Xeno-learning: knowledge transfer across species in deep learning-based spectral image analysis.

Objective To evaluate and compare the contrast-induced acute kidney injury (CI-AKI) and pathological damage in rats by 3.0 T magnetic resonance imaging (BOLD and ASL-fMRI) . Methods Thirty male SD rats were randomly divided into the control group (at the baseline) and the injection groups (at 20 min, 24 h, 48 h, 72 h and 7 days after the injection of contrast agent) . All rats were scanned by 3.0 TBOLD and ASL-fMRI at the baseline, 20 min, 24 h, 48 h, 72 h and 7 days after the injection of contrast agent. The values of R2* and renal blood flow (RBF) in therenal outer medulla were measured. The renal tubular injury was evaluated after HE staining of the rat kiney. The changes of R2* and RBF values and the pathological changes were evaluated and compared between the two groups. Results The R2* value in the rat kidney increased at 20 min after the injection of contrast agent compared with that at the baseline, and continued to 72 h, and dropped at 7 d, which was equal to that at the baseline. The RBF value increased at 20 min after the injection of contrast agent, and continued to 48 h, and dropped at 72 h, which was lower thanthat at the baseline, until 7 d. The injury of the renal tubules at the renal outer medulla was examined at 20 min after injection of the contrast agent, which was alleviated at 24 h to 48 h, aggravatedat 72 h (better than that at 20 min) , and aggravated again at 7 d (similar to that at 20 min) . The values of R2* and RBF in the renal outer medulla were consistent with the pathologic grading of renal tubular injury, with consistent findings. Conclusion 3.0 T fMRI technique can evaluate the renal blood oxygen pressure and blood perfusion levels induced by CI-AKI, and to a certain extent reflect the pathological damage mechanism of CI-AKI renal injury in rats. Key words: Magnetic resonance imaging; Kidney failure; Contrast media

Quantitative Differences Between the First and Second Injection of Contrast Agent in Contrast-Enhanced Ultrasonography of Feline Kidneys and Spleen

BackgroundMultiple sclerosis (MS) affects the integrity of the blood-brain barrier (BBB). Contrast-enhanced T1 weighted magnetic resonance imaging (MRI) is widely used to characterize location and extent of BBB disruptions in focal MS lesions. We employed quantitative T1 measurements before and after the intravenous injection of a paramagnetic contrast agent to assess BBB permeability in the normal appearing white matter (NAWM) in patients with relapsing-remitting MS (RR-MS).Methodology/Principal FindingsFifty-nine patients (38 females) with RR-MS undergoing immunomodulatory treatment and nine healthy controls (4 females) underwent quantitative T1 measurements at 3 tesla before and after injection of a paramagnetic contrast agent (0.2 mmol/kg Gd-DTPA). Mean T1 values were calculated for NAWM in patients and total cerebral white matter in healthy subjects for the T1 measurements before and after injection of Gd-DTPA. The pre-injection baseline T1 of NAWM (945±55 [SD] ms) was prolonged in RR-MS relative to healthy controls (903±23 ms, p = 0.028). Gd-DTPA injection shortened T1 to a similar extent in both groups. Mean T1 of NAWM was 866±47 ms in the NAWM of RR-MS patients and 824±13 ms in the white matter of healthy controls. The regional variability of T1 values expressed as the coefficient of variation (CV) was comparable between the two groups at baseline, but not after injection of the contrast agent. After intravenous Gd-DTPA injection, T1 values in NAWM were more variable in RR-MS patients (CV = 0.198±0.046) compared to cerebral white matter of healthy controls (CV = 0.166±0.018, p = 0.046).Conclusions/SignificanceWe found no evidence of a global BBB disruption within the NAWM of RR-MS patients undergoing immunomodulatory treatment. However, the increased variation of T1 values in NAWM after intravenous Gd-DTPA injection points to an increased regional inhomogeneity of BBB function in NAWM in relapsing-remitting MS.

To investigate the vasculature of rabbit liver metastatic lesions by color Doppler imaging and power Doppler imaging (PDI) techniques. Eight New Zealand rabbits with implanted VX2 liver tumors were used. All ultrasound examinations were performed with a HP 5500 color Doppler ultrasound scanner. Before and after the injection of contrast agent, the changes of gray scale and the periphery and intralesional blood flow of the liver metastatic lesion were carefully observed by B mode ultrasound, color Doppler flow imaging (CDFI) and PDI. Twelve lesions were found in the eight rabbits with implanted VX2 liver tumors, whose diameter ranged from 1.6 to 4.8 cm. Echoes of these lesions were not characterized and has lack of specificity. After the injection of contrast agent, the numbers of dot or strip-like flow messages increased both at the periphery and inside of these lesions under the mode of CDFI and PDI, and were more pronounced under PDI. Morphology of intralesional vessels extended, even branched and some signals were clearly found encircling the lesion. And some vessels were found penetrating into the center of the lesion. PDI after injection of self-made echo contrast agent can show a pronounced sensitivity than that of B mode ultrasound and CDFI in diagnosis of vascularity of a metastatic lesion.

Acute Mortality in Hospitalized Patients Undergoing Echocardiography With and Without an Ultrasound Contrast Agent (Multicenter Registry Results in 4,300,966 Consecutive Patients)

The purpose of this study was to prospectively evaluate the usefulness of contrast-enhanced power Doppler sonography (PDUS) using a microbubble echo-enhancing agent in differentiating between malignant and benign small breast lesions. Between July 1, 2000, and September 30, 2001, we performed gray-scale sonographic examination of patients in whom diagnostic sonography or screening mammography had revealed solid breast lesions measuring less than 2 cm in the largest dimension. The patients were then examined on PDUS before and after injection of a microbubble contrast agent. The sonographic findings for all 3 techniques, as well as the morphologic features of the Doppler signals for each patient before and after injection of the contrast agent on PDUS, were independently assessed. Each lesion was classified as "benign" or "malignant" on the basis of specific criteria for sonographic interpretation. A hemodynamic study was performed in which time-transit profiles of the Doppler signals on contrast-enhanced PDUS were generated using a computer-assisted program, and the results for each patient were compared with the findings of a histopathologic examination of surgical specimens. Thirty-six patients (35 women and 1 man) with a mean age of 43.5 years (range, 18-69 years) were evaluated. The tumors ranged from 4 to 19 mm in the largest dimension. Histopathologic examination revealed that 19 tumors were benign and 17 were malignant. For morphologic diagnosis of the malignant lesions, the sensitivity of gray-scale sonography was 100%, compared with 29% for PDUS without contrast enhancement. The specificity of gray-scale sonography was 47%, compared with 74% for PDUS without contrast enhancement. Contrast-enhanced PDUS had a sensitivity of 71% and a specificity of 58%. The diagnostic accuracy was 72% for gray-scale sonography, 53% for PDUS without contrast enhancement, and 64% for contrast-enhanced PDUS. The time-transit profiles of the hemodynamic study did not reveal a statistically significant difference in the accuracy rates of contrast-enhanced PDUS between benign and malignant breast lesions. Compared with PDUS without contrast enhancement, contrast-enhanced PDUS provides better visualization of the morphology of vascular Doppler signals that is characteristic of malignancy and therefore has a higher sensitivity and diagnostic accuracy, albeit a lower specificity. In differentiating between benign and malignant small breast lesions, contrast-enhanced PDUS can be helpful when used with gray-scale sonography and PDUS without contrast enhancement.

The goal of this study was to evaluate intraoperative power Doppler ultrasonography when used with a contrast-enhancing agent for operations on intracranial tumors. Forty intracranial tumors were examined using power Doppler ultrasonography with a galactose microparticle-based ultrasonographic contrast-enhancing agent during operations on the brain. The tumors included 37 intracranial neoplasms (14 gliomas, six meningiomas, three hemangioblastomas, two malignant lymphomas, three other primary neoplasms, nine metastatic tumors, and three nonneoplastic lesions). All patients also underwent computerized tomography and magnetic resonance imaging, and all but three of the patients underwent digital subtraction (DS) angiography. Before injection of the ultrasonographic contrast agent, intra- and peritumoral power Doppler flow signals were detected in 32 of the intracranial tumors. After the injection, the signals were enhanced in blood vessels around the tumors and in the tumor parenchyma in 36 tumors. The duration of contrast enhancement continued for 70 to 365 seconds (mean 251.8 +/- 69 seconds) after the injection. Among the tumors, hemangioblastomas displayed particularly strong contrast enhancement. In these intracranial tumors, the echo signals obtained using contrast-enhanced power Doppler ultrasonography correlated with DS angiographic staining. Power Doppler ultrasonograms with the appropriate contrast agent provided better data on the precise real-time position of the tumors and their relationship to adjacent vessels than ultrasonograms obtained before the injection of the contrast agent. Intraoperative power Doppler ultrasonography performed using a contrast-enhancing agent can facilitate intraoperative real-time navigation and assessment of the intratumoral vasculature and peritumoral vessels, particularly for tumors having abundant vessels such as hemangioblastomas.

We assessed the potential usefulness of contrast-enhanced power Doppler ultrasonography (US) for differentiating pancreatic carcinoma from chronic focal pancreatitis. Twenty-six consecutive patients with ductal carcinoma (n=16) and chronic focal pancreatitis (n=10) underwent power Doppler US examinations before and after intravenous injection of an air-based contrast agent (Levovist, Schering, Berlin, Germany). Final diagnosis was obtained by surgery in all patients. The following parameters before and after intravenous administration of contrast agent were evaluated for each lesion: number, morphology and course of the vessels within the lesion and time to maximum detectable enhancement. Number of the lesion vessels and time to maximum enhancement for each lesion were compared by with Student t test. After injection of contrast agent, nine of 16 (56.2%) carcinomas showed a larger total number of vessels (p<0.005) and faster enhancement (p<0.0001) compared with chronic focal pancreatitis. Irregular vessels with a serpiginous course that penetrated the tumor was predominant in carcinoma (eight of 16 cases), whereas focal pancreatitis presented mostly as avascular masses (five of 10 cases). Contrast-enhanced power Doppler US provides useful findings for differentiating pancreatic carcinoma from chronic focal pancreatitis.

Hyperspectral imaging, image analysis and diffusion theory were used to visualize skin vasculature and to monitor the development of fresh skin bruises. Bruises were inflicted in a porcine model, and the development of the hemorrhage was monitored using white light hyperspectral imaging (400-1000 nm). Hyperspectral images from human volunteers were also included in the study. Statistical image analysis was used to classify bruised regions and to visualize the skin vasculature. Biopsies were collected from the animals to reveal the true depth of the bruising. A three-layer diffusion model and an analytic hemoglobin transport model were used to model the reflectance spectra from the images. The results show that hyperspectral images contain depth information, and that the approximate depth and extent of bruises can be retrieved using a combination of statistical image analysis and diffusion theory. This technique also shows potential to visualize vascular structures in human skin.

This review aims to explore recent advancements in optical imaging techniques for monitoring the viability of Deep Inferior Epigastric Perforator (DIEP) flap reconstruction. The objectives include highlighting the principles, applications, and clinical utility of optical imaging modalities such as near-infrared spectroscopy (NIRS), indocyanine green (ICG) fluorescence angiography, laser speckle contrast imaging (LSCI), hyperspectral imaging (HSI), dynamic infrared thermography (DIRT), and short-wave infrared thermography (SWIR) in assessing tissue perfusion and oxygenation. Additionally, this review aims to discuss the potential of these techniques in enhancing surgical outcomes by enabling timely intervention in cases of compromised flap perfusion. A comprehensive literature review was conducted to identify studies focusing on optical imaging techniques for monitoring DIEP flap viability. We searched PubMed, MEDLINE, and relevant databases, including Google Scholar, Web of Science, Scopus, PsycINFO, IEEE Xplore, and ProQuest Dissertations & Theses, among others, using specific keywords related to optical imaging, DIEP flap reconstruction, tissue perfusion, and surgical outcomes. This extensive search ensured we gathered comprehensive data for our analysis. Articles discussing the principles, applications, and clinical use of NIRS, ICG fluorescence angiography, LSCI, HSI, DIRT, and SWIR in DIEP flap monitoring were selected for inclusion. Data regarding the techniques' effectiveness, advantages, limitations, and potential impact on surgical decision-making were extracted and synthesized. Optical imaging modalities, including NIRS, ICG fluorescence angiography, LSCI, HSI, DIRT, and SWIR offer a non- or minimal-invasive, real-time assessment of tissue perfusion and oxygenation in DIEP flap reconstruction. These techniques provide objective and quantitative data, enabling surgeons to monitor flap viability accurately. Studies have demonstrated the effectiveness of optical imaging in detecting compromised perfusion and facilitating timely intervention, thereby reducing the risk of flap complications such as partial or total loss. Furthermore, optical imaging modalities have shown promise in improving surgical outcomes by guiding intraoperative decision-making and optimizing patient care. Recent advancements in optical imaging techniques present valuable tools for monitoring the viability of DIEP flap reconstruction. NIRS, ICG fluorescence angiography, LSCI, HSI, DIRT, and SWIR offer a non- or minimal-invasive, real-time assessment of tissue perfusion and oxygenation, enabling accurate evaluation of flap viability. These modalities have the potential to enhance surgical outcomes by facilitating timely intervention in cases of compromised perfusion, thereby reducing the risk of flap complications. Incorporating optical imaging into clinical practice can provide surgeons with objective and quantitative data, assisting in informed decision-making for optimal patient care in DIEP flap reconstruction surgeries.

Computed tomography-assisted angiography (CTA) for lower limb vasculature can identify perforators only as small as 1mm in diameter. The technique does not clearly show the microvascularity in subdermal layers of the skin. This study investigated a novel method of CTA using intrafemoral injection of contrast medium instead of intravenous injection to display the vascular anatomy of small perforators with a diameter less than 1mm in the lower extremities of rabbits. Posterior thigh perforator surgery was performed for 15 New Zealand rabbits weighing 2.5 to 3.5kg. Five rabbits underwent anatomic dissection to determine the vascular anatomy of the posterior thigh perforator and its location relative to adjacent structures. Of the remaining 10 rabbits, 5 were subjected to CTA scanning after injection of iodine contrast through a microcatheter inserted into the femoral artery, and 5 were subjected to CTA scanning through venous injection of contrast media. The latter group was designated as the control group (10 extremities). Images were viewed using a dedicated workstation. Postoperative outcomes and complications were monitored for 7days after the procedure. All the CTA images of intraartery administration clearly showed that the posterior thigh perforators originated from the popliteal artery. Injection of contrast agent through the femoral artery improved resolution of the CTA, enabling visualization of perforator arteries with diameters in the range of 0.3 to 0.4mm. The images of the control group indicated the course of the perforator in the muscle of only six legs. The images of the remaining four legs did not display the perforator. The CTA-treated animals recovered without any complications. The anatomic dissection matched the CTA mapping. Computed tomography-assisted angiography using intraarterial injection of contrast media enables visualization of vessels smaller than 1mm in diameter. The described animal model also showed the presence of vascular branches in the subdermis. This imaging technique may help in the preoperative design of perforator flaps for use in clinical practice. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

목적: 조영제 주입 후 발생하는 과민반응 중 환자의 열감은 가장 빈번히 발생하는 부작용중 하나로 실제 환자의 체온 측정을 통해 이 열감이 체온의 상승으로 나타나는지 확인해보고자 한다. 대상 및 방법: 2017년 8월 1일부터 2017년 12월 31일까지 Neck CT (contrast)검사를 시행한 100명의 환자를 대상으로 검사전 액와와 이마(오른쪽 눈썹)의 체온을 기준으로 하여 조영제 주입 후 2분(min)까지 10초 간격으로 측정하였다. 조영제 주입속도 (m/sec)와 양(ml)은 본원의 프로토콜 규정에 따라 2.7m/sec와 90ml로 고정하였다. 측정된 결과는 검사 전 측정값을 T0, 조영제 주입 후부터 30초까지를 T1, 40~70초까지 T2, 80~100초까지를 T3로 구분하여 통계적 분석을 통해 온도변화를 확인하였다. 검사 종료 후 열감의 유무와 정도를 알아보기 위에 리커트 척도(5점)로 기록하였다. 결과: 조영제 주입 시 100명중 88명(88%)이 열감을 느꼈고, 열감의 정도는 리커트 척도 5점기준 3.04점이 나왔다. 이 열감을 실제 측정해본 결과 T0 36.51℃을 기준으로 하였을 때 조영제 주입 후 30초까지 T1에서는 36.53℃로 체온의 변화가 없었고, 40~70초까지 T2에서는 36.72℃로 약 0.22℃ 체온이 상승하였다. 80~100초 구간(T3)은 36.75℃로 T2구간의 체온과 거의 비슷하게 유지되었다. 이 결과는 액와와 이마부위 두 군데 모두 거의 일치하였다. 결론: 조영제 주입으로 인한 열감은 100% 신체의 체온변화로 나타난다는 결과는 유추할 수 없었으나, 대부분의 환자에서 온도 변화를 발견할 수 있었다.Purpose: The heat sensation of the patient during hypersensitivity reactions after contrast media injection is one of the most frequent side effects. The actual patient s body temperature is measured to ascertain whether this heat sensation is caused by a rise in body temperature. Material and methods: A total of 100 patients who underwent Neck CT (contrast) test from August 1, 2017 to December 31, 2017 were measured for pre-test body temperature of axillary and forehead (right eyebrow) at intervals of 10 seconds after the injection of contrast agent. The contrast agent injection rate (m/sec) and volume (ml) were fixed at 2.7 m/sec and 90 ml according to the hospital’s protocol of this application. The measured results were divided into T0, before measurement, T1 for 30 seconds after the injection of contrast agent, T2 for 40 to 70 seconds, and T3 for 80 to 100 seconds and the temperature change was confirmed through statistical analysis. To determine the presence and degree of heat sensitivity after the test, it was recorded by a Likert scale (5 points). Result: 88 patients (88%) felt the feeling of heat, and the degree of sensation of heat was 3.04 points on the 5 points of the Likert scale. The result of the actual measurement of the heat sensation shows that there was no change in body temperature at T1 with 36.53°C for 30 seconds after injection of contrast agent, and at T2 with 36.72°C, an increase of 0.25°C during 40 to 70 seconds. The interval between 80 and 100 seconds (T3) was 36.75℃, which was almost similar to the T2 interval temperature. The results were almost identical in both axillary and forehead areas. Conclusion: It could not be referred from the results that the body temperature must change by heat sensation after injectiong contrast media. However, it was found that body temperature was changed in most patients.

Tripartite-GAN: Synthesizing liver contrast-enhanced MRI to improve tumor detection.

Purpose: The purpose of this study was to evaluate the usefulness of three experimental blood pool contrast agents for equilibrium phase magnetic resonance angiography. Materials and Methods: MR angiography was performed in 21 rabbits before and 1, 5, 10, 20 and 30 minutes and 24 hours after the injection of gadolinium-based blood pool contrast agents (Gadomer-17, Gadofluorine M,) and superparamagnetic iron oxide blood pool agent (Ferucarbotran). 3D TOF SPGR images of the thoracic and abdominal aorta (and involving the renal arteries) were obtained. The signal difference-to noise ratios (SDNRs) were measured over time in the aorta. These images were then compared to that of images with Gd-DTPA. Results: MR angiography with the three blood pool agents yielded excellent visualization results of the rabbit abdominal aorta. At the same dose, the three agents provided a significant increase of the aorta-to-tissue SDNR in comparison with that achieved with the Gd-DTPA (a 250% increase for Gadomer-17, a 124% increase for Gadofluorine and a 88% increase for Ferucarbotran). The SDNRs using Ferucarbotran especially showed continuously increasing values to 30 minutes after the injection of contrast agent. Conclusion: The three blood pool agents were found to be very useful contrast agents for equilibrium phase MR angiography.

This study aimed to evaluate the application value of personalized patient protocol technology (P3T) modular cardiac injection technique combined with the iterative reconstruction algorithm, sinogram-affirmed iterative reconstruction (SAFIRE) in coronary computed tomography angiography (CCTA). A retrospective analysis was performed on 40 patients who underwent CCTA at the Central Hospital Affiliated to Shandong First Medical University. Patients were divided into two groups: control group (n=20), which received the traditional contrast agent injection with fixed iodine load and injection flow rate, and filtered back projection reconstruction with filtered back projection (FBP), and experimental group (n=20), which employed a dosing protocol calculated based on P3T cardiac modular parameters, with SAFIRE strength 3 reconstruction. The two groups were compared regarding CT values (proximal, middle, and distal segments), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), coronary imaging quality score, contrast agent flow rate, injection volume, and effective radiation dose (ED). There were no significant differences in CT values of the right coronary artery, anterior descending artery, or circumflex artery at the proximal and middle segments between the two groups (P>0.05). However, the experimental group exhibited significantly higher CT values at the distal segments of these coronary arteries compared to the control group (P<0.05). SNR, CNR, and coronary imaging quality scores showed no significant differences between the two groups (P>0.05). The contrast agent flow rate and injection volume in the experimental group were significantly lower than those in the control group (P<0.05). Additionally, the volume CT dose index (CTDIvol), dose length product (DLP), and ED were significantly reduced in the experimental group compared to the control group (P<0.05). The combination of P3T technology with SAFIRE reconstruction in CCTA effectively reduces contrast agent flow rate, injection volume, and radiation dose without compromising image quality. This approach enables individualized, standardized, and consistent injection schemes.