T2-weighted Fast Spin-echo Research Articles

Diagnostic Performance and Reliability of Non-Enhanced Imaging Characterization Quotients for the Differentiation of Infectious andMalignant Pulmonary Nodules in Hematological Patients Using 3T MRI.

To evaluate the diagnostic performance and reliability of non-enhanced imaging characterization quotients (NICQs) derived from magnetic resonance imaging (MRI) in the differential diagnosis of pulmonary nodules in hematological patients. A total of 83 lesions in 45 consecutive hematological patients were analyzed (10 bacterial pneumonias, 16 fungal pneumonias, 19 pulmonary lymphoma manifestations). The MRI protocol included T2-weighted single-shot fast spin echo (FSE) and T1-weighted gradient echo (GRE) sequences. T2-based T2-NICQmean and T2-NICQ90th were calculated from signal intensities measured in the lesion, muscle, and fat ((SILesion - SIMuscle)/(SIFat - SIMuscle) * 100), and simple T1-based T1-Qmean from signal intensities of the lesion and muscle (SILesion/SIMuscle). Images were read by one radiologist with > 7 years and one with 1year of experience. For statistical evaluation the Kruskal-Wallis or Mann-Whitney U-test, receiver operating characteristic (ROC) analysis with calculation of areas under the curve (AUC), and intraclass correlation coefficients (ICCs) were used. Medians of T2-NICQs differed significantly when comparing infectious lesions and lymphoma manifestations in general (T2-NICQmean 20.33 vs. 10.14; T2-NICQ90th 34.96 vs. 25.52) or fungal lesions and lymphoma manifestations in particular (T2-NICQmean 19.00 vs. 10.14; T2-NICQ90th 34.49 vs. 25.25). The AUCs for T2-NICQs on the per-patient level ranged from 0.73 to 0.79. ICCs were at least > 0.85, except for intrarater testing of T2-NICQ90th (0.79). The overall diagnostic performance of T2-NICQs is adequate for differentiating infectious and fungal lesions from lymphoma manifestations. The results show good to excellent intra- and interrater agreement. We therefore consider NICQs helpful in the diagnostic workup of pulmonary nodules in hematological patients. · Non-enhanced Imaging Characterization Quotients provide a fast and pragmatic approach for assessing pulmonary lesions in hematological patients.. · The diagnostic performance of Non-enhanced Imaging Characterization Quotients is adequate for differentiating infectious and fungal infiltrates from lymphoma manifestations.. · Non-enhanced Imaging Characterization Quotients show good to excellent intra- and interrater agreement.. · Nagel SN, Kim D, Wylutzki T et al. Diagnostic Performance and Reliability of Non-Enhanced Imaging Characterization Quotients for the Differentiation of Infectious and Malignant Pulmonary Nodules in Hematological Patients Using 3T MRI. Fortschr Röntgenstr 2020; 192: 327 - 334.

Evaluating the Origin of the Brain Metastatic Tumors by Using DWI Parameters

Background: Brain metastases are the most common tumors in the human central nervous system (CNS), with an occurrence 10 times higher than primary brain tumors in adults. A radiologist usually diagnoses these tumors. Typically, magnetic resonance imaging (MRI) has been used to evaluate the status and number of metastases, the design of surgical treatment or radiotherapy, and the response to treatment. This study aimed to consider the origin of metastatic tumors of the brain using diffusionweighted imaging sequence. Methods: In this study, 95 lesions observed in 51 patients with different types of brain metastasis who analyzed with standard brain MRI protocols such as T2-weighted fast spin-echo in sagittal, coronal and axial planes and T1-weighted spin-echo sequences before and after injection of contrast enhancement and diffusion-weighted imaging. The diffusion-weighted imaging included an echoplanar spin-echo sequence with two b values (0,1000 s/mm) and calculated apparent diffusion coefficient (ADC) maps. We measured the ADC-value on normalized ADC maps and compared them with different methods. ANOVA was used to compare ADC among all groups as well as T-test for every two groups. Results: The results showed that patients with lung cancer (squamous cell carcinoma, SCC) had the lowest mean ADC (658.70*10-3 mm2 /s) and breast cancer patients with the highest mean ADC(935.52*10-3 mm2 /s). This study demonstrated that most Brain metastases had low and intermediate ADC values. The analysis showed no significant difference among all groups. However, ADC values in breast cancer and kidney and lung (adenocarcinoma) were statistically higher in comparison to other groups. There were no critical discrepancies between ADC values in brain metastases from Breast cancer and lung cancer (adenocarcinoma) and kidney. Conclusion: It seems that evaluating the origin of the brain metastatic tumors by using diffusion imaging (DWI) parameters could be helpful to prevent invasive methods like biopsies in some situations. Although it needs more studies to achieve this purpose.

Natural embryonic death in the plain viscacha Lagostomus maximus: are there previous anatomo-histological variations that would intervene in the differential survival of the implantations?

Visualization of the retroplacental clear space (RPCS) may provide critical insight into the development of abnormally invasive placenta (AIP). In this pre-clinical study, we characterized the appearance of the RPCS on magnetic resonance imaging (MRI) during the second half of gestation using a liposomal gadolinium contrast agent (liposomal-Gd).Studies were performed in fifteen pregnant C57BL/6 mice at 10, 12, 14, 16, and 18 days of gestation. MRI was performed on a 1T permanent magnet scanner. Pre-contrast and post-contrast images were acquired using T1-weighted gradient-recalled echo (T1w-GRE) and T2-weighted fast spin echo (T2w-FSE) sequences. Animals were euthanized after imaging and feto-placental units harvested for histological examination. Visualization of the RPCS was scored by a maternal-fetal radiologist and quantified by measuring the contrast-to-noise ratio (CNR) on T1w images. Feto-placental features were segmented for analysis of volumetric changes during gestation.Contrast-enhanced T1w images enabled the visualization of structural changes in placental development between days 10–18 of gestation. Although the placental margin on the fetal side was clearly visible at all time points, the RPCS was partially visible at day 10 of gestation, and clearly visible by day 12. Hematoxylin and eosin (H&E) staining of the placental tissue corroborated MRI findings of structural and morphological changes in the placenta.Contrast-enhanced MR imaging using liposomal-Gd enabled adequate visualization of the retroplacental clear space starting at day 12 of gestation. The agent also enabled characterization of placental structure and morphological changes through gestation.

High-resolution MRI using compressed sensing-sensitivity encoding (CS-SENSE) for patients with suspected neurovascular compression syndrome: comparison with the conventional SENSE parallel acquisition technique

To retrospectively compare sensitivity encoding (SENSE) and compressed sensing-sensitivity encoding (CS-SENSE) for high resolution (HR) cranial nerve magnetic resonance imaging (MRI) in a clinical population. Twenty consecutive patients who were clinically suspected of neurovascular compression syndrome (NVCS) were enrolled in this study. HR three-dimensional isotropic T2-weighted fast spin-echo (T2 VISTA) sequences with SENSE or CS-SENSE, and contrast-enhanced three-dimensional T1-turbo field-echo (CE 3D T1 TFE) with SENSE or CS-SENSE, were compared using quantitative and qualitative methods by two board-certified neuroradiologists. For the T2 VISTA, CS-SENSE was significantly superior to SENSE in terms of cerebrospinal fluid homogeneity. For CE 3D T1 TFE, CS-SENSE was significantly superior to SENSE in terms of the existence of ghost artefact and the signal-to-noise ratio (SNR) of the pontine parenchyma. There was no significant difference in overall image quality between the two techniques. Compared with SENSE, CS-SENSE reduced the scan time to 44.2% of that with SENSE on T2 VISTA, and to 66.1% of that with SENSE of the CE 3D T1 TFE, with the differences being statistically significant (p<0.01, both). For T2 VISTA and CE 3D T1 TFE imaging of patients with suspected NVCS, CS-SENSE appears to offer superior reductions in motion artefact and scan time relative to SENSE, without a loss of overall image quality.

Low b-value (50-100) diffusion-weighted images detect significantly more hyperintense liver lesions in children than T2-weighted images.

Low b-value (50-100s/mm2) diffusion-weighted images (low b-value DWI) have been shown to be superior to T2-weighted fast spin echo sequence (T2-W) in detecting liver lesions in adults. There are no such studies assessing this difference in children. The purpose of the study was to compare the sensitivity of low b-value DWI images and T2-W images in detecting focal liver lesions in children. A retrospective review of liver magnetic resonance imaging (MRI) to assess focal liver lesions in 50 children (22 males, 28 females; age: 2months to 17years [mean: 10.9years]) was performed. Two radiologists reviewed both low b-value DWI and T2-W sequences independently on different occasions to note lesions, the smallest lesion size and the location. A consensus reading of the entire MRI examination and a correlation with follow-up, other imaging modalities and pathology in available cases were used to determine the final number of lesions as a reference standard. The average number of lesions per patient detected by both readers on each sequence was compared with each other and with the reference standard using the signed-rank test. The smallest lesions detected by each sequence were compared using the paired t-test. One hundred seventy hyperintense lesions were identified on consensus review to serve as the reference standard. The average number of lesions identified by both readers on low b-value DWI was 134 (79%) and on T2-W was 95 (56%). There was excellent interobserver agreement for detection of lesions on low b-value DWI (intraclass correlation coefficient [ICC]=0.96 [0.93-0.98]) and T2-W (ICC=0.85 [0.75-0.91]), with slightly better agreement on low b-value DWI. Both readers identified significantly more number of lesions on low b-value DWI compared to T2-W (Reader 1: P=0.0036, Reader 2: P=0.0001). Compared to the reference standard (mean number of lesions: 3.45), T2-W detected significantly fewer lesions (mean number of lesions: 1.91; P=0.0001) while there was no significant difference in lesion detection on low b-value DWI (mean number of lesions: 2.68; P=0.1527). Low b-value DWI and T2-W were not significantly different in identifying the smallest lesion size (Reader 1: P=0.19, Reader 2: P=0.47). Low b-value DWI images are more sensitive than T2-W sequences in detecting hyperintense focal liver lesions in children.

Evaluation of magnetic susceptibility artefact induced by personal care product with gold nanoparticles on brain magnetic resonance (MRI) images

MRI is an important diagnostic imaging tool as it provides excellent soft tissue contrast resolution. Artefact in MRI is an undesirable appearance in the image that affect the image quality and may hinder true diagnosis of the pathological events. Gold in bulk form does not cause any artefact in MRI as it is diamagnetic whereas in its nanoscale version, it was proven to pose magnetic properties. Previous studies also shown that some personal care products (PCPs) produce artefact in MR images due to the presence of metallic compounds in the PCP. Hence, this study was conducted to investigate the effect of PCP with gold nanoparticles (AuNPs) on brain MRI images. The study was conducted using 1.5 Tesla MRI system where moisturiser and compact powder with AuNPs were tested. The products were applied onto the micropore tape attached to the MRI water phantom. The phantom was placed in an RF coil at the isocentre of the MRI bore and scanned using T1-weighted fast-spin-echo (FSE), T2-weighted FSE and fluid attenuated inversion recovery (FLAIR) sequences. The images were evaluated using Visual Grading Analysis (VGA) checklist by two radiologists. Based on the VGA score, brain MRI images in moisturiser group were all scored ‘1’ which indicate minimal artefact with only loss of fine details seen. Whereas, brain MRI images of compact powder group were all scored ‘0’ which indicate no artefact seen. Therefore, it can be concluded that PCP with AuNPs produce little to no artefact on brain MRI images, thus, there will be no need for the patient who wears PCP with AuNPs to clean their face prior to brain MRI examination.

Echo-planar FLAIR Sequence Improves Subplate Visualization in Fetal MRI of the Brain.

Background The cortical plate (future cortex) is readily identifiable in utero at MRI. However, MRI evaluation of the remaining brain layers is limited by the poor T2 contrast between the subplate and the underlying intermediate zone (IZ). Purpose To compare the delineation of fetal brain lamination between T2-weighted single-shot fast spin-echo (SSFSE) and echo-planar imaging (EPI) fluid-attenuated inversion recovery (FLAIR) images, and to quantify differences in the depiction of brain layering between the two sequences. Materials and Methods Consecutive fetal brain MRI examinations performed between January 2014 and March 2018 with T2-weighted SSFSE and EPI-FLAIR images were reviewed. Two neuroradiologists evaluated the visibility of brain layers by using a three-point grading system, and findings were compared by using the sign test. One rater performed region-of-interest analysis in the cortical plate (CP), subplate (gyral crest and sulcal bottom), and IZ. Signal intensity (SI) ratios between adjacent brain compartments were calculated and compared by using the paired t test. Reader agreement was assessed by using weighted κ values. Results A total of 259 MRI examinations (mean gestational age [GA], 26.9 weeks ± 5.6) were included in the qualitative analysis, and 72 MRI examinations (mean GA, 27.4 weeks ± 5.5) were included in the quantitative analysis. Subplate identification on EPI-FLAIR images was superior to that on T2-weighted SSFSE images (subplate visualization [complete + partial]: frontal lobe, n = 243 vs n = 117; temporal lobe, n = 244 vs n = 137; parietal lobe n = 240 vs n = 93; and occipital lobe, n = 241 vs n = 97, respectively; P < .001), with higher interrater reliability (κ = 0.91-0.95 for EPI-FLAIR images and 0.80-0.87 for T2-weighted SSFSE images). SI ratios between the IZ and subplate were significantly higher on EPI-FLAIR images in all lobes (EPI-FLAIR images: 1.6-2.1; T2-weighted SSFSE images:1.2-1.2; P < .001). Subplate-to-CP ratios were not statistically significant between the two sequences (EPI-FLAIR:1.8-2.4; T2-weighted SSFSE: 2.0-2.2; P < .001). Conclusion The echo-planar fluid-attenuated inversion recovery sequence improves visualization of fetal brain lamination compared with the T2-weighted single-shot fast spin-echo sequence, as established by quantitative and qualitative methods. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Rossi in this issue.

Deep learning enables automatic detection and segmentation of brain metastases on multisequence MRI.

Detecting and segmenting brain metastases is a tedious and time-consuming task for many radiologists, particularly with the growing use of multisequence 3D imaging. To demonstrate automated detection and segmentation of brain metastases on multisequence MRI using a deep-learning approach based on a fully convolution neural network (CNN). Retrospective. In all, 156 patients with brain metastases from several primary cancers were included. 1.5T and 3T. [Correction added on May 24, 2019, after first online publication: In the preceding sentence, the first field strength listed was corrected.] SEQUENCE: Pretherapy MR images included pre- and postgadolinium T1 -weighted 3D fast spin echo (CUBE), postgadolinium T1 -weighted 3D axial IR-prepped FSPGR (BRAVO), and 3D CUBE fluid attenuated inversion recovery (FLAIR). The ground truth was established by manual delineation by two experienced neuroradiologists. CNN training/development was performed using 100 and 5 patients, respectively, with a 2.5D network based on a GoogLeNet architecture. The results were evaluated in 51 patients, equally separated into those with few (1-3), multiple (4-10), and many (>10) lesions. Network performance was evaluated using precision, recall, Dice/F1 score, and receiver operating characteristic (ROC) curve statistics. For an optimal probability threshold, detection and segmentation performance was assessed on a per-metastasis basis. The Wilcoxon rank sum test was used to test the differences between patient subgroups. The area under the ROC curve (AUC), averaged across all patients, was 0.98 ± 0.04. The AUC in the subgroups was 0.99 ± 0.01, 0.97 ± 0.05, and 0.97 ± 0.03 for patients having 1-3, 4-10, and >10 metastases, respectively. Using an average optimal probability threshold determined by the development set, precision, recall, and Dice score were 0.79 ± 0.20, 0.53 ± 0.22, and 0.79 ± 0.12, respectively. At the same probability threshold, the network showed an average false-positive rate of 8.3/patient (no lesion-size limit) and 3.4/patient (10 mm3 lesion size limit). A deep-learning approach using multisequence MRI can automatically detect and segment brain metastases with high accuracy. 3 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:175-182.

Case 269.

History A 20-year old woman living in Turkey presented with a 3-month history of lower back pain. She had no medical history of note and was taking no medications. Complete blood count, C-reactive protein level, sedimentation rate, and creatinine, alanine aminotransferase, and aspartate aminotransferase levels were within normal limits. Anteroposterior pelvic radiography and unenhanced pelvic CT were performed to rule out sacroiliitis. The imaging findings were abnormal, and the patient underwent contrast-enhanced sacroiliac MRI. A few days later, she underwent contrast-enhanced (100 mL iohexol, Omnipaque; GE Healthcare, Cork, Ireland) abdominal CT because of right upper quadrant pain. Figure 1: Anteroposterior pelvic radiograph. Figure 2: Axial unenhanced pelvic CT image. Figure 3a: (a) Coronal T2-weighted fat-saturated fast spin-echo (repetition time msec/echo time msec, 2220/57; section thickness, 4 mm), (b) axial unenhanced T1-weighted fat-saturated, and (c) axial contrast-enhanced (20 mL gadoteric acid, Dotarem; Guerbet, Roissy, France) T1-weighted fat-saturated (400/20; section thickness, 4 mm) sacroiliac images from MRI. Figure 3b: (a) Coronal T2-weighted fat-saturated fast spin-echo (repetition time msec/echo time msec, 2220/57; section thickness, 4 mm), (b) axial unenhanced T1-weighted fat-saturated, and (c) axial contrast-enhanced (20 mL gadoteric acid, Dotarem; Guerbet, Roissy, France) T1-weighted fat-saturated (400/20; section thickness, 4 mm) sacroiliac images from MRI. Figure 3c: (a) Coronal T2-weighted fat-saturated fast spin-echo (repetition time msec/echo time msec, 2220/57; section thickness, 4 mm), (b) axial unenhanced T1-weighted fat-saturated, and (c) axial contrast-enhanced (20 mL gadoteric acid, Dotarem; Guerbet, Roissy, France) T1-weighted fat-saturated (400/20; section thickness, 4 mm) sacroiliac images from MRI. Figure 4: Axial contrast-enhanced CT image of the abdomen.

Age, But Not Repeated Exposure to Gadoterate Meglumine, Is Associated With T1- and T2-Weighted Signal Intensity Changes in the Deep Brain Nuclei of Pediatric Patients.

Current findings on gadolinium deposition in the pediatric brain due to repeated exposure to macrocyclic contrast agents are inconclusive and possibly confounded by brain maturation processes. We evaluated the longitudinal effects of repeated gadoterate meglumine exposure (Dotarem; Guerbet, Villepinte, France) on the T1- and T2-weighted signal intensity (SI) in pediatric patients, and assessed the magnitude of age-related increase in T1-weighted (and decrease in T2-weighted) SI in a control cohort without prior gadolinium exposure. In this retrospective, double-cohort study, magnetic resonance imaging (MRI) data of 24 patients (0.7-16.4 years, M = 5.74, SD = 4.15) who received at least 10 doses of exclusively gadoterate meglumine were included in the longitudinal study. The MRI data of 190 controls (age range, 1-20 years; 10 patients/bin; bin width, 1 year) without any prior gadolinium-based contrast exposure were included in the control, cross-sectional study to assess the age-dependent SI changes in the regions of interest (ROIs). We measured SI (native), T1-weighted gradient echo, and T2-weighted fast spin-echo of 12 deep brain nuclei. The ROIs were measured at each of the first 11 MRI examinations of the contrast-exposed patients and in the control subject's MRI. Regions of interest's SIs, normalized by the pons, were analyzed with mixed effects models, accounting for the potential confounding factors, such as radiotherapy and chemotherapy. The number of gadoterate meglumine administrations had no effect on the SI increase in any of the ROIs (all P > 0.05), but age significantly correlated with increased SI in T1-weighted globus pallidus (GP; P < 0.01) and caudate (P < 0.05), and with decreased SI in T2-weighted GP (P < 0.001) and dentate nucleus (P < 0.005) in the contrast-exposed group. The cross-sectional analyses of the control cohort showed a significant age-dependent T1-weighted SI increase in multiple ROIs, including the GP and caudate, and decrease in the T2-weighted GP and dentate nucleus (P < 0.05). Repeated exposure to gadoterate meglumine was not associated with brain hyperintensity in the pediatric patients, whereas age importantly contributed to the SI changes in several deep brain nuclei.

The usefulness of the oblique coronal plane of three-dimensional isotropic T2-weighted fast spin-echo (VISTA) knee MRI in the evaluation of posterior cruciate ligament reconstruction with allograft: Comparison with the oblique coronal plane of two-dimensional fast spin-echo T2-weighted sequences

PurposeWe compared two imaging techniques to assess whether 3D VISTA imaging could replace 2D FSE in diagnosing PCL reconstruction complications. Materials and methodsThis retrospective study included 40 patients who underwent surgery of PCL reconstruction and follow-up knee MRI (3D VISTA and 2D FSE) for evaluation of PCL graft integrity. Each image was interpreted independently by two radiologists without knowledge of radiologic reports or clinical history. The diagnostic performance of the 2D FSE PCL view, 3D VISTA PCL view, orthogonal 2D FSE image, and combined sequences were evaluated in terms of sensitivity, specificity, and accuracy for diagnosing complications of PCL graft. The reference diagnoses were made arthroscopically or clinically. ResultsThe sensitivities of the 3D VISTA PCL view were similar to those of the 2D PCL view. The sensitivities of the combination of the orthogonal view and the 3D VISTA PCL view were also similar to those of the combination of the orthogonal view and the 2D PCL view. The specificities and accuracies of each image exhibited similar results. There was no statistically significant difference in diagnostic performance between the 3D VISTA PCL view and the 2D PCL view (solitary or combined with the orthogonal view). ConclusionsThe diagnostic performance of the PCL views on 3D VISTA images is comparable to that of 2D FSE images in the diagnosis of PCL graft complications.

Validation of contrast enhanced cine steady-state free precession and T2-weighted CMR for assessment of ischemic myocardial area-at-risk in the presence of reperfusion injury.

The purpose of the study was to validate by histopathology, contrast enhanced cine steady-state free precession and T2-weighted CMR for the assessment of ischemic myocardial area-at-risk (AAR) in the presence of microvascular obstruction (MVO). Eleven anesthetized pigs underwent CMR 7 to 10 days post infarction. The area-at-risk was measured from T2-weighted fast spin echo (T2-STIR) and contrast-enhanced steady-state free precession magnetic resonance imaging (CE-SSFP) images using semi-automated algorithms based on a priori knowledge of perfusion territory. Also, late gadolinium enhancement (LGE) was performed to measure final infarct size (FIS). Histopathological comparison with Evans blue dye to define AAR and triphenyltetrazolium chloride to define FIS served as the reference. All infarcts demonstrated MVO on LGE images. Bland-Altman analysis showed no significant bias in AAR or myocardial salvage between T2-STIR and CE-SSFP or between CMR and histopathology. The mean differences ± 2SD from Bland-Altman analysis were: AAR: Evans Blue vs. T2-STIR [0.7%; +13.5%; -12.1%]; AAR: Evans Blue vs. CE-SSFP [0.1%; +13.8%; -13.7%]; AAR: T2-STIR vs. CE-SSFP [0.7%; +6.2%; -4.9%]; Salvage: Evans Blue-TTC vs. T2-STIR-LGE [0.8%; +11.1%; -9.6%]; Salvage: Evans Blue-TTC vs. CE-SSFP-LGE [0.1%; +9.9%; -9.6%]; Salvage: CE-SSFP-LGE vs. T2-STIR-LGE [0.7%; +6.2%; -4.9%]. Both T2-STIR and CE-SSFP sequences allow for unbiased quantification of AAR in the presence of ischemia/reperfusion injury when analysed by semi-automated algorithms. These experimental data, which was validated by histopathology, supports the use of CMR for the assessment of myocardial salvage during the subacute phase.

Spectrum of Magnetic Resonance imaging in Afebrile Pediatric Epilepsy

Background: Pediatric neurological disorders are commonly encountered. Epilepsy is one of the most common neurological disorder in childhood. Clinically diagnosis is established by two or more unprovoked seizures at least 24 hours apart. It has got considerable importance due to fact that it can cause anxiety in parents. Cortical malformations characterized by abnormal structure of cerebral cortex are one of the major cause for epilepsy. Magnetic resonance imaging is the modality of choice to evaluate the structural anomaly, the cause of seizure disorder and to assess the potential need for surgery. In this study, we tried to evaluate the spectrum of MRI imaging to evaluate afebrile pediatric epilepsy. Subjects and Methods: The study was retrospective cross sectional study. We collected data of 400 patients of pediatric epilepsy who underwent non contrast MRI evaluation during June 2017 to January 2019 at department of Radio-diagnosis at GCS Medical college, Hospital and Research Center. Exclusion criteria consist of a recent history of fever and clinical laboratory parameters of any infective cause. MRI was done using 1.5 Tesla equipment. Sequences included Sagittal T1-weighted spin echo (SE), Axial T2-weighted fast spin echo (FSE), Coronal oblique fast fluid attenuated inversion recovery (FLAIR), Axial diffusion weighted single-shot spin-echo echoplanar, Axial 3D inversion recovery prepped fast SPGR (spoiled gradient recalled). Results: The most common detected changes were unilateral and bilateral mesial temporal sclerosis (21% & 9% respectively), cortical dysplasia (1.5%), migrational anomalies, neurocutaneous syndromes and few cortical neoplasms (0.5 to 1%). Conclusion: MRI in today's world plays a deciding role in diagnostic work-up of a child with epilepsy.

Pre-clinical magnetic resonance imaging of retroplacental clear space throughout gestation

IntroductionVisualization of the retroplacental clear space (RPCS) may provide critical insight into the development of abnormally invasive placenta (AIP). In this pre-clinical study, we characterized the appearance of the RPCS on magnetic resonance imaging (MRI) during the second half of gestation using a liposomal gadolinium contrast agent (liposomal-Gd). Materials and methodsStudies were performed in fifteen pregnant C57BL/6 mice at 10, 12, 14, 16, and 18 days of gestation. MRI was performed on a 1T permanent magnet scanner. Pre-contrast and post-contrast images were acquired using T1-weighted gradient-recalled echo (T1w-GRE) and T2-weighted fast spin echo (T2w-FSE) sequences. Animals were euthanized after imaging and feto-placental units harvested for histological examination. Visualization of the RPCS was scored by a maternal-fetal radiologist and quantified by measuring the contrast-to-noise ratio (CNR) on T1w images. Feto-placental features were segmented for analysis of volumetric changes during gestation. ResultsContrast-enhanced T1w images enabled the visualization of structural changes in placental development between days 10–18 of gestation. Although the placental margin on the fetal side was clearly visible at all time points, the RPCS was partially visible at day 10 of gestation, and clearly visible by day 12. Hematoxylin and eosin (H&E) staining of the placental tissue corroborated MRI findings of structural and morphological changes in the placenta. ConclusionsContrast-enhanced MR imaging using liposomal-Gd enabled adequate visualization of the retroplacental clear space starting at day 12 of gestation. The agent also enabled characterization of placental structure and morphological changes through gestation.

In Vivo 3D MRI Measurement of Tumour Volume in an Orthotopic Mouse Model of Prostate Cancer.

Prostate cancer (CaP) is the most commonly diagnosed cancer in males in western countries. Orthotopic implantation is considered as an ideal xenograft model for CaP study, and noninvasive measurement of tumor volume changes is important for monitoring responses to anticancer therapies. In this study, the T2-weighted fast spin echo sequence magnetic resonance imaging (MRI) was performed on a CaP orthotopic non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mouse model weekly for 6 weeks post PC-3 CaP cell inoculation, and the fat signal was suppressed using a chemical shift-selective pulse. Subsequently, the MRI data were imported into the image processing software Avizo Standard and stacked into three-dimensional (3D) volumes. Our results demonstrate that MRI, combined with 3D reconstruction, is a feasible and sensitive method to assess tumor growth in a PC-3 orthotopic CaP mouse model and this established monitoring approach is promising for longitudinal observation of CaP xenograft development after anticancer therapy in vivo. Further investigation is needed to validate this protocol in a larger cohort of mice to generate enough statistical power.

Dynamic magnetic resonance imaging of carbogen challenge on awake rabbit brain at 1.5T.

Anesthesia may alter the cellular components contributing to the magnetic resonance imaging (MRI) signal intensities. Developing awake animal models to evaluate cerebral function has grown in importance. To investigate a noninvasive strategy for dynamic MRI (dMRI) of awake rabbits during carbogen challenge. A nonmetallic assistive device with a self-adhering wrap secure procedure was developed for the head fixation of awake rabbits. Multi-shot gradient echo echo-planar imaging sequence was applied for the dMRI on a 1.5 T clinical MRI scanner with a quadrature head coil. The carbogen challenge pattern was applied in a sequence of air - carbogen - air - carbogen - air. Twelve scans were performed for each block of carbogen challenge. T2-weighted fast-spin echo and T1-weighted gradient echo sequences were performed before and after dMRI to evaluate the head position shifts. The whole dMRI scan time was about 30 minutes. The position shift of 8 rabbits in the x-and y-direction was less than 3%. The average MRI signal intensities (SI) from the 8 rabbits during carbogen challenge was fitted well using exponential growth and decay functions. The average MRI SI increase due to carbogen inhaling was 1.51%. The proposed strategy for head dMRI on an awake rabbit during carbogen challenge is feasible.

Value of Texture Analysis on Gadoxetic Acid-Enhanced MRI for Differentiating Hepatocellular Adenoma From Focal Nodular Hyperplasia.

The objective of our study was to assess the diagnostic performance of texture analysis (TA) on gadoxetic acid-enhanced MR images for differentiation of hepatocellular adenoma (HCA) from focal nodular hyperplasia (FNH). This study included 40 patients (39 women and one man) with 51 HCAs and 28 patients (27 women and one man) with 32 FNH lesions. All lesions were histologically proven with preoperative MRI performed with gadoxetic acid. Two readers reviewed all the imaging sequences to assess the qualitative MRI characteristics. The T2-weighted fast spin-echo, hepatic arterial phase (HAP), and hepatobiliary phase (HBP) sequences were used for TA. Textural features were extracted using commercially available software (TexRAD). The differences in distributions of TA parameters of FNHs and HCAs were assessed using the Mann-Whitney U test. Area under the ROC curve (AUROC) values were calculated for statistically significant features. A logistic regression analysis was conducted to explore the added value of TA. A p value < 0.002 was considered statistically significant after Bonferroni correction for multiple comparisons. Multiple TA parameters showed a statistically different distribution in HCA and FNH including skewness on T2-weighted imaging, skewness on HAP imaging, skewness on HBP imaging, and entropy on HBP imaging (p < 0.001). Skewness on HBP imaging showed the largest AUROC (0.869; 95% CI, 0.777-0.933). A skewness value on HBP imaging of greater than -0.06 had a sensitivity of 72.5% and a specificity of 90.6% for the diagnosis of HCA. Six of 51 (11.8%) HCAs lacked hypointensity on HBP imaging. A binary logistic regression analysis including hypointensity on HBP imaging and the statistically significant TA parameters yielded an AUROC of 0.979 for the diagnosis of HCA and correctly predicted 96.4% of the lesions. TA may be of added value for the diagnosis of atypical HCA presenting without hypointensity on HBP imaging.

Magnetic resonance imaging features of pubic symphysis urinary fistula with pubic bone osteomyelitis in the treated prostate cancer patient.

Pubic bone osteomyelitis with pubic symphysis urinary fistula represents a debilitating complication of radiation and ablative treatments for prostate cancer. The definitive radiographic diagnosis of this clinical entity is not described. In this study, we characterize the plain film and magnetic resonance imaging findings of pubic osteomyelitis. We reviewed a database of prostate cancer survivors with diagnosed pubic osteomyelitis from 2011 to 2015. These patients underwent pelvic plain radiographs and magnetic resonance imaging with T1-weighted and fat-suppressed T2-weighted fast spin echo sequences. Intravenous gadolinium was utilized. The diagnosis was verified with extirpative surgery. 16 patients with diagnosed pubic osteomyelitis from 2011 to 2015 underwent imaging at our institution. All patients demonstrated increased signal on T2- weighted sequences and decreased signal on T1-weighted sequences along the pubic symphysis and the marrow of the involved pubic rami. Inflammatory myositis with diastasis of the pubic symphysis and cortical bone erosion were identified in the majority of patients. Fluid collections were identified in 75% of patients. 63% of conventional radiographs demonstrated no radiographic evidence of pubic osteomyelitis. Magnetic resonance imaging of pubic symphysis osteomyelitis in the prostate cancer survivor is characterized by high signal on T2-weighted images and low signal on T1-weighted images of the involved pubic rami, with the majority of patients demonstrating regional myositis. Imaging data combined with clinical assessment should prompt diagnosis and management of pubic osteomyelitis. Conventional radiography is generally insensitive to these findings. We consider magnetic resonance imaging to be the definitive diagnostic modality for this clinical entity.

Circumferential wall enhancement in evolving intracranial aneurysms on magnetic resonance vessel wall imaging.

Recent MR vessel wall imaging studies have indicated intracranial aneurysms in the active state could show circumferential enhancement along the aneurysm wall (CEAW). While ruptured aneurysms frequently show CEAW, CEAW in unruptured aneurysms at the evolving state (i.e., growing or symptomatic) has not been studied in detail. The authors quantitatively assessed the degree of CEAW in evolving unruptured aneurysms by comparing it separately to that in stable unruptured and ruptured aneurysms. A quantitative analysis of CEAW was performed in 26 consecutive evolving aneurysms using MR vessel wall imaging. Three-dimensional T1-weighted fast spin echo sequences were obtained before and after contrast media injection, and the contrast ratio of the aneurysm wall against the pituitary stalk (CRstalk) was calculated as the indicator of CEAW. Aneurysm characteristics of evolving aneurysms were compared with those of 69 stable unruptured and 67 ruptured aneurysms. The CRstalk values in evolving aneurysms were significantly higher than those in stable aneurysms (0.54 vs 0.34, p < 0.0001), and lower than those in ruptured aneurysms (0.54 vs 0.83, p < 0.0002). In multivariable analysis, CRstalk remained significant when comparing evolving with stable aneurysms (odds ratio [OR] 12.23, 95% confidence interval [CI] 3.53-42.41), and with ruptured aneurysms (OR 0.083, 95% CI 0.022-0.310). The CEAW in evolving aneurysms was higher than those in stable aneurysms, and lower than those in ruptured aneurysms. The degree of CEAW may indicate the process leading to rupture of intracranial aneurysms, which can be useful additional information to determine an indication for surgical treatment of unruptured aneurysms.

Correlations of MRI manifestations with survivin gene expression in primary hepatic carcinoma.

To investigate the correlations of magnetic resonance imaging (MRI) manifestations with survivin gene expression in primary hepatocellular carcinoma (HCC). A total of 84HCC patients receiving partial hepatectomy in the Surgery Department and Oncology Department in our hospital from April 2011 to May 2014 were recruited. At 1week before operation, MRI was used to examine the imaging features of liver, a certain size of area was defined and the signal value of each sequence was recorded. HCC and para-carcinoma tissues were collected after operation, and the expression levels of survivin were detected via immunohistochemistry (IHC). All patients were followed up for 30months after operation, and the Kaplan-Meier survival curve was drawn. The correlations of survivin expression with MRI features and signal parameters of each sequence were analyzed. There was no expression of survivin in normal liver tissues. In HCC and para-carcinoma tissues, the nuclei of positive cells showed brown yellow. The positive expression rate of survivin in HCC tissues was 76.19% (64/84), which was significantly higher than that in para-carcinoma tissues (20.81%, 20/84) (p< 0.05). The overall survival (OS) of patients with high expression of survivin was 12.5months, which was significantly shorter than that of patients with low expression of survivin (17.6months) (p< 0.05). Results of chi-square test showed that the survivin level had no correlations with the MRI scan shape and edge in the tumor area (p> 0.05), but it was significantly correlated with tumor diameter, MRI enhancement features and lymphatic metastasis (p< 0.05). Pearson correlation analyses revealed that the survivin IHC score was not correlated with in-phase T1-weighted gradient-recalled echo (GRE), hepatic arterial-phase T1-weighted GRE, portal venous-phase T1-weighted GRE and equilibrium-phase T1-weighted GRE signals (p> 0.05). Besides, the survivin IHC score was negatively correlated with opposed-phase T1-weighted GRE (r=-0.46, p= 0.038), but positively correlated with T2-weighted fast spin echo signal (r=-0.49, p= 0.025). Survivin is significantly up-regulated in HCC tissues and associated with tumor growth and lymph node metastasis. Clinical detection of survivin level combined with MRI examination might be beneficial for clinical diagnosis and treatment of HCC.