Joon-Kee Yoon

A comparison of cerebral glucose metabolism in Parkinson's disease, Parkinson's disease dementia and dementia with Lewy bodies

Parkinsons disease dementia (PDD) and dementia with Lewy bodies (DLB) share many similar aspects, and making a clinical diagnosis of one disorder over the other relies heavily on an arbitrary criterion, so‐called 1‐year rule. This study was designed to search for any difference of metabolic patterns in these two disorders using F‐18 fluorodeoxyglucose (FDG) positron emission tomography (PET) images.

Molecular Photoacoustic Imaging of Follicular Thyroid Carcinoma

Purpose: To evaluate the potential of targeted photoacoustic imaging as a noninvasive method for detection of follicular thyroid carcinoma. Experimental Design: We determined the presence and activity of two members of matrix metalloproteinase family (MMP), MMP-2 and MMP-9, suggested as biomarkers for malignant thyroid lesions, in FTC133 thyroid tumors subcutaneously implanted in nude mice. The imaging agent used to visualize tumors was MMP-activatable photoacoustic probe, Alexa750-CXeeeeXPLGLAGrrrrrXK-BHQ3. Cleavage of the MMP-activatable agent was imaged after intratumoral and intravenous injections in living mice optically, observing the increase in Alexa750 fluorescence, and photoacoustically, using a dual-wavelength imaging method. Results: Active forms of both MMP-2 and MMP-9 enzymes were found in FTC133 tumor homogenates, with MMP-9 detected in greater amounts. The molecular imaging agent was determined to be activated by both enzymes in vitro, with MMP-9 being more efficient in this regard. Both optical and photoacoustic imaging showed significantly higher signal in tumors of mice injected with the active agent than in tumors injected with the control, nonactivatable, agent. Conclusions: With the combination of high spatial resolution and signal specificity, targeted photoacoustic imaging holds great promise as a noninvasive method for early diagnosis of follicular thyroid carcinomas. Clin Cancer Res; 19(6); 1494–502. ©2013 AACR.

In vivo tracking of 111In-labeled bone marrow mesenchymal stem cells in acute brain trauma model

INTRODUCTION This study was to evaluate the in vivo distribution of intravenously transplanted bone marrow-derived mesenchymal stem cells (BMSCs) in an acute brain trauma model by (111)In-tropolone labeling. METHODS Rat BMSCs were labeled with 37 MBq (111)In-tropolone. Their labeling efficiency and in vitro retention rate were measured. The viability and proliferation of labeled BMSCs were evaluated for 14 days after labeling. The biodistribution of (111)In-labeled BMSCs in trauma models was compared with those of sham-operated rats and normal rats on gamma camera images. The migration of (111)In-BMSCs to the traumatic brain was evaluated using confocal microscope. RESULTS The labeling efficiency of (111)In-BMSCs was 66+/-5%, and their retention rate was 85.3% at 1 h after labeling. There was no difference in the number of viable cells between (111)In-BMSCs and controls at 48 h after labeling. However, the proliferation of (111)In-BMSCs was inhibited after the third day of labeling, and it did not reach confluency. On gamma camera images, most of the (111)In-BMSCs uptake was observed in the liver and spleen at the second day of injection. The brain uptake of (111)In-BMSCs was detected prominently in trauma models (1.4%) than in sham-operated (0.5%) or normal rats (0.3%). Radiolabeled BMSCs were observed at the traumatic brain on the confocal microscope as they have a homing capacity, although its proliferation capacity was suppressed. CONCLUSION Although growth inhibition by (111)In-labeling need to be evaluated further prior to use in humans, (111)In-labeled BMSCs are useful for the tracking of intravenously transplanted mesenchymal stem cells in brain disease models.

Clinical usefulness of the fluorodeoxyglucose (FDG)-PET maximal standardized uptake value (SUV) in combination with CT features for the differentiation of adenocarcinoma with a bronchioloalveolar carcinoma from other subtypes of non-small cell lung cancers

PURPOSE To evaluate the clinical usefulness of fluorodeoxyglucose (FDG)-PET maximal SUV in combination with CT features for differentiation of adenocarcinoma with bronchioloalveolar carcinoma (BAC) from other subtypes of non-small cell lung cancer (NSCLC). MATERIALS AND METHODS This retrospective study included 125 patients (104 men and 21 women; mean age, 64 years) who underwent CT and subsequent FDG-PET examinations for preoperative evaluation and underwent curative intent operation with the final diagnoses of NSCLC made by surgical histopathology. We categorized NSCLC into adenocarcinoma with BAC feature and other subtypes. Finally, there were 16 cases of adenocarcinoma with BAC and 109 cases of other NSCLC subtypes included in the study. Several CT features of lung cancer were analyzed, including tumor size, presence of spiculation, margin (irregular or smooth), pattern of the mass (pure solid, pure ground glass opacity and mixed), associated pleural effusion and location (center, mid and periphery). Maximal SUV and visual scores of FDG uptakes of primary NSCLC were evaluated. The diagnostic performances of CT alone, PET alone, and combination of two modalities to predict adenocarcinoma with BAC from other subtypes of NSCLC were calculated. RESULTS A nodule with a mixed pattern with partly solid and ground glass opacity was significantly more frequent CT feature of an adenocarcinoma with BAC (8/16, 50%) as compared with the other subtypes (2/109, 1.8%) (p<0.0001). Maximal SUV of adenocarcinoma with BAC (mean=7.2) was significantly lower than that of other subtypes of NSCLC (mean=13.33) (p<0.0001). Sensitivity, specificity, PPV, and NPV of CT for differentiating adenocarcinoma with BAC from other subtypes was 50% (8/16), 98.2% (107/109), 80% (8/10), and 93% (107/115), respectively. Sensitivity, specificity, PPV, and NPV of FDG-PET was 68.8% (11/16), 86.2% (94/109), 42.3% (11/26), and 94.9% (94/99), respectively. Sensitivity, specificity, PPV, and NPV of combination of two modalities was 81.3% (13/16), 85.3% (93/109), 44.8% (13/29), 96.9% (93/96), respectively. CONCLUSION Careful combined assessment of the FDG-PET maximal SUV and CT findings have the potential to differentiate an adenocarcinoma with BAC from other NSCLC subtypes, such as a pure BAC. These findings might be useful for imaging interpretations and will help initial planning of NSCLC management.

Prognostic significance of the intratumoral heterogeneity of (18) F-FDG uptake in oral cavity cancer.

We evaluated the prognostic value of the intratumoral heterogeneity of 18F‐FDG uptake in oral cavity cancer.

Abnormal bone scan in an adult with osteopoikilosis

AbstractOsteopoikilosis is rare, autosomal dominant bone disorder diagnosed by radiologic features. The findings include multiple small, circumscribed round areas of increased bone density distributed symmetrically in a periarticular location. The lesions cluster at the ends of long bones, around th

Unexpected dissemination patterns in lymphoma progression revealed by serial imaging within a murine lymph node.

Non-Hodgkin lymphoma (NHL) is a heterogeneous and highly disseminated disease, but the mechanisms of its growth and dissemination are not well understood. Using a mouse model of this disease, we used multimodal imaging, including intravital microscopy (IVM) combined with bioluminescence, as a powerful tool to better elucidate NHL progression. We injected enhanced green fluorescent protein and luciferase-expressing Eμ-Myc/Arf(-/-) (Cdkn2a(-/-)) mouse lymphoma cells (EL-Arf(-/-)) into C57BL/6NCrl mice intravenously. Long-term observation inside a peripheral lymph node was enabled by a novel lymph node internal window chamber technique that allows chronic, sequential lymph node imaging under in vivo physiologic conditions. Interestingly, during early stages of tumor progression we found that few if any lymphoma cells homed initially to the inguinal lymph node (ILN), despite clear evidence of lymphoma cells in the bone marrow and spleen. Unexpectedly, we detected a reproducible efflux of lymphoma cells from spleen and bone marrow, concomitant with a massive and synchronous influx of lymphoma cells into the ILN, several days after injection. We confirmed a coordinated efflux/influx of tumor cells by injecting EL-Arf(-/-) lymphoma cells directly into the spleen and observing a burst of lymphoma cells, validating that the burst originated in organs remote from the lymph nodes. Our findings argue that in NHL an efflux of tumor cells from one disease site to another, distant site in which they become established occurs in discrete bursts.

Resting cerebral glucose metabolism and perfusion patterns in women with posttraumatic stress disorder related to sexual assault.

In the literature, numerous trials using neuroimaging techniques have investigated brain function in patients with post-traumatic stress disorder (PTSD). However, the contrasting results showed that improvements, including in the study design, were required to reach consistent and convincing conclusions. This study evaluated the functional neuroimaging pattern of resting cerebral blood flow and glucose metabolism in patients with PTSD related to sexual assault. Twelve patients were enrolled for both brain single photon emission computed tomography (SPECT) and (18)F-fluorodeoxyglucose positron emission tomography (PET) investigations. All data were analyzed with statistical parametric mapping 2 (SPM2). The PTSD patients showed significant relative decreases in perfusion in the left hippocampus and in the basal ganglia compared with the control group. The PTSD group also had significantly lower cerebral glucosemetabolic activity in the left hippocampus and the superior temporal and precentral gyri than in the control group. These specific patterns of perfusion and glucose metabolism may be closely related to various neurophysiologic symptoms of PTSD.

Associated conditions and clinical significance of awake bruxism.

Background:  Awake bruxism is defined as an oral parafunctional activity that includes clenching and grinding of teeth during wakefulness. Confirming the possible related anatomy and the clinical significance of awake bruxism in geriatric hospitals is the aim of this study.

Effectiveness of [124I]-PET/CT and [18F]-FDG-PET/CT for Localizing Recurrence in Patients with Differentiated Thyroid Carcinoma

Although the prognosis of patients with differentiated thyroid carcinoma (DTC) is generally encouraging, a diagnostic dilemma is posed when an increasing level of serum thyroglobulin (Tg) is noted, without detection of a recurrent tumor using conventional imaging tools such as the iodine-131 whole-body scanning (the [131I] scan) or neck ultrasonography (US). The objective of the present study was to evaluate the diagnostic value of [124I]-PET/CT and [18F]-FDG-PET/CT in terms of accurate detection of both iodine- and non-iodine-avid recurrence, compared with that of conventional imaging such as the [131I] scan or neck ultrasonography (US). Between July 2009 and June 2010, we prospectively studied 19 DTC patients with elevated thyroglobulin levels but who do not show pathological lesions when conventional imaging modalities are used. All involved patients had undergone total thyroidectomy and radioiodine (RI) treatment, and who had been followed-up for a mean of 13 months (range, 6-21 months) after the last RI session. Combined [18F]-FDG-PET/CT and [124I]-PET/CT data were evaluated for detecting recurrent DTC lesions in study patients and compared with those of other radiological and/or cytological investigations. Nine of 19 patients (47.4%) showed pathological [18F]-FDG (5/19, 26.3%) or [124I]-PET (4/19, 21.1%) uptake, and were classed as true-positives. Among such patients, disease management was modified in six (66.7%) and disease was restaged in seven (77.8%). In particular, the use of the described imaging combination optimized planning of surgical resection to deal with locoregional recurrence in 21.1% (4/19) of patients, who were shown to be disease-free during follow-up after surgery. Our results indicate that combination of [18F]-FDG-PET/CT and [124I]-PET/CT affords a valuable diagnostic method that can be used to make therapeutic decisions in patients with DTC who are tumor-free on conventional imaging studies but who have high Tg levels.