Nagihan Inan

Diffusion-Weighted Imaging in the Differential Diagnosis of Cystic Lesions of the Pancreas

OBJECTIVE The purpose of our study was to evaluate the value of diffusion-weighted imaging (DWI) in the differential diagnosis of pancreatic cysts. SUBJECTS AND METHODS Forty-two cysts (16 simple cysts, seven pseudocysts, five abscesses, three hydatid cysts, two serous cystadenomas, three mucinous cystadenomas, two mucinous cystadenocarcinomas, four cystic degenerated adenocarcinomas) were included in this prospective study. Single-shot spin-echo echo-planar DWI was performed with three b factors (0, 500, and 1,000 s/mm(2)), and apparent diffusion coefficients (ADCs) were calculated. On DWI, the signal intensity of the cysts was visually compared with the signal intensity of the pancreas parenchyma. For the quantitative evaluation, cyst-to-pancreas signal intensity ratios, ADC of the lesions, and cyst-to-pancreas ADC ratios were compared. RESULTS On visual evaluation, all cystic lesions were hyperintense on DWI with b factors of 0 and 500 s/mm(2). On DWI with a b factor of 1,000 s/mm(2), all abscesses and hydatid and neoplastic cysts were hyperintense, whereas most of the simple and pseudocysts were isointense. Quantitatively, with b factors of 0 and 500 s/mm(2), no statistical significance was achieved. With a b factor of 1,000 s/mm(2), the cyst-to-pancreas signal intensity ratios of the abscesses and hydatid and neoplastic cysts were significantly higher than those of the simple cysts and pseudocysts. Setting the cutoff value of signal intensity ratio at 1.9, the cyst-to-pancreas signal intensity ratio had a sensitivity of 70% and a specificity of 90% for differentiating abscesses, hydatid cysts, and neoplastic cysts from simple cysts and pseudocysts. The ADC and the ADC ratios of the abscesses, hydatid cysts, and neoplastic cysts were significantly lower than those of the simple cysts and pseudocysts. CONCLUSION DWI may help in the differential diagnosis of pancreatic cysts.

Diffusion-Weighted Imaging in the Differential Diagnosis of Simple and Hydatid Cysts of the Liver

OBJECTIVE The purpose of our study was to evaluate the value of diffusion-weighted imaging (DWI) in the differential diagnosis of simple and hydatid cysts of the liver, particularly in the completely liquid type of hydatid cyst. SUBJECTS AND METHODS Eighty-two cysts (43 simple cysts, 39 hydatid cysts) were included in this prospective study. DWI was performed using a breath-hold single-shot echo-planar spin-echo sequence, and apparent diffusion coefficients (ADCs) were calculated. On DW trace images, the signal intensity of cysts was visually compared with the signal intensity of the liver using a 3-point scale: 0, isointense; 1, moderately hyperintense; and 2, significantly hyperintense. Quantitatively, signal intensity of the cysts, cyst-to-liver signal intensity ratios, ADC of the cysts, and cyst-to-liver ADC ratios were compared between the groups. The statistical significance was determined using the Mann-Whitney U test. RESULTS On trace DWI (b = 1,000 s/mm2), most hydatid cysts (37/39, 95%) were hyperintense, whereas most simple cysts (40/43, 93%) were isointense with the liver. Three simple cysts (7%) were moderately hyperintense and two hydatid cysts (5%) were isointense. Quantitatively, both the signal intensity and cyst-to-liver signal intensity ratio of the hydatid cysts were significantly higher than those for simple cysts (p < 0.001). The cutoff value at 1.5 yielded a sensitivity of 77%, a specificity of 86%, and positive predictive value of 83% for the cyst-to-liver signal intensity ratio. The ADC and cyst-to-liver ADC ratio of the hydatid cysts were significantly lower than those of simple cysts (p < 0.005). For the completely liquid type in particular, we observed statistically significant differences in signal intensity, signal intensity ratio, ADC, and ADC ratios from those of simple cysts (p < 0.005). With a cutoff value of 1.5, signal intensity ratio had a sensitivity of 81%, specificity of 86%, and positive predictive value of 74%. CONCLUSION DWI may help in the differential diagnosis of hydatid and simple cysts of the liver.

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.

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

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/mm2 values. Apparent diffusion coefficient (ADC) maps were calculated by using images with b=0 and 1000 s/mm2 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/mm2 and p<0.000 for the other b values). Using b=500 s/mm2, SI≥391 indicated a malignant lesion with a sensitivity of 95%, specificity of 73% and positive predictive value of 87%. Using b=1000 s/mm2, 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/mm2 (p<0.04). Conclusions. Diffusion-weighteted MR trace image SI is useful for the differentiation of malignant versus benign lung lesions.

Hepatic Adenomatosis in a 7-Year-Old Child Treated Earlier With a Fontan Procedure

Patients who undergo a Fontan procedure experience some degree of liver disease. Hemodynamic changes such as central venous hypertension, depressed dynamic cardiac output, and late ventricular dysfunction combined with long-standing hypoxia preceding the Fontan procedure all are recognized risk factors for hepatic injury. The histopathologic changes associated with cardiac hepatopathy include chronic passive congestion, centrilobular necrosis, and cardiac cirrhosis. However, hepatic adenoma and hepatic adenomatosis (HA) are not well-known pathologies during the course of cardiac hepatopathy. This study focused on a 7-year-old girl with chronic hepatic changes and HA who had undergone a Fontan procedure. Hepatic adenomatosis was diagnosed on the basis of magnetic resonance imaging (MRI) and MRI-guided liver biopsy. To the best of the authors’ knowledge, this case involved the youngest patient with hepatocellular adenomatosis documented in the literature. It was a unique case because the patient experienced HA after a Fontan procedure.

RESPONSE TO RITUXIMAB AND PREDNISOLONE FOR OPSOCLONUS-MYOCLONUS-ATAXIA SYNDROME IN A CHILD WITH GANGLIONEUROBLASTOMA

Opsoclonus-myoclonus-ataxia (OMA) syndrome is a rare neurobehavioral paraneoplastic disorder in children with neuroblastic tumors. The neurologic symptoms are generally treated with a number of immunosupressive and immunomodulating agents. A 4-year-old previously healthy male patient was admitted to the authors’ center with progressive ataxia, gait disturbance, diffuculty of speech, and opsoclonus. He had a diagnosis of ganglionueroblastoma at the thoracal paraspinal region. Following surgey, the patient received IVIG and prednisolone but his cerebellar symptoms progressed. Rituximab therapy was started and continued for total 8 weeks without any side effect. The authors observed excellent neurologic response in the patient at the 4th week of treatment. Rituximab is a new, promising, and safe therapy for OMA syndrome in children with neuroblastoma.

Gorham-Stout Syndrome with Chylothorax in a Six-Year-Old Boy

Gorham-Stout syndrome, also called “disappearing bone disease, diffuse cystic angiomatosis of bone, disseminated lymphangiomatosis, Gorham’s vanishing bone disease, phantom bone disease or idiopathic massive osteolysis, is a rare disease of unknown etiology and pathogenesis. It is characterized by rapidly progressive localized massive osteolysis associated with proliferation of vascular structures of benign origin in which the absence of new bone formation is representative. When it is complicated by chylothorax, the prognosis is poor. The authors report a 6-year-old boy with Gorham-Stout syndrome who presented with pleural effusion showing features of chylothorax, who responsed poorly to currently available therapeutic modalities.

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

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/mm2), 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 students-t test. Results. With the b factor 500 sec/mm2, no statistical significance was achieved (p>0.05). With the b factor of 1000 sec/mm2, 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.

Popliteus muscle sesamoid bone (cyamella): appearance on radiographs, CT and MRI

Popliteus muscle sesamoid bone, also known as cyamella, is an accessory ossicle that is located in the vicinity of the proximal musculo tendinous junction. While commonly seen in small mammals such as cats and dogs, its presence in humans is very rare. In this report, we present the radiological findings of the popliteus muscle sesamoid bone, incidentally detected in a 47-year-old male. CT and MRI features of this ossicle are described.

Gender and the lateral angle of the internal acoustic canal meatus as measured on computerized tomography of the temporal bone

INTRODUCTION Cadaveric studies yielded promising results in sexing the temporal bones by measuring the lateral angle of the internal acoustic canal meatus. In this study, we evaluated the capability of computerized tomography of the temporal bone to reproduce these results. METHODS Lateral angle of the internal acoustic canal meatus was measured in 92 patients (47 females and 45 males) on axial slices of high resolution computerized tomography scans of the temporal bone. The patients underwent computerized tomography as part of clinical work up for ear-related complaints. The measurement technique was modified from a cadaveric study in which a significantly higher mean lateral angle measurement was observed in females than in males. The mean values from females and males were compared statistically. RESULTS The mean lateral angle as measured on computerized tomography of the temporal bone is greater in females (45.5+/-7.1 degrees ) than in males (41.6+/-6.7 degrees ). The difference is significant at p<0.01, as tested by one-way ANOVA. Due to significant overlap in ranges of measurements, no single cut-off value that satisfactorily differentiates between the genders could be determined. However, measurements of 35 degrees and lesser were 93.6% specific for male gender and measurements of 60 degrees and greater were 97.7% specific for female gender. CONCLUSION Computerized tomography of the temporal bone is capable of replicating the results from the cadaveric measurements in determining the lateral angle. Due to the large range of measurements within both genders, this measurement should be regarded as supportive and not conclusive evidence for the sex of the subject.