Phased-array Coil Research Articles

Exploration of the correlation between superficial cerebral veins identified using susceptibility-weighted imaging findings and cognitive differences between sexes based on deep learning: a preliminary study.

This study aimed to investigate the association of superficial cerebral veins (SCVs) with sex-related cognitive differences and the possible hemodynamic mechanisms underlying these associations. This investigation was a prospective case-control study. A total of 344 healthy volunteers were recruited. In all, 200 volunteers were included to establish the deep learning model, and 144 volunteers were used for the research, including 72 males (50%) and 72 females (50%). No significant differences in age (P=0.358) or education (P=0.779) were observed between the sexes. Cognitive functioning was evaluated using neuropsychological tests, including the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment-Basic (MOCA-B). Susceptibility-weighted imaging scans were acquired with a 3.0 T magnetic resonance imaging system using a 32-channel high-resolution phased array coil. Minimum intensity projection images were obtained by reconstructing susceptibility-weighted imaging data. A deep learning model was trained on the minimum intensity projection images to quantify the diameter, tortuosity index, length, and the number of SCVs in the bilateral cerebral hemispheres. Finally, the association between cognitive differences between males and females and the properties of the SCVs was analyzed. The MMSE and MOCA-B scores of males were significantly higher than those of females (P<0.05). Males had more SCVs in the bilateral cerebral hemispheres than did females (right hemisphere: P<0.01; left hemisphere: P<0.05). The number of SCVs in the right cerebral hemisphere was significantly and positively correlated with the MMSE and MOCA-B scores (correlation coefficients: 0.246 and 0.201, respectively; P<0.05). The number of SCVs in the left cerebral hemisphere was positively correlated with the MMSE scores (correlation coefficient: 0.196; P<0.05) and the MOCA-B scores. In this study, no significant correlations were observed between cognition and the diameter, length, or tortuosity index of the SCVs in the bilateral cerebral hemispheres. The cognitive function of males was better than that of females, and the different numbers of SCVs may be one of the explanations for this phenomenon of sex-based differences in cognition.

Magnetic Resonance Imaging in Traumatic Brachial Plexus Injuries: A 6-Year Experience.

Background and Purpose: There is limited information in the literature on epidemiology of high-energy brachial plexus injuries evaluated with MR neurography (MRN). The aim of the present study is to describe the demographic characteristics of brachial plexus injuries secondary to motorcycle accident patients in the city of Fortaleza-Ceara, Brazil, and analyze the association of those data with the features of the brachial plexus lesions observed on MRN findings. Materials and Methods: A review of sixty medical charts and MRN findings of victims of motor vehicle accidents (MVA) in northeast, from November 2011 to November 2017. Demographic and imaging data collected included age, sex, laterality and level of the lesion and time interval between trauma and MRN examination. The MRN examinations were carried out on a GE 1.5T MR unit (Signa HDxT- General Electric, Milwaukee, USA) or on a Phillips 3T MR unit (Philips Achieva X-series - Philips Medical Systems, Best, The Netherlands). Dedicated multichannel phased-array coils. Results: The longest time interval from trauma to imaging was 330 days and between trauma and surgery was 692 days. Preganglionic lesions (avulsion) predominated, consisting of 52 patients (86.6%) reflecting the high energy trauma with upper limb traction from the neck. The lesions were most prevalent at the C6-C8 levels. Pseudomeningocele was identified in 62.9% of the preganglionic lesions and in only 1.6% of the postganglionic lesions. Regional muscle denervation changes were seen in all pre-ganglionic injuries and most of post-ganglionic injuries. Conclusions: MRN of the brachial plexus provides important insights into the distribution of neuromuscular lesions in high energy MVA trauma and these findings enrich the literature for researchers and clinicians focused on managing such patients and/or defining prognostic strategies.

Diagnostic performance of magnetic resonance imaging in preoperative local staging of rectal cancer after neoadjuvant chemoradiotherapy

This paper aims to investigate the diagnostic performance of magnetic resonance imaging (MRI) in predicting the pathologic stage of locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (CRT) and the role of MRI in selecting patients with a pathologic complete response (ypCR). Restaging MRI (yMRI) examinations of 136 patients with LARC treated with neoadjuvant CRT followed by surgery were retrospectively analyzed by two radiologists. All examinations were performed on a 1.5 Tesla MRI machine with a pelvic phased-array coil. T2-weighted turbo spin-echo images and diffusion-weighted imaging were obtained. Histopathologic reports of the surgical specimens were the reference standard. The accuracy, sensitivity, specificity, positive and negative predictive values (PPV and NPV) of yMRI in predicting the pathologic T-stage (ypT), N-stage, and ypCR were calculated. The inter-observer agreement was evaluated using kappa statistics. The yMRI results showed 67% accuracy, 59% sensitivity, 80% specificity, 81% PPV, and 56% NPV in identifying ypT (ypT0-2 versus ypT3-4). In predicting the nodal status, the yMRI results revealed 63% accuracy, 60% sensitivity, 65% specificity, 47% PPV, and 75% NPV. In predicting ypCR, the yMRI results showed 84% accuracy, 20% sensitivity, 92% specificity, 23% PPV, and 90% NPV. The kappa statistics revealed substantial agreement between the two radiologists. Utilization of yMRI showed high specificity and PPV in predicting the tumor stage and high NPV in predicting the nodal stage; in addition, yMRI revealed moderate accuracy in the T and N classifications, mainly due to underestimating the tumor stage and overestimating the nodal status. Finally, yMRI revealed high specificity and NPV but low sensitivity in predicting the complete response.

Diagnostic Accuracy of Magnetic Resonance Cholangiopancreatography in Comparison With Endoscopic Retrograde Cholangiopancreatography for Detection of the Etiology of Obstructive Jaundice.

Despite technological advances, obstructive jaundice has significant morbidity and mortality rates. When studying obstructive jaundice, endoscopic retrograde cholangiopancreatography (ERCP), the "gold standard" for biliary obstruction identification, might be replaced with magnetic resonance cholangiopancreatography (MRCP), which is a non-invasive procedure. Diagnostic accuracy of MRCP in comparison with ERCP for the detection of the etiology of obstructive jaundice. This prospective, observational study included 102 patients who presented with obstructive jaundice as proven by liver function tests. The MRCP was conducted within 24 to 72 hours before the ERCP. A torso phased-array coil (Siemens, Germany) was used for the MRCP. The duodeno-videoscope and general electric fluoroscopy were used to perform the ERCP. The MRCP was evaluated by a classified radiologist who was blinded to the clinical details. An experienced consultant gastroenterologist who was blinded to the results of the MRCP assessed the cholangiogram of each patient. The hepato-pancreaticobiliary system results from both procedures were compared based on the pathology observed, such as choledocholithiasis, pancreaticobiliary strictures, and dilatation of biliary strictures. We determined the sensitivity, specificity, and negative and positive predictive values with 95% confidence intervals. The statistical significance was set at p<0.05. The most commonly reported pathology was choledocholithiasis, and MRCP diagnosed 55 patients, of which 53 were true positive cases when compared with the ERCP results of the same patients. MRCP demonstrated greater sensitivity and specificity (respectively) for screening choledocholithiasis (96.2, 91.8), cholelithiasis (100, 75.8), pancreatic duct stricture (100, 100), and hepatic duct mass (100, 100) and showed statistically significant values. The sensitivity of MRCP is lower for identifying benign and malignant strictures, but its specificity was observed to be reliable. When it comes to determining the severity of obstructive jaundice, both in its early and later stages, the MRCP technique is widely regarded as a reliable means of diagnostic imaging. The diagnostic function of ERCP has been significantly reduced as a result of the precision of MRCP as well as its non-invasive nature. In addition to being a helpful non-invasive method to identify biliary diseases and avoid unnecessary ERCPs and their risks, MRCP offers good diagnostic accuracy for obstructive jaundice.

Clinical Utility of Arterial Spin Labeling Magnetic Resonance Imaging in the Evaluation of the Brain.

Cerebral blood flow (CBF) is essential for studying the brain in both normal and diseased states. Arterial spin labeling (ASL) is a functional magnetic resonance imaging (MRI) technique that uses arterial water as an endogenous tracer to measure CBF, thus does not require an injection of exogenous tracers and is noninvasive and can therefore be used to track changes in CBF. This prospective, observational and descriptive study was done at the department of imaging, Maxcure Hospital, Hyderabad, for the duration of 18 months. All studies were performed on a 1.5T Philips Prodiva CX using a phased array coil. A prospective observational and descriptive study was done among 100 patients to study the clinical utility of ASL. Out of 100 patients, 20 (20%) patients showed normal MRI findings. Rest 80 (80%) patients had abnormal MRI findings. ASL provides additional and complementary information to that available from structural MRI in all categories of abnormalities.

Diagnostic Accuracy of Magnetic Resonance Imaging in Detection of Perianal Fistula keeping Surgical Findings as Gold Standard

An abnormal connection between the rectum or canal and the anal skin is called as a perianal fistula (PAF). MRI is considered as a gold standard for the imaging of PAF because of its operator dependence, non-invasive nature, excellent soft tissue contrast, superior field of view and multiplanar capabilities. Objective: To assess the validity of magnetic resonance imaging in detecting perianal fistulas while using surgical findings as the gold standard. Methods: From 1 January 2021 to 30 January 2022, a cross-validation research was carried out in the radiology department at Memon Medical Institute Hospital in Karachi, Pakistan. The research comprised 153 individuals with PAF ranging in age from 18 to 70 years and of either gender. A 1.5 T MR scanner was used to obtain the MRI. All techniques used a phased-array coil for image capture in all circumstances. The imaging volume encompassed the distal rectum, anal canal, and subcutaneous tissues. Fat saturation pictures were taken in the oblique, axial, and coronal planes. A radiologist examined images, and pertinent patient data were noted on a pre-drafted proforma. Histopathological and post-surgical results were acquired and documented. Results: The validity of MRI for the diagnosis of PAF was 82.4% by taking surgical findings as gold standard. Conclusion: For the assessment of PAF and the detection of abscesses, MRI is a beneficial and reliable preoperative examination

Radiofrequency Coils for Low-Field (0.18–0.55 T) Magnetic Resonance Scanners: Experience from a Research Lab–Manufacturing Companies Cooperation

Low-field magnetic resonance imaging (MRI) has become increasingly popular due to cost reduction, artifact minimization, use for interventional radiology, and a better safety profile. The different applications of low-field systems are particularly wide (muscle–skeletal, cardiac, neuro, small animals, food science, as a hybrid scanner for hyperthermia, in interventional radiology and in radiotherapy). The low-field scanners produce lower signal-to-noise ratio (SNR) images with respect to medium- and high-field scanners. Thus, particular attention must be paid in the minimization of the radiofrequency (RF) coil losses compared to the sample noise. Following a short description of the coil design and simulation methods (magnetostatic and full-wave), in this paper we will describe how the choice of electrical parameters (such as conductor geometry and capacitor quality) affects the coil’s overall performance in terms of the quality factor Q, ratio between unloaded and loaded Q, and coil sensitivity. Subsequently, we will summarize the work carried out at our electromagnetic laboratory in collaboration with MR-manufacturing companies in the field of RF coil design, building, and testing for 0.18–0.55 T magnetic resonance (MR) clinical scanners by classifying them between surface-, volume-, and phased-array coils.

The confound of head position in within-session connectome fingerprinting in infants

Individuals differ in their functional connectome, which can be demonstrated using a “fingerprinting” analysis in which the connectome from an individual in one dataset is used to identify the same person from an independent dataset. Recently, the origin of these fingerprints has been studied by examining if they are present in infants. The results have varied considerably, with identification rates from 10 to 90%. When fingerprinting has been performed by splitting a single imaging session into two split-sessions (within session), identification rates were higher than when two full-sessions (between sessions) were compared. This study examined whether a methodological difference could account for this variation. It was hypothesized that the infant's exact head position in the head coil may affect the measured connectome, due to the gradual inhomogeneity of signal-to-noise in phased-array coils and the breadth of possible positions for a small infant head in a head coil. This study examined the impact of this using resting state functional MRI data from the Developing Human Connectome Project second release. Using functional timeseries, fingerprinting identification was high (84-91%) within a session while between sessions it was low (7%).Using N = 416 infants’ head positions, a map of the average signal-to-noise across the physical volume of the head coil was calculated and was used (independent group of 44 infants with two scan sessions) to demonstrate a significant relationship between head position in the head coil and functional connectivity. Using only the head positions (signal-to-noise values extrapolated from the group average map) of the independent group of 44 infants, high identification success was achieved across split-sessions (within session) but not full-sessions (between sessions). Using a model examining factors influencing the stability of the functional connectome, head position was seen as the strongest of the explanatory variables. We conclude within-session fingerprinting is affected by head position and future infant functional fingerprint analyses must use a different strategy or account for this impact.

Tumor Volume Predicts for Baseline Hypoxia Status in HPV Related Oropharyngeal Carcinomas (OPC) that Underwent Major Radiation De-escalation: The 30 Reduction in Oropharyngeal Cancer Trial

<h3>Purpose/Objective(s)</h3> The 30 ROC Trial utilizes functional imaging, specifically pre-treatment (Tx) and intra-Tx fluorine-18-labeled fluoromisonidazole positron emission tomography (18F-FMISO PET) to select appropriate human papillomavirus positive (HPV+) OPC patients for major de-escalation to 30 Gy. In this trial, patients also underwent pre-Tx and weekly multiparametric magnetic resonance imaging (MRI) scans to correlate with hypoxia status. The aim of the present study was to assess the value of MRI tumor volume to predict baseline hypoxia status in HPV+OPC patients who underwent major dose de-escalation. <h3>Materials/Methods</h3> A total (N = 158) patients with cT0-2,N1-2b (AJCC 7^th ed.) p16+ OPC were enrolled. All patients had pre-Tx 18F-FMISO PET scans to assess baseline hypoxia status, and only those with baseline hypoxia underwent a repeat intra-Tx scan. Pre-Tx and weekly intra-Tx MRI scans were acquired on technology company's 3T MRI scanner using a neurovascular phased array coil. Radiation oncologists delineated gross nodal disease as regions of interest on T₂w images. Tumor volume (cm³) was calculated in ITK SNAP for each patient using the segmentation software. All standard statistical analyses were performed on RStudio 2021.09.2. <h3>Results</h3> Of the 158 patients, N=95 patients had analyzable pre-Tx and weekly on-Tx MRI scans. Based on pre-Tx 18F-FMISO PET results, increased tumor volume was associated with baseline nodal hypoxia (N=69, median 18.55 cm³, range: 3.15- 60.62) compared to initially non-hypoxic tumors (N= 26, median 6.44 cm³, range: 0.48 – 47.74, p<0.001). After the intra-Tx 18F-FMISO PET result, patients were further stratified into converted negative (N= 57), persistently hypoxic (N=12), and never hypoxic (N=26). We found that the median pre-Tx nodal volume for the persistently hypoxic (median 17.75 cm³, range 5.54- 42.93, p=0.006) and converted negative (median 18.55 cm³, range 3.15 – 60.62, p<0.001) groups was significantly (P= <0.05) increased compared to the initially hypoxia negative patients (6.44 cm³, range 0.48 – 47.74). We performed further assessment of this pattern with intra-Tx MRIs (weeks 1-4) and found that this correlation of groups with baseline hypoxia (converted negative and persistently hypoxic) continued to exhibit larger nodal volume compared to the never hypoxic group. <h3>Conclusion</h3> Pre-Tx nodal volume on MRI correlates with pre-Tx hypoxia status where the larger the volume, the higher the likelihood of hypoxia. This correlation continued throughout radiation Tx as evidenced by the weekly MRI scans.

Prospective Assessment of Diffusion-Weighted-MRI as a Biomarker of Treatment Response and Disease Control in Head and Neck Cancer

<h3>Purpose/Objective(s)</h3> To determine diffusion-weighted MRI (DWI) parameters associated with tumor response and local control (LC) in head and neck (HNC) patients treated with definitive radiation therapy (RT). <h3>Materials/Methods</h3> Eighty-seven HNC patients enrolled in an active prospective imaging study at MD Anderson Cancer Center were included in the analysis. Patients had MRIs prior to, at mid-RT, and post-treatment completion. Inclusion criteria include adult with histologic evidence of malignant head and neck neoplasm indicated for curative-intent treatment with RT with/without chemotherapy; good performance status (ECOG score 0-2); and with no contraindications to MRI. Patients were scanned using a full-body MRI scanner with two large four-channel flex phased-array coils. We used fat-suppressed T2-weighted turbo spin echo for tumor segmentation which was co-registered to respective DWIs for extraction of apparent diffusion coefficient (ADC) measurements. Sequence parameters were (TR/TE (ms); pixel size/slice thickness (mm); b-values (s/mm2)): T2-weighted (5280/80; 0.5/2; N/A), BLADE (5900/50; 2/4; 0 & 800), RESOLVE (9380/63; 2/4; 0 & 800). Treatment response was assessed at mid-RT and at 8-12 weeks post-RT using RECIST 1.1 criteria and was defined as: complete response (CR) vs non-complete response (non-CR). Pre-RT ADC was correlated with RT response (CR vs non-CR) at mid- and post-RT time points. Mann-Whitney test was used to compare ADC values between the mid-treatment CR group and the non-CR group. Recursive partitioning analysis (RPA) was done to identify ADC threshold associated with relapse. <h3>Results</h3> Fifty-nine patients with grossly visible primary tumor volume prior to RT start were included in this analysis. Patients' disease and treatment criteria are shown in Table 1. Pre-treatment ADC was not correlated with tumor response or oncologic outcomes (P>0.05). For patients with CR at the end of RT, there was a significant increase in mean ADC at mid-RT compared to baseline ((1.8 ± 0.29) × 10^–3 mm²/s <i>vs</i> (1.37 ± 0.22) × 10^–3 mm²/s, <i>p</i> <0.0001). However, patients with no-CR had no statistically significant increase (p>0.05). Median follow-up was 32 months. Patients with ≤106% delta ADC at mid-RT had significantly worse local control at 2-year compared to patients with higher delta ADC (48% vs 96%, <i>p</i> <0.0001). <h3>Conclusion</h3> Delta ADC changes is a strong predictor of local recurrence in head and neck cancer patients. Multi-institutional data is needed for validation of our results.

A study on magnetic resonance imaging in patients having perianal pathology

Introduction: Perianal region is a commonly affected area in the course of several inflammatory, infectious, and neoplastic diseases. Several imaging modalities are used in imaging evaluation of this area and magnetic resonance imaging (MRI) emerges as the imaging modality of choice due to its superb soft tissue resolution. MRI is not only useful for initial detection of perianal pathologies but also in the follow-up of these disorders. Magnetic resonance imaging (MRI), with its superb soft tissue resolution, is the imaging modality of choice for anal and perianal abnormalities.Pelvic phased array coils allow more comfortable and tolerable scans with higher signal-to-noise ratios and wider field of view. Parallel imaging techniques result in shorter scan durations T2-weighted images obtained with and without fat saturation as well as postcontrast T1-weighted images with fat suppression are the most helpful sequences. Postcontrast images are helpful, mainly for differentiating postoperative changes and chronic granulation or fibrotic tissue from active inflammation and abscess formation. Axial and coronal oblique images of the anal canal should be acquired with proper and accurate multiplanar prescription in order to get ideal images which are perpendicular and coronal to the anal canal.Materials and MethodsInclusion criteria: Patients with perianal discharge, swelling, pain or pruritus & diagnosed of having perianal pathology by MRI study (1.5 T MRI).Exclusion criteria: All patients referred to department of radiology, L G hospital, maninagar, Ahmedabad with rectal mass by MRI study (1.5 T MRI)All patients with contraindications to MRI like patients with metallic implants, claustrophobia, pacemakers and patients with contrast allergy.Study type: Retrospective study (record-based study). Consent not required for retrospective study.Results and Conclusion In our study of 50 patients, out of which 42 were males & 8 were females, the most common affected age group were between 25-35 years (42%).The most common location of fistula in our study was at 6’O – 7’O clock (36%) position followed by 12- 1’O clock (28%) position.The most common type in our study being intersphincteric type (48%) according to PARK’S classification and the most common Grade in our study being grade 1 (simple intersphincteric fistula) (26%) according to St JAMES classification.Adequate understanding of relevant pelvic anatomy and fistula classification on MRI examination is essential in providing proper assessment of perianal fistulas.Evaluation of clinically undetectable disease has significant bearing on guiding medical & surgical therapy & can help minimize recurrence & better predict outcome compared to surgical exploration.

A New Phased-Array Magnetic Resonance Imaging Receive-Only Coil for HBO2 Studies.

The paper describes a new magnetic resonance imaging (MRI) phased-array receive-only (Rx) coil for studying decompression sickness and disorders of hyperbaricity, including nitrogen narcosis. Functional magnetic resonance imaging (fMRI) is noninvasive, is considered safe, and may allow studying the brain under hyperbaric conditions. All of the risks associated with simultaneous MRI and HBO2 therapy are described in detail, along with all of the mitigation strategies and regulatory testing. One of the most significant risks for this type of study is a fire in the hyperbaric chamber caused by the sparking of the MRI coils as a result of high-voltage RF arcs. RF pulses at 128 MHz elicit signals from human tissues, and RF sparking occurs commonly and is considered safe in normobaric conditions. We describe how we built a coil for HBO2-MRI studies by modifying an eight-channel phased-array MRI coil with all of the mitigation strategies discussed. The coil was fabricated and tested with a unique testing platform that simulated the worst-case RF field of a three-Tesla MRI in a Hyperlite hyperbaric chamber at 3 atm pressure. The coil was also tested in normobaric conditions for image quality in a 3 T scanner in volunteers and SNR measurement in phantoms. Further studies are necessary to characterize the coil safety in HBO2/MRI.

Quantitative 7T sodium magnetic resonance imaging of the human brain using a 32-channel phased-array head coil: Application to patients with secondary progressive multiple sclerosis.

Apparent tissue sodium concentrations (aTSCs) determined by 23 Na brain magnetic resonance imaging (MRI) have the potential to serve as a biomarker in pathologies such as multiple sclerosis (MS). However, the quantification is hindered by the intrinsically low signal-to-noise ratio of 23 Na MRI. The purpose of this study was to improve the accuracy and reliability of quantitative 23 Na brain MRI by implementing a dedicated postprocessing pipeline and to evaluate the applicability of the developed approach for the examination of MS patients. 23 Na brain MRI measurements of 13 healthy volunteers and 17 patients with secondary progressive multiple sclerosis (SPMS) were performed at 7T using a dual-tuned 23 Na/1 H birdcage coil with a receive-only 32-channel phased array. The aTSC values were determined for normal appearing white matter (NAWM) and normal appearing gray matter (NAGM) in healthy subjects and SPMS patients. Signal intensities were normalized using the mean cerebrospinal fluid (CSF) sodium concentration determined in 37 separate patients receiving a spinal tap for routine diagnostic purposes. Five volunteers underwent MRI examinations three times in a row to assess repeatability. Coefficients of variation (CoVs) were used to quantify the repeatability of the proposed method. aTSC values were compared regarding brain regions and subject cohort using the paired-samples Wilcoxon rank-sum test. Laboratory CSF sodium concentration did not differ significantly between patients without and with MS (p = 0.42). The proposed quantification workflow for 23 Na MRI was highly repeatable with CoVs averaged over all five volunteers of 1.9% ± 0.9% for NAWM and 2.2% ± 1.6% for NAGM. Average NAWM aTSC was significantly higher in patients with SPMS compared with the control group (p = 0.009). Average NAGM aTSC did not differ significantly between healthy volunteers and MS patients (p = 0.98). The proposed postprocessing pipeline shows high repeatability and the results can serve as a baseline for further studies establishing 23 Na brain MRI as a biomarker in diseases such as MS.

Prostate MRI: Is Endorectal Coil Necessary?-A Review.

To assess the necessity of endorectal coil use in 3 Tesla (T) prostate magnetic resonance imaging (MRI), a literature review comparing the image quality and diagnostic performance with an endorectal coil (ERC) and a without endorectal coil (NERC), with a phased array coil or a wearable perineal coil (WPC), was performed. A PubMed search of 3T prostate MRI using an endorectal coil for studies published until 31 July 2021 was performed. A total of 14 studies comparing 3T prostate MRI with and without endorectal coil use were identified. The quality scores and diagnostic performances were recorded for each study. In total, five studies compared image quality; five studies compared quality and performance; and four studies compared performance of detection, size of detected lesions, accuracy of cancer localization, and aggressiveness/staging. The use of an endorectal coil improved image quality with a higher overall signal to noise ratio, posterior and peripheral zone signal to noise ratio, high b-value attenuation diffusion coefficient (ADC) signal to noise ratio, and contrast to noise ratio. Endorectal coil use improved subjective image quality for anatomic detail on T2 weighted images (T2WI) and diffusion weighted images (DWI). Endorectal coil use had less motion artifact on DWI than non-endorectal coil use, but produced a higher occurrence of other artifacts on DWI. Endorectal coils had higher sensitivity, specificity, and positive predictive value (PPV) in the detection of overall and index lesions, as well as smaller and less aggressive lesions, missing fewer and smaller lesions than non-endorectal coils. Endorectal coils had higher sensitivity than non-endorectal coils in localizing and staging lesions. Endorectal coils improved quantitative and qualitative image quality and diagnostic performance in the detection of smaller and less aggressive cancers in 3T prostate MRI.

Prostate MRI using a rigid two-channel phased-array endorectal coil: comparison with phased array coil acquisition at 3\u2009T

BackgroundTo compare image quality, lesion detection and patient comfort of 3T prostate MRI using a combined rigid two-channel phased-array endorectal coil and an external phased-array coil (ERC-PAC) compared to external PAC acquisition in the same patients.MethodsThirty three men (mean age 65.3y) with suspected (n = 15) or biopsy-proven prostate cancer (PCa, n = 18) were prospectively enrolled in this exploratory study. 3T prostate MRI including T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) was performed using an ERC-PAC versus PAC alone, in random order. Image quality, lesion detection and characterization (biparametric PI-RADSv2.1) were evaluated by 2 independent observers. Estimated signal-to-noise ratio (eSNR) was measured in identified lesions and the peripheral zone (PZ). Patient comfort was assessed using a questionnaire. Data were compared between sequences and acquisitions. Inter/intra-observer agreement for PI-RADS scores was evaluated.ResultsTwenty four prostate lesions (22 PCa) were identified in 20/33 men. Superior image quality was found for ERC-PAC compared to PAC for T2WI for one observer (Obs.1, p < 0.03) and high b-value DWI for both observers (p < 0.05). The sensitivity of PI-RADS for lesion detection for ERC-PAC and PAC acquisitions was 79.2 and 75% for Obs.1, and 79.1 and 66.7%, for Obs.2, without significant difference for each observer (McNemar p-values ≥0.08). Inter−/intra-observer agreement for PI-RADS scores was moderate-to-substantial (kappa = 0.52–0.84). Higher eSNR was observed for lesions and PZ for T2WI and PZ for DWI using ERC-PAC (p < 0.013). Most patients (21/33) reported discomfort at ERC insertion.ConclusionDespite improved image quality and eSNR using the rigid ERC-PAC combination, no significant improvement in lesion detection was observed, therefore not supporting the routine use of ERC for prostate MRI.

Cine magnetic resonance imaging of the uterus for evaluation of abnormal uterine bleeding

To assess the potential role of cine magnetic resonance imaging (MRI) in the evaluation of uterine peristalsis in women classified with abnormal uterine bleeding - endometrial (AUB-E) by measuring frequency and directionality of waveforms. This was a prospective pilot study of seven women with normal menses and eight women with AUB-E, defined as regular but excessive flow causing anemia or interfering with daily activities. Exclusion criteria included other causes of AUB in the PALM-COEIN system. Subjects were evaluated using a modified Menstrual Impact Questionnaire (MIQ). MRI studies were performed within days 1-5 of the subject's menstrual cycle using a 3.0T MRI and 8-channel cardiac phased array coil. Axial and sagittal T2-weighted fast spin echo was obtained to evaluate uterine morphology. Cine MRI imaging was performed using a single shot fast spin echo with a temporal resolution of 2 to 3 seconds over a 2 minutes sequence to evaluate frequency and directionality of uterine waveforms, repeated 2-3 times, and maximum number of waveforms per two minutes reported. Images were reviewed independently by two expert radiologists blinded to patients’ histories. Primary outcome was peristaltic frequency of the subendometrium measured as number of waveforms per two minutes. Secondary outcome was directionality. Primary outcome and MRI morphology were compared by Mann-Whitney U test. MIQ responses were compared by Fischer’s exact test and Mann-Whitney U test. Normal subjects bled an average of 3.9 days and those with AUB-E bled an average of 6.4 days (p= 0.016). Normal subjects defined their flow as light or moderate. Six of seven normal subjects reported no impact on their work, physical or social activity. In comparison, all but one subject with AUB-E defined their flow as heavy or very heavy with passage of clots or flooding (p = 0.001). All subjects with AUB-E reported effect on their daily activities (p < 0.001) and were more likely to report effect on their social activity (p < 0.001) and physical activity (p < 0.001). Subjects with AUB-E were more likely to report dysmenorrhea (p=0.041). Thirteen of fifteen women demonstrated motility of the subendometrium during cine display. Two women with AUB-E did not demonstrate waveforms. There was complete agreement between readers with regard to maximum number of waveforms per two minute cycle and directionality. Median number of waveforms in subjects with normal menses was 3 per two minutes. In patients with AUB-E, the median number of waveforms was 1 per two minutes (p=0.009). All subjects with waveforms exhibited cervico-fundal directionality during menses. Cine MRI is a feasible modality for measuring differences in the frequency of uterine peristalsis in women with AUB-E. This pilot study supports further investigation into the endometrial and myometrial contributions to abnormal bleeding in women with AUB-E.

Utility of MRI in diagnosis of molecular subtypes of breast cancer

Background: Breast cancer is a collection of diseases defined by distinct pathological (e.g., ductal, lobular, mucinous) and molecular characteristics (e.g., ER and PR, HER2 amplification, and more recently transcriptome-based classifications such as luminal and basal cancers). Molecular subtyping is beneficial for the diagnosis and individualized treatment of breast cancer.MRI is a supplemental technique to mammography and ultrasonography for the evaluation of breast lesions and to predict molecular subtypes of breast cancer. Studies have highlighted the value of DCE-MRI in reflecting the anatomic and functional properties of tumors and facilitating treatment. Objectives: The aim of this work was to assess the utility of MRI as an accurate method for detection of molecular subtypes of breast cancer. Patients and Methods: a retrospective clinical study of 2-years enrollment duration. The study was conducted at Radiology Department, Assuit University Hospitals on 50 lesions, patient age ranging from 23 to 66 years old with mean age was (46.9 ± SD) years. MR imaging studies were performed using a 1.5 T Magnetom Vision scanner with dedicated bilateral phased-array breast coil (Siemens, Erlangen, Germany). MRI sequences were 1. Axial T1WI. 2. Axial T2WI. 3. Axial STIR. 4. Axial DWI and ADC. 5. DCE-MRI. Results: The study included 50 lesions; 21 lesions were Luminal A, 15 lesions were Luminal B, 10 lesions were HER2+, and 4 lesions were TN. Histopathology 39 lesions were IDC-NOS, 1 lesion was IDC (medullary type), 7 lesions were mixed pathology IDC + DCIS, and 3 lesions were ILC. As regard the correlation between the histopathological type and grade, both were specific in differentiation between the molecular subtypes. According to the MRI findings it was found that T2 Intratumoral signal intensity, STIR, and the margin of the lesion were highly specific in differentiation, both L.N status and number were found that they were highly specific in differentiation (p <0.001), while size of the lesion, T1WI signal, ADC values were found that they were non-specific in differentiation between the molecular subtypes of breast cancer. Conclusion: Breast MRI may help in assessing different molecular subtypes of breast cancer.

Association between High Diffusion-Weighted Imaging-Derived Functional Tumor Burden of Peritoneal Carcinomatosis and Overall Survival in Patients with Advanced Ovarian Carcinoma.

ObjectiveTo investigate the association between functional tumor burden of peritoneal carcinomatosis (PC) derived from diffusion-weighted imaging (DWI) and overall survival in patients with advanced ovarian carcinoma (OC).Materials and MethodsThis prospective study was approved by the local research ethics committee, and informed consent was obtained. Fifty patients (mean age ± standard deviation, 57 ± 12 years) with stage III–IV OC scheduled for primary or interval debulking surgery (IDS) were recruited between June 2016 and December 2021. DWI (b values: 0, 400, and 800 s/mm2) was acquired with a 16-channel phased-array torso coil. The functional PC burden on DWI was derived based on K-means clustering to discard fat, air, and normal tissue. A score similar to the surgical peritoneal cancer index was assigned to each abdominopelvic region, with additional scores assigned to the involvement of critical sites, denoted as the functional peritoneal cancer index (fPCI). The apparent diffusion coefficient (ADC) of the largest lesion was calculated. Patients were dichotomized by immediate surgical outcome into high- and low-risk groups (with and without residual disease, respectively) with subsequent survival analysis using the Kaplan-Meier curve and log-rank test. Multivariable Cox proportional hazards regression was used to evaluate the association between DWI-derived results and overall survival.ResultsFifteen (30.0%) patients underwent primary debulking surgery, and 35 (70.0%) patients received neoadjuvant chemotherapy followed by IDS. Complete tumor debulking was achieved in 32 patients. Patients with residual disease after debulking surgery had reduced overall survival (p = 0.043). The fPCI/ADC was negatively associated with overall survival when accounted for clinicopathological information with a hazard ratio of 1.254 for high fPCI/ADC (95% confidence interval, 1.007–1.560; p = 0.043).ConclusionA high DWI-derived functional tumor burden was associated with decreased overall survival in patients with advanced OC.

Customized Radiofrequency Phased-Array Coil Combining Transmit-Only, Receive-Only, and Transmit/Receive Coils for Magnetic Resonance Imaging of Visual Cortex at 7 Tesla

Magnetic resonance imaging (MRI) using an ultra-high magnetic field (7 Tesla) enables detailed and non-invasive studies of the function and anatomy of the human visual cortex, which is the brain region responsible for visual signal processing. However, 7T human MRI often suffers from image shading in the occipital region due to the radiofrequency (RF) wave propagation effect. Dedicated visual cortex coils, on the other hand, often lack the capability to visualize the whole brain which is necessary for image registration. We propose a novel RF coil structure in which a 2-channel transmit and receive (TRx) coil is grafted onto the frontal part of a multi-channel transmit-only/receive-only (TORO, 4Tx/14Rx) visual cortex coil. This coil was tested for high-resolution functional MRI with an in-plane resolution of 0.5 mm. The results showed that the proposed coil achieved a higher ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times 2.5$ </tex-math></inline-formula> ) temporal signal-to-noise ratio (tSNR) in functional imaging of the visual cortex area than that of a commercial 7T whole-head coil. The added 2-channel TRx elements allowed whole-brain edge images to be acquired, enabling successful brain segmentation and atlas registration without the need for a second scan using a whole-head coil. The proposed coil structure can be useful for high-resolution visual functional MRI at very high magnetic fields due to its sensitivity, open geometry, and compatibility with the standard image processing workflow.

Diagnostic Accuracy of MRC in Benign and ML in Obstructive Jaundice Patients, Taking Histopathology as Gold Standard

Objectives: To find out the diagnostic accuracy of magnetic resonance cholangiopancreatography in benign and malignant lesions in patients of obstructive jaundice, taking histopathology as gold standard. Material and methods: This cross sectional study was conducted at Department of Radiology, Bahawal Victoria Hospital, Bahawalpur October 2019 to April 2020. A total of 164 patients with suspected cases of obstructive jaundice and age 25-65 years of either gender were included. Then magnetic resonance cholangiopancreatography (MRCP) was performed in every patient by 1.5 Tesla MR System using a torso phased-array coil. After this, each patient was undergone operation in the concerned ward. Findings of MRCP were compared with the findings of histopathology. Results: In MRCP positive patients, 78 were true positive (TP) and 13 were false positive (FP). Among 73, MRCP negative patients, 08 were false negative (FN) whereas 65 were True Negative (TN). Overall specificity, sensitivity, NPV, PPV and diagnostic accuracy of magnetic resonance cholangiopancreatography in benign and malignant lesions in patients of obstructive jaundice, taking histopathology as gold standard was 90.70%, 83.33%, 85.71%, 89.04% and 87.20% respectively. Conclusion: This study concluded that magnetic resonance cholangiopancreatography (MRCP) is the non-invasive modality of choice with diagnostic accuracy in diagnosing in benign and malignant lesions in obstructive jaundice patients. Keywords: obstructive jaundice, sensitivity, magnetic resonance imaging.