MRI Unit Research Articles

28Impact of non-invasive rapid cardiac magnetic resonance for the assessment of cardiomyopathies in developing countries

Abstract Background Cardiovascular mortality is higher in developing countries. Part of that is suboptimal testing. Cardiac magnetic resonance (CMR) is the gold standard for measuring structure, function of the heart and adds incremental value by imaging scarring and to assess iron level. Despite the existence of MRI units, CMR is identified as a complex test, with poor training and availability in developing countries. Purpose To assess the potential impact of a faster CMR protocol at a multicentre level in developing countries; implementing it with an education program, for the assessment cardiomyopathies. Methods An international partnership. A rapid CMR protocol for the evaluation of cardiac volumes, function and tissue characterization (Cardiac Iron T2* and LGE for scar) Figure 1a. We deployed the protocol as a multicentre study: Argentina, Peru, India and South Africa accompanied by a program of education. Pre-scan clinical information, scanning data: complications, image quality and post-scan follow-up of participants for the assessment on impact, between 3 to 24 months. Results 510 scans (4 countries, 6 cities, 12 centres) were performed with the rapid CMR protocol. Contrast studies in 378 (74%). There were no scan-related complications. Quality of the studies was maintained in a high level as an average of 89%. 97% of studies responded referral's question. All patients with contrast CMR scan have had at least one 2D echocardiogram before CMR. Average scan duration was 21±6 mins for contrast studies and 12±3 for non-contrast T2* protocol. The most common underlying diagnoses were non-ischaemic cardiomyopathy in 73% of participants (including cardiac iron level assessment in 26%, HCM in 17%, DCM in 15%), 27% for ischaemic cardiomyopathy and 15% for other pathologies. 4 of the 12 participant centres started to incorporate CMR for the first time. Findings impacted management in 60% of patients, including new diagnosis in 21% of participants. See table 1, figure 1b. For just cardiac iron assessment: 1/3 of participants had iron deposited in the heart with 14% of patients in severe levels. Conclusions CMR can be delivered faster and easier. When this abbreviated protocol is enabled with education, it can be implemented in developing countries with existing technology. This protocol shows high quality exam, with an important impact on patient's management. Characteristics and impact on management Contrast studies Non-contrast studies All patients (%) 378 (74) 132 (36) Age, mean (range) years 54 (16–93) 24 (13–41) Male (%) 151 (39) 64 (48) Pre-echocardiography exam (%) 370 (98) 42 (32) Scanning duration mean (SD) 21 (6) 12 (3) Good quality exam (%) 329 (87) 120 (91) Impact on management Total All patients (%) 510 (100) Completely new diagnosis (%) 105 (21) Change/Addition of Medication (%) 128 (25) Intervention/ Surgery (%) 31 (6) Invasive angiography/biopsy (%) 25 (5) Hospital discharge/admission (%) 15 (3) TOTAL 306 (60%) SD: Standard Deviation. Acknowledgement/Funding Global Engagement UCL, UK Foreign & Commonwealth Office and The Peruvian Scientific, Technological Development and Technological Innovation (FONDECYT)

Fetal MRI to Assess an Aberrant Artery in Bronchopulmonary Sequestration: The Utility of a Single-Shot Turbo Spin Echo Sequence

AbstractDetecting an aberrant artery is the key to diagnosing bronchopulmonary sequestration (BPS) on fetal MRI. Few reports describe the best sequence to use for this purpose. We compared visualization of an aberrant artery in BPS on fetal MRI using single-shot turbo spin echo (SSTSE) and balanced steady state free precession (b-SSFP) sequences. We retrospectively reviewed the fetal MRI of 27 fetuses in which BPS was diagnosed prenatally (2003–2016). From these we selected 15 fetuses with the pathological diagnosis of BPS made postnatally at operation. All fetuses were examined in 1.5 T MRI units using SSTSE and b-SSFP sequences (mean gestational age: 28.4 ± 3.4 weeks). Two pediatric radiologists compared visualization of the aberrant artery using the two sequences. The presence of an aberrant artery was confirmed by postnatal contrast-enhanced CT. The influence of arterial diameter and background heterogeneity of the lung on the diagnostic power was also evaluated. All 15 fetuses clearly showed the aberrant artery on the SSTSE sequence. Conversely, the aberrant arteries detected on the SSTSE sequence were absent in the b-SSFP sequences of eight fetuses, and the other seven fetuses showed ambiguous visualization compared with the SSTSE sequence. Arterial diameter and background heterogeneity did not affect the diagnostic power in either sequence. The SSTSE sequence was superior to the b-SSFP sequence for clear visualization of the aberrant artery in BPS, regardless of the arterial diameter and background heterogeneity.

Q-Space Imaging Yields a Higher Effect Gradient to Assess Cellularity than Conventional Diffusion-weighted Imaging Methods at 3.0 T: A Pilot Study with Freshly Excised Whole-Breast Tumors.

PurposeTo determine whether q-space imaging (QSI), an advanced diffusion-weighted MRI method, provides a higher effect gradient to assess tumor cellularity than existing diffusion imaging methods, and fidelity to cellularity obtained from histologic analysis.Materials and MethodsIn this prospective study, diffusion-weighted images were acquired from 20 whole-breast tumors freshly excised from participants (age range, 35–78 years) by using a clinical 3.0-T MRI unit. Median and skewness values were extracted from the histogram distributions obtained from QSI, monoexponential model, diffusion kurtosis imaging (DKI), and stretched exponential model (SEM). The skewness from QSI and other diffusion models was compared by using paired t tests and relative effect gradient obtained from correlating skewness values.ResultsThe skewness obtained from QSI (mean, 1.34 ± 0.77 [standard deviation]) was significantly higher than the skewness from monoexponential fitting approach (mean, 1.09 ± 0.67; P = .015), SEM (mean, 1.07 ± 0.70; P = .014), and DKI (mean, 0.97 ± 0.63; P = .004). QSI yielded a higher effect gradient in skewness (percentage increase) compared with monoexponential fitting approach (0.26 of 0.74; 35.1%), SEM (0.26 of 0.74; 35.1%), and DKI (0.37 of 0.63; 58.7%). The skewness and median from QSI were significantly correlated with the skewness (ρ = −0.468; P = .038) and median (ρ = −0.513; P = .021) of cellularity from histologic analysis.ConclusionQSI yields a higher effect gradient in assessing breast tumor cellularity than existing diffusion methods, and fidelity to underlying histologic structure.Keywords: Breast, MR-Diffusion Weighted Imaging, MR-Imaging, Pathology, Tissue Characterization, Tumor ResponseOnline supplemental material is available for this article.Published under a CC BY 4.0 license.

Defective WNT signaling may protect from articular cartilage deterioration – a quantitative MRI study on subjects with a heterozygous WNT1 mutation

WNT signaling is of key importance in chondrogenesis and defective WNT signaling may contribute to the pathogenesis of osteoarthritis and other cartilage diseases. Biochemical composition of articular cartilage in patients with aberrant WNT signaling has not been studied. Our objective was to assess the knee articular cartilage in WNT1 mutation-positive individuals using a 3.0T MRI unit to measure cartilage thickness, relaxation times, and texture features. Cohort comprised mutation-positive (N=13; age 17-76 years) and mutation-negative (N=13; 16-77 years) subjects from two Finnish families with autosomal dominant WNT1 osteoporosis due to a heterozygous missense mutation c.652T>G (p.C218G) in WNT1. All subjects were imaged with a 3.0T MRI unit and assessed for cartilage thickness, T2 and T1ρ relaxation times, and T2 texture features contrast, dissimilarity and homogeneity of T2 relaxation time maps in six regions of interest (ROIs) in the tibiofemoral cartilage. All three texture features showed opposing trends with age between the groups in the medial tibiofemoral cartilage (P=0.020-0.085 for the difference of the regression coefficients), the mutation-positive individuals showing signs of cartilage preservation. No significant differences were observed in the lateral tibiofemoral cartilage. Cartilage thickness and means of T2 relaxation time did not differ between groups. Means of T1ρ relaxation time were significantly different in one ROI but the regression analysis displayed no differences. Our results show less age-related cartilage deterioration in the WNT1 mutation-positive than the mutation-negative subjects. This suggests, that the WNT1 mutation may alter cartilage turnover and even have a potential cartilage-preserving effect.

Role of Magnetic Resonance Imaging in Assessment of Anterior Cruciate Ligament Post-Grafting Cases in Terms of Graft Integrity and Complications

Background: because of the high incidence of anterior cruciate ligament (ACL) injuries among the population, these have been the subject of many recent studies. It is the most commonly reconstructed ligament in the knee. Its clinical evaluation is difficult. MRI is reliably and accurately used to assess ACL-R complications. Objective: this work is an attempt to spot light the diagnostic value of MR imaging in assessment of anterior cruciate ligament reconstruction graft for distinction of its various common complications. Patients and methods: this prospective study was conducted on 50 patients with postoperative knee reconstruction of ACL. The study was done between the duration of (April 2014 to February 2019) in an MRI unit of a private radiology center. All cases were referred from the orthopedic department of New Cairo Hospital. Results: according to our results, 33 (66%) cases showed osteoarthritic changes, suggesting that the development of osteoarthritis is one of the common complications of ACL reconstruction, however it can’t be considered the commonest complication as it can be explained by the associated risk factor as meniscal or chondral lesion. Thus osteoarthritic changes can be considered is one of the most common associated findings of ACL reconstruction and ACL reconstruction can be a risk factor for development of osteoarthritis. Conclusion: MRI of the knee is indispensable and the preferred modality in evaluating the integrity of the ACL graft and can be reliably and accurately used in diagnosing complications associated with ACL reconstruction.

Role of Magnetic Resonance Imaging in Assessment of Anterior Cruciate Ligament Post-Grafting Cases in Terms of Graft Integrity and Complications

Background: because of the high incidence of anterior cruciate ligament (ACL) injuries among the population, these have been the subject of many recent studies. It is the most commonly reconstructed ligament in the knee. Its clinical evaluation is difficult. MRI is reliably and accurately used to assess ACL-R complications. Objective: this work is an attempt to spot light the diagnostic value of MR imaging in assessment of anterior cruciate ligament reconstruction graft for distinction of its various common complications. Patients and methods: this prospective study was conducted on 50 patients with postoperative knee reconstruction of ACL. The study was done between the duration of (April 2014 to February 2019) in an MRI unit of a private radiology center. All cases were referred from the orthopedic department of New Cairo Hospital. Results: according to our results, 33 (66%) cases showed osteoarthritic changes, suggesting that the development of osteoarthritis is one of the common complications of ACL reconstruction, however it can’t be considered the commonest complication as it can be explained by the associated risk factor as meniscal or chondral lesion. Thus osteoarthritic changes can be considered is one of the most common associated findings of ACL reconstruction and ACL reconstruction can be a risk factor for development of osteoarthritis. Conclusion: MRI of the knee is indispensable and the preferred modality in evaluating the integrity of the ACL graft and can be reliably and accurately used in diagnosing complications associated with ACL reconstruction.

Congenital Cystic Lesion In Extra Hepatic Biliary Tract

Objective: To illustrate congenital cystic lesions of the extra hepatic biliary tract on the idea of information of embryologic development through the magnetic resonance cholangiopancreatography (MRCP).
 Methods: Patients that were suspected to have been suffering from biliary disease were referred to the MRI units, there the patients were narrowed done to confirm with the inclusion and exclusion cri- teria, thereafter written and informed consent was obtained from them and the procedure was ex- plained to them in detail. MRCP was performed on a 1.5 Tesla in MR unit, using phased-array coil for signal detection. Heavily T2 weighted images were obtained with SSF-SE technique. The axial sec- tions were used for pancreatic and bile ducts whereas the coronal sections were used for the pancreatobiliary tract, axial and coronal source images and reformatted images were evaluated to- gether for the possibility of any anomaly in extra hepatic biliary tract. This was an observational, cross sectional, prospective study with a sample size of 377 patients. Statistical analysis was done by SPSS version 16.
 Results: Choledochal cyst was found in 11 of the 377 patients with a gender separate frequency of 6 out of 196 females and 5 out of 181 males, with a total frequency of 2.9% and a p-value at <0.001 which was significant.
 Conclusion: By identifying the inherent anomalies that present themselves during the visualization of the biliary tract through MRCP and MRI, while coupled with information regarding the clinical signifi- cance of every entity, is vital for establishing an accurate diagnosis and in guiding acceptable clinical intervention and management.

The interventional magnetic resonance imaging suite: Experience in the design, development, and implementation in a pre-existing radiology space and review of concepts.

Background:Intraoperative magnetic resonance imaging (ioMRI) has led to significant advancements in neurosurgery with improved accuracy, assessment of the extent of resection, less invasive surgical alternatives, and real-time confirmation of targeting as well delivery of therapies. The costs associated with developing ioMRI units in the surgical suite have been obstacles to the expansion of their use. More recently, the development of hybrid interventional MRI (iMRI) units has become a viable alternative. The process of designing, developing, and implementing operations for these units requires the careful integration of environmental, technical, and safety elements of both surgical and MR practices. There is a paucity of published literature providing guidance for institutions looking to develop a hybrid iMRI unit, especially with a limited footprint in the radiology department.Methods:The experience of designing, developing, and implementing an iMRI in a preexisting space for neurosurgical procedures at a single institution in light of available options and the literature is described.Results:The development of the unit was accomplished through the engagement of a multidisciplinary team of stakeholders who utilized existing guidelines and recommendations and their own professional experience to address issues including physical layout, equipment selection, operations planning, infection control, and oversight/review, among others.Conclusion:Successful creation of an iMRI program requires multidisciplinary collaboration in integrating surgical and MR practice. The authors’ aim is that the experience described in this article will serve as an example for facilities or neurosurgical departments looking to navigate the same process.

National audit on the appropriateness of CT and MRI examinations in Luxembourg

ObjectivesIn Luxembourg, the frequency of CT and MRI examinations per inhabitant is among the highest in Europe. A national audit was conducted to evaluate the appropriateness of CT and MRI examinations according to the national referral guidelines for medical imaging.MethodsThree hundred and eighty-eight CT and 330 MRI requests corresponding to already performed examinations were provided by all radiology departments in Luxembourg. Four external radiologists evaluated the clinical elements for justification present in each request. They consensually assessed the appropriateness of each requested examination with regard to the national referral guidelines and their clinical experience.ResultsThe appropriateness rate (AR) was higher for MRI requests than for CT requests (79% vs. 61%; p < 0.001). AR was higher for requests referred by medical specialists rather than by general practitioners, both for CT requests (70% vs. 37%; p < 0.001) and MRI requests (83% vs. 64%; p = 0.002). For CT, AR was higher when the requests concerned paediatric rather than adult patients (82% vs. 58%; p < 0.001), when the radiology departments were equipped with both CT and MRI units rather than with only CT units (65% vs. 47%, p = 0.004) and when the requests concerned head-neck (79%), chest (77%) and chest-abdominal-pelvic (81%) areas rather than spinal (28%), extremity (51%) and abdominal-pelvic (63%) areas (p < 0.001).ConclusionsThe appropriateness of CT and MRI in Luxembourg is not satisfactory and collective efforts to improve should be continued. The focus should be on general practitioners and on spinal CT examinations.

A preliminary ergonomic analysis of the MRI work system environment: Implications and recommendations for safety and design

IntroductionThe MRI work system environment in acute hospitals poses a significant risk of harm to patients, healthcare practitioners and others, but knowledge of hazards and potential design improvements are limited as safety research is lacking. The aim of this exploratory study was to understand how the discipline of Human Factors and Ergonomics (HFE) can support the understanding and improvement of safety and performance of MRI working environments. MethodsA multi-method study of two MRI units in Scottish acute hospital settings based on Human Factors and Ergonomics (HFE) principles was undertaken in May 2016. Data collection sources included published literature, local and national safety incident data, site observations and staff interviews which were triangulated and subject to a content analysis. ResultsA diverse range of system-wide hazards were highlighted which impact on the complexity of MRI work, patient and staff safety and system performance (e.g. adequacy of training and procedures, interactions with equipment, organisation of work). Preliminary recommendations were made to improve system design related to national approaches to safety (e.g. equipment procurement; staff training and procedural standards); interaction design and standardisation (e.g. physical design and barriers, staff uniforms, checking processes); and introduction of MRI passports for patients. ConclusionsThis exploratory study suggests the need for national co-ordination and standardisation of MRI safety management strategies, based on safety science and HFE evidence and approaches to improve system design and reduce risk to patients, staff and others. A series of provisional recommendations are offered for consideration.

Abnormal functional network centrality in drug-naïve boys with attention-deficit/hyperactivity disorder.

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed neurodevelopmental disorder in childhood and is characterized by inattention, impulsivity, and hyperactivity. Observations of distributed functional abnormalities in ADHD suggest aberrant large-scale brain network connectivity. However, few studies have measured the voxel-wise network centrality of boys with ADHD, which captures the functional relationships of a given voxel within the entire connectivity matrix of the brain. Here, to examine the network patterns characterizing children with ADHD, we recruited 47 boys with ADHD and 21 matched control boys who underwent resting-state functional imaging scanning in a 3.0 T MRI unit. We measured voxel-wise network centrality, indexing local functional relationships across the entire brain connectome, termed degree centrality (DC). Then, we chose the brain regions with altered DC as seeds to examine the remote functional connectivity (FC) of brain regions. We found that boys with ADHD exhibited (1) decreased centrality in the left superior temporal gyrus (STG) and increased centrality in the left superior occipital lobe (SOL) and right inferior parietal lobe(IPL); (2) decreased FC between the STG and the putamen and thalamus, which belong to the cognitive cortico-striatal-thalamic-cortical (CSTC) loop, and increased FC between the STG and medial/superior frontal gyrus within the affective CSTC loop; and (3) decreased connectivity between the SOL and cuneus within the dorsal attention network. Our results demonstrated that patients with ADHD show a connectivity-based pathophysiological process in the cognitive and affective CSTC loops and attention network.

Accuracy of detecting enlargement of aneurysms using different MRI modalities and measurement protocols.

Aneurysm growth is considered predictive of future rupture of intracranial aneurysms. However, how accurately neuroradiologists can reliably detect incremental aneurysm growth using clinical MRI is still unknown. The purpose of this study was to assess the agreement rate of detecting aneurysm enlargement employing generally used MRI modalities. Three silicone flow phantom models, each with 8 aneurysms of various sizes at different sites, were used in this study. The aneurysm models were identical except for an incremental increase in the sizes of the 8 aneurysms, which ranged from 0.4 mm to 2 mm. The phantoms were imaged on 1.5-T and 3-T MRI units with both time-of-flight (TOF) and contrast-enhanced MR angiography. Three independent expert neuroradiologists measured the aneurysms in a blinded manner using different measurement approaches. The individual and agreement detection rates of aneurysm enlargement among the 3 experts were calculated. The mean detection rate of any increase in any aneurysmal dimension was 95.7%. The detection rates of the 3 observers (observers A, B, and C) were 98.0%, 96.6%, and 92.7%, respectively (p = 0.22). The detection rates of each MRI modality were 91.3% using 1.5-T TOF, 97.2% using 1.5-T with Gd, 95.8% using 3.0-T TOF, and 97.2% using 3.0-T with Gd (p = 0.31). On the other hand, the mean detection rate for aneurysm enlargement was 54.8%. Specifically, the detection rates of observers A, B, and C were 49.0%, 46.1%, and 66.7%, respectively (p = 0.009). As the incremental enlargement value increased, the detection rate for aneurysm enlargement increased. The use of 1.5-T Gd improved the detection rate for small incremental enlargement (e.g., 0.4–1 mm) of the aneurysm (p = 0.04). The location of the aneurysm also affected the detection rate for aneurysm enlargement (p < 0.0001). The detection rate and interobserver agreement were very high for aneurysm enlargement of 0.4–2 mm. The detection rate for at least 1 increase in any aneurysm dimension did not depend on the choice of MRI modality or measurement protocol. Use of Gd improved the accuracy of measurement. Aneurysm location may influence the accuracy of detecting enlargement.

Efficacy of diffusion tensor imaging in identification of degenerative cervical spondylotic myelopathy

Aim and objectivesTo study the diagnostic accuracy of Diffusion tensor imaging technique in detection of cervical spondylotic myelopathy changes. Material and methodStudy population included 50 patients with symptoms of cervical myelopathy. The patients were evaluated based on symptoms using the European myelopathy scoring system and were divided into: Grade 1, including patients with mild symptoms; Grade 2, referring to patients with moderate symptoms and Grade 3, which included patients revealing severe symptoms. All the patients were investigated with a 1.5 T MRI unit acquiring DWI and DTI sequences. FA and ADC values from each spinal segment were analyzed in terms of Frequency, Percentage, Mean, Standard Deviation and Confidence Intervals. The comparison of values was done by ANOVA and post hoc analysis by bonferroni test. Comparison of accuracy of FA, ADC and T2WI in recognizing myelopathic changes was done by t-test. Receiver Operating Characteristics (ROC) analysis was performed to obtain a cut off value of FA and ADC for each spinal level to identify myelopathic change in the spinal cord. ResultsThe study revealed a significant difference in the mean FA and ADC value of stenotic and Non-stenotic segments. T2WI was highly significant (p = 0.000) in recognizing myelopathy changes in patients falling under Grade 2(moderate) and Grade 3(severe) according to European Myelopathy scoring system. Regarding patients under Grade 1 (mild) FA and ADC values showed significant difference compared to T2WI. The collective sensitivity in the identification of myelopathic changes was highest with FA (79%) as compared to ADC (71%) and T2WI (50%). ROC analysis was done to determine the cut off values of FA and ADC at each cervical spine segments. The proposed cut off, for FA and ADC at the level of C1–C2 is 0.68 and 0.92, C2–C3 is 0.65 and 1.03, C3–C4 is 0.63 and 1.01, C4–C5 0.61 and 0.98, At C5–C6 0.57 and 1.04, At C6–C7 0.56 and 0.96 respectively. ConclusionFA and ADC values enhance the efficacy and accuracy of MRI in the diagnosis of cervical spondylotic myelopathy. Hence diffusion tensor imaging can be used as a non-invasive modality to recognize spondylotic myelopathy changes even in the early stages, which can be helpful in deciding on appropriate timing of decompression surgery before the irreversible chronic changes set in.

Radiomics of Brain MRI: Utility in Prediction of Metastatic Tumor Type.

Purpose To investigate the feasibility of tumor type prediction with MRI radiomic image features of different brain metastases in a multiclass machine learning approach for patients with unknown primary lesion at the time of diagnosis. Materials and methods This single-center retrospective analysis included radiomic features of 658 brain metastases from T1-weighted contrast material-enhanced, T1-weighted nonenhanced, and fluid-attenuated inversion recovery (FLAIR) images in 189 patients (101 women, 88 men; mean age, 61 years; age range, 32-85 years). Images were acquired over a 9-year period (from September 2007 through December 2016) with different MRI units, reflecting heterogeneous image data. Included metastases originated from breast cancer (n = 143), small cell lung cancer (n = 151), non-small cell lung cancer (n = 225), gastrointestinal cancer (n = 50), and melanoma (n = 89). A total of 1423 quantitative image features and basic clinical data were evaluated by using random forest machine learning algorithms. Validation was performed with model-external fivefold cross validation. Comparative analysis of 10 randomly drawn cross-validation sets verified the stability of the results. The classifier performance was compared with predictions from a respective conventional reading by two radiologists. Results Areas under the receiver operating characteristic curve of the five-class problem ranged between 0.64 (for non-small cell lung cancer) and 0.82 (for melanoma); all P values were less than .01. Prediction performance of the classifier was superior to the radiologists' readings. Highest differences were observed for melanoma, with a 17-percentage-point gain in sensitivity compared with the sensitivity of both readers; P values were less than .02. Conclusion Quantitative features of routine brain MR images used in a machine learning classifier provided high discriminatory accuracy in predicting the tumor type of brain metastases. © RSNA, 2018 Online supplemental material is available for this article.

246. Analysis of signal-to-noise ratio for a 2-channels coil developed to enable transcranial Magnetic Resonance-guided Focused Ultrasound Surgery (tcMRgFUS) with 1.5 T MRI scanners

PurposeIn recent years trans-cranial Magnetic Resonance-guided Focused Ultrasound Surgery (tcMRgFUS) treatments have aroused large scientific and medical interest [1]. Usually, tcMRgFUS systems are integrated with 3 T systems which allow the use of the body RF coil for both real time imaging and MR-thermometry. At University Hospital of Palermo there is the world-first installation of a tcMRgFUS system integrated with a 1.5 T scanner. Here we present the characterization in terms of signal-to-noise ratio (SNR) of a dedicated RF coils suitably developed (by InSightec) to enable tcMRgFUS treatments with 1.5 T MR units. Methods and materialsThe focused ultrasound equipment (ExAblate 4000, InSightec) integrates with an MRI unit operating at 1.5 T (Signa HDxt, GE) and consists of a hemispheric 1024-element phased-array transducer. T2w-FRFSE images were obtained from a dedicated Dose Quality Assurance phantom using the same MRI protocol used for real treatments. ResultsThe dedicated flexible coil resulted in larger SNR values with respect to that achieved using MRI’s body RF coil. In particular, we obtained for the axial plane a SNR equal to 27.5 using dedicated coil whereas it was equal to 2.5 with RF body coil (SNR gain more than 10 times higher). ConclusionWe can conclude that, even though the SNR linearly increases with magnetic field strength, the use of a dedicated coil on a 1.5 T scanner enabled us to obtain images with a SNR roughly 5 times larger than those acquired on 3T scanners using MRI’s body RF coil. This could facilitate the spread of this cutting-edge technology worldwide [2].

Usefulness of both PET/CT with F18-FDG and whole-body diffusion-weighted imaging in cancer screening: a preliminary report.

Positron emission tomography/computed tomography (PET/CT) with fluorodeoxyglucose (F18-FDG) is useful for the detection of malignant lesions, including metastatic lesions, and this technique is widely used in cancer screening. However, this approach may occasionally yield false-positive and false-negative findings. At our PET center, to increase the accuracy of PET/CT, we use PET/CT and whole-body diffusion-weighted imaging (WB-DWI) together. This study aimed to assess the usefulness of this combination. We examined 29 subjects with confirmed diagnosis. All of them had undergone PET/CT and WB-DWI on the same day. Twenty-seven of them also underwent ultrasonography, blood testing, and upper gastrointestinal series on the same day and two fecal occult blood tests on another day. WB-DWI was performed on a 1.5-T MRI unit with a b value of 0 and 800 or 1000s/mm2. For all 29 cases, PET/CT and WB-DWI were classified to be positive or negative, and the diagnostic ability was calculated for each modality. Among the 29 subjects, 17 had malignant tumors and 12 had benign tumors or no abnormalities. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET/CT were 65%, 25%, 55%, 33%, and 48%, respectively; while the corresponding values for WB-DWI were 59%, 100%, 100%, 63%, and 76%, respectively. By considering the result to be negative when PET/CT findings were positive but WB-DWI findings were negative, specificity increased from 25 to 100%, and accuracy increased from 48 to 76%. On the other hand, by considering the result to be positive when the findings of either PET/CT or WB-DWI were positive, sensitivity increased from 65 to 76%, and accuracy increased from 48 to 55%. Our results suggest that using both PET/CT and WB-DWI together can increase accuracy in cancer screening. However, this approach was not able to detect malignant lesions in some cases, indicating that there were limitations with imaging certain organs. Therefore, it is important to further understand the features of PET/CT and WB-DWI and use them appropriately for each organ. Additionally, given that the study sample was relatively small, further research is needed to validate these findings.

Role of Multi-Slice Computed Tomography and Magnetic Resonance Imaging in Evaluation of Laryngeal Tumors

AbstractBackground: Imaging of laryngeal tumors is crucial for evaluation, preparing, treatment and for ensuring proper follow-up. Computed tomography and magnetic resonance imaging are the main imaging tools. Each modality showed its own advantages for assessment of local, regional or distant staging.Aim of Study: The aim of this study was to evaluate the role of multi slice computed tomography and magnetic reso-nance imaging in diagnosis of laryngeal tumors.Material and Methods: This prospective study included (30) patients in different age groups who were highly suspected with laryngeal tumors or known to be having laryngeal tumor. Patients were referred by Oto Rhino Laryngology (ORL) Department of Tanta University Hospital to the CT Unit & MRI Units of the Diagnostic Radiology & Medical Imaging Department, Tanta University Hospitals. All cases were sub-jected to full history, complete physical examination, radio-logical & medical imaging examination at which all cases were exposed to CT scanning of the neck while only 22 cases of them performed additional MRI examination of the neck. Further endoscopic examination and histopathological corre-lation were done. Data was analyzed by using SPSS.Results: MRI showed higher accuracy than CT as regards to pathological T staging of laryngeal tumors 244 that showed 86.4% for MRI while 66.7% for CT. Both CT and MRI were equal in evaluation of certain areas as anterior commissure and pyriform sinus while MRI showed higher accuracy in evaluation of other laryngeal subsites namely preepiglottic, paraglottic spaces, posterior commissure, epiglottis, vocal cords, thyroid cartilage extralaryngeal spread.and metastatic lymphadenopathy with the total accuracy higher in MRI than in CT.Conclusion: MRI could be considered a helpful diagnostic method for pre and post-therapeutic staging of laryngeal tumors specially early glottic lesions and the combined utility of CT and MRI could help to overcome the disadvantages and improve the accuracy specially about thyroid cartilage assessment and T staging of laryngeal carcinomas.

Accurate estimation of diffusion kurtosis (DK) imaging parameters of the prostate

Purpose: To evaluate the performance of maximum likelihood (ML) estimation of diffusion kurtosis (DK) imaging parameters in the prostate and compare the estimated parameters to those measured using least squares (LS) estimation. Materials and methods: The institutional review board issued a waiver of informed consent for this Health Insurance Portability and Accountability Act (HIPAA)-compliant, retrospective study of forty-two patients (median [Md] age=61 years; range: 43-74 years) who underwent magnetic resonance imaging (MRI) between September and October 2016. Diffusion-weighted MRI (DW-MRI) at nine b-values (0-2000 s/mm2 ) were acquired using a 3-T whole-body MRI unit (Discovery MR750; GE Medical Systems, Waukesha, WI) equipped with an eight-channel phased array coil for signal reception. Diffusion coefficient (D) and kurtosis (K) were estimated from the normal appearing prostate peripheral zone and prostate cancer regions of interest (ROIs). The parameters were estimated by fitting the measured MR signal intensities as a function of b-value, using LS and ML algorithms. An estimate of the noise was obtained on the b=0 images in an artifact-free ROI in the rectum. Simulations were also carried out to assess the properties of the two estimators in a range of signal-to-noise ratios. Results: For benign ROIs, the mean D ± standard deviation, (1.88±0.52)×10-3 mm2 /sec, and mean K (0.79±0.20), measured using LS estimation, differed significantly from the mean D (1.96±0.48)×10-3 mm2 /sec and mean K (0.68±0.21), measured using ML estimation (P&lt;0.001 for both). For malignant ROIs, the mean D (1.48±0.38)×10-3 mm2 /sec and mean K (0.94±0.20), measured using LS estimation, differed significantly from the mean D (1.54±0.36)×10-3 mm2 /sec and mean K (0.81±0.19), measured using ML estimation (P&lt;0.001 for both). Simulations demonstrate that ML minimizes the bias estimate of DK parameters within the signal-to-noise ratio range of 5-15. Conclusion: By incorporating the noise level, the ML estimation increases the accuracy of DK parameter estimation. In vivo results with phased array coils showed significant differences in DK parameter estimates with ML as compared with the standard LS estimation.

Mutiparametric Magnetic Resonance Imaging in Assessing Ovarian Cysts

Objective: Is to study the role of multi-parametric MRI including the novel sequences, diffusion weighted images (DWI) in the characterization of ovarian cystic lesions. Methodology: This study carried out in MRI unit, Radiology Department of Ain Shams University Hospitals. 20 patients with pathologically proven nature of ovarian cyst underwent pelvic MRI examination including diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) Result: Diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) to detect nature of ovarian cysts can’t be carried alone but need to be combined by conventional and DCE MRI.

Mutiparametric Magnetic Resonance Imaging in Assessing Ovarian Cysts

Objective: Is to study the role of multi-parametric MRI including the novel sequences, diffusion weighted images (DWI) in the characterization of ovarian cystic lesions. Methodology: This study carried out in MRI unit, Radiology Department of Ain Shams University Hospitals. 20 patients with pathologically proven nature of ovarian cyst underwent pelvic MRI examination including diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) Result: Diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) to detect nature of ovarian cysts can’t be carried alone but need to be combined by conventional and DCE MRI.