Kiyohisa Nagai

Age-related and zonal anatomical changes of apparent diffusion coefficient values in normal human prostatic tissues.

To identify age‐related changes and differences in the diffusion of water molecules within the prostate, through diffusion‐weighted imaging (DWI) of the prostate gland in healthy adult Japanese men.

Detection of bone marrow and extramedullary involvement in patients with non-Hodgkin’s lymphoma by whole-body MRI: comparison with bone and 67Ga scintigraphies

The aim of this study was to evaluate the diagnostic potential of whole-body MRI (WB-MRI) for the detection of bone marrow and extramedullary involvement in patients with non-Hodgkin’s lymphoma. WB-MRI, which was performed on 34 patients, consisted of the recording of T1-weighted spin-echo images and a fast STIR sequence covering the entire skeleton. The WB-MRI findings for bone marrow and extramedullary involvement were compared with those from 67Ga and bone scintigraphies and bone marrow biopsy results. Two MRI specialists reviewed the WB-MRI results and two expert radiologists in the field of nuclear medicine reviewed the bone and 67Ga scintigraphy findings. Bone marrow and extramedullary involvement of non-Hodgkin’s lymphoma were confirmed by follow-up radiographs and CT and/or a histological biopsy. The detection rate of WB-MRI was high. More bone marrow involvement was detected by biopsy, and more lesions were detected by scintigraphies. In total, 89 lesions were detected by WB-MRI, whereas 15 were found by biopsy, 5 by 67Ga scintigraphy, and 14 by bone scintigraphy. WB-MRI could also detect more extramedullary lesions than 67Ga scintigraphy; i.e., 72 lesions were detected by WB-MRI, whereas 54 were discovered by 67Ga scintigraphy. WB-MRI is useful for evaluating the involvement of bone marrow and extramedullary lesions throughout the skeleton in patients with non-Hodgkin’s lymphoma.

T2-weighted MR imaging of prostate cancer: multishot echo-planar imaging vs fast spin-echo imaging

The aim of the present study was to assess the performance of pre-biopsy T2-weighted MR imaging using multishot echo-planar imaging (EPI) sequence for visualization of prostate cancer and to compare image quality with that of fast spin-echo (FSE) sequence. Thirty-nine patients with suspected prostate cancer and one healthy male volunteer were examined on a 1.5-T MR scanner equipped with a pelvic phased-array coil. Axial MR images were obtained using multishot EPI sequence with a multishot number of 16 and FSE sequence without fat suppression. Paired EPI and FSE images were independently evaluated by three radiologists. Furthermore, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were compared between EPI and FSE images of 12 pathologically proven lesions of prostate cancer. Delineation of the periprostatic venous plexus, prostate zonal anatomy, and seminal vesicle on EPI was graded to be superior/inferior to FSE in 15.8/0, 14.6/0, and 21.5/4.3% of cases, respectively. On the other hand, delineation of the neurovascular bundle was superior/inferior to FSE in 2.6/13.2% of cases. The SNR and CNR of prostate cancer on EPI were significantly higher than those on FSE (7.99±2.51 vs 3.36±0.58, p<0.0001, and 5.51±2.02 vs 2.21±0.79, p<0.0001, respectively). In conclusion, multishot EPI has higher quality of contrast resolution for imaging of prostate cancer compared with FSE and would have the potential usefulness in the detection of prostate cancer, although these results obtained with a phased-array coil cannot be extrapolated to examinations performed with an endorectal coil.

Usefulness of bone imaging in diagnosis of sternocostoclavicular hyperostosis.

Four Patients with sternocostoclavicular hyperostosis showing characteristic abnormal uptake on bone imageing are described Bone imaging was useful in the diagnosis of sternocostoclavicular hyperostosis.

Iodine-131 uptake in a patient with thyroid cancer and rheumatoid arthritis during acupuncture treatment

A patient with thyroid carcinoma had abnormal accumulation of I-131 in the areas of both feet and hands on whole body scan. The sites of abnormal accumulation of I-131 were similar to those on bone scintigraphy. The radiographic examination of the lesions showed characteristic findings of rheumatoid arthritis, and the presence of small gold needles for acupuncture treatment was demonstrated. There were no findings of bone metastases. Although the mechanism of accumulation of I-131 in this patient is unknown, interpreters of I-131 whole body scintigraphs should keep this case in mind when acupuncture treatment has been done. The authors can only speculate on a common blood flow mechanism for enhanced HMDP and I-131 uptake in this arthritic patient who had been treated by acupuncture.

Visualization of soft tissue by technetium-99m MDP in polymyositis : case reports

Two patients with polymyositis showed abnormal muscular uptake of Tc-99m-methylene diphosphonate (MOP) during routine bone imaging. Imaging with Tc-99m MDP is a uselul tool in monitoring the activity of the diseased muscle.

Accumulation of99mTc-HM-PAO in photon deficient areas in bone scan of bone metastasis from hepatocellular carcinoma

To evaluate bone metastasis from hepatocellular carcinoma (HCC), both bone and99mTc-HM-PAO scintigraphies were performed in six patients with clinically and pathologically confirmed HCC. Two patients had a bone scintigram which revealed abnormal accumulation in the skull base, pelvic bone and thoracic spine. The99mTc-HM-PAO scans of both these patients also showed abnormal accumulation in the same sites. The bone scintigrams in one patient revealed not only abnormal accumulation in the ribs but also photon deficient areas in the sternum, thoracic spine and femur, while99mTc-HM-PAO scans showed abnormal accumulation in all these sites. In three patients, bone scintigraphy revealed photon deficient areas in the ribs, pelvic bone and femur, and their99mTc-HM-PAO scintigrams showed abnormal accumulation in the same sites. Thus, it was shown that, in the detection of bone metastasis from HCC by means of bone scintigraphy, it was necessary to pay attention to hot and cold lesions, and that a combination study with99mTc-phosphorous compounds and99mTc-HM-PAO was useful in evaluating these lesions.

The Present State and Future Prospects for Bone Mass Measurement

Many bone measurement techniques have been developed and used in the early detection of bone loss, the prediction of fracture, and the monitoring of therapeutical responses in osteoporosis. Each technique has its own principle and fundamental features such as the site of measurement (e.g., appendicular or axial bone), precision, accuracy, spatial resolution, data-acquisition time, and radiation dose. Each also differs in its performance in the clinical practice of osteoporosis. The purpose of this chapter is to review the present state and future prospects for the use of bone mass measurements clinically.

Chronological changes of3H-1,25(OH)2D3 in tissue and serum after consecutive oral doses of active vitamin D in rats : Comparative study of 1αOHD3 and 1,25(OH)2D3

To determine the effect of consecutive oral administration of 1αOHD3 or 1,25(OH)2D3 on the metabolism of 1,25(OH)2D3, seven-month-old female rats were given 1αOHD3 (0.4 µg/kg/day) or 1,25(OH)2D3 (0.2 µg/kg/day) for 14 days. After the oral administration of 2 μCi of3H-1αOHD3 or3H-1,25(OH)2D3, the rats were sacrificed at 2,6 or 24 h, and the distribution of these tracers and their metabolites in the serum, intestines, liver, kidneys and bone were studied. The consecutive treatment with 1,25(OH)2D3 or 1αOHD3 did not basically alter the elution patterns of3H labeled metabolites on HPLC. The tissue levels of3H-1,25(OH)2D3, administered or converted from3H-1αOHD3, were lower in the treated rats than those in the controls at 24 h, indicating the accelerated disappearance of 3H-1,25 (OH)2D3 following the treatment with 1αOHD3 or 1,25(OH)2D3. The degree of acceleration, however, was less following the treatment with 1αOHD3 than that after treatment with 1,25(OH)2D3. The degree ofacceleration, however, was less following the treatment with 1αOHD3 than that after treatment with 1,25(OH)2D3. This finding might indicate that, when 1αOHD3 or 1,25(OH)2D3 is consecutively administered, the 1,25(OH)2D3 converted from 1αOHD3 by the liver remains longer in the tissues including bone than 1,25(OH)2D3 absorbed directly from the intestine.