Hidefumi Mimura

Risk factors for systemic air embolism as a complication of percutaneous CT-guided lung biopsy: multicenter case-control study.

PurposeTo determine risk factors for systemic air embolism by percutaneous computed tomography (CT)-guided lung biopsy.MethodsThis case-control study used data from 2216 percutaneous lung biopsy procedures performed over 11xa0years at 12 institutions in Japan. Systemic air embolism was identified by retrospective review of CT images obtained during and immediately after the procedures. To fulfill our objective, multiple variables were compared between cases and controls with univariate analyses by using Student’s t test and Fisher’s exact test for numerical and categorical values, respectively. Multivariate logistic regression analysis was then performed using selected variables.ResultsTen cases of systemic air embolism and 2,206 controls were identified. Univariate analyses showed that the lesions in the lower lobe (Pxa0=xa00.025) and occurrence of parenchymal hemorrhage (Pxa0=xa00.019) were significant risk factors. Multivariate analysis showed that the use of a larger biopsy needle was a significant risk factor (Pxa0=xa00.014).ConclusionParenchymal hemorrhage during the procedure, lesions in the lower lobe, and the use of larger biopsy needles may be risk factors for systemic air embolism by percutaneous CT-guided lung biopsy. Our findings may provide clues toward minimizing the risk of this complication.

Imaging of vascular tumors with an emphasis on ISSVA classification

The International Society for the Study of Vascular Anomalies (ISSVA) classification is becoming the international standard classification system for vascular tumors and vascular malformations. The ISSVA classification strictly distinguishes vascular tumors (neoplastic lesions) from vascular malformations (non-neoplastic lesions) based on whether there is a proliferation of vascular endothelial cells present, and it is an extremely useful classification system for determining therapeutic measures. For vascular tumors, it is clinically significant in terms of discriminating infantile hemangioma and rapidly involuting congenital hemangioma, which are expected to spontaneously regress, from other vascular tumors requiring treatment. Needless to say, clinical courses are important for diagnosis, and it is also important for radiologists to understand imaging findings on vascular tumors because such tumors have unique findings on diagnostic images. In this paper, vascular tumors are classified based on the ISSVA classification, and clinical and imaging findings are reviewed.

Phrenic nerve injury after radiofrequency ablation of lung tumors: retrospective evaluation of the incidence and risk factors.

PURPOSEnTo retrospectively investigate the incidence of and risk factors for phrenic nerve injury after radiofrequency (RF) ablation of lung tumors.nnnMATERIALS AND METHODSnThe study included 814 RF ablation procedures of lung tumors. To evaluate the development of phrenic nerve injury, chest radiographs obtained before and after the procedure were examined. Phrenic nerve injury was assumed to have developed if the diaphragmatic level was elevated after the procedure. To identify risk factors for phrenic nerve injury, multiple variables were compared between cases of phrenic nerve injury and randomly selected controls by using univariate analyses. Multivariate analysis was then performed to identify independent risk factors.nnnRESULTSnEvaluation of phrenic nerve injury from chest radiographs was possible after 786 procedures. Evidence of phrenic nerve injury developed after 10 cases (1.3%). Univariate analysis revealed that larger tumor size (≥ 20 mm; P = .014), proximity of the phrenic nerve to the tumor (< 10 mm; P < .001), the use of larger electrodes (array diameter or noninsulated tip length ≥ 3 cm; P = .001), and higher maximum power applied during ablation (≥ 100 W; P < .001) were significantly associated with the development of phrenic nerve injury. Multivariate analysis demonstrated that the proximity of the phrenic nerve to the tumor (< 10 mm; P < .001) was a significant independent risk factor.nnnCONCLUSIONSnThe incidence of phrenic nerve injury after RF ablation was 1.3%. The proximity of the phrenic nerve to the tumor was an independent risk factor for phrenic nerve injury.

Bronchiolitis obliterans organizing pneumonia after radiofrequency ablation of lung cancer: Report of three cases

The present report describes three cases of a bronchiolitis obliterans organizing pneumonia (BOOP)-like reactive pneumonitis following radiofrequency (RF) ablation for lung cancer. The incidence of BOOP-like reactive pneumonitis after RF ablation at the authors institution was estimated to be approximately 0.4% (three of 840 sessions). The patients presented with nonspecific symptoms. Computed tomography images showed consolidation or ground-glass opacity in a peripheral-dominant distribution and/or patchy air-space opacities. The disease was nonresponsive to antibiotic therapy but responded favorably to pulse therapy of steroids. BOOP-like reactive pneumonitis should be recognized as a complication following lung RF ablation.

Transcatheter Embolization of Pulmonary Artery False Aneurysm Associated with Primary Pulmonary Hypertension

AbstractA 29-year-old woman with primary pulmonarynhypertension presented with recurrent hemoptysis. Contrast-enhanced CTnof the chest demonstrated the enhanced mass surrounded by consolidationnrelated to parenchymal hemorrhage. Pulmonary angiography suggested thatnthe mass was a pulmonary artery false aneurysm. After a microcatheternwas superselectively inserted into the parent artery of the falsenaneurysm, the false aneurysm was successfully treated by transcatheternembolization with coils. Her hemoptysis has never recurred.

Association between reperfusion and shrinkage percentage of the aneurysmal sac after embolization of pulmonary arteriovenous malformation: evaluation based on contrast-enhanced thin-section CT images

PurposeTo investigate an association between reperfusion and the percentage of shrinkage of the aneurysmal sac after embolization of pulmonary arteriovenous malformation (PAVM) and to determine the cutoff value of the shrinkage percentage for indicating reperfusion.Materials and methodsTwenty-two PAVMs with completely embolized feeding arteries with coils were examined. The percentage of sac shrinkage and the presence of reperfusion were evaluated on computed tomography before and 1, 3, and 12xa0months after embolization. The percentages of sac shrinkage were compared between the occlusion and reperfusion groups. The receiver-operating characteristic (ROC) curve was generated to determine the diagnostic efficiency of reperfusion of PAVM by using shrinkage percentages.ResultsReperfusion was seen in 14, 13, and 11 lesions at 1, 3, and 12xa0months, respectively. The mean percentage of sac shrinkage was significantly different between the two groups at 3 and 12xa0months. The area under the ROC curve was 0.991 at 3xa0months and 0.934 at 12xa0months. All 9 lesions with <60xa0% sac shrinkage at 12xa0months showed reperfusion.ConclusionThe percentage of sac shrinkage was closely associated with reperfusion after embolization of PAVMs at 3 and 12xa0months. A shrinkage percentage of <60xa0% at 12xa0months indicated reperfusion.

Non-occlusive Mesenteric Ischemia after Splenic Metastasectomy for Small-Cell Lung Cancer

A 68-year-old man presented with severe abdominal pain. Seven months earlier, he had received systemic chemotherapy for small-cell lung cancer with solitary metastasis to the spleen, followed by splenectomy. Abdominal computed tomography and abdominal arterial angiography showed diffuse ischemia of the mesenteric artery without apparent occlusion. The patient also suffered from septicemia caused by Enterococcus faecium. Therefore, a diagnosis of non-occlusive mesenteric ischemia (NOMI) induced by septicemia was supposed. Although treatment with antibiotics and papaverine hydrochloride was administered and the necrotic tissue in the intestinal tract was resected, the patient died. Physicians should be aware that patients undergoing splenectomy are likely to be affected by septicemia, which may subsequently induce NOMI.

A case of autoimmune pulmonary alveolar proteinosis appearing as a localized ground-glass opacity

Pulmonary alveolar proteinosis (PAP) is a rare diffuse lung disease caused by abnormal intra-alveolar surfactant accumulation; it commonly appears as a “crazy-paving” pattern on high-resolution computed tomography. Here, we report a rare case of autoimmune PAP appearing as localized ground-glass opacity. An 82-year-old woman underwent chest computed tomography (CT) at another facility for cough, and a 2-cm localized ground-glass opacity was detected at the bottom of the right upper lung lobe. When she presented for follow-up at our hospital 6xa0months later, she was asymptomatic. The CT examinations performed at that point and 2xa0months thereafter did not reveal any changes. However, a CT examination performed after 5xa0months revealed slight increases in size and concentration. Adenocarcinoma in situ or minimally invasive adenocarcinoma was suspected. Incomplete lobulation between the upper and middle lobes of the right lung was detected, and video-assisted thoracoscopic lobectomy of the upper lobe and partial resection of the middle lobe of the right lung were performed. Histological examination revealed alveoli and terminal bronchioles filled with eosinophilic proteinaceous material positive for periodic acid–Schiff stain. The histopathological diagnosis was PAP and positive serum anti-GM-CSF antibody findings confirmed autoimmune PAP.