Takahiko Nakazono

MRI findings of mediastinal neurogenic tumors.

OBJECTIVE The objective of this article is to review the clinical, pathologic, and MRI findings of mediastinal neurogenic tumors according to the three tumor origins: the peripheral nerves, sympathetic ganglia, and paraganglia. CONCLUSION MRI findings reflect pathologic features of mediastinal neurogenic tumors. Integrating consideration of age and clinical findings of the patient, lesion location, and imaging findings is important in the diagnosis of mediastinal neurogenic tumors.

Intratumoral heterogeneity of the distribution of kinetic parameters in breast cancer: comparison based on the molecular subtypes of invasive breast cancer.

PurposeTo evaluate the distribution pattern of kinetic parameters in breast cancers with various molecular subtypes.Materials and methodsThis study was approved by institutional review board and was compliant with HIPAA. We classified 192 invasive breast cancers of 186 patients into four molecular subtypes using hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) results and evaluated the distribution pattern of kinetic parameters (percent volume of kinetic types relative to the tumor volume) in the molecular subtypes.ResultsIn the delayed phase, all three types of kinetic parameter (persistent, plateau, and washout pattern) were observed in each molecular subtype without any dominant type of kinetic parameter. The percentages of washout pattern in the HR+ and HER2− type and triple negative (TN) cancers tended to be lower than those in the other molecular subtype cancers.ConclusionEach molecular subtype of invasive breast cancer showed a heterogeneous kinetic pattern in dynamic-contrast magnetic resonance imaging (MRI). The HR+/HER2− cancers and the TN cancers had relatively lower percentages of washout pattern. When a manual assessment of the kinetic parameters is performed, close attention should be paid in order to identify the malignant washout kinetic pattern, particularly in HR+/HER2− cancer and TN cancer.

Diffusion weighted images of metastatic as compared with nonmetastatic axillary lymph nodes in patients with newly diagnosed breast cancer

To investigate the ability of diffusion weighted images (DWI) to differentiate between metastatic and nonmetastatic axillary lymph nodes (LNs) in patients with newly diagnosed breast cancer.

Pulmonary varix mimicking arteriovenous malformation

We report here a case of a 44-year-old female with a pulmonary varix. The patient was asymptomatic; a routine chest X-ray incidentally revealed a serpiginous mass in the left hilar region. Computed tomography revealed a serpiginous, dilated vascular structure in the left upper lobe that continued into the lower lobe and was suggestive of an arteriovenous malformation. Pulmonary angiography revealed no arterial abnormality; however, the filling of an abnormally dilated pulmonary vein was observed. Angiography is considered to be the most useful method for the confirmatory diagnosis of pulmonary varices.

MR imaging of malignant primary breast lymphoma: including diffusion-weighted imaging, histologic features, and a literature review

ObjectiveTo investigate the magnetic resonance (MR) imaging characteristics of malignant primary breast lymphoma (PBL), including features on diffusion-weighted imaging (DWI).MethodsThe MR findings of three patients were reviewed retrospectively at our institutions. The signal intensity, shape, enhancement pattern, and DWI findings were examined and correlated with the histologic features. We also reviewed the MR findings of cases of PBL reported in the literature.ResultsThe tumors in our cases showed early enhancement with penetrating vessels on early-phase dynamic MR images and a strong high signal intensity on DWI. The tumors had a cerebroid appearance and septal enhancement on delayed contrast-enhanced MR images, and we speculate that the fibrous tissue seen in the tumors may correspond to septal enhancement. After chemotherapy, all lesions decreased in size, while the ADCs were increased. All of the cases reported in the literature showed early or avid enhancement; this finding was similar to that observed in our cases.ConclusionsAlthough based on a small number of cases, we suggest that strong enhancement with penetrating vessels in masses on early images of dynamic MR, strong high intensity on DWI, a cerebroid appearance, and septal enhancement are useful diagnostic clues for a diagnosis of PBL.

Dumbbell-shaped thoracic hibernoma: computed tomography and magnetic resonance imaging findings

Hibernoma is an uncommon, benign soft tissue tumor that arises in brown adipose tissue. The computed tomography (CT) and magnetic resonance imaging (MRI) findings of hibernomas are similar to those of well-differentiated liposarcoma or angiolipoma. We report the unique appearance of a rare thoracic wall hibernoma, which appeared as a dumbbell-shaped lipomatous tumor across an intercostal region. A dynamic contrast-enhanced study on MRI revealed early enhancement, which corresponded to the branching low-signal intensity on T2-weighted images of the mass.

HIV-Related Cardiac Complications: CT and MRI Findings

OBJECTIVE Cardiovascular complications in patients with HIV infection include myocardial, endocardial, pericardial, and vascular diseases. The complications are caused by the HIV infection itself, opportunistic infections, HIV-related tumors, and the side effects of highly active antiretroviral therapy. The article reviews the CT and MRI findings suggestive of HIV-related cardiovascular diseases. CONCLUSION The cardiovascular complications of HIV infection frequently overlap, making the diagnosis difficult. CT and MRI are useful for the noninvasive evaluation of these complications.

Magnetic resonance imaging features of spontaneously regressed thymoma: report of 2 cases.

The authors describe 2 cases in which thymoma spontaneously regressed. The first patient was a 49-year-old woman with myasthenia gravis. A chest radiograph on admission showed an anterior mediastinal mass that spontaneously decreased in size as shown on a radiograph obtained 2 weeks later. Surgical removal of the mass was performed and the histopathologic examination showed a type B2 thymoma with marked coagulation necrosis in the central area. The second patient was a 46-year-old woman who was hospitalized due to chest and back pain. A chest radiograph on admission showed an anterior mediastinal mass and bilateral pleural effusion. The mass decreased in size and the effusion disappeared as shown on a chest radiograph obtained 2 months later. Computed tomography-guided biopsy was performed, and histopathologic examination revealed thymoma with marked necrosis. In both cases, dynamic contrast-enhanced magnetic resonance images showed peripheral ringlike enhancement of the mass. The clinical and radiologic features of spontaneously regressed thymoma may be different from those of common thymoma.

Left and Right Ventricular Diverticula: Incidence and Imaging Findings on 256-slice Multidetector Computed Tomography

Purpose Cardiac ventricular diverticulum is a rare congenital malformation. The entity is usually asymptomatic but can rarely cause complications and mimic other severe cardiac diseases on imaging. We evaluated the incidence and imaging findings of left and right ventricular diverticula on electrocardiogram-gated 256-slice multidetector computed tomography angiography (MDCTA). Materials and Methods We reviewed 324 patients (188 men; 136 women; mean age, 56±15 y; age range, 7 to 91 y) who underwent retrospective (n=177) or prospective (n=147) electrocardiogram-gated cardiac CTA using a 256-slice MDCT scanner (Brilliance iCT, Phillips Healthcare; slice collimation, 2×128×0.625 mm; gantry rotation time, 270 ms) and searched for ventricular diverticula. We evaluated the incidence, size, location, and CT findings of the ventricular diverticula on the MDCTA images. Results Eighteen ventricular diverticula were detected in 11 patients (incidence, 3.4%; 3 men; 8 women). Fifteen left ventricular diverticula were detected in 11 patients (incidence, 3.4%), and 3 right ventricular diverticula were found in 2 patients (incidence, 0.6%). The left ventricular diverticula were commonly located in the mid-inferoseptal (n=6) and mid-anteroseptal (n=4) walls. The right ventricular diverticula were located in the apical inferoseptal, mid-anteroseptal, and mid-inferoseptal walls. The mean maximal diameter of ventricular diverticula was 10±3 mm (range, 7 to 16 mm). Multiple diverticula were seen in 5 patients (45%) and were commonly found clustered close to one another. Each of 13 ventricular diverticula with images obtained both in systole and diastole showed synchronous contraction with adjacent myocardium, and 4 diverticula completely closed in systole. Conclusions The incidence of left and right ventricular diverticula on 256-slice MDCTA was 3.4% and 0.6%, respectively, an incidence more frequent than in previous reports. The ventricular diverticula were commonly located in the mid-inferoseptal or mid-anteroseptal wall.

Intracellular lipid in ovarian thecomas detected by dual-echo chemical shift magnetic resonance imaging: report of 2 cases.

Thecoma of the ovary is a stromal tumor composed of lipid-containing cells with a variable component of fibroblasts. To our knowledge, there have been no reports in the English literature describing detection of intracellular lipid in thecomas by preoperative imaging. We present 2 cases of thecomas of the ovary, in which intratumoral lipid was detected using dual-echo chemical shift magnetic resonance imaging.