Teh-Chen Wang

Dysphagia in Patients with Nasopharyngeal Cancer After Radiation Therapy: A Videofluoroscopic Swallowing Study

This study evaluated swallowing status and the factors influencing swallowing in patients with nasopharyngeal carcinoma (NPC) after radiation therapy. During the period from July 1995 to June 1999, this cross-sectional study used videofluoroscopic swallowing study (VFSS) to evaluate 184 NPC patients who had completed radiation therapy [113 cases had completed radiation therapy ≤12 months prior to evaluation (acute group) and 71 cases had completed radiation therapy >12 months prior to evaluation (chronic group)]. The numbers of patients with tumors in each of the four stages were as follows: 24 in stage I, 45 in stage II, 41 in stage III, and 74 in stage IV. Swallowing abnormalities of the acute and chronic groups were correlated with multiple variables, including gender, age, the stage of the tumor, use of either neoadjuvant chemotherapy or radiosensitizer, and radiation modality. The analytical results indicated that the chronic group had a significantly higher proportion of swallowing abnormalities. Radiation modality, chemotherapy, and tumor staging were not significantly associated with swallowing dysfunction. Trend analysis revealed a progressive deterioration of most parameters of swallowing function in this group of patients. These findings indicate that swallowing function continues to deteriorate over time, even many years after radiation therapy in patients with NPC. Our results indicate that the time elapsed since radiation therapy correlates with the severity of dysphagia in NPC patients.

Intrapulmonary Bronchogenic Cysts: Computed Tomography, Clinical and Histopathologic Correlations

BACKGROUND/PURPOSE Bronchogenic cysts (BCs) are usually located in the mediastinum and they occur less commonly in the lung parenchyma. This study investigated the findings from computed tomography (CT) images, clinical presentation and histopathologic findings of intrapulmonary BCs. METHODS From the last 7 years, the CT images of 20 patients (12 females, 8 males; mean age, 38.8 +/- 21.7 years; median age, 34 years) with intrapulmonary BC were available. Contrast-enhanced CT findings were characterized and correlated with clinical presentation and histopathologic findings (using Fishers exact tests). RESULTS The majority of intrapulmonary BCs were subpleural in location (55%), in the lower lobes (60%), symptomatic (80%), and in adults (90%). Three CT patterns were identified: cyst with content of fluid attenuation (9 patients), cyst with air and fluid content (9 patients), cyst with content of soft tissue attenuation (2 patients). Preoperative diagnosis of intrapulmonary BC was correct in only 20% using the CT criteria of cysts with fluid attenuation and without anomalous blood supply. Cysts with air component were significantly larger than those without air component (p = 0.0452), but cyst size and air component were not correlated with clinical presentation. Surrounding infiltration or thick wall on CT were significantly correlated with the presence of any clinical symptom (p = 0.014) or fever (p = 0.042). CT findings of surrounding consolidation, ground glass opacity or thick wall were significantly correlated with chronic inflammation or pneumonic change on histopathology (p = 0.0008). CONCLUSION There is a wide spectrum of intrapulmonary BCs that have CT findings that are correlated with clinical presentations and histopathologic findings.

Computer-aided diagnosis of breast DCE-MRI using pharmacokinetic model and 3-D morphology analysis

Three-dimensional (3-D) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) consists of a large number of images in different enhancement phases which are used to identify and characterize breast lesions. The purpose of this study was to develop a computer-assisted algorithm for tumor segmentation and characterization using both kinetic information and morphological features of 3-D breast DCE-MRI. An integrated color map created by intersecting kinetic and area under the curve (AUC) color maps was used to detect potential breast lesions, followed by the application of a region growing algorithm to segment the tumor. Modified fuzzy c-means clustering was used to identify the most representative kinetic curve of the whole segmented tumor, which was then characterized by using conventional curve analysis or pharmacokinetic model. The 3-D morphological features including shape features (compactness, margin, and ellipsoid fitting) and texture features (based on the grey level co-occurrence matrix) of the segmented tumor were obtained to characterize the lesion. One hundred and thirty-two biopsy-proven lesions (63 benign and 69 malignant) were used to evaluate the performance of the proposed computer-aided system for breast MRI. Five combined features including rate constant (kep), volume of plasma (vp), energy (G1), entropy (G2), and compactness (C1), had the best performance with an accuracy of 91.67% (121/132), sensitivity of 91.30% (63/69), specificity of 92.06% (58/63), and Az value of 0.9427. Combining the kinetic and morphological features of 3-D breast MRI is a potentially useful and robust algorithm when attempting to differentiate benign and malignant lesions.

2-D time-of-flight (TOF) MRA of thrombophlebitis of upper extremity and subclavian veins. A case report.

In this report, the authors present a case of segmental thrombosis of left subclavian vein that was inaccessible to conventional venography and inconclusive in magnetic resonance techniques (spin echo, gradient echo) but was clearly demonstrated by two-dimensional time-of-flight magnetic resonance angiography (2D TOF MRA). This technique is very sensitive to detect slow flow or partial occlusion of the vessels and is of great help in solving the problem of axillary-subclavian venous obstruction or thrombophlebitis.

A 2-Year Follow-Up of Swallowing Function After Radiation Therapy in Patients With Nasopharyngeal Carcinoma

OBJECTIVE To evaluate over a 2-year period the serial swallowing function of patients with nasopharyngeal carcinoma (NPC) after completing radiotherapy (RT). DESIGN Prospective longitudinal follow-up. SETTING University hospital. PARTICIPANTS Patients with NPC (N=76) referred for RT: 53 of them at 1 year after RT, and 23 at 2 years after RT. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Participants completed a questionnaire and had a video-recorded fluoroscopic swallowing study before RT and 1 month, 1 year, and 2 years after RT. RESULTS The highest incidence of dysphagia symptoms and retropharyngeal soft tissue swelling occurred in the first month after RT and decreased over time. Pharyngeal transit time was prolonged continuously up to 1 year after RT. Epiglottic vallecular stasis and pharyngeal mucosal coating were worst in the first month after RT and stable afterwards. Aspiration was uncommon during the first 2 years after RT. CONCLUSIONS At a 2-year follow-up after RT, patients with NPC had a progressively increasing pharyngeal transit time, although the subjectively identified symptoms of dysphagia decreased after the first month after RT.