Objective To investigate the value of flexible subtraction CE-Boost technique combined with low dosage contrast agents for CT pulmonary angiography(CTPA).Methods A total of 68 patients who would undergo CTPA examination due to suspected pulmonary embolism(PE)were prospectively enrolled and randomly divided into study group(n=34)and control group(n=34)using block randomization method.After injecting 25 ml contrast agents at a flow rate of 2.5 ml/s in study group or 50 ml contrast agents at a flow rate of 3.5 ml/s in control group,CTPA scanning were performed with identical parameters.For images in study group,hybrid iterative reconstruction was performed,followed by flexible subtraction CE-Boost post-processing to obtain CE-Boost CTPA.For images in control group,conventional CTPA was obtained with hybrid iterative reconstruction.Subjective and objective evaluations of image quality were compared between groups.Taken the final clinical diagnosis as standard,the accuracy rate of diagnosing PE were compared between groups.Results There were 7 cases of pulmonary artery main trunk PE and 15 cases of pulmonary lobe-level PE in study group,while in control group there were 8 cases and 17 cases.No statistical difference of subjective scores of CTPA was found between groups(P＞0.05).CT values of the main pulmonary artery,bilateral pulmonary artery trunks and lower lobes of both lungs,signal-to-noise ratio or contrast-to-noise ratio in CTPA were not significantly different between groups(all P＞0.05),while no significant difference of the accuracy rate of CTPA for diagnosing PE of pulmonary artery main trunk(100％[7/7]vs.100％[8/8])nor pulmonary lobe-level PE(86.67％[13/15]vs.88.24％[15/17])was detected between groups(all P＞0.05).Conclusion Flexible subtraction CE-Boost technique combined with low dosage contrast agents for CTPA could reduce contrast agent dosage without affecting image quality.

Objective To observe the value of high-resolution direct MRI using hydrogen peroxide for diagnosing complex or recurrent anal fistulas.Methods Data of preoperative specialized physical examination,transperineal ultrasound(TPUS),pelvic cavity low-resolution plain MRI and fistula high-resolution direct MRI of 27 patients with complex or recurrent anal fistulas confirmed by surgery were retrospectively analyzed.The receiver operating characteristic(ROC)curves were constructed,and the area under the curves(AUC)were calculated to assess the diagnostic performance of the above 4 methods for identifying internal openings,tracts of fistulas and perianal abscesses.Results Among 27 cases,totally 51 internal openings,54 fistula tracts(including 30 intersphincteric,18 transsphincteric,3 extrasphincteric and 3 suprasphincteric fistulas)and 18 perianal abscesses were found.The efficacy of high-resolution direct MRI for diagnosing internal opening of complex or recurrent anal fistula(AUC=0.880)was higher than that of specialized physical examination,TPUS and low-resolution plain MRI(AUC=0.553,0.687,0.687,all P＜0.05),and the efficacy of high-resolution direct MRI for diagnosing tract of complex or recurrent anal fistula(AUC=0.889)was higher than that of specialized physical examination and TPUS(AUC=0.556,0.694,both P＜0.05),but not significantly different with low-resolution plain MRI(AUC=0.833,P＞0.05).The efficacy of high-resolution direct MRI for diagnosing perianal abscesses of complex or recurrent anal fistula(AUC=0.971)was higher than that of specialized physical examination(AUC=0.549,P＜0.05)and comparable to TPUS and low-resolution plain MRI(AUC=0.745,0.858,both P＞0.05).Conclusion High-resolution direct MRI using hydrogen peroxide was helpful for diagnosing complex or recurrent anal fistulas.

Right heart dysfunction is a key impact factor of prognosis of various cardiovascular diseases,yet the assessment of right heart function has long been overlooked in management of cardiovascular diseases.Cardiac MR feature tracking(CMR-FT)is an emerging technique that enables quantitative analysis of global and regional strain without the need for additional imaging sequences.The advancements of CMR-FT for assessing right heart strain were reviewed in this article.

Reconstruction of low-dose CT image faced problems such as low resolution,blurred artifacts and strong noise.Deep learning reconstruction met the needs of reducing radiation dose and improving imaging quality,promoted reconstruction of CT image towards high efficiency,intelligence and integration of clinical diagnosis and treatment.The research progresses in deep learning low-dose CT imaging reconstruction were reviewed in this article.

Precise preoperative assessment of cervical cancer facilitates personalized treatment and reduces the burden of retreatment.In recent years,various quantitative techniques of relaxation time,including T1 mapping,T2 mapping,T2*mapping,blood oxygenation level dependent MRI,synthetic MRI and MR fingerprinting,had demonstrated certain progresses,providing novel approaches for non-invasive evaluation of cervical cancer.The research progresses in quantitative MR relaxation time techniques of cervical cancer were reviewed in this article.

The heart-brain axis is the core of human homeostasis regulation,and its functional abnormalities are the key link connecting cardiovascular and nervous system disorders.Ischemic heart disease(IHD)not only impairs the structure and function of myocardium,but also causes cognitive dysfunction through the disorder of heart-brain interaction pathways.Its essence lies in the multi-dimensional damage to the structure and function of brain caused by the pathological state of the heart.Multimodal neuroimaging techniques have important value for studying mechanisms of heart-brain interaction.MRI and PET can accurately assess pathological changes such as brain structural and functional damage,metabolic abnormalities and neuroinflammation.The neuroimaging for early identification,formulating heart-brain co-treatment strategies and improving the management level of IHD related cognitive dysfunction were reviewed in this article.

To face the huge challenges in visualization and diagnosis of intricate structures and lesions in head and neck,hence to make these structures and lesions visible,distinct,accurate and comprehensive for precise diagnosis and treatment,a multidisciplinary medicine-engineering collaboration platform was established.With this platform,a multitude of multimodal cross-scale quantitative imaging equipment and technologies were developed innovatively and optimized continually,thereby overcoming long-standing bottlenecks in visualization,diagnosis and evaluation of head and neck structures and diseases.Moreover,these advanced equipment and technologies were translated into clinical practice,and a patient-centered,clinical problem-oriented system of imaging examination,diagnosis,evaluation and prediction in head and neck was established,which could provide objective evidences for diagnosis and treatment,revise the therapeutic strategies,and significantly improve diagnosis and management of head and neck diseases.

Non-ischemic cardiomyopathy(NICM)encompasses heterogeneous subtypes and complex etiology,and sudden cardiac death(SCD)is a particularly severe adverse outcome of NICM.Cardiac magnetic resonance(CMR)has capability of multiparametric micro-tissue characterization,multi-sequence macroscopic morpho-structural imaging and multi-dimensional quantitative analysis of cardiac function,which plays a central role in diagnosis and sub-typing,evaluating risk stratification and assessment of treatment response of NICM.The clinical application status and cutting-edge progresses of CMR in NICM were systematically described in this article.

Over the past four decades,respiratory imaging has achieved a leapfrogging development from conventional morphological assessment to precision medicine.Beginning with conventional X-ray that laid the foundation,followed by CT technological breakthroughs,MRI explorations,and advances in nuclear medicine and molecular imaging,this review outlined the key technologies and clinical translation achievements at each stage,analyzed current research hotspots such as artificial intelligence and radiomics,radiation protection in low-dose CT,and integration of functional and molecular imaging,prospected the future trends in early diagnosis,treatment monitoring,and synergy with targeted therapy,emphasizing the paradigm shift in this field from empirical diagnosis to data-driven precise evaluation,as well as its core supportive role in diagnosis and management of respiratory diseases.

Respiratory dynamic imaging can continuously capture the morphology,position and functional changes of lung tissue during respiratory cycles in real time,hence providing quantitative information for diagnosing lung diseases,assessing disease severity,formulating treatment strategies and evaluating treatment outcomes.The development and application progresses of respiratory dynamic imaging technology were reviewed in this article.