Feng Gao

Purpose: To explore the feasibility of phase contrast (PC) MRI and three‐dimensional pulsed arterial spin labelling (3D PASL)‐MRI in assessing cerebrovascular blood flow changes after surgical revascularization in patients with moyamoya disease (MMD). Methods: This study was a prospective study and comprised two sections. In the first section, 43 patients with MMD who never underwent any revascularization surgery and 19 healthy control volunteers were enrolled. In the second section, 51 patients with MMD who underwent revascularization surgery were included. PC‐MRI and 3D PASL‐MRI were performed. The average blood flow in the internal carotid (ICA), basilar (BA), superficial temporal (STA) arteries and cerebral blood flow (CBF) were compared between the MMD patients and control volunteers (first section) as well as before and after surgery (second section). Then, MMD patients were divided into haemorrhage and non‐haemorrhage subgroups and the average blood flow and CBF before and after surgery were compared between the subgroups. Results: The average flow in the ICA, BA, STA was lower in the MMD patients than in the healthy control group ( p = 0.000, p = 0.001, p = 0.001). The CBF of the seven clusters was higher in the healthy controls than in the MMD patients' groups. The average flow in the ICA, BA and STA was increased in MMD patients after combined surgery ( p = 0.000, p = 0.002, p = 0.000). Fifteen clusters of elevated CBF and one of reduced CBF were postoperatively evident. Eight clusters of elevated CBF were compared with the preoperative status in the patients without haemorrhage. In the haemorrhage group, postoperative CBF did not significantly change after combined surgery ( p > 0.05). Conclusion: Both 3D PASL‐MRI and PC‐MRI can noninvasively evaluate CBF changes in patients with MMD after surgery. The CBF of the cerebral was significantly improved after surgery. Moreover, the improvement of CBF was more obvious in patients with non‐hemorrhagic rather than hemorrhagic MMD.

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We aimed to compare the performance and interobserver agreement of radiologists manually segmenting images or those assisted by automatic segmentation. We further aimed to reduce interobserver variability and improve the consistency of radiomics features. This retrospective study included 327 patients diagnosed with prostate cancer from September 2016 to June 2018; images from 228 patients were used for automatic segmentation construction, and images from the remaining 99 were used for testing. First, four radiologists with varying experience levels retrospectively segmented 99 axial prostate images manually using T2-weighted fat-suppressed magnetic resonance imaging. Automatic segmentation was performed after 2 weeks. The Pyradiomics software package v3.1.0 was used to extract the texture features. The Dice coefficient and intraclass correlation coefficient (ICC) were used to evaluate segmentation performance and the interobserver consistency of prostate radiomics. The Wilcoxon rank sum test was used to compare the paired samples, with the significance level set at p < 0.05. The Dice coefficient was used to accurately measure the spatial overlap of manually delineated images. In all the 99 prostate segmentation result columns, the manual and automatic segmentation results of the senior group were significantly better than those of the junior group (p < 0.05). Automatic segmentation was more consistent than manual segmentation (p < 0.05), and the average ICC reached >0.85. The automatic segmentation annotation performance of junior radiologists was similar to that of senior radiologists performing manual segmentation. The ICC of radiomics features increased to excellent consistency (0.925 [0.888~0.950]). Automatic segmentation annotation provided better results than manual segmentation by radiologists. Our findings indicate that automatic segmentation annotation helps reduce variability in the perception and interpretation between radiologists with different experience levels and ensures the stability of radiomics features.

Introduction: Moyamoya disease (MMD) is associated with a risk of postoperative cerebral hyperperfusion syndrome (CHS) after revascularization surgery. This study aimed to explore the feasibility of using three-dimensional pulsed arterial spin labeling (3D PASL) and phase contrast (PC) magnetic resonance imaging (MRI) for predicting CHS occurrence in patients with MMD before revascularization surgery.Methods: Overall, 191 adult patients (207 hemispheres) with MMD who underwent combined revascularization surgery were included in this study. Preoperative 3D PASL-MRI and PC-MRI were performed before surgery. The PASL-MRI data were analyzed using SPM12. Patient clinical information, average flow, and preoperative cerebral blood flow (CBF) were compared between the non-CHS and CHS groups.Results: Among the patients, 45 (21.74%) developed CHS after revascularization surgery. No significant differences were noted in age, sex, clinical symptoms, hypertension, diabetes, surgical side, or history of revascularization surgery between the non-CHS and CHS groups. However, the average flow in the superficial temporal artery was significantly lower in the CHS group than in the non-CHS group (p < 0.05). Furthermore, 11 clusters of preoperative CBF values were significantly greater in the CHS group than in the non-CHS group [p < 0.05, false discovery rate (FDR) corrected]. A significant correlation was also observed between the preoperative time-to-flight MR angiography (MRA) scores and CBF values in patients with MMD (p < 0.05).Conclusion: Compare patients with lower preoperative CBF and higher preoperative average flow in the STA, patients with higher preoperative CBF and lower preoperative average flow in the STA are more likely to develop postoperative CHS Preoperative PASL-MRI and PC-MRI examinations may help to screen patients at high risk of developing CHS after revascularization surgery.

Objective: This study aimed to investigate the feasibility of preoperative intravoxel incoherent motion (IVIM) MRI for the screening of high-risk patients with moyamoya disease (MMD) who may develop postoperative cerebral hyperperfusion syndrome (CHS).Methods: This study composed of two parts. In the first part 24 MMD patients and 24 control volunteers were enrolled. IVIM-MRI was performed. The relative pseudo-diffusion coefficient, perfusion fraction, apparent diffusion coefficient, and diffusion coefficient (rD*, rf, rADC, and rD) values of the IVIM sequence were compared according to hemispheres between MMD patient and healthy control groups. In the second part, 98 adult patients (124 operated hemispheres) with MMD who underwent surgery were included. Preoperative IVIM-MRI was performed. The rD*, rf, rADC, rD, and rfD* values of the IVIM sequence were calculated and analyzed. Operated hemispheres were divided into CHS and non-CHS groups. Patients’ age, sex, Matsushima type, Suzuki stage, and IVIM-MRI examination results were compared between CHS and non-CHS groups.Results: Only the rf value was significantly higher in the healthy control group than in the MMD group (P < 0.05). Out of 124 operated hemispheres, 27 were assigned to the CHS group. Patients with clinical presentation of Matsushima types I–V were more likely to develop CHS after surgery (P < 0.05). The rf values of the ipsilateral hemisphere were significantly higher in the CHS group than in the non-CHS group (P < 0.05). The rfD* values of the ACA and MCA supply areas of the ipsilateral hemisphere were significantly higher in the CHS group than in the non-CHS group (P < 0.05). Only the rf value of the anterior cerebral artery supply area in the contralateral hemisphere was higher in the CHS group than in the non-CHS group (P < 0.05). The rf values of the middle and posterior cerebral artery supply areas and the rD, rD*, and rADC values of the both hemispheres were not significantly different between the CHS and non-CHS groups (P > 0.05).Conclusion: Preoperative non-invasive IVIM-MRI analysis, particularly the f-value of the ipsilateral hemisphere, may be helpful in predicting CHS in adult patients with MMD after surgery. MMD patients with ischemic onset symptoms are more likely to develop CHS after surgery.

Objective:To explore the computed tomography (CT) characteristics of small lung nodules and improve the diagnosis of pulmonary ground-glass nodules less than 10 mm in size.Methods:We retrospectively analyzed CT images of 161 pulmonary nodules (less than 10 mm in size) with spiculation, lobulation, vacuoles and pleural indentation and compared these images with pathological results or follow-up CT images. The relationships between the ground-glass nodules (GGNs) and blood vessels were observed. The GGN-vessel relationship were divided into four type, Type I (pass-by), Type II (pass-through), Type III (distorted/dilated), Type IV (complicated). The vessels traveling through a GGN were divided into three categories, category A (arteries), category B (veins), category C (arteries and veins).Results:One hundred sixty-one GGNs were divided into 3 groups(benign group, pre-invasive group and adenocarcinoma group) according to their pathological diagnosis. Significant differences in density of nodules were obser...

This study aimed to explore the value of contrast-enhanced computed tomography (CT) scans in the differential diagnosis of atypical adenomatous hyperplasia, adenocarcinoma in situ, minimal invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IAC), which manifested as ground glass nodules (GGNs) or mixed GGNs. Unenhanced and contrast-enhanced presurgical CT images of 136 cases of GGNs were compared. The nodules were diagnosed based on their solid portions and maximum dimensions, and the findings obtained using both contrast-enhanced and unenhanced CT images were analyzed in corroboration with the pathological diagnosis. Most (53/56) preinvasive nodules showed increased mean CT values after contrast administration. In the MIA group, after contrast administration, enlargements of the solid portions were seen in 48 nodules (48/60), and the elevation of the mean CT value was observed in 12 nodules (12/60). The vast majority of IAC nodules (29/30) showed enlargement of the solid portions after contrast administration. Moreover, for group differences, findings obtained using this approach statistically match the pathological findings. Contrast-enhanced CT scans are more useful than unenhanced CT scans for the diagnosis of GGNs, especially for pure GGNs, before surgery.

While conventional ultrasound and laboratory testing can differentiate most thyroid conditions and malignancies, spectral dual-energy computed tomography (DECT) provides molecular data potentially useful in differential diagnosis of small, complex, and partially obscured hemorrhaged nodules with recent bleeding. To demonstrate that Gemstone Spectral Imaging (GSI) analysis of DECT data differentiates challenging benign thyroid nodule conditions in patients with intranodular hemorrhages. A retrospective study was conducted of 30 intranodular hemorrhage patients from 2010 to 2013, including 18 that underwent surgery and provided thyroid tissues for prospective histological analysis. Iodine and water content were determined in patient CT scans and ex vivo tissue specimen scans by reconstruction of raw CT data at 65 keV (optimal contrast). Slope of spectral curve (λ _HU), effective atomic number (Z _eff), and final pathological diagnosis were recorded. Iodine content, water content, Z _eff, and λ _HU significantly varied by region (intranodular hemorrhage, solid thyroid nodule, and adjacent margins) in patients and tissue specimens (P < 0.05). Intranodular hemorrhage exhibited elevated water concentrations (~1100 mg/mL), suggesting a practical threshold of 1075 mg/mL for differentiating intra-plaque hemorrhage and solid nodular regions. Spectral CT provided diagnostic information in 14 thyroid adenomas and four goiters (histologically confirmed in donor specimens), and eight thyroid adenomas and four nodular goiters based on clinical diagnosis. Diagnostically useful regional characteristic of intranodular hemorrhage in the thyroid was visualized via spectral CT employing material decomposition, potentially yielding additional molecular data about complex lesion characteristics no apparent in conventional imaging or laboratory methods.