Posttreatment Head and Neck Cancer Imaging: Anatomic Considerations Based on Cancer Subsites.

Posttreatment imaging surveillance of head and neck cancer is challenging owing to complex anatomic subsites and diverse treatment modalities. Early detection of residual disease or recurrence through surveillance imaging is crucial for devising optimal treatment strategies. Posttreatment imaging surveillance is performed using CT, fluorine 18-fluorodeoxyglucose PET/CT, and MRI. Radiologists should be familiar with postoperative imaging findings that can vary depending on surgical procedures and reconstruction methods that are used, which is dictated by the primary subsite and extent of the tumor. Morphologic changes in normal structures or denervation of muscles within the musculocutaneous flap may mimic recurrent tumors. Recurrence is more likely to occur at the resection margin, margin of the reconstructed flap, and deep sites that are difficult to access surgically. Radiation therapy also has a varying dose distribution depending on the primary site, resulting in various posttreatment changes. Normal tissues are affected by radiation, with edema and inflammation occurring in the early stages and fibrosis in the late stages. Distinguishing scar tissue from residual tumor becomes necessary, as radiation therapy may leave behind residual scar tissue. Local recurrence should be carefully evaluated within areas where these postradiation changes occur. Head and Neck Imaging Reporting and Data System (NI-RADS) is a standardized reporting and risk classification system with guidance for subsequent management. Familiarity with NI-RADS has implications for establishing surveillance protocols, interpreting posttreatment images, and management decisions. Knowledge of posttreatment imaging characteristics of each subsite of head and neck cancers and the areas prone to recurrence empowers radiologists to detect recurrences at early stages. ©RSNA, 2024 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

2021 WHO Classification of Lung Cancer: Molecular Biology Research and Radiologic-Pathologic Correlation.

The 2021 World Health Organization (WHO) classification system for thoracic tumors (including lung cancer) contains several updates to the 2015 edition. Revisions for lung cancer include a new grading system for invasive nonmucinous adenocarcinoma that better reflects prognosis, reorganization of squamous cell carcinomas and neuroendocrine neoplasms, and description of some new entities. Moreover, remarkable advancements in our knowledge of genetic mutations and targeted therapies have led to a much greater emphasis on genetic testing than that in 2015. In 2015, guidelines recommended evaluation of only two driver mutations, ie, epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) fusions, in patients with nonsquamous non-small cell lung cancer. The 2021 guidelines recommend testing for numerous additional gene mutations for which targeted therapies are now available including ROS1, RET, NTRK1-3, KRAS, BRAF, and MET. The correlation of imaging features and genetic mutations is being studied. Testing for the immune biomarker programmed death ligand 1 is now recommended before starting first-line therapy in patients with metastatic non-small cell lung cancer. Because 70% of lung cancers are unresectable at patient presentation, diagnosis of lung cancer is usually based on small diagnostic samples (ie, biopsy specimens) rather than surgical resection specimens. The 2021 version emphasizes differences in the histopathologic interpretation of small diagnostic samples and resection specimens. Radiologists play a key role not only in evaluation of tumor and metastatic disease but also in identification of optimal biopsy targets. ©RSNA, 2024 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Imaging of salivary gland cancers derived from a sublingual gland herniated into the submandibular space: a report of three cases.

Sublingual gland herniation into the submandibular space through a mylohyoid muscle defect is a common anatomical variation; however, salivary gland cancers that arise from a herniated sublingual gland have not been described yet. Here, we report three patients with salivary gland cancers originating from a herniated sublingual gland. All tumors were detected as palpable submandibular masses, located anterior to the submandibular gland, medial to the mandible, and lateral to the mylohyoid muscle, with contact with the sublingual gland through a mylohyoid muscle defect. Intraoperative findings confirmed that the masses were derived from herniated sublingual glands. Pathological examination showed one case of mucoepidermoid carcinoma and two cases of adenoid cystic carcinoma. Imaging findings of the tumor location, in addition to the continuity with the sublingual gland through the mylohyoid muscle defect, are crucial for accurately diagnosing the tumor origin, which is essential for determining the appropriate clinical management.

Imaging Approach for Cervical Lymph Node Metastases from Unknown Primary Tumor.

Neck swelling due to lymph node (LN) metastasis is one of the initial symptoms of head and neck cancer, and in some cases, the primary tumor is not clinically evident. The purpose of imaging for LN metastasis from an unknown primary site is to identify the primary tumor or detect its absence, which leads to the correct diagnosis and optimal treatment. The authors discuss diagnostic imaging approaches for identifying the primary tumor in cases of unknown primary cervical LN metastases. The distribution and characteristics of LN metastases may help locate the primary site. Unknown primary LN metastasis often occurs at nodal levels II and III, and in recent reports, these were mostly related to human papillomavirus (HPV)-positive squamous cell carcinoma of the oropharynx. Another characteristic imaging finding suggestive of metastasis from HPV-associated oropharyngeal cancer is a cystic change in LN metastases. Other characteristic imaging findings such as calcification may help predict the histologic type and locate the primary site. In cases of LN metastases at nodal levels IV and VB, a primary lesion located outside the head and neck region must also be considered. One clue for detecting the primary lesion at imaging is the disruption of anatomic structures, which can help in identifying small mucosal lesions or submucosal tumors at each subsite. Additionally, fluorine 18 fluorodeoxyglucose PET/CT may help identify a primary tumor. These imaging approaches for identifying primary tumors enable prompt identification of the primary site and assist clinicians in making the correct diagnosis. © RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Liver functional assessment using time-associated change in the liver-to-spleen signal intensity ratio on enhanced magnetic resonance imaging: a retrospective study.

BACKGROUND: Liver-to-spleen signal intensity ratio (LSR) is evaluated by magnetic resonance imaging (MRI) in the hepatobiliary phase and has been reported as a useful radiological assessment of regional liver function. However, LSR is a passive (non-time-associated) assessment of liver function, not a dynamic (time-associated) assessment. Moreover, LSR shows limitations such as a dose bias of contrast medium and a timing bias of imaging. Previous studies have reported the advantages of time-associated liver functional assessment as a precise assessment of liver function. For instance, the indocyanine green (ICG) disappearance rate, which is calculated from serum ICG concentrations at multiple time points, reflects a precise preoperative liver function for predicting post-hepatectomy liver failure without the dose bias of ICG or the timing bias of blood sampling. The aim of this study was to develop a novel time-associated radiological liver functional assessment and verify its correlation with traditional liver functional parameters. METHODS: A total of 279 pancreatic cancer patients were evaluated to clarify fundamental time-associated changes to LSR in normal liver. We defined the time-associated radiological assessment of liver function, calculated using information on LSR from four time points, as the "LSR increasing rate" (LSRi). We then investigated correlations between LSRi and previous liver functional parameters. Furthermore, we evaluated how timing bias and protocol bias affect LSRi. RESULTS: Significant correlations were observed between LSRi and previous liver functional parameters such as total bilirubin, Child-Pugh grade, and albumin-bilirubin grade (P < 0.001 each). Moreover, considerably high correlations were observed between LSRi calculated using four time points and that calculated using three time points (r > 0.973 each), indicating that the timing bias of imaging was minimal. CONCLUSIONS: This study propose a novel time-associated radiological assessment, and revealed that the LSRi correlated significantly with traditional liver functional parameters. Changes in LSR over time may provide a superior preoperative assessment of regional liver function that is better for predicting post-hepatectomy liver failure than LSR using the hepatobiliary phase alone.

Neoadjuvant S-1 With Concurrent Radiotherapy Followed by Surgery for Borderline Resectable Pancreatic Cancer: A Phase II Open-label Multicenter Prospective Trial (JASPAC05).

OBJECTIVE: This study assessed whether neoadjuvant chemoradiotherapy (CRT) with S-1 increases the R0 resection rate in BRPC. SUMMARY OF BACKGROUND DATA: Although a multidisciplinary approach that includes neoadjuvant treatment has been shown to be a better strategy for BRPC than upfront resection, a standard treatment for BRPC has not been established. METHODS: A multicenter, single-arm, phase II study was performed. Patients who fulfilled the criteria for BRPC received S-1 (40 mg/m 2 bid) and concurrent radiotherapy (50.4 Gy in 28 fractions) before surgery. The primary endpoint was the R0 resection rate. At least 40 patients were required, with a 1-sided α = 0.05 and ß = 0.05 and expected and threshold values for the primary endpoint of 30% and 10%, respectively. RESULTS: Fifty-two patients were eligible, and 41 were confirmed to have definitive BRPC by a central review. CRT was completed in 50 (96%) patients and was well tolerated. The rate of grade 3/4 toxicity with CRT was 43%. The R0 resection rate was 52% among the 52 eligible patients and 63% among the 41 patients who were centrally confirmed to have BRPC. Postoperative grade III/IV adverse events according to the Clavien-Dindo classification were observed in 7.5%. Among the 41 centrally confirmed BRPC patients, the 2-year overall survival rate and median overall survival duration were 58% and 30.8 months, respectively. CONCLUSIONS: S-1 and concurrent radiotherapy seem to be feasible and effective at increasing the R0 resection rate and improving survival in patients with BRPC. TRIAL REGISTRATION: UMIN000009172.

Imaging of Malignant Minor Salivary Gland Tumors of the Head and Neck.

Minor salivary gland carcinomas (MSGCs) are nonminor tumors in the head and neck region and account for about half of all salivary gland carcinomas. Imaging evaluation based on the anatomy of minor salivary and mucous glands in the head and neck region as well as invasion patterns in each site helps in identifying optimal treatment modalities and planning suitable treatment strategies. MSGCs can be divided radiologically into localized and invasive subtypes on the basis of the clinical utility of such categorization. Characteristic invasion patterns of the invasive type include deep submucosal extension, bone marrow infiltration, and perineural spread, which are difficult to assess clinically. MSGCs easily invade adjacent structures because of their submucosal location and may spread along the muscles, nerves, periosteum, and dura mater. Moreover, the tumor may spread into the bone marrow without obvious bone destruction. In addition to imaging classification, examining the anatomy and distribution of the minor salivary glands, including the palatal, lingual, buccal, labial, and retromolar glands, as well as other mucous glands, including the glands of the sinonasal cavity and nasopharynx, lacrimal glands, ceruminous glands, laryngeal glands, and tracheal glands, facilitates MSGC diagnosis and tumor extension assessment. The authors review the precise anatomy of the minor salivary and mucous glands in the head and neck region, discuss the MSGC imaging classifications, and describe how to evaluate the extent of MSGCs in each site on the basis of the imaging classification and invasion patterns. ©RSNA, 2020.

Radiation Dose Reduction for Computed Tomography Localizer Radiography Using an Ag Additional Filter.

OBJECTIVE: This study aimed to assess the potential of an Ag additional filter attached to the bow tie filter of a computed tomography (CT) scanner to reduce the radiation dose in CT localizer radiography. METHODS: Radiation doses in CT localizer radiography with Cu and Ag additional filters were evaluated based on dose measurements and Monte Carlo simulations. Image quality evaluations of an adult torso phantom were performed, and the automatic exposure control performance was evaluated in terms of the water-equivalent thickness estimated from CT localizer radiographs. RESULTS: With the Ag additional filter, effective doses were approximately 72% to 75% lower than those with the Cu additional filter. The image quality and water-equivalent thickness with the Ag additional filter were similar to those with the Cu additional filter. CONCLUSIONS: The Ag additional filter helped significantly reduce radiation doses in CT localizer radiography while maintaining image quality and performance.

Relationship between surgical R0 resectability and findings of peripancreatic vascular invasion on CT imaging after neoadjuvant S-1 and concurrent radiotherapy in patients with borderline resectable pancreatic cancer.

BACKGROUND: Borderline resectable pancreatic cancer (BRPC) is frequently associated with positive surgical margins and a poor prognosis because the tumor is in contact with major vessels. This study evaluated the relationship between the margin-negative (R0) resection rate and findings indicating peripancreatic vascular invasion on multidetector computed tomography (MDCT) imaging after neoadjuvant chemoradiotherapy (NACRT) in patients with BRPC. METHODS: Twenty-nine BRPC patients who underwent laparotomy after neoadjuvant S-1 with concurrent radiotherapy were studied retrospectively. Peripancreatic major vessel invasion was evaluated based on the length of tumor-vessel contact on MDCT. The R0 resection rates were compared between the progression of vascular invasion (PVI) group and the non-progression of vascular invasion (NVI) group. RESULTS: There were 3 patients with partial responses (10%), 25 with stable disease (86%), and 1 with progressive disease (3%) according to the RECISTv1.1 criteria. Regarding vascular invasion, 9 patients (31%) were classified as having PVI, and 20 patients (69%) were classified as having NVI. Of the 29 patients, 27 (93%) received an R0 resection, and all the PVI patients received an R0 resection (9/9; R0 resection rate = 100%) while 90% (18/20) of the NVI patients underwent an R0 resection. The exact 95% confidence interval of risk difference between those R0 resection rates was - 10.0% [- 31.7-20.4%]. CONCLUSIONS: Patients with BRPC after NACRT achieved high R0 resection rates regardless of the vascular invasion status. BRPC patients can undergo R0 resections unless progressive disease is observed after NACRT. TRIAL REGISTRATION: UMIN-CTR, UMIN000009172 . Registered 23 October 2012.

Enhanced tumor response to radiotherapy after PD-1 blockade in metastatic gastric cancer.

BACKGROUND: Immune checkpoint inhibitors may enhance the efficacy of radiotherapy (RT) in cancer treatment but the effect remains unknown in metastatic gastric cancer (mGC). This study aimed to compare the tumor shrinkage by palliative RT for mGC patients with or without previous exposure to anti-PD-1 therapy. METHODS: Data of 36 mGC patients who had received palliative RT from April 2013 to May 2019 were analyzed. Primary tumor responses were evaluated through a volumetric measurement-based method using computed tomography (CT) and endoscopic responses were evaluated in patients who underwent endoscopy before and after RT. Tumor microenvironment (TME) immune status was investigated by analyzing tumor-infiltrating lymphocytes by flow cytometry. RESULTS: Among 36 patients, 18 had previous exposure to anti-PD-1 before RT showing no significant differences in baseline characteristics with the other 18 patients without exposure to anti-PD-1 treatment. Tumor responses were observed in 28% (5/18) and none (0/18) in the anti-PD-1-exposed vs. naïve group, respectively (P = 0.045). Five out of eight patients in the anti-PD-1-exposed group, who underwent endoscopy after RT showed partial response, but none in the anti-PD-1-naïve patients showed response (P = 0.026). Increase in the CD8+ T cell/effector regulatory T cell ratio in TILs after anti-PD-1 therapy was noted in three responders to RT, but not in the other three non-responders. CONCLUSIONS: Prior exposure to anti-PD-1 therapy increases tumor response to RT. Immune profiling suggests that anti-PD-1 therapy may enhance the efficacy of RT by immunoactivation in the TME.

Relationship between pancreatic thickness and staple height is relevant to the occurrence of pancreatic fistula after distal pancreatectomy.

BACKGROUND: A triple-row stapler is widely used to divide the pancreas in distal pancreatectomy (DP). However, the selection criteria of the stapler cartridge to prevent postoperative pancreatic fistula (POPF) remain unclear. The objective of this study was to determine if factors concerning pancreatic thickness or staple size affect POPF after DP. METHODS: Datasets of patients from the Mayo Clinic and National Cancer Center Hospital East who underwent DP using a triple-row stapler were merged. Risk of POPF was analyzed using clinicopathological variables, including data for pancreatic thickness and staple height. A compression index was defined as the designated staple height (mm) after closure divided by the pancreatic thickness (mm). RESULTS: Among the 277 patients, POPF occurred in 65 (23%) patients. The median pancreatic thickness was 13.7 mm and the median compression index was 0.137. Multivariable logistic models showed that a greater pancreatic thickness (odds ratio, 1.190, P < 0.001) and a compression index ≤0.160 (odds ratio, 4.754, P < 0.001) were independently related with POPF. CONCLUSION: In patients undergoing DP using a triple-row stapler, the thickness of the pancreas was related with the occurrence of POPF. Selection of the stapler cartridge with a compression index of ≤0.160 may reduce the occurrence of POPF.

Dual Gene Repertoires for Larval and Adult Shells Reveal Molecules Essential for Molluscan Shell Formation.

Molluscan shells, mainly composed of calcium carbonate, also contain organic components such as proteins and polysaccharides. Shell organic matrices construct frameworks of shell structures and regulate crystallization processes during shell formation. To date, a number of shell matrix proteins (SMPs) have been identified, and their functions in shell formation have been studied. However, previous studies focused only on SMPs extracted from adult shells, secreted after metamorphosis. Using proteomic analyses combined with genomic and transcriptomic analyses, we have identified 31 SMPs from larval shells of the pearl oyster, Pinctada fucata, and 111 from the Pacific oyster, Crassostrea gigas. Larval SMPs are almost entirely different from those of adults in both species. RNA-seq data also confirm that gene expression profiles for larval and adult shell formation are nearly completely different. Therefore, bivalves have two repertoires of SMP genes to construct larval and adult shells. Despite considerable differences in larval and adult SMPs, some functional domains are shared by both SMP repertoires. Conserved domains include von Willebrand factor type A (VWA), chitin-binding (CB), carbonic anhydrase (CA), and acidic domains. These conserved domains are thought to play crucial roles in shell formation. Furthermore, a comprehensive survey of animal genomes revealed that the CA and VWA-CB domain-containing protein families expanded in molluscs after their separation from other Lophotrochozoan linages such as the Brachiopoda. After gene expansion, some family members were co-opted for molluscan SMPs that may have triggered to develop mineralized shells from ancestral, nonmineralized chitinous exoskeletons.

Impact of pancreaticoduodenal arcade dilation on postoperative outcomes after pancreaticoduodenectomy.

BACKGROUND: The aim of this study was to investigate the impact of pancreaticoduodenal arcade (PDA) dilation on postoperative outcomes after pancreaticoduodenectomy. METHODS: Consecutive patients submitted to pancreaticoduodenectomy between 2008 and 2016 underwent preoperative multi-detector computed tomography, the images of which were re-reviewed. The patients were categorized according to the grade of PDA dilation into 3 groups (remarkably-dilated, slightly-dilated, and non-dilated). RESULTS: Among the 443 patients, 25 patients (5.6%) were categorized as remarkably-dilated PDA and 24 patients (5.4%) as having slightly-dilated PDA. The patients with remarkably-dilated PDA had undergone pancreaticoduodenectomy with additional surgical maneuvers to restore celiac arterial flow as needed, and had an uneventful postoperative recovery relative to those with non-dilated PDA. In contrast, patients with slightly-dilated PDA underwent only pancreaticoduodenectomy without additional surgical maneuvers, and developed clinically relevant postoperative pancreatic fistula (POPF) more frequently than those with non-dilated PDA (42% vs. 21%, P = 0.021). Moreover, slightly-dilated PDA was shown to be an independent risk factor for clinically relevant POPF (odds ratio = 2.719, P = 0.042). DISCUSSION: For patients with PDA dilation requiring pancreaticoduodenectomy, a preoperative evaluation of the vascular anatomy, intraoperative assessment of the celiac arterial flow, and additional surgical maneuvers might be necessary to reduce the risk of postoperative complications.

Transarterial (Chemo)Embolization for Liver Metastases in Patients with Neuroendocrine Tumors.

OBJECTIVE: The aim of this study was to evaluate the safety and efficacy of transarterial (chemo)embolization [TA(C)E] for the control of liver metastasis in patients with neuroendocrine tumors (NETs). METHODS: In this retrospective study, we enrolled 43 patients with metastatic NETs who had been treated with TA(C)E between December 1999 and June 2013 at the National Cancer Center Hospital, Tokyo or the National Cancer Center Hospital East, Kashiwa. We assessed tumor response, time to treatment failure (TTF), overall survival (OS), and frequency of adverse events in these patients, and attempted to identify predictors of TTF. RESULTS: The site of the primary tumor was the pancreas in 29 patients (67%), the gastrointestinal tract in 11 patients (26%), and unknown in 3 patients (7%). Response rate, disease control rate, median TTF, and median OS were 56%, 96%, 24.7 months, and 86.1 months, respectively. No significant predictors of TTF could be identified. While 3 patients developed serious adverse events (including liver abscess in 2 patients and acute renal failure in 1 patient), the adverse events were well tolerated in all other patients. CONCLUSION: TA(C)E appears to be effective and feasible for controlling the liver metastases in patients with NETs.

A Phase I/II trial of continuous hepatic intra-arterial infusion of 5-fluorouracil, mitoxantrone and cisplatin for advanced hepatocellular carcinoma.

BACKGROUND: The aim of this study was to investigate the dose-limiting toxicities (DLTs) and determine the recommended doses in the Phase I part of the study, and to evaluate the efficacy and toxicity in the Phase II part, of continuous hepatic intra-arterial infusion therapy with 5-fluorouracil, mitoxantrone and cisplatin (FMP therapy) in patients with advanced hepatocellular carcinoma (HCC). METHODS: Forty-five patients with advanced HCC were enrolled. The therapy consisted of continuous intra-arterial infusion of 5-fluorouracil from Day 1 through Day 5, and intra-arterial administration of mitoxantrone and cisplatin on Day 1 [5-fluorouracil/mitoxantrone/cisplatin (mg/m2): Level 1; 400/4/60, Level 2; 400/6/60, Level 3; 500/6/60]. RESULTS: In the Phase I part of the study, one of the six patients at Level 1 developed DLTs, including Grade 3 pulmonary embolism, while none of the patients at either Level 2 or Level 3 exhibited any DLTs. In the Phase II part, at Level 3, 36 patients were enrolled. Nine patients (25%) showed partial response, representing a response rate of 25% (95% confidence interval: 12-42%). The overall median survival time, 1-year survival rate and median progression-free survival time were 11.3 months, 46.9% and 7.0 months, respectively. The main Grade 3 or 4 hematological and non-hematological toxicities were leukopenia (36%), neutropenia (39%), thrombocytopenia (19%), and elevated serum aspartate aminotransferase (22%), elevated serum alanine aminotransferase (14%) and occlusion of hepatic artery (22%), respectively. CONCLUSION: Hepatic intra-arterial infusion therapy of FMP could not demonstrate a favorable tumor response and overall survival in patients with advanced HCC.

Pancreatic perfusion data and post-pancreaticoduodenectomy outcomes.

BACKGROUND: Precise risk assessment for postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD) may be facilitated using imaging modalities. Computed tomography perfusion (CTP) of the pancreas may represent histologic findings. This study aimed to evaluate the utility of CTP data for the risk of POPF after PD, in relation to histologic findings. METHODS: Twenty patients who underwent preoperative pancreatic CTP measurement using 320-detector row CT before PD were investigated. Clinicopathologic findings, including CTP data, were analyzed to assess the occurrence of POPF. In addition, the correlation between CTP data and histologic findings was evaluated. RESULTS: POPF occurred in 11 cases (grade A, 6; grade B, 5; and grade C, 0). In CTP data, both high arterial flow (AF) and short mean transit time (MTT) were related to POPF occurrence (P = 0.001, P = 0.001). AF was negatively correlated with fibrosis in the pancreatic parenchyma (r = -0.680), whereas MTT was positively correlated with fibrosis (r = 0.725). AF >80 mL/min/100 mL and MTT <16 s showed high sensitivity, specificity, positive predictive value, and negative predictive value (80.0%, 100.0%, 100.0%, and 83.3%, respectively) for the occurrence of POPF. CONCLUSIONS: CTP data for the pancreas were found to be correlated with the occurrence of POPF after PD. Alterations in the blood flow to the remnant pancreas may reflect histological changes, including fibrosis in the pancreatic stump, and influence the outcome after PD. CTP may thus facilitate objective and quantitative risk assessment of POPF after PD.

Evaluation of a near-infrared-type contrast medium extravasation detection system using a swine model.

PURPOSE: To refine the development and evaluate the near-infrared (NIR) extravasation detection system and its ability to detect extravasation during a contrast-enhanced computed tomography (CT) examination. MATERIALS AND METHODS: The NIR extravasation detection system projects the NIR light through the surface of the human skin then, using its sensory system, will monitor the changes in the amount of NIR that reflected, which varies based on absorption properties.Seven female pigs were used to evaluate the contrast media extravasation detection system, using a 20-gauge intravenous catheter, when injected at a rate of 1 mL/s into 4 different locations just under the skin in the thigh section. Using 3-dimensional CT images, we evaluated the extravasations between time and volume, depth and volume, and finally depth and time to detect. RESULTS: We confirmed that the NIR light, 950-nm wavelength, used by the extravasation detection system is well absorbed by contrast media, making changes easy to detect. The average time to detect an extravasation was 2.05 seconds at a depth of 2.0 mm below the skin with a volume of 1.3 mL, 2.57 seconds at a depth between 2.1 and 5 mm below the skin and a volume of 3.47 mL, 10.5 seconds for depths greater than 5.1 mm and a volume of 11.1 mL. The detection accuracy was significantly deteriorated when the depth exceeded 5.0 mm (Tukey-Kramer, P < 0.05) CONCLUSIONS: The extravasation system detection system that is using NIR has a high level of detection sensitivity. The sensitivity enables the system to detect extravasation at depths less than 2 mm with a volume of 1.5 mL and at depths less than 5 mm with a volume of 3.5 mL. The extravasation detection system could be suitable for use during examinations.

Computed tomography-guided percutaneous needle biopsy for middle mediastinal tumors with retroaortic paravertebral approach: A case report.

A 74-year-old man was referred to our hospital for a close examination of a mediastinal mass. Contrast-enhanced CT showed a middle mediastinal tumor. We planned to perform a CT-guided percutaneous needle biopsy of the tumor using a retroaortic paravertebral approach to avoid transpulmonary puncture. A coaxial blunt-tip needle with a side hole was used to create space in the mediastinum and avoid azygos vein injury. After injecting normal saline, a blunt-tip needle was advanced through the space between the aorta and the vertebral body to the anterior surface of the tumor, and tissue was obtained. The patient was discharged the following day with no complications. For percutaneous middle mediastinal tumor biopsy, the retroaortic paravertebral approach may be a safe, effective route.

Patient characteristics and procedural and safety outcomes of percutaneous transesophageal gastro-tubing: A nationwide database study in Japan.

BACKGROUND: Percutaneous transesophageal gastro-tubing (PTEG) is an alternative interventional procedure in cases where gastrostomy is not feasible. However, the safety and complication rates of PTEG have not yet been evaluated. We aimed to describe the characteristics of patients who underwent PTEG and investigate complications using a nationwide Japanese inpatient database. METHODS: In this retrospective cohort study, we used the Diagnosis Procedure Combination database in Japan to identify patients who underwent PTEG from April 2012 to March 2020. The outcomes were the occurrence of complications, invasive treatment within 7 days after PTEG, and tube replacement within 14 days after PTEG. We statistically compared patient background, complication rates, and outcomes using PTEG indications. RESULTS: A total of 3,684 patients underwent PTEG, which was performed in 1,455 patients for decompression and 2,193 patients for feeding. The patients' mean age was 73.1 years, and 62.1% were men. More patients in the decompression group had cancer than those in the feeding group. The overall number of complications was 47 cases (1.3%). The most common treatment administered after PTEG was red blood cell transfusion (3.9%), followed by early tube replacement (3.3%). As invasive treatments for PTEG complications, percutaneous drainage and transcatheter arterial embolization were required in 4 and 1 cases, respectively, and no cases required surgery. CONCLUSION: We performed a descriptive study on PTEG using a nationwide database in Japan. This study also showed a low complication rate after PTEG in the real world. Our findings provide practical information on the safety of PTEG in Japan.