Yoshiko Hayashida

Monitoring therapeutic responses of primary bone tumors by diffusion-weighted image: Initial results.

The purpose of our study was to investigate whether quantitative diffusion-weighted images (DWI) were useful for monitoring the therapeutic response of primary bone tumors. We encountered 18 osteogenic and Ewing sarcomas. Magnetic resonance (MR) images were performed in all patients before and after therapy. We measured the apparent diffusion coefficient (ADC) values, contrast-to-noise ratio (CNR), and tumor volume of the bone tumors pre- and posttreatment. We determined change in ADC value, change in CNR on T2-weighted images (T2WI), change in CNR on gadopentetate dimeglumine (Gd)-T1-weighted images (Gd-T1WI), and change in tumor volume. The bone tumors were divided into two groups: group A was comprised of tumors with less than 90% necrosis after treatment and group B of tumors at least with 90%. Changes in ADC value, tumor volume, and CNR were compared between the groups. Change in the ADC value was statistically greater in group B than that in the group A (p=0.003). There was no significant difference in the changes in CNR on T2WI (p=0.683), in CNR on Gd-T1WI (p=0.763), and tumor volume (p=0.065). The ADC value on DWI is a promising tool for monitoring the therapeutic response of primary bone sarcomas.

Prognostic Value of Perfusion MR Imaging of High-Grade Astrocytomas: Long-Term Follow-Up Study

BACKGROUND AND PURPOSE: Although the prognostic value of perfusion MR imaging in various gliomas has been investigated, that in high-grade astrocytomas alone has not been fully evaluated. The purpose of this study was to evaluate retrospectively whether the tumor maximum relative cerebral blood volume (rCBV) on pretreatment perfusion MR imaging is of prognostic value in patients with high-grade astrocytoma. MATERIALS AND METHODS: Between January 1999 and December 2002, 49 patients (30 men, 19 women; age range, 23–76 years) with supratentorial high-grade astrocytoma underwent MR imaging before the inception of treatment. The patient age, sex, symptom duration, neurologic function, mental status, Karnofsky Performance Scale, extent of surgery, histopathologic diagnosis, tumor component enhancement, and maximum rCBV were assessed to identify factors affecting survival. Kaplan-Meier survival curves, the logrank test, and the multivariate Cox proportional hazards model were used to evaluate prognostic factors. RESULTS: The maximum rCBV was significantly higher in the 31 patients with glioblastoma multiforme than in the 18 with anaplastic astrocytoma (P < .03). The 2-year overall survival rate was 67% for 27 patients with a low (≤2.3) and 9% for 22 patients with a high (>2.3) maximum rCBV value (P < .001). Independent important prognostic factors were the histologic diagnosis (hazard ratio = 9.707; 95% confidence interval (CI), 3.163–29.788), maximum rCBV (4.739; 95% CI, 1.950–11.518), extent of surgery (2.692; 95% CI, 1.196–6.061), and sex (2.632; 95% CI, 1.153–6.010). CONCLUSION: The maximum rCBV at pretreatment perfusion MR imaging is a useful clinical prognostic biomarker for survival in patients with high-grade astrocytoma.

Ability of diffusion-weighted imaging for the differential diagnosis between chronic expanding hematomas and malignant soft tissue tumors.

To evaluate the potential of diffusion‐weighted imaging (DWI) in distinguishing chronic expanding hematomas (CEHs) from malignant soft tissue tumors.

Evaluation of diffusion‐weighted imaging for the differential diagnosis of poorly contrast‐enhanced and T2‐prolonged bone masses: Initial experience

To determine whether quantitative diffusion‐weighted imaging (DWI) is useful for characterizing poorly contrast‐enhanced and T2‐prolonged bone masses.

Usefulness of Diffusion-Weighted Imaging in the Localization of Prostate Cancer

PURPOSE Advances in high-precision radiation therapy techniques for patients with prostate cancer permit selective escalation of the radiation dose delivered to the dominant intraprostatic lesion and improve the therapeutic ratio. We evaluated the value of diffusion-weighted imaging (DWI) for dominant intraprostatic lesion assessment. METHODS AND MATERIALS The study population consisted of 23 patients with early prostate cancer. Before undergoing total prostatectomy, they were evaluated by means of magnetic resonance imaging, including DWI. T2-weighted imaging (T2WI) with and without DWI were retrospectively assessed by six independent observers. Imaging findings were compared with pathologic results from whole prostate specimens on a lesion-by-lesion basis. RESULTS Pathologic study identified 43 lesions in 23 patients. On magnetic resonance imaging, the six observers correctly identified 11-22 of 43 lesions (sensitivity, 26-51%) on T2WI alone and 20-31 (sensitivity, 47-72%) on T2WI plus DWI. Positive predictive values were 42-73% on T2WI alone and 58-80% on T2WI plus DWI. For all observers, detection was higher on combined T2WI and DWI than on T2WI alone. CONCLUSION Because the addition of DWI to T2WI improves the detectability of prostate cancer, DWI may offer a promising new approach for radiation therapy planning.

Tomosynthesis of the Wrist and Hand in Patients With Rheumatoid Arthritis: Comparison With Radiography and MRI

OBJECTIVE The purpose of this article is to compare tomosynthesis with radiography and MRI of the wrist and hand for evaluating bone erosion in patients with rheumatoid arthritis (RA). MATERIALS AND METHODS Twenty consecutive patients with an established diagnosis of RA and five control patients were included in this study. They underwent radiography, tomosynthesis, and MRI of the bilateral hand and wrist within a week. The mean total dose of radiography and tomosynthesis was 0.13 and 0.25 mGy, respectively. MRI evaluation was performed according to the Outcome Measures in Rheumatology Clinical Trials recommendations. Bone erosion on images from the three modalities was independently reviewed by two certificated radiologists with a 4-point scale (0, normal; 1, discrete erosion; 2, < 50% of the joint surface; and 3, ≥ 50% of the joint surface). RESULTS The detection rates of bone erosion for radiography, tomosynthesis, and MRI were 26.5%, 36.1%, and 36.7%, respectively. Significantly more bone erosions were revealed with tomosynthesis and MRI than with radiography (p < 0.01). When MRI was used as the reference standard, the sensitivity, specificity, and accuracy were 68.1%, 97.5%, and 86.7%, respectively, for radiography and 94.8%, 97.8%, and 96.7%, respectively, for tomosynthesis. Interobserver agreement (kappa value) for bone erosion was good to excellent on tomosynthesis and MRI for all joints (0.65-1.00 and 0.68-1.00, respectively), whereas it was slight to fair on radiography for some carpal bones and bases of metacarpal bones (0.22-0.56). CONCLUSION Tomosynthesis is superior to radiography and almost comparable to MRI for the detection of bone erosion in patients with RA.

Iterative decomposition of water and fat with echo asymmetry and least‐squares estimation (IDEAL) of the wrist and finger at 3T: Comparison with chemical shift selective fat suppression images

To compare fat‐suppressed magnetic resonance imaging (MRI) quality using iterative decomposition of water and fat with echo asymmetry and least‐squares estimation (IDEAL) with that using chemical shift selective fat‐suppressed T1‐weighted spin‐echo (CHESS) images for evaluating rheumatoid arthritis (RA) lesions of the hand and finger at 3T.

Diagnosis of intracranial hemorrhagic lesions: Comparison between 3D-SWAN (3D T2*-weighted imaging with multi-echo acquisition) and 2D-T2*-weighted imaging

Background 3D-susceptibility-weighted angiography (SWAN) can produce high-resolution images that yield excellent susceptibility-weighted contrast at a relatively short acquisition time. Purpose To compare SWAN- and 2D-T2*-weighted gradient-echo images (T2*-WI) for their sensitivity in the depiction of cerebral hemorrhagic lesions. Material and Methods We subjected 75 patients with suspected cerebral hemorrhagic lesions to SWAN and T2*-WI at 3T. We first measured the contrast-to-noise ratio (CNR) using an agar phantom that contained different concentrations of superparamagnetic iron oxide (SPIO). The acquisition time for SWAN and T2*-WI was similar (182 vs. 196 s). Neuroradiologists compared the two imaging methods for lesion detectability and conspicuity. Results The CNR of the phantom was higher on SWAN images. Of the 75 patients, 50 were found to have a total of 278 cerebral hemorrhagic lesions (microbleeds, n = 229 [82.4%]; intracerebral hemorrhage, n = 18 [6.5%]; superficial siderosis, n = 13 [4.7%]; axonal injuries, n = 8 [2.9%]; subarachnoid hemorrhage [SAH] or brain contusion, n = 3 each [1.0%]; subdural hematoma, n = 2 [0.7%]; cavernous hemangioma or dural arterteriovenous fistula, n = 1 each [0.4%]). In none of the lesions was the SWAN sequence inferior to T2*-WI with respect to lesion detectability and conspicuity. In fact, SWAN yielded better lesion conspicuity in patients with superficial siderosis and SAH: it detected significantly more lesions than T2*-WI (P < 0.01) and it was particularly useful for the detection of microbleeds and lesions near the skull base. Conclusion SWAN is equal or superior to standard T2*-WI for the diagnosis of various cerebral hemorrhagic lesions. Because its acquisition time is reasonable it may replace T2*-WI.

Quantification of bone marrow fat content using iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL): reproducibility, site variation and correlation with age and menopause

OBJECTIVE To determine the reproducibility of the quantitative chemical shift-based water-fat separation method with a multiecho gradient echo sequence [iteraterative decomposition of water and fat with echo asymmetry and least-squares estimation quantitation sequence (IDEAL-IQ)] for assessing bone marrow fat fraction (FF); to evaluate variation of FF at different bone sites; and to investigate its association with age and menopause. METHODS 31 consecutive females who underwent pelvic iterative decomposition of water and fat with echo asymmetry and least-squares estimation at 3-T MRI were included in this study. Quantitative FF using IDEAL-IQ of four bone sites were analyzed. The coefficients of variance (CV) on each site were evaluated repeatedly 10 times to assess the reproducibility. Correlations between FF and age were evaluated on each site, and the FFs between pre- and post-menopausal groups were compared. RESULTS The CV in the quantification of marrow FF ranged from 0.69% to 1.70%. A statistically significant correlation was established between the FF and the age in lumbar vertebral body, ilium and intertrochanteric region of the femur (p < 0.001). The average FF of post-menopausal females was significantly higher than that of pre-menopausal females in these sites (p < 0.05). In the greater trochanter of the femur, there was no significant correlation between FF and age. CONCLUSION In vivo IDEAL-IQ would provide reliable quantification of bone marrow fat. ADVANCES IN KNOWLEDGE IDEAL-IQ is simple to perform in a short time and may be practical for providing information on bone quality in clinical settings.

Gallbladder metastasis from renal cell carcinoma: a case report with review of the literature.

We experienced a rare case of gallbladder metastasis from renal cell carcinoma (RCC). Ultrasound, computed tomographic, and magnetic resonance findings showed a hypervascular polypoid mass and correlated well with histopathologic findings. The mass showed high intensity on diffusion-weighted images, and the apparent diffusion coefficient was relatively low. These imaging findings are considered characteristic and may assist preoperative diagnosis in patients with history of RCC.