Aim: This study aimed to investigate temporomandibular joint (TMJ) findings in participants with normal occlusion without any symptoms. Methods: The TMJ was evaluated using magnetic resonance imaging of bilateral TMJs from 20 volunteers with normal occlusion, with no symptoms or history of TMJ disorder or jaw deformity. Regarding the disc morphology, the widths of the anterior band, intermediate zone, and posterior band and the anteroposterior distance were measured. Results: The disc shape was biconcave without disc displacement (DD) in 10 of 40 discs (25.0%). The anteroposterior distance was shorter in the presence of DD. DD was significantly associated with erosion/osteophyte in the condylar head. Conclusion: This study described the morphology and size of the disc in patients with normal occlusion and without TMJ symptoms.

Objective. This study aimed to develop an ultrasound image-based radiomics model for diagnosing cervical lymph node (LN) metastasis in patients with head and neck squamous cell carcinoma (HNSCC) that shows higher accuracy than previous models. Study Design. A total of 537 LN (260 metastatic and 277 nonmetastatic) from 126 patients (78 men, 48 women, average age 63 years) were enrolled. The multivariate analysis software Prediction One (Sony Network Communications Corporation) was used to create the diagnostic models. Furthermore, three machine learning methods were adopted as comparison approaches. Based on a combination of texture analysis results, clinical information, and ultrasound findings interpretated by specialists, a total of 12 models were created, three for each machine learning method, and their diagnostic performance was compared. Results. The three best models had area under the curve of 0.98. Parameters related to ultrasound findings, such as presence of a hilum, echogenicity, and granular parenchymal echoes, showed particularly high contributions. Other significant contributors were those from texture analysis that indicated the minimum pixel value, number of contiguous pixels with the same echogenicity, and uniformity of gray levels. Conclusions. The radiomics model developed was able to accurately diagnose cervical LN metastasis in HNSCC. (Oral Surg Oral Med Oral Pathol Oral Radiol 2025;139:760-769)

Ultrasonography is the preferred modality for detailed evaluation of enlarged lymph nodes (LNs) identified on computed tomography and/or magnetic resonance imaging, owing to its high spatial resolution. However, the diagnostic performance of ultrasonography depends on the examiner's expertise. To support the ultrasonographic diagnosis, we developed YOLOv7-based deep learning models for metastatic LN detection on ultrasonography and compared their detection performance with that of highly experienced radiologists and less experienced residents. We enrolled 462 B- and D-mode ultrasound images of 261 metastatic and 279 non-metastatic histopathologically confirmed LNs from 126 patients with head and neck squamous cell carcinoma. The YOLOv7-based B- and D-mode models were optimized using B- and D-mode training and validation images and their detection performance for metastatic LNs was evaluated using B- and D-mode testing images, respectively. The D-mode model's performance was comparable to that of radiologists and superior to that of residents' reading of D-mode images, whereas the B-mode model's performance was higher than that of residents but lower than that of radiologists on B-mode images. Thus, YOLOv7-based B- and D-mode models can assist less experienced residents in ultrasonographic diagnoses. The D-mode model could raise the diagnostic performance of residents to the same level as experienced radiologists.

This study aimed to retrospectively investigate the prevalence of Sjögren’s syndrome (SS) among patients with ranulas, parotid cysts, or parotid calcifications; identify the characteristic magnetic resonance imaging (MRI) or computed tomography (CT) findings of the lesions associated with SS; and compare the SS disease stages among SS patients with the three lesion types. A total of 228 patients with the lesions were classified into SS, possible SS, and non-SS groups. The prevalence of SS among patients with ranulas, parotid cysts, or parotid calcifications was 16%, 24%, and 40%, and the rates of either SS or possible SS were 25%, 41%, and 64%, respectively. SS was associated with (i) ranulas: ≤17 mm; (ii) parotid cysts: bilateral and multiple; and (iii) parotid calcifications: in females, bilateral, multiple, parenchymal, and no coexisting calcifications in other tissues. SS patients with ranulas were significantly younger and had lower submandibular gland stage scores on MRI/CT than those with other lesions. Additionally, in 58% and 15% of SS patients with ranulas and parotid calcifications, respectively, detection of the lesions led to the diagnosis of primary SS. Therefore, recognizing the prevalence of SS among patients with these lesions and the findings associated with SS can help detect undiagnosed SS.

Objectives This retrospective study compared MRI and US findings among patients with SS over a wide age range. Methods Ninety patients with SS aged 8-84 years who had undergone both MRI and US examinations were divided into four groups according to age, as follows: <18 years (juvenile SS, JSS), 9 patients; 18-39 years, 12 patients; 40-69 years, 53 patients; >69 years, 16 patients. Imaging findings of parotid glands (PGs) and submandibular glands (SMGs) were compared among the four groups. Furthermore, the relationships within and between imaging findings and various clinical findings were examined. Results On MRI, patients with JSS commonly exhibited multiple high-intensity spots in the PGs on MR sialography and fat-suppressed T2-weighted imaging. With increasing SS group age, the frequencies and numbers of the high-intensity spots were lower. Fat areas on MRI and hyperechoic bands on US were rarely observed in the PGs and SMGs of patients with JSS, whereas they were more common in patients with adult SS. In addition, the presence of hyperechoic bands on US, the presence of fat areas on MRI, and decreased salivary flow were associated with one another. Conclusion Salivary gland imaging findings in patients with JSS were characterized by punctate sialectasis, whereas those findings in patients with adult SS were characterized by fatty degeneration. Distinct findings in patients with JSS and adult SS are likely to reflect differences in glandular lesion stage. MRI and US are presumably useful for evaluation of glandular lesion severity during follow-up.

Periosteal fasciitis (PF), a subtype of nodular fasciitis, is an uncommon benign soft-tissue mass that originates from the periosteum or tissues adjacent to bones. PF has rarely seen in children, especially involving in the mandible. This case report presents a rare case of PF originating from the periosteum of the mandible in an 11-year-old girl. She was referred to our hospital with fast-growing painless swelling in her left mandible. Computed tomography revealed an exophytic juxtacortical mass eroding the lower part of the left mandible and lower mandibular cortex with a periosteal reaction. The mass showed low signal intensity on T1-weighted magnetic resonance imaging (MRI) and high signal intensity on T2-weighted MRI. The apparent diffusion coefficient (ADC) of the lesion found to be moderate. Dynamic contrast-enhanced MRI revealed a gradual increment pattern in the central region of the mass. On 18F-fluorodeoxyglucose (FDG) positron-emission tomography/computed tomography (PET/CT), relatively high 18F-FDG uptake was observed on the early scan and the 18F-FDG uptake was declined on the delayed scan. The clinical and conventional radiological findings of the mass were suggestive of malignancy. However, the findings of ADC and dynamic MRI and dual-time-point FDG-PET/CT favored benign etiology over malignant etiology. Histological and immunohistochemical findings along with reactive ossification of the periosteum confirmed the diagnosis of PF. Currently, comprehensive examinations, such as clinical, imaging, and histopathological examinations, are recommended for the definitive diagnosis of PF, while MRI and dual-time-point FDG-PET/CT could have a potential usefulness to differentiate from malignancy.

Juvenile primary Sjögren’s syndrome (pSS) is rare. Although recurrent parotitis is reported to be the most common symptom of juvenile pSS, the clinical symptoms and features of the syndrome are not well understood and are poorly defined. Here we report a rare case of juvenile pSS in a patient with plunging ranula. The patient had no symptoms other than swelling of the oral floor and had no symptoms of parotitis. Magnetic resonance imaging (MRI) revealed the diagnosis of plunging ranula. In addition, the findings of the bilateral parotid glands on MRI and subsequent ultrasonography (US) strongly suggested SS. On the basis of these imaging findings and laboratory data, a pediatric rheumatologist confirmed the diagnosis of juvenile pSS. The ranula may be one clinical sign of SS. However, this association remains generally unknown. Hypothesizing that SS might cause ranula development, we retrospectively investigated cases of patients with ranula who underwent MRI at our hospital. We found that many of these patients (> 20%) had characteristic findings strongly suggestive of SS. This result suggests that SS-induced changes in the sublingual glands are one cause of ranula formation. We think that ranula is a sign of early-stage SS. Therefore, patients with ranulae, whether adults or children, should undergo careful assessment of not only the sublingual glands but also the parotid and submandibular glands with MRI and/or US to investigate possible SS. This assessment may lead to early detection of SS.

A case of tophaceous pseudogout (i.e., calcium pyrophosphate dihydrate crystal deposition disease) in the temporomandibular joint (TMJ) extending into the cranium is reported. A 59-year-old woman was referred to hospital with swelling and pain in the left cheek, and with trismus. Computed tomography imaging revealed a large, granular, calcified mass surrounding the left condylar head, partly destroying the cortex of the condylar head, and extending into the cranium by destroying the glenoid fossa. Magnetic resonance imaging revealed that the soft-tissue mass was of low-signal intensity on T1- and T2-weighted images, and was enhanced after intravenous injection of gadolinium. The mass was clinically and radiographically suspected to be a neoplastic lesion or a synovial osteochodromatosis. However, histological analysis demonstrated that the mass contained granulomatous lesion due to multiple nodular deposits of numerous rod-shaped and rhomboid crystals, which verified the diagnosis of tophaceous pseudogout. The lesion was excised surgically using a preauricular approach. Neither radiographic nor clinical examination demonstrated any signs of mass recurrence in the long-term 8- and 14-year postoperative recall examinations. Tophaceous pseudogout is a rare benign arthropathy that presents with clinical and radiographic features mimicking neoplastic conditions of the TMJ. Therefore, it is recommended that tophaceous pseudogout is considered in the differential diagnosis when a calcified mass lesion of the TMJ is encountered.

We retrospectively evaluated the effectiveness of combined use of salivary gland ultrasonography (US) and the 2016 American College of Rheumatology/European League Against Rheumatic Disease (ACR/EULAR) classification criteria for improving the diagnostic efficiency in patients with Sjögren's syndrome (SS). A US-based salivary gland disease grading system was developed using a cohort comprising 213 SS or non-SS patients who fulfilled the minimum requirements for classifying SS based on the American-European Consensus Group (AECG) and ACR criteria. Using 62 SS or non-SS patients from the 213 patients and who had also undergone all the 5 examinations needed for the ACR/EULAR classification, we compared the diagnostic accuracy of various combinations of the ACR/EULAR and US classifications for diagnosing SS, using the clinical diagnosis of SS by rheumatologists as the gold standard. The ACR/EULAR criteria discriminated clinical SS patients with 77% and 79% accuracy for those with primary or secondary SS and for those with primary SS, respectively. However, the integrated score system of the ACR/EULAR and US classifications yielded 92% and 93% accuracy for these 2 SS patient groups, respectively, provided that US score of 3 was assigned to patients with US grade ≥2, and then patients with integrated threshold score of ≥5 were diagnosed as SS. Cross-validation also indicated improved accuracy of the integrated ACR/EULAR and US score system (91.9 and 93.0% for primary/secondary and primary SS patients, respectively) over that by the ACR/EULAR criteria alone. (74.2 and 86.0%, respectively). The integrated ACR/EULAR and US scoring system can improve the diagnosis of patients with clinical SS.

The perfusion and diffusion properties of a tumor are important clues in evaluating its growth potential and predicting its histological type, such as benign or malignant. Tumor perfusion can be estimated by assessing time-dependent changes in the intratumoral levels of the contrast agent during dynamic contrast-enhanced magnetic resonance (MR) imaging, whereas tumor diffusion can be estimated by assessing intratumoral water diffusivity on diffusion-weighted MR imaging. Granulomatous diseases with different etiologies occur in various head and neck regions, including the mandible, maxillary sinus, salivary glands, and lymph nodes. However, the perfusion and diffusion properties of granulomatous diseases in the head and neck regions are not well documented. In this study, we assessed the time–signal intensity curves and apparent diffusion coefficients of six granulomatous diseases of various histological types that appeared in the soft tissues of the head and neck. Our data show that the perfusion and diffusion characteristics of granulomatous diseases mimic those of malignant diseases, highlighting the need for careful interpretation of MR perfusion and diffusion findings to distinguish between granulomatous diseases and cancers of the head and neck region. Clinicians should pay particular attention to blood examination and biopsy results when interpreting imaging findings.

Tumor perfusion can be evaluated by analyzing the time-signal intensity curve (TIC) after dynamic contrast-enhanced (DCE) MR imaging. Accordingly, TIC profiles are characteristic of some benign and malignant salivary gland tumors. A carcinoma ex pleomorphic adenoma (CXPA) arises from a long-standing pleomorphic adenoma (PA) and has a distinctive prognostic risk depending on the tumor growth potential such as invasion beyond the preexisting capsule. Differentiating CXPA from PA can be very challenging. In this study, we have attempted to discriminate CXPA from PA based on a two-dimensional TIC mapping algorithm. TIC mapping analysis was performed on 8 patients with CXPA and 20 patients with PA after dynamic contrast-enhanced (DCE) MR imaging using a 1.5-T MR system. The TIC profiles obtained were automatically categorized into 5 types based on the enhancement ratio, maximum time, and washout ratio (Type 1 TIC with flat profile, Type 2 TIC with slow uptake, Type 3 TIC with rapid uptake and a low washout ratio, Type 4 TIC with rapid uptake and a high washout ratio, and Type 5 TIC not otherwise specific). The percentage tumor areas with each of the 5 TIC types were compared between CXPAs and PAs. Stepwise differentiation and cluster analysis using multiple TIC cut-off thresholds distinguished CXPAs from PAs with 75% sensitivity, 95% specificity, 86% accuracy, and 86% positive and 90% negative predictive values, when tumors with ≤1.1% Type 1 and ≥15% Type 4, or those with ≤1.1% Type 1, ≥78.1% Type 2, ≥16.1% Type 3, and <15% Type 4, or those with >1.1% Type 1, ≥78.1% Type 2, and ≥16.1% Type 3 areas were diagnosed as CXPAs. The overall TIC profiles predicted some aggressive CXPA growth patterns. These results suggest that stepwise differentiation based on TIC mapping is helpful in differentiating CXPAs from PAs.

Molecular diffusion in a boundary-free medium depends only on the molecular size, the temperature and medium viscosity. However, the critical determinant of the molecular diffusion property in inhomogeneous biological tissues has not been identified. Here, using an in vitro system and a high-resolution MR imaging technique, we show that the length of the intact plasma membrane is a major determinant of water diffusion in a controlled cellular environment and that the cell perimeter length (CPL) is sufficient to estimate the apparent diffusion coefficient (ADC) of water in any cellular environment in our experimental system (ADC = −0.21 × CPL + 1.10). We used this finding to further explain the different diffusion kinetics of cells that are dying via apoptotic or non-apoptotic cell death pathways exhibiting characteristic changes in size, nuclear and cytoplasmic architectures and membrane integrity. These results suggest that the ADC value can be used as a potential biomarker for cell death.

Intravoxel incoherent motion (IVIM) imaging can characterize diffusion and perfusion of normal and diseased tissues, and IVIM parameters are authentically determined by using cumbersome least-squares method. We evaluated a simple technique for the determination of IVIM parameters using geometric analysis of the multiexponential signal decay curve as an alternative to the least-squares method for the diagnosis of head and neck tumors. Pure diffusion coefficients (D), microvascular volume fraction (f), perfusion-related incoherent microcirculation (D*), and perfusion parameter that is heavily weighted towards extravascular space (P) were determined geometrically (Geo D, Geo f, and Geo P) or by least-squares method (Fit D, Fit f, and Fit D*) in normal structures and 105 head and neck tumors. The IVIM parameters were compared for their levels and diagnostic abilities between the 2 techniques. The IVIM parameters were not able to determine in 14 tumors with the least-squares method alone and in 4 tumors with the geometric and least-squares methods. The geometric IVIM values were significantly different (p<0.001) from Fit values (+2 ± 4% and -7 ± 24% for D and f values, respectively). Geo D and Fit D differentiated between lymphomas and SCCs with similar efficacy (78% and 80% accuracy, respectively). Stepwise approaches using combinations of Geo D and Geo P, Geo D and Geo f, or Fit D and Fit D* differentiated between pleomorphic adenomas, Warthin tumors, and malignant salivary gland tumors with the same efficacy (91% accuracy = 21/23). However, a stepwise differentiation using Fit D and Fit f was less effective (83% accuracy = 19/23). Considering cumbersome procedures with the least squares method compared with the geometric method, we concluded that the geometric determination of IVIM parameters can be an alternative to least-squares method in the diagnosis of head and neck tumors.

To evaluate the apparent diffusion coefficient (ADC) for differentiation of cystic lesions of the mandible.

Purpose Cells that are dying via apoptotic or non-apoptotic cell death pathways exhibit characteristic changes in size, nuclear architecture, and membrane integrity [1, 2]. We hypothesised, based on basic diffusion modeling, that these morphological changes affect the diffusion properties of cell cultures. In the course of this study we also established some fundamental relationships between the ADC and cell culture metrics. Methods The ADC values were determined for cell pellets by using 2 b-values (0 and 1000 s/mm) on a 1.5-T MR imaging system (Philips Medical Systems, Best, The Netherlands). Perfusion-related incoherent microcirculation is absent in vitro, thus the ADC can be directly calculated from: ADC = ln(S0/S1000)/1000. The physical properties of cells (HeLa S3, HL-60 and CV-1) that were suspended and centrifugated (200–3200 g) were measured under a microscope (Zeiss, Axioscop) at a magnification of ×40. Results and Discussion We first established that the ADC of HeLa S3 cell pellet is strongly correlated with the cell area (CA; ADC = -1.552 × CA + 1.6864, R = 0.92918) (Fig. 1A). CA includes the nuclear and cytoplasmic area, as measured with AutoMeasure (v4.5, Zeiss). The results are consistent with the notion that increased intracellular water fraction decreases ADC. However, the same expression as for HeLa S3 did not describe correctly the relation between ADC and CA of the other cell lines (Fig. 1A). However, we did find another physical cell parameter that allowed us to calculate the ADC independent of the cell types tested in this study. Indeed, the cell perimeter length (CPL) shows a linear and very strong correlation with the ADC for all cells (ADC = -1.3647 × CPL + 1.1001, R = 0.97827) (Fig. 1B). Thus, the total plasma membrane area, quantified through the CPL, is a very strong determinant of the cell culture’s ADC. Finally, we tested the hypothesis that we could understand the changes in ADC during cell death using these insights. When cells were induced to undergo apoptosis by camptothecin or staurosporine, the ADC of these cell cultures gradually declined (Fig. 2). This finding was consistent with an intact but blebbing plasma membrane and nuclear fragmentation, characteristics of apoptosis. The blebbing of the membrane results in both an increased CPL and an increased CA. In contrast, the ADC values increased in the cells that were induced to non-apoptotic death by tumor necrosis factor α or a caspase inhibitor (Z-VAD-fmk) (Fig. 3). These findings were consistent with a ruptured plasma membrane. A membrane rupture results in decreased CPL. Conclusion These results suggest that the area and integrity of the plasma membranes, as quantified by the total CPL, are critical determinants of the diffusion characteristics on the cellular level. The evolution over time of the ADC values is characteristic of whether the cells die via apoptotic or non-apoptotic (necrotic) pathway. Therefore, this can be used as a cancer biomarker for differentiating between different pathways of cell death, e.g. in testing the effects of cancer drugs in vitro.

Cystic lesions and abscesses of the neck contain fluids that vary in viscosity and content. The purpose of this study was to characterize the fluid areas in cystic and abscess lesions using apparent diffusion coefficients (ADCs).

Objective To compare the diagnostic ability of ultrasonography (US) and MR imaging for discriminating squamous cell carcinoma (SCC) nodes with extranodal spread (ENS) in the neck. Methods US and MR imaging was retrospectively evaluated for differentiating ENS-positive (n=28) from ENS-negative (n=26) SCC nodes (>10mm short-axis diameter) in 50 patients with head and neck SCCs. We assessed nodal size on US and MR images; irregular nodal margin on US; and vanishing nodal border, flare, and shaggy nodal margin signs on T1-, fat-suppressed T2-, and contrast-enhanced T1-weighted MR images, respectively. US and MR images were analyzed by 3 radiologists in consensus and the results were compared between ENS-positive and ENS-negative SCC nodes. Results The nodal sizes of ENS-positive nodes (21±9mm) were significantly larger than those of ENS-negative SCC nodes (14±4mm) (p<0.001). Irregular nodal margins were more frequently observed in ENS-positive SCC nodes (75%) than in ENS-negative SCC nodes (12%). The vanishing nodal margin, flare, and shaggy nodal margin signs were more frequently observed in ENS-positive SCC nodes (93%, 89%, and 82%, respectively) than in ENS-negative nodes (46%, 19%, and 19%, respectively). A combination of size (≥22mm) and imaging criteria (irregular margin or flare sign) best discriminated ENS-positive SCC nodes with 82% sensitivity, 89% specificity, and 85% accuracy for US and 89% sensitivity, 81% specificity, and 85% accuracy for MR imaging. Conclusion US discriminated ENS-positive from ENS-negative SCC nodes with comparable accuracy and higher specificity than MR imaging.

Differentiation between juvenile recurrent parotitis and juvenile Sjögren’s syndrome may be difficult on the basis of clinical symptoms and imaging examinations, such as sialography and ultrasonography. Histological findings of the labial glands may also not be definitive for this purpose. Here, we report three cases of patients with juvenile recurrent parotitis who underwent magnetic resonance imaging examinations. The imaging results suggest that magnetic resonance imaging may be an effective tool for differentiating between these two distinct salivary gland diseases.

PURPOSE:To evaluate the stepwise approach in differentiating between benign and malignant salivary gland tumors using time-intensity curves (TICs) and apparent diffusion coefficients (ADCs). MATERIALS AND METHODS:TICs and ADCs were analyzed on the tumor-by-tumor (overall) and pixel-by-pixel (TIC and ADC maps) bases in patients with benign (n = 52) or malignant (n = 18) salivary gland tumor. TICs were categorized into Types 1 (<20% increment ratio), 2 (>or=20% increment ratio and >120 sec peak time), 3 (>or=20% increment ratio, or=20% increment ratio, or=30% washout ratio). ADCs were classified as extremely low (<0.6 x 10(-3) mm(2)/sec), low (<1.2), intermediate (<1.8), or high (>or=1.8). RESULTS:Malignant tumors had small (<30%) areas with Type 1 TIC with one of the following magnetic resonance imaging (MRI) characteristics: Type 3 overall TIC patterns, Type 4 overall TIC patterns and extremely low (<0.60 x 10(-3) mm(2)/sec) overall ADCs, or Type 2 overall TIC patterns and large (>40%) areas with low or extremely low ADCs. CONCLUSION:We propose a stepwise approach by using multiparametric MRI techniques as an effective tool for differentiating between benign and malignant salivary gland tumors.