Shigeru Ehara

Single shot fast spin echo diffusion-weighted MR imaging of the spine: Is it useful in differentiating malignant metastatic tumor infiltration from benign fracture edema?

PURPOSE This study aims to evaluate the usefulness of single shot fast spin echo diffusion-weighted MR imaging (DWSSFSE) in differentiating malignant metastatic tumor infiltration of vertebral bone marrow from benign vertebral fracture edema. MATERIALS AND METHODS Forty-six consecutive patients with 59 acute osteoporotic or traumatic vertebral fractures (mean age = 59) and 31 patients with 98 vertebral metastasis including 20 pathologic fractures (mean age = 53) were included in this study. Diffusion-weighted MR images were obtained by single-shot fast spin echo technique with diffusion gradient (b = 500 s/mm2, TR/TE: 5002/99) by using a 1.5 T MR scanner (Signa MR/i; GE Medical Systems, Milwaukee, WI, USA). T1- and T2-weighted images and short inversion time inversion-recovery (STIR) images were available in all 157 lesions, while contrast-enhanced images were available in 98 metastatic lesions. We evaluated signal intensity patterns on DWSSFSE in 157 lesions, which showed low signal intensity on T1-weighted images in both benign fractures and metastasis. The lesions on DWSSFSE were categorized as low, intermediate, and high signal intensity relative to presumed normal vertebra by concordant inspection of two experienced musculoskeletal radiologists. RESULTS In benign fractures, DWSSFSE images showed low signal intensity in 56 vertebrae (95%) in 43 patients (93%) and intermediate signal intensity in only 3 vertebrae (5%) in 3 patients (7%). On the other hand, metastases most commonly had low signal intensity in 57 vertebrae (58%) in 25 patients (80%), intermediate signal intensity in 35 vertebrae (36%) in 16 patients (52%), and high signal intensity in 6 vertebrae (6%) in 3 patients (10%). Thus, intermediate and high signal intensities are far more common than benign fractures. Such differences in signal intensity were statistically significant (chi-square test, P < .05). High or intermediate signal intensity on DWSSFSE was highly specific for the diagnosis of metastatic tumor infiltration of the spine (sensitivity: 42%; specificity: 95%; true positive rate: 93%; false negative rate: 52%). CONCLUSIONS DWSSFSE of the spine may be useful in differentiating metastatic tumor infiltration of vertebral bone marrow from benign fracture edema.

Difference in Tracer Delay–induced Effect among Deconvolution Algorithms in CT Perfusion Analysis: Quantitative Evaluation with Digital Phantoms

Institutional review board approval and informed consent were obtained. The purpose was to evaluate the differences in tracer delay-induced effects of various deconvolution algorithms for computed tomographic (CT) perfusion imaging by using digital phantoms created from actual source data. Three methods of singular value decomposition (SVD) were evaluated. For standard SVD (sSVD), the delays induced significant errors in cerebral blood flow and mean transit time. In contrast, for block-circulant SVD (bSVD), these values remained virtually unchanged, whereas for delay-corrected SVD (dSVD), mild changes were observed. bSVD was superior to sSVD and dSVD for avoiding the tracer delay-induced effects in CT perfusion imaging.

Paravertebral ligamentous ossification: DISH, OPLL and OLF

This is an overview of paravertebral ligamentous ossification based on our 5-year experience in ossification of posterior longitudinal ligament (109 cases) and ossification of ligamentum flavum (18 cases). Paravertebral ligamentous ossification is designated as the disorder caused by frequently coexisting ossification of paravertebral ligaments, DISH, OPLL, and OLF. The frequency of the occurrence of isolated ossification of PLL and OLF in Japan is still uncertain. DISH, which is not rare in Europe or North America, is frequently associated with ossification of the posterior aspect of the vertebral bodies, but it may be less symptomatic. The major cause of the probably higher incidence of symptomatic patients in Japan may be due to associated narrowing of the spinal canal.

Reasons for Rejection of Manuscripts Submitted to AJR by International Authors

OBJECTIVE The objective of this study was to promote publication by international authors in AJR by analyzing the reasons for rejection of manuscripts. MATERIALS AND METHODS Data available through the electronic system for review of submitted manuscripts were analyzed over a 2-year period with regard to country of origin, type of the manuscript, decision of the editors, and reason for rejection. Countries with more than 50 submitted manuscripts were selected, and rejection rates and reasons for rejection determined by one of the editors were compared. RESULTS Eighteen countries had more than 50 manuscript submissions, and the rejection rates ranged from 22.6% to 73.4%. Countries with high rates of submission of reports of original research, including Clinical Observations manuscripts, had high acceptance rates. Countries in which English is the primary language had higher acceptance rates than those in which English is not the primary language (29.1% vs 40.3%, p < 0.05). Countries with English as the primary language, including Canada, the United Kingdom, and Australia, had rejection patterns similar to that of the United States. Language problems were not a major reason for rejection, except for manuscripts from China. Lack of new or useful knowledge was by far the most common reason for rejection in all countries (44-76% of all rejections). CONCLUSION High-quality scientific work is key to overcoming barriers to publication. Designing an appropriate study that answers a clearly defined and pertinent question is an important first step. Language problems were not a major cause of rejection, except for manuscripts from China.

Peritumoral edema in osteoid osteoma on magnetic resonance imaging

Abstract Objective.To determine whether there is a relationship between the peritumoral edema caused by osteoid osteoma seen on magnetic resonance (MR) imaging and the patient’s age, duration of symptoms, or location of the lesion. Design and patients. All histologically proven osteoid osteomas seen in our institutions during a 5-year period in patients with known age, gender, duration of symptoms, and available radiological and MR imaging examinations were included in this study. The extent of the edema in the bone marrow and extraosseous soft tissue around the nidus of osteoid osteoma on T2-weighted MR imaging were graded from 1 (nonexistent) to 4 (extensive) by two masked observers. The relationships between the patient’s age, duration of symptoms, and location of lesions were evaluated by Pearson’s correlation coefficient and analysis of variance. Results.Twenty-seven cases met the inclusion criteria. The observer agreement on grading was good. Patients of 15 years of age or younger had significantly higher grades than patients older than 15 years. There was a moderate negative linear correlation between the patient’s age and peritumoral edema. No significant relationship was identified between edema and the duration of symptoms or the location of lesions. Conclusion. Osteoid osteomas in younger patients tend to be associated with more extensive peritumoral edema.

Posterior interosseous nerve palsy caused by parosteal lipoma of proximal radius

Abstract Lipomas are common benign soft tissue tumors which tend to be indolent, and symptoms caused by nerve compression are unusual. However, a parosteal lipoma, occurring adjacent to the proximal radius may easily cause paralysis of the posterior interosseous nerve because of a specific anatomical relationship of these structures in that area. Two cases of parosteal lipoma of the proximal radius causing paralysis of the posterior interosseous nerve are reported. CT and MR imaging demonstrate the characteristic fatty mass around the radius and are specific in making the diagnosis. Surgical excision should be promptly performed to ensure optimal recovery from the nerve paralysis.

Cervical spine injury in the elderly: imaging features

Abstract An increase in the elderly population has resulted in an increased incidence of cervical spine injury in this group. No specific type of cervical spine trauma is seen in the elderly, although dens fractures are reported to be common. Hyperextension injuries due to falling and the resultant central cord syndrome in the mid and lower cervical segments due to decreased elasticity as a result of spondylosis may be also characteristic. The imaging features of cervical spine injury are often modified by associated spondylosis deformans, DISH and other systemic disorders. The value of MR imaging in such cases is emphasized.

Transient decrease in cerebral white matter diffusivity on MR imaging in human herpes virus-6 encephalopathy

We report a 16-month-old boy with human herpes virus-6 (HHV-6) encephalopathy showing transient abnormalities of the cerebral white matter on magnetic resonance imaging. Diffusion-weighted imaging (DWI) demonstrated diffuse high signal intensity in the bilateral cerebral white matter areas. The signal changes on DWI subsequently resolved, and cerebral atrophy resulted. The transient decrease in the cerebral white matter diffusivity seen in the present case may reflect axonal involvement secondary to the glial or neuronal damage in HHV-6 encephalopathy.

Angiosarcoma associated with chronic lymphedema (Stewart-Treves syndrome) of the leg: MR imaging

Abstract Magnetic resonance (MR) imaging findings of two patients with Stewart-Treves syndrome are presented. MR imaging showed edematous changes in the subcutaneous fat and skin masses that proved to be angiosarcomas. MR signal intensity of the tumor was low compared with fat on T1-weighted images and intermediate and heterogeneous on T2-weighted images. In one patient, administration of intravenous Gd-DTPA showed marked enhancement in the early phase, which persisted until the delayed phase. These finding on dynamic MR imaging may reflect the abundant vascular spaces seen in these tumors.

Pasteurized intercalary autogenous bone graft: radiographic and scintigraphic features.

Abstract  Objective. Pasteurized autogenous bone graft sterilized at a low temperature (60°C) is one option for reconstruction after resection of bone and soft tissue tumors. The purpose of this investigation was to assess the normal and abnormal radiographic and scintigraphic findings of pasteurized intercalary autogenous bone graft after resection of bone and soft tissue sarcomas. Design. This was a retrospective evaluation of the radiography and bone scintigraphy findings in patients after treatment of bone and soft tissue sarcomas using an intercalary pasteurized autogenous bone graft. Patients. Among 10 consecutive patients, eight had intercalary grafts, and they constitute the subjects of this study. All available radiography and bone scintigraphy findings were reviewed for the healing process and the possibility of complications. Results and conclusions. Healing and incorporation of the graft were observed in five patients during the follow-up, but the other three did not heal satisfactorily. Rapid incorporation of pasteurized autogenous bone graft can be demonstrated by means of radiography and bone scintigraphy.