Junpei Ikezoe

High-resolution CT findings of lung disease in patients with polymyositis and dermatomyositis.

The purpose of this study was to determine the type and distribution of interstitial lung disease seen in patients with polymyositis and dermatomyositis, using high-resolution computed tomography (HRCT). The presence and distribution of high-resolution CT findings were retrospectively evaluated in 25 patients with polymyositis/dermatomyositis. In 14 patients, a pathological diagnosis of pulmonary disease was obtained. Three lung specimens were also studied. Results showed that 23 patients had abnormal HRCT showing the following abnormalities: ground glass opacities (92%), linear opacities (92%), irregular interfaces (88%), airspace consolidation (52%), parenchymal micronodules (28%), and honeycombing (16%). A relatively high prevalence of airspace consolidation (52%) and a low prevalence of honeycombing (16%) were observed. Two patients with extensive consolidation proved to have diffuse alveolar damage; eight patients with either subpleural band-like opacities (n = 5) and/or airspace consolidation (n = 7) had bronchiolitis obliterans organizing pneumonia; four patients with honeycombing had usual interstitial pneumonitis. We conclude that HRCT findings in patients with polymyositis/dermatomyositis are nonspecific. However, a high prevalence of airspace consolidation and a low prevalence of honeycombing were observed. Predominant HRCT patterns are suggestive of the pathologic processes occurring in polymyositis/dermatomyositis.

Circulating KL-6 levels in patients with drug induced pneumonitis

Background: The circulating level of KL-6/MUC1 is a sensitive marker for various interstitial lung diseases. Previous case reports have suggested that KL-6 may also be increased in some patients with drug induced pneumonitis. A study was undertaken to determine whether serum KL-6 could be a marker for particular types of drug induced pneumonitis. Methods: The findings of high resolution computed tomographic (HRCT) chest scans of 30 patients with drug induced pneumonitis were reviewed separately by two independent observers. The pneumonitis was classified into four predominant patterns: widespread bilateral consolidation (diffuse alveolar damage, DAD; n=7), fibrosis with or without consolidation (chronic interstitial pneumonia, CIP; n=11), consolidation without fibrosis (bronchiolitis obliterans organising pneumonia or eosinophilic pneumonia, BOOP/EP; n=8), and diffuse ground glass opacities without fibrosis (hypersensitivity pneumonitis, HP; n=4). Serum KL-6 levels were measured by a sandwich enzyme linked immunosorbent assay. Results: The overall sensitivity of serum KL-6 in detecting drug induced lung disease was 53.3%, which was lower than its sensitivity in detecting other interstitial lung diseases. However, the KL-6 level was increased in most patients with a DAD or CIP pattern (16/18; 88.9%) and was closely correlated with their clinical course. In contrast, serum KL-6 levels were within the normal range in all patients with a BOOP/EP or HP pattern. Conclusions: Particular patterns detected by HRCT scanning, such as DAD and CIP but not the BOOP/EP or HP patterns, are associated with increased circulating KL-6 levels in drug induced pneumonitis. Serum KL-6 levels may reflect the clinical activity of the particular disorders.

Determination of arterial input function using fuzzy clustering for quantification of cerebral blood flow with dynamic susceptibility contrast-enhanced MR imaging

An accurate determination of the arterial input function (AIF) is necessary for quantification of cerebral blood flow (CBF) using dynamic susceptibility contrast‐enhanced magnetic resonance imaging. In this study, we developed a method for obtaining the AIF automatically using fuzzy c‐means (FCM) clustering. The validity of this approach was investigated with computer simulations. We found that this method can automatically extract the AIF, even under very noisy conditions, e.g., when the signal‐to‐noise ratio is 2. The simulation results also indicated that when using a manual drawing of a region of interest (ROI) (manual ROI method), the contamination of surrounding pixels (background) into ROI caused considerable overestimation of CBF. We applied this method to six subjects and compared it with the manual ROI method. The CBF values, calculated using the AIF obtained using the manual ROI method [CBF(manual)], were significantly higher than those obtained with FCM clustering [CBF(fuzzy)]. This may have been due to the contamination of non‐arterial pixels into the manually drawn ROI, as suggested by simulation results. The ratio of CBF(manual) to CBF(fuzzy) ranged from 0.99–1.83 [1.31 ± 0.26 (mean ± SD)]. In conclusion, our FCM clustering method appears promising for determination of AIF because it allows automatic, rapid and accurate extraction of arterial pixels. J. Magn. Reson. Imaging 2001;13:797–806.

Chronic eosinophilic pneumonia: evolution of chest radiograms and CT features.

Objective Our object is to describe and compare the findings on plain chest radiographs and CT scans in patients with chronic eosinophilic pneumonia of varying duration, as judged by their clinical history. Materials and Methods We retrospectively reviewed the initial chest radiographs and initial CT scans that were obtained before treatment with corticosteroid in 17 patients with pathologically proven or clinically diagnosed chronic eosinophilic pneumonia. Results Eleven of the 17 patients showed predominantly peripheral patchy or confluent consolidation with or without ground-glass opacities on chest radiography. Sixteen patients, on the other hand, showed various types of abnormalities with peripheral predominance on CT. The seven patients in whom the initial CT was performed within 1 month after the onset of symptoms had dense confluent consolidation (7/7) with or without ground-glass opacities. When the initial CT was performed 1–2 months after onset of symptoms, inhomogeneous patchy consolidation or nodules (5/7) or ground-glass opacities (2/7) were observed. When the initial CT was performed >2 months after the onset of symptoms, streaky or band-like opacities (1/3) or lobar atelectasis (1/3) was seen. Conclusion Patients with chronic eosinophilic pneumonia show an evolution of CT features at varying time intervals after the onset of disease.

Demonstration of Acute Myocardial Infarction by Subsecond Spiral Computed Tomography Early Defect and Delayed Enhancement

Case 1. An 85-year-old woman was hospitalized after 3 hours of chest pain and dyspnea. She was diagnosed as having anteroseptal acute myocardial infarction (AMI) from her symptoms and the ECG (elevated ST-T in leads I, aV L, and V1 through V3). She had to wait for emergency coronary angiography (CAG), because another patient with AMI was occupying the catheter laboratory. During her standby status, contrast-enhancement spiral CT was performed (Figure 1a). Total occlusion of the left anterior descending coronary artery (segment 7) was observed by the CAG. Six days after successful direct PTCA, plain and Gd-enhancement T1weighted MRI was performed (Figure 1b). Three days after the PTCA, dual SPECT withTc-pyrophosphate (hot scan) and Tl was performed (Figure 1c). Seven days after the PTCA, serial dynamic spiral CT data were obtained at 50 seconds, 3 minutes, and 8 minutes at injection of the contrast material (1.2 mL/s, 100 mL total) (Figure 2). Case 2. A 49-year-old man presented with chest pain. He was diagnosed as having inferior AMI from his symptoms and the ECG (elevated ST-T in leads II, III, aV F, and V6). CAG demonstrated 99% stenosis of the right coronary artery (segment 4PD). Two days after successful direct PTCA, contrastenhancement spiral CT was performed (Figure 3a). Three days after the PTCA, dual SPECT withTc-pyrophosphate (hot scan) andTl was performed (Figure 3b).Case 1. An 85-year-old woman was hospitalized after 3 hours of chest pain and dyspnea. She was diagnosed as having anteroseptal acute myocardial infarction (AMI) from her symptoms and the ECG (elevated ST-T in leads I, aVL, and V1 through V3). She had to wait for emergency coronary angiography (CAG), because another patient with AMI was occupying the catheter laboratory. During her standby status, contrast-enhancement spiral CT was performed (Figure 1a⇓). Total occlusion of the left anterior descending coronary artery (segment 7) was observed by the CAG. Six days after successful direct PTCA, plain and Gd-enhancement T1-weighted MRI was performed (Figure 1b⇓). Three days after the PTCA, dual SPECT with 99m …

Prognostic Value of Dipyridamole-Thallium Myocardial Scintigraphy in Patients With Kawasaki Disease

BACKGROUNDnAlthough coronary artery lesions are critical complications of Kawasaki disease, their long-term outcome is still unclear. It is sometimes difficult to monitor progressive changes from aneurysms to stenotic lesions because coronary angiography (CAG) cannot be repeated very often, especially in infants. Our prospective study was designed to evaluate the prognostic value of dipyridamole-thallium single-photon-emission CT (SPECT) in the long-term follow-up of patients with Kawasaki disease.nnnMETHODS AND RESULTSnOf 459 consecutive patients with Kawasaki disease, coronary aneurysms were detected in 90 cases by echocardiography during the acute stage. After paired studies of selective CAG and SPECT were conducted, all patients were followed up and monitored for the occurrence of any cardiac events for > or =8 years. During the follow-up interval, there were 15 cardiac events (1 death, 5 infarctions, 2 coronary artery bypass graft operations, and 7 occurrences of unstable angina). Of patients who had some event, thallium redistribution was found on SPECT in 14 (93%, P<0.001). Of the various clinical and scintigraphic image variables, the presence of thallium redistribution was the best multivariate independent predictor of a late cardiac event (chi2=57.8, P<0.0001). The number of aneurysms detected on CAG added minimal statistical improvement to the model (chi2=1.9, P=0.0009).nnnCONCLUSIONSnDipyridamole-thallium SPECT is safely performed and is useful and important for risk stratification in the long-term follow-up of patients with Kawasaki disease.

Subluxation of the patella: evaluation of patellar articular cartilage with MR imaging

In patients with subluxation of the patella, injury of the patellar articular cartilage is frequently observed, and correct evaluation of this cartilage injury is extremely important for the management of these patients. Magnetic Resonance (MR) studies were performed on 102 patellofemoral (PF) joints of 51 patients with subluxation of the patella and 20 PF joints of 10 healthy volunteers. In 77 of the 102 PF joints with subluxation, arthroscopy and/or operation were performed. MR images were obtained with spin-echo and FLASH sequences, and para-axial images were obtained. We retrospectively analysed the MR findings of the 77 joints with special attention to the surface and thickness of the cartilage, and classified them into four grades. These MR grades were compared with the grades on arthroscopy, and the following results were obtained: MR grade 0, normal cartilage (n = 27, sensitivity 90.9%, specificity 74.2%); MR grade 1, thickening of the cartilage (n = 24, sensitivity 50%, specificity 89.1%); MR grade 2, surface irregularity of the cartilage (n = 20, sensitivity 85%, specificity 94.7%); MR grade 3, loss of the cartilage (n = 6, sensitivity 100%, specificity 100%). Although the early changes observed by arthroscopy were underestimated from the MR images, MR imaging proved to be extremely useful for evaluating moderately or advanced patellar cartilage injury.

In vitro evaluation of normal and abnormal lungs with ultra-high-resolution CT.

Synchrotron radiation microtomography is a new technique with high directionality of a synchrotron radiation beam and a high-resolution detector array. In this study, we estimated the visualization of the peripheral human lung structure with an ultra-high-resolution computed tomography (CT) system, the synchrotron radiation CT. The synchrotron radiation CT system uses the bending magnet beamline emitted from the 8.0 GeV electron storage ring. Six lung specimens were obtained at autopsy: 3 normal, 1 cellular alveolitis, 1 diffuse alveolar damage, and 1 pulmonary hemorrhage. Each specimen was cut down to a cylindrical sample with 6-mm diameter and 15- to 25-mm height. The synchrotron radiation CT images of these lung samples were obtained using the ultra-high-resolution image detector system with a charge coupled device (CCD) array detector (1024 × 1024 pixels with 12 × 12 &mgr;m2 pixel size). After that, the sample specimens were sliced to 200 &mgr;m (micrometer) thickness, and were observed with a stereomicroscope and by contact radiography. Finally, approximately 10-&mgr;m thick microscopic images were obtained and compared with the synchrotron radiation CT images. The synchrotron radiation CT could depict the peripheral lung including peripheral airways, airspaces, and alveolar walls individually. Each finding in the 3 disease processes seen on the synchrotron radiation CT images correlated well with the microscopic findings. The synchrotron radiation CT allows microtomographic imaging of human lung specimens with ultra high-spatial resolution (12 &mgr;m) on a level approaching that of conventional histopathology, without sectioning.

Metastatic pulmonary calcification: early detection by high-resolution CT.

A 41-year-old man with a renal transplant was admitted with cough, fever, and dyspnea. Although chest radiography was normal, high-resolution CT demonstrated small hazy round opacities in the centrilobular regions throughout both lungs. The biopsy specimen revealed metastatic calcification in the alveolar septa and the walls of the bronchioles and arterioles. High-resolution CT may be useful for the early detection of metastatic pulmonary calcification when plain radiography is negative and therapy has the potential to reverse the process.

Automated seeded region growing algorithm for extraction of cerebral blood vessels from magnetic resonance angiographic data

Magnetic resonance angiography (MRA) has currently played a useful clinical role as a noninvasive method of surveying vascular anatomy. In this study, we developed an automated seeded region growing algorithm for extraction of blood vessels from MRA data. In the conventional region growing algorithm, the user must manually place a seed point within a large blood vessel and also input the segmentation threshold. Furthermore, these processes must be repeated with a different set of seeds and threshold until the satisfactory results are obtained. Thus, this method is time-consuming and the results obtained by this method are highly subjective to the user. With our algorithm, binary images were firstly generated by thresholding the original MRA data to roughly obtain the images of blood vessels, and then the skeletons were generated from these images using the thinning algorithm based on the Euclidean distance transformation. Finally, these skeletons were used as the seeds for region growing. Our method could extract blood vessels automatically and stably, and the segmentation leakage could be largely suppressed. In conclusion, our automated seeded region growing algorithm appears to be useful for extracting and displaying blood vessels in a three-dimensional manner.