Mustafa Harman

Imaging of Renal Solid Tumors: Renal Cell Carcinoma and Others - Türk Radyoloji Seminerleri

Purpose To compare three chemical shift MRI techniques [two-dimensional (2D) dual gradient echo (dGRE), 3D VIBE, and 3D VIBE-Dixon] at 3 T and 2D dGRE technique at 1.5 T to assess their ability of detecting microscopic fat in adrenal adenomas and differentiating between adenomas and non-adenomas. Methods Seventy-eight patients with 97 lesions (78 adenomas, 19 non-adenomas) underwent both 1.5 T and 3 T chemical shift MRI. The Wilcoxon signed-ranked test was used to determine if there was significant difference between the signal intensity index (SII) values of each technique to assess their ability to detect microscopic fat in adrenal adenomas. ROC analysis was performed for the SII values of each technique, the adrenal-to-spleen SI ratio of 2D dGRE technique at 3 T, and the fat fraction values of the 3D VIBE-Dixon technique to identify the optimal threshold for differentiation of adrenal adenomas from non-adenomas. Results For detection of microscopic fat, the mean SII value of 2D dGRE technique at 1.5 T was significantly higher than that of the chemical shift imaging techniques at 3 T (p = 0.001). For discrimination of adenomas from non-adenomas, the area under the curve (AUC) and 95% confidence interval values of 2D dGRE technique at 1.5 T and 2D dGRE, 3D VIBE, 3D VIBE-Dixon techniques at 3 T were calculated as 1.00 (1.00–1.00), 0.991 (0.978–1.00), 0.999 (0.995–1.00), 0.993 (0.979–1.00), respectively, for the SII. Conclusion Chemical shift MRI at 1.5 T using the 2D dGRE technique provided the most accurate differentiation between adenomas and non-adenomas. However, there was no statistically significant difference between chemical shift imaging techniques at 1.5 T and 3 T.

With the exception of hemangioma, benign or malignant primary mesenchymal tumors of the liver are seldom encountered. The aim of this review was to discuss the clinical, histopathological, and imaging features of liver hemangiomas (cavernous, capillary, and sclerosed types), liver lipoma, angiomyolipoma, mesenchymal hamartoma, neurofibroma, infantile hemangioendothelioma, epithelioid hemangioendothelioma, myofibroblastoma, angiosarcoma, malignant fibrous histiocytoma, undifferentiated embryonal sarcoma, and nested stromal tumor. In most of these rare liver tumors, radiological findings obtained by cross-sectional imaging may reflect the characteristic pathologic features required for differential diagnosis; however, definitive diagnosis should be confirmed using histopathological examination.

Purpose: To assess the magnetic resonance imaging (MRI) signal and contrast-enhancement features of uterine fibroids before and after embolization, and to determine whether or not there are pre-embolization MRI characteristics that predict the volume reduction of fibroids. Material and Methods: Uterine fibroid embolization (UFE) was carried out in 28 fibroids of 20 patients, all of whom were symptomatic. The patients were prospectively evaluated with T1-weighted, T2-weighted, and gadolinium-enhanced T1 MRI sequences before and 6 months after embolization. The relationship between the characteristics of MRI signal and contrast-enhancement features of fibroids before the procedure and the change in size of the lesions after treatment was investigated. Results: Before embolization, the mean volume of fibroids was 123 cm³ (8–560 cm³). The decrease rate in fibroid volumes was 44.6% (range 7–70%) 6 months after embolization. Volume reduction was more prominent in fibroids that had a high signal intensity on T2-weighted images and a marked contrast enhancement on T1-weighted images ( P<0.001). However, the volume reduction was insufficient in fibroids with high signal characteristics on pre-contrast T1-weighted images ( P<0.001). Conclusion: MRI is an effective method for revealing size and signal changes of fibroids after embolization. MRI signal characteristics and the contrast-enhancement pattern of fibroids before embolization can predict tumor volume reduction after embolization.

We report ultrasound‐guided direct percutaneous injection of n‐butyl cyanoacrylate for preoperative embolization of carotid body tumor in a 50‐year‐old patient. Angiographic road map assistance was used for protection of parent arteries during the injection. After embolization, complete devascularization of the tumor was achieved without complications. The tumor was removed surgically with minimal blood loss. This procedure is effective and promising for preoperative embolization of carotid body tumors.

Contrast enhancement patterns of parathyroid adenomas in the arterial and venous phases were evaluated with multidetector computed tomography and specificity of the method to characterize the lesions was investigated. Arterial and venous enhancement patterns of parathyroid adenomas were evaluated retrospectively with multidetector computed tomography in 12 patients. All adenomas were removed surgically and the diagnosis was confirmed histopathologically. An area from the mandibular angle to the aortic arch was scanned with 1.5 mm section thickness in the arterial phase (20 seconds delay time) and venous phase (70 seconds delay time) after bolus injection of 50 ml of iodinated contrast media. Arterial and venous contrast enhancement of parathyroid adenomas was evaluated in the axial and coronal reformat images. Ten (83.3%) of 12 parathyroid adenomas showed a heterogeneous enhancement with a hypodense small central area in the arterial phase and a homogeneous enhancement in the venous phase. However, two small lesions, four and five mm in diameter respectively, showed homogeneous contrast enhancement in the arterial phase unlike the larger lesions which displayed a hypodense center in this phase. Dynamic scanning with multidetector computed tomography after contrast administration may be helpful in characterizing parathyroid adenomas.

A ten-year-old girl arrived at the hospital with progressive loss of muscular strength on the right side of the body. The cranial MRI showed left fronto-parietal ischemia and atrophic changes in the left parietal lobe. Brain MRI initially disclosed a narrow left MCA. MRA and digital angiography confirmed the diagnosis of brain obstructive chronic vascular disease (Moyamoya). Angiography results demonstrated occlusion of the left MCA and right posterior cerebral artery, with Moyamoya vessels. It therefore appears that in some patients Moyamoya disease is accompanied by posterior circulation involvement.