Lymphangiography and lymphatic embolisation for the treatment of chyle leaks after neck surgery: assessment of lymphangiography findings and embolisation techniques.

OBJECTIVE: To assess lymphangiography findings and outcome of lymphatic embolisation to manage chyle leak after neck surgery. METHODS: Consecutive cases of lymphangiography performed between April 2018 and May 2022 for management of chyle leaks related to neck surgery were retrospectively reviewed. Lymphangiography findings, techniques, and outcomes were analysed. RESULTS: Eight patients (mean age: 46.5 years) were included. Six patients had undergone radical neck dissection for thyroid cancer, and two had undergone lymph node excision. Clinical presentations were: chyle drainage through Jackson Pratt catheters in five patients, lymphorrhea through surgical wounds in two, and enlarging lymphocele in one. Lymphangiography techniques included: inguinal lymphangiography in four patients, retrograde lymphangiography in three, and transcervical lymphangiography in one. Lymphangiography revealed leaks in the terminal thoracic duct in two patients, bronchomediastinal trunk in two, jugular trunk in three, and superficial neck channels in one. Embolisation techniques included: non-selective embolisation of terminal thoracic duct (n = 2), selective embolisation of the jugular trunk (n = 3), selective embolisation of the bronchomediastinal trunk (n = 2), and intranodal glue embolisation of superficial neck channels (n = 1). One patient underwent a repeat procedure. Chyle leak resolved in all patients over a mean of 4.6 days. No complication was encountered. CONCLUSION: Lymphatic embolisation seems to be effective and safe in managing chyle leaks after neck surgery. Lymphangiography allowed for the categorisation of chyle leaks according to their location. Post-embolisation patency of the thoracic duct may be preserved in chyle leaks that do not directly involve the thoracic duct. ADVANCES IN KNOWLEDGE: Lymphatic embolisation is safe and effective in managing chyle leaks after neck surgery. On lymphangiography, the location of contrast media extravasation may not be consistent. The technique for embolisation should be based on the location of the leak. Post-embolisation patency of the thoracic duct may be preserved in chyle leaks that do not directly involve the thoracic duct.

Lateral topography for reducing effective dose in low-dose chest CT.

OBJECTIVE: The purposes of this study were to assess radiation exposure during low-dose chest CT by using lateral topography and to compare the lateral topographic findings with findings obtained with anteroposterior topography alone and anteroposterior and lateral topography combined. SUBJECTS AND METHODS: From November 2011 to February 2012, 210 male subjects were enrolled in the study. Age, weight, and height of the men were recorded. All subjects were placed into one of three subgroups based on the type of topographic image obtained: anteroposterior topography, lateral topography, and both anteroposterior and lateral topography. Imaging was performed with a 128-MDCT scanner. CT, except for topography, was the same for all subjects. A radiologist analyzed each image, recorded scan length, checked for any insufficiencies in the FOV, and calculated the effective radiation dose. One-way analysis of variance and multiple comparisons were used to compare the effective radiation exposure and scan length between groups. RESULTS: The mean scan length in the anteroposterior topography group was significantly greater than that of the lateral topography group and the combined anteroposterior and lateral topography group (p < 0.001). The mean effective radiation dose for the lateral topography group (0.735 ± 0.033 mSv) was significantly lower than that for the anteroposterior topography group (0.763 ± 0.038 mSv) and the combined anteroposterior and lateral topography group (0.773 ± 0.038) (p < 0.001). CONCLUSION: Lateral topographic low-dose CT was associated with a lower effective radiation dose and scan length than either anteroposterior topographic low-dose chest CT or low-dose chest CT with both anteroposterior and lateral topograms.

iNOS promotes HBx-induced hepatocellular carcinoma via upregulation of JNK activation.

Inducible nitric oxide (iNOS) is closely correlated with chronic inflammation in hepatitis B virus X protein (HBx)-induced hepatocellular carcinoma (HCC). However, the molecular mechanisms through which iNOS contribute to hepatocarcinogenesis remain poorly understood. Therefore, we investigated the role of iNOS in signaling pathways underlying HBx-induced liver tumorigenesis. iNOS deletion showed a marked decrease in the hepatic tumor size and stage of HBx transgenic (Tg) mice, indicating a strong contribution of iNOS signaling pathways to hepatocarcinogenesis. In addition, we found that nitric oxide (NO) increased HBx mRNA by recruiting CREB to the CRE site of HBV enhancer in HepG2 cells, suggesting a positive feedback loop between HBx and iNOS signaling pathway. Moreover, iNOS-modulated JNK activation was associated with sustained upregulation of Cyclin D1 in HBxTg mice and HepG2-HBx cells. These results imply that iNOS may play a key role in HBx-associated HCC development. Taken together, our findings demonstrate that iNOS aligns with HBx to promote tumor progression. These findings provide a better understating of the mechanism involving HBx-mediated hepatic tumorigenesis and selective inhibition of iNOS may have therapeutic applications in HBx-associated HCC.

Asymptomatic brain lesions in pilots: a comparative study with non-flying personnel using brain MRI.

INTRODUCTION: As modern aircraft fly at higher altitudes with rapid velocity, pilots have been put in the environment with a possible increasing risk of brain injury and could sustain cumulative brain damage. However, very few studies have investigated brain lesions using MRI in asymptomatic pilots. We evaluated asymptomatic pilots for the presence of cerebral lesions using MRI. METHODS: Enrolled were 31 healthy pilots of the Republic of Korea Air Force (ROKAF) on active flight duty and 31 healthy nonflying ROKAF personnel with ages of or over 45. We checked for the presence of acute and/or chronic medical conditions, smoking habits, alcohol intake, blood pressure, blood tests including lipid panel, glucose, and liver panel, aircraft type, flight hours, flight altitude, and white matter hyperintensities (WMH) on brain MRI. RESULT: The mean age of both groups was 51.2 yr and the mean total flight hours of the pilots was 3025.0 h. There was no statistical difference between the pilots and non-flying personnel for WMH findings (54.8%/ vs. 32.3%). Of the factors related to flight, only the flying altitude (OR 1.005) was significantly related to the presence of WMH on multivariate analysis. Glucose levels and cholesterol levels were also related to WMH. DISCUSSION: Despite our negative results, there could be the possibility of cumulative brain damage in asymptomatic pilots considering the positive effect of altitude and the positive trend of pilots for the presence of WMH. Additional investigations are surely needed.

Low-dose chest computed tomography as a screening tool: findings in 536 aircrews.

BACKGROUND: Plain chest radiographs and pulmonary function tests have been used for pulmonary screening for flight duties of aircrews of the Republic of Korea Air Force. However, the screening accuracy of plain chest radiographs is controversial. Chest CT imaging with low-dose protocol (LDCT) improves detection of intra-thoracic abnormalities compared to plain chest radiographs. The aim of this study was to assess the influence of LDCT on flight duties of aircrews and to investigate their radiologic findings. METHODS: From June 2009 to May 2011, the Aerospace Medical Center screened asymptomatic subjects 40 yr of age or older to evaluate intra-thoracic abnormalities using LDCT. The abnormal findings, including types and frequency, were recorded and the aircrew's flight duties were also recorded. RESULTS: This study included 536 subjects. No abnormal findings were found in 387 (72.2%) subjects. Abnormal findings related to pulmonary nodules were detected in 123 (23.00%) subjects. Air-trapping lesions were found in 33 (6.1%) subjects. One subject had a mediastinal tumor. Changes of flight duty were made in 26 (4.9%) subjects on the basis of LDCT findings. No subject was permanently disqualified for flight duty. CONCLUSIONS: Pulmonary screening with LDCT could detect many intra-thoracic abnormalities. LDCT was especially useful in the detection of bullae and bleb, and the flight duties of all subjects with bullae and bleb were changed.

Gd-EOB-DTPA enhanced micro-MR imaging of hepatic tumors in H-ras 12V transgenic mice.

RATIONALE AND OBJECTIVES: The aims of this study were to evaluate the morphologic characteristics and growth pattern of hepatic tumors in H-ras 12V transgenic (TG) mice using a micro-magnetic resonance (MR) system and to assess the usefulness of gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA) enhancement for the detection of hepatic tumors in these mice. MATERIALS AND METHODS: Hepatocellular carcinoma lines were established to allow insertion of the H-ras 12V transgene under the control of the albumin enhancer/promoter. Seven H-ras 12V TG mice and four wild-type mice were included in this study. The mice underwent various MR imaging examinations, including T1-weighted imaging (repetition time, 300 ms; echo time, 11 ms), Gd-EOB-DTPA-enhanced T1-weighted imaging (dose, 0.025 mmol/kg), and T2-weighted imaging (repetition time, 3500 ms; echo time, 36 ms), with a 4.7-T MR scanner, at 4, 6, 8, and 9 months of age. All mice were euthanized after the final MR imaging procedure, except for one TG mouse and two wild-type mice that were euthanized after MR imaging procedures at 4 months of age. For imaging analysis, the tumor characteristics in each MR sequence, including tumor size, number, and signal intensity (SI), were recorded, and the contrast-to-noise ratio and contrast enhancement ratio were calculated to quantify the SI of the tumor. The MR images were correlated with the findings of histopathologic examinations. RESULTS: No tumors were detected in the four wild-type mice. In the six TG mice, a total of 67 tumors were found in histopathologic specimens obtained at 9 months of age. Of the 67 tumors, 62 were detected on Gd-EOB-DTPA-enhanced T1-weighted images with fat saturation. The majority of hepatic tumors showed high SI on T1-weighted images without fat saturation. The SI diminished on T1-weighted images with fat saturation. The tumor contrast-to-noise ratio for Gd-EOB-DTPA-enhanced T1-weighted imaging was significantly better than that for the other sequences. The tumors were histopathologically confirmed as hepatocellular adenomas (n = 32) and well-differentiated hepatocellular carcinomas (n = 35). CONCLUSIONS: Micro-MR imaging can reveal the characteristics of hepatic tumors in a live murine model. Gd-EOB-DTPA-enhanced T1-weighted imaging is helpful in the detection of hepatic tumors in H-ras 12V TG mice.