Bengi Gurses

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.

Diagnostic utility of DTI in prostate cancer

PURPOSE The aim of this study was to compare the diffusion tensor parameters of prostate cancer, prostatitis and normal prostate tissue. MATERIALS AND METHODS A total of 25 patients with the suspicion of prostate cancer were included in the study. MRI was performed with 3 T system (Intera Achieva, Philips Medical Systems, The Netherlands). T2 TSE and DTI with ss-EPI were obtained in each subject. TRUS-guided prostate biopsy was performed after the MRI examination. Images were analyzed by two radiologists using a special software system. ROIs were drawn according to biopsy zones which are apex, midgland, base and central zone on each sides of the gland. FA and ADC values in areas of cancer, chronic prostatitis and normal prostate tissue were compared using Students t-test. RESULTS Histopathological analysis revealed carcinoma in 68, chronic prostatitis in 67 and was reported as normal in 65 zones. The mean FA of cancerous tissue was significantly higher (p<0.01) than the FA of chronic prostatitis and normal gland. The mean ADC of cancerous tissue was found to be significantly lower (p<0.01), compared with non-cancerous tissue. CONCLUSION Decreased ADC and increased FA are compatible with the hypercellular nature of prostate tumors. These differences may increase the accuracy of MRI in the detection of carcinoma and to differentiate between cancer and prostatitis.

Diffusion tensor imaging of the kidney at 3 Tesla: normative values and repeatability of measurements in healthy volunteers

PURPOSE To evaluate the feasibility of renal diffusion tensor imaging and determine the normative fractional anisotropy and apparent diffusion coefficient values at 3 Tesla magnetic resonance imaging (MRI) using parallel imaging and free breathing technique. MATERIALS AND METHODS A total of 52 young healthy volunteers with no history of renal disease were included in the study. MRI examinations were performed with 3 Tesla MRI equipment, using six-channel phased array SENSE Torso coil. In all subjects, T2-weighted turbo spin echo and diffusion tensor imaging using single shot echo planar imaging sequences were obtained in the coronal plane with free breathing. Field of view, slice thickness, and slice gap values were identical for both sequences for anatomic correlation during analysis of diffusion tensor imaging data. Parallel imaging method was used with a SENSE factor of 2. Diffusion tensor parameters of the cortex and medulla were determined and the intra- and inter-observer measurement variances were calculated. RESULTS The mean fractional anisotropy of the medulla was significantly higher than that of the cortex, whereas the mean apparent diffusion coefficient of the medulla was lower when compared with that of the cortex. According to the two-sided paired samples Students t test, the intra- and inter-observer measurements correlated well. CONCLUSION This study shows the feasibility of renal diffusion tensor imaging and repeatibility of diffusion tensor parameter measurements in 3 Tesla MRI.

Nodule or Pseudonodule? Differentiation in Hashimoto's Thyroiditis with Sonoelastography

Fine needle aspiration biopsy (FNAB) is the gold standard for the diagnosis of lymphoma in Hashimotos thyroiditis and is able to differentiate between benign, inflammatory or malignant nodules, classifying them as either true nodules or pseudonodules. This technique is, however, invasive. The present study aimed to differentiate pseudonodules from true nodules by sonoelastography, a noninvasive technique, in 54 patients with Hashimotos thyroiditis. The accuracy of sonoelastography to differentiate between true or pseudonodules was compared with the gold standard FNAB and with grey scale ultrasonography. The nodules were categorized into three groups: non-demarcated hypoechogenic, demarcated hyperechogenic, and demarcated hypoechogenic. Sonoelastography findings were concordant with the cytopathological results and demonstrated that sonoelastography was able to detect true thyroid nodules often misdiagnosed by conventional grey scale ultrasonography. Sonoelastography was found to have increased sensitivity for true nodule diagnosis compared with conventional grey scale ultrasonography and may eliminate unnecessary FNABs being carried out.

Acute aortic dissection with painless paraplegia: report of 2 cases

Acute aortic dissection is often a life-threatening event that usually presents as a sudden, severe, exquisitely painful, ripping sensation in the chest or back. There are a few reports of atypical findings or no pain in the literature. We report 2 patients with painless acute aortic dissection who presented to the emergency department (ED) with sudden onset paraplegia.

Imaging features of a cecal lipoma as a lead point for colo-colonic intussusception

Intussusception is a rare occurrence in the adult population with most of the cases seen during the childhood period. Compared with the pediatric intussusceptions, there is more often an underlying cause in adults. Lipoma as a lead point for colonic intussusception is rare. Ultrasound may be helpful in the diagnosis, but computed tomography is more reliably used for differential diagnosis. An adult patient with colo-colonic intussusception diganosed with ultrasound and confirmed with computed tomography is presented.

Diffusion tensor imaging in carpal tunnel syndrome.

PURPOSE We aimed to investigate the efficacy of diffusion tensor imaging in the diagnosis of carpal tunnel syndrome and to obtain a quantitative parameter that may contribute to the diagnosis. MATERIALS AND METHODS The median nerves in 57 wrists of 38 patients diagnosed as carpal tunnel syndrome and 30 wrists of 24 normal subjects were prospectively evaluated with a 3T Philips scanner, using standard 8-channel SENSE head coil. Diffusion tensor imaging was performed using spin echo-echo planar imaging. For anatomical reference, a T1-weighted sequence was acquired. Fractional anisotropy and apparent diffusion coefficient measurements were done focally at the carpal tunnel level and from whole median nerve. RESULTS In carpal tunnel syndrome patients, both focal carpal tunnel and whole nerve measurements demonstrated statistically significantly lower fractional anisotropy values than normal subjects (P < 0.001). No statistically significant difference was observed in apparent diffusion coefficient measurements. The cut-off value obtained by receiver operator characteristics analysis was 0.554 for focal carpal tunnel fractional anisotropy (sensitivity, 80%; specificity, 80%) and 0.660 for whole nerve fractional anisotropy (sensitivity, 82%; specificity, 80%) measurement. CONCLUSION Diffusion tensor imaging may contribute to the diagnosis of carpal tunnel syndrome on the basis of fractional anisotropy measurements.

Diffusion tensor imaging in the differentiation of adrenal adenomas and metastases.

PURPOSE To determine the utility of diffusion tensor imaging for the differentiation of adrenal adenomas and metastases. MATERIALS AND METHODS Thirty-three patients with a mean age of 59 years were included in this study. Each subject presented with a single adrenal lesion (19 adenomas, 14 metastases). Magnetic resonance imaging (MRI) was performed in the coronal plane using a 3 Tesla MRI and a six-channel phased array SENSE torso coil. T1-weighted in-phase and opposed-phase, T2-weighted turbo spin-echo, and single-shot echo-planar diffusion tensor imaging (DTI) sequences were used for image acquisition. To determine apparent diffusion coefficients (ADC) and fractional anisotropy (FA) values of adrenal lesions, coronal T2-weighted images were used as anatomical references and to localize regions of interest on DTI images. The signal intensity (SI) indices were obtained from in-phase/opposed-phase images by a radiologist blinded to the DTI findings. The DTI parameters were determined by a different radiologist. The SI indices and the differences in FA and ADCs between adenomas and metastases were compared. Analyses of receiver operating characteristics (ROC) were performed to determine the area under the curve (AUC). RESULTS The SI index of adenomas was found to be significantly higher than the value determined for metastases. Moreover, the median FA value of adrenal adenomas was found to be significantly higher than that of metastases. No statistically significant difference was observed in the ADCs between adenomas and metastases. Furthermore, no significant correlation was found among the SI index and the measured DTI parameters. Based on ROC analyses, the AUC was found to be 0.936 in FA measurements with a 95% confidence interval. The cutoff value obtained from this analysis was 0.40 with maximum sensitivity and specificity values of 74% and 88%, respectively. CONCLUSION Although no significant difference was observed in the ADCs between adrenal adenomas and metastases, the FA values differed significantly. The FA values may have the potential to differentiate between adrenal adenomas and metastases, which is a possibility that should be validated by further research.

Retroperitoneal Schwannoma: A Rare Case

Introduction. Schwannomas are quiet rare in the retroperitoneal region. Here, we describe an incidentally detected retroperitoneal schwannoma in the abdominal computerized tomography (CT) of a patient with acute appendicitis. Case Presentation. A 38-year-old woman was admitted to the emergency service with the complaints of progressive abdominal pain and nausea for the last 24 hours. Abdominal examination was compatible with acute abdomen. Acute appendicitis was diagnosed by CT. During CT evaluation, a round shaped soft-tissue mass at the retroperitoneal area inferior to the right kidney was detected, The mass was resected and histology revealed schwannoma. Conclusion. Rare tumoral lesions with benign course such as schwannoma can be detected incidentally.

Evaluation of the Gastro-Oesophageal Junction: Defining the Incompetent Cardio-Oeosophageal Angle Non-Invasively with Ultrasound and Computerized Tomography

This study aimed to demonstrate the presence of gastro-oesophageal reflux disease (GORD) non-invasively using ultrasound (US) and computerized tomography (CT). Intra-abdominal oesophageal length (IAOL) and cardio-oesophageal angle (COA) were measured by US in 25 patients with known reflux and in 25 healthy subjects (control group). CT images of 42 patients with reflux disease and 44 controls were reviewed retrospectively, and IAOL and COA were measured on curved multiplanar format images. Using a cutoff value for IAOL of 20.5 mm, the sensitivity to detect GORD with US was 96% and the specificity was 80% and, with CT, the sensitivity was 95% and the specificity was 78%. A cut-off value of 138.5° for COA yielded sensitivity and specificity values for GORD detection of 76% and 72% with US and 83% and 80% with CT, respectively. In conclusion, with equivocal diagnostic findings, IAOL and COA are useful parameters that can be determined non-invasively by US or CT and may aid diagnosis and treatment choices for patients with suspected GORD.