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1.
Obes Res Clin Pract ; 17(5): 411-420, 2023.
Article En | MEDLINE | ID: mdl-37679239

Orlistat, an anti-obesity agent, inhibits the metabolism and absorption of dietary fat by inactivating pancreatic lipase in the gut. The effect of orlistat on the gut microbiota of Japanese individuals with obesity is unknown. This study aimed to explore the effects of orlistat on the gut microbiota and fatty acid metabolism of Japanese individuals with obesity. Fourteen subjects with visceral fat obesity (waist circumference ≥85 cm) took orlistat orally at a dose of 60 mg, 3 times a day for 8 weeks. Body weight; waist circumference; visceral fat area; levels of short-chain fatty acids, gut microbiota, fatty acid metabolites in the feces, and gastrointestinal hormones; and adverse events were evaluated. Body weight, waist circumference, and blood leptin concentrations were significantly lower after orlistat treatment (mean ± standard deviation, 77.8 ± 9.1 kg; 91.9 ± 8.7 cm; and 4546 ± 3211 pg/mL, respectively) compared with before treatment (79.4 ± 9.0 kg; 94.4 ± 8.0 cm; and 5881 ± 3526 pg/mL, respectively). Significant increases in fecal levels of fatty acid metabolites (10-hydroxy-cis-12-octadecenoic acid, 10-oxo-cis-12-octadecenoic acid, and 10-oxo-trans-11-octadecenoic acid) were detected. Meanwhile, no significant changes were found in abdominal computed tomography parameters, blood marker levels, or short-chain fatty acid levels in the feces. Gut microbiota analysis revealed that some study subjects had decreased abundance of Firmicutes, increased abundance of Bacteroidetes, and increased α-diversity indices (Chao1 and ACE) after 8 weeks of treatment. The levels of Lactobacillus genus and Lactobacillus gasseri were significantly higher after 8 weeks of treatment. None of the subjects discontinued treatment or experienced severe adverse events. This study suggested that orlistat might alter gut microbiota composition and affect the body through fatty acid metabolites produced by the modified gut bacteria.


Gastrointestinal Microbiome , Humans , Orlistat/pharmacology , Obesity , Body Weight , Fatty Acids , Lipase
2.
J Dermatol ; 49(10): 939-947, 2022 Oct.
Article En | MEDLINE | ID: mdl-35633047

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was declared a pandemic by the World Health Organization, and COVID-19 continues to have a major impact on society. Numerous studies have reported impaired health sequelae after COVID-19 recovery, one of which is hair loss. Individuals with hair loss experience a substantial mental burden, which potentially hinders their social life. However, few studies have systematically analyzed the details including hair loss. Therefore, we conducted a narrative review using PubMed on the frequency, associated comorbidities, disease characteristics, and treatment of hair loss after SARS-CoV-2 infection (HLASCI). Two search strings were used to identify 28 articles. Of note, most of the literature identified on COVID-19 sequelae reported an emergence/occurrence of hair loss. HLASCI is speculated to be composed of a heterogeneous population, with the onset or exacerbation of telogen effluvium (TE), anagen effluvium, androgenetic alopecia (AGA), and alopecia areata (AA) reported as possible underlying mechanisms. Among these, acute TE is thought to be the primary cause of HLASCI, with COVID-19 treatment and TE improvement being considered crucial for HLASCI management. An association between COVID-19 and AA exacerbation has also been implicated with still insufficient evidence. Spontaneous recovery of TE can be expected once infection reduces; however, faster improvement in symptoms is expected to reduce the mental and social burden of patients. An additional search string identified 11 articles about TE treatment which suggested that the use of minoxidil may be beneficial. Topical minoxidil has been widely used for AGA patients, who have been speculated to exhibit poor resistance to SARS-CoV-2. Topical minoxidil may provide relief from HLASCI, but future clinical research is warranted to confirm this observation.


Alopecia Areata , COVID-19 Drug Treatment , COVID-19 , Alopecia/drug therapy , Alopecia/etiology , Alopecia Areata/drug therapy , COVID-19/complications , Humans , Minoxidil/therapeutic use , SARS-CoV-2
4.
Adv Ther ; 36(1): 217-231, 2019 01.
Article En | MEDLINE | ID: mdl-30387022

INTRODUCTION: Orlistat is an inhibitor of pancreatic lipase and is used as an anti-obesity drug in many countries. However, there are no data available regarding the effects of orlistat on visceral fat (VF) accumulation in Japanese individuals. Therefore, this study aimed to analyze the efficacy and safety of 52 weeks of orlistat administration in Japanese individuals. METHODS: Orlistat 60 mg was administered orally three times daily for 52 weeks to Japanese participants with excessive VF accumulation and without dyslipidemia, diabetes mellitus, and hypertension (metabolic diseases). Participants were also counseled to improve their diet and to maintain exercise habits. We defined excessive VF accumulation as a waist circumference (WC) of ≥ 85 cm for males and ≥ 90 cm for females, which corresponds to a VF area of 100 cm2. Adverse reactions, clinical laboratory tests, VF, WC, body weight (BW), etc., were monitored throughout the study period. RESULTS: VF, WC, and BW were significantly reduced at week 52 from baseline; the mean ± standard error rate of change was - 21.52% ± 1.89%, - 4.89% ± 0.45%, and - 5.36% ± 0.56%, respectively, and continued to reduce throughout the 52 weeks; these significantly reduced at whole term compared with baseline. Most adverse reactions were defecation-related symptoms such as oily spotting and flatus with discharge (flatus with small amounts of stool or oil) due to the pharmacologic effects of the lipase inhibitor. These symptoms were mostly mild, reversible, and recognizable by the participants; none were serious or severe. No participants discontinued by medical judgment about adverse reactions, and the drug could be administered continuously. CONCLUSION: VF, WC, and BW were reduced from week 4 to week 52, indicating the effect of long-term orlistat administration. Moreover, it was well tolerated with an acceptable safety profile. Long-term administration of orlistat may be efficacious in reducing VF accumulation with safety when used in combination with diet and exercise. TRIAL REGISTRATION: This study is registered with the Japan Pharmaceutical Information Center (identifier: JapicCTI-184004). FUNDING: Funding for this study was provided by Taisho Pharmaceutical Co., Ltd.


Anti-Obesity Agents/therapeutic use , Intra-Abdominal Fat , Lactones/therapeutic use , Obesity/drug therapy , Orlistat/therapeutic use , Adult , Anthropometry , Body Weight , Female , Humans , Japan , Longitudinal Studies , Male , Middle Aged
5.
Adv Ther ; 36(1): 86-100, 2019 01.
Article En | MEDLINE | ID: mdl-30535651

INTRODUCTION: Orlistat is an inhibitor of pancreatic lipase and is used as an anti-obesity drug in many countries. However, there are no data available regarding the effects of orlistat on visceral fat accumulation in Japanese subjects. Therefore, this comparative, placebo-controlled, double-blind, randomized study aimed to evaluate the efficacy and safety of orlistat in Japanese participants with excessive visceral fat accumulation and without dyslipidemia, diabetes mellitus, and hypertension ("metabolic diseases"). METHODS: The study population included Japanese participants with excessive visceral fat accumulation (waist circumference ≥ 85 cm in males and ≥ 90 cm in females, which corresponds to a visceral fat area of 100 cm2) and without metabolic diseases. Following a 12-week observation term, participants were randomized to the orlistat 60 mg group (n = 100) or placebo group (n = 100). Both drugs were administered orally three times daily for 24 weeks. Participants were also counseled to improve their diet and to maintain exercise throughout the study. Visceral fat area, subcutaneous fat area, waist circumference, body weight, body mass index, adverse reactions, laboratory tests, and blood pressure were regularly assessed. RESULTS: Visceral fat area, waist circumference, and body weight were significantly reduced in the orlistat group (mean ± standard error, - 13.50 ± 1.52%, - 2.51 ± 0.25%, and - 2.79 ± 0.30%, respectively) compared to the placebo group (- 5.45 ± 1.50%, - 1.55 ± 0.26%, and - 1.22 ± 0.28%, respectively) at the last assessment. The main adverse reactions were defecation-related symptoms including oily spotting and flatus with discharge, resulting from the pharmacological effects of orlistat. Most adverse reactions were mild, and none were serious or severe. CONCLUSION: Orlistat administration reduced visceral fat area, waist circumference, and body weight in Japanese participants with excessive visceral fat and without metabolic diseases. In addition, safety was confirmed with a tolerable profile. Orlistat may be useful to reduce excessive visceral fat accumulation when used in combination with diet and exercise. TRIAL REGISTRATION: Japan Pharmaceutical Information Center identifier, JapicCTI-184005. FUNDING: Taisho Pharmaceutical Co., Ltd.


Anti-Obesity Agents/therapeutic use , Exercise , Intra-Abdominal Fat/pathology , Obesity/drug therapy , Adult , Anthropometry , Body Mass Index , Body Weight/drug effects , Combined Modality Therapy , Double-Blind Method , Female , Humans , Japan , Male , Middle Aged , Obesity/therapy , Orlistat , Treatment Outcome
6.
Biosci Biotechnol Biochem ; 81(1): 102-111, 2017 Jan.
Article En | MEDLINE | ID: mdl-27691719

Tricholoma matsutake, a basidiomycete, forms ectomycorrhizas with Pinus densiflora as the host tree. Its fruiting body, "matsutake" in Japanese, is an edible and highly prized mushroom, and it grows in a circle called a fairy ring. Beneath the fairy ring of T. matsutake, a whitish mycelium-soil aggregated zone, called "shiro" in Japanese, develops. The front of the shiro, an active mycorrhizal zone, functions to gather nutrients from the soil and roots to nourish the fairy ring. Bacteria and sporulating fungi decrease from the shiro front, whereas they increase inside and outside the shiro front. Ohara demonstrated that the shiro front exhibited antimicrobial activity, but the antimicrobial substance has remained unidentified for 50 years. We have identified the antimicrobial substance as the (oxalato)aluminate complex, known as a reaction product of oxalic acid and aluminum phosphate to release soluble phosphorus. The complex protects the shiro from micro-organisms, and contributes to its development.


Aluminum/chemistry , Organometallic Compounds/chemistry , Organometallic Compounds/pharmacology , Oxalates/chemistry , Soil Microbiology , Tricholoma/drug effects , Anti-Infective Agents/chemistry , Anti-Infective Agents/isolation & purification , Anti-Infective Agents/pharmacology , Bacteria/drug effects , Fungi/drug effects , Microbial Sensitivity Tests , Organometallic Compounds/isolation & purification
7.
Mycorrhiza ; 26(8): 847-861, 2016 Nov.
Article En | MEDLINE | ID: mdl-27371100

Tricholoma matsutake is an ectomycorrhizal basidiomycete that produces prized, yet uncultivable, "matsutake" mushrooms along densely developed mycelia, called "shiro," in the rhizosphere of coniferous forests. Pinus densiflora is a major host of this fungus in Japan. Measuring T. matsutake biomass in soil allows us to determine the kinetics of fungal growth before and after fruiting, which is useful for analyzing the conditions of the shiro and its surrounding mycorrhizosphere, predicting fruiting timing, and managing forests to obtain better crop yields. Here, we document a novel method to quantify T. matsutake mycelia in soil by quantifying a single-copy DNA element that is uniquely conserved within T. matsutake but is absent from other fungal species, including close relatives and a wide range of ectomycorrhizal associates of P. densiflora. The targeted DNA region was amplified quantitatively in cultured mycelia that were mixed with other fungal species and soil, as well as in an in vitro co-culture system with P. densiflora seedlings. Using this method, we quantified T. matsutake mycelia not only from shiro in natural environments but also from the surrounding soil in which T. matsutake mycelia could not be observed by visual examination or distinguished by other means. It was demonstrated that the core of the shiro and its underlying area in the B horizon are predominantly composed of fungal mycelia. The fungal mass in the A or A0 horizon was much lower, although many white mycelia were observed at the A horizon. Additionally, the rhizospheric fungal biomass peaked during the fruiting season.


DNA, Fungal/genetics , Polymerase Chain Reaction/methods , Tricholoma/physiology , Biomass , Genetic Markers , Genome, Fungal , Kinetics , Mycelium , Sensitivity and Specificity , Serine Endopeptidases , Soil Microbiology , Species Specificity
9.
Ann Nucl Med ; 20(6): 399-408, 2006 Jul.
Article En | MEDLINE | ID: mdl-16922468

UNLABELLED: 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has become widely available and an important oncological technique. To evaluate the influence of PET on detection of bone metastasis, we compared the diagnostic accuracy of PET and conventional bone scintigraphy (BS) in a variety of cancer patients. METHODS: Consecutive ninety-five patients with various cancers, who received both PET and BS within one month, were retrospectively analyzed. A whole-body PET (from face to upper thigh) and a standard whole body BS were performed and these images were interpreted by two experienced nuclear medicine physicians with and without patient information using monitor diagnosis. Each image interpretation was performed according to 8 separate areas (skull, vertebra, upper limbs, sternum and clavicles, scapula, ribs, pelvis, and lower limbs) using a 5-point-scale (0: definitely negative, 1: probably negative, 2: equivocal, 3: probably positive, 4: definitely positive for bone metastasis). RESULTS: Twenty-one of 95 patients (22.1%) with 43 of 760 areas (5.7%) of bone metastases were finally confirmed. In untreated patients, 12 of 14 bone metastasis positive patients were detected by PET, while 9 of 14 were detected by BS. Three cases showed true positive in PET and false negative in BS due to osteolytic type bone metastases. In untreated cases, PET with and without clinical information showed better sensitivity than BS in patient-based diagnosis. For the purpose of treatment effect evaluation, PET showed better results because of its ability in the evaluation of rapid response of tumor cells to chemotherapy. Out of 10 cases of multiple-area metastases, 9 cases included vertebrae. There was only one solitary lesion located outside of FOV of PET scan in the femur, but with clinical information that was no problem for PET diagnosis. CONCLUSION: Diagnostic accuracy of bone metastasis was comparable in PET and BS in the present study. In a usual clinical condition, limited FOV (from face to upper thigh) of PET scan may not be a major drawback in the detection of bone metastases because of the relatively low risk of solitary bone metastasis in skull bone and lower limbs.


Bone Neoplasms/diagnostic imaging , Bone Neoplasms/secondary , Fluorodeoxyglucose F18 , Positron-Emission Tomography/methods , Technetium Tc 99m Medronate/analogs & derivatives , Whole Body Imaging/methods , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Humans , Male , Middle Aged , Radiopharmaceuticals , Reproducibility of Results , Retrospective Studies , Sensitivity and Specificity
11.
Ann Nucl Med ; 18(2): 105-14, 2004 Apr.
Article En | MEDLINE | ID: mdl-15195757

PURPOSE: To evaluate the appropriate post-injection timing for hand-held-gamma-ray-detecting probe (GDP) scanning for the intraoperative detection of malignancy after preoperative F-18 FDG (FDG) injection. METHODS: Patient study with superficially located cancer was performed on three patients before operation by dual-phase whole-body PET at 2 and 6-7 hr post-injection of FDG (370 MBq), and by probe scanning from the skin at several points at 1, 3, 5, and 7 hr after FDG injection. TNRa (tumor-adjacent-normal ratio) and TNRc (tumor-contralateral-normal ratio) were calculated. Phantom study was also performed to determine basic GDP function. RESULTS: The patient study revealed that tumors showed constant TNRa (0.9-1.3) and TNRc (1.1-3.0) by GDP count rate, and that there was no tendency of an increase in TNRa with time. The standard deviations of GDP count rate were lower at 1-3 hr post-injection compared with those of delayed scans. While delayed PET showed an increase or no change in the tumor FDG uptake, the decrease of normal tissue FDG uptake was not adequate to create higher TNRs. The phantom study revealed that LN model showed TNRa of 1.7 or greater by GDP count rate (cps) when background contained no FDG, but that they showed TNRa of 1.3 or less when the background contained 4% of the LN FDG activity per ml. CONCLUSION: The present study suggests that higher FDG count rate of tumors at 1-3 hr postinjection would be more suitable for the gamma-probe detection compared with lower count rate at 6-7 hr delayed scans with wide standard deviations.


Breast Neoplasms/diagnostic imaging , Fluorodeoxyglucose F18/administration & dosage , Image Enhancement/methods , Positron-Emission Tomography/methods , Stomach Neoplasms/diagnostic imaging , Surgery, Computer-Assisted/methods , Adult , Aged , Aged, 80 and over , Female , Gamma Cameras , Humans , Injections, Intravenous/methods , Intraoperative Care/methods , Middle Aged , Phantoms, Imaging , Pilot Projects , Positron-Emission Tomography/instrumentation , Preoperative Care/methods , Radiopharmaceuticals/pharmacokinetics , Reproducibility of Results , Sensitivity and Specificity , Time Factors
12.
Nihon Hoshasen Gijutsu Gakkai Zasshi ; 60(4): 491-9, 2004 Apr.
Article Ja | MEDLINE | ID: mdl-15159667

In positron emission tomography (PET), the large number of lines of responses in three-dimensional (3D) acquisition mode creates a high volume of sinogram data and increases reconstruction time in iterative reconstruction. We tried to decrease sinogram data volume by reducing the number of views using angular compression and then evaluated the accuracy of this mashed mode. Three methods were compared, conventional mode (CONV), X2 mashed mode (X2: two adjacent projection angles are added together), and X4 mashed mode (X4: four adjacent angles added). A point source of (18)F was used to measure spatial resolution. A hot spot phantom made of 6 hot spheres (10-38 mm in diameter) within water of 20 cm in diameter was scanned to evaluate the recovery coefficient (RC). A lung-heart-liver phantom made of homogeneous radioactive myocardium, a spherical hot mass in the lung (10 mm in diameter), and background activity in the liver was scanned to evaluate the homogeneity of the myocardial wall. The quality of the reconstructed images was evaluated in terms of the normalized mean square error (NMSE), Bull's eye map, profile curve, and peak value of the spherical hot mass. The reconstruction times of X2 and X4 were one-half and one-quarter, respectively, of that of CONV. In terms of spatial resolution, FWHM of CONV, X2, and X4 were, 4.26, 4.33, and 4.48 (mm) at the center, 4.81, 5.68, and 8.73 tangentially, and 8.01, 8.19, and 8.27 radially at R=200 mm, respectively. RC was similar for all methods. The NMSE values of X2 and X4 compared with CONV were 0.0003 and 0.0014, respectively. In the hot mass, these methods showed almost the same profile curves, although the peak value of X4 was only -1.95% less than that of CONV. Although the result of spatial resolution of X4 was slightly degraded, image quality and physical performance were good. Therefore, the X4 mashed mode used with angular compression was considered clinically useful.


Image Processing, Computer-Assisted/methods , Tomography, Emission-Computed/methods , Humans , Image Processing, Computer-Assisted/instrumentation , Imaging, Three-Dimensional/instrumentation , Phantoms, Imaging , Sensitivity and Specificity , Time Factors , Tomography, Emission-Computed/instrumentation
13.
Ann Nucl Med ; 17(3): 197-203, 2003 May.
Article En | MEDLINE | ID: mdl-12846541

OBJECTIVE: The clinical usefulness of FDG-PET in the follow up of post-operative patients with endometrial cancer was retrospectively evaluated. METHODS: Twenty-one post-operative patients with endometrial cancer received 30 FDG-PET examinations to evaluate recurrence or response to treatment. The findings of FDG-PET were compared with their serum levels of tumor markers, CT and/or MRI findings, and the final outcome. Results of FDG-PET were also correlated with the clinical course of each patient. RESULTS: In detecting recurrent lesions and evaluating treatment responses, FDG-PET, with the help in anatomic information by CT/MRI, showed better diagnostic ability (sensitivity 100.0%, specificity 88.2%, accuracy 93.3%) compared with combined conventional imaging (sensitivity 84.6%, specificity 85.7%, accuracy 85.0%) and tumor markers (sensitivity 100.0%, specificity 70.6%, accuracy 83.3%). FDG-PET had no false-negative results, suggesting the possibility of its use as the first-line examination in a patient's follow-up. FDG-PET could detect unknown lesions in 4 cases, and, as reported for other malignancies, FDG-PET affected the patient management in one-third of the cases. Furthermore, the results of FDG-PET correlated well with the clinical outcome of the patients, with patients with negative PET results tending to show disease-free courses. CONCLUSIONS: These results suggest that, despite the limited number of patients studied, FDG-PET was accurate in detecting recurrence and evaluating therapeutic response, and could afford important information in the management of post-operative patients with endometrial cancer. FDG-PET also appeared to have a possibility to predict the outcome of each patient.


Endometrial Neoplasms/diagnostic imaging , Endometrial Neoplasms/surgery , Fluorodeoxyglucose F18 , Neoplasm Recurrence, Local/diagnostic imaging , Postoperative Care/methods , Tomography, Emission-Computed/methods , Adult , Aged , Aged, 80 and over , Disease-Free Survival , Endometrial Neoplasms/diagnosis , Female , Follow-Up Studies , Humans , Middle Aged , Neoplasm Recurrence, Local/diagnosis , Prognosis , Radiopharmaceuticals , Reproducibility of Results , Retrospective Studies , Sensitivity and Specificity , Treatment Outcome
14.
Ann Nutr Metab ; 47(3-4): 165-9, 2003.
Article En | MEDLINE | ID: mdl-12743469

BACKGROUND: Pipecolic acid, a metabolite of lysine, is found in human physiological fluids and is thought to play an important role in the central inhibitory gamma-aminobutyric acid system. However, it is unclear whether plasma D- and L-pipecolic acid originate from oral food intake or intestinal bacterial metabolites. METHODS: We analyzed the contents of D- and L-pipecolic acid in several processed foods including dairy products (cow's milk, cheese and yogurt), fermented beverages (beer and wine) and heated samples (beef, bovine liver, bread and tofu) to clarify the relationship between plasma D- and L-pipecolic acid and dietary foods. RESULTS: Our study revealed that some of the samples contained high concentrations of total pipecolic acid, and a higher proportion of L- than D-isomers. The other samples also showed high proportions of L-pipecolic acid. It was also shown that there is no significant change in the ratio of the D-isomer before and after heat treatment. The heat treatments could not cause the racemization of pipecolic acid in this study. CONCLUSION: These findings suggest that plasma pipecolic acid, particularly the D-isomer, does not originate from direct food intake and that D- and L-pipecolic acid can possibly be derived from intestinal bacterial metabolites.


Food Analysis , Pipecolic Acids/analysis , Alcoholic Beverages/analysis , Animals , Bread/analysis , Cattle , Chromatography, High Pressure Liquid , Dairy Products/analysis , Hot Temperature , Meat/analysis , Vegetables/chemistry
15.
Ann Nucl Med ; 16(4): 279-87, 2002 Jun.
Article En | MEDLINE | ID: mdl-12126098

This study was done retrospectively to analyze the ultrasonographic (US) findings in thyroid scintigraphic hot areas (HA). Three-thousand, eight-hundred and thirty-nine consecutive patients who underwent 99mTc-pertechnetate (n = 3435) or 123I (n = 457) scintigraphy were analyzed. HA were regarded as present when the tracer concentration was greater than the remaining thyroid tissue, or when hemilobar uptake was observed. High-resolution US examinations were performed with a real-time electronic linear scanner with a 7.5 or 10 MHz transducer. One hundred and four (2.7%) were found to be scintigraphic HA (n = 120). US revealed a nodular lesion or well-demarcated thyroid tissue corresponding to the HA in 94 areas (78.4%, Category 1), an ill-defined region with different echogenicity in 13 areas (10.8%, Category 2), and no correlating lesion in 13 areas (10.8%, Category 3). These 104 patients included 43 with adenomatous goiter (59 areas), 33 with adenoma, 11 with Hashimoto's thyroiditis, 5 with primary thyroid cancer, 4 with euthyroid ophthalmic Graves' disease (EOG), 3 with hemilobar atrophy or hypogenesis, 2 with hemilobar agenesis, 2 with hypothyroidism with blocking-type TSH-receptor antibodies (TSHRAb), I with acute suppurative thyroiditis. Among the 59 adenomatous nodules and 33 adenomas, 51 (86.4%) and 32 (97.0%), respectively, belonged to Category 1. A solitary toxic nodule was significantly larger and occurs more often in older patients than in younger patients. On the other hand, all 17 patients with known autoimmune thyroid diseases including Hashimoto's thyroiditis, EOG and hypothyroidism with blocking TSHRAb belonged to Category 2 or 3. Possible underlying mechanisms are 1) hyperfunctioning tumors or nodules, 2) localized functioning thyroid tissue freed from autoimmune destruction, inflammation or tumor invasion, 3) congenital abnormality, 4) clusters of hyperactive follicular cells caused by long-term TSH and/or TSHRAb stimulation, 5) asymmetry, etc. Scintigraphic HA are observed in patients with various thyroid diseases and high-resolution US appears to be helpful clinically for the differential diagnosis of the above mentioned disorders.


Sodium Pertechnetate Tc 99m , Thyroid Diseases/diagnostic imaging , Adolescent , Adult , Aged , Aged, 80 and over , Child , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Radionuclide Imaging , Radiopharmaceuticals/pharmacokinetics , Retrospective Studies , Sensitivity and Specificity , Single-Blind Method , Sodium Pertechnetate Tc 99m/pharmacokinetics , Thyroid Diseases/metabolism , Thyroid Gland/diagnostic imaging , Thyroid Gland/metabolism , Ultrasonography
16.
Nihon Hoshasen Gijutsu Gakkai Zasshi ; 58(5): 670-8, 2002 May.
Article Ja | MEDLINE | ID: mdl-12520237

Maximum likelihood expectation maximization (ML-EM) image quality is sensitive to the number of iterations, because a large number of iterations leads to images with checkerboard noise. The use of median filtering in the reconstruction process allows both noise reduction and edge preservation. We examined the value of median filtering after reconstruction with ML-EM by comparing filtered back projection (FBP) with a ramp filter or ML-EM without filtering. SPECT images were obtained with a dual-head gamma camera. The acquisition time was changed from 10 to 200 (seconds/frame) to examine the effect of the count statistics on the quality of the reconstructed images. First, images were reconstructed with ML-EM by changing the number of iterations from 1 to 150 in each study. Additionally, median filtering was applied following reconstruction with ML-EM. The quality of the reconstructed images was evaluated in terms of normalized mean square error (NMSE) values and two-dimensional power spectrum analysis. Median filtering after reconstruction by the ML-EM method provided stable NMSE values even when the number of iterations was increased. The signal element of the image was close to the reference image for any repetition number of iterations. Median filtering after reconstruction with ML-EM was useful in reducing noise, with a similar resolution achieved by reconstruction with FBP and a ramp filter. Especially in images with poor count statistics, median filtering after reconstruction with ML-EM is effective as a simple, widely available method.


Image Enhancement/methods , Image Processing, Computer-Assisted/methods , Tomography, Emission-Computed, Single-Photon/methods , Filtration , Phantoms, Imaging , Tomography, Emission-Computed, Single-Photon/instrumentation
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