Coronal Maximum Intensity Projection Research Articles

Peripheral Non-Contrast MR Angiography Using FBI: Scan Time and T2 Blurring Reduction with 2D Parallel Imaging.

Non-contrast magnetic resonance angiography (NC-MRA), including fresh blood imaging (FBI), is a suitable choice for evaluating patients with peripheral artery disease (PAD). We evaluated standard FBI (sFBI) and centric ky-kz FBI (cFBI) acquisitions, using 1D and 2D parallel imaging factors (PIFs) to assess the trade-off between scan time and image quality due to blurring. The bilateral legs of four volunteers (mean age 33 years, two females) were imaged in the coronal plane using a body array coil with a posterior spine coil. Two types of sFBI and cFBI sequences with 1D PIF factor 5 in the phase encode (PE) direction (in-plane) and 2D PIF 3 (PE) × 2 (slice encode (SE)) (in-plane, through-slice) were studied. Image quality was evaluated by a radiologist, the vessel's signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured, and major vessel width was measured on the coronal maximum intensity projection (MIP) and 80-degree MIP. Results showed significant time reductions from 184 to 206 s on average when using sFBI down to 98 to 162 s when using cFBI (p = 0.003). Similar SNRs (averaging 200 to 370 across all sequences and PIF) and CNRs (averaging 190 to 360) for all techniques (p > 0.08) were found. There was no significant difference in the image quality (averaging 4.0 to 4.5; p > 0.2) or vessel width (averaging 4.1 to 4.9 mm; p > 0.1) on coronal MIP due to sequence or PIF. However, vessel width measured using 80-degree MIP demonstrated a significantly wider vessel in cFBI (5.6 to 6.8 mm) compared to sFBI (4.5 to 4.7 mm) (p = 0.022), and in 1D (4.7 to 6.8 mm) compared to 2D (4.5 to 5.6 mm) (p < 0.05) PIF. This demonstrated a trade-off in T2 blurring between 1D and 2D PIF: 1D using a PIF of 5 shortened the acquisition window, resulting in sharper arterial blood vessels in coronal images but significant blur in the 80-degree MIP. Two-dimensional PIF for cFBI provided a good balance between shorter scan time (relative to sFBI) and good sharpness in both in- and through-plane, while no benefit of 2D PIF was seen for sFBI. In conclusion, this study demonstrated the usefulness of FBI-based techniques for peripheral artery imaging and underscored the need to strike a balance between scan time and image quality in different planes through the use of 2D parallel imaging.

Study on evaluation method of circular small shadow profusion in chest CT reconstruction images of pneumoconiosis

Objective: To select chest CT image patterns for the diagnosis of pneumoconiosis and establish a method for determining the profusion of circular small shadows in chest CT. Methods: In April 2021, 66 cases of occupational pneumoconiosis patients with digital radiography (DR) chest radiographs and chest CT imaging data with circular small shadow as the main manifestations were selected as the study objects. 1.5 mm and 5 mm chest CT axial images, 1 mm and 5 mm chest CT coronal multi-plane recombination (MPR) images, and 5 mm chest CT coronal maximum intensity projection (MIP) images were used to observe the different characteristics of pneumoconiosis patients, and were compared and analyzed with DR chest radiographs to establish the experimental chest CT standards. The consistency of the profusion results between the experimental chest CT standards and GBZ 70-2015 Diagnosis of Occupational Pneumoconiosis was verified. Results: All the 66 objects were male, including 33 cases of stage Ⅰ pneumoconiosis, 17 cases of stage Ⅱ pneumoconiosis and 16 cases of stage Ⅲ pneumoconiosis. By observing five chest CT images of 66 objects, we found that chest CT images of different modes could clearly display and identify abnormal images such as small circular shadow, large shadow, small shadow aggregation, honeycomb glass shadow, flake glass shadow, uniform low-profusion glass shadow, mesh glass shadow, cable shadow, linear shadow, subpleural spinous shadow, subpleural nodules, various kinds of emphysema and lung texture distortion and fracture. Small shadow aggregation was usually accompanied by the appearance of large shadow. The vascular shadows in 5 mm CT images had good ductility, and small nodules were easy to distinguish. The coronal MIP image of 5 mm chest CT used edge enhancement technology, which was prone to small shadow fusion and fibrotic shadow fusion. The coronal MPR image of 5 mm chest CT was highly consistent with the DR chest radiographs in terms of the integrity of film reading. GBZ 70-2015 standard was used to compare the profusion of DR chest radiographs and 5 mm chest CT coronal MPR images of 66 objects, and the consistency test Kappa=0.64. GBZ 70-2015 standard and experimental chest CT standard were used to compare the profusion results of DR chest radiographs and 5 mm chest CT coronal MPR images of 66 objects, respectively, and the consistency test Kappa=0.80, with high consistency. Conclusion: 5 mm coronal MPR image is suitable for chest CT imaging in the diagnosis of pneumoconiosis. Following the selection path and method of GBZ 70-2015 profusion criterion, the established experimental chest CT standard in determining the profusion of small circular shadows in 5 mm coronal MPR images of chest CT with pneumoconiosis has a high consistency with GBZ 70-2015 standard.

Thorax computed tomography (CTX) guided ground truth annotation of CHEST radiographs (CXR) for improved classification and detection of COVID-19.

Several data sets have been collected and various artificial intelligence models have been developed for COVID-19 classification and detection from both chest radiography (CXR) and thorax computed tomography (CTX) images. However, the pitfalls and shortcomings of these systems significantly limit their clinical use. In this respect, improving the weaknesses of advanced models can be very effective besides developing new ones. The inability to diagnose ground-glass opacities by conventional CXR has limited the use of this modality in the diagnostic work-up of COVID-19. In our study, we investigated whether we could increase the diagnostic efficiency by collecting a novel CXR data set, which contains pneumonic regions that are not visible to the experts and can only be annotated under CTX guidance. We develop an ensemble methodology of well-established deep CXR models for this new data set and develop a machine learning-based non-maximum suppression strategy to boost the performance for challenging CXR images. CTX and CXR images of 379 patients who applied to our hospital with suspected COVID-19 were evaluated with consensus by seven radiologists. Among these, CXR images of 161 patients who also have had a CTX examination on the same day or until the day before or after and whose CTX findings are compatible with COVID-19 pneumonia, are selected for annotating. CTX images are arranged in the main section passing through the anterior, middle, and posterior according to the sagittal plane with the reformed maximum intensity projection (MIP) method in the coronal plane. Based on the analysis of coronal MIP reconstructed CTX images, the regions corresponding to the pneumonia foci are annotated manually in CXR images. Radiologically classified posterior to anterior (PA) CXR of 218 patients with negative thorax CTX imaging were classified as COVID-19 pneumonia negative group. Accordingly, we have collected a new data set using anonymized CXR (JPEG) and CT (DICOM) images, where the PA CXRs contain pneumonic regions that are hidden or not easily recognized and annotated under CTX guidance. The reference finding was the presence of pneumonic infiltration consistent with COVID-19 on chest CTX examination. COVID-Net, a specially designed convolutional neural network, was used to detect cases of COVID-19 among CXRs. Diagnostic performances were evaluated by ROC analysis by applying six COVID-Net variants (COVIDNet-CXR3-A, -B, -C/COVIDNet-CXR4-A, -B, -C) to the defined data set and combining these models in various ways via ensemble strategies. Finally, a convex optimization strategy is carried out to find the outperforming weighted ensemble of individual models. The mean age of 161 patients with pneumonia was 49.31 ± 15.12, and the median age was 48 years. The mean age of 218 patients without signs of pneumonia in thorax CTX examination was 40.04 ± 14.46, and the median was 38. When working with different combinations of COVID-Net's six variants, the area under the curve (AUC) using the ensemble COVID-Net CXR 4A-4B-3C was .78, sensitivity 67%, specificity 95%; COVID-Net CXR 4a-3b-3c was .79, sensitivity 69% and specificity 94%. When diverse and complementary COVID-Net models are used together through an ensemble, it has been determined that the AUC values are close to other studies, and the specificity is significantly higher than other studies in the literature.

An artificial intelligence method using FDG PET to predict treatment outcome in diffuse large B cell lymphoma patients

Convolutional neural networks (CNNs) may improve response prediction in diffuse large B-cell lymphoma (DLBCL). The aim of this study was to investigate the feasibility of a CNN using maximum intensity projection (MIP) images from 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) baseline scans to predict the probability of time-to-progression (TTP) within 2 years and compare it with the International Prognostic Index (IPI), i.e. a clinically used score. 296 DLBCL 18F-FDG PET/CT baseline scans collected from a prospective clinical trial (HOVON-84) were analysed. Cross-validation was performed using coronal and sagittal MIPs. An external dataset (340 DLBCL patients) was used to validate the model. Association between the probabilities, metabolic tumour volume and Dmaxbulk was assessed. Probabilities for PET scans with synthetically removed tumors were also assessed. The CNN provided a 2-year TTP prediction with an area under the curve (AUC) of 0.74, outperforming the IPI-based model (AUC = 0.68). Furthermore, high probabilities (> 0.6) of the original MIPs were considerably decreased after removing the tumours (< 0.4, generally). These findings suggest that MIP-based CNNs are able to predict treatment outcome in DLBCL.

Total Anomalous Pulmonary Venous Return.

Supplemental material is available for this article.

18F-FDG PET Maximum-Intensity Projections and Artificial Intelligence: A Win-Win Combination to Easily Measure Prognostic Biomarkers in DLBCL Patients.

Total metabolic tumor volume (TMTV) and tumor dissemination (Dmax) calculated from baseline 18F-FDG PET/CT images are prognostic biomarkers in diffuse large B-cell lymphoma (DLBCL) patients. Yet, their automated calculation remains challenging. The purpose of this study was to investigate whether TMTV and Dmax features could be replaced by surrogate features automatically calculated using an artificial intelligence (AI) algorithm from only 2 maximum-intensity projections (MIPs) of the whole-body 18F-FDG PET images. Methods: Two cohorts of DLBCL patients from the REMARC (NCT01122472) and LNH073B (NCT00498043) trials were retrospectively analyzed. Experts delineated lymphoma lesions from the baseline whole-body 18F-FDG PET/CT images, from which TMTV and Dmax were measured. Coronal and sagittal MIP images and associated 2-dimensional reference lesion masks were calculated. An AI algorithm was trained on the REMARC MIP data to segment lymphoma regions. The AI algorithm was then used to estimate surrogate TMTV (sTMTV) and surrogate Dmax (sDmax) on both datasets. The ability of the original and surrogate TMTV and Dmax to stratify patients was compared. Results: Three hundred eighty-two patients (mean age ± SD, 62.1 y ± 13.4 y; 207 men) were evaluated. sTMTV was highly correlated with TMTV for REMARC and LNH073B datasets (Spearman r = 0.878 and 0.752, respectively), and so were sDmax and Dmax (r = 0.709 and 0.714, respectively). The hazard ratios for progression free survival of volume and MIP-based features derived using AI were similar, for example, TMTV: 11.24 (95% CI: 2.10-46.20), sTMTV: 11.81 (95% CI: 3.29-31.77), and Dmax: 9.0 (95% CI: 2.53-23.63), sDmax: 12.49 (95% CI: 3.42-34.50). Conclusion: Surrogate TMTV and Dmax calculated from only 2 PET MIP images are prognostic biomarkers in DLBCL patients and can be automatically estimated using an AI algorithm.

A Complication Hanging by a Thread

Question: A 75-year-old man presented with a 1-month history of mild abdominal pain and cramping, associated with weight loss (3 kg). He denied any nausea, vomiting, chills, diarrhea, or hematochezia. The patient reported no trauma. He had a history of ampullary adenocarcinoma treated with pancreaticoduodenectomy 2 years earlier. The postoperative course was marked by hemorrhagic shock owing to a splenic artery pseudoaneurysm that was successfully treated by trans-arterial embolization. On physical examination, the patient was afebrile and had normal vital signs. He had a slight tender abdomen on palpation. Blood tests revealed a C-reactive protein level of 20.2 mg/L (reference value, <3.5 mg/L) and a white blood cell count of 3670/mm3 with 87% neutrophils. Other laboratory tests were unremarkable. A contrast-enhanced computed tomography (CT) scan showed a status post embolization of the splenic artery with hyperattenuating embolic material (Figure A) and long thin hyperattenuating foreign bodies in the small bowel lumen (Figure B–D; the entire CT scan is provided as supplemental material) that were better assessed on a coronal maximum intensity projection view (Figure E). The small bowel wall was normal. There was no sign of bowel perforation, no fluid collection, and no sign of active or recent bleeding. The colon was normal. The pancreaticojejunal anastomosis was unremarkable. There was no evidence of tumor recurrence. What is the diagnosis? Look on page 55 for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. The pancreaticoduodenectomy was complicated with a pseudoaneurysm arising from the splenic artery (Figure F) that was successfully treated with transarterial embolization with steel wire coils. A postembolization CT scan showed complete occlusion of the lesion and the splenic artery (coronal view; Figure G). There was no bleeding recurrence, and the patient was discharged. The patient was regularly followed-up with a CT scan that showed no evidence of tumor recurrence and no modification of the embolization site. A multidisciplinary team recommended conservative management with no invasive procedure to remove the migrated coils. The patient spontaneously and painlessly evacuated the coils in stools 5 weeks after the diagnosis (Figure H). A contrast-enhanced CT scan performed 3 weeks later showed the evacuation of migrated coils, and the persistence of coils in the splenic artery (Figure I). The patient is currently asymptomatic and free from tumor recurrence. Complications of splenic artery embolization include splenic infarction (1%–2%), splenic abscesses, left pleural effusion (10%), or basal atelectasis (30%), and rarely portal thrombosis. Migration of coils is exceptional and has been described after embolization of splenic pseudoaneurysms owing to vascular coil erosion into the gastrointestinal tract.1Shah N.A. Akingboye A. Haldipur N. et al.Embolization coils migrating and being passed per rectum after embolization of a splenic artery pseudoaneurysm, "the migrating coil": a case report.Cardiovasc Intervent Radiol. 2007; 30: 1259-1262Crossref PubMed Scopus (36) Google Scholar, 2Tekola B.D. Arner D.M. Behm B.W. Coil migration after transarterial coil embolization of a splenic artery pseudoaneurysm.Case Rep Gastroenterol. 2013; 7: 487-491Crossref PubMed Scopus (21) Google Scholar, 3Takahashi T. Shimada K. Kobayashi N. et al.Migration of steel-wire coils into the stomach after transcatheter arterial embolization for a bleeding splenic artery pseudoaneurysm: report of a case.Surg Today. 2001; 31: 458-462Crossref PubMed Scopus (46) Google Scholar As previously reported, migration was a delayed complication (3 months to 10 years in the literature). Of note, several cases reported evidence of infection at the erosion site, which was not present here. Management depends on the extent of material migration and symptoms and ranges from conservative treatment to more invasive procedures (endoscopic or surgical retrieval). No evidence suggests that specific coils are more prone to secondary migration. eyJraWQiOiI4ZjUxYWNhY2IzYjhiNjNlNzFlYmIzYWFmYTU5NmZmYyIsImFsZyI6IlJTMjU2In0.eyJzdWIiOiIwMDVhZjJiODcwMzAzNjk2ZmI2YWIzMjUzYjdlYWQxOSIsImtpZCI6IjhmNTFhY2FjYjNiOGI2M2U3MWViYjNhYWZhNTk2ZmZjIiwiZXhwIjoxNjgwMjM3NDk5fQ.LS386lU7wuNg_A2l4X5T61IP2FppVGq2DNjFd7aTwKDD2CnGpQETIi90YGkob6isNUAcHjGC4yhMDhQNo1DG5HKu1dFwUcd02ku-3-ijbtwufokHYbR9GkgBLJJrKiVWexXPcCmjZ80L7FxHY7cNGxrNvpL2raueVLp6qDpzbURZecPBVy2dgcAXpt6jsm1aasdWat3eZkIIzv_GjPqtCeiF2xd_C5fCUMsrsLpgVJRc4TUlfE7LeeevSOcSauQrdo1mVy7_4gMzUgxnWKEuzCzZQJNc2cgIvMo0DQPGSs8o2SDa7TKbqSjnpikBuxPR43PNpPDaTpv5tnSCsdVXbQ Download .mp4 (6.04 MB) Help with .mp4 files Video

A novel use for routine CBCT imaging during radiotherapy to detect COVID-19

IntroductionThoracic CT is a useful tool in the early diagnosis of patients with COVID-19. Typical appearances include patchy ground glass shadowing. Thoracic radiotherapy uses daily cone beam CT imaging (CBCT) to check for changes in patient positioning and anatomy prior to treatment through a qualitative assessment of lung appearance by radiographers. Observation of changes related to COVID-19 infection during this process may facilitate earlier testing improving patient management and staff protection. MethodsA tool was developed to create overview reports for all CBCTs for each patient throughout their treatment. Reports contain coronal maximum intensity projection (MIP's) of all CBCTs and plots of lung density over time. A single therapeutic radiographer undertook a blinded off-line audit that reviewed 150 patient datasets for tool optimisation in which medical notes were compared to image findings. This cohort included 75 patients treated during the pandemic and 75 patients treated between 2014 and 2017. The process was repeated retrospectively on a subset of the 285 thoracic radiotherapy patients treated between January–June 2020 to assess the efficiency of the tool and process. ResultsThree patients in the n = 150 optimisation cohort had confirmed COVID-19 infections during their radiotherapy. Two of these were detected by the reported image assessment process. The third case was not detected on CBCT due to minimal density changes in the visible part of the lungs.Within the retrospective cohort four patients had confirmed COVID-19 based on RT-PCR tests, three of which were retrospectively detected by the reported process. ConclusionThe preliminary results indicate that the presence of COVID-19 can be detected on CBCT by therapeutic radiographers. Implications for practiceThis process has now been extended to clinical service with daily assessments of all thoracic CBCTs. Changes noted are referred for oncologist review.

Value of susceptibility-weighted imaging for the assessment of angle measurements reflecting hip morphology

Radiographs are the clinical first line imaging modality for evaluating hip morphology and pathology. MRI offers additional information and is the method of choice to evaluate soft tissue, bone marrow and preradiographic signs of osteoarthritis. Radiographs are used to measure the most morphometric parameters. The aim of this study was to compare susceptibility weighted MRI (SWMR) with radiographs to evaluate hip morphology. 40 Patients were examined with standard MR-sequences, coronal SWMR and radiographs in anteroposterior pelvic view. Coronal maximum intensity projection (MIP) images of both hips were automatically reconstructed on SWMR and T1weighted images. Sharp´s angle, Tönnis angle, lateral center–edge angle of Wiberg and caput-collum-diaphyseal angle were measured on coronal SWMR MIP-images, T1weighted MIP-images and radiographs. Measurements were compared by linear regression analysis and Bland-Altmann Plots, using radiographs as reference standard. Additionally, a ratio between the signal intensity of muscles and bone on SWMR and T1weighted MIP-images was calculated and compared between these two sequences. SWMR enables the reliable assessment of Sharp´s angle (SWMR: R2 = 0.80; T1weighted: R2 = 0.37), Tönnis angle (SWMR: R2 = 0.86; T1weighted: not measurable), lateral center–edge angle of Wiberg (SWMR: R2 = 0.88; T1weighted: R2 = 0.40) and caput-collum-diaphyseal angle (SWMR: R2 = 0.38; T1weighted: R2 = 0.18) compared to radiographs with a higher accuracy than conventional MR imaging. The ratio between the intensity of muscles and bone was significant higher on SWMR (2.00 and 2.02) than on T1weighted MIP-images (1.6 and 1.42; p < 0.001).

Vascular changes of the superior mesenteric artery (SMA): A new component of the hypovolemic shock complex (HSC)

PurposeTo assess the type and frequency of vascular changes in the superior mesenteric artery (SMA) associated with the hypovolemic shock complex (HSC). MethodsTwenty-six patients (14 males, 70.6 ± 11.2 years) meeting the criteria for hypovolemic shock complex in computed tomography were examined for the presence of angiographic signs of non-occlusive mesenteric ischemia (NOMI) in the SMA: the string of sausages sign and spasms of the arcades of mesenteric arteries on coronal maximum intensity projection images (MIP). Interrater agreement was assessed using weighted kappa (κ). ResultsVascular changes of the SMA were visible in almost all of the patients with HSC with a frequency of 88.5 %–96.2 %. Intraclass correlation coefficients indicated a substantial to almost perfect interrater agreement. ConclusionsUsing computed tomography, it is possible to reliably and reproducibly detect vascular changes in SMA known from angiography in the context of hypoperfusion. The pathological vascular changes also occur more frequently than other classic signs of a CT hypoperfusion complex. Since the qualitative assessment of the SMA requires only a small amount of time, it is suitable as a further criterion for the presence of the CT hypoperfusion complex.

The Vascular Supply to Human Brown Adipose Tissue

Brown adipose tissue (BAT) engages in non‐shivering thermogenesis in response to cold exposure. Several aspects of its function require significant arterial and venous supplies. For example, the arterial system delivers endocrine signaling molecules and metabolic substrates including glucose and non‐esterified fatty acids to both stimulate and fuel BAT thermogenesis. Heat produced from BAT is then presumed to transfer to the blood passing through the tissue to protect core body temperature in response to the initiating cold stimulus. However, whether human BAT contains such a vascular system is unknown. The purpose of this study was to characterize the arterial and venous supply to supraclavicular BAT. Six healthy subjects [4 men; age: 30.7 ± 5.8 yrs.; body mass index: 21.7 ± 3.5 kg/m2; total body fat % (dual‐energy x‐ray absorptiometry scan): 23.5 ± 6.2 %] underwent time‐of‐flight magnetic resonance angiography (MRA) of the arterial and venous systems and quantitative fat/water MR imaging (FWMRI) to identify BAT. Angiography images were reconstructed at 0.5×0.5×2.0 mm resolution. FWMRI was performed using a 21‐echo spoiled gradient‐echo sequence, with computation of the fat signal fraction using the manufacturer’s algorithms. FWMRI images were reconstructed at 1.0×1.0×4.0 mm resolution and then resized to match the resolution of the MRA data. The supraclavicular BAT depot was hand‐defined from the apex of the lung to its superior margin in the FWMRI images. Coronal, axial, and sagittal maximum intensity projections (MIPs) of the BAT regions were overlaid onto co‐registered MIPs of the arterial and venous angiograms. In five subjects, there was a single, tortuous branch of the second part of the subclavian artery that supplied the BAT depot; in the sixth subject there was insufficient conspicuity to trace this artery back to the subclavian artery. The arterial diameters ranged from 1.5–2.5 mm. In no case was the artery observed to pass completely through the supraclavicular BAT depot. In two subjects, there was a single 3.5 mm diameter vein returning from the head and passing through the medial portion of the BAT. In the other four subjects, there were 3–4 veins with 2–4 mm diameters that returned from the head and that passed through both the medial and lateral portions of the BAT depot. Individuals with the largest diameter arteries also tended to have the most extensive venous systems. These preliminary data suggest that MRA and FWMRI may be used to quantify the arterial and venous supplies of the human supraclavicular BAT depot. The extensive venous supply to BAT, coupled with the absence of arteries passing fully through this BAT depot, together suggest that the primary thermogenic role of the supraclavicular BAT depot is in rewarming blood returning from the head to the central circulation.Support or Funding InformationNIDDK/NIH R01‐DK‐105371, NCATS/NIH UL1‐TR000445

Labeling Vertebrae with Two-dimensional Reformations of Multidetector CT Images: An Adversarial Approach for Incorporating Prior Knowledge of Spine Anatomy.

To use and test a labeling algorithm that operates on two-dimensional reformations, rather than three-dimensional data to locate and identify vertebrae. The authors improved the Btrfly Net, a fully convolutional network architecture described by Sekuboyina et al, which works on sagittal and coronal maximum intensity projections (MIPs) and augmented it with two additional components: spine localization and adversarial a priori learning. Furthermore, two variants of adversarial training schemes that incorporated the anatomic a priori knowledge into the Btrfly Net were explored. The superiority of the proposed approach for labeling vertebrae on three datasets was investigated: a public benchmarking dataset of 302 CT scans and two in-house datasets with a total of 238 CT scans. The Wilcoxon signed rank test was employed to compute the statistical significance of the improvement in performance observed with various architectural components in the authors' approach. On the public dataset, the authors' approach using the described Btrfly Net with energy-based prior encoding (Btrflype-eb) network performed as well as current state-of-the-art methods, achieving a statistically significant (P < .001) vertebrae identification rate of 88.5% ± 0.2 (standard deviation) and localization distances of less than 7 mm. On the in-house datasets that had a higher interscan data variability, an identification rate of 85.1% ± 1.2 was obtained. An identification performance comparable to existing three-dimensional approaches was achieved when labeling vertebrae on two-dimensional MIPs. The performance was further improved using the proposed adversarial training regimen that effectively enforced local spine a priori knowledge during training. Spine localization increased the generalizability of our approach by homogenizing the content in the MIPs.Supplemental material is available for this article.© RSNA, 2020.

Automatic gallbladder segmentation using combined 2D and 3D shape features to perform volumetric analysis in native and secretin-enhanced MRCP sequences.

We aimed to develop the first fully automated 3D gallbladder segmentation approach to perform volumetric analysis in volume data of magnetic resonance (MR) cholangiopancreatography (MRCP) sequences. Volumetric gallbladder analysis is performed for non-contrast-enhanced and secretin-enhanced MRCP sequences. Native and secretin-enhanced MRCP volume data were produced with a 1.5-T MR system. Images of coronal maximum intensity projections (MIP) are used to automatically compute 2D characteristic shape features of the gallbladder in the MIP images. A gallbladder shape space is generated to derive 3D gallbladder shape features, which are then combined with 2D gallbladder shape features in a support vector machine approach to detect gallbladder regions in MRCP volume data. A region-based level set approach is used for fine segmentation. Volumetric analysis is performed for both sequences to calculate gallbladder volume differences between both sequences. The approach presented achieves segmentation results with mean Dice coefficients of 0.917 in non-contrast-enhanced sequences and 0.904 in secretin-enhanced sequences. This is the first approach developed to detect and segment gallbladders in MR-based volume data automatically in both sequences. It can be used to perform gallbladder volume determination in epidemiological studies and to detect abnormal gallbladder volumes or shapes. The positive volume differences between both sequences may indicate the quantity of the pancreatobiliary reflux.

Detection of Renal Stones on Portal Venous Phase CT: Comparison of Thin Axial and Coronal Maximum-Intensity-Projection Images.

The objective of our study was to determine the sensitivity of thin axial and coronal maximum-intensity-projection (MIP) images for the detection of renal stones on contrast-enhanced CT performed in the portal venous phase. This retrospective study included 72 patients, 59 of whom had at least one renal stone, who underwent unenhanced CT immediately followed by contrast-enhanced CT in the portal venous phase. Two abdominal imaging fellowship-trained radiologists independently recorded the number of stones on both thin (1-1.50 mm) axial and 5-mm coronal MIP images in the portal venous phase. The reference standard was determined by consensus review of the thin axial unenhanced images. Reviewer sensitivity was calculated and categorized by stone diameter. One hundred forty-eight stones were present; the mean number of stones per patient was 2.5 (SD, 2.7). The mean stone size was 2.5 mm (SD, 2.7). The sensitivity of thin axial images was 89.9%, 99.0%, and 100.0% for reviewer 1 and 83.1%, 98.0%, and 100.0% for reviewer 2 for all stones, stones ≥ 2 mm, and stones ≥ 3 mm, respectively. The sensitivity of coronal MIP images was 86.5%, 96.2%, and 100.0% for reviewer 1 and 79.0%, 91.4%, and 96.6% for reviewer 2 for all stones, stones ≥ 2 mm, and stones ≥ 3 mm, respectively. Thin axial images are highly sensitive for the detection of renal stones ≥ 2 mm on portal venous phase CT. Coronal MIP images do not improve renal stone detection over thin axial images.

Hypervascularity Predicts Complete Pathologic Response to Chemotherapy and Late Outcomes in Breast Cancer

BackgroundOur objective was to investigate the relationship between asymmetric increase in breast vascularity (AIBV) and pathologic profiles of breast cancer. We also addressed the prognostic performance of AIBV and of vascular maps reduction after neoadjuvant chemotherapy (NAC) in predicting pathologic complete response (pCR) at surgery and outcome at follow-up. Materials and MethodsTwo hundred nineteen patients with unilateral locally advanced breast cancer (LABC) underwent magnetic resonance imaging before and after NAC. Axial, sagittal, and coronal maximum intensity projections were obtained in a subjective comparative evaluation. Asymmetrical versus symmetrical breast vascularity was defined through number of vessels, diameter, and signal intensity. Kaplan-Meier methodology was employed for late survival (31.4 ± 18 months follow-up). ResultsAIBV ipsilateral to LABC occurred in 62.5% (P < .001). AIBV was significantly associated with invasive ductal carcinoma, G3, triple-negative, HER2+, and hybrid phenotypes (P < .001). pCR was more frequent among patients with AIBV (24%) (P = .001). After NAC, the vascular map was significantly reduced, particularly in patients with pCR (P < .001). At follow-up, the recurrence rate was 22% (6.1% mortality). AIBV after NAC was associated with worse late survival (P = .036). A trend towards worse late survival existed among patients with AIBV before NAC. We did not observe statistically different survival according to the variation of vascularity after NAC. ConclusionLABC with ipsilateral AIBV before NAC is associated with more aggressive pathologic profiles. Nonetheless, it is more sensitive to NAC and shows a higher frequency of pCR. The persistence of AIBV after NAC entails a worse late prognosis and should prompt more aggressive therapeutic strategies.

Bilateral pulmonary artery aneurysm in Behcet's disease

, et al., Bilateral pulmo .1016/j.injr.2015.02.005 Investigatory reports were haemoglobin 11.5 g/dl, Erythrocyte Sediment Ratio (ESR) 87 mm/h, C reactive protein (CRP) 20.79 mg/L and serum creatinine 0.41 mg/dl. A diagnosis of Behcet's disease (BD) was made and he was treated with prednisolone (10mg/day) and azathioprine (50mg/day). There was initial clinical improvement but subsequently he developed recurrent haemoptysiswhile hewas still on azathioprine and prednisolone. CT Pulmonary angiographywas done. Axial and coronal oblique MIP (Maximum Intensity Projections) images showed aneurysmal dilatation of the descending

Distance to thrombus in acute middle cerebral artery occlusion: a predictor of outcome after intravenous thrombolysis for acute ischemic stroke.

In patients with acute middle cerebral artery (MCA) stroke, therapeutic decisions are influenced by the location of the occlusion. This study aimed to analyze clinical outcomes in patients with acute ischemic MCA stroke treated with systemic intravenous thrombolysis (IVT) using recombinant tissue plasminogen activator, according to the location of the occlusion. Of 621 patients screened, 136 with acute stroke and MCA occlusion confirmed by CT angiography were retrospectively included in this study. The distance from the carotid T to the thrombus (DT) on coronal maximum intensity projection images and the thrombus length were measured. The correlation between DT and the modified Rankin Scale score at 90 days was analyzed. DT was an independent predictor of clinical outcome in stroke patients treated with IVT. A long DT was significantly correlated with a good clinical outcome (modified Rankin Scale score at 90 days ≤2). A poor clinical outcome was exponentially more likely than a good outcome when the DT was <16 mm (P<0.001). The thrombus length was not correlated with the modified Rankin Scale score at 90 days. A long thrombus (>8 mm) occurred significantly more often in the proximal MCA than the distal MCA (P<0.001). DT is an independent predictor of clinical outcome in patients with acute MCA occlusion treated with IVT. In acute stroke with MCA occlusion confirmed by CT angiography and DT <16 mm, the likelihood of a good clinical outcome after treatment with IVT was exponentially <50%. This might warrant the evaluation of other therapy forms than IVT in patients with proximal MCA occlusion.

Comparison of MR neurography of the brachial plexus with unidirectionally encoded diffusion-weighted imaging with background signal suppression and enhanced three dimensional short inversion time inversion recovery sampling perfection with application optimized contrasts using different flip angle evolutions

Objective To evaluate two different MRI techniques , enhanced 3D STIR SPACE and unidirectionally-encoded DWIBS MR Neurography in visualizing the brachial plexus.Methods Twenty healthy volunteers underwent MR scanning by the procedures of unidirectionally -encoded DWIBS and enhanced 3D STIR SPACE sequence of the brachial plexus.Original images were reconstructed with coronal maximum intensity projection ( MIP ).The image quality was assessed by comparing the visualization of various parts of the brachial plexus and the suppression ratio of image background.The degree of visualization was compared via χ2-test of paired data , and comparison of background suppression scores was performed using a nonparametric Wilcoxon signed rank sum test.Results The successful rate of visualizing the brachial plexus supraclavicular section ( C5-T1 ) was 84% ( 167/200 ) and 99% ( 198/200 ) , respectively, for the DWIBS and enhanced 3D STIR SPACE, and the rate for the infraclavicular section was 33%( 13/40 ) and 95% ( 38/40 ).The differences between these two techniques were statistically significant (χ2 value was 28.18 and 31.15 respectively, P <0.01).In all images, the scores of grade (Ⅰ-Ⅳ) of background suppression were 0, 0, 4 and 16 for unidirectionally-encoded DWIBS, respectively;while they were 15, 4, 1 and 0 for enhanced 3D STIR SPACE.There was significant difference between the two techniques ( Z =3.96,P <0.01).Conclusions High-quality MR neurography of the brachial plexus can be obtained using the enhanced 3D STIR SPACE sequence.It offers a complete anatomical coverage of the brachial plexus , and thus demonstrates a better capacity in depicting the anatomy of brachial plexus as compared with the unidirectionally-encoded DWIBS. Key words: Brachial plexus ; Magnetic resonance imaging ; Comparative study ;

A case of delayed neurological recovery with luxury perfusion and a high intracranial arterial calcification burden.

Dear Sir, Although patients with acute ischemic stroke achieve recanalization, approximately 37%-65% of them do not show immediate improvement.1 The term stunned brain refers to delayed neurological recovery after an ischemic insult to the brain.1 We describe the case of a patient with delayed neurological recovery who had a small cerebral infarction but relatively rapid compensatory perfusion and high calcification burden in the intracranial arteries. A 71-year-old woman visited our emergency room 1.5 hours after developing acute right limb weakness. The initial neurological examination revealed right hemiplegia (arm and leg, grade 2 on the Medical Research Council grading system) and global aphasia (National Institutes of Health Stroke Scale score, 22). Non-enhanced computed tomography did not reveal a definite ischemic or hemorrhagic lesion, and intravenous recombinant tissue plasminogen activator was subsequently infused. Computed tomography angiography revealed a moderate degree of stenosis in the left middle cerebral artery (Figure 1A) and a high calcification burden in almost all intracranial arteries (Figure 1A, B). We assumed that an occlusion of the middle cerebral artery might be in the process of recanalization. Immediate magnetic resonance imaging revealed a small acute infarction near the posterior pole of the lateral ventricle on diffusion-weighted imaging (Figure 1C). Perfusion magnetic resonance imaging performed simultaneously revealed luxury perfusion in the left posterior temporo-parieto-occipital area (Figure 1D). Although her neurological symptoms had improved 24 hours after onset, she still had right hemiparesis (arm and leg, grade 4) and dense sensory aphasia (National Institutes of Health Stroke Scale score, 8). The localization of these neurological deficits corresponded to the area of luxury perfusion. On the fourth day after admission, the small lesion persisted on diffusion-weighted imaging (Figure 1E), and the luxury perfusion had normalized (Figure 1F), but the neurological deficits including sensory aphasia remained (National Institutes of Health Stroke Scale score, 7). By the sixth day after admission, her neurological deficits had completely disappeared. Figure 1 Initial computed tomography (CT) and magnetic resonance (MR) images of the patient in this study. (A) A coronal maximum intensity projection image from CT angiography shows significant stenosis of the distal left middle cerebral artery, which was lined ... The patient showed some immediate neurological recovery, but sensory aphasia persisted even though the diffusion-restricted lesion was small and the cerebral perfusion pattern was compensatory. We propose that this delayed neurological recovery was associated with vascular aging, which was reflected by the high intracranial arterial calcification burden. Calcium deposition in the vasculature is one of the main components of vascular aging,2 which is associated with poor adaptation following ischemia/reperfusion injuries.3 In addition, neovascularization following reperfusion is hampered by the vascular calcification process.4 Reperfusion may result in increased levels of reactive oxygen species that subsequently impair endothelial progenitor cell function.5 With regard to post-stroke repair mechanisms, endothelial progenitor cells are known to be essential for neovascularization.6,7 The delayed neurological recovery could be explained by these poor adaptations and hampered neovascularization following revascularization. The delayed neurological recovery in this patient could also have been associated with the luxury perfusion phenomenon; however, a previous report has shown a relationship with perfusion deficit. Hyperperfusion on perfusion magnetic resonance imaging is thought to reflect a high degree of ischemic stress.8 The hyperperfused area was reported to correspond to the area of cerebral infarction in this patient. When compared to patients with normal perfusion, those with hyperperfusion show lower apparent diffusion coefficient values.8 Moreover, delayed clinical recovery has been reported to be associated with perfusion deficits.1 A defect that extends beyond a diffusion-restricted area is referred to as an ischemic penumbra,9 which exhibits deranged cerebral metabolism and can be identified using perfusion imaging. The present case indicates that either hyperperfusion or hypoperfusion may be associated with delayed neurological recovery after cerebral arterial recanalization.8 In conclusion, the delayed neurological recovery observed in our patient might have resulted from either post-ischemic reperfusion syndrome associated with luxury perfusion, or an impaired post-stroke repair mechanism associated with a high burden of intracranial arterial calcification. Computed tomography and magnetic resonance imaging are both useful for estimating the degree of ischemic injury.

Pulmonary nodule registration in serial CT scans using global rib matching and nodule template matching

We propose an automatic nodule registration method between baseline and follow-up chest CT scans. Initial alignment using the center of the lung volume corrects the gross translational mismatch, and rigid registration using coronal and sagittal maximum intensity projection images effectively refines the rigid motion of the lungs. Nodule correspondences are established by finding the most similar region in terms of density as well as the geometrical constraint. The proposed nodule registration method increased the nodule hit rate (the ratio of the number of successfully matched nodules to total nodule number) from 26% to 100%.