Spectral Adiabatic Inversion Recovery Research Articles

Beyond mean value analysis - a voxel-based analysis of the quantitative MR biomarker water T2 in the presence of fatty infiltration in skeletal muscle tissue of patients with neuromuscular diseases.

The main pathologies in the muscles of patients with neuromuscular diseases (NMD) are fatty infiltration and edema. Recently, quantitative magnetic resonance (MR) imaging for determination of the MR biomarkers proton density fat fraction (PDFF) and water T2 (T2w ) has been advanced. Biophysical effects or pathology can have different effects on MR biomarkers. Thus, for heterogeneously affected muscles, the routinely performed mean or median value analyses of MR biomarkers are questionable. Our work presents a voxel-based histogram analysis of PDFF and T2w images to point out potential quantification errors. In 12 patients with NMD, chemical-shift encoding-based water-fat imaging for PDFF and T2 mapping with spectral adiabatic inversion recovery (SPAIR) for T2w determination was performed. Segmentation of nine thigh muscles was performed bilaterally (n = 216). PDFF and T2 maps were coregistered. A voxel-based comparison of PDFF and T2w showed a decreased T2w with increasing PDFF. Mean T2w and mean T2w without fatty voxels (PDFF < 10%) show good agreement, whereas standard deviation (σ) T2w and σ T2w without fatty voxels show increasing difference with increasing values of σ. Thereby two subgroups can be observed, referring to muscles in which the exclusion of fatty voxels has a negligible influence versus muscles in which a strong dependency of the T2w value distribution on the exclusion of fatty voxels is present. Because of the two opposite effects that influence T2w in a voxel, namely, (i) a pathophysiologically increased water mobility leading to T2w elevation, and (ii) a dependency of T2w on the PDFF leading to decreased T2w , the T2w distribution within a muscle might be heterogenous andthe routine mean or median analysis can lead to a misinterpretation of the muscle health. It was concluded that muscle T2w mean values can wrongly suggest healthy muscle tissue. A deeper analysis of the underlying value distribution is necessary. Therefore, a quantitative analysis of T2w histograms is a potential alternative.

Single-shot RARE with Dixon: Application to robust abdominal imaging with uniform fat and water separation at 3T.

To develop a true single shot turbo spin echo (SShTSE) acquisition with Dixon for robust T2 -weighted abdominal imaging with uniform fat and water separation at 3T. The in-phase (IP) and out-of-phase (OP) echoes for Dixon processing were acquired in the same repetition time of a SShTSE using partial echoes. A phase-preserved bi-directional homodyne reconstruction was developed to compensate the partial echo and the partial phase encoding of SShTSE. With IRB approval, the SShTSE-Dixon was compared against standard SShTSE, without and with fat suppression using spectral adiabatic inversion recovery (SPAIR) in 5 healthy volunteers and 5 patients. The SNR and contrast ratio (CR) of spleen to liver were compared among different acquisitions. The bi-directional homodyne reconstruction successfully minimized ringing artifacts because of partial acquisitions. SShTSE-Dixon achieved uniform fat suppression compared to SShTSE-SPAIR with fat suppression failures of 1/10 versus 10/10 in the axial plane and 0/5 versus 5/5 in the coronal plane, respectively. The SNRs of the liver (12.2 ± 4.9 vs. 11.7 ± 5.2; P = .76) and spleen (25.9 ± 11.6 vs. 23.7 ± 9.7; P = .14) were equivalent between fat-suppressed images (SShTSE-Dixon water-only and SShTSE-SPAIR). The SNRs of liver (14.4 ± 5.7 vs. 13.4 ± 5.0; P = .60) and spleen (26.5 ± 10.1 vs. 25.7 ± 8.5; P = .56) were equivalent between non-fat-suppressed images (SShTSE-Dixon IP and SShTSE). The CRs of spleen to liver were also similar between fat-suppressed images (2.6 ± 0.4 vs. 2.5 ± 0.5; P =.92) and non-fat-suppressed images (2.3 ± 0.6 vs. 2.2 ± 0.4; P =.84). SShTSE-Dixon generates robust abdominal T2 -weighted images at 3T with and without uniform fat suppression, along with perfectly co-registered fat-only images in a single acquisition.

Quantitative T2 mapping of rats with chronic hepatitis

The aim of the study was to explore the diagnostic value of T2 mapping in an experimental rat model of chronic liver disease. Chronic hepatitis was induced in Sprague-Dawley male rats (n=88) by intraperitoneal and abdominal subcutaneous injection of carbon tetrachloride in olive oil. The normal control rats (n=12) were similarly injected with the same dose of normal saline. All rats were randomly selected and subjected to T2-weighted/spectral adiabatic inversion recovery and multiple gradient- and spin-echo sequence. After scanning, rats were sacrificed immediately and livers removed for staining with hematoxylin and eosin, as well as Masson's trichrome, to determine the pathological stage of hepatic fibrosis, necroinflammatory activity and steatosis. The T2 values were measured and associated with histopathological findings. The T2 values were significantly associated with hepatic fibrosis (P<0.05), but not with hepatitis (P>0.05) or steatosis (P>0.05). By partial correlation analysis, a significant positive correlation was observed between the T2 values and stages of liver fibrosis (r=0.820; P<0.05). T2 values increased with progressive hepatic fibrosis. The differences between T2 values and stages of liver fibrosis were statistically significant. Statistically significant differences were observed between different stages of liver fibrosis (P<0.05), with an area under the curve value of 0.944 for predicting stage F1 or greater, 0.942 for stage F2 or greater, 0.958 for stage F3 or greater, and 0.948 for F4. Thus, the T2 value is one of the quantitative indices of imaging and accurately reflects the stages of liver fibrosis.

Prediction of the Incomplete Region of Fat Suppression Using the Banding Artifact of the Balanced Steady-state Free Precession Sequence

When the fat-suppression technique was used in the MRI examinations of neck and extremities, incomplete regions of fat suppression were depicted frequently. These incomplete regions were caused by the non-uniform static magnetic field (B0). On the other hand, a non-uniform B0 caused banding artifacts using a balanced steady-state free precession (bSSFP) sequence. We investigated the prediction of incomplete regions of fat suppression using the banding artifacts of the bSSFP sequence. The fat-suppression techniques used in this study were the chemical shift selective and spectral adiabatic inversion recovery methods for turbo spin echo imaging. Using an oil bottle attached to a staple, the scan parameters of the bSSFP sequence were adjusted to overlap with the banding artifacts in the incomplete regions of fat suppression. The neck, ankle joint and femur of healthy volunteers were scanned using the obtained scan parameters, and a visual assessment was performed. As a result, the incomplete region of fat suppression matched the region of the banding artifact. We were able to predict the incomplete region of fat suppression using the banding artifacts of the bSSFP sequence. If the optimized bSSFP sequence is used as the localizer, we can assess the situation of incomplete fat suppression before the main scanning and reduce rescanning due to incomplete fat suppression.

PERBEDAAN SIGNAL TO NOISE RATIO (SNR) ANTARA SEKUENS PDW_SPAIR (SPECTRAL ADIABATIC INVERSION RECOVERY) DENGAN SEKUENS PDW_FATSAT(FAT SATURATION) PADA PEMERIKSAAN MRI KNEE JOINT POTONGAN SAGITAL

Background : In some cases, an MRI exam have difficulty distinguishing fat and soft tissue around. Fat is often a source of problems in MRI, because fat around many anatomical structures, but not well constrained. Spair and Fatsat is a technique used to suppress the fat signal. Signal To Noise Ratio (SNR) is an influential factor in a lot of quality MRI image. This study aims to determine the difference in value SNR between sequences PDW_SPAIR and PDW_Fatsat MRI Knee Joint Pieces Sagittal.&#x0D; Method : This research is a quantitative study with an experimental approach. Data were collected from November to December 2016 at the Radiology Siloam Hospital Lippo Village. Data taken from the examination using MRI Knee Joint PDW_SPAIR sequences and PDW_Fatsat on 10 probandus. Data was analyzed using software measurement ROI (Region Of Interest) in the organs of articular cartilage, anterior cruciate ligament, posterior cruciate ligament and Meniscus. then calculated the value of SNR, SNR values ​​are tested with Shapiro Wilk normality test and showed normal distribution of data is then performed statistical tests using paired T test to determine whether or not there is a difference of the two sequences.&#x0D; Result : Research show that there are differences between the sequences PDW_SPAIR SNR with PDW_Fatsat MRI Knee joint with a p value of 0.000 (p &lt;0.05). When viewed from the mean value of the sequence PDW_SPAIR MRI Knee joint sagittal slice generate value SNR better than PDW_Fatsat sequences with a mean of 42.10 PDW_SPAIR and a mean value of 35.14 PDW_Fatsat.&#x0D; Conclusion: There is a difference Signal to Noise Ratio (SNR) between PDW_SPAIR (Spectral Adiabatic Inversion Recovery) sequence with PDW_Fatsat (Fat Saturation) sequence in examination of MRI Knee Joint Sagital Pieces with a significance level of p-value 0,000 (p&lt;0,05). PDW_SPAIR sequence is an optimal value for Signal to Noise Ratio (SNR)in examination of MRI Knee Joint sagital pieces

Water T2 Mapping in Fatty Infiltrated Thigh Muscles of Patients With Neuromuscular Diseases Using a T2 -Prepared 3D Turbo Spin Echo With SPAIR.

Muscle water T2 (T2w ) has been proposed as a biomarker to monitor disease activity and therapy effectiveness in patients with neuromuscular diseases (NMD). Multi-echo spin-echo (MESE) is known to be affected by fatty infiltration. A T2 -prepared 3D turbo spin echo (TSE) is an alternative method for T2 mapping, but has been only applied in healthy muscles. To examine the performance of T2 -prepared 3D TSE in combination with spectral adiabatic inversion recovery (SPAIR) in measuring T2w in fatty infiltrated muscles based on simulations and in vivo measurements in thigh muscles of patients with NMD. Prospective. One healthy volunteer, 34 NMD patients. T2 -prepared stimulated echo acquisition mode (STEAM) magnetic resonance spectroscopy (MRS), SPAIR STEAM MRS, and SPAIR T2 -prepared STEAM MRS were performed in the subcutaneous fat of a healthy volunteer's thigh. T2 mapping based on SPAIR 2D MESE and SPAIR T2 -prepared 3D TSE was performed in the NMD patients' thigh region. Multi-TE STEAM MRS was performed for measuring a reference T2w at different thigh locations. The behavior of the fat spectrum in the SPAIR T2 -prepared 3D TSE was simulated using Bloch simulations. The in vivo T2 results of the imaging methods were compared to the in vivo T2w MRS results. Pearson correlation coefficient with slope and intercept, relative error. The simulated T2 for the SPAIR T2 -prepared 3D TSE sequence remained constant within a relative error of not more than 4% up to a fat fraction of 80%. In vivo T2 values of SPAIR T2 -prepared 3D TSE were in good agreement with the T2w values of STEAM MRS (R = 0.86; slope = 1.12; intercept = -1.41 ms). In vivo T2 values of SPAIR 2D MESE showed large deviations from the T2w values of STEAM MRS (R = 0.14; slope = 0.32; intercept = 38.83 ms). The proposed SPAIR T2 -prepared 3D TSE shows reduced sensitivity to fatty infiltration for T2w mapping in the thigh muscles of NMD patients. 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:1727-1736.

Performing clinical 18F-FDG-PET/MRI of the mediastinum optimising a dedicated, patient-friendly protocol.

To construct a mediastinal-specific fluorine-18-fluorodeoxyglucose (F-FDG)-PET/MR protocol with high-quality MRI of minimal acquisition-time and comparable diagnostic value to F-FDG-PET/computed tomography (CT). Fifteen healthy participants received PET/MRI and 10 patients with mediastinal tumours (eight non-small-cell lung, two oesophageal cancer) received F-FDG-PET/MRI immediately after F-FDG-PET/CT. Sequences volume interpolated breath-hold examination (T1-VIBE) and Half-Fourier acquisition single-shot turbo spin echo (T2-HASTE) were optimised by varying the parameters: breath-hold (BH, end-expiration), fat suppression (spectral adiabatic inversion recovery), and ECG-triggering (ECG, end-diastole). Image quality (IQ) of each sequence-variation was qualitatively scored by medical experts and quantitatively assessed by calculating signal-to-noise ratios, contrast relative to muscle, standardized-uptake-value, and tumour-to-blood ratios. Patient comfort was evaluated on patients' experience. Diagnostic accuracy of F-FDG-PET/MRI was compared to F-FDG-PET/CT, in reference to histopathology/cytopathology. ECG-triggered T1-VIBE images showed the highest signal-to-noise ratio (P < 0.01) and the largest contrast between mediastinal soft-tissues, regardless of BH or free-breathing acquisition. IQ of ECG-triggered T1-VIBE scans in BH were scored qualitatively highest with good reader agreement (κ = 0.62). IQ of T2-HASTE was not significantly affected by BH acquisition (P > 0.9). Qualitative IQ of T1-VIBE and T2-HASTE declined after spectral adiabatic inversion recovery fat-suppression. All patients could maintain BH at end-expiration and reported no discomfort. Diagnostic performance of F-FDG-PET/MR was not significantly different from F-FDG-PET/CT with comparable staging, standardized-uptake-values, and tumour-to-blood ratios. However, T-status was more often over-staged on F-FDG-PET/CT, while N-status was more frequently under-staged on F-FDG-PET/MR. ECG-triggered T1-VIBE sequences acquired during short, multiple BHs are recommended for mediastinal imaging using F-FDG-PET/MR. With dedicated protocols, F-FDG-PET/MRI will be useful in thoracic oncology and aid in diagnostic evaluation and tailored treatment decision-making.

PERBEDAAN INFORMASI CITRA ANATOMI MRI PELVIS SEKUENS T1 WEIGHTED POTONGAN SAGITAL PADA KASUS KANKER SERVIKS DENGAN VARIASI SUPRESSION LEVEL SPECTRAL ADIABATIC INVERSION RECOVERY (SPAIR)

Background : MRI Pelvic examination with cervical cancer case using the fat suppression SPAIR method to suppress fat to get an optimal picture. In SPAIR, there are three variations of fat suppression namely Strong Supression Level, SPAIR Supression Level Medium and SPAIR Supression Level Weak. At the Radiology Installation at Saiful Anwar Malang Hospital, the pelvic MRI examination used a weak SPAIR sequence while Dr. Sardjito uses strong SPAIR. This study aims to determine differences in information on pelvic MRI anatomical images and to find out better information on anatomical images on MRI pelvis T1 weighted sagittal sequences in cervical cancer cases with variations in Supression Level Spectral Adiabatic Inversion Recovery (SPAIR)&#x0D; Methods : The research used quantitative research method with experimental approach where is done in Radiology Installation of Dr. Sardjito Hospital Yogyakarta. The date were collected by examining MRI Pelvic with cervical cancer cases in 6 patients. Then scanning isdone on the sagittal piece with SPAIR Strong T1 Sequence, SPAIR Mediumand SPAIR Weak. Presented to three radiologist doctors of assess. Once the image judged by the three respondents, the the assessment results are summarized and then in a statistical test using SPSS version 16.0 with the method of friedman.&#x0D; Results : The result showed that there were significant diference of anatomical information between the SPAIR Strong, SPAIR Medium and SPAIR Weak on the MRI pelvic exmination of the sagittal cut in case of cervical cancer with p-value 0.003 (p&lt;0.005). the SPAIR Weak variation has better anatomical information in MRI Pelvic examination of the sagittal cut in case of cervical cancer with Mean Rank value of SPAIR Weak variation 3.00, followed by SPAIR Strong sequence with value 1.92 and low SPAIR Medium sequence with value 1.08.&#x0D; Conclusion : Significant values ​​were obtained with p value = 0.003 (p &lt;0.05) which means that there is information on anatomical information on MRI pelvis T1 weighted sagittal sequences in cervical cancer cases with the Spectral Adiabatic Inversion Recovery (SPAIR) Level suppression. Information on better anatomical images on MRI pelvis T1 weighted sagittal sequences in cervical cancer cases with the most optimal variation of Adiabatic Inversion Revovery (SPAIR) Suppression, namely weak SPAIR with mean rank of 3.00.&#x0D; &#x0D; Keywords : SPAIR, Cervices Cancer, MRI Pelvi

Clinical Magnetic Resonance Imaging of the Knee at 7 T: Optimization of Fat Suppression.

The aim of this study was to evaluate the efficiency and performance of different fat suppression techniques for clinical 7 T knee magnetic resonance imaging including the slice-selective gradient reversal (SSGR) technique. This article is an ethical board-approved prospective study with written informed consent from 8 volunteers (mean, 31 ± 4 years). It included fat phantom and knee magnetic resonance imaging at 3 T (Magnetom Skyra; Siemens Healthcare) and at 7 T (Achieva, Philips Healthcare). At 3 T, an axial proton density-weighted turbo spin echo sequence with spectral adiabatic inversion recovery (SPAIR) was acquired. At 7 T, a series of 5 proton density-weighted turbo spin echo sequences was acquired: (a) without fat suppression, (b) with spectral presaturation with inversion recovery (SPIR), (c) with SPAIR, (d) with SSGR, and (e) with the combination of SSGR + SPIR. Additional noise scans allowed pixelwise calculation of signal-to-noise ratio and contrast-to-noise ratio maps. Quantitative data at 7 T were compared with each other but not to 3 T. Two independent radiologists evaluated overall image quality, homogeneity and grade of fat suppression, and the delineation between 2 adjacent structures. Results were compared using Wilcoxon signed rank and paired sample t tests. Relative signal-to-noise ratios of fat demonstrated that the SPIR technique reduced the fat signal to 45% ± 5.4%; SPAIR, 18% ± 1.2%; SSGR, 14% ± 1.1%; and SSGR + SPIR, 11% ± 0.3%. Contrast-to-noise ratio showed superior contrast between muscle-fat (P < 0.001) and fluid-fat (P ≤ 0.001) for SSGR and SSGR + SPIR. The radiologists rated the overall image quality higher at 7 T than 3 T. The homogeneity and grade of fat suppression as well as the delineation between 2 different (adjacent) structures were rated best for SSGR + SPIR. At 7 T, fat saturation for clinical knee imaging using SSGR and the combination of SSGR + SPIR was superior compared with standard methods based on spectrally selective radiofrequency pulses.

Diagnostic Value of Magnetic Resonance Neurography in Cervical Radiculopathy: Plexus Patterns and Peripheral Nerve Lesions.

The aim of this study was to assess the imaging appearance and diagnostic value of plexus and peripheral nerve magnetic resonance neurography (MRN) in cervical radiculopathy. This prospective study was approved by our institutional ethics committee and written informed consent was obtained from all participants. A total of 24 patients were included with a diagnosis of cervical radiculopathy based on clinical examination, supporting electrophysiological examinations and spinal imaging consistent with the clinical syndrome. All patients then underwent a high-resolution MRN protocol including the brachial plexus from nerve roots to plexus cords using a 3-dimensional turbo spin echo with variable flip angle short tau inversion recovery and sagittal-oblique T2-weighted spectral adiabatic inversion recovery sequence, and ulnar, median, and radial nerves at the upper arm and elbow in T2-weighted fat saturated sequences. Two readers independently rated plexus elements regarding the presence of lesions at neuroforaminal levels, roots, trunks, and cord segments. Median, ulnar, and radial nerves were likewise rated. Findings were then compared to a referenced standard of cervical radiculopathy that was defined as the combined diagnosis of clinical syndrome including supporting electrophysiological exams and matching positive spinal imaging, and diagnostic performance parameters were calculated. Additional quantitative and qualitative analysis assessed peripheral nerve caliber and normalized T2-signal at arm level in cervical radiculopathy and compared them to 25 inflammatory neuropathy controls. Cervical radiculopathy resulted in distinct plexus lesion patterns for each level of neuroforaminal stenosis. Overall, brachial plexus MRN in cervical radiculopathy reached a sensitivity of 81%, a specificity of 96%, a positive predictive value of 87%, and overall diagnostic accuracy of 87%. Initial spinal magnetic resonance imaging showed multiple positive findings for clinically unaffected root levels and resulted in a specificity of 69%, a positive predictive value of 54%, and an overall diagnostic accuracy of 78%.T2-weighted peripheral nerve lesions were detected in 79% of cervical radiculopathy cases and imitated imaging appearance of inflammatory neuropathies both quantitatively and qualitatively. Complementing spine imaging in cervical radiculopathy with brachial plexus MRN can improve diagnostic accuracy by increasing specificity and positive predictive value. T2-weighted lesions of peripheral nerves can be caused by cervical radiculopathy, which must be considered a relevant diagnostic pitfall in MRN of peripheral neuropathies.

The Influence of Fat Suppression Technique on Diffusion-weighted (DW) MRI in Lung Cancer

Purpose: To qualitatively and quantitatively investigate the effect of common vendor-related sequence variations in fat suppression techniques on the diagnostic performance of free-breathing DW protocols for lung imaging.Methods: 8 patients with malignant lung lesions were scanned in free breathing using two diffusion-weighted (DW) protocols with different fat suppression techniques: DWA used short-tau inversion recovery (STIR), and DWB used Spectral Adiabatic Inversion Recovery (SPAIR). Both techniques were obtained at two time points, between 1 hour and 1 week apart. Image quality was assessed using a 5-point scoring system. The number of lesions visible within lung, mediastinum and at thoracic inlet on the DW (b=800 s/mm2) images was compared. Signal-to-noise ratios (SNR) were calculated for lesions and para-spinal muscle. Repeatability of ADC values of the lesions was estimated for both protocols together and separately.Results: There was a signal void at the thoracic inlet in all patients with DWB but not with DWA. DWA images were rated significantly better than DWB images overall quality domains. (Cohen’s κ = 1). Although 8 more upper mediastinal/thoracic inlet lymph nodes were detected with DWA than DWB, this did not reach statistical significance (p = 0.23). Tumour ADC values were not significantly different between protocols (p=0.93), their ADC reproducibility was satisfactory (CoV=7.7%) and repeatability of each protocol separately was comparable (CoVDWA=3.7% (95% CI 2.5 – 7.1%) and CoVDWB=4.6% (95% CI 3.1 – 8.8%)).Conclusion: In a free-breathing DW-MRI protocol for lung, STIR fat suppression produced images of better diagnostic quality than SPAIR, while maintaining comparable SNR and providing repeatable quantitative ADC acceptable for use in a multicentre trial setting.

Correlation between glycolytic activity on [18F]-FDG-PET and cell density on diffusion-weighted MRI in lymphoma at staging.

[18F]-FDG-PET/MR carries a high diagnostic value in whole-body oncologic imaging and allows simultaneous quantitative measurements of glucose metabolism (SUV) and cell density (ADC). To determine the relationship between SUV and ADC values extracted from simultaneously acquired [18F]-FDG-PET/MR data of patients with FDG-avid lymphomas at staging. Prospective. Patients with histologically proven lymphoma referred for staging. Hybrid PET/MR device (3T); axial, two-point Dixon, 3D, volume-interpolated, T1 -weighted breath-hold sequence; coronal T2 -weighted half-Fourier acquisition single-shot turbo spin-echo. Single-shot, echo-planar imaging-based, spectral adiabatic inversion recovery diffusion-weighted imaging. Staging was performed according to the modified Ann Arbor system by a board-certified radiologist and a board-certified nuclear medicine physician, blinded to the clinical and histological information, in consensus. SUVs and ADCs values were collected, for each positive nodal and extranodal region, from the lesion demonstrating the largest diameter. Descriptive data included absolute frequencies and percentages for categorical data, and arithmetic means and 95% confidence intervals for scale-type data. The Pearson correlation coefficient was used to assess the relationship between SUVs and ADCs (P ≤ 0.05). Additional separate analyses were performed according to histological lymphoma subtype, for nodal and extranodal lesions and excluding bone lesions. Overall, 100 patients were examined (55 males, 45 females; age ± SD in years, 51.6 ± 19.5). Histology revealed Hodgkin-lymphoma and non-Hodgkin-lymphoma in 26 and 74 patients, respectively. Twenty patients were stage I, 21 stage II, 24 stage III, and 31 stage IV on [18F]-FDG-PET/MR (ie, four patients negative at imaging). Based on 391 lesions (ie, 367 excluding bone lesions) no significant correlations between SUVmax and ADCmin, or between SUVmean and ADCmean, emerged (respectively, r = 0.091, P = 0.073, 95% CI [-0.01, 0.19] and r = -0.032, P = 0.527, 95% CI [-0.13, 0.07] including bone lesions; r = 0.06, P = 0.21, 95% CI [-0.04, 0.17] and r = -0.05, P = 0.32, 95% CI [-0.15, 0.05] excluding bone lesions). A significant correlation was observed only between ADCmean and SUVmean for follicular lymphoma (r = -0.33, P = 0.001). SUVs and ADCs were demonstrated to be independent biomarkers in lymphomas. A moderate correlation between SUVs and ADCs likely is present in follicular lymphoma. 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1217-1226.

Fat suppressed proton density MRI increases the sensitivity in the detection of cervical cord multiple sclerosis lesions

Introduction MR imaging is widely used method to aid in the detection of multiple sclerosis (MS) lesions in the cord. Improving the sensitivity of the detection of MS lesions can be useful in the medical diagnosis and could lead to a better approach and heal of the disease. Purpose The aim of this study was to compare T2-weighted turbo spin-echo (TSE) combined with spectral adiabatic inversion recovery technique for fat suppression (SPAIR) with proton density (PD) SPAIR in the detection of cervical MS plaques. Materials and methods Twenty five patients with clinically confirmed MS were examined on a 3.0T MR system. T2 and PD TSE SPAIR sequences were obtained in sagittal plane, using the same in plane resolution and slice thickness. The images set were assessed by two independent observers for the lesion detectability and image quality. Quantitative measurements of lesion-to-cord contrast ratio and lesion-contrast-to-noise ratio were obtained. All the lesions were verified with axial T2 multi echo gradient echo images. Results Fifteen of the scanned patients had MS lesion detected. PD_TSE_SPAIR sequence was most efficient in detection of MS lesions, demonstrated increased lesion contrast ratios about 15%, and also provided better image quality than T2_TSE_SPAIR. Twenty percent of lesions (3/20) that were not statistically significantly different from background cord signal on the T2 sequence. Conclusion PD_TSE_SPAIR sequence had high sensitivity to the detection of MS lesions compared to T2_TSE_SPAIR and should be included in the core sequences to the spinal MRI protocol for the assessment of suspected demyelinating disease. Disclosure There is not any disclosure.

Accuracy of Unenhanced MR Imaging in the Detection of Acute Appendicitis: Single-Institution Clinical Performance Review.

To determine the accuracy of unenhanced magnetic resonance (MR) imaging in the detection of acute appendicitis in patients younger than 50 years who present to the emergency department with right lower quadrant (RLQ) pain. The institutional review board approved this retrospective study of 403 patients from August 1, 2012, to July 30, 2014, and waived the informed consent requirement. A cross-department strategy was instituted to use MR imaging as the primary diagnostic modality in patients aged 3-49 years who presented to the emergency department with RLQ pain. All MR examinations were performed with a 1.5- or 3.0-T system. Images were acquired without breath holding by using multiplanar half-Fourier single-shot T2-weighted imaging without and with spectral adiabatic inversion recovery fat suppression without oral or intravenous contrast material. MR imaging room time was measured for each patient. Prospective image interpretations from clinical records were reviewed to document acute appendicitis or other causes of abdominal pain. Final clinical outcomes were determined by using (a) surgical results (n = 77), (b) telephone follow-up combined with review of the patient's medical records (n = 291), or (c) consensus expert panel assessment if no follow-up data were available (n = 35). Logistic regression analysis was performed to evaluate the sensitivity and specificity of MR imaging in the detection of acute appendicitis, and corresponding 95% confidence intervals were determined. Of the 403 patients, 67 had MR imaging findings that were positive for acute appendicitis, and 336 had negative findings. MR imaging had a sensitivity of 97.0% (65 of 67) and a specificity of 99.4% (334 of 336). The mean total room time was 14 minutes (range, 8-62 minutes). An alternate diagnosis was offered in 173 (51.5%) of 336 patients. MR imaging is a highly sensitive and specific test in the evaluation of patients younger than 50 years with acute RLQ pain that uses a rapid imaging protocol performed without intravenous or oral contrast material.

Detecting Peripheral Nerves in the Elbow using Three-Dimensional Diffusion-Weighted PSIF Sequences: a Feasibility Pilot Study

Purpose: To analyze the feasibility of three-dimensional (3D) diffusion-weighted (DW) PSIF (reversed FISP [fast imaging with steady-state free precession]) sequence in order to evaluate peripheral nerves in the elbow. Materials and Methods: Ten normal, asymptomatic volunteers were enrolled (6 men, 4 women, mean age 27.9 years). The following sequences of magnetic resonance images (MRI) of the elbow were obtained using a 3.0-T machine: 3D DW PSIF, 3D T2 SPACE (sampling perfection with application optimized contrasts using different flip angle evolution) with SPAIR (spectral adiabatic inversion recovery) and 2D T2 TSE (turbo spin echo) with modified Dixon (m-Dixon) sequence. Two observers used a 5-point grading system to analyze the image quality of the ulnar, median, and radial nerves. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of each nerve were measured. We compared 3D DW PSIF images with other sequences using the Wilcoxon-signed rank test and Friedman test. Inter-observer agreement was measured using intraclass correlation coefficient (ICC) analysis. Results: The mean 5-point scores of radial, median, and ulnar nerves in 3D DW PSIF (3.9/4.2/4.5, respectively) were higher than those in 3D T2 SPACE SPAIR (1.9/2.8/2.8) and 2D T2 TSE m-Dixon (1.7/2.8/2.9) sequences (P < 0.05). The mean SNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR, but there was no difference between 3D DW PSIF and 2D T2 TSE m-Dixon in all of the three nerves. The mean CNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR and 2D T2 TSE m-Dixon in the median and ulnar nerves, but no difference among the three sequences in the radial nerve. Conclusion: The three-dimensional DW PSIF sequence may be feasible to evaluate the peripheral nerves around the elbow in MR imaging. However, further optimization of the image quality (SNR, CNR) is required.

Magnetic Resonance Neurography of the Lumbar Plexus at the L4–5 Disc: Development of a Preoperative Surgical Planning Tool for Lateral Lumbar Transpsoas Interbody Fusion (LLIF)

Introduction The lateral transpsoas approach for lumbar interbody fusion (LLIF) is a minimally invasive surgical technique that is now frequently used to treat common spinal disorders. During LLIF, the course of the plexus within the surgical corridor places it at risk for iatrogenic intraoperative injury. Several previous studies have suggested that the risk of neurological injury during LLIF is higher at L4–L5. Current imaging techniques of assessing the proximity of neural tissue to the L4–L5 disc space have limited capabilities. Magnetic resonance neurography (MRN) is a noninvasive MR imaging tool developed for peripheral nerve imaging. A myriad of clinical applications exist including imaging assessment of lumbosacral plexopathies. In this study, we explored an additional clinical application for this technology as a preoperative planning tool for LLIF. Material and Methods Consecutive lumbar plexus MR neurograms ( n = 27 patients, 54 sides) were studied. All scans were performed on a Siemens 3 T Skyra MRI scanner. The imaging protocol included axial and coronal T1-weighted, axial and coronal T2-weighted spectral adiabatic inversion recovery (SPAIR; Siemens Healthcare), and coronal T2-weighted 3D inversion recovery (3D SPACE; Siemens Healthcare) sequences. Following acquisition, the images were postprocessed using TeraRecon Aquarius iNtuition v4.4 to generate T1- and T2- color-coded fusion maps. 3D models of the lumbosacral plexus with attention to the L4–L5 interspace were generated using the GE AW Suite v2 (General Electric). The L4–L5 intervertebral space was divided into six zones according to Moro method. Zones I to IV were distributed equidistantly between the anterior and posterior margins. The position of the plexus and the shape of the psoas muscle at the L4–L5 interspace was evaluated and recorded. Results Direct imaging of the lumbar plexus using MR neurography revealed variability in the position of the plexus relative to the L4–L5 interbody space. In this series of 27 patients, there was significant variability in the anatomic position of the lumbar plexus from patient-to-patient and right-to-left in individual patients. The left-side lumbar plexus was identified in zones III (55%) and zone IV (44%) ( p = 0.56). On the right side the plexus was most frequently identified in zones III (44%) or zone IV (44%) however was also identified in zone II (7.4%) or posterior (3.7%) ( p = 0.009). Right–left symmetry of the plexus relative to the disc space was found in 44% of the subjects. There was no correlation between the position of the plexus and the shape the overlying psoas muscle identified. Conclusion MRN is a noninvasive imaging technique for visualizing the lumbosacral plexus. The course of the lumbosacral plexus traversing the L4–5 disc space may be more variable than has been suggested by previous studies. MRN may provide a more reliable means of preoperatively identifying the plexus when compared with current methods. The ability to assess the location of the plexus may aid in preoperative planning and reduce neurological complications.

Breast DWI at 3 T: influence of the fat-suppression technique on image quality and diagnostic performance

To evaluate two fat-suppression techniques: short tau inversion recovery (STIR) and spectral adiabatic inversion recovery (SPAIR) regarding image quality and diagnostic performance in diffusion-weighted imaging (DWI) of breast lesions at 3 T. Ninety-two women (mean age 48 ± 12.1 years; range 21-78 years) underwent breast MRI. Two DWI pulse sequences, with b-values (50 and 1000 s/mm(2)) were performed with STIR and SPAIR. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), suppression homogeneity, and apparent diffusion coefficient (ADC) values were quantitatively assessed for each technique. Values were compared between techniques and lesion type. Receiver operating characteristics (ROC) analysis was used to evaluate lesion discrimination. One hundred and fourteen lesions were analysed (40 benign and 74 malignant). SNR and CNR were significantly higher for DWI-SPAIR; fat-suppression uniformity was better for DWI-STIR (p < 1 × 10(-4)). ADC values for benign and malignant lesions and normal tissue were 1.92 × 10(-3), 1.18 × 10(-3), 1.86 × 10(-3) s/mm(2) for DWI-STIR and 1.80 × 10(-3), 1.11 × 10(-3), 1.79 × 10(-3) s/mm(2) for SPAIR, respectively. Comparison between fat-suppression techniques showed significant differences in mean ADC values for benign (p = 0.013) and malignant lesions (p = 0.001). DWI-STIR and -SPAIR ADC cut-offs were 1.42 × 10(-3) and 1.46 × 10(-3) s/mm(2), respectively. Diagnostic performance for DWI-STIR versus SPAIR was: accuracy (81.6 versus 83.3%), area under curve (87.7 versus 89.2%), sensitivity (79.7 versus 85.1%), and specificity (85 versus 80%). Positive predictive value was similar. The fat-saturation technique used in the present study may influence image quality and ADC quantification. Nevertheless, STIR and SPAIR techniques showed similar diagnostic performances, and therefore, both are suitable for use in clinical practice.

상완신경총 환자에서 최적의 자기공명영상 지방소거 기법에 관한 연구 : SPAIR, STIR 지방소거 중심으로

상완신경총에서 STIR(short TI inversion recovery) 지방소거 강조영상과 SPAIR(spectral adiabatic inversion recovery) T2, T1 지방소거 강조영상기법을 비교 평가하여 최적의 지방소거 기법을 알아보고자 하였다. 총 30 명 상완신경총에 질환이 없는 정상인 지원자를 대상으로 3.0 T MRI 기기를 이용하여 검사를 하였고, 분석방법으로 세 기법에 대하여 SNR, CNR 및 4단계 점수로 평가를 하였다. 정량적 분석 결과로 SPAIR T1 기법에 대한 SNR, CNR 값은 상완신경총기시부(<TEX>$03.07{\pm}0.98$</TEX>, <TEX>$-2.25{\pm}0.54$</TEX>), 상완신경총몸체(<TEX>$06.70{\pm}1.81$</TEX>, <TEX>$36.31{\pm}2.17$</TEX>)에서 높은 값을 제공하였다 (p<0.05). 정성적 분석결과 상완신경총 묘출도와 지방소거 정도, 영상의 인공물은 SPAIR T1(<TEX>$3.2{\pm}0.70$</TEX>, <TEX>$3.6{\pm}0.51$</TEX>, <TEX>$3.4{\pm}0.10$</TEX>)기법이 의미 있게 높게 나타났다(p<0.05). The purpose of this study is to know optimized fat suppression techniques for brachial plexus compared with STIR and SPAIR T1, T2 techniques. A total of 30 normal volunteers without brachial plexus disease were studied on a 3.0 T MRI scanner. As an analytical method, SNR, CNR, 4-point grading scale were evaluated by using three pulse sequences. As a quantitative analysis, the SNR, CNR for SPAIR T1 technique provided high value in branchial plexus roots (03.07, -2.25), branchial plexus trunks(06.70, 36.31)(p<0.05). As a qualitative Analysis, The visibility for delineation of brachial plexus, fat suppression, artifact was significantly better on SPAIR T1(3.2, 3.6, 3.4) technique(p<0.05).

Phantom for assessment of fat suppression in large field-of-view diffusion-weighted magnetic resonance imaging

We present the development and application of a phantom for assessment and optimization of fat suppression over a large field-of-view in diffusion-weighted magnetic resonance imaging at 1.5 T and 3 T. A Perspex cylinder (inner diameter 185 mm, height 300 mm) which contains a second cylinder (inner diameter 140 mm) was constructed. The inner cylinder was filled with water doped with copper sulphate and sodium chloride and the annulus was filled with corn oil, which closely matches the spectrum and longitudinal relaxation times of subcutaneous abdominal fat. Placement of the phantom on the couch at 45° to the z-axis presented an elliptical cross-section, which was of a similar size and shape to axial abdominal images. The use of a phantom for optimization of fat suppression allowed quantitative comparison between studies without the differences introduced by variability between human subjects. We have demonstrated that the phantom is suitable for selection of inversion delay times, spectral adiabatic inversion recovery delays and assessment of combinatorial methods of fat suppression. The phantom is valuable in protocol development and the assessment of new techniques, particularly in multi-centre trials.

MR‐guided sclerotherapy of low‐flow vascular malformations using T2‐weighted interrupted bSSFP (T2W‐iSSFP): Comparison of pulse sequences for visualization and needle guidance

Image-guided treatment of low-flow vascular (venous or lymphatic) malformations presents a challenging visualization problem, regardless of the imaging modality being used for guidance. The purpose of this study was to employ a new magnetic resonance imaging (MRI) sequence, T2 -weighted interrupted balanced steady-state free precession (T2 W-iSSFP), for real-time image guidance of needle insertion. T2 W-iSSFP uses variable flip angle balanced steady-state free precession (bSSFP, a.k.a. SSFP) to establish T2 -weighting and fat suppression. Swine (n = 3) and patients (n = 4, three female, all with venous malformations) were enrolled in the assessment. T2 -weighted turbo spin echo (T2 -TSE) with spectral adiabatic inversion recovery (SPAIR), SPAIR-T2 -TSE or T2 -TSE for short, was used as the reference. T2 -weighted half Fourier acquired single shot turbo spin echo (T2 -HASTE) with SPAIR (SPAIR-T2 -HASTE, T2 -HASTE for short), fat saturated bSSFP (FS-SSFP), and T2 W-iSSFP were imaged. Numeric metrics, namely, contrast-to-noise ratio (CNR) efficiency (CNR divided by the square root of acquisition time) and local sharpness (the reciprocal of edge width), were used to assess image quality. MR-guided sclerotherapy was performed on the same patients using real-time T2 W-iSSFP to guide needle insertion. Comparing the visualization of needles in the images of swine, the local sharpness (mm(-1) ) was: 0.21 ± 0.06 (T2 -HASTE), 0.48 ± 0.02 (FS-SSFP), and 0.49 ± 0.03 (T2 W-iSSFP). T2 W-iSSFP is higher than T2 -HASTE (P < 0.001). For the patient images, their CNR efficiencies were: 797 ± 66 (T2 -HASTE), 281 ± 44 (FS-SSFP), and 860 ± 29 (T2 W-iSSFP). T2 W-iSSFP is higher than FS-SSFP (P < 0.02). The frame rate of T2 W-iSSFP was 2.5-3.5 frames per second. All MR-guided sclerotherapy procedures were successful, with all needles (six punctures) placed in the targets. T2 W-iSSFP provides effective lesion identification and needle visualization. This new pulse sequence can be used for MR-guided sclerotherapy of low-flow vascular malformations. It may have potential use in other MR-guided procedures where heavily T2 -weighted real-time images are needed.