Diffusion Tensor Imaging in Parenchymal Neuro-Behçet's Disease.

Introduction: Parenchymal Neuro-Behçet's disease (p-NBD) usually presents with a characteristic lesion in the mesodiencephalic region. However, there is a lack of information regarding the axonal integrity of normal-appearing white matter in p-NBD. Diffusion tensor imaging (DTI) is based on the properties of diffusivity and anisotropy that indicate the integrity of axons. The primary objective of the study was to compare p-NBD patients to healthy controls using diffusion tensor magnetic resonance imaging (DTI-MRI). Methods: The study enrolled parenchymal p-NBD patients who maintained stable disease status for 12 months. Healthy controls were chosen from a population with a similar age and gender distribution. Axial DTI was acquired using single-shot echo-planar imaging. Group analyses were carried out using the track-based spatial statistics tool of FMRIB software library (FSL). Correlations between DTI parameters and clinical outcomes were analyzed in the patient group. Results: We recruited 12 patients with p-NBD and 12 healthy individuals. We found significant fractional anisotropy (FA), mean diffusivity (MD), and radial diffusivity (RD) differences in the superior longitudinal fasciculus, superior corona radiata, anterior corona radiata, body and genu of the corpus callosum, external capsule, and anterior limb of the internal capsule, mainly in the frontal white matter. Conclusion: Patients with p-NBD exhibit significant DTI alterations in the otherwise normal-appearing frontal association tracts. This study may contribute to a better understanding of the neuropsychological impairment pattern in patients with p-NBD, which is often associated with frontal cognitive networks.

Intravoxel Incoherent Motion of Colon Cancer Liver Metastases for the Assessment of Response to Antiangiogenic Treatment: Results from a Pilot Study.

OBJECTIVE: This study was aimed at evaluating the intravoxel incoherent motion (IVIM) parameter alterations of liver metastases of colorectal carcinoma (CRC) during antiangiogenic bevacizumab combination therapy. METHODS: Twenty-five patients with CRC liver metastases treated with bevacizumab in combination with FOLFOX-or-FOLFIRI protocols were enrolled in the study. MRI was performed using a 1.5-tesla scanner pre-treatment (PT) and at 3, 6, and 9 months of therapy. Routine abdominal MRI sequences and an IVIM-DWI (diffusion-weighted imaging) sequence were obtained. The IVIM-DWI sequence was executed with 16 b-values varying from 0 to 1,400 s/mm2. The mean values of apparent diffusion coefficient (ADC), true diffusion (D), pseudodiffusion (D*), and perfusion fraction (f) of each metastasis were obtained for all b-values, and the time-related changes were recorded to analyze the chronologic responses to antiangiogenic therapy. The RECIST 1.1 criteria were used for the evaluation of treatment response. RESULTS: The diameters of the metastases diminished significantly at 9 months when compared with PT (p = 0.03). The D (p = 0.10) and ADC (p = 0.21) values of the metastases increased at 9 months of therapy. D* was the highest at 3 months (p =0.24); it decreased at 6 (p =0.97) and 9 months (p =0.87) of therapy. The f value had peaked at 3 months (p =0.51) and started to decrease thereafter. At 6 months, f decreased to the lowest values (p =0.12). CONCLUSION: IVIM parameters, particularly the perfusion fraction, may quantitatively reflect the response to antiangiogenic treatment. The antiangiogenic response manifests after 3 months of therapy before the RECIST-related response.

Intravoxel Incoherent Motion Parameters for Assessing the Efficiency of Locoregional Bridging Treatments before Liver Transplantation.

OBJECTIVE: To evaluate the diagnostic accuracy of Intravoxel Incoherent Motion (IVIM) parameters for assessment of tumor response after locoregional treatment (LRT) of hepatocellular carcinoma (HCC). METHODS: Fifteen patients with HCC who had undergone LRTs (11 transarterial radioembolization, 4 transarterial chemoembolization) were included. In addition to routine upper abdominal magnetic resonance imaging sequences, IVIM with 16 different b values and conventional diffusion weighted imaging with 3 different b factors were obtained immediately before and 8 weeks after LRTs. Magnetic resonance imaging response was evaluated according to modified Response Evaluation Criteria in Solid Tumors (mRECIST) and HCCs were categorized into 2 subgroups, responders and nonresponders. Quantitatively, the number of diffusion-changes were calculated with apparent diffusion coefficient (ADC) and IVIM parameters, including mean D (true diffusion coefficient), pseudo-diffusion coefficient associated with blood flow, and f (perfusion fraction) values. Subsequently, the pre- and post-treatment parameters were compared using the Mann-Whitney U test. RESULTS: Considering all HCCs, a significant decrease was observed according to mRECIST criteria (-38.43 ± 16.49). The ADC and D values after LRTs were significantly higher than those of the preceding ones. The f values after LRTs were significantly lower than those of pre-treatment. In the responders group, ADC and D values were significantly increased and f values were significantly decreased after LRTs. No difference of statistical significance was achieved in the nonresponders group. CONCLUSIONS: ADC values and IVIM parameters appear to reflect the response of LRTs as effectively as those of mRECIST. This promises new horizons in the management of pretransplant patients, especially in renal insufficiency clinical settings, owing to the elimination of contrast media administration.

Value of Intravoxel Incoherent Motion for Hepatocellular Carcinoma Grading.

BACKGROUND: To evaluate the diagnostic accuracy of intravoxel incoherent motion (IVIM) parameters in estimation of hepatocellular carcinoma (HCC) grading. MATERIALS AND METHODS: Twenty-nine patients with histopathologically diagnosed as 42 HCC at explant were included in this retrospective study. All patients were examined by 1.5T magnetic resonance imaging with the use of 4-channel phased array body coil. In addition to routine pre- and postcontrast sequences, IVIM (16 different b factors varying from 0 to 1300 s/mm2) and conventional diffusion-weighted imaging (3 different b factors of 50, 400, 800 s/mm2) were obtained with single-shot echo planar spin echo sequence. Apparent diffusion coefficient (ADC) and IVIM parameters including mean D (true diffusion coefficient), D* (pseudo-diffusion coefficient associated with blood flow), and f (perfusion fraction) values were calculated. Histopathologically, HCC was classified as low (grade 1, 2) and high (grade 3, 4) grade in accordance with the Edmondson-Steiner score. Quantitatively, ADC, D, D*, and f values were compared between the low- and high-grade groups by Student t test. The relationship between the parameters and histologic grade was analyzed using the Spearman's correlation test. To evaluate the diagnostic performance of the parameters, receiver operating characteristic analysis was performed. RESULTS: High-grade HCCs had significantly lower ADC and D values than low grade groups (P = .005 and P = .026, retrospectively); ADC and D values were inversely correlated with tumor grade (r = -0.519, P = .011, r = -0.510, P = .026, respectively). High-grade HCCs had significantly higher f values when compared with the low-grade group (P = .005). The f values were positively correlated with tumor grade (r = 0.548, P = .007). The best discriminative parameter was f value. Cut-off value of 32% of f values showed sensitivity of 75.6% and a specificity of 73.5%. CONCLUSION: ADC values and IVIM parameters such as f values appear to reflect the grade of HCCs.

The Utility of Noninvasive Scoring Systems for Prediction of Hepatic Steatosis in Liver Transplantation Donor Candidates.

BACKGROUND: The degree of liver steatosis is an important factor for donor selection in living donor liver transplantation. Multidetector computed tomography (MDCT) has long been used in many transplantation centers to determine donor liver steatosis. Noninvasive scoring methods based on laboratory tests have been investigated as potential methods for altering liver biopsy and imaging techniques in evaluating the liver steatosis. In this study, we assess the utility of several noninvasive methods for the evaluation of donor hepatosteatosis. In comparison, MDCT was used for the evaluation of liver steatosis. METHODS: A total of 205 donor candidates with significant hepatosteatosis were included in the study and divided into 4 groups according to the degrees of steatosis as measured by MDCT (mild, mid- to moderate, moderate to severe, and severe). In comparison, the aspartate aminotransferase-platelet ratio index (APRI), nonalcoholic fatty liver disease fibrosis score, BARD score, and FIB-4 scores were calculated. RESULTS: The diagnostic performance of APRI in prediction of all degrees of hepatosteatosis on MDCT was significantly higher (P < .01). The BARD score showed the second best performance (P = .018), whereas FIB-4 and nonalcoholic fatty liver disease fibrosis score were not correlated with degree of liver steatosis on MDCT. CONCLUSION: Some noninvasive scoring methods including APRI and BARD score seem to be more beneficial for the detection of hepatic steatosis in donor candidates and may reduce the need for other invasive and expensive diagnostic techniques.

Body Mass Index and Unenhanced CT as a Predictor of Hepatic Steatosis in Potential Liver Donors.

BACKGROUND: In living-donor liver transplantation, donor hepatic steatosis is crucial for both the donor and the recipient. Body mass index (BMI) and the unenhanced computed tomography liver attenuation index (CT LAI) are noninvasive methods to predict hepatic steatosis in living-donor liver candidates. AIM: To analyze the diagnostic accuracy of CT LAI in conjunction with different BMI values for macrovesicular steatosis in living-donor liver candidates. METHODS: A total of 264 potential liver donors were included. The diagnostic accuracy of 2 CT LAI cut-offs and 3 BMI cut-off values for the assessment of hepatic steatosis ≥15% and ≤5% was determined. RESULTS: Using CT LAI, the area under the receiver operating characteristic curve was 0.97 (95% CI = 0.89-0.99) for hepatic steatosis ≥15% in donors with BMI <25 kg/m2. For detecting hepatic steatosis ≥15%, a CT LAI ≤0 had specificities of 100%, 76.2%, and 55.6% and positive predictive values of 100%, 95.5%, and 93.5% for patients with BMI values <25 kg/m2, 25 to 29.9 kg/m2, and ≥30 kg/m2, respectively. According to logistic regression analyses, only CT LAI ≤0 was found to be independently associated with hepatic steatosis ≥15%. CONCLUSIONS: In donors with BMI <30 kg/m2 and a CT LAI value >6, liver biopsy might be avoided. Biopsy may be reserved solely for donors with CT LAI value >0 and BMI ≥30 kg/m2 as the diagnostic accuracy of computed tomography for predicting hepatic steatosis decreases with increasing BMI.

Value of Imaging Findings in the Prediction of Microvascular Invasion in Hepatocellular Carcinoma.

BACKGROUND: The purpose of this study was to determine the utility of some imaging findings in predicting microvascular invasion (MVI) and hepatocellular carcinoma (HCC) recurrence risk after liver transplantation. METHOD: This retrospective study included 123 patients with histopathologically proven HCC at explant. All HCCs were classified as MVI positive (group I) or negative (group II) based on histopathological findings. In each group, multifocality, largest tumor size, bulging (tumor causing liver capsule expansion), beak sign (the acute angle between the tumor and liver parenchyma), and diffusion restriction on diffusion weighted images (DWI) were evaluated. These findings were compared between the groups by Student's t test. The relation between the parameters and MVI was analyzed by using the Spearman's correlation test. RESULTS: Of the total patients, 30.1% had MVI (group I) and 69.9% (group II) did not have MVI. Presence of beak sign (P ≤ .005), bulging sign (P = .002), and diffusion restriction (P = .045) were significantly more frequent in group I than group II. The beak sign, bulging sign, and diffusion restriction were correlated with presence of MVI. Largest tumor size and multifocality were higher in group I than group II, but the differences were not statistically significant. CONCLUSION: Radiologists and transplant surgeons should be aware of some clue imaging findings, especially beak and bulging signs because these findings may predict the presence of MVI in HCC. These patients might benefit from histologic confirmation of the tumor characteristics through biopsy and subsequent bridging treatment options before liver transplantation to reduce the risk of recurrence.

Novel Application of Internal-External Drainage Catheter as Biliary Stent for Percutaneous Transhepatic Treatment of Biliary Strictures in Living Donor Liver Transplantation Recipient Patients.

OBJECTIVES: Although endoscopic management is considered as the first-line treatment for biliary strictures, it may be challenging in living donor liver transplant recipients due to the complex nature of duct-to-duct reconstruction. In this study we present the use of a pigtail drainage catheter as a biliary stent to treat biliary strictures after a living donor liver transplant. METHODS: Twenty-seven patients with biliary strictures were treated with our novel technique. In this technique, a pigtail catheter was trimmed into 3 parts (proximal, middle, and distal portions). A suture string was passed through the distal hole of the middle portion, which was then reversed and used as a stent while the proximal portion was used as a pusher. Following balloon dilation of the stenotic segment, the distal, reversed middle, and proximal portions were loaded over the guidewire. After proper placement of the stent, the retractor suture string, pusher, and guidewire were removed. The stent was removed during the third or fourth month of placement through endoscopic retrograde cholangiopancreatography (ERCP) in all patients. RESULTS: No significant complications developed during the procedure or follow-up period. Ten patients required re-stenting by ERCP during the same session. The mean follow-up period was 2 years. Cholestase enzymes and bilirubin levels were within normal limits in all patients during follow-up. CONCLUSION: Stents derived from drainage catheter facilitate treatment of biliary strictures in patients not eligible for the retrograde approach. This stent is cheap, easy to implement, can be easily removed by ERCP, and re-stenting can be applicable in retrograde if needed.

The relationship of spleen stiffness value measured by shear wave elastography with age, gender, and spleen size in healthy volunteers.

PURPOSE: The aim of this study is to evaluate spleen stiffness values with shear wave elastography (SWE) quantitatively in healthy adults and investigate the relationship of spleen stiffness with age, gender, and spleen size. METHODS: This study included 65 healthy individuals. Spleen stiffness measurement was obtained with 2 dimensional (2-D) SWE method from the middle portion of spleen and calculated in kilopascals by taking the average of three valid measurements. Longitudinal and transverse spleen sizes were measured. The relationship of spleen stiffness with age, gender, and spleen size was investigated. The association between spleen size and age and gender was also evaluated. RESULTS: The mean spleen stiffness value was 13.82 ± 2.91 kPa, and the spleen stiffness was not affected by age, gender, or spleen size. Longitudinal spleen size was significantly lower in females than that in males. Moreover, there was a significant negative correlation between longitudinal spleen size and age (r = 0.247, p = 0.048). CONCLUSION: Spleen stiffness can be quantitatively measured by 2-D SWE, and the spleen stiffness is not affected by age, gender, and spleen size. The values obtained in this study can be used as normal base values in examination of different spleen pathologies.

Diagnostic performances of intravoxel incoherent motion and conventional diffusion-weighted imaging in the differential diagnosis of benign and malignant portal vein thrombus.

PURPOSE: To evaluate the diagnostic accuracy of intravoxel incoherent motion (IVIM) and diffusion-weighted imaging (DWI) parameters in the differential diagnosis of portal vein thrombus (PVT). METHODOLOGY: Thirty-five patients with PVT were enrolled in this retrospective study. Precontrast axial in-phase and out-of-phase T1-weighted (W) turbo field echo (TFE), axial and coronal T2-W single-shot turbo spin echo, IVIM with b values between 0 and 1300 s/mm2 and conventional DWI with b factors of 50, 400, and 800 s/mm2 with single-shot echo-planar imaging, and postcontrast dynamic T1-W volumetric interpolated breath-hold examination images obtained with 1.5 T MR unit were evaluated. For quantitative analysis of conventional DWI, an ADC map was reconstructed from conventional DWI using all b values. For quantitative evaluation of IVIM, the SI was calculated from each b value. A specific software program was applied to calculate D (true diffusion coefficient), D* (pseudodiffusion coefficient associated with blood flow), and f (perfusion fraction). The differentiation between benign and malignant PVT was based on the criteria outlined in the study by Catalano et al. (Radiology 254:154-162, 2010). RESULTS: The ADC values of the malignant PVT were significantly lower than those of benign PVTs (p = 0.005). Malignant PVTs had a tendency to show higher f values in comparison with benign PVTs without statistical significance (p = 0.750). The best discriminative parameter was ADC values, which demonstrated a sensitivity of 80.0% and a specificity of 72.7% with cut-off value of 1.00 × 10-3 mm2/s. CONCLUSION: ADC values might be more superior tool than IVIM parameters in differentiation between malignant and benign PVT.

Is evaluation of placenta with real-time sonoelastography during the second trimester of pregnancy an effective method for the assessment of spontaneous preterm birth risk?

PURPOSE: The aim of this study is to investigate the effectiveness of placental strain ratio (SR) values measured by real-time sonoelastography (SE) in the second trimester in the prediction of spontaneous preterm birth (sPTB). METHODS: This study included 70 pregnant women who applied to our clinic for routine second-trimester screening. Placental SR measurements were performed with the SE method. Two different SR measurements were performed by taking two different tissues as references. The SR value measured when taking the rectus abdominis muscle as a reference was termed the muscle-to-placenta strain ratio (MPSR), while the SR value measured when taking subcutaneous tissue as a reference was termed the fat-to-placenta strain ratio (FPSR). Women whose gestational age at birth was less than 37 weeks 0 days were accepted as sPTB. The association between gestational age at birth and MPSR and FPSR was investigated. Receiver operating characteristics analysis was used to calculate the sensitivity and specificity of the elastographic outcomes. RESULTS: There was a low-level negative correlation between MPSR and gestational age at birth (r=-0.300, P=.012) and there was a moderate-level negative correlation between FPSR and gestational age at birth (r=-0.513, P<.001). The multivariate linear regression analysis showed that the FPSR (ß=0.609, P=.002) was the significant predictor for the sPTB. CONCLUSIONS: Our data indicate that the FPSR value measured with real-time SE in the second trimester of pregnancy may be effective in the prediction of sPTB.

Large-cell lung cancer originating from tracheal bronchus - A rare case.

Tracheal bronchus is a rarely seen congenital anomaly generally originating from the right lateral wall of the trachea and approximately 2 cm above the carina. It was firstly defined by Sandifort in 1785 and its frequency of incidence in normal population changes between 0.1% and 2%. There are two types called ''Supernumerary'' and ''Displaced''. It is a rarely seen kind of tracheal anomaly although fairly well defined. The cases accompanied by lung cancer are seen more rarely. Nine cases of this association were reported in literature and tracheal bronchus-lung cancer association whose pathological result is undifferentiated large-cell carcinoma has not been stated so far. We present a 75 years old male patient as possibly the first case having tracheal bronchus and large-cell carcinoma association in literature.