BMC Medical Imaging最新文献

Background: This study investigated the functional connectivity (FC) patterns of cerebellar components of seven intrinsic connectivity networks (ICNs) across different stages of Alzheimer's disease (AD).

Methods: FC between each cerebellar seed region corresponding to one of the seven ICNs and 91 cerebral regions of interest (ROI) corresponding to the cortical parcels defined by Harvard-Oxford atlas was calculated for individuals with clinically diagnosed probable AD dementia (n = 21), mild cognitive impairment (n = 34), and subjective cognitive decline (n = 33). Group differences were assessed using ANOVA with false discovery rate (FDR) correction for multiple ROIs (p_FDR-corr<0.05).

Results: Significant alterations were observed in FC between the frontoparietal network (FPN) and the left superior frontal gyrus (SFG), as well as between the limbic network (LN) and the right superior lateral occipital cortex (sLOC) and temporo-occipital middle temporal gyrus (toMTG). Specifically, FPN-SFG connectivity decreased at the dementia stage, while LN-toMTG and LN-sLOC connectivity decreased during the prodromal stage but increased in the dementia stage.

Conclusions: These results indicate the presence of both decreases and increases in cerebellar-cortical FC across different stages of AD. A detailed examination of cerebellar involvement, an aspect often underexplored in AD research, may be crucial for understanding the neural mechanisms underlying disease progression.

Aim: Thromboangiitis Obliterans (TAO), or Buerger's disease, affects peripheral vessels and is linked to smoking. This study using diffusion tensor imaging (DTI) tractography examines brain microstructural changes in TAO patients compared to healthy smokers and Normal controls, aiming to reveal neurological implications beyond the known peripheral effects.

Methods: The case-control study involved 50 participants aged 27-56 in northeastern Iran, including TAO patients, healthy smokers, and non-smoking controls. MRI scans with DTI were conducted to assess 21 brain tracts for fractional anisotropy (FA) and apparent diffusion coefficient (ADC).

Results: Significant differences in brain tract integrity were observed among the groups. TAO patients showed lower FA values in the minor forceps compared to healthy smokers, while smokers had higher FA values than non-smoking controls. ADC values were notably higher in TAO patients across several tracts, including the minor and major forceps, corticospinal tracts, fornix tracts, and arcuate fasciculus, compared to both healthy smokers and controls.

Conclusion: The study highlights distinct brain tract alterations in TAO patients and suggests potential neurological consequences associated with the disease and smoking habits. DTI proves valuable in understanding microstructural brain changes and could serve as a diagnostic tool for evaluating smoking-related neurologic complications, providing insights into TAO's impact beyond peripheral vessels.

Clinical trial registration: N/A.

Objective: To develop and validate an automated, disc-level deep learning pipeline for quantitative measurement of anteroposterior (AP) thecal sac diameter on mid-sagittal lumbar T2-weighted MRI.

Materials and methods: In this retrospective study, 511 mid-sagittal lumbar T2 MRI examinations were included after screening 758 cases and applying predefined exclusions. The workflow combined YOLOv8 oriented bounding boxes (OBB) for disc-level localization and orientation estimation, homography-based ROI warping, Attention U-Net segmentation, and skeleton-based AP diameter computation in millimeters using DICOM pixel spacing. Validation was performed on internal (50) and external (50; RSNA 2024 lumbar dataset) cohorts with two radiologists providing the reference standard.

Result: Inter-reader agreement was excellent (ICC (2, 1) = 0.967; 711 paired measurements). Against the reader-mean reference, the pipeline achieved an overall MAE of 0.994 mm (711 disc-level measurements). Internal validation showed MAE 0.909 mm (357 measurements) and external validation MAE 1.079 mm (354 measurements). Severity-wise MAE remained ~ 1 mm (mild 0.930 mm; moderate 1.234 mm; severe 1.038 mm). Automatic disc-level labeling was performed, and OBB-derived orientation significantly improved AP measurement-line validity versus axis-aligned detection (acceptable lines 99.02% vs. 77.64%).

Conclusion: An orientation-aware YOLOv8-OBB + Attention U-Net pipeline enables automated, disc-level AP thecal sac diameter quantification on mid-sagittal lumbar MRI with ~ 1 mm error relative to expert reference, supporting standardized morphometric reporting and measurement-driven assessment of lumbar stenosis.

Objective: To evaluate the value of magnetic resonance imaging (MRI) in identifying the pathologic complete response (pCR) of patients with locally advanced rectal cancer (LARC) after neoadjuvant therapy (NAT).

Materials and methods: This retrospective study included 152 patients with LARC who underwent NAT followed by total mesorectal excision (TME) at our hospital between January 2019 and November 2024. The response to NAT was assessed using MRI. At first, the response was assessed according to MRI-based tumor regression grade (mrTRG), which was only on the basis of T2 weighted imaging (T2WI). Then, diffusion weighted imaging (DWI) was added to construct biparametric MRI-based tumor regression grade (BPmrTRG), followed by multiparametric MRI-based tumor regression grade (MPmrTRG) consisting of T2WI, DWI and contrast-enhanced T1-weighted imaging (CE-T1WI). The diagnostic efficacy of the three methods for identifying pCR was assessed by calculating the area under the receiver operating characteristic (ROC) curve (AUC), positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity. The DeLong test was used to compare the AUCs of different methods.

Results: Of the 152 patients, 27 (17.8%) were obtained pCR at surgical histopathological analysis. Among the three different MRI-based TRG methods, MPmrTRG archived the highest AUC of 0.891 (95% CI: 0.814-0.957) to identify pCR after NAT, followed by an AUC of 0.840 (95%CI: 0.745-0.916) for BPmrTRG and 0.729 (95% CI: 0.630-0.818) for mrTRG. Paired comparisons showed that AUC of MPmrTRG was higher than that of mrTRG with statistically significant after Bonferroni correction (p = 0.007), as well as the sensitivity (0.815 vs. 0.481, p = 0.008).

Conclusion: After adding DWI and CE-T1WI, the multiparametric MRI approach could improve diagnosis performance for identifying pCR after NAT in patients with LARC, which could facility clinicians' decision and patients' consultation for the watch and wait strategy to forgo the surgery and preserve the organ.

Background: Some patients after percutaneous coronary intervention (PCI) still have chest pain, accompanied by anxiety. Mental stress test (MST) can trigger myocardial ischemia in patients with anxiety. This study assessed the myocardial microcirculation of post-PCI patients with anxiety using mental stress dynamic CT myocardial perfusion imaging (CT-MPI).

Methods: Post-PCI patients with chest pain underwent CT-MPI with MST using a series of the standardized color word/arithmetic stressors, and divided into anxiety group and non-anxiety group according to the generalized anxiety disorder scale. Myocardial blood flow (MBF) and myocardial blood flow reserve (MFR) were analyzed, using a 17-segment model.

Results: Fifty-one patients with 867 segments were included for final analysis, including 26 patients with anxiety and 25 patients without anxiety. The anxiety group had a lower MBF in stent areas compared to non-stent areas after MST (P < 0.05), but this phenomenon was not observed in the non-anxiety group. Anxiety severity was negatively correlated with global MFR (r=-0.542, P = 0.004) and positively correlated with decreased global MBF value (r = 0.577, P = 0.012). Multivariate logistic regression analysis identified anxiety as an independent risk factor for MBF reduction after coronary stent implantation (OR = 5.54, 95%CI: 1.47-20.88, P = 0.011).

Conclusions: Anxiety is associated with myocardial microcirculation dysfunction (MMD) in post-PCI patient, particularly in areas supplied by stented arteries. Anxiety is a risk factor for MMD under mental stress in post-PCI patients.