Using Deep-Learning-Based Artificial Intelligence Technique to Automatically Evaluate the Collateral Status of Multiphase CTA in Acute Ischemic Stroke.

BACKGROUND: Collateral status is an important predictor for the outcome of acute ischemic stroke with large vessel occlusion. Multiphase computed-tomography angiography (mCTA) is useful to evaluate the collateral status, but visual evaluation of this examination is time-consuming. This study aims to use an artificial intelligence (AI) technique to develop an automatic AI prediction model for the collateral status of mCTA. METHODS: This retrospective study enrolled subjects with acute ischemic stroke receiving endovascular thrombectomy between January 2015 and June 2020 in a tertiary referral hospital. The demographic data and images of mCTA were collected. The collateral status of all mCTA was visually evaluated. Images at the basal ganglion and supraganglion levels of mCTA were selected to produce AI models using the convolutional neural network (CNN) technique to automatically predict the collateral status of mCTA. RESULTS: A total of 82 subjects were enrolled. There were 57 cases randomly selected for the training group and 25 cases for the validation group. In the training group, there were 40 cases with a positive collateral result (good or intermediate) and 17 cases with a negative collateral result (poor). In the validation group, there were 21 cases with a positive collateral result and 4 cases with a negative collateral result. During training for the CNN prediction model, the accuracy of the training group could reach 0.999 ± 0.015, whereas the prediction model had a performance of 0.746 ± 0.008 accuracy on the validation group. The area under the ROC curve was 0.7. CONCLUSIONS: This study suggests that the application of the AI model derived from mCTA images to automatically evaluate the collateral status is feasible.

Percutaneous transluminal angioplasty and stenting of post-irradiated stenosis of subclavian artery.

BACKGROUND/PURPOSE: The therapeutic efficacy of percutaneous transluminal angioplasty and stenting (PTAS) of post-irradiated stenosis of subclavian artery (PISSA) was not well clarified. This retrospective study was designed to evaluate the technical safety and outcome of the patients of severe symptomatic PISSA accepted PTAS. METHODS: Between 2000 and 2019, 16 cases with 17 lesions of symptomatic and medically refractory PISSA accepted PTAS were included. We evaluated their technical success, peri-procedural complications and diffusion-weight imaging (DWI) of brain magnetic resonance imaging (MRI), results of symptom relief, and long-term stent patency. RESULTS: The stenosis of the 17 stenotic lesions were 81.2 ± 11.1%. The most common symptom of the 16 patients was dizziness (14/16, 87.5%). All successfully accepted PTAS without neurological complication and had symptom relief after PTAS (17/17, 100%). Of the 12 patients accepted pre-procedural and early post-procedural MRI follow-up, 2 patients had an asymptomatic tiny acute embolic infarct in the territory of vertebrobasilar system. In a 51.9 ± 54.9 months follow-up, all patients had no severe restenosis and no recurrent vertebrobasilar ischemic symptoms. CONCLUSION: For patients with PISSA and medically refractory ischemic symptoms, PTAS can be an effective alternative management.

A practical biphasic contrast media injection protocol strongly enhances the aorta and pulmonary artery simultaneously using a single CT angiography scan.

BACKGROUND: Enhancement profiles of the pulmonary artery (PA) and aorta differ when using computed tomography (CT) angiography. Our aim was to determine the optimal CT protocol for a one-time CT scan that assesses both blood vessels. METHODS: We prospectively enrolled 101 cases of CT angiography in patients with suspected pulmonary embolism or aortic dissection from our center between 2018 and 2020. We also retrospectively collected the data of 40 patients who underwent traditional two-time CT scans between 2015 and 2018. Patients were divided into four groups: test bolus (TB) I, TB II, bolus-tracking (BT) I, and BT II. The enhancement of the PA and aorta, and the radiation doses used in the four groups were collected. Those who underwent two-time scans were classified into the traditional PA or aorta scan groups. Data were compared between the BT and traditional groups. RESULTS: The aortic enhancement was highest in BT II (294.78 ± 64.48 HU) followed BT I (285.18 ± 64.99 HU), TB II (186.58 ± 57.53 HU), and TB I (173.62 ± 69.70 HU). The radiation dose used was lowest in BT I (11.85 ± 5.55 mSv) and BT II (9.07 ± 3.44 mSv) compared with that used in the traditional groups (20.07 ± 7.78 mSv) and accounted for half of the traditional group (45.17-59.02%). The aortic enhancement was also highest in BT II (294.78 ± 64.48 HU) followed by BT I (285.18 ± 64.99 HU) when compared with that in the traditional aorta scan group (234.95 ± 94.18 HU). CONCLUSION: Our CT protocol with a BT technique allows for a lower radiation dose and better image quality of the PA and aorta than those obtained using traditional CT scans. TRIAL REGISTRATION: NCT04832633, retrospectively registered in April 2021 to the clinical trial registry.

Angioplasty and stenting for symptomatic stenosis of the left subclavian artery complicated with aortic dissection.

BACKGROUND: Aortic dissection is a rare but severe complication of percutaneous transluminal angioplasty and stenting (PTAS) for stenosis of the subclavian artery (SA). This retrospective study was designed to evaluate the risk factors and outcomes of patients with severe stenosis of the SA who underwent PTAS complicated by aortic dissection. METHODS: Between 1999 and 2018, 169 cases of severe symptomatic stenosis of the SA underwent PTAS at our institute. Of them, six cases complicated by aortic dissection were included in this study. We evaluated the demographic features, technical factors of PTAS, and clinical outcomes in these six patients. RESULTS: Aortic dissection occurred in 5.3% (6/113) of all left SA stenting cases but in none of the right SA stenting cases. All patients had hypertension and a high severity of SA stenosis (85.0 ± 13.0%, 60%-95%). Five of the six patients received balloon-expandable stents (83.3%). All patients had spontaneous resolution of the aortic dissection with conservative treatment. In a 63.33 ± 33.07 (7-118) month follow-up, five of the six patients (83.3%) had long-term symptom relief and stent patency. CONCLUSION: Aortic dissection occurred in patients who underwent PTAS for severe stenosis of the left SA, mainly with balloon-expandable stents. We suggest using self-expandable stents and angioplasty with an undersized balloon during PTAS for severe stenosis of the left proximal SA to prevent aortic dissection.

Mesenteric lymphadenopathy is a key to diagnosis of radiologically challenging pulmonary lymphoma.

Extranodal marginal zone B-cell lymphoma (EMZBL), previously known as mucosa-associated lymphoid tissue lymphoma, is the most common type of marginal zone B-cell lymphomas. Primary pulmonary lymphomas only constitute 0.5% of primary lung cancer, but 90% of these are EMZBLs. Primary pulmonary lymphomas share similar imaging features with secondary pulmonary lymphomas. Imaging diagnosis is challenging because many benign and other malignant lung lesions can display similar features. Here, we demonstrate a 70-year-old male case with lung tumors and only mesenteric lymphadenopathy, which was eventually diagnosed as advanced pulmonary EMZBL with involvement of the mesenteric lymph nodes and bone marrow. Pulmonary masses have a wide differential diagnosis, but concurrent isolated mesenteric lymphadenopathy might be a radiological clue to pulmonary lymphoma. KEY POINTS: Concurrent isolated mesenteric lymphadenopathy might be a radiological clue to pulmonary lymphoma. For nonspecific lung tumors, additional abdominal computed tomography (CT) scan might be helpful for diagnosis of possible lymphoma.

Oblique views of chest radiography from a designed rotation angle recommendation increase the contrast ratio between obscured lesions and surrounding structures.

BACKGROUND: Chest radiography (CXR) is the main tool used to detect pulmonary nodules. Lateral views of CXR are less effective and the aim of our study was to develop a rotation angle recommendation model to obtain the best oblique CXR with significantly increased contrast between lesions and surrounding normal structures in order to enhance the detection rate for potential obscured lesions on traditional posterior and anterior (PA) CXR. METHODS: A total of 140 subjects receiving low-dose lung computed tomography (CT) screening were enrolled from the health check-up database. An additional 14 cases with lung lesions on chest CT were included. Demography was also reviewed. Gross, left and right cardiothoracic ratios (CTR) were measured. All CT images were transformed to CXR to detect the best rotation angles and produce different views of CXR. Contrast ratio was calculated in the transformed CXR from CT with lesions. Comparison of contrast ratio among oblique, posterior-anterior and lateral views was performed. RESULTS: CXR shows smaller gross CTR and left CTR but larger heart width and thoracic width in men than in women. Correlation evaluation displays gross CTR, heart width and left CTR are positively correlated with age only for the women group. The most important factor for the best rotation angle is right CTR for left rotation angle and left CTR for right rotation angle. The contrast ratio of the lesion to surrounding structures is significantly better on the oblique views in the designed angles than that on the traditional views. CONCLUSION: CXR oblique views in the assigned angle from the 10-degree rotation angle recommendation are able to enhance contrast ratio between the possible obscured lesions and surrounding structures on CXR.

The Combination of Functional and Structural MRI Is a Potential Screening Tool in Alzheimer's Disease.

Introduction: This study aimed to survey the discrimination power of parameters from cerebrospinal fluid (CSF) biomarkers, fluorodeoxyglucose uptake on PET (FDG-PET), structural magnetic resonance imaging (MRI), and functional MRI in high- and low-risk subjects or in converters and stable subjects of normal and mild cognitive impairment (MCI) statuses. Methods: We used baseline resting-state functional MRI (rfMRI) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset to analyze functional networks and recorded subjects' characteristics and results of the CSF study, FDG-PET, and structural MRI from the ADNI website. All parameters were evaluated based on the between-group difference among normal (NC), MCI, and Alzheimer's disease (AD) groups. The parameters other than CSF results were included to study the difference between high- and low-AD-risk subjects in NC or MCI groups, based on CSF results. On the basis of two-year follow-up conditions, all parameters were compared between stable subjects and converters in NC and MCI. Results: CSF biomarkers, FDG-PET, structural MRI, and functional MRI are all able to differentiate AD from MCI or NC but not between MCI and NC. As compared with low-AD-risk subjects, high-risk subjects present decreased FDG-PET in both MCI and NC groups but structural MRI change only in MCI status and rfMRI alteration only in NC status. As compared with stable subjects, converters have decreased FDG-PET, functional network changes, and structural changes in both MCI and NC groups. Conclusion: The combination of functional and structural MRI is a safer screening tool but with similar power as FDG-PET to reflect CSF change in the AD pathological process and to identify high-risk subjects and converters in NC and MCI.

Does biopsy needle traversing through central portion of lesion increase the risk of hemoptysis during percutaneous transthoracic needle biopsy?

PURPOSE: To evaluate whether traversal through the central part of a pulmonary lesion by a biopsy needle, and other factors, increases the risk of hemoptysis in patients undergoing CT-guided percutaneous transthoracic needle biopsy (PTNB). MATERIALS AND METHODS: From July 2012 to November 2016, 227 patients undergoing 233 procedures were recruited as our study population. Patients were classified according to the occurrence of hemoptysis. Radiological assessments were performed by reviewing multiplanar reconstructed CT images. Other factors complicating PTNB-related hemoptysis were classified into (1) patient-related variables: age, gender, presence of emphysema; (2) lesion-related variables: size, location, distance to pleura, characteristics, presence of and degree of enhancement, histopathology of biopsy results; and (3) procedure-related variables: lesion depth, patient's body position. RESULTS: Twenty-two cases (9.4%) experienced hemoptysis. Univariate analysis revealed that subsolid lesions (p = 0.031) and lesion depth > 1 cm (p = 0.049) were risk factors. Traversal through the central part of the lesion by the biopsy needle was not a risk factor. CONCLUSION: Traversal through the central part of the lesion by the biopsy needle is not a risk factor of PTNB-related hemoptysis, but subsolid lesions and lesion depth > 1 cm increase the risk of hemoptysis.