Postmortem computed tomography imaging of negative pressure pulmonary edema induced by rice cakes: A case report.

Airway obstruction by foreign bodies or laryngospasms often results in negative pressure pulmonary edema (NPPE). NPPE can develop despite the removal of airway obstruction. This is well-known among clinicians, particularly anesthesiologists, emergency physicians, pediatricians, and radiologists. Computed tomography (CT) features of NPPE include diffuse central ground-glass opacities and thickening of the bronchovascular bundles and bronchial walls. NPPE can also occur after strangulation or smothering with a plastic bag, and is sometimes fatal. Nevertheless, no reports of NPPE are available in forensic journals, and forensic practitioners may not be dedicating the necessary attention to this condition. Recently, the use of postmortem CT as an auxiliary imaging modality for autopsies has increased among forensic institutions in Japan. Understanding the mechanisms and CT findings of NPPE will be useful for forensic practitioners. Herein, we present a case wherein the postmortem CT image revealed NPPE resulting from the obstruction of the airway induced by rice cakes.

Rare atlas fracture detected using postmortem computed tomography: A case report.

We report the autopsy of a traffic accident victim with a rare atlas fracture. The deceased was 52-year-old man found dead on the road because of a traffic accident. We performed a postmortem computed tomography and an autopsy on the body. The sagittal reformation image of postmortem computed tomography showed a vertically separated anterior arch of atlas, suggesting a "horizontal fracture." Therefore, we assumed that cervical hyperextension may have been one of the forces that affected him during the accident. Minor spinal cord injury was also noted. In this case, postmortem computed tomography played an important role in detecting the spinal cord injury, considering the mechanism of the traffic accident, and supported the autopsy.

Magnetic resonance voiding cystourethrography (MRVCUG): a potential alternative to standard VCUG.

PURPOSE: To evaluate the accuracy and feasibility of magnetic resonance voiding cystourethrography (MRVCUG), with or without contrast medium, in detecting vesicoureteral reflux (VUR) by comparison with conventional voiding cystourethrography (VCUG). MATERIALS AND METHODS: Seventy-five patients underwent a series of 55 indirect MRVCUG (I-MRVCUG) and 61 direct MRVCUG (D-MRVCUG) between 2003 and 2009. We retrospectively compared the results from I-MRVCUG and D-MRVCUG with those from VCUG on 150 kidney-ureter units. Ratios of successful completion of the two types of MRVCUG were analyzed in 116 examinations according to sex, age, and among the two groups, with or without sedation. RESULTS: D-MRVCUG was superior to I-MRVCUG in detecting VUR (sensitivity: 96.8% vs. 76.9%; specificity: 96.3% vs. 88.7%; agreement: 96.6% vs. 83.7%; kappa: 0.83 [95% confidence interval (CI): 0.72, 0.94] vs. 0.55 [95% CI: 0.41, 0.69]). The overall ratio of successful completion of the two types of MRVCUG was 76.7% (89/116): there was no significant difference between I-MRVCUG and D-MRVCUG. The successful completion rate was significantly lower in MRVCUG in toddlers compared with preschoolers, infants, schoolchildren, and adults (P < 0.001). CONCLUSION: The two types of MRVCUG (I-MRVCUG and D-MRVCUG) are promising tests without radiation exposure. Both I-MRVCUG and D-MRVCUG are feasible for children except for toddlers.

Embolization materials made of gelatin: comparison between Gelpart and gelatin microspheres.

PURPOSE: The object of this study was to assess the level of embolization in the embolized artery and the degradation period of these two embolic agents in the renal arteries using rabbit models. MATERIALS AND METHODS: The renal artery was embolized using 5 mg of gelatin microspheres (GMSs; diameter, 35-100 mum; group 1) or 1 mg of Gelpart (diameter, 1 mm; group 2). For each group, angiographies were performed on two kidneys immediately after the embolic procedure and on days 3, 7, and 14 after embolization. This was followed by histopathological examinations of the kidneys. RESULTS: Follow-up angiograms on each day revealed the persistence of poorly enhanced wedge-shaped areas in the parenchymal phase in all cases. In group 1, four of six cases showed poorly enhanced small areas in the follow-up angiograms. In group 2, all cases showed poorly enhanced large areas. In the histopathological specimens, it was observed that immediately after embolization, the particles reached the interlobular arteries in group 1 and the interlobar arteries in group 2. In all cases in group 1, the particles were histologically identified even on day 14. In one case in group 2 on day 14, the particles were not identified. CONCLUSION: In conclusion, although GMSs and Gelpart were similar in the point of gelatin particles, the level of embolization and the degradation period were different between GMSs and Gelpart.

An initial clinical study on the efficacy of cisplatin-releasing gelatin microspheres for metastatic liver tumors.

PURPOSE: To evaluate the antitumor effect and side effects of cisplatin-releasing gelatin microspheres (Cis-GMSs) for metastatic liver tumors. METHODS: Cis-GMSs that degraded over 14 days were employed. The subjects comprised a total of nine cases. Transcatheter hepatic artery embolization (TAE) using Cis-GMSs (Cis-GMSs-TAE) was performed 13 times in total. Six cases, each containing one to five tumors in a single segment to an entire lobe were treated by Cis-GMSs-TAE. In the remaining three cases with six or more metastatic liver tumors, the right and left lobes were treated by Cis-GMSs-TAE at a 2-week interval. RESULTS: There were two complete response (CR), one partial response (PR) and six stable disease (SD) cases. The response rate was 33.3%. The average rate of reduction in tumor diameter was 32%. Disappearance of metastatic liver tumors was observed in only two of the nine cases. As for side effects and complications, post-embolization syndrome was observed in eight cases, but no severe complications such as cholangitis or liver abscess were observed. CONCLUSION: Considering the mild side effects by Cis-GMSs-TAE, it is suggested that Cis-GMSs-TAE should be tried at least once as topical therapy for metastatic liver tumors when the response to systemic chemotherapy and other treatments is not satisfactory.

Imaging of pulmonary emphysema: a pictorial review.

The term 'emphysema' is generally used in a morphological sense, and therefore imaging modalities have an important role in diagnosing this disease. In particular, high resolution computed tomography (HRCT) is a reliable tool for demonstrating the pathology of emphysema, even in subtle changes within secondary pulmonary lobules. Generally, pulmonary emphysema is classified into three types related to the lobular anatomy: centrilobular emphysema, panlobular emphysema, and paraseptal emphysema. In this pictorial review, we discuss the radiological--pathological correlation in each type of pulmonary emphysema. HRCT of early centrilobular emphysema shows an evenly distributed centrilobular tiny areas of low attenuation with ill-defined borders. With enlargement of the dilated airspace, the surrounding lung parenchyma is compressed, which enables observation of a clear border between the emphysematous area and the normal lung. Because the disease progresses from the centrilobular portion, normal lung parenchyma in the perilobular portion tends to be preserved, even in a case of far-advanced pulmonary emphysema. In panlobular emphysema, HRCT shows either panlobular low attenuation or ill-defined diffuse low attenuation of the lung. Paraseptal emphysema is characterized by subpleural well-defined cystic spaces. Recent topics related to imaging of pulmonary emphysema will also be discussed, including morphometry of the airway in cases of chronic obstructive pulmonary disease, combined pulmonary fibrosis and pulmonary emphysema, and bronchogenic carcinoma associated with bullous lung disease.

Quantitative assessment of arterial stiffness by multiphase analysis in retrospectively electrocardiogram-gated multidetector row computed tomography: comparison between patients under chronic hemodialysis and age-matched controls.

PURPOSE: To determine the feasibility of assessment of arterial stiffness with multiphase analysis of data sets of retrospectively electrocardiogram (ECG)-gated multidetector row computed tomography (MDCT) coronary angiography by comparing wall stiffness of the descending aorta between patients under chronic hemodialysis and age-matched controls undergoing imaging for by-pass graft. MATERIALS AND METHODS: We retrospectively assessed 33 patients composed of 10 hemodialysis patients and 23 age-matched control subjects, who underwent MDCT to evaluate the coronary arterial lesions and pulse wave velocity (PWV) measurement. Scan data were reconstructed at 25 phases between 0% and 96% of the R-R intervals with an increment of 4%. Pixel-based measurements of arterial dimensions were performed at 1 cross-section of the descending aorta in a transaxial plane including the aortic valve at its widest. Aortic distensibility (AD) was calculated as follows: AD = (maximal dimension -- minimal dimension)/minimal dimension x pulse pressure. Comparison in the AD was performed between the hemodialysis patients and control subjects. Correlation between the AD and PWV were assessed separately in the patients under hemodialysis and age-matched controls. RESULTS: AD was significantly smaller in patients under hemodialysis than in age-matched controls. The square of PWV correlated better with the inverse of the AD in the control subjects compared to patients on hemodialysis. CONCLUSION: Multiphase analysis in ECG-gated MDCT enables us to assess stiffness of the descending aorta objectively and noninvasively.

Detection of mediastinal and hilar lymph nodes by 16-row MDCT: is contrast material needed?

PURPOSE: To retrospectively evaluate whether contrast administration is necessary in the detection of mediastinal and hilar lymph nodes when thin slice axial and coronal MDCT images are used. MATERIALS AND METHOD: This study was approved by our Institutional Review Board, informed consent was not required. Thirty-five patients who needed a chest CT (0.75 mm x 16) for various reasons were included. Four different image sets were reconstructed for each patient: non-enhanced axial (N-Ax), non-enhanced coronal MPR (N-Co), enhanced axial (E-Ax) and enhanced coronal MPR (E-Co). All the images were 1mm thick and interval. Two board-certified chest radiologists independently evaluated whether a lymph node with a short diameter, larger than 5mm, existed in each nodal station of the mediastinum and hilum. Two different board-certified chest radiologists assessed all four image sets together and established a reference standard by consensus. Interobserver agreement between the two readers was assessed by kappa statistics. Accuracy was calculated on each image set and compared to each other by McNemar's test. RESULTS: A total of 211 nodal stations, including 113 mediastinal and 98 hilar, were defined to be present and this was the reference standard. Except for N-Ax, the kappa values were within moderate to substantial (0.53-0.81). The accuracy for hilar nodes detection was significantly higher for the contrast enhanced images both in the axial (p<0.001) and coronal (p<0.01) data sets. The addition of contrast material did not significantly increase accuracy for the detection of mediastinal nodes (axial: p=0.542, coronal p=0.727). CONCLUSION: Contrast administration is recommended in the detection of hilar lymph nodes both on axial and MPR views, however, for assessment of mediastinal lymph nodes its contribution is low.

Gelatin microspheres: initial clinical experience for the transcatheter arterial embolization.

PURPOSE: The purpose of this study is to evaluate the embolization effects of gelatin microspheres (GMSs) when used as an embolic material for transcatheter arterial embolization (TAE) for several organs. MATERIALS AND METHODS: We prepared GMSs that dissolves in 5 days in extravasuclar tissue. GMSs were used in five cases in total, four cases with multiple liver tumors and one case with a pelvic bone tumor. RESULTS: In all five cases, it was possible to treat the targeted tumors by TAE with GMSs. In the contrast-enhanced CT performed 2-4 weeks later, the embolized tumors did not show an enhancement effect. Passage of GMSs in the microcatheter was excellent. CONCLUSION: GMSs showed sufficient potential to be used as an embolic material.

Assessment of diaphragmatic motion after lung resection using magnetic resonance imaging.

PURPOSE: The aim of this study was to assess quantitatively the impairment of diaphragmatic motion after lung resection, with special reference to the location of the resected lobe, duration of the postoperative period, and patient posture. We used magnetic resonance imaging to make the assessments. MATERIALS AND METHODS: In 44 patients (29 men, 15 women; mean age 62.2 years) with lung cancer, diaphragmatic motion was measured during maximum deep, slow breathing using a spoiled gradient-recalled echo sequence before and after lung resection. The study group consisted of 34 patients who were examined using a 1.5-T unit in the supine position and 10 patients using a vertically open 0.5-T unit in both the sitting and supine positions. The influence of surgery site and patient posture on diaphragmatic motion after lung resection was investigated. RESULTS: In all cases after lung resection, diaphragmatic motion on the operated side was significantly decreased (P < 0.001), and that on the nonoperated side was significantly increased (P = 0.045). After left upper lobectomy and right bilobectomy, the diaphragmatic motion on the operated side was significantly decreased (P < 0.001), and that of the other side was significantly increased (P < 0.001). The diaphragmatic motion was not significantly changed after right middle lobectomy. The diaphragmatic motion on the operated side was impaired significantly more (P = 0.035) in the supine position than in the sitting position. CONCLUSION: After lobe resection, diaphragmatic motion was impaired more significantly in the supine than in the sitting position; and it differed according to the location of the resected lobe. The improvement in diaphragmatic function after lobectomy was observed over a period of 3-24 months.

Laser-guided computed tomography puncture system: simulation experiments using artificial phantom lesions and preliminary clinical experience.

PURPOSE: To conduct computed tomography (CT)-guided puncture exactly and safely, we newly developed a laser guiding puncture system that can be used in a commercially available CT scanner. MATERIALS AND METHODS: The laser-guided CT puncture system is built on the CT table with an aluminum frame. Preliminary simulation tests were conducted using two models representing the body and nodular lesions, and puncture procedures were carried out for 15 patients using this system. RESULTS: The mean distance and standard deviation from the center in simulation experiments conducted using this puncture system were 2.95 +/- 1.20 mm for operator A and 3.52 +/- 1.12 mm for operator B. There was no statistically significant difference between the operators (P = 0.40) or the angles (P = 0.32). For five lung biopsy patients, the distance from the target point planned before biopsy to the actual last puncture point was 0-8 mm. For 10 percutaneous vertebroplasty (PVP) patients (two performed in Th11, one in Th12, five in L1, two in L2), the plan before the puncture procedure was to pass the needle through the vertebral pedicle in all cases. The distance between the planned target point and the actual last puncture point was 0-5 mm. CONCLUSION: This system has the potential to accomplish the CT-guided puncture procedure safely and accurately.

Resolution of pulmonary multiplanar reconstruction images from 0.5-mm theoretical isotropic data: a fundamental study using an inflated and fixed lung specimen.

The aim of the present study was to define the resolution of multiplanar reconstruction (MPR) of the lung from "theoretical isotropic data." Using inflated and fixed lung specimens of the pig placed in the chest wall phantom, 0.5-mm isotropic data were obtained with 2 different helical pitches: 1:7 (high-quality mode) or 1:13, (high-speed mode), and 2 different tube currents: 250 mAs (high-tube-current mode) or 100 mAs (low-tube-current mode), with or without overlapping reconstruction. MPRs were created from these axial data. The diameter of the smallest visible pulmonary artery and bronchi of these CT images were measured on the corresponding slices of the specimen. The high-speed and low-tube-current mode significantly degraded the image quality due to increased noise. The smallest visible pulmonary artery and bronchus resolved on MPRs from axial-spiral data with 0.5-mm collimation were approximately 100 micrometer and 1,000 micrometer in diameter, respectively. In conclusion, helical pitch and tube current influence the resolution of MPR of the lung.

Magnetic resonance voiding cystourethrography for vesicoureteral reflux.

PURPOSE: To assess the feasibility of magnetic resonance voiding cystourethrography (MRVCUG) using MR fluoroscopy for evaluation of vesicoureteral reflux (VUR), and its use as a noninvasive alternative to standard VCUG. MATERIALS AND METHODS: A total of 22 MR studies of 16 patients (five months to 41 years old) with primary VUR diagnosed by standard VCUG were evaluated. Six patients underwent MR studies and standard VCUG pre- and postoperatively. MR fluoroscopy was executed with a non-enhanced heavily T2-weighted single-shot fast spin-echo (FSE) sequence. The MR findings were correlated with those obtained by the gold standard, standard VCUG. RESULTS: Of the 44 kidney-ureter units, 20 were refluxing on MRVCUG and 21 were refluxing on standard VCUG. There were one false-positive and two false-negative units. MRVCUG was 90% sensitive with a specificity of 96% for detecting VURs that were calculated based on kidney-ureter units. Two false-negative units were found in mild cases (grade I and II). For the units of grade III, IV, and V (high-grade reflux), MRVCUG detected all of the refluxing renal collecting systems. CONCLUSION: MRVCUG can demonstrate high-grade reflux without ionizing radiation or catheterization.

Multidetector-row computed tomography coronary angiography: optimization of image reconstruction phase according to the heart rate.

BACKGROUND: To optimize the image reconstruction phase of multidetector-row computed tomography (MDCT) coronary angiography according to the heart rate is crucial. METHODS AND RESULTS: Scan data were reconstructed for 10 different phases in 58 sequential patients who underwent 8-row cardiac MDCT. The obtained images were scored and compared in terms of motion artifacts and visibility of the vessels, and moreover, ECG record-based evaluations were added for clarification of the temporal relationships among these 10 phases. In the cases with lower heart rates (<65 beats/min), the best quality images were obtained when the end of the image reconstruction phase was positioned at the peak of the P wave. In some cases with higher heart rates (>65 beats/min), they were obtained in the late systolic period. CONCLUSION: As the heart rate increased, the optimal image reconstruction phase changed from mid diastole to late systole. However, it is recommended to try to decrease the heart rate of patients before data acquisition.

Pluronic F127: application in arterial embolization.

PURPOSE: Pluronic is a substance that is widely used in medical and pharmaceutical fields. In particular, 20% Pluronic F127 solution is a unique substance that is liquid at less than 15 degrees C and gelatinous at 25 to 60 degrees C. In this study, the authors took advantage of the gelation property of Pluronic F127 at human body temperature to simulate embolization and dissolution of the embolism in the renal artery and the superior mesenteric artery (SMA) using a rabbit model. MATERIALS AND METHODS: Four female Japanese rabbits (weight, 2.5-3 kg each) were used. The renal artery was fitted with a 4-F cobra-type catheter and embolized with a 20% Pluronic F127 solution at a temperature of 20 degrees C. The embolic effect was evaluated by angiography immediately after the initial injection and every 15 minutes for 2.5 hours after embolization. After 24 hours, pathologic changes of the renal parenchyma were also evaluated. The embolic effect for SMA and ischemic changes of the intestine were evaluated in the same manner. RESULTS: Angiographic findings showed that Pluronic F127 caused embolization immediately after injection and dissolved in the renal artery and the SMA after 90 to 120 minutes. The pathologic findings showed no ischemic change in the renal parenchyma. Necrosis was not found in the intestine, but focal hemorrhagic changes were extensively present when the gel had dissolved. This suggested that Pluronic F127 dissolved before severe tissue damage could occur. CONCLUSION: Pluronic F127 can potentially be used as a temporary embolic material.

Diaphragmatic motion in the sitting and supine positions: Healthy subject study using a vertically open magnetic resonance system.

PURPOSE: To determine the postural difference of diaphragmatic motion between the sitting and supine positions. MATERIALS AND METHODS: A total of 10 healthy men were examined using a vertically open 0.5-T magnetic resonance (MR) system. A total of 40 sequential MR images were obtained in both the sitting and supine positions during two to five respiratory cycles. The diaphragmatic excursions (DEs) were measured on three diaphragmatic points of six sagittal planes for both positions. The differences in DEs between the anterior and posterior parts of the diaphragm were also determined. RESULTS: DEs in the supine position were significantly greater than those in the sitting position at 15 of the 18 points. In five of the six sagittal planes, the difference of DE between posterior and anterior points was significantly larger in the supine position than in the sitting position. CONCLUSION: Diaphragmatic movement in the supine position is greater than that in the sitting position, especially in the posterior part of the diaphragm.

Visual assessment of coronary artery stenosis with electrocardiographically-gated multislice computed tomography.

BACKGROUND: With faster image acquisition times and thinner slice widths, multislice detector computed tomography (MSCT) allows visualization of human coronary arteries. Significantly improved image quality, with high resolution and new software for three-dimensional post-processing, has made noninvasive examination of the cavities within human body possible. OBJECTIVE: The aims of this study are to evaluate the diagnostic accuracy of ECG-gated MSCT for the detection of significant coronary artery stenosis and occlusions. METHODS: In 25 patients (19 male and 6 female aged 65+/-9 years) with suspected obstructive coronary artery disease, ECG-gated MSCT angiography was performed with an 8-slice MSCT scanner. Visual coronary arteries were simulated in three coronary arteries. Conventional coronary angiographies were performed in all patients. And coronary lesions in MSCT were estimated by two observers, who did not know the results of the coronary angiography. RESULTS: Current MSCT allows visual coronary artery with good image quality. The overall sensitivity for diagnosing significant coronary stenosis were 75.0%, the specificity was 95.6%. The positive and negative predictive values were 84.9 and 92.2%, respectively. The accuracy of MSCT for detecting coronary stenosis is the highest in the left main tranck and left anterior descending coronary artery, and lowest in the circumflex coronary artery. CONCLUSION: MSCT was feasible for the detection of coronary artery stenosis.