Hajime Nakata

The radiological findings in chronic expanding hematoma

Abstract  Objective. To identify the characteristic MRI findings of chronic expanding hematoma correlated with the pathology. Design and patients. Three patients who had a chronic expanding hematoma involving the musculoskeletal system were reviewed retrospectively. Results and conclusion. Huge soft tissue masses suggestive of malignancy with destruction of the bony structure were revealed on radiography and computed tomography. MRI showed the masses to exhibit heterogeneous signal intensity on both T1- and T2-weighted images with a peripheral rim of low signal intensity, reflecting the central zones of fluid collection due to fresh and altered blood with a wall of collagenous fibrous tissue. These MRI findings were seen in all three patients and are considered to be characteristic; they assist in differentiation from neoplasm in consideration of the history of trauma or surgery.

Signal intensity characteristics of mediastinal cystic masses on T1-weighted MRI.

Objective We evaluated the intracystic MR signal intensity of mediastinal cystic tnasses to identify characteristic intensity patterns according to histologic type. Materials and Methods Magnetic resonance imaging was performed on 26 cystic mediastinal masses consisting of 8 thymic cysts, 5 bronchogenic cysts, 4 pericardial cysts, 5 cystic teratomas, and 4 cystic neurogenic tumors. Signal intensity ratios of each cyst to muscle were calculated on T1-weighted imaging. Surgical records were reviewed to document the presence of intracystic hemorrhage. Chemical analysis of intracystic fluid was performed in three cases. Results Bronchogenic cysts, cystic teratomas, and cystic neurogenic tumors had relatively high levels of signal intensities. Each pericardial cyst had a lower signal intensity than tnuscle. The signal intensities of thymic cysts were variable. Intracystic hemorrhage was present in 1 bronchogenic cyst, 2 cystic neurogenic tumors, 4 cystic teratomas, and 3 thymic cysts. No hemorrhage was found in any of the pericardial cysts. Sebaceous fluid was present in 1 cystic teratoma. Conclusion The varying intensities of different cysts were considered to reflect the nature of the intracystic fiuid. Since the nature of the fluid can reflect the histology to some extent, T1-weighted MRI will help to differentiate cystic tnediastinal masses. Index Terms Mediastinum, cysts—Histology—Magnetic resonance imaging.

MRI of bronchogenic cysts.

The MR appearance of eight bronchogenic cysts is reported. All the cysts appeared homogeneous and were of very high signal intensity, approximating that of CSF on spin-echo T2-weighted imaging, and of relatively high intensity, between that of muscle and subcutaneous fat on T1-weighted imaging. The cysts were round or ovoid and were well demarcated. These findings are consistent with the fluid-containing properties of cysts.

CT of pulmonary metastases with pathological correlation

CT, including high-resolution CT, has become an essential means of imaging to evaluate pulmonary metastases. The underlying pathological processes of pulmonary metastases can be observed well on CT images, but they are not always specific. Several important CT features correlate with histopathological findings: (1) margin of nodule; (2) hemorrhage accompanying a metastatic nodule; (3) calcification; (4) cavitation; (5) sterilized metastasis; (6) small metastatic nodules in the lobules; (7) lymphangitic carcinomatosis; (8) tumor emboli; and (9) pleural metastases. For reasonable use of CT in pulmonary metastases, these various CT manifestations and their limitations must be understood.

MRI findings including gadolinium-enhanced dynamic studies of malignant, mixed mesodermal tumors of the uterus: differentiation from endometrial carcinomas

Abstract. Our objective was to evaluate the usefulness of MRI including dynamic study in differentiating malignant, mixed mesodermal tumor (MMMT) from endometrial carcinoma (EC). The MR images were reviewed in 4 patients with histologically confirmed MMMT and 11 patients with EC. Flow voids inside and/or around the tumors were seen in 2 patients with MMMT but not in any EC cases. In dynamic studies, all 4 patients with MMMT showed areas of early and persistent marked enhancement similar to that of the myometrium, mixed with areas of gradual and delayed marked enhancement. The portions showing early and persistent enhancement histologically corresponded to predominantly sarcomatous components with prominent vascularity. Ten of 11 ECs did not show such enhancement and only one showed a rapid enhancement in the early phase which was diminished in the delayed phase. The MR imaging with a gadolinium-enhanced dynamic study seems to be useful in differentiating MMMT from EC.

Treatment strategy for patients with surgically discovered N2 stage IIIA non-small cell lung cancer

BACKGROUND The treatment strategy for patients with non-small cell lung cancer and clinically negative, but surgically detected mediastinal lymph node metastasis (surgically discovered N2 disease) is controversial. METHODS From August 1979 through December 1994, 53 patients with non-small cell lung cancer were found to have surgically discovered N2 disease. We retrospectively studied the clinical characteristics and the factors that influenced the prognosis in these patients. RESULTS The 3-year and 5-year survival rates and the median survival for the 53 patients with surgically discovered N2 disease were 44%, 21%, and 26 months. Two thirds of the patients had adenocarcinoma. Only complete resection affected long-term survival; adjuvant therapy had no effect on survival. In regard to lymph node status, a single metastatic focus in the aortic area was associated with long-term survival. CONCLUSIONS Patients with adenocarcinoma may require histologic determination of N2 disease. Complete resection, including extensive and complete mediastinal lymph node dissection, is warranted in patients with surgically discovered N2 disease. In particular, when the aortic lymph node (including stations 5 and 6) alone is involved, the patients should undergo as complete a resection as possible.

Pulmonary hemorrhage in patients with systemic lupus erythematosus

Five patients with pulmonary hemorrhage associated with SLE were studied. Chest radiographs showed extensive alveolar opacity immediately after hemoptysis or dyspnea in four patients. In one patient an interstitial pattern seen initially progressed rapidly to an alveolar pattern. Three patients were successfully treated with corticosteroids and are doing well at present. The diagnosis and treatment of pulmonary hemorrhage is vital to patients with SLE. In the appropriate clinical setting chest radiographic findings of acute alveolar disease should suggest pulmonary hemorrhage, and empiric treatment with corticosteroids should be considered.

Optimal beam quality for chest computed radiography

RATIONALE AND OBJECTIVES Optimal x-ray beam quality for chest computed radiography (CR) has not been determined. To investigate the optimal beam quality for chest CR, the authors measured the radiographic contrasts and compared the image quality of chest CR and screen-film (SF) radiographs using various x-ray tube voltages. METHODS Chest CR and SF radiographs were obtained on a phantom lung and human volunteers with or without a variety of simulated lung opacities using various x-ray tube voltage levels. Exposures were set to maintain identical patient exposure doses for all images. The contrast between peripheral lung and rib or heart was measured on these images and the differences were compared. The quality of the images of each simulated opacity was evaluated by five radiologists using a five-point grading scale. RESULTS Contrast between peripheral lung and rib or heart increased on CR images obtained by lowering the tube voltage from 140 to 80 kV, but the degree of increase was less than half the increase on SF images. The CR images of the simulated opacities obtained using a lower tube voltage were judged to be superior to those obtained with a higher tube voltage. Scattered radiation was reduced on CR images with a lower tube voltage. CONCLUSION The image quality of chest CR was improved by using a lower tube voltage than that used for conventional SF chest radiography. Considering the problem of tube loading in clinical applications, a tube voltage of 100 kV is recommended for chest CR.

Irreversible data compression in chest imaging using computed radiography: an evaluation

We studied the feasibility of a recently developed 20:1 to 25:1 compression technique for computed radiography (CR) using lung phantom images, and clinical cases were evaluated. We compared one original and two reconstructed CR films of the same image using compression ratios of 10:1 to 15:1, and 20:1 to 25:1, and the deterioration of image quality was carefully checked. Evaluation by subjective ranking of various abnormal opacities created for phantoms and clinical cases showed deterioration of image quality with 20:1 to 25:1 compression images. This was greatest for a single linear opacity (thin line) and least for reticulonodular opacities. Receiver operating characteristics (ROC) for pneumothorax, pulmonary nodules and reticulonodular opacities in newborns, infants, and adults revealed no significant differences among the original 10:1 to 15:1, and 20:1 to 25:1 compression images. We conclude that this new method of data compression of CR images is clinically applicable and useful.

Giant Meckel diverticulum containing enteroliths diagnosed by computed tomography and sonography

A 23-year-old male patient with giant Meckel diverticulum containing enteroliths is presented. Computed tomography (CT) and sonography were useful for correctly suggesting the diagnosis. The unique manifestations of this rare lesion are described.