FDG uptake in the cervical muscles after neck dissection: imaging features and postoperative natural course on 18F­FDG­PET/CT.

PURPOSE: This study aimed to assess the imaging features and postoperative natural course of 18F-fluorodeoxyglucose (FDG) uptake in the cervical muscles after neck dissection. MATERIALS AND METHODS: This study included 83 patients who underwent preoperative and postoperative 18F-FDG-PET/CT and were diagnosed with head and neck malignancy after neck dissection. Postoperative 18F-FDG-PET/CT was performed within 5 years after neck dissection. Preoperative and postoperative FDG uptake of the trapezius, sternocleidomastoid, scalene, pectoralis major, and deltoid muscles was visually assessed. Increased postoperative uptake was visually defined as higher postoperative FDG uptake than the preoperative one in the corresponding muscle. The maximum standardized uptake value (SUVmax) was measured in cases with increased postoperative uptakes. RESULTS: Increased postoperative uptakes were observed in 43 patients (52%). The trapezius (31/83, 37%), sternocleidomastoid (19/83, 23%), and scalene (12/83, 14%) muscles were involved, as opposed to the pectoralis major and deltoid muscles were not. Increased postoperative uptakes were observed on the dissected side in all 43 patients. Significant differences between SUVmax estimated from the mixed-effects model and postoperative months were observed in the trapezius muscle (Coefficient (ß) = -0.038; 95% confidence interval (CI): [-0.047, -0.028]; p < 0.001) and sternocleidomastoid muscle (ß = -0.015; 95% CI: [-0.029, -0.001]; p = 0.046). CONCLUSIONS: Increased postoperative uptakes in the cervical muscles were observed on the dissected side in approximately half of the patients after neck dissection. The SUVmax in the trapezius and sternocleidomastoid muscles decreased after surgery over time.

Prognostic value of radiological T category using conventional MRI in patients with oral tongue cancer: comparison with pathological T category.

PURPOSE: This study aimed to compare the radiological tumor (T)-category using multiparametric MRI with the pathological T category in patients with oral tongue squamous cell carcinoma (OTSCC) and to examine which is a better predictor of prognosis. METHODS: This retrospective study included 110 consecutive patients with surgically resected primary OTSCC who underwent preoperative contrast-enhanced MRI. T categories determined by maximum diameter and depth of invasion were retrospectively assessed based on the pathological specimen and multiparametric MRI. The MRI assessment included the axial and coronal T1-weighted image (T1WI), axial T2-weighted image (T2WI), coronal fat-suppressed T2WI, and axial and coronal fat-suppressed contrast-enhanced T1WI (CET1WI). Axial and coronal CET1WI measurements were divided into two groups: measurements excluding peritumoral enhancement (MEP) and measurements including peritumoral enhancement. The prognostic values for recurrence and disease-specific survival after radiological and pathological T categorization of cases into T1/T2 and T3/T4 groups were compared. RESULTS: The T category of MEP on coronal CET1WI was the most relevant prognostic factor for recurrence [hazard ratio (HR) = 3.30, p = 0.001] and the HR was higher than the HR for pathological assessment (HR = 2.26, p = 0.026). The T category determined by MEP on coronal CET1WI was also the most relevant prognostic factor for disease-specific survival (HR = 3.12, p = 0.03), and the HR was higher than the HR for pathological assessment (HR = 2.02, p = 0.20). CONCLUSION: The T category determined by MEP on the coronal CET1WI was the best prognostic factor among all radiological and pathological T category measurements.

Pancreatic cancer detection with dual-energy CT: diagnostic performance of 40 keV and 70 keV virtual monoenergetic images.

PURPOSE: To compare the diagnostic performance of 40 keV and 70 keV virtual monoenergetic images (VMIs) generated from dual-energy CT in the detection of pancreatic cancer. METHODS: This retrospective study included patients who underwent pancreatic protocol dual-energy CT from January 2019 to August 2022. Four radiologists (1-11 years of experience), who were blinded to the final diagnosis, independently and randomly interpreted 40 keV and 70 keV VMIs and graded the presence or absence of pancreatic cancer. For each image set (40 keV and 70 keV VMIs), the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated. The diagnostic performance of each image set was compared using generalized estimating equations. RESULTS: Overall, 137 patients (median age, 71 years; interquartile range, 63-78 years; 77 men) were included. Among them, 62 patients (45%) had pathologically proven pancreatic cancer. The 40 keV VMIs had higher specificity (75% vs. 67%; P < .001), PPV (76% vs. 71%; P < .001), and accuracy (85% vs. 81%; P = .001) than the 70 keV VMIs. On the contrary, 40 keV VMIs had lower sensitivity (96% vs. 98%; P = .02) and NPV (96% vs. 98%; P = .004) than 70 keV VMIs. However, the diagnostic confidence in patients with (P < .001) and without (P = .001) pancreatic cancer was improved in 40 keV VMIs than in 70 keV VMIs. CONCLUSIONS: The 40 keV VMIs showed better diagnostic performance in diagnosing pancreatic cancer than the 70 keV VMIs, along with higher reader confidence.

Intestinal Atp8b1 dysfunction causes hepatic choline deficiency and steatohepatitis.

Choline is an essential nutrient, and its deficiency causes steatohepatitis. Dietary phosphatidylcholine (PC) is digested into lysoPC (LPC), glycerophosphocholine, and choline in the intestinal lumen and is the primary source of systemic choline. However, the major PC metabolites absorbed in the intestinal tract remain unidentified. ATP8B1 is a P4-ATPase phospholipid flippase expressed in the apical membrane of the epithelium. Here, we use intestinal epithelial cell (IEC)-specific Atp8b1-knockout (Atp8b1IEC-KO) mice. These mice progress to steatohepatitis by 4 weeks. Metabolomic analysis and cell-based assays show that loss of Atp8b1 in IEC causes LPC malabsorption and thereby hepatic choline deficiency. Feeding choline-supplemented diets to lactating mice achieves complete recovery from steatohepatitis in Atp8b1IEC-KO mice. Analysis of samples from pediatric patients with ATP8B1 deficiency suggests its translational potential. This study indicates that Atp8b1 regulates hepatic choline levels through intestinal LPC absorption, encouraging the evaluation of choline supplementation therapy for steatohepatitis caused by ATP8B1 dysfunction.

Prognostic Factors of Pretreatment Magnetic Resonance Imaging for Predicting Clinical Outcome in Patients With Parotid Gland Cancer.

PURPOSE: This study aimed to assess the utility of pretreatment magnetic resonance imaging (MRI) in predicting the clinical outcomes of patients with parotid gland cancer. METHODS: A total of 43 patients with histopathologically confirmed primary parotid gland cancer, who underwent pretreatment MRI, were enrolled in this study. All images were retrospectively reviewed, and MRI features were evaluated as possible prognostic factors influencing the progression-free survival (PFS) using the Kaplan-Meier method and Cox proportional hazards regression model. Cox regression analysis was used to estimate the hazard ratios (HRs) with 95% confidence interval (95% CI) values. RESULTS: Kaplan-Meier survival analysis showed that old age (>73 years, P < 0.01), large maximum tumor diameter (>33 mm, P < 0.01), low apparent diffusion coefficient value (≤1.29 ×10 -3 mm 2 /s, P < 0.01), ill-defined margin ( P < 0.01), skin invasion ( P < 0.01), regional nodal metastasis ( P < 0.01), heterogeneous enhancement ( P < 0.05), and high signal intensity ratio on gadolinium-enhanced fat-suppressed T1-weighted images (>2.017, P < 0.05) were significant predictors of worse PFS. Cox proportional hazards regression analysis revealed that regional nodal metastasis (HR, 32.02; 95% CI, 6.42-159.84; P < 0.01) and maximum tumor diameter (HR, 1.04; 95% CI, 1.01-1.08; P < 0.05) were independent predictors of PFS. CONCLUSION: Pretreatment MRI parameters could be prognostic factors of patients with parotid gland cancer. In particular, the maximum tumor diameter and regional nodal metastasis, which were closely associated with T and N classifications, were important prognostic factors in predicting the PFS.

MRI findings of sporadic/simple lymphoepithelial cyst of the parotid gland.

PURPOSE: This study aimed to determine the MRI features of sporadic/simple lymphoepithelial cyst (SLEC) of the parotid gland. METHODS: Ten patients (seven men, three women; mean age, 60 years; age range, 38-77 years) with histopathologically and clinically proven SLEC of the parotid gland who underwent MRI before surgical resection were enrolled in this study. No enrolled patient had HIV infection or Sjögren syndrome. MRI findings of SLEC were retrospectively assessed. RESULTS: We confirmed 10 SLECs larger than 10 mm with a mean maximum diameter of 26.6 mm (range, 12-42 mm). Nine patients (90%) had a single cyst, and one (10%) had a large cyst accompanied by small cysts (<10 mm) within the ipsilateral parotid gland. Eight SLECs (80%) were unilocular, and two (20%) were bilocular, with complete septa. Among seven SLECs (70%) with internal septa, five unilocular SLECs (50%) had incomplete septa. Six SLECs (60%) had eccentric cyst wall thickening, and five (50%) were surrounded by small solid nodules that were isointense relative to lymph node. On T1-weighted images, all cyst contents were homogeneously hyperintense relative to cerebrospinal fluid. CONCLUSION: SLECs of the parotid gland are usually single unilocular lesions. Internal septa, eccentric cyst wall thickening, and small solid nodules surrounding the lesion were often observed. Cyst contents are always homogeneously hyperintense on T1-weighted images.

Prospective study examining the probability of cerebral fat embolism based on magnetic resonance imaging.

Purpose: Cerebral fat embolism (CFE) is a rare syndrome caused by the embolization of fat particles into the brain circulation. This prospective single-center observational study investigated the incidence of CFE in long-bone or pelvic fractures based on magnetic resonance imaging (MRI) findings. The purpose of this study was to investigate the incidence of CFE by MRI findings with or without symptoms suggestive of CFE. Methods: Eligible patients were consecutive, aged 15 years or older, with high-energy traumas, including pelvic or femur fractures. Excluded patients were those who died, could not undergo MRI resulting from medical conditions, or had insufficient mental capacity and no consultee to provide consent. The MRI was scheduled within 4 weeks of the injury, and the images were reviewed by one of the three neuroradiologists who were unaware of the patient's clinical information. Patient data regarding demographics, preceding trauma, injury severity score (ISS), presentation and examination timing of MRI, management including surgery, and outcome were collected. Results: Sixty-two patients were recruited, and three patients were excluded. All patients were injured by blunt trauma. The median patient age was 44 years. The median ISS was 13, and 53 patients needed surgical fixation. There were 22 patients with long-bone fractures, all of whom received external fixation or intramedullary nailing on admission day. MRI was performed after a median hospital day of 18 days. Using MRI imaging, three (5.0%) patients were diagnosed with CFE, and three patients were suspected of CFE. Conclusions: This is the first study to prospectively examine the probability of CFE based on MRI. Since fat embolism syndrome (FES) is confirmed in patients without clinical symptoms, CFE may be more common in patients with trauma than currently believed. Therefore, studies to determine the diagnostic criteria combined with symptoms, MRI, or other objective findings are required in the future.

Determination of arterial invasion in pancreatic ductal adenocarcinoma: what is the best diagnostic criterion on CT?

OBJECTIVES: To investigate the diagnostic performance and interobserver variability in the determination of arterial invasion in pancreatic ductal adenocarcinoma (PDAC) and determine the best CT imaging criterion. METHODS: We retrospectively evaluated 128 patients with PDAC (73 men and 55 women) who underwent preoperative contrast-enhanced CT. Five board-certified radiologists (expert) and four fellows (non-expert]) independently assessed the arterial invasion (celiac, superior mesenteric, splenic, and common hepatic arteries) using a 6-point score: 1, no tumor contact; 2, hazy attenuation ≤ 180°; 3, hazy attenuation > 180°; 4, solid soft tissue contact ≤ 180°; 5, solid soft tissue contact > 180°; and 6, contour irregularity. ROC analysis was performed to evaluate the diagnostic performance and determine the best diagnostic criterion for arterial invasion, with pathological or surgical findings as references. Interobserver variability was assessed using Fleiss's ĸ statistics. RESULTS: Among the 128 patients, 35.2% (n = 45/128) received neoadjuvant treatment (NTx). Solid soft tissue contact ≤ 180° was the best diagnostic criterion for arterial invasion as defined by the Youden Index both in patients who did and did not receive NTx (sensitivity, 100% vs. 100%; specificity, 90% vs. 93%; and AUC, 0.96 vs. 0.98, respectively). Interobserver variability among the non-expert was not inferior to that among the expert (ĸ = 0.61 vs 0.61; p = .39 and ĸ = 0.59 vs 0.51; p < .001 in patients treated with and without NTx, respectively). CONCLUSIONS: Solid soft tissue contact ≤ 180° was the best diagnostic criterion for the determination of arterial invasion in PDAC. Considerable interobserver variability was seen among the radiologists. KEY POINTS: • Solid soft tissue contact ≤ 180° was the best diagnostic criterion for the determination of arterial invasion in pancreatic ductal adenocarcinoma. • Interobserver agreement among non-expert radiologists was almost comparable to that among expert radiologists.

Intranodal dynamic contrast-enhanced CT lymphangiography and dynamic contrast-enhanced MR lymphangiography in microminipig.

OBJECTIVES: To evaluate the feasibility and image quality of intranodal dynamic contrast-enhanced CT lymphangiography (DCCTL) and dynamic contrast-enhanced MR lymphangiography (DCMRL) in microminipigs. METHODS: Our institution's committee for animal research and welfare provided approval. Three microminipigs underwent DCCTL and DCMRL after inguinal lymph node injection of 0.1 mL/kg contrast media. Mean CT values on DCCTL and signal intensity (SI) on DCMRL were measured at the venous angle and thoracic duct (TD). The contrast enhancement index (CEI; increase in CT values pre- to post-contrast) and signal intensity ratio (SIR; SI of lymph divided by SI of muscle) were evaluated. The morphologic legibility, visibility, and continuity of lymphatics were qualitatively evaluated using a 4-point scale. Two microminipigs underwent DCCTL and DCMRL after lymphatic disruption and the detectability of lymphatic leakage was evaluated. RESULTS: The CEI peaked at 5-10 min in all microminipigs. The SIR peaked at 2-4 min in two microminipigs and at 4-10 min in one microminipig. The peak CEI and SIR values were 235.6 HU and 4.8 for venous angle, 239.4 HU and 2.1 for upper TD, and 387.3 HU and 2.1 for middle TD. The visibility and continuity of upper-middle TD scores were 4.0 and 3.3-3.7 for DCCTL, and 4.0 and 4.0 for DCMRL. In the injured lymphatic model, both DCCTL and DCMRL demonstrated lymphatic leakage. CONCLUSIONS: DCCTL and DCMRL in a microminipig model enabled excellent visualization of central lymphatic ducts and lymphatic leakage, indicating the research and clinical potential of both modalities. KEY POINTS: • Intranodal dynamic contrast-enhanced computed tomography lymphangiography showed a contrast enhancement peak at 5-10 min in all microminipigs. • Intranodal dynamic contrast-enhanced magnetic resonance lymphangiography showed a contrast enhancement peak at 2-4 min in two microminipigs and at 4-10 min in one microminipig. • Both intranodal dynamic contrast-enhanced computed tomography lymphangiography and dynamic contrast-enhanced magnetic resonance lymphangiography demonstrated the central lymphatic ducts and lymphatic leakage.

Current status of diffusion-weighted imaging in differentiating parotid tumors.

Recently, diffusion-weighted imaging (DWI) is an essential magnetic resonance imaging (MRI) protocol for head and neck imaging in clinical practice as it plays an important role in lesion detection, tumor extension evaluation, differential diagnosis, therapeutic effect prediction, therapy evaluation, and recurrence diagnosis. Especially in the parotid gland, several studies have already attempted to achieve accurate differentiation between benign and malignant tumors using DWI. A conventional single-shot echo-planar-based DWI is widely used for head and neck imaging, whereas advanced DWI sequences, such as intravoxel incoherent motion, diffusion kurtosis imaging, periodically rotated overlapping parallel lines with enhanced reconstruction, and readout-segmented echo-planar imaging (readout segmentation of long variable echo-trains), have been used to characterize parotid tumors. The mean apparent diffusion coefficient values are easily measured and useful for assessing cellularity and histological characteristics, whereas advanced image analyses, such as histogram analysis, texture analysis, and machine and deep learning, have been rapidly developed. Furthermore, a combination of DWI and other MRI protocols has reportedly improved the diagnostic accuracy of parotid tumors. This review article summarizes the current state of DWI in differentiating parotid tumors.

Different CT imaging findings between histological subtypes in patients with primary thyroid lymphoma.

PURPOSE: This study evaluates the differences in CT imaging findings between diffuse large B cell lymphoma (DLBCL) and mucosa-associated lymphoid tissue (MALT) lymphoma of the thyroid gland. METHODS: This study included 18 patients with histopathologically confirmed primary thyroid lymphoma (nine with DLBCL and nine with MALT lymphoma). All patients underwent pretreatment CT imaging. We retrospectively reviewed all images and compared the imaging findings between the two pathologies. RESULTS: The maximum diameter was significantly greater in DLBCL than in MALT lymphoma (67.7 ± 17.0 mm vs. 41.0 ± 27.2 mm, p < 0.01). Diffuse type (78% vs. 11%, p < 0.01), thickening of the isthmus (78% vs. 22%, p < 0.05), invasion of surrounding tissues (78% vs. 0%, p < 0.01), and regional lymphadenopathy (44% vs. 0%, p < 0.05) were more frequent in DLBCL than in MALT lymphoma. However, preserved peripheral thyroid tissue was more frequent in MALT lymphoma than in DLBCL (78% vs. 22%, p < 0.05). CONCLUSIONS: The maximum diameter, morphological patterns (diffuse or nodular type), thickening of the isthmus, invasion of surrounding tissues, regional lymphadenopathy, and preserved peripheral thyroid tissue were useful CT imaging features in differentiating DLBCL from MALT lymphoma of the thyroid gland.

MRI findings of epithelial-myoepithelial carcinoma of the parotid gland with radiologic-pathologic correlation.

PURPOSE: This study aimed to describe the MRI findings of epithelial-myoepithelial carcinoma (EMC) of the parotid gland. MATERIALS AND METHODS: Seven patients (four males and three females) aged 40-86 years (mean age, 64 years) with histologically proven EMC of the parotid gland who underwent surgical resection after preoperative MRI were enrolled. MRI images were retrospectively reviewed and contrasted with pathological findings. RESULTS: Five patients (71%) had predominantly solid lesions, and two (29%) had predominantly cystic lesions. All seven lesions had well-demarcated margins and capsules without the invasion of adjacent structures. The capsules were incomplete in five lesions (71%) and complete in two (29%). Four lesions (57%) exhibited a multinodular structure with internal septa. Cystic components were observed in three lesions (43%). On T1-weighted images, the solid components were frequently homogeneous (5/7, 71%), and demonstrated isointensity in five lesions (71%) and hypointensity in two (29%) relative to the spinal cord. On T2-weighted images, the solid components were usually heterogeneous (6/7, 86%), and demonstrated hyperintensity in five lesions (71%) and isointensity in two (29%) relative to the spinal cord. The mean apparent diffusion coefficient value of the solid components was 0.967 × 10-3 mm2/s. CONCLUSION: Parotid gland EMCs usually appeared as predominantly solid lesions with well-demarcated margins and capsules. A multinodular structure with internal septa was characteristics of EMCs.

Computed Tomography Imaging Findings for Predicting Histological Subtypes and Clinical Outcomes in Patients With Head and Neck Nodal Involvement of Diffuse Large B-Cell Lymphoma and Follicular Lymphoma.

OBJECTIVE: This study aimed to assess computed tomography (CT) imaging findings for predicting the histological subtypes and clinical outcomes in patients with head and neck nodal involvement of diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). METHODS: This retrospective study included 64 patients with histologically confirmed head and neck nodal lymphoma (43 with DLBCL and 21 with FL) who underwent pretreatment CT examinations. The CT imaging findings were retrospectively assessed and compared according to the 2 pathologies and their clinical outcomes. RESULTS: Multiplicity (86% vs 57%, P < 0.05), necrosis (44% vs 5%, P < 0.01), ill-demarcated margin (33% vs 0%, P < 0.01), and surrounding fat stranding (56% vs 14%, P < 0.01) were significantly more frequent in DLBCLs than in FLs. Multivariate logistic regression analysis revealed that necrosis was a significant factor for predicting the diagnosis of DLBCL (P < 0.01). Multiplicity (100% vs 67%, P < 0.01), bilaterality (44% vs 13%, P < 0.05), and surrounding fat stranding (69% vs 28%, P < 0.01) were significantly more frequent in the poor outcome group than in the good outcome group. Multivariate logistic regression analysis revealed that bilaterality and surrounding fat stranding were significant factors for predicting poor outcomes (P < 0.05). CONCLUSIONS: In patients with head and neck nodal lymphoma, necrosis was useful for predicting the diagnosis of DLBCL, whereas bilaterality and surrounding fat stranding were useful for predicting poor outcomes.

Accidental Insertion of a Piercing Needle in Tongue.

ABSTRACT: Tongue piercing causes various complications, including bleeding, pain and infection and it cause potential life-threatening complications. An 18-year-old woman presents with losing a needle in mouth. She attempted to perform tongue piercing using piercing needle by herself at home, and it was lost in mouth. The patient showed speech difficulty, but no active bleeding and edema of the floor of mouth. Computed tomography showed approximately 50 mm needle like structure in tongue. General anesthesia was performed with nasal intubation using video laryngoscope. The surgeon found the needle could be hold in the tongue by fingers. The needle in the tongue was holding by left fingers, and 10 mm skin incision was made by right hand. The needle tip was pushed to the incision line and it was removed. There was no bleeding immediate after needle removal. She could speak immediate after surgery. Two days after surgery, the patient discharged with no complications.

MR imaging findings for differentiating nonhemophilic hemosiderotic synovitis from diffuse-type tenosynovial giant cell tumor of the knee.

PURPOSE: To evaluate the differences in MR findings between nonhemophilic hemosiderotic synovitis (HS) and diffuse-type tenosynovial giant cell tumor (D-TGCT) of the knee. METHODS: This study included 13 patients with histopathologically confirmed intra-articular hemosiderin deposition of the knee (eight with nonhemophilic HS and five with D-TGCT) who underwent preoperative MR imaging including T2*-weighted images (T2*WI). We retrospectively reviewed the MR images and compared MR findings between the two pathologies. RESULTS: Lateral meniscus tear and lateral articular cartilage injury (88% vs. 20%, p < 0.05) and distribution in the suprapatellar bursa of the maximum thickness of T2* hypointense synovium (75% vs. 0%, p < 0.05) were significantly more frequent in nonhemophilic HS than in D-TGCT, respectively. Among patients who underwent contrast-enhanced imaging, all five patients with nonhemophilic HS showed minimal to mild enhancement of the thickened synovium with superficial linear enhancement, whereas all four patients with D-TGCT showed moderate to severe enhancement (p < 0.01). CONCLUSION: As compared with D-TGCT, lateral meniscus tear, lateral articular cartilage injury, lesser degree of contrast enhancement of the thickened synovium, and distribution in the suprapatellar bursa of the maximum thickness of T2* hypointense synovium were characteristic features of nonhemophilic HS.

Mandibular Fracture in a Patient Taking a Direct Oral Anticoagulant.

ABSTRACT: A 74-year-old man presented with hemorrhage from the mandible after an injury caused by a 5 × 3 × 3-cm metal square column flying from a 45-ton press machine that struck the right side of his face. He is a known atrial fibrillation patient and is on rivaroxaban, a direct oral anticoagulant. An approximately 8-cm Y-shaped wound with persistent hemorrhage was observed in the right mandible, and the mandible was displaced between the right mandibular canine and first premolar. Although the patient showed no dyspnea, the sublingual region showed a slight dark purple swelling; fiberoptic nasal intubation was performed. Computed tomography at 3.5 hours after the injury revealed a comminuted fracture of the right mandibular body, edema at the floor of the mouth, nasal cavity, upper pharynx to hypopharynx, and the pharyngeal airway around the endotracheal tube. Open reduction and internal fixation were performed. Rivaroxaban was started again 3 days after surgery.

Hypointense head and neck lesions on T2-weighted images: correlation with histopathologic findings.

PURPOSE: On T2-weighted images, most solid lesions exhibit nonspecific intermediate signal intensity, whereas most cystic lesions exhibit marked hyperintensity. In contrast, on T2-weighted images, a relatively small number of lesions exhibit hypointensity. This review aimed to differentiate, according to the histopathologic findings, head and neck lesions showing hypointensity on T2-weighted images. METHODS: In this review article, hypointense head and neck lesions on T2-weighted images are classified into the following nine categories: calcified or osseous lesions, granulomatous lesions, fibrous lesions, mucous- or proteincontaining lesions, hemosiderin-containing lesions, melanin-containing lesions, thyroglobulin-containing lesions, rapid blood flow, and air-filled spaces. CONCLUSION: Knowledge regarding hypointense head and neck lesions on T2-weighted images allows radiologists to make accurate differential diagnoses. Key points • Hypointense head and neck lesions on T2-weighted images include calcified or osseous lesions, granulomatous lesions, fibrous lesions, mucous- or protein-containing lesions, hemosiderin-containing lesions, melanin-containing lesions, thyroglobulin-containing lesions, rapid blood flow, and air-filled spaces. • Radiologists should recognize the hypointense head and neck lesions on T2-weighted images for the final correct diagnosis, resulting in appropriate patient management.

Dynamic contrast-enhanced computed tomography lymphangiography with intranodal injection of water-soluble iodine contrast media in microminipig: imaging protocol and feasibility.

OBJECTIVES: To evaluate the optimal imaging protocol and the feasibility of intranodal dynamic contrast-enhanced computed tomography lymphangiography (DCCTL) in microminipigs. METHODS: The Committee for Animal Research and Welfare provided university approval. Five female microminipigs underwent DCCTL after inguinal lymph node injection of 0.1 mL/kg of iodine contrast media at a rate of 0.3 mL/min with three different iodine concentrations: group 1, 75 mgI/mL; group 2, 150 mgI/mL; and group 3, 300 mgI/mL. The CT values of the venous angle, thoracic duct (TD), cisterna chyli, iliac lymphatic duct, and iliac lymph node were measured; increases in CT values pre- to post-contrast were assessed as the contrast-enhanced index (CEI). Multi-detector row CT (MDCT) and volume rendering images showing the highest CEI were qualitatively evaluated. RESULTS: The CEI of all lymphatics peaked at 5-10 min. The mean CEI of TD at 10 min of group 2 (193.0 HU) and group 3 (201.5 HU) were significantly higher than that of group 1 (70.7 HU) (p = 0.024). The continuity and overall diagnostic acceptability of all lymphatic system components were better in group 3 (3.6 and 3.0, respectively) than group 1 (2.6 and 1.6) and group 2 (3.0 and 2.6) (p = 0.249 and 0.204). CONCLUSIONS: The optimal imaging protocol for intranodal DCCTL could be dual-phase imaging at 5 and 10 min after the injection of 300 mgI/mL iodinated contrast media. DCCTL provided good images of lymphatics and is potentially feasible in clinical settings. KEY POINTS: • Dynamic contrast-enhanced computed tomography lymphangiography with intranodal injection of water-soluble iodine contrast media showed the highest enhancement of all lymphatics at scan delays of 5 and 10 min. • The optimal iodine concentration for intranodal dynamic contrast-enhanced computed tomography lymphangiography might be 300 mgI/mL. • Intranodal dynamic contrast-enhanced computed tomography lymphangiography provided good images of all the lymphatic system components and is potentially feasible in clinical settings.

Diagnostic ability of contrast-enhanced computed tomography for metastatic cervical nodes in head and neck squamous cell carcinomas: significance of additional coronal reconstruction images.

PURPOSE: To evaluate the significance of additional coronal reconstruction images in the diagnostic ability of contrast-enhanced computed tomography (CECT) for metastatic cervical nodes in patients with head and neck squamous cell carcinomas (HNSCC). MATERIAL AND METHODS: We retrospectively assessed 97 metastatic and 141 reactive histologically proven cervical nodes of 38 patients with HNSCC, who underwent CECT before neck dissection. Observer #1, an expert radiologist in head and neck imaging, and observer #2, a general radiologist, reviewed all CECT images. The observers first assessed the presence of nodal metastasis using axial CECT alone (A-CECT). Three days later, they reassessed its presence using combined axial and coronal CECT (A&C-CECT). RESULTS: The sensitivity of A-CECT vs. A&C-CECT was 73.2% vs. 75.3% for observer #1 (p = 0.73) and 69.1% vs. 69.1% for observer #2 (p = 1.00), respectively. The specificity of A-CECT versus A&C-CECT was 92.2% vs. 97.2% for observer #1 (p < 0.05) and 92.9% vs. 95.7% for observer #2 (p = 0.22), respectively. The accuracy of A-CECT versus A&C-CECT was 84.5% vs. 88.2% for observer #1 (p < 0.05) and 83.2% vs. 85.3% for observer #2 (p = 0.30), respectively. The area under the curve (AUC) of A-CECT vs. A&C-CECT was 0.86 vs. 0.91 for observer #1 (p < 0.05) and 0.85 vs. 0.85 for observer #2 (p = 0.80), respectively. CONCLUSIONS: The specificity, accuracy, and AUC increased with the use of coronal images during the assessment by the expert radiologist. The appropriate use of coronal images allowed proper configuration recognition and improved diagnostic ability.

MR findings for differentiating decidualized endometriomas from seromucinous borderline tumors of the ovary.

PURPOSE: Decidualized endometriomas (DEs) and seromucinous borderline tumors (SMBTs) exhibit similar MR findings including markedly hyperintense mural nodules within endometriotic cysts on T2-weighted images. The present study aimed to assess the efficacy of MR imaging for differentiating between DEs and SMBTs of the ovary. MATERIALS AND METHODS: MR images of 8 DEs and 14 SMBTs were retrospectively assessed and compared according to pathologies. RESULTS: With regard to quantitative assessments of mural nodules, the number and signal intensity ratios (SIRs) on T1-weighted images were significantly greater in DEs than in SMBTs (11.0 ± 8.4 vs. 4.3 ± 4.1, p < 0.05 and 2.36 ± 0.56 vs. 1.49 ± 0.27, p < 0.01, respectively), whereas the height was significantly lower in DEs than in SMBTs (4.5 ± 1.4 mm vs. 21.9 ± 11.4 mm, p < 0.01). However, there were no significant differences between DEs and SMBTs in the SIRs on T2-weighted images, SIRs on diffusion-weighted images, and apparent diffusion coefficient values. With regard to qualitative assessments of mural nodules, the lobulated margin, pedunculated configuration, and T2 hypointense core were significantly more frequent in SMBTs than in DEs (71% vs. 0%, p < 0.01; 86% vs. 0%, p < 0.01; and 43% vs. 0%, p < 0.05, respectively). CONCLUSION: The number, height, SIRs on T1-weighted images, lobulated margin, pedunculated configuration, and T2 hypointense core of mural nodules within endometriotic cysts were useful MR findings for differentiating DEs from SMBTs.