Fat-suppressed volume isotropic turbo spin echo acquisition (VISTA) MR imaging in evaluating radial and root tears of the meniscus: Focusing on reader-defined axial reconstruction

Objective

To assess the diagnostic value of fat-suppressed (FS) three-dimensional (3D) volume isotropic turbo spin echo acquisition (VISTA) imaging in detecting radial and root tears of the meniscus, including the reader-defined reformatted axial (RDA) plane.

Materials and methods

Twenty-three patients with arthroscopically confirmed radial or root tears of the meniscus underwent magnetic resonance imaging (MRI) with 2D and FS 3D VISTA sequences. MRIs were reviewed independently by two musculoskeletal radiologists blinded to the arthroscopic findings. Sensitivity, specificity, accuracy, and interobserver agreement were calculated for radial and root tears. Both radiologists reported confidence scale for the presence of meniscal tears in 2D axial imaging, 3D axial imaging, and RDA imaging, based on a five-point scale. Wilcoxon's signed rank test was used to compare confidence scale.

Results

The sensitivity, specificity, and accuracy of FS 3D VISTA MR imaging versus 2D MR imaging were as follows: 96%, 96%, and 96% versus 91%, 91%, and 91%, respectively in reader 1, and 96%, 96%, and 96% versus 83%, 91%, and 87%, respectively, in reader 2. Interobserver agreement for detecting meniscal tears was excellent (κ = 1) with FS 3D VISTA. The confidence scale was significantly higher for 3D axial images than 2D imaging (p = 0.03) and significantly higher in RDA images than 3D axial image in detecting radial and root tears.

Conclusions

FS 3D VISTA had a better diagnostic performance in evaluating radial and root tears of the meniscus. The reader-defined reformatted axial plane obtained from FS 3D VISTA MR imaging is useful in detecting radial and root tears of the meniscus.     

Qualitative and Quantitative Assessment of Isotropic Ankle Magnetic Resonance Imaging: Three-Dimensional Isotropic Intermediate-Weighted Turbo Spin Echo versus Three-Dimensional Isotropic Fast Field Echo Sequences

Objective

To compare the image quality of volume isotropic turbo spin echo acquisition (VISTA) imaging method with that of the three-dimensional (3D) isotropic fast field echo (FFE) imaging method applied for ankle joint imaging.

Materials and Methods

MR imaging of the ankles of 10 healthy volunteers was performed with VISTA and 3D FFE sequences by using a 3.0 T machine. Two radiologists retrospectively assessed the tissue contrast between fluid and cartilage (F-C), and fluid and the Achilles tendon (F-T) with use of a 4-point scale. For a quantitative analysis, signal-to-noise ratio (SNR) was obtained by imaging phantom, and the contrast ratios (CRs) were calculated between F-T and F-C. Statistical analyses for differences in grades of tissue contrast and CRs were performed.

Results

VISTA had significantly superior grades in tissue contrast of F-T (p = 0.001). Results of 3D FFE had superior grades in tissue contrast of F-C, but these result were not statistically significant (p = 0.157). VISTA had significantly superior CRs in F-T (p = 0.002), and 3D FFE had superior CRs in F-C (p = 0.003). The SNR of VISTA was higher than that of 3D FFE (49.24 vs. 15.94).

Conclusion

VISTA demonstrates superior tissue contrast between fluid and the Achiles tendon in terms of quantitative and qualitative analysis, while 3D FFE shows superior tissue contrast between fluid and cartilage in terms of quantitative analysis.     

Intracranial arterial wall imaging using three-dimensional high isotropic resolution black blood MRI at 3.0 Tesla

Purpose:

To develop a high isotropic‐resolution sequence to evaluate intracranial vessels at 3.0 Tesla (T).

Materials and Methods:

Thirteen healthy volunteers and 4 patients with intracranial stenosis were imaged at 3.0T using 0.5‐mm isotropic‐resolution three‐dimensional (3D) Volumetric ISotropic TSE Acquisition (VISTA; TSE, turbo spin echo), with conventional 2D‐TSE for comparison. VISTA was repeated for 6 volunteers and 4 patients at 0.4‐mm isotropic‐resolution to explore the trade‐off between SNR and voxel volume. Wall signal‐to‐noise‐ratio (SNR_wall), wall‐lumen contrast‐to‐noise‐ratio (CNR_wall‐lumen), lumen area (LA), wall area (WA), mean wall thickness (MWT), and maximum wall thickness (maxWT) were compared between 3D‐VISTA and 2D‐TSE sequences, as well as 3D images acquired at both resolutions. Reliability was assessed by intraclass correlations (ICC).

Results:

Compared with 2D‐TSE measurements, 3D‐VISTA provided 58% and 74% improvement in SNR_wall and CNR_wall‐lumen, respectively. LA, WA, MWT and maxWT from 3D and 2D techniques highly correlated (ICCs of 0.96, 0.95, 0.96, and 0.91, respectively). CNR_wall‐lumen using 0.4‐mm resolution VISTA decreased by 27%, compared with 0.5‐mm VISTA but with reduced partial‐volume‐based overestimation of wall thickness. Reliability for 3D measurements was good to excellent.

Conclusion:

The 3D‐VISTA provides SNR‐efficient, highly reliable measurements of intracranial vessels at high isotropic‐resolution, enabling broad coverage in a clinically acceptable time. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Value of three-dimensional T2-weighted turbo spin-echo imaging with tissue-specific variable refocusing flip angle for 3-T magnetic resonance imaging of prostate cancer: comparison with conventional two- and three-dimensional T2-weighted turbo spin-echo imaging

Purpose

To investigate the impact of three-dimensional (3D) T2-weighted turbo spin-echo imaging (TSE-T2WI) with tissue-specific variable refocusing flip angle (TS-VRFA) on image quality and prostate cancer (PCa) detection and extraprostatic extension (EPE) evaluation compared to 2D TSE-T2WI and conventional 3D TSE-T2WI with volume isotropic TSE acquisition (VISTA).

Materials and methods

Image data sets of 40 patients who underwent 3-T MRI before prostatectomy, including multiplane 2D T2WI, 3D T2WI with TS-VRFA and VISTA, and diffusion-weighted images were independently evaluated by two radiologists. The detectability of PCa and EPE of each sequence was assessed using areas by the receiver operating characteristic curve (AUC) analysis. Image quality measures and contrast ratios (CR) between cancerous lesions and non-cancerous regions for each T2WI were also evaluated.

Results

Overall image quality of TS-VRFA was better than that of VISTA and equivalent to 2D. The highest CR was obtained with TS-VRFA (P < 0.05). For both readers, no significances were observed in detectability for PCa detection between three sequences (P > 0.05). For both readers, there were no significant differences in AUC for EPE evaluation between three sequences (P > 0.05).

Conclusion

3D T2 WI using TS-VRFA could potentially replace multiplane 2D T2 WI for prostate cancer diagnosis with better image quality than VISTA.

     

Performance evaluation of the GE healthcare eXplore VISTA dual-ring small-animal PET scanner.

We evaluated the performance characteristics of the eXplore VISTA dual-ring small-animal PET scanner, a stationary, ring-type, depth-of-interaction (DOI) correcting system designed to simultaneously maximize sensitivity, resolution, and resolution uniformity over a field of view sufficient to image rodent-sized animals. METHODS: We measured the intrinsic spatial resolution response of the VISTA detector modules, spatial and volume resolution throughout a representative portion of the field of view, and imaged several common resolution phantoms to provide a qualitative picture of resolution performance. We obtained an axial sensitivity profile and measured central point source sensitivity, scatter fractions and noise equivalent count (NEC) rates for rat- and mouse-sized objects using different energy windows, and count rate linearity. In addition, we measured the energy and timing resolution of both of the crystal layers (cerium-doped gadolinium orthosilicate and cerium-doped lutetium-yttrium orthosilicate) that give VISTA machines a DOI compensation capability. We examined the effectiveness of this DOI compensation by comparing spatial resolution measurements with and without the DOI correction enabled. Finally, several animal studies were included to illustrate system performance in the field. RESULTS: Spatial and volume resolutions averaged approximately 1.4 mm and 2.9 mm(3), respectively (with 3-dimensional Fourier rebinning and 2-dimensional filtered backprojection image reconstructions and an energy window of 250-700 keV), along the central axis of the scanner, and the spatial resolution was better than 1.7 mm and 2.1 mm at 1 and 2 cm off the central axis, respectively. Central point source sensitivity measured approximately 4% with peak NEC rates of 126.8 kcps at 455 kBq/mL and 77.1 kcps at 141 kBq/mL for mouse- and rat-sized uniform, cylindric phantoms, respectively. The radial spatial resolution at 2.8 cm off axis with DOI compensation was 2.5 mm but degraded (by 56%) to 3.9 mm without DOI compensation (as would be the case with a geometrically identical scanner without DOI correction capability). CONCLUSION: These results indicate that the VISTA small-animal PET scanner is well suited to imaging rodent-sized animals. The combination of high spatial resolution, resolution uniformity, sensitivity, and count rate performance, made possible in part by the novel use of phoswich detector modules, confers significant technical advantages over machines with similar geometry but without DOI correction capability.     

Criterion-related validity of four clinical tests used to measure hamstring flexibility in professional futsal players

Objective

To examine the criterion related validity of the sit-and-reach test (SR), toe touch test (TT), modified sit-and-reach test (MSR) and back-saver sit-and-reach test (BSSR) for estimating hamstring flexibility measured through the passive straight leg raise test (PSLR) in professional futsal players.

Design

Correlation laboratory study.

Setting

Controlled laboratory environment.

Participants

One hundred and three futsal players (55 males age 26 ± 4 years, 48 females age 23 ± 5 years).

Main outcome measures

Two trials of SR, TT, MSR, BSSR (left and right) and PSLR right and left (hamstring criterion measure) in a randomized order.

Results

Regression analysis was performed to examine the association of SR, TT, MSR and BSSR with PSLR in both males and females separately. In males, only MSR test had moderate association criterion with PSLR (R² = 0.57). In females, SR (R² = 0.86), TT (R² = 0.85), MSR (R² = 0.53) and average BSSR (R² = 0.82) were associated with PSLR.

Conclusions

SR, TT, MSR and BSSR had moderate criterion related validity for estimating hamstring flexibility in female but not male professional futsal players. The authors recommend that researchers, clinicians, and physical therapists adopt one angular test as a measure of hamstring muscle length in futsal players.     

Analysis of acetabular version in the native hip: comparison between 2D axial CT and 3D CT measurements

Objective  

To compare two-dimensional (2D) axial with three-dimensional (3D) computerized tomography (CT) measurements of acetabular version in native hips.     

Partial tear of the anterior cruciate ligament of the knee: injury patterns on MR imaging

Purpose  

To describe rupture patterns of partial anterior cruciate ligament (ACL) tears on magnetic resonance (MR) imaging.     

MR imaging of the brachial plexus: comparison between 1.5-T and 3-T MR imaging: preliminary experience

Objective  

To compare 1.5-T and 3-T magnetic resonance (MR) imaging of the brachial plexus.     

Computed tomography angiography of the carotid arteries at low kV settings: a prospective randomised trial assessing radiation dose and diagnostic confidence

Objective  

To assess radiation dose and diagnostic image quality of a low-dose (80 kV) versus a standard-dose (120 kV) protocol for computed tomography angiography (CTA) of the supra-aortic arteries.     

Diffusion tensor imaging applications in multiple sclerosis patients using 3T magnetic resonance: a preliminary study

Objectives  

This study evaluated patients with multiple sclerosis using diffusion tensor imaging (DTI) to obtain fractional anisotropy (FA) and mean diffusivity (MD) values.     

Prompt-gamma compensation in Rb-82 myocardial perfusion 3D PET/CT

Objective  

To compare the diagnostic accuracy of Rb-82 myocardial perfusion three-dimensional (3D) PET with and without prompt-gamma compensation (PGC).     

Characteristic magnetic resonance features of focal autoimmune pancreatitis useful for differentiation from pancreatic cancer

Purpose  

To identify characteristic magnetic resonance (MR) features of focal autoimmune pancreatitis (f-AIP) useful for differentiation from pancreatic cancer (PC).     

Imaging findings of intravascular papillary endothelial hyperplasia presenting in extremities: correlation with pathological findings

Objective  

To describe magnetic resonance imaging (MRI) and ultrasound (US) findings of intravascular papillary endothelial hyperplasia (IPEH) arising in extremities.     

Intra-individual comparison of different contrast media concentrations (300 mg, 370 mg and 400 mg iodine) in MDCT

Objective  

To compare intra-individual contrast enhancement in multi-detector-row computed tomography (MDCT) using contrast media (CM) containing 300, 370 and 400 mg iodine per ml (mgI/ml).     

Percutaneous stereotactic radiofrequency ablation of colorectal liver metastases

Objectives  

To evaluate the outcome of patients with colorectal liver metastasis (CRLM) treated with stereotactic radiofrequency ablation (SRFA).     

One-to-one comparison between digital spot compression view and digital breast tomosynthesis

Objective  

To assess if digital breast tomosynthesis (DBT) is at least equal to digital spot compression view (DSCV).     

Predictive value of diffusion-weighted magnetic resonance imaging during chemoradiotherapy for head and neck squamous cell carcinoma

Objective  

To evaluate diffusion-weighted (DWI) magnetic resonance imaging (MRI) for treatment prediction during chemoradiotherapy (CRT) of head and neck squamous cell carcinoma (HNC).     

Magnetic resonance angiography (MRA) of the calf station at 3.0 T: intraindividual comparison of non-enhanced ECG-gated flow-dependent MRA, continuous table movement MRA and time-resolved MRA

Objectives  

To compare 3D non-enhanced ECG-gated inflow-dependent MRA (NE-MRA) vs. continuous table movement (CTM) MR-angiography and time-resolved TWIST-MRA in the calf station at 3.0 T in a clinical patient collective.     

Prediction of range of motion 2?years after mobile-bearing total knee arthroplasty: PCL-retaining versus PCL-sacrificing

Purpose  

This study evaluated the changes in the range of motion (ROM) with time postoperatively.