Tsuneaki Nakagawa

Anisotropic diffusion in kidney: Apparent diffusion coefficient measurements for clinical use

The purpose of this study was to evaluate anisotropy of the kidney by measurements of the apparent diffusion coefficient (ADC) using commercially available magnetic resonance (MR) imaging. Fifty‐one consecutive patients underwent diffusion‐weighted echoplanar MR imaging of the upper abdomen with five different strengths of motion probing gradients (b = 1.51, 55.3, 36.6, 317, and 932 sec/mm2) applied along the z‐axis. Four ADC values for the upper pole and central portion of the kidney were calculated from four different b‐value ranges and compared. The ADCs for the kidney calculated in the lower b‐value ranges were significantly higher than those in the higher ranges. The ADCs for the upper pole portion were significantly higher than those for the central portion except for one in the highest b‐value range. Diffusion in the kidney is anisotropic, probably due to the kidneys radially oriented structures such as renal vessels and tubules. J. Magn. Reson. Imaging 2000;11:156–160.

Takayasu arteritis: diagnosis with breath-hold contrast-enhanced three-dimensional MR angiography.

The purpose of the study was to determine the diagnostic accuracy of breath‐hold contrast‐enhanced three‐dimensional (3D) magnetic resonance (MR) angiography in Takayasu arteritis. Thirty patients suspected of having Takayasu arteritis were examined with MR angiography and conventional angiography. Takayasu arteritis was diagnosed in 20 of these patients. MR angiography was performed using a 1.5‐T system after bolus injection of 0.1 mmol/kg of gadodiamide. MR angiography clearly depicted various vascular lesions in the aorta and its major branches in all 20 patients with Takayasu arteritis. It also depicted pulmonary artery lesions in 10 (50%) of the 20 patients. MR angiography accurately depicted 323 (98%) of 330 arteries, but 7 (2%) stenotic arteries were overestimated as occluded. The sensitivity and specificity of MR angiography for the diagnosis of Takayasu arteritis were both 100%. Breath‐hold contrast‐enhanced 3D MR angiography clearly depicts various vascular lesions in both the systemic and pulmonary arteries in Takayasu arteritis, thus allowing a definitive diagnosis of Takayasu arteritis. J. Magn. Reson. Imaging 2000;11:481–487.

The relation between an esophageal cancer and associated cancers in adjacent organs

Background. The relation between esophageal cancers and head and neck tumors was studied in order to improve the treatment results in patients with multiple cancers.

Neck node metastasis after successful brachytherapy for early stage tongue carcinoma

BACKGROUND AND PURPOSE The accuracy of factors for predicting lymph node metastasis in patients with early-stage (stage I and II) mobile tongue carcinoma and prognostic factors associated with the clinical and pathological findings of lymph node metastasis were examined. MATERIAL AND METHODS Between 1971 and 1998, 616 patients with early stage mobile tongue carcinoma were treated by brachytherapy with or without external irradiation. Neck lymph node metastasis occurred in a total of 237 cases, and 191 of them were not associated with primary failure. Neck dissection was performed in 169 of these 191 cases, and 16 cases were treated by radiotherapy. A pathological analysis was possible in 159 of the 169 neck dissection cases. RESULTS There were 88 tongue cancer recurrences, and the incidence of neck metastasis was 38% (191/528) in the cases of primary controlled early tongue carcinoma, and 25% (38/151) and 41% (153/377), in stage-I and -II carcinoma, respectively. Neck metastasis was diagnosed within 12 months in 80% of cases, and within 24 months in 95%. Macroscopic appearance, tumor thickness and tumor length were identified as significant risk factors by a univariate analysis, but macroscopic appearance was the only significant risk factor identified by a multivariate analysis (P<0.001). The incidence of cervical lymph node metastasis was 62% among the invasive/ulcerative type tongue carcinomas, and was lower among the superficial type and exophytic/nodular type (20 and 35%, respectively). Regional and/or distant failure occurred in 75 of the 169 neck dissection cases (44%). The incidence of regional/distant failure was extremely high (49/68=72%) in the extra-nodal invasion group, and extra-nodal invasion was found even in small metastatic node less than 1 cm in length (20%). CONCLUSIONS The macroscopic appearance of the primary tongue carcinoma has a major impact on the incidence of lymph node metastasis in patients with early tongue cancer, and extra-nodal invasion was the dominant risk factor for regional and distant failure. Treatment policy for clinically negative neck metastasis in early tongue cancer patients should be determined after considering the possibility of neck metastases and the morbidity associated with elective neck dissection.

High-resolution turbo magnetic resonance angiography for diagnosis of Moyamoya disease.

Background and Purpose— High-resolution turbo MR angiography with zero-filling interpolation (ZFI) technique is a new vascular imaging method with reduced scan time. The purpose of the present study was to evaluate high-resolution turbo MR angiography for the diagnosis and assessment of moyamoya disease. Methods— Forty-six patients suspected of having moyamoya disease were examined with high-resolution turbo MR angiography with the ZFI technique, MRI, and conventional angiography. Moyamoya disease was diagnosed in 42 of these patients. Blind, separate interpretation of the images was performed. Results— High-resolution turbo MR angiography and MRI accurately evaluated 349 (95%) and 325 (88%) of 368 arteries, respectively, but the degree of stenosis was overestimated in the other arteries. MR angiography and MRI depicted basal cerebral moyamoya vessels in 82 (98%) and 82 (98%) of 84 hemispheres, respectively. MR angiography also depicted leptomeningeal and transdural collateral vessels in 51 (100%) of 51 hemispheres and in 38 (88%) of 43 hemispheres, respectively. The sensitivity and specificity of high-resolution turbo MR angiography for the diagnosis of moyamoya disease were 98% and 100%, respectively. Conclusions— High-resolution turbo MR angiography in reduced scan time is highly accurate in the assessment of both steno-occlusive lesions and collateral vessels in moyamoya disease, thus providing a highly accurate (98%) diagnosis and assessment of moyamoya disease.

Metastases to pelvic lymph nodes from carcinoma in the pelvic cavity: diagnosis using thin-section CT.

OBJECTIVE To assess the accuracy of thin-section computed tomography (CT) in the diagnosis of pelvic lymph nodes affected by metastatic cancer. METHODS Incremental CT was performed by obtaining 3 mm sections with 3 mm intervals in 34 patients who had carcinoma in the pelvis, pre-operatively and prospectively. CT diagnoses were made before surgery using the cine mode with a manual trackball. Lymph nodes with a maximum short axis diameter of greater than 5 mm were considered enlarged. RESULTS The accuracy, sensitivity, specificity, positive and negative predictive values of CT diagnoses were 79.7%, 54.5%, 84.9%, 42.9% and 90.0% on a hemipelvis basis; and 79.4%, 85.7%, 77.8%, 50.0% and 95.5% on a patient basis, respectively. There was only one false-negative case on a patient basis analysis. CONCLUSION Because of a fairly high negative predictive value, negative thin-section CT can be considered an alternative to surgical lymphadenectomy. This is clinically important as unnecessary staging operations and extended surgery are avoided.

Indocyanine Green Angiography of Retrobulbar Vascular Structures in Severe Myopia

PURPOSE To evaluate angiographic findings of retrobulbar arteries and veins in severely myopic patients. METHODS We examined 416 severely myopic eyes (213 patients) with refractive errors greater than -8.25 diopters using indocyanine green videoangiography. A control group of 74 eyes (37 patients) had refractive errors within plano +/- 3 diopters. Four severely myopic patients underwent computed tomographic angiography to identify the entire intraorbital course of retrobulbar veins. RESULTS Of 416 severely myopic eyes, 231 (55.5%) exhibited retrobulbar arteries, which were tortuous and pulsatile behind the posterior pole of the globe. Retrobulbar arteries connected directly with choroidal arteries temporal to the macular area. In 17 of these 231 eyes, retrobulbar arteries were also observed nasal to the optic nerve head, continuous with the Zinn-Haller ring around the optic nerve head and directly connected with choroidal arteries. In 39 severely myopic eyes (31 patients), indocyanine green angiography disclosed retrobulbar veins, most of which coursed vertically just behind the posterior pole of the globe. These retrobulbar veins originated as an inferior vascular network of the inferior orbital vein and drained into the superior orbital vein in the upper orbit. CONCLUSION Retrobulbar arteries observed in this study were temporal and nasal short posterior ciliary arteries. Only the lateral collateral vein, which was one of the collateral channels between the superior and inferior orbital veins, was visible in severely myopic eyes. Indocyanine green angiography is useful in evaluating retrobulbar vascular structure in severely myopic eyes.

Comprehensive analysis of perfusion scintigraphy in Takayasu's arteritis.

One hundred eighty perfusion lung scans of 120 patients with Takayasus arteritis were retrospectively evaluated. Lung scans were abnormal in 76% of the patients. Lung scans could be classified into four groups, according to the pattern of perfusion defects. Early involvement occurred in the upper lobes, and the middle and lower lobes were involved at a later stage. The data obtained by physiological examination (spirography and arterial blood gas analysis) showed a weak relationship with the severity of perfusion lung scan findings. In addition, repeated lung scans were found to be easy and reliable in the follow-up period of pulmonary artery involvement.