Correlation of the measurements of optical coherence tomography and diffuse tension imaging of optic pathways in amblyopia.

The aim of this study was to investigate whether a correlation exists between optical coherence tomography (OCT) of retina and diffusion tensor imaging (DTI) of the optic pathway measurements. All subjects underwent OCT measurements of optic nerve head, retinal nerve fiber layer, and macula. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of optic pathways were analyzed using DTI. Prechiasmatic FA values were significantly decreased in unilateral amblyopic group in both affected and sound fellow eyes (p = 0.019 and 0.013), but not in bilateral amblyopic group (p = 0.221) when compared with the control group. ADC values were significantly greater in sound eye in unilateral amblyopic group in prechiasmatic and postchiasmatic regions (p = 0.001 and 0.049). ADC values were also significantly greater in bilateral amblyopic group in postchiasmatic region (p = 0.037). There were no significant differences between the affected eye and sound eye side DTI measurements. There was no significant correlation between prechiasmatic DTI and OCT measurements in affected and sound eyes of unilateral amblyopia group. DTI results demonstrated that there is a functional underdevelopment of the anterior and posterior visual pathways in both affected and sound eye of unilateral amblyopic patients. Significantly reduced FA values in prechiasmatic region where OCT values of retina were normal can be explained by possible micro-structural changes.

High-resolution computed tomography and rheumatoid arthritis: semi-quantitative evaluation of lung damage and its correlation with clinical and functional abnormalities.

BACKGROUND: We aimed to establish risk factors for radiological lung damage associated with rheumatoid arthritis (RA) and determine whether clinical findings and pulmonary function test were correlated with Warrick score calculated on the basis of high-resolution computed tomography or not. METHODS: One hundred thirty RA patients who were followed at rheumatology outpatient clinic were included through retrospective screening. To evaluate radiological involvement, the semi-quantitative evaluation proposed by Warrick was used to assign a score for each lesion based on the severity and extent of the pulmonary damage. In addition to the total score, indices for alveolitis and fibrosis were created. The correlations between each score and clinical and functional parameters were tested for all patients. RESULTS: We showed that age was an independent explanatory variable of radiological lung damage. Percentage of predicted lung diffusion capacity for carbon monoxide (DLco) below 75 % and presence of respiratory symptoms were found to contribute more to radiological lung damage. Warrick score was positively correlated with age at study onset (r = 0.43, p < 0.001). In addition, a negative correlation was found between Warrick score and DLco % predicted (r = -0.357, p = 0.001). Alveolitis index was negatively correlated with DLco % predicted (r = -0.321, p = 0.003). CONCLUSIONS: It is considered that this semi-quantitative method may have added value in early diagnosis, appropriate treatment decisions and follow-up when taken into account together with risk factors associated with pulmonary damage in RA.

Concomitant Persistent Atelectasis following TEVAR Due to a Descending Aortic Aneurysm: Hybrid Endovascular Repair and ECMO Therapy.

Many thoracic aortic aneurysms are discovered incidentally, and most develop without symptoms. Symptoms are usually due to sudden expansion of the aneurysm, which can cause a vague pain in the back, or sometimes a sharp pain that may denote the presence of impending rupture. Other symptoms are related to pressure on adjacent structures, such as pressure on the bronchus that can cause respiratory distress, or pressure on the laryngeal nerve causing vocal hoarseness. Pressure on the esophagus can cause difficulty in swallowing. Currently, open surgery and thoracic endovascular aneurysm repair (TEVAR) are the choices of treatment for descending thoracic aneurysms (DTA). The decision to intervene on a DTA depends on its size, location, rate of growth and symptoms, and the overall medical condition of the patient. The indications for TEVAR should not differ from those for open surgery and typically include aneurysms larger than 6 cm in diameter. Saccular and symptomatic aneurysms are often repaired at a smaller size. It is also suggested that aneurysms with a growth rate more than 1 cm per year, or 0.5 cm in 6 months should be considered for early repair.Despite the close proximity of the aorta and left main bronchus, atelectasis caused by thoracic aortic aneurysms is rare. We review the case report of a patient with concomitant persistent left pulmonary atelectasis causing acute respiratory distress due to complete compression of the left main bronchus after TEVAR of a descending thoracic aortic aneurysm.

Preoperative evaluation of myometrial invasion in endometrial carcinoma: diagnostic performance of 3T MRI.

PURPOSE: To evaluate the diagnostic accuracy of 3T MRI in preoperative staging of myometrial invasion. METHODS: Twenty-eight women with histological diagnosis of endometrial carcinoma were included in this prospective study. After T2-W SS-TSE and DWI, dynamic series of T1-W THRIVE images were obtained (0-180 s) followed by a T1-W THRIVE sequence in the late phase (5th min). For detection of deep myometrial infiltration: sensitivity, specificity, PPV, NPV, and accuracy were calculated on T2-W, postcontrast early arterial and late phase T1-W, and DWI. For the quantitative analysis of DWI, ADC values of the tumor were calculated and correlated with histologic grade. For the quantitative evaluation of dynamic series, SI-time curves were obtained and the maximum relative enhancement, wash-in rate, time-to-peak, and wash-out rate of masses and myometrium were compared. RESULTS: T2-W and early phase contrast-enhanced sequences obtained sensitivity 100 %, specificity 76 %, PPV 58 %, NPV 100 %, and accuracy 82 %; late-phase contrast-enhanced images obtained sensitivity 100 %, specificity 81 %, PPV 64 %, NPV 100 %, and accuracy 86 %; DWI obtained lower accuracy [sensitivity 71 %, specificity 62 %, PPV 38 %, NPV 87 %, and accuary 57 %] than T2-W and postcontrast images. The MRE of carcinomas were significantly lower than those of the myometrium. This analysis showed a significant improvement in tumor versus myometrium contrast during the late phase. On DWI, the mean ADC value of tumor was 1.02 ± 0.48 × 10(-3). There was no statistically significant correlation between tumor grades and ADCs. CONCLUSIONS: As the 3T MRI scanner allows high-resolution images, accurate assessment of myometrial infiltration can be done especially with postcontrast late phase images.

Malignant versus benign mediastinal lesions: quantitative assessment with diffusion weighted MR imaging.

OBJECTIVES: We aimed to evaluate the performance of diffusion-weighted magnetic resonance imaging in differentiating malignant from benign mediastinal lesions. METHODS: Fifty-three mediastinal lesions were examined with T1- and T2-weighted (W) conventional images. Then, two diffusion-weighted images were obtained with b = 0 and 1000 s/mm² values and apparent diffusion coefficients (ADC) were calculated. The statistical significance of differences between measurements was tested using the Student-t test. RESULTS: The mean ADC of malignant lesions was significantly lower than that of the benign masses (p < 0.001). The cut-off value of ≤ 1.39 × 10(-3) mm²/s indicated a malignant lesion with a sensitivity of 95% and specificity of 87%. CONCLUSION: Diffusion-weighted imaging may be helpful in differentiating benign from malignant mediastinal masses.

Renal artery aneurysm in a hypertensive child treated by percutaneous coil embolization.

A 16-year-old boy was admitted to our hospital with uncontrolled hypertension. A left renal artery aneurysm was detected on colour Doppler US and CT. Renal arteriography demonstrated the aneurysm and focal renal parenchymal areas of decreased perfusion. The renal artery aneurysm was successfully treated by transcatheter coil embolization.

Diffusion weighted MR imaging in the differential diagnosis of haemangiomas and metastases of the liver.

BACKGROUND: The purpose of the study was to evaluate the value of diffusion-weighted imaging in the differential diagnosis of haemangiomas from metastases of the liver. PATIENTS AND METHODS.: We analyzed 69 lesions in 38 patients (33 haemangiomas; 36 metastases) in the retrospective study. Diffusion-weighted imaging was performed using a breath-hold single-shot echo-planar spin echo sequence with three b factors (0, 500 and 1000 sec/mm(2)), and apparent diffusion coefficients (ADCs) were calculated. For the quantitative evaluation, signal intensity of the lesions, lesion-to-liver signal intensity ratios, ADC of the lesions, and lesion-to-liver ADC ratios were compared between the groups. The statistical significance was determined by student's-t test. RESULTS: With the b factor 500 sec/mm(2), no statistical significance was achieved (p>0.05). With the b factor of 1000 sec/mm(2), both the signal intensity and lesion-to-liver signal intensity ratio of the metastases were significantly higher than those for haemangiomas (p<0.001). The cut-off value at 2.6 yielded a sensitivity of 86% and a specificity of 82% for the lesion-to-liver signal intensity ratio. The ADC, and lesion-to-liver ADC ratio of the metastases were significantly lower than those of haemangiomas (p<0.001). With cut-off value of 1.7, ADC ratio had a sensitivity of 88% and a specificity of 72% for ADC lesion/liver. CONCLUSIONS: Diffusion-weighted imaging with high b value may help in the differential diagnosis of metastases from haemangiomas of the liver.

Detection and Evaluation of Intracranial Aneurysms with 3D-CT Angiography and Compatibility of Simulation View with Surgical Observation.

AIM: The aim of this study was to report our experience with a 64-channel computerized tomography (CT) scanner as the primary choice on the detection of intracranial aneurysms. Comparison of intracranial aneurysms with the simulated images obtained via three-dimensional computed tomography angiography (3D-CTA) in pterional approach was also aimed. MATERIAL AND METHODS: Among 288 consecutive patients who had intracranial aneurysms detected on 64-slice CTA, a total of 337 aneurysms were detected. CTA simulation images and intraoperative images were compared with regards to size, shape, and orientation. RESULTS: In one of the 22 CTA-negative cases, one aneurysm was detected in DSA and an additional aneurysm was detected in a patient operated with CTA. Aneurysm size, shape and direction were error free except a few cases. However, CTA was found to be insufficient to show particularly perforating arteries that were smaller than 2 mm in size. CONCLUSION: As a fast and noninvasive technique, CTA can be used as an initial examination in subarachnoid hemorrhage. Keeping the fact that there can be insufficiency in showing particularly small aneurysms in mind, DSA should be performed on CTA-negative cases and required cases.

Diagnostic performance of conventional diffusion weighted imaging and diffusion tensor imaging for the liver fibrosis and inflammation.

OBJECTIVE: To evaluate the diagnostic accuracy of liver apparent diffusion coefficient (ADC) measured with conventional diffusion-weighted imaging (CDI) and diffusion tensor imaging (DTI) for the diagnosis of liver fibrosis and inflammation. MATERIALS AND METHODS: Thirty-seven patients with histologic diagnosis of chronic viral hepatitis and 34 healthy volunteers were included in this prospective study. All patients and healthy volunteers were examined by 3T MRI. CDI and DTI were performed using a breath-hold single-shot echo-planar spin echo sequence with b factors of 0 and 1000 s/mm(2). ADCs were obtained with CDI and DTI. Histopathologically, fibrosis of the liver parenchyma was classified with the use of a 5-point scale (0-4) and inflammation was classified with use of a 4-point scale (0-3) in accordance with the METAVIR score. Quantitatively, signal intensity and the ADCs of the liver parenchyma were compared between patients stratified by fibrosis stage and inflammation grade. RESULTS: With a b factor of 1000 s/mm(2), the signal intensity of the cirrhotic livers was significantly higher than those of the normal volunteers. In addition, ADCs reconstructed from CDI and DTI of the patients were significantly lower than those of the normal volunteers. Liver ADC values inversely correlated with fibrosis and inflammation but there was only statistically significant for inflammatory grading. CDI performed better than DTI for the diagnosis of fibrosis and inflammation. CONCLUSION: ADC values measured with CDI and DTI may help in the detection of liver fibrosis. They may also give contributory to the inflammatory grading, particularly in distinguishing high from low grade.

Comparison of the diagnostic performances of diffusion parameters in diffusion weighted imaging and diffusion tensor imaging of breast lesions.

PURPOSE: To evaluate the diagnostic efficiency of the diffusion parameters measured by conventional diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) for discrimination of malignant breast lesions from benign lesions and the normal breast. MATERIALS AND METHODS: The study included 52 women with 55 breast lesions (30 malignant, 25 benign). DTI and DWI were performed complementary to dynamic contrast MRI at 3T. Apparent diffusion coefficient (ADC) of DWI, mean diffusivity (MD) and fractional anisotropy (FA) values of DTI were measured for lesions and contralateral breast parenchyma in each patient. We used b factors of 0, 50, 850, 1000 and 1500 s/mm(2) for DWI and b 0 and 1000 s/mm(2) for DTI. ADC, MD and FA values were compared between malignant and benign lesions, and the normal parenchyma by univariate and multivariate analyses. RESULTS: Diffusion parameters showed no difference according to menopausal status in the normal breast. ADC and MD values of the malignant lesions were significantly lower than benign lesions and normal parenchyma (p=0.001). The FA showed no statistical significance. With the cut-off values of ≤ 1.23 × 10(-3)mm(2)/s (b 0-1000 s/mm(2)) and ≤ 1.12 × 10(-3)mm(2)/s (b 0-1500 s/mm(2)), ADC showed 92.85% and 96.15% sensitivity; 72.22% and 73.52% PPV, respectively. With a cut-off value of ≤ 1.27 × 10(-3)mm(2)/s (b 1000 s/mm(2)), MD was 100% sensitive with a PPV of 65.90%. Comparing the diagnostic performance of the parameters in DTI with DWI, we obtained similar efficiency of ADC with b values of 0,1000 and 0,1500 s/mm(2) and MD with a b value of 0, 1000 s/mm(2) (AUC = 0.82 ± 0.07). CONCLUSION: ADC of DWI and MD of DTI values provide significant discriminative factors for benign and malignant breast lesions. FA measurement was not discriminative. Supported with clinical and dynamic contrast MRI findings, DWI and DTI findings provide significant contribution to the final radiologic decision.

Characterization of malignant thrombus in an invasive thymoma with intravascular growth.

We report an unusual case of an invasive thymoma with a thrombus in the right atrium and describe the radiological findings consistent with the malignant nature of the thrombus. The thrombus showed significant enhancement on computerized tomography images similar to the tumoral mass. On magnetic resonance imaging, both the tumor and the thrombus have heterogeneously high signal intensities on T2-weighted images. On diffusion-weighted images they both exhibit high signal intensity and low apparent diffusion coefficient (ADC) values which support the malignant nature of the thrombus and the mass.

Anterior visual pathways in amblyopia: quantitative assessment with diffusion tensor imaging.

PURPOSE: To detect the abnormalities of the anterior visual pathways in children with amblyopia with diffusion tensor imaging. METHODS: Ten children with unilateral amblyopia, 5 children with bilateral amblyopia, and 10 control children were treated using diffusion tensor imaging scanning in this institutional practice. Fractional anisotropy and mean diffusivity values were analyzed using diffusion tensor imaging in the prechiasmatic and chiasmatic regions. Fractional anisotropy and mean diffusivity values of the amblyopic groups were compared with the values of the control group using the Kruskal­Wallis test. The Mann­Whitney U test was used to evaluate pairwise differences between groups. RESULTS: When compared with the control group, prechiasmatic fractional anisotropy values were significantly decreased in both affected and sound fellow eyes in the unilateral amblyopic group (P = .019 and .013), but not in the bilateral amblyopic group (P = .221). Mean diffusivity values were significantly greater in the sound fellow eye in the unilateral amblyopic group in the prechiasmatic region (P = .001 and .049). CONCLUSION: Diffusion tensor imaging showed a significant decrease in fractional anisotropy and an increase in mean diffusivity values in the unilateral amblyopic group in both affected and sound fellow eyes. These findings may reflect axonal underdevelopment in anterior pathways, particularly in the unilateral amblyopic group.

A minimal invasive surgical alternative to aberrant systemic arterial supply: Coil embolization.

We present the case of a 20-year-old man with hemoptysis for 3 years. Chest radiography revealed increased pulmonary vascular opacities in the left lower lung field. Computed tomography showed an anomalous systemic artery arising from descending aorta supplying the basal segments of the left lower lobe. Bronchial tree was normal. Pulmonary artery angiogram revealed a hypoplastic inferior lobar branch of the left pulmonary artery. There was no direct communication between anomalous artery and pulmonary veins. We diagnosed our case as aortopulmonary collateral with normal lung parenchyma. Coil embolization of the anomalous systemic artery was performed. The patient survived well without evidence of hemoptysis for 18 months after coil embolization.

Differentiation of malignant and benign lung lesions with diffusion-weighted MR imaging.

BACKGROUND: The aim of the study was to evaluate the role of diffusion-weighted magnetic resonance imaging in the differential diagnosis of lung lesions. PATIENTS AND METHODS.: Sixty-seven patients with lung lesions (48 malignant, 19 benign) were included in this prospective study. Signal intensities (SIs) were measured in diffusion-weighted MR images that were obtained with b=0, 500 and 1000 s/mm(2) values. Apparent diffusion coefficient (ADC) maps were calculated by using images with b=0 and 1000 s/mm(2) values. The statistical significance was determined using the Student-t test. RESULTS: The SIs of malignant lesions were significantly higher than those of benign lesions (p<0.004 for b=0 s/mm(2) and p<0.000 for the other b values). Using b=500 s/mm(2), SI≥391 indicated a malignant lesion with a sensitivity of 95%, specificity of 73% and positive predictive value of 87%. Using b=1000 s/mm(2), SI≥277 indicated a malignant lesion with a sensitivity of 93%, specificity of 69% and positive predictive value of 85%. There was no significant difference between malignant and benign lesions regarding ADC values (p=0.675). There was no significant difference in SIs or ADC values between small cell carcinoma and non-small cell carcinoma. When comparing undifferentiated with well- partially differentiated cancers, SIs were higher with all b values, but the difference was statistically significant only with b=1000 s/mm(2) (p<0.04). CONCLUSIONS: Diffusion-weighteted MR trace image SI is useful for the differentiation of malignant versus benign lung lesions.

Early and delayed CT findings in patients with mild-to-moderate head trauma.

AIM: The aim of this study is to evaluate the changes between the initial and late cranial CT scans in patients with mild-to-moderate head trauma. MATERIAL and METHODS: Of the two thousand six hundred and forty-four patients hospitalized for head trauma within a two-year period, 112 (4.24%) patients scored 8 or above in the Glasgow coma scale and there were changes between initial and late head CT. RESULTS: Of these, 103 had worsening CT findings. Neurological status deteriorated in 30% of these cases. Forty-six patients required surgery based on findings seen on the delayed scans. Neurological status was stable in 50% of the cases. All the eight patients who expired had abnormal CT scans initially and had progression in their late scans. CONCLUSION: In patients with mild-to-moderate head trauma, serial CT scanning may independently modify treatment decisions in a subgroup of patients. Judgment for delayed scans should be made on an individual basis by taking the risk factors into account.