Bom Sahn Kim

Intratumoral metabolic heterogeneity predicts invasive components in breast ductal carcinoma in situ

AbstractObjectivesThis study investigated whether texture-based imaging parameters could identify invasive components of ductal carcinoma in situ (DCIS).MethodsWe enrolled 65 biopsy-confirmed DCIS patients (62 unilateral, 3 bilateral) who underwent 18 F-FDG PET, diffusion-weighted imaging (DWI), or breast-specific gamma imaging (BSGI). We measured SUVmax and intratumoral metabolic heterogeneity by the area under the curve (AUC) of cumulative SUV histograms (CSH) on PET, tumour-to-normal ratio (TNR) and coefficient of variation (COV) as an index of heterogeneity on BSGI, minimum ADC (ADCmin) and ADC difference (ADCdiff) as an index of heterogeneity on DWI. After surgery, final pathology was categorized as pure-DCIS (DCIS-P), DCIS with microinvasion (DCIS-MI), or invasive ductal carcinoma (IDC). Clinicopathologic features of DCIS were correlated with final classification.ResultsFinal pathology confirmed 44 DCIS-P, 14 DCIS-MI, and 10 IDC. The invasive component of DCIS was significantly correlated with higher SUVmax (p = 0.017) and lower AUC-CSH (p < 0.001) on PET, higher TNR (p = 0.008) and COV (p = 0.035) on BSGI, lower ADCmin (p = 0.016) and higher ADCdiff (p = 0.009) on DWI, and larger pathologic size (p = 0.018). On multiple regression analysis, AUC-CSH was the only significant predictor of invasive components (p = 0.044).ConclusionsThe intratumoral metabolic heterogeneity of 18 F-FDG PET was the most important predictor of invasive components of DCIS.Key Points• Preoperative identification of invasion in DCIS is important for axillary nodal management • Higher SUVmaxand lower AUC-CSH from FDG PET may indicate invasive components of DCIS • Higher TNR and COV from BSGI may indicate invasive components of DCIS • Lower ADCminand higher ADCdifffrom DWI may indicate invasive components of DCIS • AUC-CSH, an index of metabolic heterogeneity, is an independent predictor for invasive components

Aromatic radiofluorination and biological evaluation of 2-aryl-6-[18F] fluorobenzothiazoles as a potential positron emission tomography imaging probe for β-amyloid plaques

To develop agents for radionuclide imaging Aβ plaques in vivo, we prepared three fluorine-substituted analogs of arylbenzothiazole class; compound 2 has a high affinity for Aβ (K(i)=5.5nM) and the specific binding to Aβ in fluorescent staining. In preparation for the synthesis of these arylbenzothiazole analogs in radiolabeled form as an Aβ plaques-specific positron emission tomography (PET) imaging probe, we investigated synthetic route suitable for its labeling with the short-lived PET radionuclide fluorine-18 (t(1/2)=110min) and diaryliodonium tosylate precursors (12, 13a-e and 14). 2-Aryl-6-[(18)F]fluorobenzothiazoles ([(18)F]1-3) were synthesized in efficiently short reaction times (40-60min) with high radiochemical yields (19-40%), purities (>95%) and specific activities (85-118GBq/μmol). Tissue distribution studies showed that high radioactivity of [(18)F]2 accumulated in the brain with rapid clearance in healthy mice. Radioactive metabolites were analyzed in brain samples of mice and corresponded to 81% of parent remained by 30min after a tail-vein injection. These results suggest that [(18)F]2 is a promising probe for evaluation of Aβ plaques imaging in brain using PET.

[18F]Fluoromethyl-PBR28 as a Potential Radiotracer for TSPO: Preclinical Comparison with [11C]PBR28 in a Rat Model of Neuroinflammation

To develop radiotracer for the translocator protein 18 kDa (TSPO) in vivo, N-(2-[(18)F]fluoromethoxybenzyl)-N-(4-phenoxypyridin-3-yl)acetamide ([(18)F]1, [(18)F]fluoromethyl-PBR28) was prepared by incorporating of fluorine-18 into triazolium triflate-PBR28 precursor (7). The radiochemical yield of [(18)F]1 after HPLC purification was 35.8 ± 3.2% (n = 11, decay corrected). Radiotracer [(18)F]1 was found to be chemically stable when incubated in human serum for 4 h at 37 °C. Both aryloxyanilide analogs (1 and 2) behaved similarly in terms of lipophilicity and in vitro affinity for TSPO. Here, both radiotracers were directly compared in the same inflammatory rat to determine whether either radiotracer provides more promising in vivo TSPO binding. Uptake of [(18)F]1 in the inflammatory lesion was comparable to that of [(11)C]PBR28, and [(18)F]1 rapidly approached the highest target-to-background ratio at early imaging time (35 min postinjection versus 85 min postinjection for [(11)C]PBR28). These results suggest that [(18)F]1 is a promising radiotracer for imaging acute neuroinflammation in rat. In addition, our use of a triazolium triflate precursor for [(18)F]fluoromethyl ether group provides the convenient application for radiofluorination of radiotracer containing a methoxy group.

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.

Background 99mTc-methoxyisobutylisonitrile uptake of breast-specific gamma imaging in relation to background parenchymal enhancement in magnetic resonance imaging.

AbstractObjectivesThis study investigated factors that could affect background uptake of 99mTc- methoxyisobutylisonitrile (MIBI) on normal breast by breast-specific gamma imaging (BSGI). In addition, the impact of background 99mTc-MIBI uptake on the diagnostic performance of BSGI was further investigated.MethodsOne hundred forty-five women with unilateral breast cancer who underwent BSGI, MRI, and mammography were retrospectively enrolled. Background uptake on BSGI was evaluated qualitatively and quantitatively. Patients were classified into non-dense and dense breast groups according to mammographic breast density. Background parenchymal enhancement (BPE) was rated according to BI-RADS classification. The relationship of age, menopausal status, mammographic breast density, and BPE with background 99mTc-MIBI uptake was analyzed.ResultsHeterogeneous texture and high background uptake ratio on BSGI were significantly correlated with younger age (p < 0.001, respectively), premenopausal status (p < 0.001 and p = 0.003), dense breast (p < 0.001, respectively), and marked BPE (p < 0.001, respectively). On multivariate analysis, only BPE remained a significant factor for background MIBI uptake (p < 0.001).There was a significant reduction in positive predictive value (p = 0.024 and p = 0.002) as background MIBI uptake and BPE grade increased.ConclusionsBPE on MRI was the most important factor for background MIBI uptake on BSGI. High background MIBI uptake or marked BPE can diminish the diagnostic performance of BSGI.Key Points• Age, menopause, density, and background parenchymal enhancement affect background MIBI uptake. • BPE is an independent factor for background MIBI uptake on BSGI. • Marked BPE may impair BSGI interpretation.

Proximity of Posterior Teeth to the Maxillary Sinus and Buccal Bone Thickness: A Biometric Assessment Using Cone-beam Computed Tomography

INTRODUCTION The aims of this study were to evaluate the vertical and horizontal relationships between the maxillary sinus floor (MSF) and the root apices of maxillary posterior teeth with various root configurations and the distance from the root apex to the MSF and the buccal cortical plate. METHODS Serial axial, coronal, sagittal, and paraxial cone-beam computed tomographic images of 132 Korean patients with fully erupted bilateral maxillary posterior teeth were analyzed. The vertical and horizontal relationships between the roots of maxillary posterior teeth and the MSF were determined. Distances from the apex to the MSF and the buccal bone plate were measured. The data were correlated with age, sex, side, and tooth type. RESULTS In total, 2159 apices in 1056 teeth were evaluated. For the vertical relationships, the frequency in group 1, in which a root apex protruded into the MSF, significantly increased toward the posterior (first premolars: 1.5%, second premolars: 14.8%, first molars: 40.5%, second molars: 44.7%, P < .001). The apices of the mesiobuccal roots of the second molars were found frequently in group 1 (35.8%) and had the shortest mean vertical distance to the MSF (0.18 mm) and the thickest mean horizontal distance to the buccal cortical plate (4.99 mm) among buccal roots of 3-rooted molars (P < .001). The frequency of group 1 differed significantly by age (P < .05). No statistically significant difference was found in sex or side analysis. For the horizontal relationship between the molar roots and the MSF, most teeth were in group BP, in which the lowest point of the MSF was located centrally, relative to the roots (94.3% for first molars, 81.0% for second molars). For the first molars, no significant difference according to sex or side was found. However, the right side (P = .003) and males (P = .005) showed higher incidences for second molars. CONCLUSIONS The data in this study highlight the close proximity between the root apex of maxillary posterior teeth and the MSF and provide estimated distances from the root apex to the buccal cortical plate. Special care must be taken in treatment planning in the maxillary posterior region.

Cortico-Cortical Modulation Induced by 1-Hz Repetitive Transcranial Magnetic Stimulation of the Temporal Cortex

Background and Purpose Repetitive transcranial magnetic stimulation (rTMS) has potential as a noninvasive neuromodulation treatment method for various neuropsychiatric disorders, and repeated sessions of rTMS are more likely to enhance the therapeutic efficacy. This study investigated neurophysiologic and spatiodynamic changes induced by repeated 1-Hz rTMS of the temporal cortex using transcranial magnetic stimulation (TMS) indices and fluorodeoxyglucose positron emission tomography (FDG-PET). Methods Twenty-seven healthy subjects underwent daily 1-Hz active or sham rTMS of the right temporal cortex for 5 consecutive days. TMS indices of motor cortical excitability were measured in both hemispheres daily before and after each rTMS session, and 2 weeks after the last stimulation. FDG-PET was performed at baseline and after the 5 days of rTMS sessions. Results All subjects tolerated all of the sessions well, with only three of them (11.1%) reporting mild transient side effects (i.e., headache, tinnitus, or local irritation). One-Hz rTMS decreased motor evoked potential amplitudes and delayed cortical silent periods in the stimulated hemisphere. Statistical parametric mapping of FDG-PET data revealed a focal reduction of glucose metabolism in the stimulated temporal area and an increase in the bilateral precentral, ipsilateral superior and middle frontal, prefrontal and cingulate gyri. Conclusions Repeated rTMS sessions for 5 consecutive days were tolerated in all subjects, with only occasional minor side effects. Focal 1-Hz rTMS of the temporal cortex induces cortico-cortical modulation with widespread functional changes in brain neural networks via long-range neural connections.

The Clinical Meaning of Benign Colon Uptake in 18 F-FDG PET: Comparison with Colonoscopic Findings

Background/Aims Benign colon 18F-fluorodeoxyglucose (FDG) uptake is frequently observed in asymptomatic individuals. Aims of this study were to investigate the benign colon uptake by whole body FDG-positron emission tomography (PET) in asymptomatic adults and to correlate those results with colonoscopic and histologic findings. Methods Among 3,540 subjects who had undergone FDG-PET, 43 subjects who were diagnosed to have benign colon uptake in FDG-PET and underwent colonoscopy were retrospectively reviewed. Subjects were classified as diffuse or focal groups based on their FDG uptake patterns. PET results were analyzed together with colonoscopic and histologic findings. Results Forty-three subjects showed benign colon uptake in FDG-PET; 28 of them were shown as the diffuse group, while other 15 subjects were classified as the focal group. Five subjects among those showed diffuse uptake were diagnosed as adenoma. Seven among 15 subjects who showed focal uptake were diagnosed as adenocarcinoma (n=2), adenoma (n=3), or non-neoplastic polyp (n=2). Positive predictive values were 25% in the diffuse group and 47% in the focal group. Conclusions We recommend that patients showing benign FDG uptake in the colon should be further evaluated by colonoscopy, especially for patients with focal FDG uptake.

Effectiveness of Breast-Specific Gamma Imaging (BSGI) for Breast Cancer in Korea: A Comparative Study

Abstract:  Despite the fact that mammography has been the golden standard in breast cancer detection for several decades, its sensitivity decreases for women with dense breast tissue, which happens to be common in Korea. As an alternative, breast ultrasonography can be effective diagnostic modalities that complement the defect of mammography. Recently, breast‐specific gamma imaging (BSGI) has been introduced as a new diagnostic modality for breast cancer. This study was designed to analyze the effectiveness of BSGI in particular. In a retrospective study, 471 patients underwent BSGI, breast ultrasonography, and mammography simultaneously during the period between February 2009 and March 2010. The indications of BSGI were as follows: (a) patient who was diagnosed with malignancy prior to surgery, (b) patient who is under follow up after cancer surgery, (c) patient with lesions which cannot be evaluated by breast ultrasonography or mammography, (d) patient with multiple benign lesions, and (e) patient with suspicious lesion who refuses biopsy. Among these patients, 121 patients underwent biopsy, whereas others were followed up with imaging studies. We compared the BSGI results with those of mammography, breast ultrasonography, and pathology. The mean age of the patients was 49.63 ± 10.43 years. There were 107 patients with 110 malignant lesions and 364 patients with benign lesions. Total 474 lesions were evaluated. The sensitivities of BSGI, mammography, and breast ultrasonography were 94.45%, 93.64%, and 98.18%, respectively, whereas the specificities of BSGI, mammography, and breast ultrasonography were 90.93%, 90.66%, and 87.09%, respectively. The sensitivity and specificity of BSGI for axillary lymph node (LN) status were 44.7 4% and 87.88%, respectively. BSGI is a good complementary imaging modality with high sensitivity and high specificity for breast cancer detection. However, it has low efficacy for the evaluation for axillary LN status.

Magnetic resonance imaging and positron emission tomography of a giant multiseptated pyomyoma simulating an ovarian cancer

A case of giant pyomyoma misdiagnosed as an ovarian cancer in a magnetic resonance imaging (MRI) and a positron emission tomography (PET) scan is presented. An unusual huge, multiseptated, and pedunculated character, as well as a normal-sized uterus on imaging studies, caused the misinterpretation of the MRI and PET scan images as an ovarian mucinous cystadenocarcinoma.