Turbo Spin-echo Diffusion-weighted Imaging Research Articles

Comparison of Echo Planar and Turbo Spin Echo Diffusion-Weighted Imaging in Intraoperative MRI.

Diffusion-weighted imaging (DWI) is routinely used in brain tumor surgery guided by intraoperative MRI (IoMRI). However, conventional echo planar imaging DWI (EPI-DWI) is susceptible to distortion and artifacts that affect image quality. Turbo spin echo DWI (TSE-DWI) is an alternative technique with minimal spatial distortions that has the potential to be the radiologically preferred sequence. To compare via single- and multisequence assessment EPI-DWI and TSE-DWI in the IoMRI setting to determine whether there is a radiological preference for either sequence. Retrospective. Thirty-four patients (22 female) aged 2-61 years (24 under 18 years) undergoing IoMRI during surgical resection of intracranial tumors. 3-T, EPI-DWI, and TSE-DWI. Patients were scanned with EPI- and TSE-DWI as part of the standard IoMRI scanning protocol. A single-sequence assessment of spatial distortion and image artifact was performed by three neuroradiologists blinded to the sequence type. Images were scored regarding distortion and artifacts, around and remote to the resection cavity. A multisequence radiological assessment was performed by three neuroradiologists in full radiological context including all other IoMRI sequences from each case. The DWI images were directly compared with scorings of the radiologists on which they preferred with respect to anatomy, abnormality, artifact, and overall preference. Wilcoxon signed-rank tests for single-sequence assessment, weighted kappa for single and multisequence assessment. A P-value <0.001 was considered statistically significant. For the blinded single-sequence assessment, the TSE-DWI sequence was scored equal to or superior to the EPI-DWI sequence for distortion and artifacts, around and remote to the resection cavity for every case. In the multisequence assessment, all radiologists independently expressed a preference for TSE-DWI over EPI-DWI sequences on viewing brain anatomy, abnormalities, and artifacts. The TSE-DWI sequences may be favored over EPI-DWI for IoMRI in patients with intracranial tumors. 2 TECHNICAL EFFICACY: Stage 5.

Localization Evaluation of Primary Middle Ear Cholesteatoma With Fusion of Turbo Spin-Echo Diffusion-Weighted Imaging and High-Resolution Computed Tomography.

The aim of the study is to evaluate the application of high-resolution computed tomography (HRCT) and turbo spin-echo diffusion-weighted imaging (TSE-DWI) fusion imaging for localization of middle ear cholesteatomas. Eighty-six patients with clinically suspected middle ear cholesteatomas were enrolled prospectively. Ear TSE-DWI and HRCT scans were performed using a postprocessing workstation to generate a TSE-DWI-CT fusion image. Subsequently, all the enrolled patients received surgical treatment. According to the STAM system (difficult access sites [S], the tympanic cavity [T], the attic [A], and the mastoid [M]), the agreement between the localization of lesions evaluated by HRCT, TSE-DWI, and TSE-DWI-CT fusion images and the intraoperatively recorded localization were computed using Cohen κ statistic. Based on the pathological results, the enrolled patients were divided into a cholesteatoma (n = 50) and a noncholesteatoma group (n = 36). The area under the receiver operator characteristic curve for diagnosis of cholesteatoma with TSE-DWI-CT fusion imaging was identical to that using the TSE-DWI images (0.924 vs 0.924, P > 0.05), but was significantly higher than that with HRCT imaging (0.924 vs 0.767, P = 0.0005). Furthermore, the diagnostic sensitivity and specificity of TSE-DWI-CT fusion imaging for cholesteatomas were 96.0% and 88.9%, respectively. Depending on whether the cholesteatoma extended to the mastoid, TSE-DWI-CT fusion imaging demonstrated good agreement with the intraoperative record for localization of lesions (κ = 0.808) and had a high accuracy of localization by the STAM system. Turbo spin-echo-DWI-CT fusion images have a very high diagnostic value for the preoperative localization of cholesteatomas.

Differences in apparent diffusion coefficients between normal brain echo-planar images and turbo spin-echo diffusion-weighted images with distortion correction

PurposeWe performed echo-planar imaging (EPI) and turbo spin-echo (TSE) diffusion-weighted imaging (DWI) using magnetic resonance imaging (MRI) to obtain basic clinical data of the apparent diffusion coefficient (ADC) in various parts of normal brains and compared the datasets using our retrospective distortion correction technique. Materials and methodsThe normal brains of 32 patients who underwent health check were scanned on a 1.5-T MRI instrument using EPI- and TSE-DWI. Distortion was corrected by (1) segmentation: the b0 images were segmented based on the plural threshold values; (2) edge detection: the edge was detected in the images obtained in step (1); (3) non-rigid image registration: non-rigid image registration using Demons algorithm was achieved between the b0 images of EPI-DWI and TSE-DWI, thereby, creating a displacement field; and (4) image warp: the displacement field was applied to the b1000 image to warp. Twenty-six parts of the brain were measured from the images of b0 and b1000 and the ADCs were calculated. The signal-to-noise ratio (SNR) of the cerebrospinal fluid was measured to identify the cause of the difference between the two sequences. These were compared using Wilcoxon signed-rank test (P = 0.05). ResultsThe ADC was significantly higher measured by EPI-DWI than by TSE-DWI. The SNR of EPI-DWI was significantly higher than that of the TSE-DWI. ConclusionCare must be taken when measuring ADCs near the base of the skull, such as the brain stem, where the SNR of the imaging technique is likely to decrease or distort.

A comparison among gamma distribution, intravoxel incoherent motion, and mono-exponential models with turbo spin-echo diffusion-weighted MR imaging in the differential diagnosis of orofacial lesions.

To compare the gamma distribution (GD), intravoxel incoherent motion (IVIM), and monoexponential (ME) models in terms of their goodness-of-fit, correlations among the parameters, and the effectiveness in the differential diagnosis of various orofacial lesions. A total of 85 patients underwent turbo spin-echo diffusion-weighted imaging with six b-values. The goodness-of-fit of three models was assessed using Akaike Information Criterion. We analysed the correlations and compared the effectiveness in the differential diagnosis among the parameters of GD model (κ, shape parameter; θ, scale parameter; fractions of diffusion: ƒ1, cellular component; ƒ2, extracellular diffusion; ƒ3, perfusion component), IVIM model (D, true diffusion coefficient; D*, pseudodiffusion coefficient; f, perfusion fraction), and ME model (apparent diffusion coefficient, ADC). The GD and IVIM models showed a better goodness-of-fit than the ME model (p < 0.05). ƒ1 had strong negative correlations with D and ADC (ρ = -0.901 and -0.937, respectively), while ƒ3 had a moderate positive correlation with f (ρ = 0.661). Malignant entity presented significantly higher ƒ1 and lower D and ADC than benign entity (p < 0.0001). Malignant lymphoma had significantly higher ƒ1 in comparison to squamous cell carcinoma (p = 0.0007) and granulation (p = 0.0075). The trend in ƒ1 was opposite to the trend in D. Malignant lymphoma had significant lower ƒ3 than squamous cell carcinoma (p = 0.005) or granulation (p = 0.0075). The strong correlations were found between the GD- and IVIM-derived parameters. Furthermore, the GD model's parameters were useful for characterising the pathological structure in orofacial lesions.

T-staging of rectal cancer: Utility of single-shot turbo spin-echo diffusion-weighted imaging with T2-weighted images and fusion images.

PurposeThe purpose of this study was to evaluate the usefulness of turbo spin-echo (TSE) DWI with fusion images in the T-staging compared with T2-weighted imaging (T2WI) alone and conventional echo-planner imaging (EPI) DWI.MethodsIn this prospective study, 4-mm-thick axial EPI-DWI, TSE-DWI, and T2WI were performed with the same slice locations for 20 patients with rectal cancer. Fusion images of DWI and T2WI were created for both EPI-DWI and TSE-DWI. Ten readers independently diagnosed the T-stages and scored the degree of confidence referring to T2WI alone and then to DWI, T2WI, and fusion images (DWI+T2WI) for each EPI-DWI and TSE-DWI. Visual score assessments of image quality were performed for each DWI.ResultsInter-observer agreement of T-staging for 10 readers was slight on T2WI alone but fair on EPI-DWI+T2WI and excellent on TSE-DWI+T2WI images. No readers gave higher confidence scores for T2WI compared to EPI/TSE-DWI+T2WI and for EPI-DWI+T2WI compared to TSE-DWI+T2WI. In seven pathologically-proven cases, poor, poor to slight, and fair to perfect agreements with the pathological T-stage were observed with T2WI alone, EPI-DWI+T2WI, and TSE-DWI+T2WI, respectively. All readers gave higher scores regarding image distortion and lower scores regarding image noise for TSE-DWI compared to EPI-DWI. For DWI utility, higher scores were assigned for TSE-DWI compared to EPI-DWI in 7 readers and there were no significant differences in the other 3 readers.ConclusionTSE-DWI images might be more appropriate for image fusion with T2WI and rectal cancer T-staging compared with EPI-DWI and T2WI alone.

Turbo Spin-echo Diffusion-weighted Imaging Compared with Single-shot Echo-planar Diffusion-weighted Imaging: Image Quality and Diagnostic Performance When Differentiating between Ductal Carcinoma in situ and Invasive Ductal Carcinoma.

Purpose:To compare the image quality between turbo spin-echo (TSE)-diffusion weighted imaging (DWI) and single-shot echo-planar imaging (EPI)-DWI, and to verify the diagnostic performance of the apparent diffusion coefficient (ADC) parameters of the two techniques by using histogram analysis in terms of differentiation between ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) lesions.Methods:Ninety-four women with 94 lesions diagnosed as breast cancer by surgery underwent IRB-approved preoperative magnetic resonance imaging, including TSE and EPI-DWI with b-values of 50 and 850 s/mm2. Twenty lesions were identified as DCIS and 74 as IDC. Image quality [signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and geometric distortion] was evaluated quantitatively and compared between the TSE and EPI-DWI. A histogram analysis of the entire tumor voxel-based ADC data was performed, and the 10th, 25th, 50th, 75th, and 90th percentile values of each technique were compared between DCIS and IDC lesions.Results:The SNR and CNR of TSE-DWI were significantly higher than those of EPI-DWI (P < 0.0001 and < 0.0001). The geometric distortion of TSE-DWI was significantly lower than that of EPI-DWI (P < 0.0001). In TSE-DWI, the 10th, 25th, 50th, and 75th percentile values were significantly different between the DCIS and IDC lesions (P = 0.0010, 0.0004, 0.0008, and 0.0044, respectively). In EPI-DWI, the 50th and 75th percentile values were significantly different between the two groups (P = 0.0009 and 0.0093). There was no significant difference in the area under the curve of the receiver operating characteristic analysis of the 10th, 25th, 50th, and 75th percentile values of TSE-DWI, and the 50th and 75th percentile values of EPI-DWI (P = 0.29).Conclusion:The image quality of TSE-DWI was better than that of EPI-DWI. DCIS lesions were distinguished from IDC lesions with a wider range of percentile values in TSE-DWI than in EPI-DWI, although diagnostic performance was not significantly different between the techniques.

The value of turbo spin-echo diffusion weighted imaging in the diagnosis of temporal bone cholesteatoma

Objective:The aim of this study is to evaluate the diagnostic value of turbo spin-echo（TSE） diffusion weighted imaging（DWI） in temporal bone cholesteatoma. Method:A prospective evaluated of 76 patients with suspected sacral cholesteatoma was performed using a Philips Ingenia 3.0T superconducting magnetic resonance scanner and a 32-channel head coil with turbo spin-echo diffusion weighted imaging（TSE-DWI） sequence and conventional magnetic resonance scan, and underwent surgery within the next two weeks. The pathological result is the gold standard, and the imaging diagnosis and surgery are performed. The intraoperative observation and pathological results were compared. The diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value of TSE-DWI sequence in the diagnosis of temporal bone cholesteatoma were calculated. Result:Of the 76 patients with suspected temporal bone cholesteatoma, TSE-DWI scan was performed, 44 cases were diagnosed as cholesteatoma and 32 cases were non-cholesteatoma. Based on the pathology results, 46 cases were diagnosed as cholesteatoma, 30 cases were non-cholesteatoma. The accuracy of TSW-DWI sequence in the diagnosis of cholesteatoma was 89.47%, 3 cases were false negative and 5 cases was false positive. The sensitivity, specificity, positive predictive value and negative predictive value of TSE-DWI in the diagnosis of temporal bone cholesteatoma were 89.13%, 90.00%, 93.18%, and 84.38%, respectively. Conclusion:The TSE-DWI sequence has high signal-to-noise ratio and can improve the diagnostic accuracy and specificity. TSE-DWI sequence is of great value in clinical diagnosis and treatment.

The value of turbo spin-echo diffusion-weighted imaging apparent diffusion coefficient in the diagnosis of temporal bone cholesteatoma

To explore the value of the applying the apparent diffusion coefficient (ADC) to the quantitative diagnosis of temporal bone cholesteatoma. Seventy-one patients clinically suspected of temporal bone cholesteatoma were enrolled prospectively. These patients underwent ear magnetic resonance imaging (MRI) and turbo spin-echo diffusion-weighted imaging (TSE-DWI) using a Philips Ingenia 3 T superconductive MRI system, and their ADCs were measured. Subsequently, all enrolled patients underwent surgery within 15 days of the MRI. Using receiver operating characteristic (ROC) curve analysis, the optimal threshold and diagnostic performance for diagnosing temporal bone cholesteatoma were determined. Logistic regression modelling was used to combine ADCs and T1-weighted imaging (T1WI) sequences and calculate the combined diagnostic performance. Based on the pathology results, patients were categorised into the cholesteatoma group (CS group, n=43) and the non-cholesteatoma group (NCS group, n=28). In the CS group, ADCs were significantly lower (mean, 0.87±0.31×10-3 mm2/s) than in the NCS group (mean, 1.87±0.49×10-3 mm2/s; p<0.001); the area under the ROC curve (AUC) was 0.915. Based on the optimal threshold of ADC, ≤1.23×10-3 mm2/s, the diagnostic performance was high; the sensitivity and specificity for diagnosing cholesteatoma were 95.35% and 85.71%, respectively. By combining the ADC and T1WI sequence, AUC increased to 0.953, and the sensitivity and specificity were 90.7% and 96.43%, respectively. ADC quantitative analysis has a high value in the preoperative diagnosis of cholesteatoma, and the combination of ADC and T1WI sequences can improve the diagnostic accuracy and specificity and thereby facilitate clinically effective diagnosis.

Evaluation of pituitary structures and lesions with turbo spin-echo diffusion-weighted imaging

Background and purposeTurbo spin-echo diffusion-weighted imaging (TSE-DWI) has not been used for evaluating pituitary lesions. We compared the usefulness of TSE-DWI and echo-planar (EP)-DWI for assessing normal pituitary structures and lesions. Materials and methodsOur study included 41 consecutive patients (27 pituitary adenomas, 8 Rathke's cleft cysts, 4 craniopharyngiomas, 1 germinoma, 1 pituitary metastasis) who underwent conventional pre- and post-contrast magnetic resonance imaging (MRI) and TSE- and EP-DWI at 3T. Two observers independently performed qualitative assessment of normal pituitary structures and lesions on sagittal DWI and apparent diffusion coefficient (ADC) maps. One observer recorded ADC values of normal brain structures and pituitary lesions. Kappa (κ) statistics, Wilcoxon signed-rank test, intraclass correlation coefficient, Bland-Altman analysis, Pearson correlation coefficient and independent t-test were used for statistical analysis. ResultsInterobserver agreement for qualitative evaluations was good to excellent (κ = 0.65–1.0). On both DWI and ADC maps, visualization of the pituitary gland, of the spatial relationship between the lesion and its normal surroundings, and the whole image quality were significantly better on TSE- than EP sequences (p < .01). In normal brain structures, the ADC value on TSE- and EP-sequences was significantly correlated (r = 0.6979, p < .05). The TSE-ADC value was significantly lower for pituitary adenomas than craniopharyngiomas (p < .05). ConclusionsFor the evaluation of normal pituitary structures and lesions, TSE-DWI is more useful than EP-DWI. The TSE-ADC value may help to differentiate between pituitary adenoma and craniopharyngioma.

Analysis of Magnetic Resonance Signals from Diffusion Weighted Imaging using Compressed Sensitivity Encoding Technique

The purpose of this study was to compare image quality between compressed sensitivity encoding (CS) and sensitivity encoding (SENSE) in single-shot turbo spin echo diffusion-weighted imaging (TSE-DWI). Signal-tonoise ratios (SNR), apparent diffusion coefficient (ADC) values, and geometric accuracies were measured with an American College of Radiology head phantom. CS showed a high mean SNR, less variation in ADC values, and reduced imaging acquisition time (21.7 %-39.3 %) compared with SENSE. In addition, there was no significant difference in geometric accuracy between SENSE and CS. In conclusion, in comparison with SENSE TSE-DWI, CS TSE-DWI resulted in a reduced imaging acquisition time and improved SNR, while maintaining image quality.

Accuracy of turbo spin-echo diffusion-weighted imaging signal intensity measurements for the diagnosis of cholesteatoma.

We aimed to evaluate the diagnostic accuracy of turbo spin-echo diffusion-weighted imaging (TSE-DWI) at 3 T, for cholesteatoma (CS) diagnosis, using qualitative and quantitative methods with numerical assessment of signal intensity (SI), signal intensity ratios (SIR), and apparent diffusion coefficient (ADC) values. In this retrospective study, two blinded observers independently evaluated the preoperative TSE-DWI images of 57 patients who were imaged with a presumed diagnosis of CS. Qualitative assessment with respect to the SI of the adjacent cortex and quantitative measurements of SI, SIR, and ADC values were performed. Surgery with histopathologic examination revealed 30 CS patients and 27 patients with non-cholesteatoma (NCS) lesions including chronic inflammation and cholesterol granuloma. On TSE-DWI, 96.7% of the CS lesions and none of the NCS lesions appeared hyperintense compared with the cortex. The mean SI and SIR indices of the CS group were significantly higher and the mean ADC values significantly lower compared with those of the NCS group (P < 0.001). Using specific cutoff values for SI (92.5) and SIR (0.9), CS could be diagnosed with 100% sensitivity and specificity. The use of quantitative imaging further increased the sensitivity of the TSE-DWI technique. The quantitative indices of SI, SIR, and ADC of TSE-DWI appear to be highly accurate parameters that can be used to confirm the diagnosis of CS.

Multishot cartesian turbo spin-echo diffusion imaging using iterative POCSMUSE Reconstruction.

To report a diffusion imaging technique insensitive to off-resonance artifacts and motion-induced ghost artifacts using multishot Cartesian turbo spin-echo (TSE) acquisition and iterative POCS-based reconstruction of multiplexed sensitivity encoded magnetic resonance imaging (MRI) (POCSMUSE) for phase correction. Phase insensitive diffusion preparation was used to deal with the violation of the Carr-Purcell-Meiboom-Gill (CPMG) conditions of TSE diffusion-weighted imaging (DWI), followed by a multishot Cartesian TSE readout for data acquisition. An iterative diffusion phase correction method, iterative POCSMUSE, was developed and implemented to eliminate the ghost artifacts in multishot TSE DWI. The in vivo human brain diffusion images (from one healthy volunteer and 10 patients) using multishot Cartesian TSE were acquired at 3T and reconstructed using iterative POCSMUSE, and compared with single-shot and multishot echo-planar imaging (EPI) results. These images were evaluated by two radiologists using visual scores (considering both image quality and distortion levels) from 1 to 5. The proposed iterative POCSMUSE reconstruction was able to correct the ghost artifacts in multishot DWI. The ghost-to-signal ratio of TSE DWI using iterative POCSMUSE (0.0174 ± 0.0024) was significantly (P < 0.0005) smaller than using POCSMUSE (0.0253 ± 0.0040). The image scores of multishot TSE DWI were significantly higher than single-shot (P = 0.004 and 0.006 from two reviewers) and multishot (P = 0.008 and 0.004 from two reviewers) EPI-based methods. The proposed multishot Cartesian TSE DWI using iterative POCSMUSE reconstruction can provide high-quality diffusion images insensitive to motion-induced ghost artifacts and off-resonance related artifacts such as chemical shifts and susceptibility-induced image distortions. 1 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:167-174.

Comparison of accuracy of intravoxel incoherent motion and apparent diffusion coefficient techniques for predicting malignancy of head and neck tumors using half-Fourier single-shot turbo spin-echo diffusion-weighted imaging

PurposeTo evaluate the use of the intravoxel incoherent motion (IVIM) technique in half-Fourier single-shot turbo spin-echo (HASTE) diffusion-weighted imaging (DWI), and to compare its accuracy to that of apparent diffusion coefficient (ADC) to predict malignancy in head and neck tumors. Patients and methodsHASTE DW images of 33 patients with head and neck tumors (10 benign and 23 malignant) were evaluated. Using the IVIM technique, parameters (D, true diffusion coefficient; f, perfusion fraction; D*, pseudodiffusion coefficient) were calculated for each tumor. ADC values were measured over a range of b values from 0 to 1000s/mm2. IVIM parameters and ADC values in benign and malignant tumors were compared using Student's t test, receiver operating characteristics (ROC) analysis, and multivariate logistic regression modeling. ResultsMean ADC and D values of malignant tumors were significantly lower than those of benign tumors (P<0.05). Mean D* values of malignant tumors were significantly higher than those of benign tumors (P<0.05). There was no significant difference in mean f values between malignant and benign tumors (P>0.05). The technique of combining D and D* was the best for predicting malignancy; accuracy for this model was higher than that for ADC. ConclusionsThe IVIM technique may be applied in HASTE DWI as a diagnostic tool to predict malignancy in head and neck masses. The use of D and D* in combination increases the diagnostic accuracy in comparison with ADC.

Diffusion-weighted imaging of skull lesions.

Diffusion-weighted imaging can increase the conspicuity of skull lesions and be applied toward noninvasive differentiation of malignant from benign lesions. Malignant skull lesions generally display lower diffusivity than benign lesions, although there are exceptions, and clinical parameters and conventional imaging modalities should also be considered in the evaluation of skull lesions. Nevertheless, in some instances diffusion-weighted imaging (DWI) can be used for problem solving when conventional imaging features are indeterminate, such as with skull base involvement by nasopharyngeal carcinoma versus osteomyelitis. In addition, DWI may be useful for monitoring treatment effects. The use of readout segmented technique, parallel imaging, multishot acquisition, turbo spin-echo DWI, diffusion tensor imaging, and higher field strengths can improve image quality. The feasibility of implementing DWI for characterizing skull lesions, the DWI findings of benign and malignant skull lesions, and technical considerations are discussed in this article.

The value of single-shot turbo spin-echo diffusion-weighted MR imaging in the detection of middle ear cholesteatoma

Single-shot (SS) turbo spin-echo (TSE) diffusion-weighted (DW) magnetic resonance imaging (MRI) is a non echo-planar imaging (EPI) technique recently reported for the evaluation of middle ear cholesteatoma. We prospectively evaluated a SS TSE DW sequence in detecting congenital or acquired middle ear cholesteatoma and evaluated the size of middle ear cholesteatoma detectable with this sequence. The aim of this study was not to differentiate between inflammatory tissue and cholesteatoma using SS TSE DW imaging. A group of 21 patients strongly suspected clinically and/or otoscopically of having a middle ear cholesteatoma without any history of prior surgery were evaluated with late post-gadolinium MRI including this SS TSE DW sequence. A total of 21 middle ear cholesteatomas (5 congenital and 16 acquired) were found at surgery with a size varying between 2 and 19 mm. Hyperintense signal on SS TSE DW imaging compatible with cholesteatoma was found in 19 patients. One patient showed no hyperintensity due to autoevacuation of the cholesteatoma sac into the external auditory canal. Another patient showed no hyperintensity because of motion artifacts. This study shows the high sensitivity of this SS TSE DW sequence in detecting small middle ear cholesteatomas, with a size limit as small as 2 mm.