabbits implanted intrahepatically with VX2 tumors were assigned to 1 of 2 groups: 14 rabbits were assigned to the treatment group (TG) and 9 to the saline control group (SG). All animals were infused with 25 mL of either 1.75 mM 3-BrPA or saline over 1 h via a 2-French catheter, which was secured in the hepatic artery. For PET/CT, the animals were injected with 37 MBq of (18)F-FDG at 1 d before treatment and 2 h, 24 h, and 1 wk after treatment. Tumor size, tumor and liver maximal standardized uptake value (SUV(max)), and tumor-to-background ratios were calculated for all studies. Seven TG and 5 SG animals were sacrificed at 1 wk after treatment for histopathologic analysis.

RESULTS

Intense (18)F-FDG uptake was seen in untreated tumors. A significant reduction in tumor SUV(max) was noted in TG animals, when compared with SG animals, at 1 wk after treatment (P = 0.006). The tumor-to-liver background ratio in the TG animals, compared with the SG animals, was significantly reduced as early as 24 h after treatment (P = 0.01) and remained reduced at 1 wk (P = 0.003). Tumor SUV(max) increased from the baseline levels at 7 d in controls (P = 0.05). The histopathologic analysis of explanted livers revealed increased tumor necrosis in all TG samples. There was a significant inverse correlation (r(2) = 0.538, P = 0.005) between the percentage of tumor necrosis on histopathology and tumor SUV(max) on (18)F-FDG PET at 7 d after treatment with 3-BrPA.

CONCLUSION

Intraarterial injection of 3-BrPA resulted in markedly decreased (18)F-FDG uptake as imaged by PET/CT and increased tumor necrosis on histopathology at 1 wk after treatment in the VX2 rabbit liver tumor. PET/CT appears to be a useful means to follow antiglycolytic therapy with 3-BrPA.

A descriptive comparison of ultrasound-guided central venous cannulation of the internal jugular vein to landmark-based subclavian vein cannulation

OBJECTIVES

The safest site for central venous cannulation (CVC) remains debated. Many emergency physicians (EPs) advocate the ultrasound-guided internal jugular (USIJ) approach because of data supporting its efficiency. However, a number of physicians prefer, and are most comfortable with, the subclavian (SC) vein approach. The purpose of this study was to describe adverse event rates among operators using the USIJ approach, and the landmark SC vein approach without US.

METHODS

This was a prospective observational trial of patients undergoing CVC of the SC or internal jugular veins in the emergency department (ED). Physicians performing the procedures did not undergo standardized training in either technique. The primary outcome was a composite of adverse events defined as hematoma, arterial cannulation, pneumothorax, and failure to cannulate. Physicians recorded the anatomical site of cannulation, US assistance, indications, and acute complications. Variables of interest were collected from the pharmacy and ED record. Physician experience was based on a self-reported survey. The authors followed outcomes of central line insertion until device removal or patient discharge.

RESULTS

Physicians attempted 236 USIJ and 132 SC cannulations on 333 patients. The overall adverse event rate was 22% with failure to cannulate being the most common. Adverse events occurred in 19% of USIJ attempts, compared to 29% of non-US-guided SC attempts. Among highly experienced operators, CVCs placed at the SC site resulted in more adverse events than those performed using USIJ (relative risk [RR] = 1.89, 95% confidence interval [CI] = 1.05 to 3.39).

CONCLUSIONS

While limited by observational design, our results suggest that the USIJ technique may result in fewer adverse events compared to the landmark SC approach.

Credentialing for radiology

Patients expect to receive safe, predictable and high-quality care delivered by competent professionals. Thus, it has become important to provide specific training in existing and new modalities and prove on-going clinical expertise. Hospital credentialing is the process by which the competence of a doctor is determined by the hospital management. In Australia, radiologists participate in a mandatory program of continuing professional development and are also required to maintain a logbook of procedures. The Conjoint Committee for the Recognition of Training in Peripheral Endovascular Therapy has been established to advise the respective subspecialty groups on the requirements for accreditation. This article examines some of the issues the committee has considered in preparing the criteria to assist institutions for the purposes of credentialing and gives an Australian perspective on future trends.

Electronic Healthcare Record and clinical research in cardiovascular radiology. HL7 CDA and CDISC ODM interoperability

Integrating clinical research data entry with patient care data entry is a challenging issue. At the G. Pompidou European Hospital (HEGP), cardiovascular radiology reports are captured twice, first in the Electronic Health Record (EHR) and then in a national clinical research server. Informatics standards are different for EHR (HL7 CDA) and clinical research (CDISC ODM). The objective of this work is to feed both the EHR and a Clinical Research Data Management System (CDMS) from a single multipurpose form. We adopted and compared two approaches. First approach consists in implementing the single "care-research" form within the EHR and aligning XML structures of HL7 CDA document and CDISC ODM message to export relevant data from EHR to CDMS. Second approach consists in displaying a single "care-research" XForms form within the EHR and generating both HL7 CDA document and CDISC message to feed both EHR and CDMS. The solution based on XForms avoids overloading both EHR and CDMS with irrelevant information. Beyond syntactic interoperability, a perspective is to address the issue of semantic interoperability between both domains.

Referenceless MR thermometry for monitoring thermal ablation in the prostate

Referenceless proton resonance frequency (PRF) shift thermometry provides a means to measure temperature changes during minimally invasive thermotherapy that is inherently robust to motion and tissue displacement. However, if the referenceless method is used to determine temperature changes during prostate ablation, phase gaps between water and fat in image regions used to determine the background phase can confound the phase estimation. We demonstrate an extension to referenceless thermometry which eliminates this problem by allowing background phase estimation in the presence of phase discontinuities between aqueous and fatty tissue. In this method, images are acquired with a multiecho sequence and binary water and fat maps are generated from a Dixon reconstruction. For the background phase estimation, water and fat regions are treated separately and the phase offset between the two tissue types is determined. The method is demonstrated feasibile in phantoms and during in vivo thermal ablation of canine prostate.

Real-time accelerated interactive MRI with adaptive TSENSE and UNFOLD

Reduced field-of-view (FOV) acceleration using time-adaptive sensitivity encoding (TSENSE) or unaliasing by Fourier encoding the overlaps using the temporal dimension (UNFOLD) can improve the depiction of motion in real-time MRI. However, increased computational resources are required to maintain a high frame rate and low latency in image reconstruction and display. A high-performance software system has been implemented to perform TSENSE and UNFOLD reconstructions for real-time MRI with interactive, on-line display. Images were displayed in the scanner room to investigate image-guided procedures. Examples are shown for normal volunteers and cardiac interventional experiments in animals using a steady-state free precession (SSFP) sequence. In order to maintain adequate image quality for interventional procedures, the imaging rate was limited to seven frames per second after an acceleration factor of 2 with a voxel size of 1.8 x 3.5 x 8 mm. Initial experiences suggest that TSENSE and UNFOLD can each improve the compromise between spatial and temporal resolution in real-time imaging, and can function well in interactive imaging. UNFOLD places no additional constraints on receiver coils, and is therefore more flexible than SENSE methods; however, the temporal image filtering can blur motion and reduce the effective acceleration. Methods are proposed to overcome the challenges presented by the use of TSENSE in interactive imaging. TSENSE may be temporarily disabled after changing the imaging plane to avoid transient artifacts as the sensitivity coefficients adapt. For imaging with a combination of surface and interventional coils, a hybrid reconstruction approach is proposed whereby UNFOLD is used for the interventional coils, and TSENSE with or without UNFOLD is used for the surface coils.

Real-time volume rendered MRI for interventional guidance

Volume renderings from magnetic resonance imaging data can be created and displayed in real-time with user interactivity. This can provide continuous 3D feedback to assist in guiding an interventional procedure. A system is presented which can produce real-time volume renderings from 2D multi-slice or 3D MR pulse sequences. Imaging frame rates up to 30 per second have been demonstrated with a latency of approximately one-third of a second, depending on the image matrix size. Several interactive capabilities have been implemented to enhance visualization such as cut planes, individual channel scaling and color highlighting, view sharing, saturation preparation, complex subtraction, gating control, and choice of alpha blending or MIP rendering. The system is described and some interventional application examples are shown. To view movies of some of the examples, enter the following address into a web browser: http://nhlbi.nih.gov/labs/papers/lce/guttman/rtvolmri/index/htm.

Techniques for fast stereoscopic MRI

Stereoscopic MRI can impart 3D perception with only two image acquisitions. This economy over standard multiplanar 3D volume renderings allows faster frame rates, which are needed for real-time imaging applications. Real-time 3D perception may enhance the appreciation of complex anatomical structures, and may improve hand-eye coordination while manipulating a medical device during an image-guided interventional procedure. To this goal, a system is being developed to acquire and display stereoscopic MR images in real-time. A clinically used, fast gradient-recalled echo-train sequence has been modified to produce stereo image pairs. Features have been added for depth cueing, view sharing, and bulk signal suppression. A workstation was attached to a clinical MR scanner for fast data extraction, image reconstruction and stereoscopic image display.