This study suggests MDCT as a triage tool may identify patients who will benefit from DBE and aid the endoscopist in choosing the most efficient route.
Substance poisoning, such as toluene intoxication, has seldom been reported in the relevant literature. The documented cerebral neuroimaging has mostly described reversible symmetrical white matter changes in both the cerebral and cerebellar hemispheres. This paper presents 2 patients with toluene poisoning, whose brain magnetic resonance imaging studies showed a similar picture that included extra involvement over the corpus callosum; however, such corpus callosum involvement has never been mentioned and is quite rare in the literature. We discussed the underlying neuropathological pathways in this article. Hopefully, these cases will provide first-line clinicians with some valuable information with regard to toluene intoxication and clinical neuroimaging presentations.
Objective: The present study evaluated and analyzed apparent diffusion coefficients (ADCs) from partitions through a fuzzy C-means (FCM) technique for distinguishing nodal metastasis in head and neck cancer. Methods: MRI studies of 169 lymph node lesions, dissected from 22 patients with a histopathologically confirmed lymph node status, were analyzed using in-house software developed using MATLAB® (The MathWorks® Inc., Natick, MA). A radiologist manually contoured the lesions, and ADCs for each lesion were divided into two (low and high) and three (low, intermediate and high) partitions by using the FCM clustering algorithm. Results: The results showed that the low-value ADC clusters were more sensitive (95.7%) in distinguishing malignant from benign lesions than the whole-lesion mean ADC values (78.3%), while retaining a high specificity (approximately 90%). Moreover, receiveroperating characteristic curves demonstrated that the low-value ADC clusters used as a predictor of malignancy for lymph nodes could achieve a higher area under the curve (0.949 and 0.944 for two and three partitions, respectively). Conclusion: The segmentation by ADC values of lesions through the FCM technique enables the efficient characterization of the lymph node pathology and can help distinguish malignant from benign lymph nodes. Advances in knowledge: Tumour heterogeneity may degrade the prediction of metastatic lymph nodes that involves using mean region-of-interest ADC values. The clustering of ADC values in lesions by using FCM can improve the diagnostic accuracy of nodal metastasis and reduce interreader variance.
Positron-emission tomography/computed tomography (PET/CT) has been proposed as a means to enhance the pretreatment evaluation of cervical lymph node status in patients with nasopharyngeal carcinoma (NPC). We conducted a prospective study to compare PET/CT and enhanced CT for the detection of retropharyngeal lymph node (RLN) metastasis in NPC, and to ascertain the factors that affect its diagnostic performance. Our study population was made up of 33 patients—24 men and 9 women, aged 30 to 81 years (mean: 52)—with newly diagnosed NPC who had been treated over a 2-year period. All patients underwent enhanced CT first, followed by unenhanced 18F-fluorodeoxyglucose (FDG) PET/CT. The detection rate of RLN metastasis on PET/CT was significantly lower than that on enhanced CT (36.4 vs. 75.8%; p < 0.001). A total of 25 of 26 nodes with a discordant finding were negative on PET/CT; they included 13 metastatic lymph nodes with low FDG uptake, 9 that were located close to the primary tumor, 2 that were confluent RLNs, and 1 that was adjacent to the physiologic FDG-avid prevertebral muscle. The maximum standardized uptake value (SUVmax) of RLNs was positively correlated with the minimum axial diameter (r = 0.803, p < 0.001). The PET/CT detection rate was 0% for lymph nodes smaller than 5 mm, 9% for those 5 to 10 mm, and 73% for those 1 cm or larger. The detection rate of PET/ CT at level C1 was significantly lower than that at C2 (22 vs. 67%; p = 0.035). We conclude that unenhanced PET/CT is markedly inferior to enhanced CT for detecting RLN metastasis in NPC, especially in lymph nodes with a minimum axial diameter of less than 1 cm and those in proximity to the primary tumor. Using enhanced CT in PET/CT is justified to improve the recognition of RLN metastasis in patients with NPC.
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