Katsuhito Yamasaki

Refraction-enhanced x-ray imaging of mouse lung using synchrotron radiation source.

The low divergent x-ray beam from the third-generation synchrotron radiation source such as SPring-8 enables us to observe refraction of x rays that is in the range of microradians. Under an experimental condition for which ray optics is a good approximation, we found that the refraction produces a high-contrast projection image of a mouse when it was recorded at 6.5 m behind the specimen. Especially, the lung is visualized far better than with the conventional imaging which utilizes absorption of x rays. This is a promising new technique for the diagnosis of diseases in the human lung with a low radiation dose.

Attempt at Visualizing Breast Cancer with X-ray Dark Field Imaging

X-ray dark-field imaging (DFI) can clearly visualize breast cancer phantoms and cancer cell nests, stroma, fat tissue, ductus lactiferi, muscle, collagen fibers at stroma and calcification in a 2.8-mm-thick breast cancer pathological specimen. The system comprises a Bragg asymmetric-cut monochro-collimator and a 2.124-mm-thick Si 440 Laue diffraction analyzer at 35 keV. Both optical elements are Floating Zone made silicon crystals. The view size of 33 mm (H) ×19.5 mm (V) and the spatial resolution of 10 µm or better are obtainable at the vertical wiggler beamline BL14B at the Photon Factory.

3-D reconstruction and virtual ductoscopy of high-grade ductal carcinoma in situ of the breast with casting type calcifications using refraction-based X-ray CT

Stereomicroscopic observations of thick sections, or three-dimensional (3-D) reconstructions from serial sections, have provided insights into histopathology. However, they generally require time-consuming and laborious procedures. Recently, we have developed a new algorithm for refraction-based X-ray computed tomography (CT). The aim of this study is to apply this emerging technology to visualize the 3-D structure of a high-grade ductal carcinomas in situ (DCIS) of the breast. The high-resolution two-dimensional images of the refraction-based CT were validated by comparing them with the sequential histological sections. Without adding any contrast medium, the new CT showed strong contrast and was able to depict the non-calcified fine structures such as duct walls and intraductal carcinoma itself, both of which were barely visible in a conventional absorption-based CT. 3-D reconstruction and virtual endoscopy revealed that the high-grade DCIS was located within the dichotomatous branches of the ducts. Multiple calcifications occurred in the necrotic core of the continuous DCIS, resulting in linear and branching (casting type) calcifications, a hallmark of high-grade DCIS on mammograms. In conclusion, refraction-based X-ray CT approaches the low-power light microscopic view of the histological sections. It provides high quality slice data for 3-D reconstruction and virtual ductosocpy.

Association between diastolic blood pressure and lower hemoglobin A1C and frontal brain atrophy in elderly subjects with diabetes mellitus

ropathy also affect the enteric nervous system. Visceral enteric neuropathies are probably common in nursing home residents and are manifested by tertiary contractions of the esophagus and diabetic gastroparesis. A review of the labeling information provided in the 2006 Physician’s Desk Reference for nongeneric antimuscarinic drugs used for overactive bladder indicates that these agents are contraindicated in the presence of gastric retention. In addition, the presence of decreased gastrointestinal motility is listed as a precaution. Clinicians seldom study or quantitate gastrointestinal motility. The labeling of oxybutynin specifically recommends cautious use in the presence of gastroesophageal reflux disease. The percentage of subjects who experienced dyspepsia is listed as being from 0.9% to 5.8% greater than placebo. Trospium is considered to be an ‘‘antispasmodic’’ and has been shown to delay gastric emptying and to increase reflux (i.e., the fractional time of esophageal pHo4) in healthy subjects. Regurgitated aspirated material (food, acid, or particulate material) may produce wheezing or ‘‘bronchitis,’’ or a chemical pneumonitis, and may produce pulmonary infection if the aspirated material is colonized with bacteria. Proton pump inhibitor-induced hypochlorhydria or gastric stasis facilitate gastric colonization. The use of gastric acid–suppressive drugs is a risk factor for community-acquired pneumonia. Macro-aspiration episodes caused by gastric regurgitation often have an acute onset and may be associated with postprandial or recumbent ‘‘emesis’’ or gastric material on the cheek, pillow, or clothing. I believe that these episodes are relatively common and that most physicians fail to appreciate this mechanism. Aspiration that occurs in the recumbent position produces infiltrates located in the midlung fields, including the posterior segment of the upper lobe and apical segments of the lower lobes. One study supports the possibility that many cases of aspiration ‘‘pneumonia’’ may be related to aspiration of food, acid, or particulate material without infection. Protected bronchoalveolar lavage specimens were obtained within 4 hours of any antibiotic administration from 95 intubated residents admitted directly from a nursing home to an intensive care unit with risk factors for pharyngeal aspiration or reflux. In 41 of 95, clinicians failed to isolate bacteria during bronchoalveolar lavage, suggesting the presence of nonbacterial ‘‘pneumonitis.’’ Reflux and regurgitation are also an acknowledged cause of asthmatic bronchitis and chronic cough. In one study, aspiration pneumonia accounted for more than one-third of deaths attributed to gastroesophageal reflux disease. It is unclear how often antimuscarinic drugs lead to pulmonary aspiration events, but in the frail elderly, I believe that this potentially lethal possibility deserves the same level of concern as that given to cognitive dysfunction.

Sharper image of breast cancer cells and stroma in dense breast using thinner angular filter under X-ray dark-field imaging

The visibility of breast cancer was studied by two types of Laue angular filter (LAF) under x-ray dark field imaging. One was designed so that a field size of 90 ×90 mm2 was available by a 2.124-mm-thick LAF with a 35 keV x-ray energy. The second was a thin LAF of 125.6 µm thickness with a view field of 10 ×10 mm2 using a 13.7 keV x-ray. The estimated spatial resolutions for the cases of the 2.124-mm-thick LAF and the 125.6-µm-thick LAF were 139 and 23 µm, respectively. This is in good agreement with our experiment.

Attempt at Two-Dimensional Mapping of X-ray Fluorescence from Breast Cancer Tissue

A world first two-dimensional mapping of X-ray fluorescence from an invasive papillary carcinoma containing three kinds of metal elements that by white radiation has been obtained. Carcinoma shows intense Ca K X-rays, while normal tissue including stroma, shows no such Ca X-ray signals within experimental precision, but even shows reasonable Fe and Zn K X-ray intensity. This has extremely good correspondence to an X-ray dark-field (X-DF) image taken using a Laue angular analyzer. This fact may suggest an idea that carcinoma may attract Ca atoms better than Fe and Zn atoms, which are involved more in normal tissue.

Hemodynamic Evaluation of Left Testicular Varicocele by Scrotal Scintigraphy

Objective: Scintigraphically assessed hemodynamics of left testicular varicoceles were correlated with spermatogenesis and the effect of varicocelectomy. Methods: Comparison of the time–activity curve (TAC) of the left hemiscrotum with those of the femoral artery and femoral muscle identified three types of scrotal TAC:TAC–1 peaked as rapidly as in the femoral artery; TAC–3, as slowly as in femoral muscle, and TAC–2, intermediate between these. Comparison of TAC of the left hemiscrotum before and after varicocelectomy was done. Testicular biopsy specimens and the effect of varicocelectomy on semen analyses were compared between the types of TAC. Results: 60 patients were divided into 3 groups: 17 in TAC–1; 13 in TAC–2, and 30 in TAC–3. The TAC of the left scrotum showed the same TAC pattern as the left femoral muscle in each patient after varicocelectomy. Spermatogenesis deteriorated most in biopsy specimens from TAC–2 patients. Semen analysis showed improved total motile sperm counts in 58.8, 69.2 and 26.7% of TAC–1, TAC–2, and TAC–3 patients, respectively. Conclusions: TAC–1 and TAC–2 patients were better candidates for varicocelectomy than TAC–3 patients. The hemodynamics of the internal spermatic veins and pampiniform plexus in TAC–3 patients might be different from those in TAC–1 and TAC–2 patients.

Refraction Imaging and Histologic Correlation in Excised Tissue from a Normal Human Lung: Preliminary Report

RATIONALE AND OBJECTIVES The authors performed this study to evaluate the spatial resolution of refraction imaging performed with synchrotron radiation (SR) on 2-mm-thick sections of excised normal human lung. MATERIALS AND METHODS Refraction images of specimens from a normal human lung were obtained with 19 keV, a 5-second exposure time, and a 2.4 x 2.4-cm field of view. The specimen-detector distance was 83 cm. RESULTS Structures of secondary pulmonary lobule consisting of pulmonary arteriole, terminal bronchiole, air sac, and venules in the interlobular septum in normal lung were clearly illustrated on refraction images obtained with SR. The imaging findings showed good correlation with those from histologic examination. The spatial resolution of the refraction images was approximately 10-30 microm, as measured with light microscopic analysis of specimens stained with hematoxylin-eosin. CONCLUSION With refinement, this technique may have some practical purpose for diagnosing lung disease in vivo.

X-ray refraction-contrast imaging using synchrotron radiation at SPring-8

An edge-enhanced imaging technique using the X-ray refraction effect for high contrast outline imaging have been investigated using a third generation of synchrotron radiation source. This technique can be applied to imaging of soft tissues that can not be imaged by conventional absorption- contrast imaging. We have attempted to apply this method to accurate diagnosis of the lung cancer with reduced absorbed dose. In preliminary experiments, we took images of a glass capillary tube and a nude mouse with a long object-to-detector distance using monochromatized X-ray and a high-spatial- resolution CCD-based image detector. Compared to conventional absorption-contrast images, the image contrast is enhanced at an interface between two materials by the X-ray refraction. In a chest image of the mouse, outline images of the alveoli, the bronchi and the trachea were visualized with higher contrast than that of the ribs. It may be effective for early detection of small lung cancer lesions.

Potential use of a 100-mm film digitizer and image processor for film archiving.

The present study was undertaken to examine experimentally and clinically whether a 100-mm roll-film digitizer and image processing device could preserve or increase the diagnostic accuracy of 100-mm roll films used in the mass screening of patients for lung cancer and provide picture archives of high enough image quality to replace the original films. The quality of the processed digitized CRT image was found to be only slightly less than that of the original films. There was only a slight decrease in diagnostic accuracy, and the system was judged to be potentially useful as a miniature picture archiving and reference system.