Soon-Ah Park

F-18 FDG PET/CT evaluation of sacrococcygeal chordoma.

Chordoma is a rare malignant bone tumor derived from notochordal rests, and the most common site is the sacrococcygeal region. A 52-year-old woman presented with a sacrococcygeal chordoma detected on F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT). The F-18 FDG PET/CT showed a large destructive mass that arose anteriorly in the sacrococcygeal region and heterogeneously increased FDG uptake within the mass was observed. After surgery, histology confirmed the presence of a sacrococcygeal chordoma. The physician should take chordoma into consideration if there is a large osteolytic mass with hypermetabolism in the sacral region on FDG PET/CT.

Detecting the Recurrence of Gastric Cancer after Curative Resection: Comparison of FDG PET/CT and Contrast-Enhanced Abdominal CT

The purpose of this study was to evaluate the value of fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) for detecting the recurrence of gastric cancer. We performed a retrospective review of 139 consecutive patients who underwent PET/CT and contrast-enhanced abdominal CT (CECT) for surveillance of gastric cancer after curative resection. Recurrence of gastric cancer was validated by histopathologic examination for local recurrence or serial imaging study follow-up with at least 1 yr interval for recurrence of distant metastasis form. Twenty-eight patients (20.1%) were confirmed as recurrence. On the patient based analysis, there was no statistically significant difference in the sensitivity, specificity and accuracy of PET/CT (53.6%, 84.7%, and 78.4%, respectively) and those of CECT (64.3%, 86.5%, and 82.0%, respectively) for detecting tumor recurrence except in detection of peritoneal carcinomatosis. Among 36 recurrent lesions, 8 lesions (22.2%) were detected only on PET/CT, and 10 lesions (27.8%) only on CECT. PET/CT had detected secondary malignancy in 8 patients. PET/CT is as accurate as CECT in detection of gastric cancer recurrence after curative resection, excepting detection of peritoneal carcinomatosis. Moreover, additional PET/CT on CECT could improve detection rate of tumor recurrence and provide other critical information such as unexpected secondary malignancy.

The efficacy of dual time point F-18 FDG PET imaging for grading of brain tumors.

Purpose: Several studies have explored the usefulness of dual time point F-18 FDG positron emission tomography imaging (DTPI) in improving detection of brain metastases and tumors outside the brain, distinguishing malignant from benign. In the same manner, DTPI may show better performance to grade of brain tumors. Methods: Twenty-two lesions of 18 consecutive patients with primary or metastatic brain tumor were included prospectively. DTPI was performed and analyzed using maximum standardized uptake values (SUVmax), mean standardized uptake values within isocontour at 70% of maximum pixel values (SUViso), and retention index (RI) for each lesion. Results: SUVmax and SUViso of the delayed image were more efficient than those of early images to classify lesions by the grade of tumors. The RI of SUVmax and SUViso were not significant to classify lesions. Conclusion: DTPI may be a better imaging method to grade the brain tumor than early imaging only.

Patterns of three-phase bone scintigraphy according to the time course of complex regional pain syndrome type I after a stroke or traumatic brain injury.

We have proposed to evaluate different patterns represented on 3-phase bone scintigraphy (TPBS) according to the time course of complex regional pain syndrome (CRPS) type I (CRPS-I) after a stroke or traumatic brain injury. TPBS was performed in 50 consecutive patients for the evaluation of CRPS. We divided the patients into CRPS and non-CPRS groups based on the use of International Association for the Study of Pain criteria. We evaluated the changes on TPBS according to clinical stages based on time course. In the early acute stage within 6 weeks, minimal uptake on all TPBS phases was observed in the 90% of the patients in the CRPS-I group and in 75% of the patients in the non-CRPS group. In the acute stage of CRPS in the range of 2 to 20 weeks, moderately increased uptake was seen for 78%, 83%, and 83% of the patients in the CRPS group for the 3 phases, respectively. However, only 16% of the patients in the non-CRPS group had moderately increased uptake as seen on all TPBS phases. In the late stage of more than 21 weeks, there was no distinct difference in uptake between the 2 groups. A sequential change during the time course for the CPRS-I group was statistically significant (P < 0.05). Therefore, performance of follow-up TPBS may be useful to diagnose CPRS-I in uncertain cases of the early acute stage after a stroke or traumatic brain injury.

Chronic Administration of Monosodium Glutamate under Chronic Variable Stress Impaired Hypothalamic-Pituitary-Adrenal Axis Function in Rats

The hypothalamic-pituitary-adrenal (HPA) axis is the primary endocrine system to respond to stress. The HPA axis may be affected by increased level of corticotrophin-releasing factors under chronic stress and by chronic administration of monosodium glutamate (MSG). The purpose of this study was to investigate whether chronic MSG administration aggravates chronic variable stress (CVS)-induced behavioral and hormonal changes. Twenty-four adult male Sprague-Dawley rats, weighing 200~220 g, were divided into 4 groups as follows: water administration (CON), MSG (3 g/kg) administration (MSG), CVS, and CVS with MSG (3 g/kg) administration (CVS+MSG). In addition, for the purpose of comparing the effect on plasma corticosterone levels between chronic stress and daily care or acute stress, 2 groups were added at the end of the experiment; the 2 new groups were as follows: naïve mice (n=7) and mice exposed to restraint stress for 2 h just before decapitation (A-Str, n=7). In an open field test performed after the experiment, the CVS+MSG group significant decrease in activity. The increase in relative adrenal weights in the CVS and CVS+MSG group was significantly greater than those in the CON and/or MSG groups. In spite of the increase in the relative adrenal weight, there was a significant decrease in the plasma corticosterone levels in the CVS+MSG group as compared to all other groups, except the naïve group. These results suggest that impaired HPA axis function as well as the decrease in the behavioral activity in adult rats can be induced by chronic MSG administration under CVS rather than CVS alone.

Dual-time-point positron emission tomography findings of benign mediastinal fluorine-18-fluorodeoxyglucose uptake in tuberculosis-endemic region

Background: We performed dual-time-point positron emission tomography imaging in patients without evidences of mediastinal lymph node metastasis to investigate the characteristics of benign mediastinal fluorine-18-fluorodeoxyglucose (FDG) uptake. Materials and Methods: One-hundred and eighteen mediastinal lesions of 24 patients were included for this study. On the early and delayed positron emission tomography images, size, attenuation, maximum standardized uptake value (SUV) and retention indices (RI) were recorded for lymph node characterization. Results: The mean SUV on the early and delayed scan of 118 lymph nodes was 3.3±1.2 and 4.2±1.7, respectively. The mean RI was 26.4±24.5%. Higher FDG uptake was observed in patients with calcified nodules and bilateral FDG uptake and in lymph nodes with calcification or short-axis diameter larger than 10 mm. Conclusion: In tuberculosis-endemic area, the increments of SUV or RI were frequently observed in benign mediastinal lymph nodes, and these values might not be the accurate indicators of malignant disease for mediastinal FDG uptake.

Interpretation of scanning probe microscope image of the structure of atomic vacancy on graphite: ab initio periodic Hartree–Fock calculations ☆

Abstract By using the CRYSTAL 95 program, ab initio periodic Hartree–Fock (PHF) calculations with the full potential and 6-21G∗ basis set are applied to the interpretation of scanning tunneling microscope (STM) and atomic force microscopy (AFM) image of the structure of atomic vacancy in graphite. Our results show that change in the total electron density when compared with the ideal structure is considerable at the missing atom site, but it is not considerable beyond a distance upon the missing atom site. However, the partial charge density, which originates from the states near the Fermi energy is enhanced at the atoms surrounding the vacancy. These results are in a good agreement with those of Hahn et al. (Phys. Rev. B 53 (1996) R1725), who take that vacancies are transparent in AFM but imaged as surface protrusions in STM. In conclusion, our results should clarify the reason why vacant sites of graphite are visible shown in STM, while they are not easy to detect in AFM.

Radiolabeled Chitosan Hydrogel Containing VEGF Enhances Angiogenesis in a Rodent Model of Acute Myocardial Infarction

Vascular endothelial growth factor (VEGF) plays a pivotal role in angiogenesis in an infarcted myocardium. The purpose of the current investigation was to validate whether a radiolabeled VEGF delivery system can be effectively monitored in vivo, and to ascertain whether the growth factor induces an angiogenic effect to facilitate recovery from infarct conditions in rodent myocardial infarction (MI) models. Rat MI models were divided into three groups, one with left anterior descending coronary artery (LAD) ligation with no injection (the control group), one with LAD ligation and I-131 VEGF injection (the VEGF group), and one with LAD ligation and I-131 VEGF-loaded chitosan injection (the VIC group). On day 7 after injection, autoradiography imaging was performed, followed by semiquantitative and histopathologic analyses. In semi-quantitative analysis, the mean anterior-to-inferior wall ratio of the VIC group was significantly higher than those of the control and VEGF groups (p<0.05). Histopathologic experiments revealed a marked increase in microvascular density in the VIC group compared to those of the control and VEGF groups (p<0.05). Intramyocardially injected VIC was not only effectively monitored in vivo, but also stimulated therapeutic angiogenesis in the infarcted myocardium. Our findings support that the developed VIC is a novel theranostic tool to improve myocardial perfusion following myocardial infarction.

Assessment of cerebral hemodynamics to acetazolamide using brain perfusion SPECT in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary microangiopathy caused by mutations in the Notch3 gene located on chromosome 19, leading to 4 cardinal features with aura, cerebrovascular ischemic events, mood disturbances, and dementia. Acetazolamide (ACZ) has been promoted as a drug to determine cerebral hemodynamics, including cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) in patients with cerebrovascular disease. In CADASIL patients with small-vessel disease, ACZ may be possible to increase CBF. We present that reduced CBF was dramatically improved after administration of ACZ on Tc-99m ECD brain perfusion SPECT in a CADASIL patient.

Normal Physiologic and Benign Foci with F-18 FDG Avidity on PET/CT in Patients with Breast Cancer

PurposeThe aim of this study was to evaluate the physiologic and benign F-18 fluorodeoxyglucose (FDG) avid foci in patients with breast cancer.MethodsOn 309 F-18 FDG PET/CT scans of 241 women with breast cancer, the hypermetabolic lesions compared with the surrounding normal region were evaluated retrospectively. Available reports of other relevant radiological imaging, medical records, and follow-up PET/CT were reviewed for explanations of the abnormal uptake.ResultsAmong the 70 physiologic foci, muscular uptake of the lower neck following the surgical and/or radiation therapy of ipsilateral breast (29%), hypermetabolic ovaries (16%) and uterine (10%) uptake during the ovulatory and menstrual phases during the normal menstrual cycle were identified, and also hypermetabolic brown fat in cold-induced thermogenesis (7%), non-specific bowel uptake (35%) were observed. Among the 147 benign lesions, sequelae of the chest wall and breasts following surgical and/or radiation therapy, were often observed (27%). Hypermetabolic thyroid glands were noted as adenomas and chronic thyroiditis (18%). Reactive hyperplasia of cervical or mediastinal lymph nodes (32%), degenerative osteoarthritis and healed fractures (15%), hypermetabolic benign lung lesions (6%) were observed.ConclusionAltered physiologic and benign F-18 FDG uptake in the lower cervical muscle and chest wall following ipsilateral breast surgery or radiotherapy were common, and also normal physiologic uptake in ovary and uterus, brown fat, thyroid were considered as predominant findings in women patients with breast cancer. Knowledge of these findings might aid in the interpretation of FDG PET/CT in patients with breast cancer.