Differentiation of radicular cysts and radicular granulomas via texture analysis of multi-slice computed tomography images.

OBJECTIVES: This study aimed to establish a method for differentiating radicular cysts from granulomas via texture analysis (TA) of multi-slice computed tomography (CT) images. METHODS: A total of 222 lesions with multi-slice computed tomography images acquired at our hospital between 2013 and 2022 that were pathologically diagnosed were included in this study. Cases of contrast-enhanced images, severe metallic artefacts, and lesions that were not sufficiently large to be analysed were excluded. The images were chronologically divided into a training group and a validation group. The radiological characteristics were determined. Subsequently, a TA was performed. Pyradiomics software was used for the TA of three-dimensionally segmented volumes extracted from 2 mm slice thickness images with a soft-tissue algorithm. Features that differed significantly between the two lesions in the training group were extracted and used to create machine-learning models. The discriminative ability of these models was evaluated in the validation group using receiver operating characteristic curve analysis. RESULTS: A total of 131 lesions, comprising 28 radicular cysts and 103 granulomas, were analysed. Forty-three texture features that exhibited significant variations were extracted. A support vector machine and decision tree model, with areas under the curves of 0.829 and 0.803, respectively, were created. These models showed high discriminative abilities, even for the validation group, with areas under the curve of 0.727 and 0.701, respectively. Both models showed superior performance compared with that of the models based on radiographic findings. CONCLUSION: Discriminatory models were established for the TA of radicular cysts and granulomas using CT images.

Dental implant in anterior mandible according to mandibular lingual foramens and lingual mucosal vessels: using fusion volumetric images from computed tomography and magnetic resonance imaging.

BACKGROUND: Perforation of the lingual cortex while placing dental implants in the interforaminal region of the mandible can cause severe hemorrhage. The purpose of this study was to evaluate the features of mandibular lingual foraminals (MLFs) and locational relationship between them and lingual mucosal vessels (LMVs) by CT/MRI fusion volumetric images. METHODS: 37 images within complete anterior mandibular region using both MSCT and three-dimensional volumetric interpolated breath-hold examination (3D-VIBE) MRI were taken from our imaging archives. After exclusion of 11 for lesions or artifacts, 26 CT/MRI fusion volumetric images were included to evaluate the frequency, diameter, and position of MLFs. The anterior mandibular region was divided into 4 equal segments under each teeth, and 40 regions were got from C5 to D5. Furthermore, the positional relationship between MLFs and LMVs was analyzed in this coordinate system. RESULTS: 62 MLFs (73.81%) were located below the incisors, followed by premolars (21.43%) and canines (4.76%). Female bias, the mean diameter of the female was 0.08 mm while the male was 0.21 mm. The total number of LMVs was most distributed on lingual side of C1 and D1. According to Spearman's correlation coefficient, the location of MLFs was related to LMVs. The MLFs in fourth segment of D1 were positively moderately correlated with LMVs in fourth segment of D4, while the MLFs in third segment of C1 showed a weak positive correlation with LMVs in third segment of D4. CONCLUSIONS: The features and the correlation between MLFs and LMVs in CT/MRI fusion volumetric images may offer reference to dentists when only MLFs can been seen on routine preoperative CT examination of implants. TRIAL REGISTRATION: Retrospectively registered. (D2018-072).

Clinical manifestations of diffuse large B-cell lymphoma that exhibits initial symptoms in the maxilla and mandible: a single-center retrospective study.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphatic tumor; however, extranodal DLBCLs that exhibit initial symptoms in the maxilla and mandible are rare. Moreover, DLBCL is clinically classified as a moderate to highly malignant lymphatic tumor that can progress rapidly; therefore, early diagnosis is crucial. However, diagnosis is difficult as the disease causes a diverse range of clinical symptoms with no characteristic imaging findings. We conducted a clinical investigation to clarify the clinical characteristics of DLBCL that exhibits initial manifestation in the maxilla and mandible. METHODS: Of the 2748 patients with malignant tumors of the oral and maxillofacial region examined at our hospital during a period of 11 years between January 2006 and December 2016, 27 primary cases diagnosed with DLBCL based on the chief complaint of symptoms in the gingiva and bone of the maxilla and mandible were enrolled in this study. Evaluations were based on sex, age, whether treatment was provided by a previous physician, symptoms, duration of disease until treatment was sought, clinical diagnosis, laboratory findings, and imaging results. RESULTS: There were 15 cases that involved the maxilla and 12 that involved the mandible. The median duration of disease until treatment was sought was 60 d (3-450 d). All cases exhibited a tumor or a mass, and hypoesthesia of the chin was confirmed in eight cases wherein the mandible was involved. The clinical stages were stage I in eight cases, stage II in ten cases, and stage IV in nine cases. Serum lactate dehydrogenase (LDH) levels were elevated in 13 of 22 patients. The overall survival rate was 63%. CONCLUSIONS: Symptoms associated with nontender swelling and numbness of the lip or chin in the absence of other findings such as dental infections should raise suspicions about DLBCL. Patients should be provided appropriate imaging and accurate biopsy assessments to improve prognosis.

Uterine Cervical Carcinoma: Evaluation Using Non-Gaussian Diffusion Kurtosis Imaging and Its Correlation With Histopathological Findings.

OBJECTIVE: The aim of the study was to assess non-Gaussian diffusion kurtosis imaging (DKI)'s usefulness as a noninvasive method to evaluate tumor invasion depth, histological grade, and lymph node metastasis in cervical carcinoma (CC) patients. METHODS: Twenty-two consecutive patients with histologically confirmed CC were examined by 1.5-T MRI and non-Gaussian DKI with 4 b values of 0, 500, 1000, and 2000 s/mm2. Kurtosis (K), diffusivity (D), and apparent diffusion coefficient (ADC) maps were compared with histopathological findings. RESULTS: Kurtosis maps revealed the fibrous stroma as a distinct high K zone (1.442 ± 0.373) that was significantly different from values of the cervical mucosa, outer stroma, and parametrium (0.648 ± 0.083, 0.715 ± 0.113, and 0.504 ± 0.060, respectively, P < 0.0001). Kurtosis (1.189 ± 0.228) and D (0.961 ± 0.198 × 10-3 mm2/s) values of all CCs were significantly different from those of all uterine cervical wall layers. Kurtosis and D values were significantly correlated with histological grades of CCs (r = 0.934, P < 0.0001, and r = -0.925, P < 0.0001, respectively), whereas no significant differences were found in ADC values between grades 2 and 3 CCs (P = 0.787). Metastatic and nonmetastatic lymph nodes showed significantly different K (P < 0.0001) and D (P < 0.0001) values; however, their ADC values did not show significant differences (P = 0.437). For differentiating grade 3 CCs from grade 1 or 2 CCs, the areas under the curve for K (0.991, P = 0.0375) and D (0.982, P = 0.0337) values were significantly higher than those for ADC values (0.759). For differentiating metastatic and nonmetastatic lymph nodes, the areas under the curve for K (0.974, P = 0.0028) and D (0.968, P = 0.0018) values were significantly higher than those for ADC (0.596). CONCLUSIONS: Non-Gaussian DKI may be clinically useful for noninvasive evaluation of tumor invasion depth, histological grade, and lymph node metastasis in CC patients.

Usefulness of MR imaging for odontogenic tumors.

MRI has become an invaluable diagnostic tool in all areas of the body. However, it has not been widely used to image odontogenic tumors of the jaw. Major advantages of MRI include excellent soft tissue contrast in the absence of ionizing radiation. Furthermore, diffusion-weighted MRI and dynamic contrast-enhanced MRI can be used as functional imaging techniques for assessing tissue biology. In this review article, we present representative MR images of several types of odontogenic tumors, and discuss MR imaging characteristics useful for differential diagnosis.

Differences in the Clinical Characteristics of Persistent Idiopathic Facial Pain (Atypical Odontalgia) Patients with or Without Neurovascular Compression of the Trigeminal Nerve.

BACKGROUND: Persistent idiopathic facial pain (PIFP) is the unexplained pain along the territory of the trigeminal nerve, including nonorganic tooth pain called atypical odontalgia (AO). Though PIFP is debilitating to patients' livelihood and well-being, its pathophysiology remains poorly understood. Although neurovascular compression (NVC) of the trigeminal nerve is known to be associated with trigeminal neuralgia (TN), the relationship between NVC and other orofacial pains has not been fully elucidated. METHODS: In this study, we investigated the differences in the characteristics of PIFP (primarily AO) patients in the presence or absence of NVC. A retrospective analysis was performed on data from 121 consecutive patients who had been diagnosed with unilateral PIFP according to the criteria of the International Classification of Headache Disorders (ICHD)-3 and underwent magnetic resonance imaging scans of the head. RESULTS: In the group without NVC, characteristic findings were significant for psychiatric morbidity, somatization, and pain disability, when compared with the group with NVC. Furthermore, the group without NVC exhibited significant headache, noncardiac chest pain, shortness of breath, and pain catastrophizing. CONCLUSIONS: These results suggest that PIFP patients can be divided into two groups: one consistent with a neuropathic pain phenotype when NVC is present and a functional somatic symptom phenotype when presenting without NVC. Our findings may enable a more precise understanding of pathophysiology of PIFP and lead to better treatment strategies.

Colorectal carcinoma: Ex vivo evaluation using q-space imaging; Correlation with histopathologic findings.

BACKGROUND: Although the prognosis of colorectal carcinoma (CRC) patients depends on the histologic grade (HG) and lymph node metastasis (LNM), accurate preoperative assessment of these prognostic factors is often difficult. PURPOSE: To assess the HG and extent of LNM by q-space imaging (QSI) for preoperative diagnosis of CRC. STUDY TYPE: Prospective. SPECIMEN: A total of 20 colorectal tissue samples containing adenocarcinomas and resected lymph nodes (LNs). FIELD STRENGTH/SEQUENCE: QSI was performed with a 3T MRI system using a diffusion-weighted echo-planar imaging sequence: repetition time, 10,000 msec; echo time, 216 or 210 msec; field of view, 113 × 73.45 mm; matrix, 120 × 78; section thickness, 4 mm; and 11 b values ranging from 0 to 9000 s/mm2 . ASSESSMENT: The mean displacement (MDP; µm), zero-displacement probability (ZDP; arbitrary unit [a.u.]), kurtosis (K; a.u.), and apparent diffusion coefficient (ADC) were analyzed by two observers and compared with histopathologic findings. STATISTICAL TESTS: Spearman's rank correlation coefficient, Mann-Whitney U-test, and ROC curve analyses. RESULTS: For all 20 carcinomas, the MDP, ZDP, K, and ADC were 8.87 ± 0.37 µm, 82.0 ± 6.2 a.u., 74.3 ± 3.0 a.u., and 0.219 ± 0.040 × 10-3 mm2 /s, respectively. The MDP (r = -0.768; P < 0.001), ZDP (r = 0.768; P < 0.001), and K (r = 0.785; P < 0.001) were significantly correlated with the HG of CRC, but not the ADC (r = 0.088; P = 0.712). There were also significant differences in the MDP, ZDP, and K between metastatic and nonmetastatic LNs (all, P < 0.001), but not the ADC (P = 0.082). In the HG of CRC and LNM, the area under the curve was significantly greater for MDP, ZDP, and K than for ADC. DATA CONCLUSION: QSI provides useful diagnostic information to assess the HG and extent of LNM in CRC. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1059-1068.

Atypical MRI and Histopathological Findings in Dermoid Cyst.

On images, a dermoid cyst is often described as resembling a "sack of marbles" or "marbles in a bag". Typically, it comprises an inhomogeneity filled with multiple nodules in a fluid matrix on both computed tomography and magnetic resonance imaging (MRI). How it appears, however, will vary depending on its histological contents, which may cause confusion in arriving at a diagnosis. This report describes a dermoid cyst in the floor of the mouth of a 55 year-old woman that showed an atypical internal appearance on MRI. Most of the lesion showed homogeneous high signal intensity on T1 - and T2-weighted images, suggesting that it was derived from fat. A small area within the mass, however, showed moderate signal intensity almost equal to that of muscle on T1-weighted images and high signal intensity on fat-suppressed T2-weighted images. Given the location of the lesion, a dermoid cyst was one possible diagnosis. A lipoma or lipoma variants were also considered, however, based on signal intensity. Histopathological section of the excised specimen revealed a dermoid cyst with sebaceous glands in its walls and keratin in its cavity. Dermoid cysts show variation in their internal structures and contents. Since MRI can reflect such histological variation, signal intensity requires careful interpretation.

Application of diffusion kurtosis imaging to odontogenic lesions: Analysis of the cystic component.

PURPOSE: To assess the feasibility of applying diffusion kurtosis imaging (DKI) to common odontogenic lesions and to compare its diagnostic ability versus that of the apparent diffusion coefficient (ADC) for differentiating keratocystic odontogenic tumors (KCOTs) from odontogenic cysts. MATERIALS AND METHODS: Altogether, 35 odontogenic lesions were studied: 24 odontogenic cysts, six KCOTs, and five ameloblastomas. The diffusion coefficient (D) and excessive kurtosis (K) were obtained from diffusion-weighted images at b-values of 0, 500, 1000, and 1500 s/mm2 on 3T magnetic resonance imaging (MRI). The combination of D and K values showing the maximum density of the probable density function was estimated. The ADC was obtained (0 and 1000 s/mm2 ). Values for odontogenic cysts, KCOTs, and ameloblastomas were compared. Multivariate logistic regression modeling was performed to assess the combination of D and K model versus ADC for differentiating KCOTs from odontogenic cysts. RESULTS: The mean D and ADC were significantly higher for ameloblastomas than for odontogenic cysts or KCOTs (P < 0.05). The mean K was significantly lower for ameloblastomas than for odontogenic cysts or KCOTs (P < 0.05). The mean values of all parameters for odontogenic cysts and KCOTs showed no significant differences (P = 0.369 for ADC, 0.133 for D, and 0.874 for K). The accuracy of the combination of D and K model (76.7%) was superior to that of ADC (66.7%). CONCLUSION: Use of DKI may be feasible for common odontogenic lesions. A combination of DKI parameters can be expected to increase the accuracy of its diagnostic ability compared with ADC. J. Magn. Reson. Imaging 2016;44:1565-1571.

The magnetic resonance imaging characteristics of radicular cysts and granulomas.

OBJECTIVES: Limited studies have differentiated radicular cysts and granulomas with MRI. Therefore, we investigated the MRI characteristics of the two lesions and clarified features for distinguishing between them. METHODS: We collected data of 27 radicular cysts and 9 granulomas definitively diagnosed by histopathology and reviewed the fat-saturated T2 weighted, T1 weighted, and contrast-enhanced fat-saturated T1 weighted images. We measured the maximum diameter and apparent diffusion coefficient values of the lesions. We employed Fisher's exact test, the Mann-Whitney U test, and independent t-tests to compare the two lesions and created a decision tree for discriminating between them. RESULTS: There were significant differences between radicular cysts and granulomas with respect to five imaging characteristics-signal intensity of the lesion centre on fat-saturated T2 weighted images; signal intensity, texture, and contrast enhancement of the lesion centre on contrast-enhanced fat-saturated T1 weighted images; and maximum diameter of the lesion. The cut-off diameter for radicular cysts was 15.9 mm. The area under the receiver operating characteristic curve, sensitivity, and specificity were 0.971, 85.2%, and 100%, respectively. CONCLUSIONS: From the decision tree analysis, maximum diameter, lesion centre contrast enhancement on contrast-enhanced fat-saturated T1 weighted images, and lesion centre signal intensity on fat-saturated T2 weighted images were important for discriminating between radicular cysts and granulomas.

Magnetic resonance imaging of methotrexate-related lymphoproliferative disorder with a chief complaint of oral symptoms.

OBJECTIVES: To determine the magnetic resonance imaging (MRI) features of methotrexate-related lymphoproliferative disorder (MTX-LPD) in the oral cavity of a patient with a chief complaint of oral symptoms. METHODS: We included six patients who visited our hospital between November 2014 and November 2019, histopathologically diagnosed with MTX-LPD. All images were examined using 3 T MRI and reviewed by two radiologists. RESULTS: Masses were detected in five cases; all masses demonstrated signal hypointensity and homogeneous signal hyperintensity on T1- and T2-weighted images with fat suppression. Homogeneous enhancement with fat suppression was evident on post-contrast T1-weighted imaging. We performed dynamic contrast-enhanced MRI in three cases and observed early enhancement with a low washout ratio pattern in all cases. Four patients underwent diffusion-weighted MRI and revealed low mean apparent diffusion coefficient (ADC) of 0.57 (range 0.5-0.65) × 10-3 mm2/s. CONCLUSIONS: We reported on the imaging characteristics of six rare cases of MTX-LPD in the oral cavity. Homogeneous hyperintensity on fat-suppressed T2-weighted images and low ADC values are possible features of MTX-LPD. Moreover, MTX-LPD can be differentiated from other carcinomas in the oral cavity.

Invasion of the bucco-mandibular space by oral squamous cell carcinoma: histopathological analysis of invasion pattern.

Background: This study aimed to determine the patterns of invasion of oral squamous cell carcinoma (OSCC) into the bucco-mandibular space (BMS) using detailed histopathological analysis and to assess clinical outcomes. Methods: Patients with OSCC who underwent segmental mandibulectomy or hemi-mandibulectomy combined with resection of the BMS between 2012 and 2021 were included. The invasions of the BMS were classified into three patterns. Pattern A was defined as a horizontal invasion, Pattern B as a vertical invasion, and Pattern C as an expansive invasion. Results: In total, 109 patients were reviewed. Of these 109 patients, the primary tumor affected the lower gingiva in 78 patients, the buccal mucosa in 18 patients, and was a primary intraosseous carcinoma of the mandible in 13 patients. Invasion of the BMS was significantly associated with a higher pathological T stage, positive/close margins, and lower disease-free survival (DFS) rates. The DFS rates were 86.7% and 66.0% in the BMS non-invasion and invasion groups, respectively. The DFS rates for each type of invasion were 82.1% for Pattern A, 67.4% for Pattern B, and 48.0% for Pattern C (P=0.277). Conclusion: Patients with BMS invasion have a poorer prognosis than those without invasion of the BMS. Therefore, adjuvant therapy is necessary, especially in Patterns B and C. Evaluation of preoperative BMS invasion patterns is important for predicting the prognosis of OSCC.

Differentiation of cystic lesions in the jaw by conventional magnetic resonance imaging and diffusion-weighted imaging.

OBJECTIVES: This study aimed to determine the discrimination power of apparent diffusion coefficient (ADC) for cystic lesions in the jaw using MRI. METHODS: We selected 127 cystic lesions, comprising dentigerous cysts (DCs), odontogenic keratocysts (OKCs), and unicystic ameloblastomas (UABs), from our MRI database examined by 3T MRI, including diffusion-weighted imaging sequences, and we reviewed their imaging characteristics. We attempted to discriminate the three types of lesions by ADC values with receiver operator characteristic analysis; however, satisfactory results were not obtained for differentiation between DC and OKC. Therefore, we performed a decision tree analysis. RESULTS: The imaging characteristics of the lesions were significantly different according to Fisher's exact test, except for differences in sex. The ADC values statistically discriminated the lesions of DC and UAB, OKC and UAB, but not DC and OKC. Thus, differentiation was performed by a decision tree for DC and OKC by evaluating the following points: the attached tooth condition, signal intensity on the T1 weighted image (T1SI), ADC value, and the cyst site. However, cases showing hypo- or isointense T1SI with an ADC value under 1.168 × 10-3 mm2/s were difficult to differentiate. CONCLUSION: The ADC value helped distinguish UAB from both DC and OKC, but not DC from OKC. However, the decision tree based on ADC value, tooth contact status, and T1SI helped differentiate DC and OKC to some extent.

Retrospective analysis of schwannoma in the oral and maxillofacial region: clinicopathological characteristics and specific pathology of ancient change.

Schwannomas are benign tumours that originate from the Schwann cells of the nerve. Despite the frequency of their occurrence in the head and neck, data relating to their clinicopathological features in the region are limited. This study reviews the clinicopathological characteristics and specific pathology of ancient (degenerative) change in 40 cases in the oral and maxillofacial region. Medical records were reviewed of the 40 cases treated at Tokyo Medical and Dental University Hospital Faculty of Dentistry between 2000 and 2020. The most frequently involved site was the tongue, and the average tumour size was 13.2 mm. Degenerative changes were observed in eight cases. All tumours were completely excised through biopsy or local excision, and no recurrence was observed on clinical follow up. Statistical analyses revealed significant associations (p < 0.05) between ancient change and tumour size, and between ancient change and the apparent diffusion coefficient (ADC) value derived from diffusion-weighted magnetic resonance imaging (MRI). Analysis suggests that schwannoma progresses over a long period and subsequently undergoes secondary ancient changes. Pathological events such as cystic formation and haemorrhage that are associated with ancient changes, cause hypocellularity and lead to high ADC values. These values may indicate ancient change and should be considered when distinguishing schwannoma from other lesions.

Osteosarcoma of maxilla with unusual image findings in child.

Osteosarcoma of the head and neck is relatively rare and accounts for less than 10 percent of all osteosarcomas in general. We report a case of osteosarcoma in which imaging and histopathology of the hard palate of an 11-year-old boy yielded atypical findings. An approximately 8×15mm lesion found in the center of the palate was hard and healthy in color. Subsequent biopsy resulted in a diagnosis of nonepithelial malignant tumor. No abnormalities were observed in the maxillary bone or tooth on panoramic or occlusal radiographs. Computed tomography images revealed a mass lesion approximately 7×9×9mm in size on the hard palate extending into the maxilla. The cortex of the maxilla adjacent to the lesion was unclear in parts. The internal structures were slightly inhomogeneous and its density was lower than that of muscle. On magnetic resonance images, the lesion was represented by low signal intensity on T1-weighted (T1W) images and high signal intensity on T2-weighted images with fat-suppression. The margin of the lesion was a little unclear and the internal structures were slightly inhomogeneous. The lesion was enhanced homogeneously on post-contrast T1W images with fat-suppression. The histopathological diagnosis was fibrogenesis-type osteosarcoma. No findings specific to osteosarcoma such as localized enlargement of the periodontal ligament space alongside the root, cortical destruction, periosteal ossification or osteogenesis were found in this case.

Reliance on diagnostic elements in panoramic imaging with focus on ameloblastoma and keratocystic odontogenic tumor: psychometric study.

The purpose of this study was to investigate degree of observer reliance (RD) on specific diagnostic elements in differential diagnosis of ameloblastoma (AB) and keratocystic odontogenic tumors (KOT) on panoramic images. The RD for 12 diagnostic elements, including 2 clinical and 10 radiographic elements, as recorded by eight dental radiologists on an ordinal ranking scale, was determined for 9 ABs and 9 KOTs. Intraobserver (IaOC) and inter-observer concordance (IeOC) for both ABs and KOTs were statistically analyzed in terms of RD. Significant differences in IeOC were also investigated between ABs and KOTs. The ranking of diagnostic elements was identified in each case of AB or KOT and classified according to IeOC. The mean rating scores of the 10 radiographic elements were then statistically compared and the RD for radiographic elements classified in each group. Good IaOC and IeOC were identified for the RD for the 12 diagnostic elements. IeOC differed significantly between the AB and KOT groups: the AB group showed higher concordance than the KOT group. Ameloblastoma lesion groups where IeOC was relatively high (χ(2)≥70, 70>χ(2)≥60) enabled ranking into four groups. Keratocystic odontogenic tumor lesion groups with χ(2) values of ≥50 and <50 showed ranking into five groups and two groups, respectively. In particular, the AB lesion groups showed a highly significant difference for the specified element of "adjacent radicular state". In panoramic diagnosis, the RD of dental radiologists for diagnostic elements is more consistent for AB than for KOT. In particular, "radicular state adjacent to a lesion" may be an decisive element in distinguishing between AB and KOT.

Applying the paralleling technique in intraoral periapical radiographs for Japanese patients by analyzing CT images.

OBJECTIVES: The aim of this study was to investigate the size of the teeth and palatal heights to determine if it is possible to apply the paralleling technique in the upper molar region in Japanese patients. METHODS: The medical computed tomography (CT) data of ten patients were analyzed. A minimum intensity projection image with 8-mm slice thickness was created for each second premolar, first molar, and second molar tooth. We traced the tooth, the alveolar bone, the plate bone surface, and the cheek skin surface on a tracing paper. Tooth length (TL), palatal height (PH), distance between a tip of the cheek and each tooth (D1), and distance between each tooth and the receptor (D2) were measured. The measurements were performed by two observers, and the measurements were repeated twice by each observer. Two potential situations were considered for application of the paralleling technique. RESULTS: We analyzed whether there was a possibility for application of the paralleling technique comparing the TL and the PH for each case by considering the magnification rate calculated from D1 and D2, the palatal mucosa thickness, and the safety margin within the resultant image. The data suggested that applying the paralleling technique was impossible in 95% of cases. In the cases where application of the paralleling technique was impossible, the incident angle of X-ray increased by 31.6°. CONCLUSIONS: We concluded that the paralleling technique could not be applied in Japanese patients due to insufficient space for the image receptor in the upper maxilla region.

A case of vestibular schwannoma with oral burning sensation: surgical complication or burning mouth syndrome?

BACKGROUND: Despite improvements in surgical techniques, the removal of vestibular schwannoma is related to some complications. Recovery from surgical complications of vestibular schwannoma is often difficult and complications sometimes lead to permanent deficits. However, treatable trigeminal symptoms may be missed in atypical cases. CASE PRESENTATION: A 46-year-old woman complained about burning sensation on her tongue and maxilla for four years before her first visit to our clinic. She visited the neurosurgery department in a university hospital because her facial pain and burning sensation of her tongue were suddenly aggravated. She was diagnosed with vestibular schwannoma and tumour resection was performed. However, her oral pain persisted after surgery. Two months before the initial visit to our clinic, the oral pain became more severe than ever before. When the patient visited a psychiatrist due to a panic attack, the psychiatrist diagnosed her as having somatic symptom disorder and depression and referred her to our clinic. Based on the characteristics of the pain, she was diagnosed as burning mouth syndrome and treated for the same. Within 1.5 months, the pain and burning sensation of the tongue and maxilla almost completely remitted with low dose amitriptyline. CONCLUSIONS: Our case suggests that there are exceptional cases in which burning mouth syndrome and vestibular schwannoma occur simultaneously. Burning pain after vestibular schwannoma surgery cannot always be considered a complication of surgery.

Effective combination of 3 imaging modalities in differentiating between malignant and benign palatal lesions.

OBJECTIVE: The aim of this study was to evaluate whether computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT) can effectively differentiate between malignant and benign palatal lesions. STUDY DESIGN: In total, 59 patients with palatal lesions (32 malignant and 27 benign), who underwent CT, MRI, and/or PET/CT imaging examinations and had histopathological diagnoses, were divided into an analysis group (n = 46) and a validation group (n = 13). Bone changes adjacent to the lesion, MRI signal intensity, apparent diffusion coefficient (ADC), time to peak enhancement (Tpeak), and maximum standardized uptake values (SUVmax) were evaluated in the analysis group. Diagnostic performance was individually assessed for each parameter for differentiating between malignant and benign lesions. A diagnostic decision tree was constructed by using useful parameters and its accuracy tested in the validation group. RESULTS: The frequency distribution of bone change types and Tpeak differed significantly between malignant and benign lesions. The ADC of malignant lymphoma was significantly lower than that of other lesions. The other parameters did not distinguish between lesion types. The accuracy of the decision tree, constructed by using bone change types, ADC, and Tpeak, was 87.5%. CONCLUSIONS: Bone change types, ADC values, and Tpeak are useful for differentiating between malignant and benign palatal lesions.

MRI before biopsy correlates with depth of invasion corrected for shrinkage rate of the histopathological specimen in tongue carcinoma.

The purpose of this study was to evaluate which radiological depth of invasion (r-DOI) measurement is the most concordant to clinical DOI (c-DOI) derived from correction for the shrinkage rate of the histopathological specimens. We retrospectively reviewed 128 patients with tongue carcinoma who had undergone glossectomy between 2006 and 2019. At first, the width shrinkage rate during formalin fixation and preparation process of histopathological specimens was evaluated. From the shrinking rates, a formula to calculate c-DOI from pathological DOI (p-DOI) was developed. The correlation between c-DOI and r-DOI was evaluated. The specimen shrinkage rate during the histopathological specimen preparation process was 10.3%. Based on that, we yielded the correct formula for c-DOI based on p-DOI and preparation shrinkage rate: c-DOI = p-DOI × 100/89.7. The regression equations for the association of c-DOI with r-DOI measured by ultrasound (n = 128), MRI before biopsy (n = 18), and MRI after biopsy (n = 110) were y = 1.12 * x + 0.21, y = 0.89 * x - 0.26, and y = 0.52 * x + 2.63, respectively, while the coefficients of determination were 0.664, 0.891, and 0.422, respectively. In conclusion, r-DOI using MRI before biopsy most strongly correlated with c-DOI.