Naoki Takahashi

Comparison of18FDG-PET with99mTc-HMDP scntigraphy for the detection of bone metastases in patients with breast cancer

ObjectiveBone is one of the most common sites of metastasis in breast cancer patients. Although bone scintigraphy is widely used to detect metastatic breast cancer, the usefulness of18FDG-PET for detecting bone metastasis has not been clearly evaluated. The purpose of this study was to compare the diagnostic accuracy of18FDG-PET with bone scintigraphy in detecting bone metastasis in breast cancer patients.MethodsForty-four women aged 35 to 81 years (mean, 56 years) with breast cancer were examined in this study. Both18FDG-PET and bone scintigraphy were performed for each patient with 0-69 day intervals (mean, 11.5 days). The results of each image interpretation were compared retrospectively. Whole-body bones were classified into 9 anatomical regions. Metastases were confirmed at 45/187 regions in 14 patients by bone biopsy or clinical follow-up including other imaging techniques for a period of at least 6 months afterwards.ResultsOn a region basis, the sensitivity, specificity, and accuracy of18FDG-PET were 84%, 99% and 95%, respectively. Although these results were comparable to those of bone scintigraphy, the combination of18FDG-PET and bone scintigraphy improved the sensitivity (98%) and accuracy (97%) of detection. False negative lesions of bone scintigraphy were mostly bone marrow metastases and those of18FDG-PET were mostly osteoblastic metastases.18FDG-PET was superior to bone scintigraphy in the detection of osteolytic lesions (92% vs. 73%), but inferior in the detection of osteoblastic lesions (74% vs. 95%).ConclusionsThis study shows that18FDG-PET tends to be superior to bone scintigraphy in the detection of osteolytic lesions, but inferior in the detection of osteoblastic lesions.18FDG-PET should play a complementary role in detecting bone metastasis with bone scintigraphy.

Computer-Aided Nodule Detection on Digital Chest Radiography: Validation Test on Consecutive T1 Cases of Resectable Lung Cancer

PurposeTo evaluate the usefulness of a commercially available computer-assisted diagnosis (CAD) system on operable T1 cases of lung cancer by use of digital chest radiography equipment.Materials and MethodsFifty consecutive patients underwent surgery for primary lung cancer, and 50 normal cases were selected. All cancer cases were histopathologically confirmed T1 cases. All normal individuals were selected on the basis of chest computed tomography (CT) confirmation and were matched with cancer cases in terms of age and gender distributions. All chest radiographs were obtained with one computed radiography or two flat-panel detector systems. Eight radiologists (four chest radiologists and four residents) participated in observer tests and interpreted soft copy images by using an exclusive display system without and with CAD output. When radiologists diagnosed cases as positives, the locations of lesions were recorded on hard copies. The observers’ performance was evaluated by receiver operating characteristic analysis.ResultsThe overall detectability of lung cancer cases with CAD system was 74% (37/50), and the false-positive rate was 2.28 (114/50) false positives per case for normal cases. The mean Az value increased significantly from 0.896 without CAD output to 0.923 with CAD output (P = 0.018). The main cause of the improvement in performance is attributable to changes from false negatives without CAD to true positives with CAD (19/31, 61%). Moreover, improvement in the location of the tumor was observed in 1.5 cases, on average, for radiology residents.ConclusionThis CAD system for digital chest radiographs is useful in assisting radiologists in the detection of early resectable lung cancer.

Pulmonary lesions associated with visceral larva migrans due to Ascaris suum or Toxocara canis : Imaging of six cases

OBJECTIVEnThe objective of our study was to evaluate chest radiographic and CT findings of patients with pulmonary lesions associated with visceral larva migrans due to Ascaris suum or Toxocara canis. CT investigation was focused on the location, size, contour, and internal features of the lesions; migration of lesions; mediastinal lymphadenopathy; and pleural effusion.nnnCONCLUSIONnPulmonary visceral larva migrans appears on CT as multifocal subpleural nodules with halo or ground-glass opacities and ill-defined margins.

Multi-detector row computed tomographic angiography in pediatric heart transplant recipients: Initial observations.

Background. The purpose of this study was to assess the feasibility and limitation of multi-detector row computed tomographic (MDCT) imaging for evaluating coronary arteries in pediatric heart transplant patients. Methods. Coronary MDCT angiography was performed in eight pediatric heart transplant recipients. The presence of coronary calcification was evaluated. Luminal changes of the visualized coronary segments on MDCT images were compared with catheter angiographic findings and intravascular ultrasound. Results. Coronary calcification was present in one patient who had severe coronary arteriopathy documented by intravascular ultrasound. In 48 coronary segments visualized on MDCT images, 33, 7, and 4 segments each had normal, luminal irregularities, and moderate stenoses, respectively, which were confirmed by catheter angiography. Twelve coronary segments could not be assessed because of severe motion artifacts. Image quality degradation was more pronounced in patients with higher heart rates. Conclusions. Noninvasive MDCT angiography is promising but requires further technical improvement to evaluate coronary arteries in pediatric heart transplant patients.

Performing cardiac MR imaging: an overview

Because of the enormous economic and social impact of cardiovascular disease in the United States, there is a need for improved noninvasive diagnosis. Cardiac MR imaging is a versatile, comprehensive technique for assessing cardiac morphology and function. With an understanding of cardiac anatomy and physiology as well as MR physical principles, cardiac MR imaging can be performed and play an important role in patient management.

MR evaluation of intrapulmonary hematoma.

We report a case of circumscribed intrapulmonary hematoma, in which MR findings were useful in establishing the diagnosis. It is usually easy to make a diagnosis of intrapulmonary hematoma using conventional methods, when clinical history of trauma and regression of the mass can be observed on serial radiography. However, in this case the mass remained almost unchanged 4 months after trauma on chest radiography and CT. Magnetic resonance revealed a hyperintense mass with an even higher signal rim on T1-weighted imaging and an irregular hyperintense mass on T2*-weighted imaging. We made a diagnosis of pulmonary hematoma based on these MR findings. Follow-up chest radiography and CT taken 1 year after the injury, revealed a substantial decrease in the size of the mass, which confirmed the diagnosis. As in this case, some intrapulmonary hematomas regress very slowly or may even increase in size, and diagnosis can be difficult with conventional methods. In such cases, MRI can be helpful.

Granular cell tumor presenting as an intradural extramedullary tumor

Granular cell tumor (GCT) is an uncommon benign tumor, which is thought to originate from a Schwann cell. GCT may involve any part of the body, but in our knowledge, there has been only one previous report of GCT, which arose in the intradural extramedullary space of the spine. We report a case of GCT, which occurred in the intradural extramedullary space.

A new soldier beetle Malthinellus exiguus sp. nov. (Coleoptera: Cantharidae) from the Ryukyus in southwestern Japan, with a key to Japanese species

Malthinellus exiguus sp. nov., from the central Ryukyus in the southwestern part of Japan is described and illustrated. An identification key to the Japanese species and the checklist of the known species of Malthinellus are provided.

Discovery of a new species of the brachyelytrous net-winged beetle genus Alyculus (Coleoptera: Lycidae) from Peninsular Malaysia.

The net-winged beetle genus Alyculus Kasantsev is reported from Peninsular Malaysia for the first time and a new species, A. malaypeninsularis sp. nov., is described and illustrated. An expanded identification key to Alyculus males is provided and the biology and distribution of the species are discussed.