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At least 361 records · Page 20Linked to original sources
PubMed2005

Does new magnetic resonance imaging technology provide better geometrical accuracy during stereotactic imaging?

OBJECT: The authors sought to compare the accuracy of stereotactic target imaging using the Siemens 1T EXPERT and 1.5T SYMPHONY magnetic resonance (MR) units. METHODS: A water-filled cylindrical Perspex phantom with axial and coronal inserts containing grids of glass rods was fixed in the Leksell stereotactic frame and subjected to MR imaging in Siemens 1T EXPERT and Siemens 1.5T SYMPHONY units. Identical sequences were used for each unit. The images were transferred to the GammaPlan treatment planning system. Deviations between stereotactic coordinates based on MR images and estimated real geometrical positions given by the construction of the phantom insert were evaluated for each study. The deviations were further investigated as a function of the MR unit used, MR sequence, the image orientation, and the spatial position of measured points in the investigated volume. CONCLUSIONS: Larger distortions were observed when using the SYMPHONY 1.5T unit than those with the EXPERT 1T unit. Typical average distortion in EXPERT 1T was not more than 0.6 mm and 0.9 mm for axial and coronal images, respectively. Typical mean distortion for SYMPHONY 1.5T was not more than 1 mm and 1.3 mm for axial and coronal images, respectively. The image sequence affected the distortions in both units. Coronal T2-weighted spin-echo images performed in subthalamic imaging produced the largest distortions of 2.6 mm and 3 mm in the EXPERT 1T and SYMPHONY 1.5T, respectively. Larger distortions were observed in coronal slices than in axial slices in both units, and this effect was more pronounced in SYMPHONY 1.5T. Noncentrally located slice positions in the investigated volume of the phantom were associated with larger distortions.

Equipment Design↗
PubMed2004

FDG-PET for evaluation of recurrent lymph node metastases in patients with surgically resected breast cancer: adding spot images to whole body images.

BACKGROUND: To evaluate the role of 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET), spot images were added to whole-body FDG-PET images in a patient with suspected lymph node recurrence of breast cancer. METHODS: FDG-PET spot images were obtained of 44 patients who had undergone surgical resection of breast cancer as were whole-body FDG-PET images. A total of 33 lesions in 19 patients (mean age, 59 years; range, 39-70 years) were diagnosed as lymph node recurrence clinically, and standardized uptake values (SUVs) were calculated for whole body images and spot images. Lesions were also scored from 1 (not clear) to 3 (very clear) for both the whole body and spot images. RESULTS: For mediastinal lymph node metastases, the SUVs of the spot images (SUVsp) (mean, 4.0; range, 2.1-6.6) were significantly higher than the SUVs of the whole body images (SUVwb) (mean, 3.3; range, 2.1-5.8). For other lymph node metastases (neck, axilla, etc.), there was no significant difference between SUVwb (2.6; 1.4-6.5) and SUVsp (2.8; 1.6-8.1). CONCLUSIONS: By adding spot images, the evaluation of lymph node metastases became easier. Adding spot images to whole-body FDG-PET may be useful.

Adult↗
PubMed1998

Impact of filmless imaging on the frequency of clinician review of radiology images.

The purpose of this study was to determine the impact of filmless imaging on the frequency with which physicians access radiology images and to assess clinician perception of image accessibility using a hospital-wide Picture Archival and Communication System (PACS). Quantitative data were collected at the Baltimore VA Medical Center (BVAMC), prior to and after conversion to filmless imaging, to determine the frequency with which clinicians access radiology images. Survey data were also collected to assess physician preferences of image accessibility, time management, and overall patient care when comparing filmless and film-based modes of operation. In general, there was a significant increase in the average number of radiology images reviewed by clinicians throughout the hospital. However, the one are in the hospital where this trend was not observed was in the intensive care unit (ICU), where the frequency of image assess was similar between film and filmless operations. Ninety-eight percent of clinicians surveyed reported improved accessibility of images in a filmless environment resulting in improved time management. The mean clinician estimate of time saved due to the use of PACS was 44 minutes. The study documented a combination of clinician perception of improved accessibility and substantial time savings with the use of a hospital-wide PACS, which was supported by objective measurements. The increased frequency of image review by clinicians and rapid image access should provide a further impetus to radiologists to decrease report turnaround time to provided "added value" for patient care.

Baltimore↗
PubMed2002

Challenges in image acquisition and distribution for clinical image service.

We have developed a centralized application for acquiring images from multiple picture archiving and communication systems (PACS) and distributing images to a clinical image web server and other repositories. Our flexible strategy addresses a number of administrative challenges associated with delivering images into clinical, research, and test environments. DICOM images flow from PACSs and modalities to a UNIX-based "distributor" application, which relays them to one or more destinations. Image volume and transmission times were collected and analyzed. Three distributors receive an average of 34 gigabytes of image data per day. Images are sent concurrently to two web-based image servers, one used clinically by physicians and one used for testing. Transmission of certain classes of studies is prioritized for key physician groups. Delivery to research systems is also supported. Acquiring images from multi-vendor PACS for distribution to a web server for clinical image viewing is a challenging task. Centralizing the acquisition and distribution process reduces both the administrative effort and the impact on clinical operations associated with maintaining dynamic clinical, testing, and research environments.

Computer Communication Networks↗
PubMed2006

Error images for spectroscopic imaging by LCModel using Cramer-Rao bounds.

The results of spectroscopic imaging (SI) measurements are often presented as metabolic images. If the spectra quality is not sufficient, the calculated concentrations are biased and the metabolic images show an incorrect metabolite distribution. To simplify the quality analysis of spectra measured by SI, an error image, reflecting the accuracy of the computed concentrations, can be displayed along with the metabolite image. In this paper the relevance of Cramer-Rao bounds (CRBs) calculated by the LCModel program to describe errors in estimated concentrations is validated using spectra simulations. The relation between the average CRBs and standard deviations (STD) of metabolite concentrations from 100 simulated spectra for various signal to noise ratio and line broadening conditions is evaluated. A parameter for calculating error images for metabolite ratios is proposed and an effective way to display error images is shown. The results suggest that the average CRBs are strongly correlated with the standard deviations and hence that CRB values reflect the relative uncertainty of the calculated concentrations. The error information can be integrated directly into a metabolite image by displaying only those areas of the metabolite image with corresponding CRBs below a selected threshold or by mapping CRBs as a transparency of the metabolite image. The concept of error images avoids extensive examination of each SI spectrum and helps to reject low quality spectra.

Algorithms↗
PubMed1995

Mental scanning of visual images generated from verbal descriptions: towards a model of image accuracy.

Recent mental scanning experiments have shown that subjects are not only able to construct mental images from verbal descriptions, but that these images have structural properties similar to those of images derived from perception. In addition, the specific sequencing of a description can affect the internal structure of images of described objects, in particular their metric properties. Discontinuous descriptions require additional exposure to achieve the structural coherence of images constructed from continuous descriptions. Thus, the capacity of images to reflect accurately the objects they refer to is not an all-or-nothing property, but rather results from stepwise elaboration. This study describes a quantitative model designed to account for the gradual process of image elaboration and the progressive increase in image accuracy. The model posits that the location of a landmark mentioned in a description is not represented as a sharp point in the mental image, but is instead associated with a region around this point. Learning the description essentially consists of progressively narrowing each 'region of uncertainty' associated with a landmark to its exact location. Additional experimental data were collected to provide a more finegrained understanding of image elaboration. Computations of the regions of uncertainty associated with each landmark were used to develop a computer program simulating the whole mental scanning protocol, which provided support for our account of image accuracy.

Adult↗
PubMed1994

Fluorescence lifetime imaging microscopy: homodyne technique using high-speed gated image intensifier.

In the previous sections we demonstrated imaging of intracellular Ca2+ using our approach to FLIM. What other analytes can be imaged using FLIM? We have now characterized the lifetime of a good number of ion indicators. Based on these studies we know that Cl- can be imaged using FLIM with probes such as SPQ or MQAE, pH can be imaged using resorufin and probes of the SNAFL and SNARF (Molecular Probes) series, and Mg2+ can be imaged using Magnesium Green, Mag-quin-2, or Mag-quin-1 (Molecular Probes). At present, the probe for K+, as PBFI, are just adequate as a lifetime probe, but it seems likely that newer probes for Na+ (Sodium Green) and K+ will be practical for effective imaging. Of course, imaging of oxygen is possible using a wide variety of fluorophores. It should be noted that a wide variety of substances and/or phenomena are known to alter decay times, acting as quenchers. These include the phenomena of resonance energy transfer, collisional quenching, temperature effects, and viscosity effects. Also, the FLIM method is not limited to microscopic objects but can be possibly used in remote imaging of any object. Hence, FLIM will allow the imaging of the chemical and physical properties of objects based on the effects of the local environment on the decay kinetics of fluorophores. The instrumentation for FLIM is presently complex and requires a moderately complex laser source, a gain-modulated image intensifier, and a slow-scan CCD camera. However, one can readily imagine the instrumentation becoming rather compact, and even all solid-state, owing to advances in laser and CCD technologies and, more importantly, advances in probe chemistry. To be specific, the dye laser shown in Fig. 1 may be replaced by a simpler UV laser, such as the 354 nm HeCd laser which has become available (Fig. 11). Intensity modulation of a continuous wave sources can be accomplished with acoustooptic modulators. The scientific slow-scan CCD cameras are presently rather expensive, but they are used in the present instrumentation because of their linearity and high dynamic range. However, the increasing use of CCD detectors suggest that even the scientific-grade CCD cameras will soon become less costly. Additionally, the frame rates of these detectors continue to increase in response to the need for faster imaging. Furthermore, the performance of the video CCD cameras is increasing, as seen by the introduction of 10-bit video analog-to-digital (A/D) converters.(ABSTRACT TRUNCATED AT 400 WORDS)

Aminoquinolines↗
PubMed2000

Intravascular ultrasound imaging after cardiac transplantation: advantage of multi-vessel imaging.

BACKGROUND: Intravascular ultrasound is a sensitive tool to study transplant vasculopathy. However, there is no consensus regarding the methodology for imaging protocol. The impact of single versus multiple epicardial vessel imaging in determining the prevalence of transplant vasculopathy has not been determined. This study examines the benefit of three-vessel imaging versus one-vessel imaging in detecting transplant vasculopathy. METHODS AND RESULTS: One hundred eleven transplant recipients with intravascular ultrasound imaging at baseline (within 2 months of transplantation) were studied: 107 at 1-year, 53 at 2-year and 41 at 3-year follow-up. A total of 222 arteries, 519 segments and 772 sites were analyzed (94 LAD, 65 LCX and 65 RCA). The prevalence of transplant vasculopathy lesions was 27%, 41% and 58% at 1 year, 39%, 55% and 71% at 2 years and 39%, 55% and 74% at 3 years for patients with one-, two- and three-vessel imaging, respectively. Single- or two-vessel disease was present in 23% (7) and 32% (10) patients with three-vessel imaging, leading to the potential mislabeling of these 17 (55%) patients as "disease free" if they underwent only single-vessel imaging. CONCLUSIONS: Multivessel imaging is more sensitive in detecting the transplant vasculopathy lesions compared to single-vessel imaging. This important variable should be considered when designing and interpreting trials utilizing intravascular imaging derived end-point.

Adult↗
PubMed1995

Computerized detection of masses from digitized mammograms: comparison of single-image segmentation and bilateral-image subtraction.

RATIONALE AND OBJECTIVES: Two methods--single-image segmentation and bilateral-image subtraction--have been used commonly as the first stage in computer-aided detection (CAD) schemes to detect masses on digitized mammograms. In the current study, we investigated and compared the advantages and disadvantages of the two methods in achieving a high sensitivity for mass detection. METHODS: Two CAD schemes were tested. One used Gaussian filtering based on single-image segmentation, and the other used bilateral-image subtraction based on left-right image pairs to identify suspicious mass regions. A clinical database that contained 152 verified mass cases was used to compare the two approaches. RESULTS: The single-image segmentation method yielded 100% sensitivity and had a somewhat higher number of initial suspicious regions. The bilateral-image subtraction method missed several true-positive regions at the initial phase. Each approach achieved more than 90% sensitivity at a false-positive rate of approximately 0.8 per image. CONCLUSION: Optimal initial image segmentation schemes may depend on the complete detection and classification method used. Single-image segmentation methods may perform comparably with bilateral-image segmentation schemes, and these techniques appear to be more versatile and easily adaptable to future clinical CAD applications.

Breast Neoplasms↗
PubMed1998

Computational imaging of cerebral perfusion by real time processing of DSA images. Clinical applications.

Real time and high resolution functional imaging of cerebral perfusion was developed, which displays the color coded image of the cerebral perfusion index (PI) from the serial images of digital subtraction angiography (DSA). The small (3 x 3 pixels) regions of interest (ROI) were set on the images, and the time density curves of the contrast media for each ROI were obtained. The perfusion indices, corresponding to the mean transit time (MTT), were calculated for all the ROIs on the image in real time (5 sec) by the area over height method and then, converted to the PI image. A large ROI (64 x 64 pixels) was also used to estimate the parenchymal perfusion. In the normal subjects, consistent PI values at the various parts of the cerebral arteries were obtained, which reasonably agreed with the published values when converted to the blood flow. Then the study on the pathological subjects were made. Firstly, the alteration in the PI images agreed well with the CBF SPECT study in the case of moyamoya disease with the synangiosis operation. Secondly, even a 5% change of the parenchymal perfusion could be detected with the PI imaging, which was obscure when inspecting the series of DSA images, in the case of intra-arterial papaverine infusion for delayed vasospasm. Thirdly, the vortex inside a large aneurysm could be estimated with the same resolution as DSA. Our method offers real time, high resolution, projection angle independent and semiquantitative imaging of the cerebral perfusion from the conventional DSA images without introducing any new expensive devices. This method could be used to evaluate the therapeutic change and especially to monitor the rapidly changing cerebral perfusion in interventional angiography.

Aged↗
PubMed2005

Imaging melanoma in a murine model using reflectance-mode confocal scanning laser microscopy and polarized light imaging.

The light-scattering properties of cutaneous tissues provide optical contrast for imaging the presence and depth of pigmented melanoma in a highly pigmented murine model, the C57/B6 mouse. Early lesions are difficult to identify when viewing black lesions on a black mouse. Two methods were used to image early lesions in this model. (1) A reflectance-mode confocal scanning laser microscope (rCSLM) was built to provide horizontal images (x-y at depth z) and transverse images (x-z at position y) non-invasively in the living mouse. (2) A polarized light imaging (PLI) camera was built using a linearly polarized white light source that viewed the skin through an analyzing linear polarizer oriented either parallel or perpendicular to the illumination's polarization to yield two images, "PAR" and "PER," respectively. The difference image, PAR-PER, eliminated multiply scattered light and yielded an image of the superficial but subsurface tissues based only on photons scattered once or a few times so as to retain their polarization. rCSLM could image melanoma lesions developing below the epidermis. PLI could distinguish superficial from deeper melanoma lesions because the melanin of the superficial lesions attenuated the PAR-PER image, whereas deeper lesions failed to attenuate the PAR-PER image.

Animals↗
PubMed2005

Application of clinical scanners in rats: experimental carotid imaging using magnetic resonance imaging, spiral computed tomography, and color duplex ultrasound.

BACKGROUND AND PURPOSE: Noninvasive small animal imaging allows for reduction of the required numbers of animals in research by providing the possibility of long-term follow-up at various time points. Additionally, correlation to the investigated respective human disease is possible as equivalent equipment is employed. The authors therefore evaluate feasibility and potential of color duplex sonography, computed tomography angiography (CTA), and magnetic resonance angiography (MRA) by the use of clinical scanners for carotid artery imaging in rats. METHODS: Male Wistar rats (n = 17) were subjected to color duplex sonography, CTA, and MRA of the common carotid artery (CCA) and the carotid bifurcation. Clinical scanners were used for the experiments and optimal parameter settings evaluated accounting for the different size of the animals. The applied imaging methods were analyzed in regard to image quality and practicability in laboratory settings. RESULTS: The CCA could be clearly displayed by all imaging modalities in all rats. Duplex sonography provided distinct images and reproducible basic functional information. CTA and MRA provided distinct images of the CCA and the carotid bifurcation in both axial and reconstructed 3-dimensional images. The authors further describe different indications for these imaging methods regarding spatial resolution, acquisition times, possible scanning range, and application of contrast agent. CONCLUSIONS: Color duplex sonography, CTA, and MRA are all feasible methods for imaging of the carotid arteries in rats. Images of sufficient clarity and resolution could be obtained by the use of clinical scanners, yielding information about vessel size, direction of blood flow, and adjacent structures. Further studies need to be performed that address investigations of pathological conditions such as flow disturbances or vessel stenosis.

Animals↗
PubMed2000

The influence of different technique factors on image quality of lumbar spine radiographs as evaluated by established CEC image criteria.

In this study we have investigated the image quality of lumbar spine radiographs taken after recording technical and physical parameters. Two technical parameters were altered, tube voltage (70 kV and 90 kV for the anteroposterior (AP) projection and 77 kV and 95 kV for the lateral projection) and sensitivity of the film-screen system (sensitivity class 400 and 600). In total, 85 images were included in the study. Entrance surface dose (ESD) was measured using thermoluminescent dosemeters. The mean value of ESD for the different technique groups varied between 1.9 mGy (90 kV, sensitivity class 400) and 4.6 mGy (70 kV, sensitivity class 400) for the AP projection, and between 6.4 mGy (95 kV, sensitivity class 600) and 20.4 mGy (70 kV, sensitivity class 400) for the lateral projection. Image criteria given in the "European Guidelines on Quality Criteria for Radiographic Images" were used to assess image quality. Two evaluation methods have been employed. A straightforward scoring of fulfilled image criteria, and visual grading analysis using the structures defined in the image criteria. The latter method provided a sharper distinction between groups of images taken using different radiographic techniques. The average number of fulfilled image criteria for the AP projections varied between 0.74 (90 kV, sensitivity class 400) and 0.87 (70 kV, sensitivity class 400). For the lateral projection this number varied between 0.79 (95 kV, sensitivity class 600) and 0.84 (77 kV, sensitivity class 600). This study shows that image criteria are useful tools in clinical studies of image quality.

Adolescent↗
PubMed2000

Java-based remote viewing and processing of nuclear medicine images: toward "the imaging department without walls".

UNLABELLED: In nuclear medicine practice, images often need to be reviewed and reports prepared from locations outside the department, usually in the form of hard copy. Although hard-copy images are simple and portable, they do not offer electronic data search and image manipulation capabilities. On the other hand, picture archiving and communication systems or dedicated workstations cannot be easily deployed at numerous locations. To solve this problem, we propose a Java-based remote viewing station (JaRViS) for the reading and reporting of nuclear medicine images using Internet browser technology. METHODS: JaRViS interfaces to the clinical patient database of a nuclear medicine workstation. All JaRViS software resides on a nuclear medicine department server. The contents of the clinical database can be searched by a browser interface after providing a password. Compressed images with the Java applet and color lookup tables are downloaded on the client side. This paradigm does not require nuclear medicine software to reside on remote computers, which simplifies support and deployment of such a system. To enable versatile reporting of the images, color tables and thresholds can be interactively manipulated and images can be displayed in a variety of layouts. Image filtering, frame grouping (adding frames), and movie display are available. Tomographic mode displays are supported, including gated SPECT. RESULTS: The time to display 14 lung perfusion images in 128 x 128 matrix together with the Java applet and color lookup tables over a V.90 modem is <1 min. SPECT and PET slice reorientation is interactive (<1 s). JaRViS could run on a Windows 95/98/NT or a Macintosh platform with Netscape Communicator or Microsoft Intemet Explorer. The performance of Java code for bilinear interpolation, cine display, and filtering approaches that of a standard imaging workstation. CONCLUSION: It is feasible to set up a remote nuclear medicine viewing station using Java and an Internet or intranet browser. Images can be made easily and cost-effectively available to referring physicians and ambulatory clinics within and outside of the hospital, providing a convenient alternative to film media. We also find this system useful in home reporting of emergency procedures such as lung ventilation-perfusion scans or dynamic studies.

Humans↗
PubMed1997

Imaging of axonal damage in multiple sclerosis: spatial distribution of magnetic resonance imaging lesions.

We performed magnetic resonance imaging and magnetic resonance spectroscopic imaging on 28 patients with multiple sclerosis stratified for disability and clinical course (relapsing with at least partial remissions or secondary progressive disease). Lesions were segmented on the conventional proton density and T2-weighted magnetic resonance images, and lesion distribution images were generated for, each patient. The conventional magnetic resonance and spectroscopic images were transformed into a standard brain-based stereotaxic coordinate space, allowing comparison of images from different patients on a voxel-by-voxel basis. The spatial distribution of lesions in the transformed magnetic resonance images did not differ significantly between the relapsing and the progressive disease groups. We then generated from the individual data sets, group lesion probability distribution images for the relapsing and the progressive disease groups. The spatial distribution of metabolites was characterized with respect to lesion distribution using the magnetic resonance spectroscopic images transformed into stereotaxic space and averaged. The neuronal marker N-acetylaspartate was diffusely lower in the multiple sclerosis patients than in normal control subjects. Comparison of the averaged metabolite and T2-weighted lesion probability images confirmed loss of N-acetylaspartate in regions of both high and low lesion probability. This suggests that diffuse axonal volume loss or dysfunction extends beyond the inflammatory lesions of multiple sclerosis, perhaps due to microscopic disease or wallerian degeneration along projection pathways of axons traversing the lesions.

Adult↗
PubMed2004

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.

Adult↗
PubMedDate not supplied

Motion artifact in T2-weighted fast spin-echo images of the liver: effect on image contrast and reduction of artifact using respiratory triggering in normal volunteers.

The purpose of our study was to evaluate the effect of respiratory motion on the image contrast of T2-weighted fast spin-echo (FSE) images of the liver as well as the reduction of motion artifact using respiratory triggering of the data acquisition. We imaged the livers of 10 healthy volunteers using a fast spin-echo T2-weighted sequence. Images were obtained both without and with patient triggering. Triggered images were acquired in a segmented fashion during multiple sequential breath-holds using an echo train of 8 or 16, both with and without flow compensation (gradient moment nulling). Ratios of signal difference to noise (SD/N) of the liver and gallbladder as well as the liver and spleen were compared for all sequences. All of the triggered images showed statistically significant improvement of SD/N for the liver and gallbladder as well as for the liver and spleen when compared with the nontriggered images. Triggered images obtained with an echo train length of 8 and, with flow compensation, showed the highest SD/N ratios. In one volunteer whose liver contained multiple small cysts, the triggered images showed improved visualization of individual cysts and identified a larger number of cysts. Respiratory motion causes a significant loss of contrast on T2-weighted fast spin-echo images of the liver. This can be reduced by using a segmented data acquisition triggered by the respiratory cycle obtained during sequential breath-holds.

Adult↗
PubMed2004

High-resolution MR-imaging of the liver with T2-weighted sequences using integrated parallel imaging: comparison of prospective motion correction and respiratory triggering.

PURPOSE: To compare high-resolution T2-weighted images of the liver with and without integrated parallel acquisition techniques (iPAT) using either breath-hold sequences in combination with prospective acquisition motion correction (PACE) or respiratory triggering. MATERIALS AND METHODS: Ten volunteers and 10 patients underwent each four different high-resolution fast spin echo (FSE) T2-weighted sequences with 5 mm slice thickness and a full 320 matrix: a multi-breath-hold FSE sequence with and without iPAT and PACE and a respiratory-triggered FSE sequence with and without iPAT. Image quality was rated with a five-point scale by two independent readers. Signal intensity measurements were performed on a water phantom. RESULTS: The sequences with iPAT required a substantially shorter acquisition time without loss of image quality. Overall image quality was rated equal for all sequences by both readers. Image time for nine slices with iPAT was 13 seconds (19 seconds without iPAT) with multi-breath-hold and on average 4:00 minutes (7:02 minutes without iPAT) with respiratory triggering. Imaging with the PACE technique resulted in more correct positioning of the image stacks. CONCLUSION: T2-weighted fast imaging with iPAT is feasible and results in high-quality images within a short acquisition time. Overall image quality is not negatively affected by iPAT.

Adult↗