Diffusion-weighted Imaging Research Articles

Diagnostic Utility of Diffusion-Weighted Imaging in Distinguishing Common Pediatric Posterior Fossa Tumors: A Single Center Retrospective Study.

Pediatric posterior fossa tumors pose diagnostic challenges due to their diverse histopathological features and variable clinical presentations. Conventional magnetic resonance imaging (MRI) serves as the initial diagnostic tool; however, additional modalities, such as diffusion-weighted imaging (DWI), are essential for refining tumor classification. This retrospective single-center study aimed to evaluate the diagnostic utility of apparent diffusion coefficient (ADC) parameters in distinguishing between the most common pediatric posterior fossa tumors. Fifty-nine patients under the age of 18 (27 females and 32 males) with histopathologically diagnosed primary posterior fossa tumors underwent pre-treatment conventional and diffusion MRI. Apparent diffusion coefficient values were measured from solid tumor regions and normal cerebellar parenchyma, with subsequent calculation of tumor/normal cerebellar ADC ratios. The median ADC values for pilocytic astrocytomas (PAs) were 1786.2 × 10-6 mm2 /s, ependymomas 1144.9 × 10-6 mm2 /s, and for medulloblastomas 666.1 × 10-6 mm2 /s were significantly different (P < .001 for all three). Similarly, the median ADC ratios demonstrated discriminatory potential, with PAs showing the highest ratio (2.46), followed by ependymomas (1.55) and medulloblastomas (0.89) (P < .001 for all three). Receiver operating characteristic analysis revealed distinct ADC cutoffs and ratios for differentiating all tumor types from each other. Despite limitations, such as a small cohort size and different MRI protocols, our results show that ADC metrics are especially useful for distinguishing between the most common pediatric posterior fossa tumors. We recommend that future studies integrate advanced imaging techniques and larger cohorts to improve diagnostic accuracy.

Giving the prostate the boost it needs: Spiral diffusion MRI using a high-performance whole-body gradient system for high b-values at short echo times.

To address key issues of low SNR and image distortions in prostate diffusion MRI (dMRI) by means of using strong gradients, single-shot spiral readouts and an expanded encoding model for image reconstruction. Diffusion-weighted spin echo imaging with EPI and spiral readouts is performed on a whole-body system equipped with strong gradients (up to 250 mT/m). An expanded encoding model including static off-resonance, coil sensitivities, and magnetic field dynamics is employed for image reconstruction. The acquisitions are performed on a phantom and in vivo (one healthy volunteer and one patient with prostate cancer). The resulting images are compared to conventional dMRI EPI with navigator-based image reconstruction and assessed in terms of their congruence, SNR, tissue contrast, and quantitative parameters. Using the expanded encoding model, high-quality images of the prostate gland are obtained across all b-values (up to 3 ms/μm2), clearly outperforming the results obtained with conventional image reconstruction. Compared to EPI, spiral imaging provides an SNR gain up to 45% within the gland and even higher in the lesion. In addition, prostate dMRI with single-shot spirals at submillimeter in-plane resolution (0.85 mm) is accomplished. The combination of strong gradients and an expanded encoding model enables imaging of the prostate with unprecedented image quality. Replacing the commonly used EPI with spirals provides the inherent benefit of shorter echo times and superior readout efficiency and results in higher SNR, which is in particular relevant for considered applications.

Non-invasive imaging modalities for diagnosing pulsatile tinnitus: a comprehensive review and recommended imaging algorithm.

Pulsatile tinnitus (PT) is a challenging diagnostic condition arising from various vascular, neoplastic, and systemic disorders. Non-invasive imaging is essential for identifying underlying causes while minimizing risks of invasive diagnostic angiography. Although no consensus exists on the primary imaging modality for PT and currently CT, ultrasound, and MRI are used in the diagnostic pathway, MRI is increasingly preferred as the first-line screening test for its diagnostic efficacy and safety. MRI protocols such as time-of-flight, magnetic resonance angiography, diffusion-weighted imaging, and arterial spin labeling can identify serious causes, including vascular shunting lesions, venous sinus stenosis, and tumors. In this narrative review of the current literature we discuss the benefits and limitations of various non-invasive imaging modalities in identifying the characteristic imaging findings of the most common causes of PT and also provide an algorithm that clinicians can use to guide the imaging evaluation.

Decoding cortical chronotopy—Comparing the influence of different cortical organizational schemes

The brain's diverse intrinsic timescales enable us to perceive stimuli with varying temporal persistency. This study aimed to uncover the cortical organizational schemes underlying these variations, revealing the neural architecture for processing a wide range of sensory experiences. We collected resting-state fMRI, task-fMRI, and diffusion-weighted imaging data from 47 individuals. Based on this data, we extracted six organizational schemes: (1) the structural Rich Club (RC) architecture, shown to synchronize the connectome; (2) the structural Diverse Club architecture, as an alternative to the RC based on the network's module structure; (3) the functional uni-to-multimodal gradient, reflected in a wide range of structural and functional features; and (4) the spatial posterior/lateral-to-anterior/medial gradient, established for hierarchical levels of cognitive control. Also, we explored the effects of (5) structural graph theoretical measures of centrality and (6) cytoarchitectural differences. Using Bayesian model comparison, we contrasted the impact of these organizational schemes on (1) intrinsic resting-state timescales and (2) inter-subject correlation (ISC) from a task involving hierarchically nested digit sequences. As expected, resting-state timescales were slower in structural network hubs, hierarchically higher areas defined by the functional and spatial gradients, and thicker cortical regions. ISC analysis demonstrated hints for the engagement of higher cortical areas with more temporally persistent stimuli. Finally, the model comparison identified the uni-to-multimodal gradient as the best organizational scheme for explaining the chronotopy in both task and rest. Future research should explore the microarchitectural features that shape this gradient, elucidating how our brain adapts and evolves across different modes of processing.

Effects of Gadolinium Chelate Administration Timing on T2-weighted and Diffusion-weighted Abdominal MRI Examination: A Prospective Study.

Magnetic Resonance Imaging (MRI) data acquisition includes several sequences that might be optimized to reduce the scan time. This study aimed to investigate the impact of gadolinium chelate administration timing on scan duration and image quality in Diffusion-weighted Imaging (DWI) and T2-weighted Imaging (T2WI) during abdominal MRI examinations. A prospective study was conducted from October 2018 to May 2020. Study participants were assigned into a conventional group, undergoing MRI with DWI and T2WI sequences pre and post-gadolinium injection, or an optimized group, receiving MRI with DWI and T2WI sequences after gadolinium injection. Quantitative image quality, measured by the Signal-to-noise Ratio (SNR), Contrast-to-noise Ratio (CNR), and Apparent Diffusion Coefficient (ADC), was analyzed. Kappa statistics were employed for the inter-observer agreement on liver lesion detection. Our study has included 341 patients, with 168 and 173 in the conventional and optimized groups, respectively. Mean scan durations were 1,304 (±143) and 1,015 (±129) s for the conventional and optimized groups, respectively (p<0.05). For the liver, spleen, and pancreas, SNR and ADC remained statistically unchanged in post-enhanced DWI and T2WI (p>0.05). Significant decreases in the SNR and ADC of the kidney were observed in post-contrast DWI and T2WI (p<0.05). Hepatic lesion detectability did not show significant differences between pre and post-contrast DWI and T2WI images (p>0.05). DWI and T2WI sequences assessed post-gadolinium administration exhibited shortened scan time without compromising the image quality for liver, spleen, and pancreas evaluations. However, these sequences should be examined before gadolinium administration when assessing the kidneys.

Bone marrow magnetic resonance imaging (MRI): morphological and functional features from reconversion to infiltration.

Bone marrow is a dynamic organ with variable composition in relation to age or pathophysiological changes. Magnetic resonance imaging (MRI) is the technique of choice to assess the different components of the bone marrow based on the different information provided by the different characteristics of the MRI sequences. This article provides an overview of the MRI appearances of normal and abnormal bone marrow. We review the MRI features of normal developmental red marrow- to yellow-conversion, reconversion and physiologic conditions. We review the key imaging techniques used in assessing bone marrow pathology in MRI, including T1-weighted, T2-weighted, Dixon chemical shift imaging and diffusion-weighted imaging, as well as dynamic contrast-enhanced (DCE) MRI. It is discussed the bone marrow characteristics in the different morphological and functional MRI sequences from the normal or abnormal conditions such as; infiltration (metastases), proliferation [multiple myeloma (MM)], vascular edema/necrosis and postreatment changes. We show the different MRI features to differentiate physiological processes from pathological processes in order to provide effective diagnoses, as well as to evaluate the optimal therapeutic monitoring assessment. Insights from recent advancements in imaging technology and emerging MRI techniques are also discussed, providing a comprehensive overview of bone marrow MRI and its clinical implications. This review provides a useful tool for radiologist to decide normal or abnormal findings from the analysis of bone marrow MRI; in order to manage and take decisions that will depend on the imaging findings. The optimal analysis of bone marrow MRI requires knowledge of the physiology of the bone marrow to interpret properly the pathology and avoid diagnostic errors.

Familial adult-onset neuronal intranuclear inclusion disease: A case report and literature review.

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disorder with highly variable clinical manifestations, making diagnosis challenging. Recent advancements in genetic and pathological testing, such as the identification of GGC repeat expansions in the NOTCH2NLC gene, have improved diagnostic accuracy, but familial cases remain underreported. This report details 3 cases of familial adult-onset NIID in 2 sisters and 1 brother. The older sister experienced episodic encephalopathy and autonomic dysfunction for over 40 years, while the younger sister presented similar symptoms 5 years ago. The brother also developed episodic encephalopathy 5 years ago. Brain diffusion-weighted imaging (DWI) for all 3 patients revealed hyperintensity at the corticomedullary junction and corpus callosum. Skin biopsies from the older sister and brother confirmed the presence of p62 antibody-positive intranuclear inclusion bodies in sweat gland cells and fibroblasts. Genetic testing showed 146 and 133 GGC repeats in the NOTCH2NLC gene in the older sister and brother, respectively. All 3 patients were diagnosed with NIID based on clinical, radiological, and genetic findings. The patients received hormonal therapy, circulation-enhancing treatments, and rehydration therapy during acute episodes. All 3 patients showed significant improvement in symptoms following treatment, with a return to baseline function after hospital discharge. Proper management of NIID includes prompt recognition of symptoms, adequate rest, and avoidance of triggers such as fatigue, infections, and stress, which may reduce the frequency of episodic attacks. Early diagnosis and targeted symptomatic treatment are essential for improving patient outcomes.

Conjugate Vertical Gaze Palsy Related to Unilateral Midbrain Infarction

Conjugate upward and downward gaze palsy related to unilateral midbrain infarction is a rare neurological symptom, as there were few reported cases worldwide. Here, we report a case of 55-year-old male patient presenting with conjugate vertical gaze palsy. In this case, diffusion-weighted magnetic resonance images demonstrated a localized infarction in the right rostral midbrain.

Efficacy and safety of adrenomedullin for acute ischemic stroke (AMFIS): a phase 2, randomized, double-blinded, placebo-controlled, clinical trial

Adrenomedullin has angiogenic and vasoprotective effects in acute ischemic stroke (AIS). This investigator-initiated trial aimed to evaluate the safety, efficacy, and optimal administration of adrenomedullin in treating AIS. In this single-center, multi-cohort, double-blinded, randomized, placebo-controlled, Phase II trial, patients with AIS received pulsed adrenomedullin (9ng/kg/min for 8h daily over 7 days) or placebo in the first-half cohort, and continuous-pulsed adrenomedullin (9ng/kg/min for 72h during the first 3 days and 8h daily between Day 4-7) or placebo in the second-half cohort. We included male and female patients aged 20-90 years with newly confirmed ischemic lesions on diffusion-weighted magnetic resonance imaging, and for whom protocol treatment could be initiated within 24h of symptom onset. The primary safety endpoint was the occurrence of intervention-related severe adverse events. For the primary efficacy endpoint, the least square means and 95% confidence intervals of National Institutes of Health Stroke Scale (NIHSS) scores up to 7 days post-intervention initiation were calculated using generalized estimating equation models. This trial was registered at Japan Registry of Clinical Trials, jRCT2051190092. Between January 16, 2020, and November 14, 2021, 60 patients were enrolled (median [interquartile range] age, 75 [66-81] years; NIHSS score, 3 [2-4]; 21 [35.0%] females). Neither intervention-related serious adverse events nor severe adverse events were observed in patients receiving adrenomedullin. No life-threatening adverse events or deaths were reported. The least square means (95% confidence intervals) of the changes in NIHSS scores from pre-treatment to Day 7 were-0.76 (-1.43 to-0.09) in the adrenomedullin group (-1.08 [-2.17 to 0.00] in the pulsed adrenomedullin group and-0.42 [-1.12 to 0.29] in the continuous-pulsed adrenomedullin group) and-1.08 (-2.11 to-0.05) in the placebo group. Adrenomedullin was well tolerated in patients with non-severe, non-embolic AIS, although its beneficial effects were not demonstrated. It is necessary to show the efficacy of adrenomedullin in further clinical trials. Japan Agency for Medical Research and Development.

A Case of Growing Chronic Subdural Hematoma with Niveau Formation Showing an Enhanced Subdural Hyperintense Band on Magnetic Resonance Diffusion-Weighted Imaging Over Time

This case report describes an 84-year-old female patient with a growing chronic subdural hematoma (CSDH) that showed an enhanced subdural hyperintense band on magnetic resonance diffusion-weighted imaging over time, indicating that it reflects fresh bleeding from the outer membrane covering the hematoma. The presence of subdural hyperintense band on magnetic resonance diffusion-weighted imaging of CSDH, possibly reflecting hemorrhagic diathesis of the outer membrane, might be a predictor of enlargement of CSDH.

Improving MR axon radius estimation in human white matter using spiral acquisition and field monitoring.

To compare MR axon radius estimation in human white matter using a multiband spiral sequence combined with field monitoring to the current state-of-the-art echo-planar imaging (EPI)-based approach. A custom multiband spiral sequence was used for diffusion-weighted imaging at ultra-high -values. Field monitoring and higher order image reconstruction were employed to greatly reduce artifacts in spiral images. Diffusion weighting parameters were chosen to match a state-of-the art EPI-based axon radius mapping protocol. The spiral approach was compared to the EPI approach by comparing the image signal-to-noise ratio (SNR) and performing a test-retest study to assess the respective variability and repeatability of axon radius mapping. Effective axon radius estimates were compared over white matter voxels and along the left corticospinal tract. Increased SNR and reduced artifacts in spiral images led to reduced variability in resulting axon radius maps, especially in low-SNR regions. Test-retest variability was reduced by a factor of approximately 1.5 using the spiral approach. Reduced repeatability due to significant bias was found for some subjects in both spiral and EPI approaches, and attributed to scanner instability, pointing to a previously unknown limitation of the state-of-the-art approach. Combining spiral readouts with field monitoring improved mapping of the effective axon radius compared to the conventional EPI approach.

Optimizing Multiparametric MRI Protocols for Prostate Cancer Detection: A Comprehensive Assessment Aligned with PI-RADS Guidelines.

Multiparametric magnetic resonance imaging (mpMRI) is recognized as the most indicative method for diagnosing prostate cancer. The purpose of this narrative review is to provide a comprehensive evaluation aligned with the Prostate Imaging and Reporting Data System (PI-RADS) guidelines, offering an in-depth insight into the various MRI sequences used in a standard mpMRI protocol. Additionally, it outlines the critical technical requirements necessary to perform a standard mpMRI examination of the prostate, as defined by the PI-RADS specifications. European Society of Urogenital Radiology has released PI-RADS guideline detailing its suggestions aimed at improving the standards of the procedure. The purpose of this guideline is to establish a standard strategy for MRI protocols and image interpretation, aiming to prevent variability in each of the imaging and interpretation stages. A standard mpMRI protocol comprises morphological sequences and functional sequences. Morphological sequences which encompass T1- and T2-weighted images, and various functional sequences include diffusion-weighted imaging, and dynamic contrast-enhanced MRI. The PI-RADS recommendations assert that having a standard and uniform protocol for all MRI centers is imperative. Furthermore, the existence of a standardized checklist for interpreting MRI images can foster greater consensus in the process of diagnosing and treating patients. Standardized protocols and checklists for mpMRI interpretation are essential for achieving greater consensus among radiologists, ultimately leading to improved diagnostic outcomes in prostate cancer.

Diagnostic Accuracy of Magnetic Resonance Spectroscopy and Diffusion-Weighted Mri in Differentiating Between Pyogenic Brain Abscesses and Necrotic Brain Tumors

Objective: To determine the diagnostic accuracy of magnetic resonance spectroscopy plus diffusion-weighted Magnetic Resonance Imaging in differentiating pyogenic brain abscess and necrotic brain tumors, taking histopathology as the gold standard. Study Design: Validation study. Place and Duration of Study: Department of Radiology, District Headquarters Hospital, Sargodha Pakistan, Jun 2019 to May 2022. Methodology: A total of 160 patients presenting with symptoms suggestive of brain abscess or tumor, ranging from 20 to 70 years of age, irrespective of gender, were included. All patients were subjected to Magnetic Resonance Imaging including magnetic resonance spectroscopy and diffusion-weighted image. Patients were referred for biopsy to the department of neurosurgery of tertiary care hospitals. Histopathological diagnosis was taken as the gold standard for the determination of diagnostic accuracy. Results: The values for magnetic resonance spectroscopy plus diffusion-weighted Magnetic Resonance Imaging differentiating pyogenic brain abscess and necrotic brain tumor, taking histopathology as the gold standard were as follows: sensitivity 93(75%); specificity (95.31%); positive predictive value 96(77%); negative predictive value 91(04%); and diagnostic accuracy 94(38%). Conclusion: Diffusion-weighted images plus MRS are non–invasive tools with high-level diagnostic value. The combination of these modalities should be employed for accurate diagnosis, precise management, and prompt follow-up of the patients under suspicion of tumor or brain abscess.

Grading of clear cell renal cell carcinoma by using monoexponential, biexponential, and stretched exponential diffusion-weighted MR imaging.

To evaluate the diagnostic accuracy of monoexponential, biexponential and stretched-exponential diffusion-weighted imaging (DWI) models in the grading of clear cell renal cell carcinoma (ccRCC). Fifty-one patients with pathologically proven ccRCC underwent DWI with fifteen b factors (0, 10, 30, 50, 70, 100, 150, 200, 300, 400, 600, 800, 1000, 1500, 2000 sec/mm²) on a 3.0T MR scanner. The isotropic apparent diffusion coefficient (ADC), true diffusion coefficient (ADCslow), pseudodiffusion coefficient (ADCfast), and fraction of perfusion (f) were derived from DWI using a biexponential model. The water diffusion heterogeneity index (α) and distributed diffusion coefficient (DDC) were derived from DWI using a stretched-exponential model. All values were calculated for the solid area of tumors and compared between high-grade and low-grade ccRCC. The Mann-Whitney U test and receiver operating characteristic (ROC) analysis were used for statistical analysis. The DeLong test was performed to compare the ROC curves. The mean ADC, DDC, ADCslow and α values were significantly lower in high-grade ccRCC than in low-grade ccRCC (P< 0.01). However, the ADCfast and f were not significantly different between the two groups (P > 0.05). According to the ROC analyses, the AUC for α was 0.941, which was significantly greater than those of the other parameters, with a sensitivity of 100% and a specificity of 84.2%. The DeLong test showed that there were significant differences in the ROCs among ADCfast/ADC, ADCfast/α, f/ADCslow, ADCfast/ADCslow, f/α, DDC/α, and f/ADC. Diffusion-related parameters (ADC, DDC, ADCslow and α) could be used to distinguish between low- and high-grade ccRCC. The α derived from the stretched-exponential model may be the most promising parameter for grading ccRCC.

Amide proton transfer MRI may reflect effective reperfusion and predict functional outcomes in patients with ischemic stroke.

Perfusion imaging is useful to assess tissue recovery in patients with acute ischemic stroke (AIS); however, it cannot reflect tissue metabolism. We postulated that amide proton transfer (APT) imaging can characterize the tissue status after reperfusion therapy, thus providing prognostic value for 90-day functional outcomes. We included 63 patients with AIS and large-vessel occlusion (LVO). The APT signals, including APT# and NOE# (nuclear Overhauser enhancement) were quantified. Ischemic lesions observed on APT# and diffusion-weighted imaging (DWI) were classified according to their mismatch patterns (APT# < DWI; APT# ≥ DWI). Predictors of 90-day good outcomes (modified Rankin scale score 0-2) were evaluated. Patients with successful reperfusion exhibited higher APT#, smaller percentage change of APT#, and a greater likelihood of presenting APT# < DWI compared to those with poor reperfusion (all P < 0.05). The APT# (odds ratio [OR] = 11.48, P = 0.046) and a mismatch pattern of APT# < DWI (OR = 7.41, P = 0.020) independently predicted good outcomes besides the clinical parameters. A mismatch pattern of APT# ≥ DWI was a significant marker of poor outcomes despite successful reperfusion (P = 0.002). Our study provides preliminary evidence that APT may reveal tissue recovery after reperfusion and predict good outcomes at 90 days in patients with AIS and LVO.

A neuromuscular clinician's guide to magnetic resonance neurography.

Magnetic resonance neurography (MRN) is increasingly used in clinical practice for the evaluation of patients with a wide spectrum of peripheral nerve disorders. This review article discusses the technical aspects of MRN highlighting the core sequences performed for clinical care. A robust, high-resolution, heavily T2-weighted fluid-sensitive sequence performed on a 3.0 Tesla magnet system remains the main workhorse MRN sequence. In specific clinical scenarios, adjunct techniques such as diffusion-weighted imaging can be added to a protocol for disease characterization. In addition, gadolinium-based contrast material can also be administered for the purposes of image optimization (suppress adjacent vascular signal) and disease characterization. Technical modifications to field of view and planes of imaging can be made based on the clinical question and discussion with the radiologist(s). On fluid-sensitive MRN sequences, a normal peripheral nerve exhibits iso- to minimally hyperintense signal relative to skeletal muscle with a predictable trajectory, preserved "fascicular" architecture, and tapered caliber from proximal to distal. Peripheral nerve abnormalities on MRN include alterations in signal, caliber, architecture, diffusion characteristics as well as enhancement and provide information regarding the underlying etiology. Although some MRN findings including nerve hyperintensity and long-segmental enlargement are nonspecific, there are certain diagnoses that can be made with high certainty based on imaging including benign peripheral nerve tumors, high-grade peripheral nerve injury, and intraneural ganglia. The purpose of this article is to familiarize a neuromuscular clinician with fundamentals of MRN acquisition and interpretation to facilitate communication with the neuromuscular radiologist and optimize patient care.

Significance of cerebral microinfarcts in antiphospholipid syndrome: A population-based study.

Acute ischemic stroke (AIS) or transient ischemic attack (TIA) is the most common neurological manifestations of patients with antiphospholipid syndrome (APS). Incidental diffusion-weighted imaging (DWI) positive subcortical and cortical lesions, or acute incidental cerebral microinfarcts (CMI), are microscopic ischemic lesions, detectable on MRI for 10-14 days only. We aimed to look at the prevalence of acute incidental CMI in a cohort of patients with APS and their association with subsequent AIS or TIA. This is a population-based cohort study of adults with APS diagnosis using International Statistical Classification-9 (ICD-9) and supporting laboratory results between January 2014 and April 2020. We included any patient undergoing brain MRI (index event) during the year prior APS diagnosis or at any time point following diagnosis. Age-matched subjects with negative APS laboratory workup were used as a control group. In the first analysis, we compared acute incidental CMI prevalence in both groups. We then performed a second analysis among APS patients only, comparing patients with and without acute incidental CMI for AIS or TIA as the primary outcome. Cox proportional hazards models used to calculate hazards ratio (HR) and 4 years cumulative risk. 292 patients were included, of which, 207 patients with APS. Thirteen patients with APS had acute incidental CMI on MRI (6.3%), compared with none in the control group (p = 0.013). Following multivariable analysis, APS was the sole factor associated with acute incidental CMI (p = 0.026). During a median follow-up of 4 years (IQR 3.5, 4) in patients with APS, following multivariable analysis, acute incidental CMI was associated with subsequent AIS or TIA (HR 6.73 [(95% CI, 1.96-23.11], p < 0.01). Acute incidental CMI are more common among patients with APS than in patients with negative APS tests, and are associated with subsequent AIS or TIA. Detecting acute incidental CMI in patients with APS may guide etiological workup and reevaluation of antithrombotic regimen.

Quality control of quantitative diffusion-weighted magnetic resonance imaging: metrological problems

Quality control of quantitative diffusion-weighted magnetic resonance imaging: metrological problems

129Xe Image Processing Pipeline: An open-source, graphical user interface application for the analysis of hyperpolarized 129Xe MRI.

Hyperpolarized 129Xe MRI presents opportunities to assess regional pulmonary microstructure and function. Ongoing advancements in hardware, sequences, and image processing have helped it become increasingly adopted for both research and clinical use. As the number of applications and users increase, standardization becomes crucial. To that end, this study developed an executable, open-source 129Xe image processing pipeline (XIPline) to provide a user-friendly, graphical user interface-based analysis pipeline to analyze and visualize 129Xe MR data, including scanner calibration, ventilation, diffusion-weighted, and gas exchange images. The customizable XIPline is designed in MATLAB to analyze data from all three major scanner platforms. Calibration data is processed to calculate optimal flip angle and determine129Xe frequency offset. Data processing includes loading, reconstructing, registering, segmenting, and post-processing images. Ventilation analysis incorporates three common algorithms to calculate ventilation defect percentage and novel techniques to assess defect distribution and ventilation texture. Diffusion analysis features ADC mapping, modified linear binning to account for ADC age-dependence, and common diffusion morphometry methods. Gas exchange processing uses a generalized linear binning for data acquired using 1-point Dixon imaging. The XIPline workflow is demonstrated using analysis from representative calibration, ventilation, diffusion, and gas exchange data. The application will reduce redundant effort when implementing new techniques across research sites by providing an open-source framework for developers. In its current form, it offers a robust and adaptable platform for 129Xe MRI analysis to ensure methodological consistency, transparency, and support for collaborative research across multiple sites and MRI manufacturers.

Exploring the feasibility of FOCUS DWI with deep learning reconstruction for breast cancer diagnosis: A comparative study with conventional DWI.

This study compared field-of-view (FOV) optimized and constrained undistorted single-shot diffusion-weighted imaging (FOCUS DWI) with deep-learning-based reconstruction (DLR) to conventional DWI for breast imaging. This study prospectively enrolled 49 female patients suspected of breast cancer from July to December 2023. The patients underwent conventional and FOCUS breast DWI and data were reconstructed with and without DLR. Two radiologists independently evaluated three images per patient using a 5-point Likert scale. Objective evaluations, including signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC), were conducted using manual region of interest-based analysis. The subjective and objective evaluations were compared using the Friedman test. The scores for the overall image quality, anatomical details, lesion conspicuity, artifacts, and distortion in FOCUS-DLR DWI were higher than in conventional DWI (all P < 0.001). The SNR of FOCUS-DLR DWI was higher than that of conventional and FOCUS DWI (both P < 0.001), while FOCUS and conventional DWI were similar (P = 0.096). Conventional, FOCUS, and FOCUS-DLR DWI had similar CNR and ADC values. Our findings indicate that images produced by FOCUS-DLR DWI were superior to conventional DWI, supporting the applicability of this technique in clinical practice. DLR provides a new approach to optimize breast DWI.