Retrolaminar migration as a complication of intraocular silicone oil injection detected on unenhanced CT.

AIM: To describe the clinical and radiologic features of retrolaminar migration silicone oil (SiO) and observe the dynamic position of ventricular oil accumulation in supine and prone. METHODS: For this retrospective study, 29 patients who had a history of SiO injection treatment and underwent unenhanced head computed tomography (CT) were included from January 2019 to October 2022. The patients were divided into migration-positive and negative groups. Clinical history and CT features were compared using Whitney U and Fisher's exact tests. The dynamic position of SiO was observed within the ventricular system in supine and prone. CT images were visually assessed for SiO migration along the retrolaminar involving pathways for vision (optic nerve, chiasm, and tract) and ventricular system. RESULTS: Intraocular SiO migration was found in 5 of the 29 patients (17.24%), with SiO at the optic nerve head (n=1), optic nerve (n=4), optic chiasm (n=1), optic tract (n=1), and within lateral ventricles (n=1). The time interval between SiO injection and CT examination of migration-positive cases was significantly higher than that of migration-negative patients (22.8±16.5mo vs 13.1±2.6mo, P<0.001). The hyperdense lesion located in the frontal horns of the right lateral ventricle migrated to the fourth ventricle when changing the position from supine to prone. CONCLUSION: Although SiO retrolaminar migration is unusual, the clinician and radiologist should be aware of migration routes. The supine combined with prone examination is the first-choice method to confirm the presence of SiO in the ventricular system.

Engineering a Ratiometric Photoacoustic Probe with a Hepatocyte-Specific Targeting Ability for Liver Injury Imaging.

In situ imaging of biological indicators is imperative for pathological research by utilizing an activatable photoacoustic (PA) probe. However, precise imaging in actual applications is hampered by the inevitable poor accumulation and low sensitivity. Herein, an amphiphilic molecular probe (AP) was rationally constructed as proof of concept for in situ imaging of drug-induced liver injury, which consists of a hydrophilic target unit and a superoxide anion radical (O2•-)-sensitive small-molecule PA moiety. The probe AP successfully realizes the selectivity and sensitivity toward O2•- in vitro and in living cells. Notably, the amphiphilic probe AP can be selectively retained in the liver and activated toward endogenous O2•- through receptor-mediated endocytosis inside hepatocytes. By virtue of the highly efficient accumulation at the liver, AP was further applied to assess isoniazid-induced liver injury through desired ratiometric PA signals. In addition, based on the fluctuation of O2•-, the therapeutic efficacy of hepatoprotective medicines for hepatotoxicity was analyzed in vivo. Therefore, the O2•--specific probe could serve as a promising molecular tool for early diagnosis study of other liver diseases and analysis of new potential therapeutic agents.

Predicting Chronic Myocardial Ischemia Using CCTA-Based Radiomics Machine Learning Nomogram.

BACKGROUND: Coronary computed tomography angiography (CCTA) is a well-established non-invasive diagnostic test for the assessment of coronary artery diseases (CAD). CCTA not only provides information on luminal stenosis but also permits non-invasive assessment and quantitative measurement of stenosis based on radiomics. PURPOSE: This study is aimed to develop and validate a CT-based radiomics machine learning for predicting chronic myocardial ischemia (MIS). METHODS: CCTA and SPECT-myocardial perfusion imaging (MPI) of 154 patients with CAD were retrospectively analyzed and 94 patients were diagnosed with MIS. The patients were randomly divided into two sets: training (n = 107) and test (n = 47). Features were extracted for each CCTA cross-sectional image to identify myocardial segments. Multivariate logistic regression was used to establish a radiomics signature after feature dimension reduction. Finally, the radiomics nomogram was built based on a predictive model of MIS which in turn was constructed by machine learning combined with the clinically related factors. We then validated the model using data from 49 CAD patients and included 18 MIS patients from another medical center. The receiver operating characteristic curve evaluated the diagnostic accuracy of the nomogram based on the training set and was validated by the test and validation set. Decision curve analysis (DCA) was used to validate the clinical practicability of the nomogram. RESULTS: The accuracy of the nomogram for the prediction of MIS in the training, test and validation sets was 0.839, 0.832, and 0.816, respectively. The diagnosis accuracy of the nomogram, signature, and vascular stenosis were 0.824, 0.736 and 0.708, respectively. A significant difference in the number of patients with MIS between the high and low-risk groups was identified based on the nomogram (P < .05). The DCA curve demonstrated that the nomogram was clinically feasible. CONCLUSION: The radiomics nomogram constructed based on the image of CCTA act as a non-invasive tool for predicting MIS that helps to identify high-risk patients with coronary artery disease.

Prediction of the progression from mild cognitive impairment to Alzheimer's disease using a radiomics-integrated model.

OBJECTIVE: This study aimed to build and validate a radiomics-integrated model with whole-brain magnetic resonance imaging (MRI) to predict the progression of mild cognitive impairment (MCI) to Alzheimer's disease (AD). METHODS: 357 patients with MCI were selected from the ADNI database, which is an open-source database for AD with multicentre cooperation, of which 154 progressed to AD during the 48-month follow-up period. Subjects were divided into a training and test group. For each patient, the baseline T1WI MR images were automatically segmented into white matter, gray matter and cerebrospinal fluid (CSF), and radiomics features were extracted from each tissue. Based on the data from the training group, a radiomics signature was built using logistic regression after dimensionality reduction. The radiomics signatures, in combination with the apolipoprotein E4 (APOE4) and baseline neuropsychological scales, were used to build an integrated model using machine learning. The receiver operating characteristics (ROC) curve and data of the test group were used to evaluate the diagnostic accuracy and reliability of the model, respectively. In addition, the clinical prognostic efficacy of the model was evaluated based on the time of progression from MCI to AD. RESULTS: Stepwise logistic regression analysis showed that the APOE4, clinical dementia rating, AD assessment scale, and radiomics signature were independent predictors of MCI progression to AD. The integrated model was constructed based on independent predictors using machine learning. The ROC curve showed that the accuracy of the model in the training and the test sets was 0.814 and 0.807, with a specificity of 0.671 and 0.738, and a sensitivity of 0.822 and 0.745, respectively. In addition, the model had the most significant diagnostic efficacy in predicting MCI progression to AD within 12 months, with an AUC of 0.814, sensitivity of 0.726, and specificity of 0.798. CONCLUSION: The integrated model based on whole-brain radiomics can accurately identify and predict the high-risk population of MCI patients who may progress to AD. Radiomics biomarkers are practical in the precursory stage of such disease.

Precipitated Fluorophore-Based Probe for Accurate Detection of Mitochondrial Analytes.

Mitochondria-targeted fluorescent probes are highly important to obtain mitochondrial function information. However, the accuracy of the current mitochondria-targeted fluorescent probes is unsatisfactory owing to the following two reasons. In the first case, some probes that always have a mitochondria-targeting group, thus, would react with the analytes outside of mitochondria and enter mitochondria with the generated fluorophore signal, which leads to a false-positive result. In the other case, after response to the analytes in mitochondria, some probes could diffuse from mitochondria to other organelles, thus triggering a false-negative result. To avoid the two problems, herein, we develop a precipitated fluorophore-based probe, which precipitates in situ after reacting with analytes, for the accurate detection of mitochondrial analytes. The probe was modified with HQPQ, a novel solid-state fluorophore that is insoluble in water. As a proof of concept, we designed and synthesized a probe (HQPQ-B) for H2O2 detection. Based on the different mitochondria-targeting capacities of quinoline salts and quinolone, HQPQ loses the mitochondria-targeting ability after reacting with analytes outside of mitochondria, thus avoiding a false-positive result. On the contrary, when the probe first localized in mitochondria and then reacted with analytes, HQPQ would precipitate and remain in mitochondria without diffusing to other sites, thus avoiding a false-negative result. Therefore, HQPQ enables the accurate detection of mitochondrial analytes. We believe that the novel strategy based on HQPQ will be a general strategy for accurate detection of mitochondrial analytes without interference from other sites, which enables an accurate study on mitochondrial function.

Radiomics nomogram based on MRI for predicting white matter hyperintensity progression in elderly adults.

BACKGROUND: White matter hyperintensity (WMH) is widely observed in aging brain and is associated with various diseases. A pragmatic and handy method in the clinic to assess and follow up white matter disease is strongly in need. PURPOSE: To develop and validate a radiomics nomogram for the prediction of WMH progression. STUDY TYPE: Retrospective. POPULATION: Brain images of 193 WMH patients from the Picture Archiving and Communication Systems (PACS) database in the A Medical Center (Zhejiang Provincial People's Hospital). MRI data of 127 WMH patients from the PACS database in the B Medical Center (Zhejiang Lishui People's Hospital) were included for external validation. All of the patients were at least 60 years old. FIELD STRENGTH/SEQUENCE: T1 -fluid attenuated inversion recovery images were acquired using a 3T scanner. ASSESSMENT: WMH was evaluated utilizing the Fazekas scale based on MRI. WMH progression was assessed with a follow-up MRI using a visual rating scale. Three neuroradiologists, who were blinded to the clinical data, assessed the images independently. Moreover, interobserver and intraobserver reproducibility were performed for the regions of interest for segmentation and feature extraction. STATISTICAL TESTS: A receiver operating characteristic (ROC) curve, the area under the curve (AUC) of the ROC was calculated, along with sensitivity and specificity. Also, a Hosmer-Lemeshow test was performed. RESULTS: The AUC of radiomics signature in the primary, internal validation cohort, external validation cohort were 0.886, 0.816, and 0.787, respectively; the specificity were 71.79%, 72.22%, and 81%, respectively; the sensitivity were 92.68%, 87.94% and 78.3%, respectively. The radiomics nomogram in the primary cohort (AUC = 0.899) and the internal validation cohort (AUC = 0.84). The Hosmer-Lemeshow test showed no significant difference between the primary cohort and the internal validation cohort (P > 0.05). The AUC of the radiomics nomogram, radiomics signature, and hyperlipidemia in all patients from the primary and internal validation cohort was 0.878, 0.848, and 0.626, respectively. DATA CONCLUSION: This multicenter study demonstrated the use of a radiomics nomogram in predicting the progression of WMH with elderly adults (an age of at least 60 years) based on conventional MRI. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:535-546.

Consistency of radiologists in identifying pulmonary nodules based on low-dose computed tomography.

BACKGROUND: To study the consistency of radiologists in identifying pulmonary nodules based on low-dose computed tomography (LDCT), and to analyze factors that affect the consistency. METHODS: A total of 750 LDCT cases were collected randomly from three medical centers. Three experienced chest radiologists independently evaluated and detected the pulmonary nodules on 625 cases of LDCT images. The detected nodules were classified into 3 groups: group I (detected by all radiologists); group II (detected by two radiologists); group III (detected by only one radiologist). The consistency with respect to the image features of individual nodules was assessed. RESULTS: A total of 1,206 nodules were identified by the three radiologists. There were 234 (19.4%) nodules in group I, 377 (31.3%) nodules in group II, and 595 (49.3%) nodules in group III. Logistic regression showed that the size, density, and location of the nodules correlated with the detection of nodules. Nodules sized great than or equal to 4 mm were more consistently identified than nodules sized less than 4 mm. Solid and calcified nodules were more consistently identified than sub-solid nodules. Nodules located in the outer zone were more consistently identified than hilar nodules. CONCLUSIONS: There was considerable inter-reader variability with respect to identification of pulmonary nodules in LDCT. Larger nodules, solid or calcified nodules, and nodules located in the outer zone were more consistently identified.

[Clinical characteristics of 42 cases of spontaneous intracranial hypotension with cerebrospinal leakage].

OBJECTIVE: To review the clinical characteristics of spontaneous intracranial hypotension (SIH) with cerebrospinal fluid (CSF) leakage. METHODS: Clinical data of 42 SIH patients with cerebrospinal leakage, whose diagnosis met the criteria of the International Headache Classification, were retrospectively reviewed. The patients were divided into short (n=27) and long (n=15) course groups. The clinical data and imaging features were compared between two groups. RESULTS: Thirty-nine patients (92.9%) had orthostatic headache. Compared with the short course group, the frequency of headache were significantly lower in patients with long disease duration (80% vs 100%, P =0.040); the ratio of high CSF opening pressure (>=60.0 mm H2O), the average CSF opening pressure, and the frequencies of subdural hematoma were higher in long course group than those in short course group [60.0% vs 20.8%, (64.7±42.1) vs (40.0±33.8)mm H2O, and 50.0% vs 11.6%; P=0.019, 0.038 and 0.018, respectively]. Forty-two patients underwent CT myelography;definite focal CSF leakage sites were found in all patients and multiple sites of CSF leakage in 38 patients. CONCLUSION: All SIH do not necessarily show the typical clinical manifestations, and cranial MRI and CT myelography are helpful in the diagnosis. Because of higher risk of subdural hemorrhage, patients with long disease duration require active intervention.

Somatotopic reorganization of hand representation in bilateral arm amputees with or without special foot movement skill.

Bilateral arm amputees usually are excellent foot users. To explore the plasticity of the primary motor cortex in upper-extremities amputees and to determine if the acquisition of special foot movement skill is related with the bilateral hand amputation, we studied the primary motor cortex by using combined task and resting state functional magnetic resonance imaging (fMRI). We investigated 6 bilateral arm amputees with or without special foot movement skill. In the task fMRI study, we found that toe tapping of all the amputees activated the bilateral hand area, including cases without special foot skill. In addition, cases without special foot skill mainly activated the precentral gyrus, which differed from those with more adept foot motor skill who activated both the precentral and postcentral gyri. To further understand the plasticity of the hand area, the resting state functional connectivity was investigated between the foot and hand regions. One-tailed two-sample t-test suggested that the connections between two areas became significantly stronger in the amputee group. Our study demonstrates that hand region of the cortex does not remain 'silent' after bilateral arm amputation, but rather is recruited by other modalities such as adjacent or nonadjacent cortexes to process motor information in a functionally relevant manner. From the data presented, it seems that the bilateral arm amputees have a strong potential to develop new skills in their remaining extremities and practice may further enhance this potential.

Syncope induced by acute pulmonary embolism in aged patients: a report of four cases.

Syncope is a common presentation in the neurology clinic and emergency room. However, pulmonary embolism (PE) as a cause of syncope is not common or well recognized. Four aged patients presented to our clinic with episodic syncope, and PE was finally identified as the underlying cause. The significant clinical presentations included transient loss of consciousness and hypoxemia on admission. Syncope with hypoxia should therefore be highlighted as an important clue to the diagnosis of PE in aged patients. A negative D-dimer test will be encountered in patients with a very short history. Repeated D-dimer testing is necessary.

Differentiation of white and red thrombus with magnetic resonance imaging: a phantom study.

BACKGROUND: An early identification of the composition of arterial thrombus may have diagnostic, therapeutic, and prognostic implications. The variation of magnetic resonance (MR) signal intensity between white and red thrombi, especially in the susceptibility sensitive MR sequence, remains unknown. Our research was to evaluate the feasibility of MRI in differentiating of white and red thrombi with a phantom study. METHODS: A total of 12 red and 12 white thrombi were prepared with the venous blood. Examination of the phantom was completed using a 3.0T MR unit, including fluid attenuated inversion recovery (FLAIR) T1, T2-weighted imaging (T2WI), FLAIR T2, T2 gradient echo (T2 GRE) imaging, and susceptibility weighted angiography sequences (SWAN). MR signal intensity patterns of the thrombi were objectively classified as hyperintensity, isointensity and hypointensity, compared with the background agar. The volume of thrombus was calculated and correlated with its signal intensity. RESULTS: For white thrombi, 11/12 clots showed hyperintensity and 1/12 showed isointensity in FLAIR T1 images. In T2WI, 6/12 clots showed hyperintensity, 3/12 isointensity, and 3/12 hypointensity. In FLAIR T2, 8/12 clots showed hyperintensity and 4/12 showed isointensity. In T2 GRE, 3/12 clots showed hyperintensity and the remaining 9/12 clots showed isointensity. In SWAN, 5/12 clots demonstrated hyperintensity and 7/12 isointensity. For the red thrombus, 12/12 clots demonstrated hyperintensity in FLAIR T1, T2WI, and FLAIR T2 sequences. In T2 GRE and SWAN sequences, 3/12 clots displayed hypointensity and the remaining 9/12 clots showed slight hyperintensity. Thrombi with hypointensity displayed in T2 GRE and SWAN sequences were significantly larger than those with hyperintensity. CONCLUSIONS: Differentiation of white and red thrombi with conventional MR sequence is unreliable, because both kinds of thrombi do not possess unique signal intensity features in these sequences. Red thrombus may or may not show hypointensity in the susceptibility sensitive MR sequences, depending on its size and time course.

Transient small bowel angioedema due to intravenous iodinated contrast media.

Three cases of transient proximal small bowel angioedema induced by intravenous administration of nonionic iodinated contrast media (CM) are presented. Computed tomography (CT) images in the venous phase displayed the proximal small bowel with circumferential thickening of the wall including the duodenum and proximal segment of the jejunum. The bowel wall was normal in non-enhanced images, and normal or inconspicuous in arterial phase enhanced images. In one of the three cases, the bowel wall was thickened in venous phase but disappeared in the 40 s delayed phase images. No filling defect was seen in the lumen of the superior mesenteric artery and vein. No peritoneal effusion or mesentery abnormality was found. Each of these patients reported only mild abdominal discomfort and recovered without specific treatment within a short time. Only one patient suffered mild diarrhea after scanning which had resolved by the following day. The transient anaphylactic small bowel angioedema due to intravenous iodinated contrast media was easily diagnosed based on its characteristic CT findings and clinical symptoms. Differential diagnosis may include inflammatory and ischemic bowel disease, as well as neoplasms. A three-phase CT protocol and good understanding of this disorder are fundamentally important in the diagnosis of this condition. The supposed etiology behind the transient anaphylactic reaction to intravenous administration of iodinated CM in small bowel is similar to other CM-induced hypersensitive immediate reactions. The predilection location of transient anaphylactic bowel angioedema is the small intestine, particularly the proximal segment. A speculated cause may be the richer supply of vessels in the small intestine, ample mucous folds and loose connective tissue in the duodenum and the jejunum.

Prevalence of nerve-vessel contact at cisternal segments of the oculomotor nerve in asymptomatic patients evaluated with magnetic resonance images.

BACKGROUND: Some studies indicated that cases of idiopathic oculomotor nerve palsy can be explained by vascular compression of the oculomotor nerve. Vascular contact with or compression to the cisternal segment of the oculomotor nerve has been reported frequently in asymptomatic individuals. In this study, we retrospectively analyzed the relationship between the oculomotor nerve's cisternal segment and adjacent arteries in asymptomatic patients and the prevalence of this occurrence via magnetic resonance imaging (MRI). METHOD: MRI of bilateral oculomotor nerves in 93 asymptomatic patients were reviewed. The oculomotor nerve-artery relationship was evaluated and classified from levels 1 to 3, representing the degrees of contact on oblique transverse and oblique sagittal reconstructed MRI. Prevalence of the nerve-artery relationship at each level was described. The correlation between the nerve-vessel relationship (levels) and the age was analyzed by Spearman's rank correlation analysis. RESULTS: Cisternal segment of the oculomotor nerve did not have contact with any artery (level 1) in 27.4% (51/186) nerves. One hundred nerves made contact with at least one artery (level 2), but their shapes or configurations were not changed; 35 nerves (18.8%) were displaced or distorted due to artery compression (level 3). The posterior cerebral artery had the greatest incidence of making contact with or compressing the cisternal segment of the oculomotor nerve (58.1%). No significant correlation between nerve-vessel relationship (levels) and the age was found in this study. CONCLUSIONS: Whether oculomotor nerve contact with or compression by one or more arteries is of high prevalence in asymptomatic individuals as evidenced by MRI examination. There is no correlation with individual age. Discretion should be used when making an etiological diagnosis of vascular compression for patients with oculomotor nerve palsy. Further investigation of other causes is warranted.

[Artifacts from dental metal alloys in magnetic resonance imaging].

OBJECTIVE: To evaluate the artifact sizes at 3.0 T compared to at 1.5 T caused by three kinds of metallic dental materials, and to evaluate the influences of different magnetic resonance imaging (MRI) sequences on the artifact. METHODS: Samples of metal-ceramic crown of three kinds of dental materials (Ni-Cr alloy, Co-Cr alloy, and gold alloy) were placed in a cylindrical plastic vessel filled with agarose gel. Acrylic resin crown was used as control. Images were performed by means of 1.5 T and 3.0 T MRI apparatus with 4 different sequences commonly used in brain MRI sequences. Artifact diameter was calculated and compared quantitatively. A 4 x 4 x 2 factorial design was applied to determine the effects on the MRI artifact of different metal materials, different sequences, and different magnetic field strengths. RESULTS: ANOVA of factorial design showed that the influences of material, magnetic field strength, and sequence were all significantly different( materials: F = 124.796, df = 3, P = 0.000; magnetic field strength: F = 9.367, df = 1, P = 0.003; sequence: F = 3.020, df = 3, P = 0.036). Among the 3 kinds of alloys, the gold alloy produced the least artifact. Among the 4 imaging sequences, fast spin echo (FSE) produced the least artifact. The artifact sizes increased at 3.0 T compared to at 1.5T. Interactions among the 3 factors did not influence the artifacts significantly (P > 0.05). CONCLUSION: Selection of specific metal material and imaging sequence can minimize the metal artifacts in MRI. The increment of artifacts at 3.0 T is only by 10% compared to that at 1.5 T. But 3.0 T MRI system has great advantages, so it is eligible on patients with metal restoration.

[An experimental study of the effects of root-canal treatment on orthodontic movement in cat cuspids].

PURPOSE: To evaluate the effectiveness of orthodontic forces in moving teeth after root canal therapy and the risk of apical resorption which may happen during orthodontic movement in an animal model. METHODS: Under general anesthesia, root canal therapy was performed on the mandibular canines on one side of 16 adult cats. Tipping movement of the canines was induced with an orthodontic spring (100 to 120 g). Eight weeks later, tooth movement was assessed from pre- and posttreatment mandibular casts, including measurement of root lengths in both radiographs and histological sections. All the data were analysed with SPSS 11.0 for windows. Student's t test was used for comparisons between paired groups. RESULTS: The results showed that teeth after root canal therapy and vital teeth moved similar distances when subjected to the same forces (P>0.05). And teeth after root canal therapy had greater loss of cementum after tooth movement than vital teeth (P<0.05), but without significant differences in radiographic root length (P>0.05). CONCLUSIONS: Teeth after root canal therapy can be moved orthodontically as readily as vital teeth when subjected to the same orthodontic forces under the conditions of the study. However, teeth after root canal therapy have more root resorption than vital teeth during orthodontic movement which may not be detected form the radiography.