Hayao Shiga

MRI of cervical intervertebral discs in asymptomatic subjects

We studied degenerative changes in the cervical intervertebral discs of 497 asymptomatic subjects by MRI and evaluated disc degeneration by loss of signal intensity, posterior and anterior disc protrusion, narrowing of the disc space and foraminal stenosis. In each subject, five disc levels from C2-C3 to C6-C7 were evaluated. The frequency of all degenerative findings increased linearly with age. Disc degeneration was the most common observation, being present in 17% of discs of men and 12% of those of women in their twenties, and 86% and 89% of discs of both men and women over 60 years of age. We found significant differences in frequency between genders for posterior disc protrusion and foraminal stenosis. The former, with demonstrable compression of the spinal cord, was observed in 7.6% of subjects, mostly over 50 years of age. Our results should be taken into account when interpreting the MRI findings in patients with symptomatic disorders of the cervical spine.

Cervical curvature in acute whiplash injuries: prospective comparative study with asymptomatic subjects

The cervical curvature of 488 patients with acute whiplash injury was prospectively studied by comparison with 495 asymptomatic healthy volunteers. Plain radiography of the cervical spine in the neutral position was evaluated qualitatively. No significant difference was noted in frequencies of non-lordotic cervical curvature and local angular kyphosis between acute whiplash injury patients and asymptomatic subjects. No significant association was apparent between clinical symptoms and cervical curvature. These results suggest that non-lordotic cervical curvature and angular kyphosis in acute whiplash injury patients constitute normal variants rather than pathological findings.

Trigeminal neuralgia and hemifacial spasm caused by a tortuous vertebrobasilar system

The case of a 66-year-old woman who developed both trigeminal neuralgia and hemifacial spasm caused by a tortuous vertebrobasilar system is reported. Vertebral angiography showed a dilated and elongated basilar artery overlying the porus acusticus of the internal auditory canal. Double-contrast computed tomography scanning was very useful in evaluating this abnormality. Vascular decompression was performed by using a fenestration clip.

Computed tomography of malignant tumors of the nasal cavity and paranasal sinuses

Staging of malignant tumors of the nasal cavity and paranasal sinuses by computed tomography (CT) was studied in a total of 49 patients, 33 with squamous cell carcinoma and 16 with tumors of other histologic types. Involved sites by the tumor were studied, and clinical staging was made using CT findings alone according to AJC classification for maxillary sinus tumors. Surgical findings for comparison were available for most cases. Of 33 squamous cell carcinomas and of 16 tumors with other histologic types, the maxillary sinus was the site of origin in 29 and eight, respectively. Of these 37 maxillary sinus tumors, 11 were staged T3, 26 T4, and none was staged T1 or T2. None of these tumors were down staged, and one T3 was upstaged after surgical procedures, although all sinuses were not explored in some cases. Sinusitis due to obstruction was indistinguishable from the tumor without bone destruction. And the determination of the site of origin was difficult in some cases. Despite these, CT should be used for pretreatment evaluation of the tumors of these sites.

Orbital high resolution magnetic resonance imaging with fast spin echo in the acute stage of Leber’s hereditary optic neuropathy

Some evidence suggests that the primary locus of the lesion in Leber’s hereditary optic neuropathy (LHON) may be intraocular rather than retrobulbar. To clarify this issue, the condition of the retrobulbar portion of the optic nerve was evaluated in patients with the acute stage of LHON. High resolution MRI with fast spin echo sequences of the optic nerve complex in the orbit was carried out. Five patients with acute stage LHON were compared with seven patients with acute stage optic neuritis. On T2 weighted fast spin echo MRI, signal changes did not appear in the retrobulbar optic nerve complex in acute stage LHON. By comparison, patients with optic neuritis showed pronounced high signals in the optic nerve. Subsequent orbital MRI in the atrophic stages of the same patients with LHON showed an increase in signal intensity in the optic nerve toward the orbital apex in both eyes. The present results support the hypothesis that a primary lesion in LHON may be intraocular.

Maxillary squamous cell carcinomas staged by computed tomography

In 72 patients with maxillary squamous cell carcinoma, computed tomography (CT) alone was used for T-staging according to the AJC classification. Five, 31, and 36 tumors were diagnosed as T2, T3, T4, respectively. In N0 patients with a minimum follow-up of 2 years, local control rates for T2, T3, and T4 tumors were 33% (1/3), 64% (16/25) and 38% (9/24), respectively. Addition of maxillectomy to treatment seemed to have improved the local prognoses in T3 and T4 tumors. High radiation doses of 60 Gy or more seemed to be beneficial for patients with T3 tumors and without maxillectomy. CT will be of great help in classifying tumors objectively. But more importantly, it will reveal resectability and dictate treatment of choice by delineating the tumor extent precisely.

MR angiography of intracranial aneurysms: a comparison of 0.5 T and 1.5 T.

The objective of this paper is to compare the diagnostic efficacy of 3 DFT time-of-flight MR angiography (MRA) at middle-field-strength and high-field-strength in diagnosis of intracranial aneurysms. Thirty-one patients, including 26 patients with angiographically confirmed intracranial aneurysms (n = 28), underwent MRA at 0.5 and 1.5 T. Images were interpreted by six trained observers who were blinded to diagnosis. Twelve projections of MRA of the circle of Willis, by maximum-intensity projection algorithm, were reviewed using continuous confidence-judgement scales. It was found that MRA at 1.5 T was more sensitive than that at 0.5 T in detection of aneurysms. The sensitivity of six observers ranged between 50 and 64% (mean 56%) at 0.5 T, and between 61 and 86 86% (mean 75%) at 1.5 T. In the smaller aneurysms less than 5 mm, the differences between the units became greater. The sensitivity for small aneurysms ranged from 23 to 54% (mean 32%) at 0.5 T, and from 31 to 69% (mean 58%) at 1.5 T. Our conclusion was that high field strength confers higher accuracy in the detection of intracranial aneurysms with MRA with current-generation MR imagers.

Evaluation of the Eustachian Tube in Normal Subjects and in Patients with Otitis Media with Effusion by High Resolution Computerized Tomography

In recent years, tests of Eustachian tube function have undergone remarkable development. In contrast, radiological techniques of examination of the Eustachian tube have not gained general popularity, as they require too much labor to be included in routine tests. For the past 2 years, we have investigated the use of high-resolution computed tomography (CT) in the examination of the normal anatomy of the Eustachian tube and its pathological state in patients with middle ear diseases, especially intractable otitis media with effusion (OME).

The neuroradiological findings in a case of cerebral tuberculoma

SummaryThis paper describes the neuroradiological findings in a case of cerebral tuberculoma. Computed tomography demonstrated a mass in contact with the cranial bone with marked contrast enhancement and accompanied by perifocal cerebral edema. External carotid angiography revealed a homogenous stain supplied from the middle meningeal artery. Furthermore, by radioisotope scan it appeared to be a region of increased uptake with a comparatively clear border and was thereby misdiagnosed as meningioma.

Diagnostic Imaging of Bone Metastasis from Breast Cancer

Conclusion1)Bone scintigraphy is the optimal screening procedure for bone metastasis from breast cancer. The question remains whether bone scintigraphy, from the standpoint of cost-effectiveness, should be performed in all breast cancer patients.2)FDG-PET is anticipated to become more widely available in the near future for the detection of osseous and systemic metastasis.3)X-ray CT, MRI and bone SPECT scanning should be properly used for detailed bone metastasis examination.4)Gd-GTPA-enhanced MRI is of value in evaluating the therapeutic efficacies of treatments for bone metastasis.5)Nuclear medicine imaging procedures (such as bone scintigraphy and99mTc-MIBI scintigraphy) are anticipated to aid in the selection of appropriate therapeutic options for bone metastasis.