Tractography of the median nerve.

The median nerve is one of the most commonly affected peripheral nerves in various pathologies such as entrapment syndromes or transections. The diagnostic procedures applied in these situations are electromyography, physical examination methods, ultrasonography, and magnetic resonance imaging. Diffusion tensor imaging (DTI) has been used mostly in imaging the central nervous system (CNS) to visualize white matter tracts. Several studies have shown the clinical applications of DTI in neuronal disorders such as stroke, epilepsy, and CNS tumors. Recently, peripheral nerves have been visualized with DTI. Also, in several pathologies such as carpal tunnel syndrome and transection of the median nerve, on postoperative follow-up anisotropy indexes were shown to be affected. However, new studies with larger series are needed.

Diffusion tensor imaging of the normal prostate at 3 Tesla.

The aim of this study was to assess the feasibility of diffusion tensor imaging (DTI) of the prostate and to determine normative fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of healthy prostate with a 3-Tesla magnetic resonance imaging (MRI) system. Thirty volunteers with a mean age of 28 (25-35) years were scanned with a 3-Tesla MRI (Intera Achieva; Philips, The Netherlands) system using a six-channel phased array coil. Initially, T2-weighted turbo spin-echo (TSE) axial images of the prostate were obtained. In two subjects, a millimetric hypointense signal change was detected in the peripheral zones on T2-weighted TSE images. These two subjects were excluded from the study. DTI with single-shot echo-planar imaging (ssEPI) was performed in the remaining 28 subjects. ADC and FA values were measured using the manufacturer supplied software by positioning 9-pixel ROIs on each zone. Differences between parameters of the central and peripheral zones were assessed. Mean ADC value of the central (1.220 +/- 0.271 x 10(-3) mm(2)/s) was found to be significantly lower when compared with the peripheral gland (1.610 +/- 0.347 x 10(-3) mm(2)/s) (P < 0.01). Mean FA of the central gland was significantly higher (0.26), compared with the peripheral gland (0.16) (P < 0.01). This study shows the feasibility of prostate DTI with a 3-Tesla MR system and the normative FA and ADC values of peripheral and central zones of the normal prostate. The results are compatible with the microstructural organization of the gland.

Diffusion tensor imaging and tractography of median nerve: normative diffusion values.

OBJECTIVE: The purposes of this study were to visualize the human median nerve on diffusion tensor imaging and to determine the normal fractional anisotropy (FA) value and apparent diffusion coefficient (ADC) of the normal median nerve. SUBJECTS AND METHODS: The wrists of 20 healthy volunteers and of two patients with carpel tunnel syndrome were examined with a 3-T MRI system with a standard eight-channel sensitivity-encoding head coil. Diffusion tensor imaging was performed with a spin-echo echo-planar sequence. A T1-weighted sequence was performed for anatomic reference. After tractography, the FA value and ADC of the whole nerve were calculated automatically. Manual focal measurements also were obtained at the levels of the flexor retinaculum, wrist, and forearm. RESULTS: We visualized the median nerve with MR diffusion tensor tractography and followed the nerve for approximately 77.5 mm. We found the normative diffusion values of the median nerve were an FA of 0.709 +/- 0.046 (SD) and an ADC of 1.016 +/- 0.129 x 10(-3) mm2/s. There was a statistically significant difference between the FA values obtained at the level of the flexor retinaculum and the values obtained from the other parts of the median nerve (p < 0.0001). We found a decrease in FA value (p < 0.01) and an increase in ADC (p < 0.05) with advancing age. CONCLUSION: The normative diffusion values of the human median nerve can be used as a reference in evaluation, diagnosis, and follow-up of entrapment, trauma, and regeneration of the median nerve.

Breast myxoma: Radiologic and histopathologic features.

Myxomas are benign mesenchymal tumors, which rarely develop in the breast. Histologically, stellate, round, and spindle-shaped cells with vesicular nuclei and scant cytoplasm are scattered in the myxoid stroma. We present a case of this rare type of breast tumor with sonographic and mammographic findings.

Diagnostic contribution of virtual endoscopy in diseases of the upper airways.

PURPOSE: Virtual endoscopy (VE) is a new diagnostic tool that generates 3-dimensional (3D) views of a lumen by exploiting cross-sectional images. The purpose of this study was to evaluate the usefulness of VE as a diagnostic tool in the diseases of the larynx and pharynx. MATERIALS AND METHODS: Twenty-two patients with a mean age of 57 years were included in the study. The patients underwent larynx examination, optical endoscopy (OE), and computed tomography (CT) of the larynx. Later, VE was produced from the CT images. RESULTS: Eight patients had larynx carcinoma, a 5-year-old patient had a laryngeal web, a 43-year-old man had fish bone stuck in his submucosal layer, 10 patients were normal, and the remaining two patients were under follow-up for treated nasopharynx carcinoma and had no evidence for recurrence. VE showed the laryngeal tumor in seven patients and the laryngeal web in one patient, but failed to show a plaquelike tumor and the fishbone within the submucosa. CONCLUSIONS: Our findings suggest that VE is a useful and complimentary method of 3D imaging in the diseases compromising the laryngeal lumen. Furthermore, it may be superior to OE in severe stenosis or obstructions where the endoscope cannot be passed through.

Do we really need plain and soft-tissue radiographies to detect radiolucent foreign bodies in the ED?

OBJECTIVE: The objective of this study was to compare 3 imaging techniques-plain radiography, soft-tissue radiography, and ultrasonography-in detecting nonradiopaque foreign bodies in soft tissue. METHODS: In this randomized, blinded, and descriptive in vitro study, 40 chicken thighs with 2 types of nonradiopaque foreign bodies (wood and rubber) and 40 chicken thighs as part of a control group were evaluated to detect soft-tissue foreign bodies with plain radiography, soft-tissue radiography, and high-frequency ultrasonography. RESULTS: The overall sensitivity, specificity, as well as positive predictive and negative predictive values of plain radiography for both nonradiopaque foreign bodies were 5%, 90%, 33%, and 48%, respectively; those of soft-tissue radiography for both nonradiopaque foreign bodies were 5%, 90%, 33%, and 48%, respectively; and those of ultrasonography for both nonradiopaque foreign bodies were 90%, 80%, 81%, and 89%, respectively. CONCLUSIONS: In this experimental model, the results show that high-frequency ultrasonography is superior to plain and soft-tissue radiographies and that the latter 2 techniques are similarly poor at detecting nonradiopaque foreign bodies.

Echo contrast-enhanced power Doppler ultrasonography for assessment of angiogenesis in renal cell carcinoma.

OBJECTIVE: Tumoral growth is an angiogenesis-dependent event. Although there are studies about the importance of histopathologic angiogenesis in various malignancies, the assessment of the angiogenesis by radiologic techniques is not well established. The aim of this study was to investigate the efficacy of echo contrast-enhanced power Doppler ultrasonography (PDUS) in determining the angiogenic status of renal cell carcinoma (RCC). METHODS: Power Doppler ultrasonography was performed before and after intravenous administration of an echo contrast agent in 42 patients with renal masses. Twenty-one of these renal masses were diagnosed as RCC histopathologically, and these 21 patients were reevaluated retrospectively. The color pixel ratios of selected images were calculated as the ratio of the number of pixels showing power Doppler signals to the total number of pixels within the lesion. The results were compared with the histopathologic microvessel density (MVD). RESULTS: A significant correlation was found between color pixel ratio and MVD values in both PDUS techniques. The use of the echo contrast agent improved this correlation and P values (Spearman rho from 0.436 to 0.551; P from .048 to .01). CONCLUSIONS: Color pixel ratio values reflect the MVD in RCC. Therefore, these results suggest that preoperative quantification of angiogenesis can be possible with the help of PDUS in RCC.