Hisashi Kamiya

Measurement of Focal Ground-glass Opacity Diameters on CT Images: Interobserver Agreement in Regard to Identifying Increases in the Size of Ground-Glass Opacities

PURPOSE To evaluate interobserver agreement in regard to measurements of focal ground-glass opacities (GGO) diameters on computed tomography (CT) images to identify increases in the size of GGOs. MATERIALS AND METHODS Approval by the institutional review board and informed consent by the patients were obtained. Ten GGOs (mean size, 10.4 mm; range, 6.5-15 mm), one each in 10 patients (mean age, 65.9 years; range, 58-78 years), were used to make the diameter measurements. Eleven radiologists independently measured the diameters of the GGOs on a total of 40 thin-section CT images (the first [n = 10], the second [n = 10], and the third [n = 10] follow-up CT examinations and remeasurement of the first [n = 10] follow-up CT examinations) without comparing time-lapse CT images. Interobserver agreement was assessed by means of Bland-Altman plots. RESULTS The smallest range of the 95% limits of interobserver agreement between the members of the 55 pairs of the 11 radiologists in regard to maximal diameter was -1.14 to 1.72 mm, and the largest range was -7.7 to 1.7 mm. The mean value of the lower limit of the 95% limits of agreement was -3.1 ± 1.4 mm, and the mean value of their upper limit was 2.5 ± 1.1 mm. CONCLUSION When measurements are made by any two radiologists, an increase in the length of the maximal diameter of more than 1.72 mm would be necessary in order to be able to state that the maximal diameter of a particular GGO had actually increased.

CT Scans of the Chest in Carriers of Human T-cell Lymphotropic Virus Type 1 : Presence of Interstitial Pneumonia

RATIONALE AND OBJECTIVES To evaluate pulmonary findings on computed tomography (CT) scans in carriers of human T-lymphotropic virus type 1 (HTLV-1). MATERIALS AND METHODS This retrospective study was approved by the Institutional Review Board at each institution, and informed consent was waived. Patients who were diagnosed with adult T-cell lymphoma/leukemia or collagen vascular disease were excluded from the study. Chest CT of 106 HTLV-1 carriers (54 females and 52 males; age range 44-94 years) were initially evaluated by two chest radiologists. Assessed CT findings included centrilobular nodules, thickening of bronchovascular bundles, ground-glass opacity, bronchiectasis, interlobular septal thickening, consolidation, honeycombing, crazy-paving appearance, enlarged lymph nodes, pleural effusion, and pericardial effusion. Three chest radiologists secondarily evaluated the CT scans with the abnormal findings to judge the presence of interstitial pneumonia patterns or a bronchiolitis/bronchitis pattern. RESULTS Abnormal CT findings were found in 65 (61.3%) patients, including ground-glass opacity (n = 33), bronchiectasis (n = 28), centrilobular nodules (n = 25), and interlobular septal thickening (n = 19). Honeycombing (n = 5) and crazy-paving appearance (n = 3) were also observed. Based on the CT findings, 10 subjects were diagnosed with interstitial pneumonia (usual interstitial pneumonia pattern, n = 3; nonspecific interstitial pneumonia pattern, n = 5; organizing pneumonia pattern, n = 2; respectively). Twenty subjects were diagnosed with the bronchitis/bronchiolitis pattern. CONCLUSION Although the bronchiolitis/bronchitis pattern is predominant on chest CT in HTLV-1 carriers, the HTLV-1 infection is associated with various interstitial pneumonias.

Adaptive Iterative Dose Reduction Using Three Dimensional Processing (AIDR3D) improves chest CT image quality and reduces radiation exposure.

Objective To assess the advantages of Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D) for image quality improvement and dose reduction for chest computed tomography (CT). Methods Institutional Review Boards approved this study and informed consent was obtained. Eighty-eight subjects underwent chest CT at five institutions using identical scanners and protocols. During a single visit, each subject was scanned using different tube currents: 240, 120, and 60 mA. Scan data were converted to images using AIDR3D and a conventional reconstruction mode (without AIDR3D). Using a 5-point scale from 1 (non-diagnostic) to 5 (excellent), three blinded observers independently evaluated image quality for three lung zones, four patterns of lung disease (nodule/mass, emphysema, bronchiolitis, and diffuse lung disease), and three mediastinal measurements (small structure visibility, streak artifacts, and shoulder artifacts). Differences in these scores were assessed by Scheffes test. Results At each tube current, scans using AIDR3D had higher scores than those without AIDR3D, which were significant for lung zones (p<0.0001) and all mediastinal measurements (p<0.01). For lung diseases, significant improvements with AIDR3D were frequently observed at 120 and 60 mA. Scans with AIDR3D at 120 mA had significantly higher scores than those without AIDR3D at 240 mA for lung zones and mediastinal streak artifacts (p<0.0001), and slightly higher or equal scores for all other measurements. Scans with AIDR3D at 60 mA were also judged superior or equivalent to those without AIDR3D at 120 mA. Conclusion For chest CT, AIDR3D provides better image quality and can reduce radiation exposure by 50%.

Infectious mediastinitis after cardiovascular surgery: role of computed tomography

PurposeThe aim of this study was to evaluate the effectiveness of computed tomography (CT) findings in the diagnosis of mediastinitis after cardiovascular surgery with median sternotomy.Material and methodsA total of 122 patients were divided into two groups: the early group (≤21 days after surgery) and the late group (>21 days after surgery). Among them, six patients were ultimately diagnosed with infectious mediastinitis. CT findings in each patient were evaluated. Mediastinal fluid collections or free gas bubbles were regarded as the primary findings of mediastinitis.ResultsIn the early group, sensitivity and specificity of the primary CT findings were 100% and 39%, respectively. In the late group, the sensitivity was 100% and the specificity 85%. Mediastinal fluid collections were observed in all six patients with mediastinitis.ConclusionMediastinal fluid collections or free gas bubbles are not specific during the early postoperative period. However, after 2 21 days, these observations could be indicative of mediastinitis.

Lung Image Quality with 320-row Wide-volume CT Scans: The Effect of Prospective ECG-gating and Comparisons with 64-row Helical CT Scans

RATIONALES AND OBJECTIVES To evaluate the image quality of 320-row wide-volume (WV) computed tomography (CT) scans in comparison with 64-row helical scans for the lung. MATERIALS AND METHODS The Institutional Review Board of each institution approved this prospective, multicenter study and informed consent was obtained. A total of 73 subjects underwent two types of chest CT, including 320-row WV scans and 64-row helical scans. Both scans used the same tube voltage, tube current, exposure time setting, and slice thickness. The helical scans were not electrocardiogram (ECG)-gated. For the WV scans, prospective ECG-gating was used for 38 subjects, whereas the other 35 subjects did not have ECG-gating. Using a 5-point scale from 1 (nondiagnostic) to 5 (excellent), three blinded observers independently evaluated image quality for five lobes and the lingula. The differences in the scores between WV scans and helical scans were compared using Wilcoxons signed-rank test. RESULTS The WV scans with ECG-gating had significantly higher scores than 64-row helical scans for all lobes and lingula (right lower lobe, P < .01; other lobes and lingula, P < .0001, respectively). The 320-row WV scans without ECG-gating also had significantly higher scores than 64-row helical scans (P < .05), except for nonsignificant differences for the left upper lobe. CONCLUSIONS Lung image quality of ECG-gated WV scans, which do not require any additional radiation exposure, is better than that of non-ECG-gated 64-row helical scans. Non-ECG-gated 320-row WV scans are comparable or slightly superior to non-ECG-gated 64-row helical scans.

Massive ovarian edema with torsion: unusual hemorrhage and the recovery of contrast enhancement

We report a case of massive ovarian edema due to left adnexal torsion. On initial magnetic resonance (MR), unusual hemorrhages were demonstrated as several hypointense areas on T2-weighted images. The lack of contrast enhancement was also observed in the left adnexa. Abdominal pain resolved spontaneously, and then follow-up MR demonstrated the recovery of enhancement and hemorrhages as hyperintense signals on T1-weighted images.

Sub-solid Nodule Detection Performance on Reduced-dose Computed Tomography with Iterative Reduction: Comparison Between 20 mA (7 mAs) and 120 mA (42 mAs) Regarding Nodular Size and Characteristics and Association with Size-specific Dose Estimate

RATIONALE AND OBJECTIVES This study aimed to compare sub-solid nodule detection performances (SSNDP) on chest computed tomography (CT) with Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR 3D) between 7 mAs (0.21 mSv) and 42 mAs (1.28 mSv) in total and in subgroups classified by nodular size, characteristics, and location, and analyze the association of SSNDP with size-specific dose estimate (SSDE). MATERIALS AND METHODS As part of the Area-detector Computed Tomography for the Investigation of Thoracic Diseases Study, a Japanese multicenter research project, 68 subjects underwent chest CT with 120 kV, 0.35 seconds per rotation, and three tube currents: 240 mA (84 mAs), 120 mA (42 mAs), and 20 mA (7 mAs). The research committee of the study project outlined and approved our study protocols. The institutional review board of each institution approved this study. Axial 2-mm-thick CT images were reconstructed using AIDR 3D. Standard reference was determined by CT images at 84 mAs. Four radiologists recorded SSN presence by continuously distributed rating on CT at 7 mAs and 42 mAs. Receiver operating characteristic analysis was used to evaluate SSNDP at both doses in total and in subgroups classified by nodular longest diameter (LD) (≥5 mm), characteristics (pure and part-solid), and locations (ventral, intermediate, or dorsal; central or peripheral; and upper, middle, or lower). Detection sensitivity was compared among five groups of SSNs classified based on particular SSDE to nodule on CT with AIDR 3D at 7 mAs. RESULTS Twenty-two part-solid and 86 pure SSNs were identified. For larger SSNs (LD ≥ 5 mm) as well as subgroups classified by nodular locations and part-solid nodules, SSNDP was similar in both methods (area under the receiver operating characteristics curve: 0.96 ± 0.02 in CT at 7 mAs and 0.97 ± 0.01 in CT at 42 mAs), with acceptable interobserver agreements in five locations. For larger SSNs (LD ≥ 5 mm), on CT at 42 mAs, no significant differences in detection sensitivity were found among the five groups classified by SSDE, whereas on CT with 7 mAs, four groups with SSDE of 0.65 or higher were superior in detection sensitivity to the other group, with SSDE less than 0.65 mGy. CONCLUSIONS For SSNs with 5 mm or more in cases with normal range of body habitus, CT at 7 mAs was demonstrated to have comparable SSNDP to CT at 42 mAs regardless of nodular location and characteristics, and SSDE higher than 0.65 mGy is desirable to obtain sufficient SSNDP.

Pulmonary nodules: a quantitative method of diagnosis by evaluating nodule perimeter difference to approximate oval using three-dimensional CT images.

The purpose of this study was to investigate whether maximum nodule perimeter to the approximate oval could discriminate benign nodules from malignancy. Measurement of maximum nodule perimeter difference to the approximate oval was performed using volume-rendering images of three directions of each pulmonary nodule. The margin was then traced manually and our custom software delineated the approximate oval automatically. The maximum nodule perimeter difference was 26.5±23.3 mm for malignant and 16.6±16.9 mm for benign nodules, showing an almost statistically significant difference (P=.07). This study suggests that the maximum nodule perimeter difference to the approximate oval of the malignant nodules has a tendency to be longer than benign nodules.

Testicular seminoma presenting with mediastinal lymphadenopathy and gynecomastia

Chest computed tomography (CT) of a 22-year-old man with a history of long-term low fever and nonproductive cough demonstrated lymphadenopathy in the superior, middle, and posterior mediastinum. Slight bilateral gynecomastia was also observed on the CT scan. Subsequent physical examination and ultrasonography revealed a left testicular mass, and abdominal CT showed retroperitoneal lymphadenopathy. Left orchiectomy was performed, with the histological examination confirming the diagnosis of seminoma.

Can Peripheral Bronchopleural Fistula Demonstrated on Computed Tomography be Treated Conservatively? A Retrospective Analysis

Purpose Peripheral bronchopleural fistulas (BPF) are communications between a peripheral bronchus or the lung parenchyma and the pleural space. Although reported cases with peripheral BPF might have typical symptoms, we postulate that there may be BPF patients without typical symptoms who are diagnosed on computed tomography (CT) for the first time. Materials and Methods We searched retrospectively for how frequently BPF is found on CT in cases with known or suspected empyema or hydropneumothorax. Also, we examined the clinical charts to ascertain if a diagnosis of BPF was suspected in the CT reports or clinically, and to determine the outcome of each case. Results Thirteen thoracic cavities of 12 patients were included in this study. Of these, BPF was suspected clinically in only 1. Mention in the CT report about the presence of BPF was found in 2 cases. An apparent finding of BPF on CT was found in 7 of 13 (53%) thoracic cavities of 6 cases. The outcomes were that 1 patient died 1 month later due to multiple organ failure, and 1 patient was discharged subsequently after CT. In the other 10 cases, there was no exacerbation of the symptom regardless of definite evidence of BPF on CT. Conclusions In conclusion, when there is hydropneumothorax on CT, it is important for radiologists to diligently search for findings of peripheral BPF and to document it. However, a reference about the need for a surgical approach for BPF may not be required.