Dai Kakizaki

Increased Water Diffusion in Cerebral White Matter in Alzheimer’s Disease

We investigated the changes in water diffusion in the cerebral white matter in 19 patients with Alzheimers disease (AD), including 11 without and 8 with periventricular hyperintensity (PVH) lesions, using diffusion-weighted magnetic resonance imaging (MRI). The apparent diffusion coefficients in the anterior and posterior white matter were significantly higher in the 19 AD patients than in the 10 age-matched controls. The apparent diffusion coefficients were higher in patients with PVH than in those without. The anisotropic ratios, defined as diffusion restricted perpendicular to the direction of the nerve fibers, were significantly higher in AD patients, even in those without PVH, than in the controls. Our results suggest that mild myelin loss occurs in AD patients even in the apparently normal white matter. A definite loss of myelin and axons, including incomplete infarction, occurs in the white matter, as seen on T2-weighted images as PVH. Studies with diffusion-weighted MRI may allow the characterization of different pathological processes and enable the demonstration of underlying white matter lesions in AD that cannot be visualized by conventional MRI.

Evaluation of chest wall invasion by lung cancer using respiratory dynamic MRI

Conventional CT or MRI has low accuracy in assessing chest wall invasion in patients with peripheral lung cancer. For preoperative evaluation of chest wall invasion by peripheral lung cancer, respiratory dynamic (RD) MRI was carried out in 98 patients in whom conventional CT scan showed that the tumour was abutting the pleural surface, but there was no evidence of definite tumour invasion. We used 1.5‐T MR equipment. RD MR images were acquired by snapshot fast field echo sequence (repetition time = 8, echo time = 3, flip angle = 100) and 25 consecutive images were taken while the patient took deep breaths. These images were evaluated in cine mode to assess tumour movement along the chest wall. Sixty‐one patients underwent surgical resection of the tumour and RD MR findings were compared with those in pathological specimens. RD MR showed free tumour movement along the chest wall in 34 patients. At pathological examination, the RD MR findings were proved correct in all patients. Pathologically, 20 patients had chest wall invasion and their RD MR was positive (sensitivity 100%). There were seven false‐positive results among the 41 patients without chest wall invasion (specificity 82.9%). RD MR may improve the accuracy of conventional CT scan or MRI in the prediction of chest wall invasion of lung cancer, especially in patients in whom the results of conventional CT scan or MRI appear equivocal in the presence of a peripheral mass abutting the chest wall surface without obvious chest wall invasion.

Effect of Gd-EOB-DTPA on T2-weighted and diffusion-weighted images for the diagnosis of hepatocellular carcinoma.

To evaluate the effect of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA) on T2‐weighted imaging (T2WI) and diffusion‐weighted imaging (DWI) for the diagnosis of hepatocellular carcinoma (HCC).

CT scanning of bronchioloalveolar carcinoma: specific appearances

We reviewed CT scans in 38 cases with pathologically proved bronchioloalveolar carcinoma. CT revealed three CT patterns: solitary, pneumonic and diffuse forms. The solitary pattern (22 patients) had a high percentage of air bronchograms (95%), pleural indentation (77%) and spiculation (68%). The pneumonia-like pattern (16 lesions in 10 patients) had air bronchograms in all cases (100%), low attenuation (88%) and protrusion of interlobar fissures (63%). The diffuse form (six patients) had 2 or 3 mm diffuse small nodules scattered throughout the entire lung. CT of bronchioloalveolar carcinoma revealed many findings and was useful in recognizing the tumor distribution and extent. We conclude that CT is helpful for the diagnosis and evaluation of bronchioloalveolar carcinoma.

Venous hemangioma of the mediastinum

Abstract Mediastinal hemangiomas are rare tumors. We present a case of venous hemangioma of the mediastinum. Computed tomography shows anterior mediastinal solid mass without enhancement effects. We believe that it is necessary to include a mediastinal hemangioma for differential diagnosis, when little or no enhancement effects are noted at early and delayed CT examination.

Gallium-67 accumulation to the tumor thrombus in anaplastic thyroid cancer

A sixty-five-year-old woman was hospitalized for examination of swelling in the left arm. Gallium-67 scintigraphy showed the same radioactivity in the left lobe of the thyroid gland and the junction of the internal jugular vein and the subclavian vein. Operation then proved obstruction of the left internal jugular vein and subclavian vein due to tumor thrombus accompanied by anaplastic thyroid cancer. Gallium-67 scintigraphy was extremely useful in grasping the extent and feature of the tumor.

Evaluation of cardiac iron overload in transfusion-dependent adult marrow failure patients by magnetic resonance imaging.

We investigated magnetic resonance imaging T2-star (MRI-T2*) values and left ventricular ejection fraction (LVEF) in 7 adult patients with bone marrow failure with heavy transfusion to elucidate the correlation between cardiac iron overload and dysfunction. We demonstrated a positive correlation between the total volume of red blood cells (RBC) transfusion and ejection fraction. The normal T2* limit value, which represents cardiac siderosis, is probably 200 mL/kg RBC transfusion. Patients with serum ferritin levels of under 5000 ng/mL and who received 200-400 mL/kg RBC transfusion showed mild but progressive decrease of the T2* value without obvious reduction of the ejection fraction, indicating that the T2* value of MRI could be a predictor for cardiac iron deposition before the appearance of myocardial dysfunction. Transfused RBC amount of >400 mL/kg or rapid elevation of ferritin level of >5000 ng/mL might be warning sign for critical cardiac dysfunction. Since iron overload of the heart is a major factor affecting co-morbidity of bone marrow failure, MRI evaluation of cardiac iron overload and functional disturbance in adult non-thalassemic patients is essential.

Multiplanar reconstruction MR image of primary adenoid cystic carcinoma of the central airway: MPR of central airway adenoid cystic carcinoma

Multiplanar reconstruction (MPR) is a method that allows free selection of computerized reconstruction images. We reviewed a total of six MPR magnetic resonance (MR) examinations in five cases of adenoid cystic carcinoma of the central airway, which is a rare low-grade malignant tumor. MPR MR provides images either longitudinally or at right angles to the longitudinal axis of the trachea and main bronchi, so it was useful to diagnose tumor extent along airways more precisely and to evaluate therapeutic effects. MPR MR may help in planning therapeutic strategy and in posttherapeutic follow-up.

High-resolution computed tomographic findings of small peripherally located squamous cell carcinoma.

With the spread of high-resolution computed tomography (HRCT) screening for lung cancer, we are increasingly faced with the need to determine whether certain small lesions are benign or malignant. The features of small adenocarcinomas have been clarified but not those of squamous cell carcinoma. The objective of our study was therefore to clarify the HRCT findings of peripherally located squamous cell carcinomas less than 2 cm in maximum dimension. Subjects consisted of 27 consecutive pathologically proven cases of peripherally located squamous cell carcinoma that were less than 2 cm in maximum dimension. HRCT findings of all 27 cases were analyzed retrospectively and independently by three radiologists who were unaware of the pathological diagnosis, and decisions were reached by consensus with special attention to 10 review points. Internal characteristic features included calcification, cavity formation, and air bronchogram. Tumor margin features included spiculation, notching, irregularity, and ground-glass opacity. Surrounding structural features consisted of pleural indentation, pulmonary emphysema, and satellite lesions. The presence of irregularity (70.4%), surrounding pulmonary emphysema (70.4%), and pleural indentation (51.9%) was observed frequently. No mass was accompanied by calcification. HRCT images of peripherally located squamous cell carcinoma suggested that the demonstration of irregularity, surrounding pulmonary emphysema, pleural indentation, and absence of calcification may contribute to the accurate CT diagnosis of small peripheral squamous cell carcinoma.

Myometrial invasion and cervical invasion by endometrial carcinoma: evaluation by CO2-volumetric interpolated breathhold examination (VIBE).

To assess myometrial invasion and cervical invasion by endometrial carcinoma, using CO2‐volumetric interpolated breathhold examination (VIBE) enabling more precise evaluation of depth of tumor invasion.