Tetsuji Nagata

Clinical Significance of Combined Assessment of the Maximum Standardized Uptake Value of F-18 FDG PET with Nodal Size in the Diagnosis of Cervical Lymph Node Metastasis of Oral Squamous Cell Carcinoma

RATIONALE AND OBJECTIVES This study aimed to elucidate the diagnostic accuracy of F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) for nodal involvement in oral squamous cell carcinoma (OSCC), and to reveal clinically useful factors to distinguish between true-positive (TP) and false-positive (FP) nodes. MATERIALS AND METHODS Thirty-eight patients with primary OSCC who underwent neck dissection were assessed. The diagnostic accuracy of F-18 FDG PET/CT was evaluated, and then compared with that of CT/ultrasonography (US). Furthermore, the association of the maximum standardized uptake value (SUVmax) and nodal size with the histopathologic findings was examined. RESULTS Sensitivity and specificity using F-18 FDG PET/CT were 77.1% and 97.3%, and those using CT/US were 72.9% and 98.9%, respectively. The SUVmax of TP nodes was significantly higher than that of FP nodes. Nodes with SUVmax >4.5 were pathologically confirmed as metastasis. Nodes with SUVmax ≤4.5 were further discriminated between TP and FP nodes by using the long axis diameters or the ratios of long to short axis diameter as clinical parameters. Positive correlation between the SUVmax and the short-axis diameter was found in TP nodes. The AUC obtained from the ROC curves of the SUVmax alone (AUC, 0.804) was improved by combination with the long-axis diameter (AUC, 0.867) or the short-axis diameter (AUC, 0.846), although no significant difference was found. CONCLUSIONS These results indicated that F-18 FDG PET/CT was potentially useful in diagnosing preoperative nodal state. Furthermore, combined assessment of SUVmax with nodal size could be significant in the identification of metastatic lymph nodes in OSCC patients.

Imaging mass spectrometry distinguished the cancer and stromal regions of oral squamous cell carcinoma by visualizing phosphatidylcholine (16:0/16:1) and phosphatidylcholine (18:1/20:4)

Most oral cancers are oral squamous cell carcinoma (OSCC). The anatomical features of OSCC have been histochemically evaluated with hematoxylin and eosin. However, the border between the cancer and stromal regions is unclear and large portions of the cancer and stromal regions are resected in surgery. To reduce the resected area and maintain oral function, a new method of diagnosis is needed. In this study, we tried to clearly distinguish the border on the basis of biomolecule distributions visualized by imaging mass spectrometry (IMS). In the IMS dataset, eleven signals were significantly different in intensity (p < 0.01) between the cancer and stromal regions. Two signals at m/z 770.5 and m/z 846.6 were distributed in each region, and a clear border was revealed. Tandem mass spectrometric (MS/MS) analysis identified these signals as phosphatidylcholine (PC) (16:0/16:1) at m/z 770.5 in the cancer region and PC (18:1/20:4) at m/z 846.6 in the stromal region. Moreover, the distribution of PC species containing arachidonic acid in the stromal region suggests that lymphocytes accumulated in response to the inflammation caused by cancer invasion. In conclusion, the cancer and stromal regions of OSCCs were clearly distinguished by use of these PC species and IMS analysis, and this molecular identification can provide important information to elucidate the mechanism of cancer invasion.

Comparison of Fuzzy Inference, Logistic Regression, and Classification Trees (CART) Prediction of Cervical Lymph Node Metastasis in Carcinoma of the Tongue

OBJECTIVES In this paper three statistical methods [logistic regression, classification and regression tree (CART), and fuzzy inference] for the prediction of lymph node metastasis in carcinoma of the tongue are compared. METHODS A retrospective collection of data in 75 patients treated for tongue cancer was carried out at the Clinic and Policlinic for Oral and Maxillo-facial Surgery at the University Hospital of Freiburg in Germany between January 1990 and December 1999; biopsy material was used for laboratory evaluations. Statistical methods for the prediction of lymph node metastasis were compared using ROC curves and accuracy rates. RESULTS All three methods show similar results for the prediction of lymph node metastasis with slightly superior results for fuzzy inference and CART. A great overlap is apparent in the ROC curves. The best result observed for fuzzy inference and CART was a sensitivity of 79.2% [95% confidence interval: (57.8%; 92.9%)] and a specificity of 86.3% (73.7%; 94.3%); the best result for predictions based on the logistic regression was a sensitivity of 66.7% (44.7%; 84.4%) and a specificity of 80.4% (66.9%; 90.2%). Accuracy rates of fuzzy method and CART were higher [accuracy rate for fuzzy method and CART: 84% (73.7%; 91.4%), for logistic regression method: 73.3%, 95%-CI: (61.9%; 82.9%)]. CONCLUSIONS From a clinical point of view, the predictive ability of the three methods is not sufficiently large to justify use of these methods in daily practice. Other factors probably on the molecular level are needed for the prediction of lymph node metastasis.

Diagnostic analyses of cervical lymph nodes in patients with oral squamous cell carcinoma using CT and US

CT and US images of 24 patients with oral squamous cells carcinoma were studied retrospectively to clarify the characteristics finding of metastases in cervical lymph nodes. CT images of 201 lymph nodes were analyzed for patterns in appearance and maximum diameter on axial images. US findings of 45 lymph nodes were investigated with regard to internal echo. The metastatic nodes were found to be characterized by rim enhancement on CT and an heterogeneous appearance on US, while the features of non-metastatic nodes were an homogeneous appearance on CT with a density lower than that of the sternocleid mastoid muscle, and spot or septum patterns on US. Based on these results, we suggest new diagnostic criteria for metastatic cervical nodes in oral squamous cell carcinoma combining CT and US examinations.

Improved technique for evaluating oral free flaps by pinprick testing assisted by indocyanine green near-infrared fluorescence angiography

In head and neck surgery, free-flap reconstruction using a microvascular anastomosis is an indispensable option after tumor ablation. Because the success of free-flap reconstruction is enhanced by rapid identification and salvage of failing flaps, postoperative monitoring of free flaps is essential. We describe a new technique using indocyanine green (ICG) near-infrared angiography and pinprick testing to monitor intraoral free flaps. A solution of ICG (Diagnogreen, 5 ml) was intravenously injected, and scanning was performed with a near-infrared video camera system. Thirty seconds after ICG injection, a pinprick test was performed by placing a 24-gage needle through the dermis to the subcutaneous fat of the flap. Pinprick testing during ICG fluorescence imaging was performed in 30 patients. Flap perfusion was confirmed in all patients, and all flaps survived postoperatively. ICG fluorescence imaging demonstrated that flap perfusion was maintained.

Matrix-assisted laser desorption/ionization imaging mass spectrometry revealed traces of dental problem associated with dental structure

Periodontal disease is a serious dental problem because it does not heal naturally and leads to tooth loss. In periodontal disease, inflammation at periodontal tissue is thought as predominant, and its effect against tooth itself remains unclear. In this study, we applied matrix-assisted laser desorption/ionization imaging mass spectrometry (IMS) to teeth for the first time. By comparing anatomical structure of tooth affected with periodontal disease with normal ones, we analyzed traces of the disease on tooth. We found signals characteristic of enamel, dentin, and dental pulp, respectively, in mass spectra obtained from normal teeth. Ion images reconstructed using these signals showed anatomical structures of the tooth clearly. Next, we performed IMS upon teeth of periodontal disease. Overall characteristic of the mass spectrum appeared similar to normal ones. However, ion images reconstructed using signals from the tooth of periodontal disease revealed loss of periodontal ligament visualized together with dental pulp in normal teeth. Moreover, ion image clearly depicted an accumulation of signal at m/z 496.3 at root surface. Such an accumulation that cannot be examined only from mass spectrum was revealed by utilization of IMS. Recent studies about inflammation revealed that the signal at m/z 496.3 reflects lyso-phosphatidylcholine (LPC). Infiltration of the signal is statistically significant, and its intensity profile exhibited the influence has reached deeply into the tooth. This suggests that influence of periodontal disease is not only inflammation of periodontal tissue but also infiltration of LPC to root surface, and therefore, anti-inflammatory treatment is required besides conventional treatments.

Change of sonographic findings on cervical lymph nodes before and after preoperative radiotherapy

The aim of this study was to assess the changes in the power Doppler sonographic findings in patients with oral cancer undergoing chemotherapy and radiotherapy. We performed US examinations on 187 cervical lymph nodes (71 metastatic and 116 reactive nodes) excised from 52 patients before and after preoperative therapy. On Power Doppler images, we calculated the vascular index (VI) and evaluated the vascular pattern. We also assessed the diagnostic power using receiver operating characteristic (ROC) curve analysis. Irradiation caused an increase of the VI and better visualization of the vessels within the lymph node in the reactive nodes; however, in the metastatic nodes, the VI was not significantly different between that before and after irradiation. When the reader observed the images before irradiation, the area under an ROC curve (Az values) observed by B-mode sonography were closely similar to those obtained by B-mode plus power Doppler sonography. With both images before and after irradiation, the Az value obtained by B-mode plus power Doppler sonography was higher than that by B-mode sonography alone. After irradiation, the enhanced Doppler signals contributed to a better visualization of the vessels and a better detection of any vascular abnormalities.

End-to-side anastomosis to the external jugular vein: preservation of external jugular vein blood flow

v p the anastomosis of the artery, the vein of the donor flap is anastomosed to the external jugular vein. The anastomosis is he external jugular vein provides a long, free vessel that acilitates microsurgical anastomosis in free tissue transfers f the head and neck. However, it is liable to kink because of ts length, which increases the risk of venous thrombosis.1,2 arly in a conventional neck dissection the vein is identied and ligated near the inferior pole of the parotid gland. hen a microvascular free flap is to be used for recontruction, the entire external jugular vein is dissected and reserved with a suture-ligation at the upper end. Because f the prolonged duration of ischaemia before revascularisaion, clots can form in its lumen and may be found at the time f anastomosis. Even after revascularisation using an end-tond anastomosis, the decreased venous flow may accelerate enous thrombosis.3 We describe an end-to-side anastomois to the external jugular vein that preserves blood flow by voiding ligation and decreases the likelihood of thrombosis.

Three-dimensional computed tomographic analysis of variations of the carotid artery.

BACKGROUND Although the terms tortuous, coiling, and kinking have been used to describe the curvature of the carotid artery, the prevalence rates of these patterns have differed among studies. We morphologically evaluated the characteristics of the carotid artery by means of three-dimensional computed tomography (3DCT) to clarify the prevalence of tortuosity, coiling, and kinking. We present our results and discuss the clinical impact of our findings. METHODS A total 148 patients underwent contrast-enhanced CT (including 55 patients who underwent dynamic CT), and anatomical variations were analyzed on the basis of 3DCT images. RESULTS Among the 296 arteries, tortuosity was present in 254 (85.8%), coiling in 9 (3.0%), kinking in 3 (1.0%), and occlusion in 2 (0.7%). CONCLUSION 3DCT image reconstruction is an effective means for classifying morphological variations of the ICA and detecting abnormalities of the carotid artery. It can thereby potentially reduce the risk of serious complications during neck surgery.

Treatment of a Large Mandibular Ameloblastoma by Marsupialisation and Marginal Resection Preserves the Mandibular Inferior Border

Abstract Ameloblastomas are benign locally invasive odontogenic tumours. Involvement of the inferior border of the mandible in ameloblastomas usually requires segmental mandibulectomy. This report is of a 72-year-old man with a large mandibular ameloblastoma composed of a large cystic part and a solid multicystic part. A 2-stage operation, consisting of marsupialisation and subsequent marginal resection, enabled the preservation of the inferior mandibular border. There was no evidence of recurrence 55 months after the resection.