Near-infrared sensitive differential Helmholtz-based hydrogen sulfide photoacoustic sensors.

A near-infrared (NIR) sub-ppm level photoacoustic sensor for hydrogen sulfide (H2S) using a differential Helmholtz resonator (DHR) as the photoacoustic cell (PAC) was presented. The core detection system was composed of a NIR diode laser with a center wavelength of 1578.13 nm, an Erbium-doped optical fiber amplifier (EDFA) with an output power of ∼120 mW, and a DHR. Finite element simulation software was used to analyze the influence of the DHR parameters on the resonant frequency and acoustic pressure distribution of the system. Through simulation and comparison, the volume of the DHR was 1/16 that of the conventional H-type PAC for a similar resonant frequency. The performance of the photoacoustic sensor was evaluated after optimizing the DHR structure and modulation frequency. The experimental results showed that the sensor had an excellent linear response to the gas concentration and the minimum detection limit (MDL) for H2S detection in differential mode can reach 460.8 ppb.

Imaging of the Abdominal Wall Sinus Tract: Comparison of Computed Tomography Sinography and X-Ray Sinography.

OBJECTIVE: The study aims to clarify the comparative benefits of X-ray sinography and computed tomography (CT) sinography in assessing the abdominal wall sinus tract. METHODS: In this cross-sectional study, patients in our hospital with an abdominal wall sinus tract who had received both X-ray sinography and CT sinography from January 2018 to January 2021 were enrolled. The intraoperative findings were used as the gold standard to calculate the accuracy of the two methods. Kappa statistic was employed to evaluate the concordance between the two methods and the intraoperative findings. Differences in diameters measured on X-ray sinography and CT sinography images were analyzed using the Wilcoxon signed rank test. RESULTS: The study sample consisted of 74 patients. The accuracy of the CT sinography in diagnosing the extent of the sinus invasion was 85.1%, while the accuracy of the X-ray sinography was 59.5%. For the sinus confined to the abdominal wall (Kappa: 0.783 VS 0.248), the sinus extending into the abdominal cavity (Kappa: 0.734 VS 0.339), and the sinus with fistula formation (Kappa: 0788 VS 0.496), the consistency of the CT sinography and surgery were significantly better than that of the X-ray sinography. Diameters of the sinus tract measured on CT images were statistically larger than the diameters measured on X-ray sinography (P<0.001). CONCLUSION: CT sinography has significant advantages to X-ray sinography in depicting the extent of the abdominal wall sinus tract and the presence of a fistula.

Value of CT sinography and analysis of missed diagnosis and misdiagnosis for abdominal wall sinus.

BACKGROUND: The value of CT (computed tomography) sinography in evaluating abdominal wall sinus tracts is currently unclear. The present study aims to investigate the accuracy of CT sinography in diagnosing the extent of abdominal sinus and analyze the reasons for misdiagnosis. MATERIALS AND METHODS: 64 patients with abdominal sinus tract formation (including fistula) undergoing CT sinography in our hospital from January 2018 to November 2020 were retrospectively analyzed. The CT images were blindly and independently re-assessed by two radiologists with 5- and 18-years work experience, respectively. Whether the sinus tract was confined to the abdominal wall or had invaded the abdominal cavity, and whether there was fistula formation were evaluated. The accuracy of CT sinography in diagnosing sinus invasion in the abdominal cavity and fistula formation was calculated. The agreements of CT sinography-surgical results and inter-observer were assessed using weighted-kappa statistics. RESULTS: The weighted- Kappa of inter-observer agreement (0.825, P < 0.001) and CT sinography-surgical results (0.828, P < 0.001) were both perfect. The diagnostic accuracy, sensibility, and specificity of sinus tract confined to the abdominal wall were 90.6% (95% CI: 80.7-96.5), 85.7% (95% CI: 67.3-96.0), and 94.4% (95% CI: 81.3-99.3), respectively. The diagnostic accuracy, sensibility, and specificity of fistula formation were 93.8% (95% CI: 84.8-98.3), 89.5% (95% CI: 66.9-98.7), and 95.6% (95% CI: 84.9-99.5), respectively. A total of 4 cases of sinus tract confined to the abdominal wall were misdiagnosed as invading the abdominal cavity, 2 cases of sinus tract invading the abdominal cavity were misdiagnosed as confined to the abdominal wall, 2 cases of enterocutaneous fistula were missed, 1 case of enterocutaneous fistula was misdiagnosed, 1 case of vesico-cutaneous fistula was misdiagnosed, and no cases of vesico-cutaneous fistula were missed. CONCLUSIONS: CT sinography can accurately assess the extent of an abdominal sinus tract and reveal fistula formation, despite some inevitable misdiagnosis and missed diagnosis. Radiologists should find more clues to improve the diagnostic accuracy.

Enhanced computed tomography imaging features predict tumor grade in pseudomyxoma peritonei.

Background: Because few studies have focused on the correlation between computed tomography (CT) signs and tumor grade in pseudomyxoma peritonei (PMP), we evaluated predictive value of abdominal enhanced CT in identifying high- vs. low-grade cases. Methods: In all, 75 patients diagnosed with PMP after surgery were consecutively recruited. The preoperative enhanced CT images were retrospectively analyzed for ascites, hepatic scalloping, omental and peritoneal lesion appearance, intralesional calcification and septa, and peripheral organ involvement. Logistic regression models were applied to analyze the relationship of CT signs with PMP grade. Receiver operating characteristic curves were generated to evaluate the potential utility of CT signs in detecting high-grade PMP. Results: Massive ascites (P=0.017) and peritoneal solid nodules (P<0.001) were more common in high-grade cases. Multivariate logistic regression identified massive ascites [odds ratio (OR) =4.389, 95% confidence interval (CI): 1.210-15.921; P=0.025] and peritoneal solid nodules (OR =19.932, 95% CI: 3.560-111.596; P<0.001) as independent predictors of high-grade PMP. For the 55 patients with hepatic scalloping, the maximum thickness of mucin deposition at the hepatic scalloping wave in high-grade PMP was thinner than that in low-grade PMP (P=0.021). Thickness of mucin deposition at the hepatic scalloping wave (OR =0.346, 95% CI: 0.148-0.809; P=0.014) was an independent predictor of high-grade PMP, with a cutoff value of 18.6 mm. Cancer antigen 125 (CA125) combined with CT signs was significantly better at diagnosing high-grade PMP than was CA125 alone in both the overall patients [area under the ROC curve (AUC): 0.812 vs. 0.656; P=0.020] and those with hepatic scalloping (AUC: 0.859 vs. 0.600; P=0.007). Conclusions: The CT signs of high-grade PMP significantly differ from those of low-grade PMP, and thus combining CT signs with CA125 may be highly valuable for classifying PMP.

Low CT attenuation and high fatty infiltration rate of psoas are risk factors for incisional hernias after appendicectomy: a cross-sectional single-center study from China.

BACKGROUND: Decreased computed tomography (CT) attenuation of muscle is independently associated with muscle weakness. The CT attenuation of the abdominal wall muscles may correlate with that of the psoas in patients without ventral hernias. This means that the CT attenuation of the psoas may be related to the occurrence of incisional hernias (IH). CT-determined sarcopenia was deemed inefficient in predicting the development of IH, while limited attention has been paid to the association between muscle fatty infiltration and incidences of IH. In this study, we aim to investigate whether the psoas' CT measurement parameters, including the average CT attenuation, fatty infiltration rate and psoas muscle index, are associated with IH. METHODS: In this study, adult patients who had undergone an appendicectomy in the past and had then, for any reason, been hospitalised in our hospital from January 2018 to December 2019 were enrolled. The patients were classified into an IH group and a non-IH group. Their psoas' CT attenuation, fatty infiltration rate (FIR) and psoas muscle index (PMI) were measured or calculated. Sarcopenia was defined according to their PMI. Differences between the two groups' indices were then compared. A logistic regression model was applied to assess the effects of psoas' CT measurement parameters on the occurrence of IH. RESULTS: One hundred twenty patients were included in this study. The psoas' CT attenuation (p = 0.031) and PMI (p = 0.042) in the IH group were significantly lower than those in the non-IH group, and FIR in the IH group was significantly higher than in the non-IH group (p < 0.001). The patients' psoas' CT attenuation, FIR, PMI, age, gender and whether they had a history of smoking, were all significant factors in the univariate logistic regression analysis. After adjusting for confounding factors, a multivariate logistic regression analysis demonstrated that the psoas' CT attenuation was an independent protective factor (p = 0.042), and FIR was an independent risk factor (p = 0.018), while neither PMI (p = 0.118) nor sarcopenia (p = 0.663) showed a significant effect on the incidence of IH. CONCLUSIONS: When an appendectomy has been performed, a decreased CT attenuation and increased FIR of the psoas can be considered risk factors for IH.

Computed Tomography-Estimated Pancreatic Steatosis is Associated with Carotid Plaque in Type 2 Diabetes Mellitus Patients: A Cross-Sectional Study from China.

OBJECTIVE: To explore potential effects of pancreatic fat content measured by computed  tomography (CT) on carotid plaque in patients with type 2 diabetes mellitus (T2DM). METHODS: T2DM patients who underwent an un-enhanced CT scan of the upper abdomen and ultrasound of the carotid artery were enrolled. The patients were divided into a non-plaque group and a plaque group (including hypoechoic plaque subgroup and non-hypoechoic plaque subgroup). The CT attenuation of pancreas and spleen were measured. Pancreas-to-spleen attenuation ratio (P/S) and the difference between pancreatic and splenic attenuation (P-S) were calculated. The cutoff values of P/S and P-S were obtained using receiver operating characteristic curves. Logistic regression models were used to evaluate association of P/S or P-S with carotid plaque or hypoechoic plaque. RESULTS: 337 patients were enrolled, including 101 cases in the non-plaque group, 146 cases in the hypoechoic plaque subgroup, and 90 cases in the non-hypoechoic plaque subgroup. P/S and P-S in hypoechoic plaque group were lower than those in non-plaque group, with a cutoff value of P/S and P-S as 0.72 and -13.33, respectively. After adjusting for risk factors, P/S and P-S correlated with carotid plaque [for low P/S: OR (95% CI): 3.15 (1.47-6.73), P = 0.0031; for low P-S: OR (95% CI): 2.84 (1.42-5.66), P = 0.0031] as well as carotid hypoechoic plaque [for low P/S: OR (95% CI): 1.82 (1.07-3.08), P = 0.0259; for low P-S: OR (95% CI): 1.82 (1.09-3.02), P = 0.021]. CONCLUSION: T2DM patients with hypoechoic carotid plaque have higher pancreatic fat content than those without. Pancreatic steatosis correlates with carotid plaque and hypoechoic plaque in T2DM patients.

[Predictive Value of Pancreatic Steatosis for Severity of Coronary Atherosclerosis in Patients with Type 2 Diabetes Mellitus].

Objective To investigate the association of pancreatic steatosis with coronary atherosclerosis in patients with type 2 diabetes mellitus (T2DM). Methods Patients with T2DM who underwent coronary computed tomography angiography(CCTA)in our center due to chest pain were enrolled from January 2016 to February 2019. According to the CCTA findings,patients were divided into normal group,mild-to-moderate coronary atherosclerosis group and severe coronary atherosclerosis group. CT attenuation of pancreas and spleen was measured on abdominal non-enhanced CT,and the CT attenuation indexes including the difference between pancreatic and splenic attenuation (P-S) and the ratio of pancreas-to-spleen attenuation (P/S) were calculated. Analysis of variance or Kruskal-Wallis rank test were used to assess differences among each group. Logistic regression analysis was used to analyze the risk factors of severe coronary stenosis. The accuracy of P/S in predicting severe coronary artery stenosis was assessed by receiver operator characteristic (ROC) curve analysis. Results A total of 173 consecutive T2DM patients were enrolled. These patients included 27 patients with normal coronary artery (15.6%),124 patients with mild to moderate stenosis (71.7%),and 22 patients with severe stenosis (12.7%). There were significant differences in CT attenuation of pancreas (Z=11.543,P=0.003),P-S (Z=11.152,P=0.004) and P/S (Z=11.327,P=0.004) among normal coronary artery group,mild and moderate stenosis group,and severe stenosis group. The CT attenuation of pancreatic head,body,and tail significantly differed in patients with coronary artery stenosis (Z=14.737,P=0.001). After adjusting for confounding factors,multiple Logistic regression showed that P/S (OR=0.062,95%CI=0.008-0.487,P=0.008) was still significantly associated with the severe coronary artery stenosis. The area under the ROC curve of P/S for the diagnosis of severe coronary artery stenosis was 0.701,and the optimal cutoff point was 0.660. Conclusion CT attenuation of pancreas and CT attenuation indexes are associated with the severity of coronary stenosis in T2DM patients,suggesting that pancreatic steatosis may be used as one of the indicators for predicting severe coronary artery stenosis.

Spectrum of IgG4-related disease on multi-detector CT: a 5-year study of a single medical center data.

PURPOSE: To discuss the diverse imaging features of pancreatic and extra-pancreatic lesions of IgG4-related disease (IgG4-RD) on multi-detector CT (MDCT). METHODS: This retrospective study was approved by our institutional research ethics board, and informed consent was waived. From 2008 to 2013, 159 patients including 120 men (mean age 57 years; range 27-79 years) and 39 women (mean age 51 years; range 25-83 years) who met the comprehensive diagnostic criteria for IgG4-RD (2011) were enrolled. MDCT images consisted of 153 abdominal images, 64 pelvic images, 64 thoracic images, and 8 neck images were retrospectively analyzed in consensus by two radiologists with expertise in the CT diagnosis of IgG4-RD. RESULTS: Only 11 (11/153, 7.2%) IgG4-RD patients had been found with no pancreatic involvement. 145 (145/159, 91.2%) patients had various extra-pancreatic lesions, including involvement of biliary tree (93/153, 60.8%), peri-pancreatic vessels (66/153, 43.1%), IgG4-related lymphadenopathy, peri-abdominal aorta arteritis or retroperitoneal fibrosis, head and neck lesions, etc. Renal lesions were found in 26 (26/153, 17.0%) IgG4-RD patients with 4 types of renal parenchymal involvement. Lung lesions were found in 44 (44/64, 68.7%) IgG4-RD patients, which were classified into 7 types. CONCLUSIONS: Pancreatic and various extra-pancreatic lesions may be involved in IgG4-RD patients frequently with typical imaging findings. It is useful to recognize the atypical or uncommon imaging features to help the diagnosis of IgG4-RD together with other serologic or histopathologic findings.