Ovarian tumors are classified on the basis of tumor origin as epithelial tumors (serous and mucinous tumors, endometrioid and clear cell carcinomas, Brenner tumor), germ cell tumors (mature and immature teratomas, dysgerminoma, endodermal sinus tumor, embryonal carcinoma), sex cord-stromal tumors (fibrothecoma; granulosa cell, sclerosing stromal, and Sertoli-Leydig cell tumors), and metastatic tumors. Epithelial tumors are primarily cystic and, when malignant, are associated with varying proportions of a solid component. Papillary projections are a distinctive feature of epithelial tumors. Profuse papillary projections are highly suggestive of borderline (low-malignant-potential) or malignant tumor. Ovarian teratomas demonstrate lipid material at computed tomography and magnetic resonance (MR) imaging. Malignant germ cell tumors manifest as a large, complex abdominal mass that contains both solid and cystic components. Tumor markers are helpful in diagnosis. The radiologic appearance of sex cord-stromal tumors varies from small solid masses to large multicystic masses. Granulosa cell tumors are usually large multicystic masses with solid components. Fibrothecoma, sclerosing stromal tumor, and Sertoli-Leydig cell tumors are usually solid masses. Fibromas have very low signal intensity on T2-weighted MR images. Certain radiologic findings predominate for each type of tumor. Knowledge of these key features of ovarian tumors provides the criteria for making a specific diagnosis or substantially narrowing the differential diagnosis.

Clinical and radiologic clues are helpful in differential diagnosis from the more common epithelial tumors; sex cord-stromal tumors primarily are treated surgically and have generally good prognosis.

The tracheal tumors were eccentric, well-defined, polypoid masses in all cases. The endobronchial tumors were masses confined within the bronchus in all cases, and atelectasis or pneumonia of the distal parenchyma was frequently associated. Of the six hamartomas, one was a fatty mass, and two were nodules with calcification. The others were soft-tissue-density nodules. The lipomas manifested as fat density on CT scans in both cases. The other benign tumors were low-attenuating, soft-tissue-density masses without characteristic findings on CT scans.

Typically, reversible posterior leukoencephalopathy syndrome (RPLS) involves the parieto-occipital lobes. When regions of the brain other than the parieto-occipital lobes are predominantly involved, the syndrome can be called atypical RPLS. The purpose of this study is to find radiological and pathophysiological features of atypical RPLS by using diffusion-weighted imaging (D-WI). We retrospectively reviewed seven patients (two with eclampsia, one with cyclosporine neurotoxicity, and four with hypertensive encephalopathy) with atypical MR manifestations of RPLS. Changes in signal intensity on T2-weighted imaging (T2-WI) and D-WI, and ADC ratio, were analyzed. In patients with atypical manifestation of RPLS, high signal intensities on T2-WI were noted in the frontal lobe, basal ganglia, thalamus, brainstem, and subcortical white matter in regions other than the parieto-occipital lobes. These areas of increased signal intensities on T2-WI showed increased ADC values, representing vasogenic edema in all seven patients. This result should be very useful in differentiating atypical RPLS from other metabolic brain disorders that affect the same sites with cytotoxic edema.

CT and MRI are utilized to differentiate between different types of masses and to determine the extent of lesions involving the lacrimal gland and the fossa. Although many diseases that affect the lacrimal gland and fossa are specifically diagnosed by imaging, it is frequently very difficult to differentiate each specific disease on the basis of image characteristics alone due to intrinsic similarities. In lacrimal gland epithelial tumors, benign pleomorphic adenomas are seen most commonly with a well defined benign appearance, and a malignant adenoid cystic carcinoma is seen with a typical invasive malignant appearance. However, a malignant myoepithelial carcinoma is seen with a benign looking appearance. Lymphomatous lesions of the lacrimal gland include a broad spectrum ranging from reactive hyperplasia to malignant lymphoma. These lesions can be very difficult to differentiate both radiologically and pathologically. Generally, lymphomas tend to occur in older patients. The developmental cystic lesions found in the lacrimal fossa such as dermoid and epidermoid cysts can be diagnosed when the cyst involves the superior temporal quadrant of the orbit and manifests as a non-enhancing cystic mass and, in case of a lipoma, it is diagnosed as a total fatty mass. However, masses of granulocytic sarcoma and xanthogranuloma, as well as vascular masses, such as a hemangiopericytoma, are difficult to diagnose correctly on the basis of preoperative imaging findings alone. A careful clinical evaluation and moreover, a pathologic verification, are needed. In this pictorial review, the various imaging spectrums of pathologic masses involving the lacrimal gland and fossa are presented, along with appropriate anatomy and pathology reviews.

The MR characteristics of successfully ablated breast cancers included central dark signal intensities with thin rim enhancement on subtraction images. Nodular or irregular thick enhancements should raise concern of partial ablation. We propose MRI plays a critical role in assessing the effectiveness of HIFU treatment.

Breast cancer is the second most common cause of cancer-related death in women. In most patients, imaging demonstrates thoracic changes resulting from either treatment, complications of treatment, or tumor recurrence or metastasis. The postsurgical imaging appearance of the chest wall depends on the surgical method used (radical mastectomy, modified radical mastectomy, breast-conserving surgery, breast reconstruction). The most common surgery-related complication is seroma. Radiation therapy frequently causes radiation pneumonitis, which occurs approximately 4-12 weeks after the completion of therapy and is characteristically limited to the field of irradiation. Chemotherapy-related complications include cardiotoxicity, pneumonitis, and infection. Ultrasonography and computed tomography are more sensitive than physical examination for detecting local and regional recurrence. The thorax is a common site of metastasis, which may affect the lymph nodes, bone, lung, pleura, or heart and pericardium. Bone metastasis is usually evaluated with bone scintigraphy and may cause spinal cord compression, a serious complication that requires early diagnosis. Intrapulmonary metastasis may manifest as single or multiple pulmonary nodules, airspace pattern metastasis, lymphangitic metastasis, or endobronchial metastasis. Pleural metastasis usually manifests as pleural effusion, with or without a pleural mass. Familiarity with the spectrum of radiologic findings in breast cancer patients allows accurate image interpretation and correct diagnosis.

The aim of this study was to correlate MR findings of gallbladder wall thickening with pathologic findings on the basis of the layered pattern and to evaluate the diagnostic value of MR imaging in gallbladder disease. We retrospectively evaluated the source images of HASTE sequences for MR cholangiography in 144 patients with gallbladder wall thickening. The layered pattern of thickened wall was classified into four patterns. Type 1 shows two layers with a thin hypointense inner layer and thick hyperintense outer layer. Type 2 has two layers of ill-defined margin. Type 3 shows multiple hyperintense cystic spaces in the wall. Type 4 shows diffuse nodular thickening without layering. MR findings of a layered pattern of thickened gallbladder were well correlated with histopathology. Chronic cholecystitis matched to type 1, acute cholecystitis corresponded to type 2, adenomyomatosis showed type 3, and the gallbladder carcinomas showed type 4. All four layered patterns were associated with PPV of 73% or greater, sensitivity of 92% or greater and specificity of 95% or greater. Our results indicate that MR findings of gallbladder wall thickening are characteristic in each entity and correlate well with pathologic findings. The classification of the layered pattern may be valuable for interpreting thickened gallbladder wall.