Purpose To investigate the impact of patient positioning deviation on CT image quality and radiation dose in chest CT scans.Materials and Methods A retrospective analysis was conducted on all patients who underwent chest high-resolution CT plain scans from January 22 to 26,2024,at the Second Affiliated Hospital,Zhejiang University School of Medicine.The distance between the gantry center and patient center was measured.Patients were divided into three groups based on the magnitude of deviation from the isocenter:negative deviation group,isocenter group and positive deviation group.Compared the signal to noise ratio(SNR),CT dose index volume(CTDIvol),dose length product(DLP)and SNR/CTDI distribution among the three patient groups.Results Among the 965 patients studied,29.95%(289 cases)were accurately positioned,while 70.05%(676 cases)deviated from the center.The frequency of positive deviation(31.81%,307/965)was lower than that of negative deviation(38.24%,369/965).Compared with the isocenter group,patients in the negative deviation group received higher CTDIvol and DLP but superior SNR,while those in the positive deviation group received lower CTDIvol and DLP with inferior SNR(H=213.783,187.595,59.247,all P<0.05).The SNR/CTDI ratio in the isocenter group 0.84(0.50)was significantly higher than that in the negative deviation group 0.72(0.54)and the positive deviation group 0.71(0.38)(H=13.257,P<0.05).There was a significant association between gender and deviation direction.Patients with higher body weight and taller stature,particularly male patients,demonstrated negative deviation,while those with lower body weight and shorter stature tended to positive deviation.Conclusion Accurate positioning in chest CT scans can ensure diagnostic accuracy while minimizing radiation exposure and achieving the best image quality-to-radiation dose ratio.However,as a population-based preliminary study,the findings should be complemented by phantom experiments to further validate the correlation between anthropometric parameters and positional deviations in clinical CT practice.

Purpose To explore the diagnostic efficacy of 99Tcm labeled fibroblast activation protein inhibitor(FAPI)SPECT/CT for metastatic lesions in advanced colorectal cancer and its impact on decisions regarding immunotherapy,and to compare it with 18F-FDG PET/CT.Materials and Methods A total of 34 patients with advanced colorectal cancer who underwent both 99Tcm-FAPI SPECT/CT and 18F-FDG PET/CT imaging from August 2022 to November 2023 in Fuzhou University Affiliated Provincial Hospital were prospectively included.The gold standard was based on biopsy or clinical and imaging follow-up results.Chi-square tests and rank sum tests were used to compare differences between the groups.Results Among the 34 patients,17 patients subsequently received immunotherapy.The uptake of 99Tcm-FAPI was significantly higher than that of 18F-FDG for the primary tumor site(Z=-2.389,P=0.017),peritoneal metastasis(Z=-2.497,P=0.013)and liver metastasis(Z=-0.106,P=0.015).The diagnostic efficacy of 99Tcm-FAPI SPECT/CT for patients with peritoneal metastasis was superior to that of 18F-FDG PET/CT(χ2=4.65,P=0.033).Metastatic lesions that did not uptake 99Tcm-FAPI had a better clinical prognosis after immunotherapy(χ2=11.839,P=0.006),and maximum standardized uptake value(SUVmax)-FDG/SUVmax-FAPI ratio was a promising predictive factor for a better prognosis after immunotherapy,with an optimal cut-off value of 5.04.Conclusion 99Tcm-FAPI SPECT/CT has superior diagnostic efficacy for peritoneal metastasis in advanced colorectal cancer compared with 18F-FDG PET/CT.SUVmax-FDG/SUVmax-FAPI ratio is a promising radiomic parameter for predicting patient prognosis after immunotherapy,which can help guide clinical decision-making further.

In recent years,with the continuous advancement of MRI technology,5.0T MRI has gradually become a focal point of interest in both clinical and research fields.Compared with traditional 1.5T and 3.0T systems,the signal-to-noise ratio on the 5.0T platform increases superlinearly,while certain tissue properties such as T1 values,T2(T2*)values change,making chemical shift phenomena and susceptibility effects more pronounced.This brings new application prospects for fat suppression,magnetic resonance spectroscopy and functional imaging techniques.Despite the challenges that the 5.0T system faces in terms of main magnetic field(B0)uniformity,radiofrequency field(B1)distribution and specific absorption rate control,these issues have been effectively mitigated through hardware innovation,sequence optimization and intelligent control technologies.The system shows significant advantages in conventional and functional imaging in areas such as the nervous system,bone joints,cardiovascular and cerebrovascular,and abdominal regions.This article discusses the technological breakthroughs,clinical application potential and future challenges of 5.0T MRI technology based on the latest research progress.

Purpose To evaluate the differential diagnostic value of 5.0T MRI susceptibility-weighted imaging(SWI)in hepatocellular carcinoma(HCC)and mass-forming intrahepatic cholangiocarcinoma(MICC).Materials and Methods A total of 56 patients with HCC and 36 patients with MICC confirmed by pathology from March 2023 to November 2024 in Anhui Provincial Hospital were retrospectively enrolled.Two radiologists independently analyzed three features of the lesions,including the low-signal rims around the lesion,hemorrhage within the lesion,and the relationship between lesions and adjacent vessels,on the SWI sequence between the two groups,respectively,via inter-rater consistency analysis.These above features between the two groups were compared and contrasted them with those obtained from conventional MR plain and enhanced scans,respectively.For intralesional hemorrhages,the diagnostic value was quantified by calculating the internal tissue susceptibility signal.Results The radiologists showed good consistency in the low-signal rims,intratumoral hemorrhage as well as the relationship between the lesion and the blood vessel on the SWI in the HCC group and the MICC group(Kappa=0.802-0.929,all P<0.001).Compared with conventional MR plain,SWI significantly enhanced the detection rates of perilesional low-signal rims and intratumoral hemorrhage(χ2=89.409,46.210,both P<0.001).These findings were more prevalent in HCC patients.The internal tissue susceptibility signal grading showed that HCC predominantly exhibited grade 3,whereas MICC predominantly exhibited grade 1,with statistically significant differences(Z=-4.059,P<0.05).Additionally,compared with enhanced MRI,SWI demonstrated higher accuracy in diagnosing the relationship between lesions and blood vessels in both groups;however,these differences were not statistically significant(χ2=0.275,0.247,P=0.871,0.619).In the HCC group,the relationship between tumors and blood vessels was primarily characterized by compression and tumor thrombus formation,while in the MICC group,it was predominantly marked by invasive changes,including vessel encasement,stenosis or occlusion,with a statistically significant difference between the two groups(Z=-6.809,P<0.001).Conclusion SWI sequence of 5.0T MRI provides clear visualization of the internal and peripheral structures of HCC and MICC.It can accurately delineate the relationship between lesions and blood vessels without the need for contrast agents,offering significant clinical utility in differentiating these two conditions.

Purpose To provide technical support for the use of echo-planar imaging(EPI)in the diagnosis of brain diseases,the image quality and diagnostic effect of single-shot echo-planar imaging(ssEPI)diffusion-weighted imaging(DWI)and multi-shot echo-planar imaging(msEPI)DWI sequences in the detection of brain diseases at 5.0T MR are analyzed.Materials and Methods A retrospective analysis was conducted on 42 patients with intracranial diseases who underwent T2-FLAIR,ssEPI DWI and msEPI DWI scans on a 5.0T MR system in the First Affiliated Hospital of USTC from August to September 2023.Two radiologists independently assessed image quality,measured distortion displacement,and compared signal-to-noise ratio,lesion-to-normal tissue contrast,contrast-to-noise ratio and apparent diffusion coefficient.Results msEPI sequence demonstrated significantly superior subjective scores,including geometric distortion,susceptibility artifacts,edge sharpness and overall image quality compared with those of ssEPI sequence(Z=5.728,4.197,5.766,5.777,all P<0.001).Quantitative analysis revealed substantial reduction in distortion displacement in msEPI sequence,including frontal lobe[(5.91±1.41)mm vs.(15.63±2.21)mm,t=34.050,P<0.001],anterior temporal lobe[(4.17±0.78)mm vs.(7.18±1.87)mm,t=12.263,P<0.001],posterior temporal lobe[(4.76±1.36)mm vs.(8.38±2.01)mm,t=21.336,P<0.001],cerebral diameter[(4.37±1.65)mm vs.(12.74±2.84)mm,t=23.255,P<0.001]and brainstem diameter[(0.80±0.63)mm vs.(1.98±1.63)mm,t=7.092,P<0.001],compared with ssEPI sequence.However,no statistically significant differences were observed in signal-to-noise ratio or contrast-to-noise ratio between the two sequences(P=0.848,0.638).Notably,msEPI sequences exhibited significantly enhanced lesion-normal tissue contrast compared with ssEPI sequences[221(131,311)vs.150(90,240),Z=3.89,P<0.001].Conclusion At 5.0T MRI,msEPI demonstrated superior image quality and diagnostic performance for craniocerebral diseases compared to ssEPI DWI sequences.

Purpose To summarize the MRI characteristics of patients with spontaneous spinal subdural hematoma,so as to strengthen the awareness to this disease,and to improve the clinical diagnosis and treatment ability.Materials and Methods A retrospective analysis was performed on five patients with spontaneous spinal subdural hematoma diagnosed and treated in Qingdao Chengyang District People's Hospital from January 2021 to December 2023.Plain MRI and enhanced MRI were performed 6-24 hours after onset,and the imaging characteristics were analyzed.Combined with the dynamic American Spinal Injury Association(ASIA)grading score and disease progression,three patients were treated with surgery and two patients with conservative treatment.Results All patients were followed up for 6-15 months.Among the five patients,the hematoma was distributed at the cervicothoracic junction in two cases,the upper thoracic segment in one case and the thoracolumbar segment in two cases;covering 3-6 segments in two cases,2-3 segments in two cases and 1 segment in one case;hematoma was located at the ventral side of the dural sac in two cases,and the dorsal side of the dural sac in three cases.Postoperative pathology showed that one case was simple blood clot,and two cases were blood clot with a large number of neutrophil infiltration.One case was hyperacute phase with isointensity on T1WI and high signal on T2WI,three cases were acute phase with isointensity on T1WI and low signal on T2WI,and one case was subacute phase with high signal on T1WI and low signal on T2WI.Enhanced scanning showed that one case was uneven enhancement,one case was irregular edge enhancement and three cases had no obvious enhancement.ASIA grade of two cases returned to E,one case returned to C after surgery,and lower limb muscle strength of two cases returned to E after conservative treatment,and MRI reexamination showed that the hematoma was absorbed.Conclusion MRI has strong sensitivity for the lesions of patients with spontaneous spinal subdural hematoma,which can accurately show the location and size of the hematoma,help to distinguish the progression of the disease,and has great significance for clinical diagnosis and treatment.

Purpose To explore the feasibility and clinical value of deep learning-based image reconstruction technology in 5.0T MRI for nasopharyngeal carcinoma.Materials and Methods A prospective study was conducted on 50 newly diagnosed nasopharyngeal carcinoma patients from August to December 2024 at Sun Yat-sen University Cancer Center.5.0T MRI was performed to scan the nasopharynx region.Routine scanning protocols included transverse T2WI,transverse T1WI,transverse contrast-enhanced T1WI and coronal fat-suppressed contrast-enhanced T1WI sequences.Based on these standard scanning protocols,DeepRecon deep learning reconstruction technology with different levels(grade 1-5)was applied,generating a total of 24 sets of images.Qualitative evaluation employed a Likert scale(5-point system)for subjective scoring on lesion detection,lesion edge clarity,artifacts and overall image quality.Quantitative evaluation was performed using the signal-to-noise ratio and contrast-to-noise ratio to objectively assess the quality of the 24 image sets.Differences in qualitative and quantitative indicators between different groups were compared,while the Kappa coefficient was used to analyze the consistency of subjective evaluations by two radiologists.Results In the qualitative assessment of 24 image sets from four MRI sequences(with and without DeepRecon reconstruction),DeepRecon images(grade 2-4)significantly outperformed traditional images in all features except for artifact reduction(Z=-12.11--6.23,all P<0.001).Images reconstructed at DeepRecon grade 3 had the highest overall score and the best image quality.Furthermore,compared with traditional images,DeepRecon images(grade 2-5)demonstrated significantly improved signal-to-noise ratio for both lesions and the lateral pterygoid muscle(t=-15.67--3.44,Z=-6.09--4.63,all P<0.01).In addition,in the transverse T2WI,transverse contrast-enhanced T1WI and coronal fat-suppressed contrast-enhanced T1WI images with DeepRecon reconstruction(grade 2-5),the contrast-to-noise ratio(lesion/lateral pterygoid muscle)also showed significant improvement compared to traditional images(t=-12.71--3.19,Z=-6.08--4.47,all P<0.001).The inter-observer agreement for the overall subjective quality score between the two radiologists was good(Kappa=0.75-0.82,all P<0.01).Conclusion DeepRecon deep learning reconstruction technology significantly increases the signal-to-noise ratio and resolution of traditional magnetic resonance images of nasopharyngeal cancer,improving image clarity and bringing more possibilities for the advancement of imaging diagnosis.

Purpose To explore the application value of cardiac magnetic resonance(CMR)mapping and strain techniques in assessing ventricular function changes in patients with severe alcohol use disorder(AUD).Materials and Methods A retrospective analysis was conducted on 32 male patients with severe AUD as the study group in Hefei Fourth People's Hospital from January 2023 to April 2024,compared with 30 age-and gender-matched healthy subjects as the control group.Clinical data and CMR results were collected for all participants.CMR parameters included conventional functional parameters such as left and right ventricular ejection fraction,volume index and mass index;tissue characterization parameters such as Native T1,T2 mapping and extracellular volume fraction(ECV);and strain parameters including global longitudinal strain(GLS),global circumferential strain(GCS)and global radial strain(GRS)for both ventricles.The differences in the above indexes between the two groups were compared.Results The left ventricular end-diastolic volume index in the AUD group was significantly higher than in the control group(t=3.799,P<0.001).The left ventricular strain values(GLS,GCS,GRS)in the AUD group were significantly lower than those in the control group(t=4.459,4.435,-4.759,all P<0.001).The Native T1,T2 and ECV in the AUD group were significantly higher than those in the control group(t=6.301,5.650,7.069,all P<0.001).For the right ventricle,only right ventricular GLS and right ventricular GCS were significantly lower than in the control group(t=8.703,-2.814,both P<0.01).Conclusion CMR feature tracking technology can early identify ventricular function abnormalities in AUD patients.The increase in Native T1,T2 mapping and ECV suggests the presence of myocardial edema and fibrosis in AUD patients,which is closely related to left ventricular dysfunction.Multi-parameter CMR evaluation provides important diagnostic evidence for the early detection of cardiac involvement in severe AUD patients.

Radiotherapy is fundamental in managing malignant brain tumors,where precise implementation depends on accurate assessment of tumor boundary and therapeutic response.The role of amino acid tracers,notably 18F-FET PET imaging with its superior tumor contrast,offers significant value in radiotherapy management by enhancing diagnostic accuracy for recurrence and guiding personalized therapy.This article mainly summarizes recent applications of 18F-FET PET in adjuvant radiotherapy planning,treatment response monitoring and prognostic evaluation.

Tumor heterogeneity is a central cause of treatment resistance and poor prognosis.Habitat imaging,an emerging paradigm in medical image analysis,decomposes tumors into distinct subregions-known as"habitats"-with varying pathophysiological features through unsupervised clustering and other computational methods.This approach enables spatial visualization and quantitative characterization of the tumor microenvironment,offering a feasible tool for non-invasive assessment of tumor heterogeneity.This commentary outlines the technical principles of habitat imaging,elaborates on its methodology for generating habitat maps based on multimodal imaging and clustering algorithms,and highlights its performance-particularly when integrated with radiomics-in predicting treatment response,survival outcomes and genetic profiles.Although it shows promising potential across various cancer types,including glioblastoma and breast cancer,the clinical translation of habitat imaging still faces multiple challenges.Future progress will require standardization,improved biological validation and rigorous clinical trials to advance precision oncology.