Usefulness of Preoperative 18F-FDG PET/CT for Patients with Thymic Epithelial Tumors.

BACKGROUND: The purpose of this study was to investigate the relationship between preoperative FDG-PET parameters and the World Health Organization (WHO) classification or Masaoka staging system of thymic epithelial tumors. METHODS: We retrospectively reviewed 32 patients with histologically proven thymic epithelial tumors who underwent FDG-PET/CT before surgical resection. FDG-PET parameters, including the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolytic activity (TLG), were measured. These PET parameters were compared in the Masaoka staging system and WHO classification. A receiver operating characteristics (ROC) analysis was performed to identify the cut-off values of PET parameters for the accurate differentiation of early and advanced stages in the Masaoka staging system. RESULTS: There were 17 low-risk thymomas (1 type A, 9 type AB, and 7 type B1), 8 high-risk thymomas (4 type B2 and 4 type B3), and 7 thymic carcinomas (7 squamous cell carcinoma). Their Masaoka stages were as follows: 24 in the early stage (stages I and II) and 8 in the advanced stage (stage III). Regarding the WHO classification, only SUVmax showed a significant difference (P < 0.05). In the Masaoka stage, all PET parameters were significantly higher in the advanced stage than in the early stage (P < 0.05). In the ROC analysis to predict the early and advanced stages in thymic epithelial tumors, the area under the curve was the highest for TLG among the PET parameters examined and the cut-off value of TLG for discriminating the early from advanced stage with maximal sensitivity and specificity was 30.735. CONCLUSION: Although volumetric PET parameters, such as MTV and TLG, did not correlate with the WHO classification, a significant correlation was observed between SUVmax and the WHO classification. In the Masaoka staging system, volumetric PET parameters may achieve more precise staging than SUVmax.

Role of Neuroimaging on Differentiation of Parkinson's Disease and Its Related Diseases.

An accurate diagnosis of Parkinson's disease (PD) is a prerequisite for therapeutic management. In spite of recent advances in the diagnosis of parkinsonian disorders, PD is misdiagnosed in between 6 and 25% of patients, even in specialized movement disorder centers. Although the gold standard for the diagnosis of PD is a neuropathological assessment, neuroimaging has been playing an important role in the differential diagnosis of PD and is used for clinical diagnostic criteria. In clinical practice, differential diagnoses of PD include atypical parkinsonian syndromes such as dementia with Lewy bodies, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, caused by a striatal dopamine deficiency following nigrostrial degeneration. PD may also be mimicked by syndromes not associated with a striatal dopamine deficiency such as essential tremor, drug-induced parkinsonism, and vascular parkinsonism. Moreover, difficulties are associated with the clinical differentiation of patients with parkinsonism from those with Alzheimer's disease. In this review, we summarize the typical imaging findings of PD and its related diseases described above using morphological imaging modalities (conventional MR imaging and neuromelanin MR imaging) and functional imaging modalities (99mTc-ethyl cysteinate dimer perfusion single photon emission computed tomography, 123I-metaiodobenzylguanidine myocardial scintigraphy, and 123I-FP-CIT dopamine transporter single photon emission computed tomography) that are clinically available in most hospitals. We also attempt to provide a diagnostic approach for the differential diagnosis of PD and its related diseases in clinical practice.

Evaluation of Parkinson's disease by neuromelanin-sensitive magnetic resonance imaging and 123I-FP-CIT SPECT.

Background Both neuromelanin-sensitive magnetic resonance imaging (NmMRI) and 123I-FP-CIT single photon emission computed tomography (SPECT) (DaTSCAN) assist the diagnosis of Parkinson's disease (PD). However, there have been few studies investigating a correlation between them. Purpose To correlate the utility of NmMRI and DaTSCAN and to evaluate the relationship between both imaging findings and the Unified PD rating scale part III (UPDRS III) score for the diagnosis and management of PD. Material and Methods Seventeen patients with PD who underwent both NmMRI and DaTSCAN were included. We measured the volume of the neuromelanin-positive substantia nigra pars compacta (SNc volume) on NmMRI and measured the specific binding ratio (SBR) on DaTSCAN. The asymmetry index (AI) of the SNc volume and SBR were also calculated. We evaluated the relationship between the UPDRS III score and the SNc volume and SBR, respectively. Results The SNc volume showed a significant correlation with the SBR. The AIs of them also showed a significant correlation. Both the mean of the bilateral SBR and the mean of the bilateral SNc volume showed significant negative correlations with the UPDRS III score. However, the correlation between the SBR and the UPDRS III score was stronger than that between the SNc volume and the UPDRS III score. Conclusion Both NmMRI and DaTSCAN are helpful for PD diagnosis. However, we conclude that DaTSCAN is more suitable for the evaluation of the clinical motor severity and would be more useful for the management of PD patients than NmMRI.

The spectrum of imaging appearances of müllerian duct anomalies: focus on MR imaging.

Müllerian duct anomalies (MDAs) are the result of incomplete development, vertical or lateral fusion, or absorption of the müllerian ducts. The range of anomalies includes uterovaginal agenesis or hypoplasia, unicornuate uterus, uterus didelphys, bicornuate uterus, septate uterus, and arcuate uterus. Correct diagnosis and classification of these anomalies are essential because pregnancy outcomes and treatment options vary between the types of anomaly. Furthermore, early identification of MDAs helps to avoid prolonged symptomatic periods and the complications that may subsequently arise, such as infertility, endometriosis, and neoplasm. Although many of these abnormalities are initially diagnosed by ultrasound or hysterosalpingography, MR imaging is the most accurate noninvasive modality available for classification of the various anomalies because of its better anatomic assessment compared with other diagnostic modalities. Familiarity with the wide variety of MDA presentations can help in the planning of appropriate treatment.

Pictorial review of 18F-FDG PET/CT findings in musculoskeletal lesions.

We herein reviewed 18F-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) findings in a number of musculoskeletal lesions including malignant tumors, benign tumors, and tumor-like lesions with correlations to other radiographic imaging modalities, and described the diversity of the 18F-FDG PET/CT findings of this entity. Malignant primary musculoskeletal tumors are typically 18F-FDG avid, whereas low-grade malignant tumors show mild uptake. Benign musculoskeletal tumors generally show a faint uptake of 18F-FDG, and tumor-like conditions also display various uptake patterns of 18F-FDG. Although musculoskeletal tumors show various uptakes of 18F-FDG on PET/CT, its addition to morphological imaging modalities such as CT and MRI is useful for the characterization and differentiation of musculoskeletal lesions.

Correlation between neuromelanin-sensitive MR imaging and (123)I-FP-CIT SPECT in patients with parkinsonism.

INTRODUCTION: Neuromelanin-sensitive MR imaging (MRI) can visualize neuromelanin-containing neurons in the substantia nigra pars compacta (SNc), and its utility has been reported in the evaluation of parkinsonism. Conversely, dopamine transporter imaging by (123)I-N-v-fluoropropyl-2b-carbomethoxy-3b-(4-iodophenyl)nortropane (FP-CIT) SPECT (DaTSCAN) is now an established method for evaluating parkinsonism, detecting presynaptic dopamine neuronal dysfunction. Both methods can assist differentiating neurodegenerative and other forms of parkinsonism. However, to our knowledge, there have been no studies concerning a correlation between the two methods. The aim of this study was to assess the utility of neuromelanin-sensitive MRI for diagnosing parkinsonism by examining a correlation with DaTSCAN. METHODS: Twenty-three patients with parkinsonism who underwent both neuromelanin-sensitive MRI and DaTSCAN were included. We measured the neuromelanin-positive SNc region volume by manually contouring the high signal intensity region of the SNc on neuromelanin-sensitive MRI and measured the specific binding ratio (SBR) on DaTSCAN. The asymmetry index of neuromelanin-positive SNc volume and the asymmetry index of SBR were also calculated. RESULTS: The volume of the neuromelanin-positive SNc region showed significant correlation with specific binding ratio (SBR) (right P < .001, ρ = 0.78, left P < .001, ρ = 0.86). The asymmetry index of neuromelanin-positive SNc volume also showed significant correlations with the asymmetry index of SBR (P < .001, ρ = 0.73). CONCLUSIONS: Decrease of the high signal intensity region of the SNc on neuromelanin-sensitive MRI would indicate damage to the nigrostriatal dopaminergic function as well as loss of dopaminergic neurons. We conclude that neuromelanin-sensitive MRI is a useful diagnostic biomarker for parkinsonism.

Significance of combined use of MRI and perfusion SPECT for evaluation of multiple system atrophy, cerebellar type.

BACKGROUND: Multiple system atrophy, cerebellar type (MSA-C) sometimes shows asymmetrical findings on magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT). PURPOSE: To assess the frequency and clinical significance of asymmetrical MRI and (99m)Tc-ethyl cysteinate dimer perfusion (ECD) SPECT findings of the cerebellum, middle cerebellar peduncle (MCP), and pons in MSA-C patients. MATERIAL AND METHODS: We retrospectively reviewed 28 patients with MSA-C who underwent MRI and (99m)Tc-ECD SPECT and evaluated laterality of atrophy and signal changes on MRI, and laterality of perfusion on (99m)Tc-ECD SPECT transversely and longitudinally. RESULTS: Laterality was identified for 64%, 61%, and 21% of atrophy in the cerebellum, MCP, and pons, respectively, on MRI and for 71% of atrophy in the cerebellum on perfusion SPECT. Concerning comparisons between the latest MRI and SPECT findings, laterality of cerebellar/MCP atrophy on MRI and decreased cerebellar perfusion on SPECT was matched in 57%, mismatched in 11%, and absent in 25% of patients. On past images, MRI and SPECT showed matched laterality in 33%, mismatched laterality in 27%, no laterality in 13%, and SPECT precedent laterality in 27% of patients. Including the latest and past images, asymmetrical changes were observed in 75% of patients. We could not identify any correlation between laterality of image findings and cerebellar symptoms in most patients. CONCLUSION: Asymmetrical changes on MRI and perfusion SPECT are common in MSA-C patients. Perfusion SPECT is useful for diagnosing MSA-C in the early stages from a functional perspective.

Apparent diffusion coefficient (ADC) measurement in ovarian tumor: Effect of region-of-interest methods on ADC values and diagnostic ability.

PURPOSE: To investigate the difference in apparent diffusion coefficient (ADC) measurements of differently shaped regions of interest (ROIs) in ovarian tumors, and to investigate the diagnostic ability of differently shaped ROIs in differentiating benign from malignant ovarian tumors. MATERIALS AND METHODS: Fifty-four patients with ovarian tumors with a solid component were evaluated. The patients underwent magnetic resonance (MR) examinations including diffusion-weighted imaging using a 3.0T MR system. Two readers measured ADCs using four ROI methods: freehand, square, round, and five small round ROIs. The interclass correlation coefficient (ICC) and repeated-measures analysis of variance were used to assess their measurement reliability and to compare ADCs for each ROI method. Receiver operating characteristic curve analysis and unpaired t-test on each ROI were used to differentiate benign and malignant ovarian tumors and assess the diagnostic ability. RESULTS: All ROI methods except the square ROI (0.56) showed good or excellent correlations (0.70-0.91). Minimum and mean ADC values differed significantly between the ROIs (P < 0.05). When using the freehand ROI, the minimum and mean ADC values were the lowest and highest, respectively. The optimal cutoff minimum and mean ADC values of each ROI for differentiating benign and malignant tumors were 0.81-1.06 × 10(-3) mm(2) /s and 1.15-1.52 × 10(-3) mm(2) /s, respectively. The areas under the curve showed no significant differences among the ADCs in the different ROI methods (P > 0.05). Minimum and mean ADCs from all ROIs showed significant differences between benign and malignant tumors (P < 0.05). CONCLUSION: The ROI shape influences ADC values and the optimal cutoff ADC values for differentiating benign from malignant ovarian tumors.

Comparative study of ¹8F-FDG-PET/CT imaging and serum hTERT mRNA quantification in cancer diagnosis.

We have reported on the clinical usefulness of human telomerase reverse transcriptase (hTERT) mRNA quantification in sera in patients with several cancers. Positron emission tomography-computed tomography (PET/CT) using ¹8F-fluorodeoxyglucose (FDG) has recently become an excellent modality for detecting cancer. We performed a diagnostic comparative study of FDG-PET/CT and hTERT mRNA quantification in patients with cancer. Four hundred seventy subjects, including 125 healthy individuals and 345 outpatients with cancer who had received medical treatments for cancer in their own or other hospitals, were enrolled. The subjects were diagnosed by FDG-PET/CT, and we measured their serum hTERT mRNA levels using real-time RT-PCR, correlating the quantified values with the clinical course. In this prospective study, we statistically assessed the sensitivity and specificity, and their clinical significance. hTERT mRNA and FDG-PET/CT were demonstrated to be correlated with the clinical parameters of metastasis and recurrence (P < 0.001), and of recurrence and tumor number in cancer compared with noncancer patients, respectively. A multivariate analysis showed a significant difference in the detection by FDG-PET/CT, ¹8F-FDG uptake, the detection by hTERT mRNA, and age. The use of both FDG-PET/CT and hTERT mRNA resulted in a positivity of 94.4% (221/234) for the detection of viable tumor cells. FDG-PET/CT is superior to hTERT mRNA quantification in the early detection of cancer and combinative use of FDG-PET/CT and hTERT mRNA may improve the diagnostic accuracy of cancer.

MR imaging findings of mass-forming endosalpingiosis in both ovaries: a case report.

A 50-year-old postmenopausal woman, who underwent ultrasonography at a periodic medical checkup, was found to have bilateral ovarian masses. Pelvic magnetic resonance imaging (MRI) showed bilateral multilocular cystic ovarian masses. The cyst walls and septal structure demonstrated contrast enhancement. She underwent bilateral salpingo-oophorectomy. Microscopic examination revealed that the cysts were lined with cuboidal or columnar epithelial cells, and some of the cells were ciliated. The final histopathological diagnosis was endosalpingiosis. Endosalpingiosis is defined as the presence of ectopic ciliated epithelium, resembling the normal endosalpinx, without endometrial stroma. It rarely presents as a tumor-like mass on MRI.

Intrathoracic splenosis: evaluation by superparamagnetic iron oxide-enhanced magnetic resonance imaging and radionuclide scintigraphy.

Splenosis represents the heterotopic autotransplantation of splenic tissue after either splenic trauma or surgery. Intrathoracic splenosis is a rare condition resulting from concomitant rupture of the spleen and the left hemidiaphragm. We report a case of splenosis in a 41-year-old male patient who had experienced severe thoracoabdominal injury including rupture of the spleen and left hemidiaphragm and post-traumatic splenectomy 20 years previously. Abnormal opacities in the cardiac region were noted on a chest radiograph at an annual checkup. Computed tomography (CT) of the chest demonstrated multiple, well-circumscribed pleura-based nodules at the posterior base of the left hemithorax and the left subdiaphragmatic area. On magnetic resonance imaging (MRI), the lesions were hypointense on T1-weighted images and hyperintense on T2-weighted images. After administration of superparamagnetic iron oxide (SPIO), the lesions showed decreased signal intensity but remained slightly hyperintense relative to liver parenchyma on T2-weighted images. (99m)Tc-labeled Sn colloid scintigraphy revealed multiple areas of increased activity consistent with the lesions on the CT and MRI scans. In addition to the history of splenic trauma and left hemothorax, SPIO-enhanced MRI and radionuclide scintigraphy, which can demonstrate phagocytic ability in the ectopic splenic tissue, were useful for confirming the diagnosis.

The effect of donepezil on increased regional cerebral blood flow in the posterior cingulate cortex of a patient with Parkinson's disease dementia.

It has been reported that the cholinesterase inhibitor, donepezil, improves cognitive decline in patients with Parkinson's disease dementia (PDD). However, this improvement was dominant for frontal lobe dysfunction, and the increase in the Mini-Mental State Examination (MMSE) score was minimal. We report a PDD patient with a decline of regional cerebral blood flow (rCBF) in the posterior cingulate cortex, precunei, and bilateral parietotemporal association cortex, as determined by single-photon emission computed tomography (SPECT) using the easy Z-scores imaging system (e-ZIS). Upon administration of donepezil, both the rCBF and MMSE score increased. The effectiveness of donepezil may vary based on the rCBF pattern in PDD.

Cloning and heterologous expression of the exo-beta-D-glucosaminidase-encoding gene (gls93) from a filamentous fungus, Trichoderma reesei PC-3-7.

We have previously reported on purification and characterization of an exo-beta-D-glucosaminidase (Gls93) from culture filtrate of Trichoderma reesei PC-3-7 grown on N-acetyl-D-glucosamine (GlcNAc). The corresponding gene of Gls93 was cloned and characterized in this work. To our knowledge, this is the first report on cloning of the gene encoding fungal exo-beta-D-glucosaminidase. This gene has no introns and encodes a polypeptide of 892 amino acids (aa) containing a secretion signal of 28 amino acids. Comparison of the amino acid sequence to known proteins and phylogenetic analysis indicated that gls93 belongs to the glycoside hydrolase family (GHF) 2 and should be further classified into a new subgroup, exo-beta-D-glucosaminidase subgroup. The gls93 transcription was biphasic when T. reesei was grown on GlcNAc, suggesting that the expression of this gene may be regulated by a complex mechanism, in which multiple regulatory proteins are involved. Furthermore, gls93 could be expressed in Pichia pastoris (ca. 0.49-mg/ml culture). The recombinant Gls93 had the two molecular forms, ca. 105 and 100 kDa, whose difference is caused by N-glycosylation. Both of them had the same properties such as specific activity and substrate specificity and showed only the activity of exo-beta-D-glucosaminidase but not those of beta-galactosidase, beta-glucuronidase, and beta-mannosidase belonging to GHF2.

[MR imaging for evaluation of severe facial nerve damage in patients with facial nerve palsy].

PURPOSE: To evaluate the usefulness of MR imaging for the detection of severe facial nerve damage in patients with facial nerve palsy. MATERIALS AND METHODS: We retrospectively reviewed 26 consecutive patients with facial nerve palsy (13 non-responders and 13 responders). T1-weighted, T2-weighted, and postcontrast T1-weighted images were obtained in all patients. FLAIR images were also obtained in 3 non-responders. RESULTS: The geniculate ganglion, labyrinthine segment, and tympanic segment or mastoid segment showed high signal intensity on T2-weighted images in 9 of 13 non-responders, whereas high signal intensity of the nerve was only seen in 1 of 13 responders. FLAIR imaging revealed high signal intensity lesions of the distal intrameatal segment in 2 non-responders. Contrast enhancement of the facial nerve showed a similar pattern in non-responders and responders. High signal intensity lesions on T2-weighted or FLAIR images showed enhancement on postcontrast T1-weighted images. CONCLUSION: These results suggest that a high signal intensity area on T2-weighted images is a marker of severe facial nerve damage. FLAIR imaging is useful for identification of T2-prolongation in the distal intrameatal segment.

Localization of chyle leakage site in postoperative chylothorax by oral administration of I-123 BMIPP.

The authors present a 71-year-old woman who had a right chylothorax after right upper lobectomy for lung cancer. As the chylothorax was considered to be due to thoracic duct injury at the time of operation, lymphoscintigraphy was performed by oral administration of I-123 beta-methyl-iodophenyl pentadecanoic acid (BMIPP). After visualization of the stomach and intestine, abnormal accumulation of the radiotracer was found initially around the right pulmonary hilum and then spread laterally in the upper pleural cavity, indicating chyle leakage in the region of the right pulmonary hilum. Scintigraphic finding was well correlated with the subsequent thoracoscopic observation, showing chyle leakage from a lymphatic tributary near its confluence to the thoracic duct at the level of the azygos continuation. The disruption site was ligated by video-assisted-thoracoscopic-surgery procedure with successful termination of the chyle leakage. Lymphoscintigraphy by oral administration of I-123 BMIPP is thought to be a useful method for localization of chyle leakage in patients with chylothorax induced by thoracic surgery.

[Cerebral atrophy and crossed cerebellar atrophy following acute subdural hematoma in infant].

Crossed cerebellar atrophy (CCA) on imaging study reflects secondary degeneration of the cerebellar hemisphere caused by neuronal disconnection with the contralateral cerebral hemisphere. We report an 11-month-old child with traumatic left acute subdural hematoma, who showed crossed cerebellar atrophy on MR images. Eighteen months after the trauma, MR images showed brain atrophy not only in the left cerebral hemisphere but also in the right cerebellar hemisphere. The cerebellar atrophy was prominent in the lateral part. This finding is consistent with CCA and may support neuronal interactions between the cerebral hemisphere and the lateral part of the contralateral cerebellar hemisphere.

Clinical usefulness of In-111 chloride and Tc-99m Sn colloid scintigraphy in the diagnosis of intrathoracic extramedullary hematopoiesis.

We report a case of intrathoracic extramedullary hematopoiesis associated with hemolytic anemia. While the paravertebral localization of the lesions demonstrated on CT and MRI was suspicious of intrathoracic extramedullary hematopoiesis, In-111 chloride and Tc-99m Sn colloid bone marrow scintigraphies showing a bone marrow element of the lesion were useful to confirm the diagnosis.

Sequential MR imaging and SPECT studies in herpes simplex encephalitis with crossed cerebellar hyperperfusion.

We report a case of herpes simplex encephalitis in which sequential MR imaging and SPECT studies showed interesting findings. SPECT in the acute stage showed wide increased uptake in the left cerebral hemisphere, as well as increased uptake in the contralateral right cerebellar hemisphere. T1-weighted images in the subacute stage showed hyperintense signals along the cerebral cortices, but T2*-weighted gradient-echo images did not show any signal decrease caused by the magnetic susceptibility effect of hemoglobin degradation. Sequential SPECT studies in addition to MR imaging facilitate precise understanding of the pathophysiology of herpes simplex encephalitis.

123I-Metaiodobenzylguanidine myocardial scintigraphy in panic disorder.

UNLABELLED: Although autonomic function has been investigated in panic disorder, previous studies have not yet revealed a consistent autonomic change in this disease. The purpose of this study was to evaluate the cardiac sympathetic function in panic disorder using (123)I-metaiodobenzylguanidine ((123)I-MIBG). METHODS: Myocardial imaging using (123)I-MIBG was performed on 9 patients with panic disorder (7 men, 2 women; mean age, 37.4 +/- 13.2 y) and 11 control subjects (11 men; mean age, 37.6 +/- 9.3 y). Early (30 min) and delayed (4 h) planar images were taken after the injection of 111 MBq (123)I-MIBG. The mean counts in the whole heart and the mediastinum were obtained from the early and delayed images to calculate the heart-to-mediastinum count ratios (H/M ratios) and the myocardial washout rate. RESULTS: The (123)I-MIBG H/M ratios of the patients with panic disorder were 1.80 +/- 0.16 for the early images and 1.86 +/- 0.30 for the delayed images, which were significantly lower than those of the control subjects (2.15 +/- 0.15 [P = 0.001] and 2.26 +/- 0.21 [P = 0.009], respectively). The (123)I-MIBG washout rate from the heart in the patients with panic disorder (33.8% +/- 6.9%) was significantly higher than that in the control subjects (27.8% +/- 3.5%) (P = 0.02). CONCLUSION: (123)I-MIBG myocardial scintigraphy demonstrated impairment of cardiac sympathetic function in panic disorder. The results suggest that (123)I-MIBG imaging could become a useful tool for analyzing the pathophysiology of panic disorder.