High-resolution Magnetic Resonance Imaging Research Articles

Abstract TP160: Deep tiny flow voids on high-resolution magnetic resonance imaging predict a favorable prognosis in patients with acute middle cerebral artery occlusion

Background and Purpose: Deep tiny flow voids (DTFVs) are a specific type of collaterals surrounding chronic steno-occlusive middle cerebral artery (MCA), which can be identified on high-resolution magnetic resonance imaging (HR-MRI). This study aimed to investigate the presence of DTFVs in patients with acute MCA occlusion and their relevance to clinical outcomes. Methods: Using data from two multicenter cohort studies, we examined the presence of DTFVs in patients with acute MCA occlusion and analyzed their clinical and imaging characteristics. Univariable and multivariable logistic and linear regression analyses were conducted to assess the correlation between DTFVs and the 90-day modified Rankin Scale (mRS) scores. We further studied the mediating effect of residual flow distal to MCA occlusion on the relationship between DTFVs and 90-day mRS scores using mediation analysis. Results: One hundred and twenty-three patients with acute MCA occlusion were included. The median age was 61 years (interquartile range [IQR], 51-67 years), and 73.73% of the patients were male. The median time from symptom onset to imaging was 44 hours (IQR, 25-67 hours). Sixty-six patients (53.66%) exhibited DTFVs on HR-MRI. Lower baseline NIHSS scores (4.5 [2-8] vs. 10 [4-14]) and smaller infarct volumes (5.76 [2.79-15.34] cm 3 vs. 19.01 [7.16-83.59] cm 3 ) were observed in patients with DTFVs compared to those without. Both multivariable logistic regression (odds ratio [OR]: 6.22, 95% confidence interval [CI]: 1.82 to 21.29, p = 0.004) and linear regression analysis (β: -0.60, 95% CI: -1.06 to -0.14, p = 0.012) indicated that patients with DTFVs exhibited better 90-day functional outcomes. The mediating effect analysis showed that the effect of DTFV on 90-day mRS scores was partially mediated by residual flow distal to MCA occlusion, with a proportion of 30.66% (95% CI: 8.97 to 69.29, p = 0.002). Conclusions: In our study population, the presence of DTFVs was associated with a favorable outcome in patients with acute MCA occlusion, which may exert a protective effect partly by contributing to the formation of distal residual flow at the occlusion sites. Future studies are needed to investigate the potential of DTFVs in guiding individualized treatment strategies.

Prognostic study of intracranial branch atheromatous disease in the blood-supplying areas of the lenticulostriate and paramedian pontine arteries.

Branch atheromatous disease (BAD) is prone to early neurological deterioration (END), leading to a poor prognosis. The most common arteries causing END are the lenticulostriate arteries (LSA) and the paramedian pontine arteries (PPA). To gain insight into the characteristics of symptomatic plaques and their association with poor prognosis in patients with BAD, we conducted a prospective study using high-resolution magnetic resonance imaging (HRMRI). A total of 75 patients with BAD in the vascular range of LSA or PPA were recruited for this study. The vascular and plaque features of the carrier middle cerebral artery (MCA) and basilar artery (BA) were evaluated through the application of HRMRI, and the local cerebral blood flow (CBF) of the lesion was assessed through pseudo-continuous arterial spin-labeling (pCASL), and the number and location of cerebral microbleeds (CMBs) were documented by susceptibility-weighted imaging (SWI). Univariable and multivariable logistic regression analyses were performed to analyze the factors that affected the prognosis. A poor prognosis was observed in 24 patients (32%) with BAD. A total of 28 patients (37%) developed END. Multifactorial analysis showed statistically significant differences in the dorsal plaque of BA (OR: 19.15, 95% CI 1.72-385.37, p=0.028), male (OR: 26.22, 95% CI 3.18-406.31, p=0.007), and NIHSS at 7 days of onset (OR: 2.24, 95% CI 1.4-4.45, p=0.004). In patients with BAD in LSA and PPA areas, the dorsal plaque of BA, male, and NIHSS at 7 days of onset were independent risk factors for poor prognosis.

Management of patients with locally advanced rectal cancer in the total neoadjuvant therapy (TNT) era: Experience from Argentina.

85 Background: In the last years a paradigm shift has changed the way we manage non metastatic rectal cancer. The varied options within TNT have gradually been adapted in our country. This study aims to depict the strategies implemented. Methods: A prospective and retrospective observational study was performed from 2020 to 2024 including stage II-III rectal cancer patients treated at three centers in Buenos Aires, Argentina. Data was extracted from medical records. Results: 68 patients were included in the analysis. Median age was 59 years (IQR 48–71). 72% were male. 88% (60) had stage III disease, and 12% (8) stage II. Geriatric assessment was performed in 7 of 19 patients aged over 70 (5 frail). All patients were staged with high resolution MRI and discussed in multidisciplinary tumor board. Mismatch repair was assessed in 72%(49) of patients, only one had MLH1 deficiency. 79%(54) patients received TNT: 22%(12) short course vs 78%(42) long course radiotherapy; 24%(13) induction vs 76%(41) consolidation chemotherapy. Preferred chemotherapy regimen was CAPOX both in induction and consolidation chemotherapy (69.7% and 63.4%, respectively) Despite small numbers non significant differences in risk factors were found between TNT vs non TNT groups (Table). We registered 13 Grade 3-4 toxicity events: 3 in induction chemotherapy, 7 in consolidation and 3 in radiotherapy. Clinical complete response was achieved in 25.9% of TNT (11 consolidation, 3 induction) and 7.1%(1) of non-TNT (p=0.25). Watch and Wait was employed in 9 patients in TNT and 1 in non TNT group. 40 patients underwent surgery in the TNT and 11 in the non-TNT group; complete pathological response was reached in 17.5% (7) and 9% (1), respectively. Overall relapse rate was 19.14% (13): 2.94% (2) local and 16.2% (11) systemic. (TNT: 1.85%(1) local vs 18.5%(10) metastatic; nonTNT: 7.14%(1) both local and metastatic) p=0.4. At a median follow-up of 20 months (IQR 15–32 months), 2-year progression-free survival (PFS) rate was 87% (95% CI: 38–98%) in the non-TNT group and 78% (95% CI: 61–88%) in the TNT group. Conclusions: This study highlights the feasibility of worldwide adoption of TNT. We describe the preferred regimens and results of TNT in three high volume centers in Argentina. Long course radiotherapy and consolidation treatment with CAPOX are the predominant strategies. Non operative management is routinely offered to complete responders. Our efficacy results are comparable with published literature. Comprehensive geriatric assessment is recommended but still partially applied. In line with recent findings MMR testing has been widely adopted as an initial workup parameter. TNT %(n=54) non-TNT %(n=14) p T4 disease 26 (14) 21 (3) 0.99 N2 37 (20) 29 (4) 0.75 EMVI positivity 49 (26) 18 (3) 0.16 Circumferential resection margin <1 mm 29.6 (16) 28.57 (4) 0.23 Low-lying tumors 33 (18) 43 (6) 0.54

A foundation model with weak experiential guidance in detecting muscle invasive bladder cancer on MRI.

Preoperative detection of muscle-invasive bladder cancer (MIBC) remains a great challenge in practice. We aimed to develop and validate a deep Vesical Imaging Network (ViNet) model for the detection of MIBC using high-resolution T2-weighted MR imaging (hrT2WI) in a multicenter cohort. ViNet was designed using a modified 3D ResNet, in which, the encoder layers were pretrained using a self-supervised foundation model on over 40,000 cross-modal imaging datasets for transfer learning, and the classification modules were weakly supervised by an experiential knowledge-domain mask indicated by a nnUNet segmentation model. Optimal ViNet model was trained in derivation data (cohort 1, n=312) and validated in multicenter data (cohort 2, n=79; cohort 3, n=44; cohort 4, n=56) across a multi-ablation-test for model selection. In internal validation, ViNet using hrT2WI outperformed all ablation-test models (odds ratio [OR], 7.41 versus 1.85-2.70; all P<0.05). In external validation, the performance of ViNet using hrT2WI versus ablation-test models was heterogeneous (OR, 1.31-3.89 versus 0.89-9.75; P=0.03-0.15). In addition, clinical benefit of ViNet was evaluated between six readers using the Vesical Imaging-Reporting and Data System (VI-RADS) versus ViNet-adjusted VI-RADS. As a result, ViNet-adjusted VI-RADS upgraded 62.9% (17/27) of MIBC missed in VI-RADS score 2, while downgraded 84.1% (69/84), 62.5% (35/56) and 67.9% (19/28) of non-muscle-invasive bladder cancer (NMIBC) overestimated in VI-RADS score 3-5. We concluded that ViNet presents a promising alternative for diagnosing MIBC using hrT2WI instead of conventional multiparametric MRI.

The value of hippocampal sub-region imaging features for the diagnosis and severity grading of ASD in children

BackgroundHippocampal structural changes in Autism Spectrum Disorder (ASD) are inconsistent. This study investigates hippocampal subregion changes in ASD patients to reveal intrinsic hippocampal anomalies. MethodsA retrospective study from Hainan Children’s Hospital database (2020–2023) included ASD patients and matched controls. We classified ASD participants based on severity, dividing all subjects into four groups: normal, mild, moderate, and severe. High-resolution T1-weighted MRI images were analyzed for hippocampal subregion segmentation and volume calculations using Freesurfer. Texture features were extracted via the Gray-Level Co-occurrence Matrix. The Receiver Operating Characteristic curve was used to evaluate seven random forest predictive models constructed from volume, subregion, and texture features, as well as their combinations following feature selection. ResultsThe study included 114 ASD patients (98 boys, 2–8 years; 16 girls, 2–6 years; 17 mild, 57 moderate, 40 severe) and 111 healthy controls (HCs). No significant differences in volumes were found between ASD patients and HCs (adjusted P-value >0.05). The seven random forest models showed that single volume and texture features performed poorly for ASD classification; however, integrating various feature types improved AUC values. Further selection of texture, subregion, and volume features enhanced AUC performance across normal and varying severity categories, demonstrating the potential value of specific subregions and integrated features in ASD diagnosis. ConclusionRandom forest models revealed that hippocampal volume, texture features, and subregion characteristics are crucial for diagnosing and assessing the severity of ASD. Integrating selected texture and subregion features optimized diagnostic efficacy, while combining texture, subregion, and volume features further improved severity grading effectiveness.

Deep Learning-Based Precontrast CT Parcellation for MRI-Free Brain Amyloid PET Quantification.

This study aimed to develop a deep learning (DL) model for brain region parcellation using CT data from PET/CT scans to enable accurate amyloid quantification in 18F-FBB PET/CT without relying on high-resolution MRI. A retrospective dataset of PET/CT and T1-weighted MRI pairs from 226 individuals (157 with mild cognitive impairment or dementia and 69 healthy controls) was used. The dataset was split into training/validation (60%) and test (40%) sets. Utilizing auto-generated segmentation labels, 3 UNets were independently trained for multiplanar brain parcellation on CT and subsequently ensembled. Amyloid load was measured across 46 volumes of interest (VOIs), derived from the Desikan-Killiany-Tourville atlas. Dice similarity coefficient between the proposed CT-based DL model and MRI-based (FreeSurfer) method was calculated, with SUVR comparison using linear regression analysis and intraclass correlation coefficient. Global SUVRs were also compared within groups with clinical dementia ratings (CDRs) of 0, 0.5, and 1. The DL-based CT parcellation achieved mean Dice similarity coefficients of 0.80 for all 46 VOIs, 0.72 for 16 cortical and limbic VOIs, and 0.83 for 30 subcortical VOIs. For regional and global SUVR comparisons, the linear regression yielded a slope, y-intercept, and R2 of 1 ± 0.027, 0 ± 0.040, and ≧0.976, respectively (P < 0.001), and the intraclass correlation coefficient was ≧0.988 (P < 0.001). For global SUVRs in each CDR group, these values were 1 ± 0.020, 0 ± 0.026, ≧0.993, and ≧0.996, respectively (P < 0.001). Both MRI-based and CT-based global SUVR showed a consistent increase as the CDR score increased. The DL-based CT parcellation agrees strongly with MRI-based methods for amyloid PET quantification.

Hierarchical loop formation in human midgut during physiological umbilical herniation.

This study aimed to describe the morphological alterations that occur in the midgut and mesentery over time during the herniated phase of the midgut. The primary loop, a single hairpin-shaped loop, becomes recognizable at Carnegie stage (CS) 16. This loop projects toward the umbilical cord and subsequently gives rise to four secondary loops in the midgut of human embryos. As development advances, the segments corresponding to each secondary loop further develop into an increasing number of loops, referred to as tertiary loops. The mesenteric leaves and the narrowing parts, which serve as the borders of the secondary loops, remain identifiable throughout the subsequent stages of development. A total of 47 human embryos between CS16 and CS23 and two fetuses in the physiological umbilical herniated stage were selected for high-resolution magnetic resonance imaging acquisition. Specimens were obtained from the Congenital Anomaly Research Center of Kyoto University. Serial tissue sections obtained from four embryos were subjected to histological observation. The midgut and mesentery were reconstructed in three dimensions, and the resulting morphological changes were observed and analyzed. Formation of the primary loop was observed in all specimens between CS16 and CS18. Secondary loops in the midgut were initially discerned at CS19 in segments 2 and 4 (S2 and S4). The border between S3 and S4 was identified at the apex of the midgut hernia, where traces of the vitelline artery and duct enter the mesentery. At CS21 and later stages of development, the presence of three borders at the exact location delineated by mesenteric narrowing was consistently observed, which resulted in the midgut being divided into four segments in all specimens. The formation of tertiary loops was initially identified at CS 21, occurring in either segment S2 or S3. By CS23, tertiary loops were observed in three segments in most specimens. Notably, the initial formation of tertiary loops in S4 occurred one CS later than in S2 or S3. Additionally, the increase in the number of folds and the length per fold in S4 was delayed compared with the number and length of folds observed in both S2 and S3. The number of loops in S1 remained constant (one secondary loop) across all specimens. Upon reaching a critical threshold length, the number of loops exhibited a marked increase, accompanied by rapid elongation in S2, S3, and S4. The number of tertiary loops increased in accordance with the crown-rump length, which exhibited a maximum of 19 tertiary loops in S2 to S4 of the midgut. These findings support the hypothesis that tertiary loops develop biomechanically through the rapid elongation of the midgut and slow growth of the mesentery. This study describes the morphological alterations occurring in the midgut and mesentery over time during the herniated phase of the midgut and provides a comprehensive understanding of the roles of genetic and biomechanical factors in loop formation.

The structural effects of transcranial magnetic stimulation on hippocampal subfields in Alzheimer's disease

Aim: This study investigates the structural effects of repetitive transcranial magnetic stimulation (rTMS) on hippocampal subfields and cortical shape metrics in Alzheimer’s disease (AD) patients. Using high-resolution MRI segmentation and analysis via Hippunfold, we aim to elucidate TMS-induced structural changes and assess its potential neuroprotective role. Methods: This retrospective study included 17 AD patients and 18 healthy controls (HC). AD patients underwent 20 Hz rTMS targeting the left lateral parietal cortex over 10 sessions across two weeks. Magnetic resonance imaging (MRI) data were acquired before and after rTMS and analyzed with Hippunfold to segment hippocampal subfields and extract cortical thickness and shape metrics. Statistical analyses were performed to compare subfield volumes and cortical metrics between groups and across time points. Results: Hippocampal volumetric analysis revealed significant atrophy in subfields such as Cornu Ammonis 1, (CA1), CA2, CA4, dentate gyrus (DG), subiculum, and stratum radiatum-lacunosum-moleculare (SRLM) in AD patients compared to HC. Although no significant volumetric recovery was observed post-TMS, a further decline was noted in the right CA3 subfield (p=0.005), highlighting progressive atrophy. Cortical shape analyses showed significant reductions in hippocampal thickness (p

High-resolution direct magnetic resonance imaging fistulography with hydrogen peroxide for diagnosing anorectal fistula: A preliminary retrospective study.

Fistula-in-ano is an abnormal tunnel formation linking the anal canal with the perineum and perianal skin. Multiple imagining methods are available to evaluate it, among which magnetic resonance imaging (MRI) is the most advanced noninvasive preoperative method. However, it is limited in its visualization function. To investigate the use of intraluminal MRI for perianal fistulas via a novel direct MRI fistulography method. We mixed 3% hydrogen peroxide (HP) with gadolinium for HPMRI fistulography, retrospectively analyzing 60 cases of complex/recurrent fistula-in-ano using physical examination, trans-perineal ultrasonography (TPUS), low-spatial-resolution MRI, and high-resolution direct HPMRI fistulography. We assessed detection rates of fistula tracks, internal openings, their relationship with anal sphincters, and perianal abscesses using statistical analyses, including interobserver agreement (Kappa statistic), and compared results with intraoperative findings. Surgical confirmation in 60 cases showed that high-resolution direct HPMRI fistulography provided superior detection rates for internal openings (153) and fistula tracks (162) compared to physical exams, TPUS, and low-spatial-resolution MRI (Z > 5.7, P < 0.05). The effectiveness of physical examination and TPUS was also inferior to that of our method for detecting perianal abscesses (54) (Z = 6.773, 3.694, P < 0.05), whereas that of low-spatial-resolution MRI was not significantly different (Z = 1.851, P = 0.06). High-resolution direct HPMRI fistulography also achieved the highest interobserver agreement (Kappa: 0.89, 0.85, and 0.80), while low-spatial-resolution MRI showed moderate agreement (Kappa: 0.78, 0.74, and 0.69). TPUS and physical examination had lower agreement (Kappa range: 0.33-0.63). High-resolution direct HPMRI fistulography enhances the visualization of recurrent and complex fistula-in-ano, including branched fistulas, allowing for precise planning and improved surgical outcomes.

Diagnostic value of 11C-Methionine PET-CT imaging in persistent or recurrent Cushing's disease after surgery.

Equivocal or negative pituitary magnetic resonance imaging (MRI) findings raise a significant challenge in the management of persistent or recurrent Cushing's disease (CD), compromising the chances of success of a further transsphenoidal surgery (TSS). The aim of our study was to determine the diagnostic utility of 11C-methionine (MET) positron emission tomography coupled with computerized tomography (PET/CT) in localizing the residual or relapsing corticotroph adenoma. We retrospectively analyzed the results of 11C-MET PET/CT performed in two tertiary medical centers between May 2002 and November 2023 in 22 patients with a persisting or recurrent CD after initial TSS and equivocal or negative pituitary MRI findings. In 15 cases, images obtained from MET PET/CT were also co-registered with high-resolution 3D T1 or FLAIR MRI pituitary imaging. All patients had a proven CD at the time of first surgery. Twenty-two patients were included (18 females and 4 males), with a mean age of 36 years at diagnosis. Initial tumors were mostly microadenomas with a mean maximum tumor diameter of 6.5 mm. Thirteen out of the 22 patients had a suspect anomaly on conventional MRI that could however not be clearly distinguished from postsurgical changes, while the remaining 9 had a negative MRI. A maximal metabolic activity in the suspected area of the tumor residue (SUVmaxT) was found in 14 patients (63.5%; 5/9 patients with negative pituitary MRI and 9/13 with equivocal findings). On the basis of positive imaging, repeat TSS was performed in 12 patients and was successful in 7, while Gamma Knife radiosurgery (GKRS) was performed in 2 patients allowing remission in both (total remission rate of 64%). Among the 5 patients not cured by TSS, the presence of a corticotroph adenoma in the resected tissue was found in 3 cases. Therefore, when positive, 11C-MET PET/CT had a detection rate accuracy of 86% (12/14). Out of the 8 PET-negative patients, exploratory TSS was performed in 2, with no remission, and GKRS was performed in another two patients, with long-term remission in one. 11C-Methionine PET/CT imaging can provide valuable diagnostic information to detect a corticotroph microadenoma in more than half of patients with persistent or recurrent CD and equivocal or negative MRI findings, thereby allowing targeted TSS or radiosurgery with a global success rate of 64% in the selected subgroup with positive imaging.

Uncertainty quantification in multi-parametric MRI-based meningioma radiotherapy target segmentation

PurposeThis work investigates the use of a spherical projection-based U-Net (SPU-Net) segmentation model to improve meningioma segmentation performance and allow for uncertainty quantification.MethodsA total of 76 supratentorial meningioma patients treated with radiotherapy were studied. Gross tumor volumes (GTVs) were contoured by a single experienced radiation oncologist on high-resolution contrast-enhanced T1 MRI scans (T1ce), and both T1 and T1ce images were utilized for segmentation. SPU-Net, an adaptation of U-Net incorporating spherical image projection to map 2D images onto a spherical surface, was proposed. As an equivalence of a nonlinear image transform, projections enhance locoregional details while maintaining the global field of view. By employing multiple projection centers, SPU-Net generates various GTV segmentation predictions, the variance indicating the model’s uncertainty. This uncertainty is quantified on a pixel-wise basis using entropy calculations and aggregated through Otsu’s method for a final segmentation.Results/conclusionThe SPU-Net model poses an advantage over traditional U-Net models by providing a quantitative method of displaying segmentation uncertainty. Regarding segmentation performance, SPU-Net demonstrated comparable results to a traditional U-Net in sensitivity (0.758 vs. 0.746), Dice similarity coefficient (0.760 vs. 0.742), reduced mean Hausdorff distance (mHD) (0.612 cm vs 0.744 cm), and reduced 95% Hausdorff distance (HD95) (2.682 cm vs 2.912 cm). SPU-Net not only is comparable to U-Net in segmentation performance but also offers a significant advantage by providing uncertainty quantification. The added SPU-Net uncertainty mapping revealed low uncertainty in accurate segments (e.g., within GTV or healthy tissue) and higher uncertainty in problematic areas (e.g., GTV boundaries, dural tail), providing valuable insights for potential manual corrections. This advancement is particularly valuable given the complex extra-axial nature of meningiomas and involvement with dural tissue. The capability to quantify uncertainty makes SPU-Net a more advanced and informative tool for segmentation, without sacrificing performance.

Sex differences in intracranial plaque burden in patients with type 2 diabetes mellitus with acute ischemic cerebrovascular disease: a pilot study based on high-resolution MRI

BackgroundAtherosclerosis (AS) is the main cause of macrovascular disease. Previous studies have found sex differences in the prevalence of type 2 diabetes mellitus (T2DM) and its associated macrovascular disease outcomes. However, the relationship between sex differences, T2DM, and AS is not fully understood. This study attempts to explore possible associations between sex, treatment, and the burden of intracranial atherosclerosis (ICAS) in patients with T2DM who have experienced an acute ischemic cerebrovascular disease.MethodsWe focused on patients with T2DM with acute ischemic stroke or transient ischemic attack due to intracranial atherosclerotic stenosis. ICAS was assessed by 3T cardiovascular magnetic resonance vascular wall imaging. Plaque counts of the total, proximal, and distal intracranial arteries were used to assess plaque burden. Patients with a history of T2DM and currently taking hypoglycemic drugs were defined as being treated. Poisson regression models or negative binomial regression models were used to analyze the interaction between sex and treatment in relation to plaque burden.ResultsA total of 495 plaques were detected in 120 patients (75 male; mean age, 60.77 ± 11.01 years), including 311 proximal and 184 distal plaques. The intracranial culprit plaque was located proximal to the artery in both male (85.3%) and female (88.9%) patients. The adjusted total and proximal intracranial plaque burdens were 1.261 times (95% confidence interval [CI], 1.050–1.515, P=0.013) and 1.322 times (95%CI, 1.055–1.682, P=0.016) higher in male than in female patients. The risk ratio for proximal plaque burden in untreated male versus female patients was 0.966 (95%CI, 0.704–1.769). However, the proximal plaque risk ratio for treated male versus female patients was 1.530 (95%CI, 1.076–2.174). The interaction of sex and treatment significantly affected the proximal plaque burden.ConclusionMale patients with T2DM and acute cerebrovascular disease have a significantly higher adjusted risk of total and proximal intracranial plaque burden compared to female patients. Female patients undergoing antidiabetic treatment have a significantly reduced risk of proximal plaque to males. Considering that culprit plaques tend to accumulate in the proximal arteries, understanding how to reduce the burden of proximal plaques may help reduce the risk of adverse cerebrovascular events.

Conditional diffusion-generated super-resolution for myocardial perfusion MRI

IntroductionMyocardial perfusion MRI is important for diagnosing coronary artery disease, but current clinical methods face challenges in balancing spatial resolution, temporal resolution, and slice coverage. Achieving broader slice coverage and higher temporal resolution is essential for accurately detecting abnormalities across different slice locations but remains difficult due to constraints in acquisition speed and heart rate variability. While techniques like parallel imaging and compressed sensing have significantly advanced perfusion imaging, they still suffer from noise amplification, residual artifacts, and potential temporal blurring due to the rapid transit of dynamic contrast vs. the temporal constraints of the reconstruction.MethodsThis study introduces a conditional diffusion-based generative model for myocardial perfusion MRI super resolution, addressing the trade-offs between spatiotemporal resolution and slice coverage. We adapted Denoising Diffusion Probabilistic Models (DDPM) to enhance low-resolution perfusion images into high-resolution outputs without requiring temporal regularization. The forward diffusion process introduces Gaussian noise incrementally, while the reverse process employs a U-Net architecture to progressively denoise the images, conditioned on the low-resolution input image.ResultsWe trained and validated the model on a retrospective dataset of dynamic contrast-enhanced (DCE) perfusion MRI, consisting of both stress and rest images from 47 patients with heart disease. Our results showed significant image quality improvements, with a 5.1% reduction in nRMSE, a 1.1% increase in PSNR, and a 2.2% boost in SSIM compared to GAN-based super-resolution method (P &amp;lt; 0.05 for all metrics using paired t-test) in retrospective study. For the 9 prospective subjects, we achieved a total nominal acceleration of 8.5-fold across 5–6 slices through a combination of low-resolution acquisition and GRAPPA. PerfGen outperformed GAN-based approach in sharpness (4.36 ± 0.38 vs. 4.89 ± 0.22) and overall image quality (4.14 ± 0.28 vs. 4.89 ± 0.22), as assessed by two experts in a blinded evaluation (P &amp;lt; 0.05) in prospective study.DiscussionThis work demonstrates the capability of diffusion-based generative models in generating high-resolution myocardial perfusion MRI from conditional low-resolution images. This approach has shown the potentials to accelerate myocardial perfusion MRI while enhancing slice coverage and temporal resolution, offering a promising alternative to existing methods.

3D MRI with CT-like bone contrast (3D-BONE): a pictorial review of clinical applications.

Computed tomography (CT) is the gold standard imaging modality for the assessment of 3D bony morphology but incurs the cost of ionizing radiation exposure. High-resolution 3D magnetic resonance imaging (MRI) with CT-like bone contrast (CLBC) may provide an alternative to CT in allowing complete evaluation of both bony and soft tissue structures with a single MRI examination. To review the technical aspects of an optimized stack-of-stars 3D gradient recalled echo pulse sequence method (3D-Bone) in generating 3D MR images with CLBC, and to present a pictorial review of the utility of 3D-Bone in the clinical assessment of common musculoskeletal conditions. 3D-Bone is a black-bone imaging technique for acquiring high-resolution 3D MR images with strong CLBC, achieved by first rendering as high a signal as possible from non-cortical bone tissues, and second by minimizing signal contrast between non-cortical bone tissues. 3D-Bone can be used in the clinical evaluation of bony morphology in common musculoskeletal conditions. Advantages include strong bone-soft tissue contrast, resistance to motion artefacts, simple hardware and software requirements, and straightforward image processing. Disadvantages include non-specificity for cortical bone, sensitivity to susceptibility artefacts, a lack of quantitative tissue measurements, as well as overall lower image resolution and bone-soft tissue contrast compared to CT. The use of 3D MRI pulse sequences providing CLBC such as 3D-Bone could potentially offer complete clinical evaluation of bony morphology and soft tissues with a single MRI study for certain clinical indications, negating the need for ionizing radiation exposure from CT and reducing costs.

Patterns of injuries in sports groin: Review and pictorial essay

Sports-related groin injuries are prevalent in multidirectional sports and typically present with inguinal pain and localized tenderness. These injuries can be disabling, leading to missed practice and warranting prolonged absences from sports events, potentially compromising a professional athlete’s career. These injuries are difficult to diagnose due to the complex anatomy and pathophysiology. Imaging, particularly high-resolution magnetic resonance imaging, is excellent for evaluating cause, location, and severity of groin injuries. Understanding the anatomy of the groin and recognizing specific patterns of imaging findings is crucial for accurate diagnosis and targeted treatment planning.

The Impact of Diagnostic Imaging on Obstructive Sleep Apnea: Feedback from a Narrative Review

Obstructive Sleep Apnea is a prevalent sleep disorder characterized by repeated episodes of partial or complete upper airway obstruction during sleep, leading to disrupted sleep and associated comorbidities. Effective, traditional diagnostic methods, such as polysomnography, have limitations in providing comprehensive anatomical detail. Recent advancements in imaging technology have the potential to revolutionize the diagnosis and management of OSA, offering detailed insights into airway anatomy, function, and dynamics. This paper explores the latest innovations in imaging modalities, including high-resolution magnetic resonance imaging, functional MRI, three-dimensional airway reconstructions, and the integration of artificial intelligence algorithms for enhanced image analysis. We discuss the potential of these technologies to improve the precision of OSA diagnosis, tailor treatment strategies, and predict treatment outcomes. Moreover, we examine the challenges of implementing these advanced imaging techniques in clinical practice, such as cost, accessibility, and the need for validation in diverse patient populations. We also consider the ethical implications of widespread imaging, particularly regarding data security and patient privacy. The future of OSA management is poised for transformation as these imaging technologies promise to provide a more nuanced understanding of the disorder and facilitate personalized treatment approaches. This paper calls for continued research and collaboration across disciplines to ensure these innovations lead to improved patient care and outcomes in the field of sleep medicine.

Evaluation of Intensive Statins and Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors on Intracranial Artery Plaque Stability: A Prospective Single-Arm Study.

Intracranial atherosclerotic stenosis is a leading cause of ischemic stroke and recurrent events due to plaque instability. High-resolution magnetic resonance imaging identifies plaque enhancement as a key marker of instability. This study evaluated the efficacy of combined high-intensity statins and proprotein convertase subtilisin/kexin type 9 inhibitors in plaque stabilization. In this prospective, single-arm study, patients with acute stroke and intracranial atherosclerotic stroke in the M1 segment of the middle cerebral artery or basilar artery were enrolled. After 24 weeks of intensive statin and evolocumab therapy, high-resolution magnetic resonance imaging assessments of intracranial vessels were conducted at baseline and follow-up. The primary end point was the change in stenosis degree; secondary end points included changes in plaque enhancement (contrast ratio) and plaque burden. Thirty-six patients (median age, 58 years) participated. After therapy, stenosis decreased from 75.9% (interquartile range, 69.5%-84.8%) to 65.3% (interquartile range, 53.8%-75.0%; P<0.001). Contrast ratio grades and contrast volume decreased significantly (P<0.001), and lumen area increased (from 1.03 mm2 [interquartile range, 0.59-1.72 mm2] to 2.08 mm2 [interquartile range, 1.00-3.10 mm2]; P<0.001). No significant changes were observed in wall area, wall area index, or remodeling index. A notable correlation between the decrease in low-density lipoprotein cholesterol/apolipoprotein B ratio and reduction in contrast volume was observed. Combining proprotein convertase subtilisin/kexin type 9 inhibitors with high-intensity statins may improve plaque stability and reduce lumen stenosis in patients with intracranial atherosclerotic stenosis. Larger randomized controlled trials are needed to confirm these findings. URL: https://www.chictr.org.cn; Unique identifier: ChiCTR2200058029.

Category-biased patches encircle core domain-general regions in the human lateral prefrontal cortex.

The fine-grained functional organization of the human lateral prefrontal cortex (PFC) remains poorly understood. Previous fMRI studies delineated focal domain-general, or multiple-demand (MD), PFC areas that co-activate during diverse cognitively demanding tasks. While there is some evidence for category-selective (face and scene) patches, in human and non-human primate PFC, these have not been systematically assessed. Recent precision fMRI studies have also revealed sensory-biased PFC patches adjacent to MD regions. To investigate if this topographic arrangement extends to other domains, we analysed two independent fMRI datasets (n=449 and n=37) utilizing the high-resolution multimodal MRI approaches of the Human Connectome Project (HCP). Both datasets included cognitive control tasks and stimuli spanning different categories: faces, places, tools and body parts. Contrasting each stimulus category against the remaining ones revealed focal interdigitated patches of activity located adjacent to core MD regions. The results were robust, replicating across different executive tasks, experimental designs (block and event-related) and at the single subject level. Our results paint a refined view of the fine-grained functional organization of the PFC, revealing a recurring motif of interdigitated domain-specific and domain-general circuits. This organization offers new constraints for models of cognitive control, cortical specialization and development.

Amygdala Nuclei Atrophy in Cognitive Impairment and Dementia: Insights from High-Resolution Magnetic Resonance Imaging.

Background and Objectives: Cognitive impairment affects memory, reasoning, and problem-solving, with early detection being critical for effective management. The amygdala, a key structure in emotional processing and memory, may play a pivotal role in detecting cognitive decline. This study examines differences in amygdala nuclei volumes in patients with varying levels of cognitive performance to evaluate its potential as a biomarker. Material and methods: This cross-sectional study of 35 participants was conducted and classified into three groups: the normal (≥26), moderate (15-25), and low (≤14) cognitive performance groups based on the Montreal Cognitive Assessment (MoCA) scores. High-resolution magnetic resonance imaging at 3.0 T scanner was used to assess amygdala nuclei volumes. Results: Significant amygdala atrophy was observed in multiple amygdala nuclei across cognitive performance groups, with more pronounced changes in the low-performance group. The right hemisphere nuclei, including the lateral and basal nuclei, showed more significant differences, indicating their sensitivity to cognitive decline. Conclusions: This study highlights the potential of amygdala nuclei atrophy as a biomarker for cognitive impairment. Additional research with larger sample sizes and longitudinal designs is needed to confirm these findings and determine their diagnostic value.

Long COVID-19-related and non-COVID-19 postviral olfactory dysfunction a comparative MRI study focusing on the olfactory cleft and bulbs.

To compare the magnetic resonance imaging (MRI) features of the olfactory cleft (OC) and olfactory bulbs (OBs) in patients with long COVID-19-related (LCOD) and non-COVID-19 postviral olfactory dysfunction (NCPVOD) to explore mechanisms underlying persistent olfactory dysfunction. This retrospective analysis included patients diagnosed with LCOD or NCPVOD at the China-Japan Friendship Hospital between February 2023 and July 2024. All patients underwent olfactory psychophysical testing (Sniffin' Sticks), a visual analogue scale (VAS) for olfactory function, and high-resolution MRI scans of the olfactory pathway. MRI features, including OC opacity, OB morphology, OB volume, and olfactory sulcus depth, were compared between groups. Correlations between MRI findings and olfactory test scores were assessed. Seventy patients were included (35 LCOD, 35 NCPVOD). LCOD patients had significantly higher OC opacity scores than NCPVOD patients (p < 0.001). No significant differences were found in OB morphology, abnormal OB signals, OB volume reduction, or distances between OBs and surrounding structures (p > 0.05). LCOD patients had significantly greater right olfactory sulcus depth than NCPVOD patients (p = 0.026), with negative correlation to age (r = -0.25, p = 0.04). OB volumes positively correlated with TDI and VAS scores. LCOD patients exhibited greater OC opacity than NCPVOD patients, suggesting OC inflammation may contribute to persistent olfactory dysfunction. Treating inflammation in the OC could improve long-term olfactory outcomes. OB volume reduction was common in both groups.