Quantitative Computed Tomography Analysis of the Longitudinal Change Between Centrilobular and Paraseptal Emphysema Subtypes: A Retrospective Study.

OBJECTIVE: This study aimed to investigate the difference between the extent of centrilobular emphysema (CLE) and paraseptal emphysema (PSE) on follow-up chest CT scans and their relationship to the cross-sectional area (CSA) of small pulmonary vessels. METHODS: Sixty-two patients (36 CLE and 26 PSE) who underwent 2 chest CT scans were enrolled in this study. The percentage of low attenuation volume (%LAV) and total CSA of the small pulmonary vessels <5 mm 2 (%CSA < 5) were measured at the 2 time points. Analysis of the initial %CSA < 5 and the change in the %LAV and %CSA < 5 on follow-up imaging was performed. RESULTS: The initial %CSA < 5 was not significantly different between the CLE and the PSE groups (CLE, 0.66 vs. PSE, 0.71; P = 0.78). There was no significant difference in the longitudinal change in the %LAV between the 2 groups (CLE, -0.048% vs. PSE, 0.005%; P = 0.26). The longitudinal change in the %CSA < 5 in patients with PSE significantly decreased compared with those with CLE (CLE, 0.025% vs. PSE, -0.018%; P = 0.02). CONCLUSIONS: The longitudinal change in the %CSA < 5 was significantly different for patients with CLE and PSE, demonstrating an important pathophysiological difference between the subtypes.

A Long-term Persistent Vascular Fluorodeoxyglucose Uptake in a Patient with Large-vessel Vasculitis.

We herein report a case of large-vessel vasculitis in a 57-year-old woman who developed an intermittent fever and weight loss. While contrast-enhanced computed tomography was noncontributory, positron emission tomography-computed tomography (PET-CT) revealed the diffuse, intense uptake of fluorodeoxyglucose (FDG) in the aorta and its branches. Although she had no signs of relapse after successful oral corticosteroid therapy, PET-CT at 30 months revealed a persistent FDG uptake in the large vessels, which warranted regular follow-up imaging for vascular complications. In cases with an intense FDG uptake at the diagnosis, PET-CT follow-up after clinical remission may help predict the risk of relapse and vascular complications.

Endovascular retrieval of a Gunther-tulip vena cava filter migrated into the right atrium.

A 72-year-old male underwent placement of a Gunther-tulip vena cava filter to prevent development of a pulmonary embolism. One month later, when we tried to retrieve the Gunther-tulip vena cava filter via a transjugular approach, the filter detached from the snare and became free in the outer sheath. The Gunther-tulip vena cava filter did not reopen in the inferior vena cava probably because it became entangled with a thrombus; rather, the filter migrated into the right atrium. The filter orientation rendered the transjugular approach inappropriate; we used a bilateral transfemoral approach to aid filter retrieval. It is necessary to be very cautious when reopening a filter that has closed within the sheath. Although the filter migrated into the heart, we retrieved it using a combined approach.

Percutaneous transgastric pancreatic duct drainage for pancreaticojejunal leak after pancreaticoduodenectomy.

Pancreaticojejunal anastomotic leakage is one of the severe complications after pancreaticoduodenectomy and is often difficult to manage. A 64-year-old man status post pancreaticoduodenectomy had the gastroduodenal artery stump bleeding caused by the pancreaticojejunal anastomotic leakage, successfully treated by placing a covered stent. To control the leakage, subsequent percutaneous transgastric pancreatic duct puncture was performed under fluoroscopic guidance, targeting a surgically placed pancreaticojejunal internal drainage catheter. A 5 F catheter with side holes was inserted into the main pancreatic duct, the tip of which was placed in the anastomosed jejunum. The leak was successfully treated using this catheter. Percutaneous transgastric pancreatic duct drainage might be a useful and feasible option to resolve the condition.

Relationship between current smoking, visual CT findings and emphysema index in cigarette smokers.

PURPOSE: To evaluate whether visual CT findings could account for the effect of current smoking. METHODS: 500 CT scans were visually evaluated within each lobe. A multivariate model for emphysema index was constructed containing previously described confounders in addition to the visual components associated with smoking status. RESULTS: Current smokers displayed 23% less visual emphysema, 19% more airway wall thickening, and 188% more centrilogular nodule than former smokers (all p < 0.001). The effect of current smoking on the emphysema index decreased after adjustment with confounders and visual parameters. CONCLUSIONS: Visual CT findings could partially account for the effect of current smoking.

The Association Between Bronchial Wall CT Attenuation and Spirometry in Patients with Bronchial Asthma.

RATIONALE AND OBJECTIVE: The purpose of this study was to evaluate the correlation between generation-based bronchial wall attenuation on thin-section computed tomography (CT) scans and airflow limitation in patients with bronchial asthma. MATERIALS AND METHODS: This study included 28 bronchial asthma patients (13 men, 15 women; age range, 23-89 years) who underwent both chest CT and spirometry. On CT, the mean values of peak wall attenuation, wall area percentage, and luminal area were measured in the segmental, subsegmental, and sub-subsegmental bronchi of the right B1 and B10 bronchi. Correlations of the CT measurements with forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC), percent predicted forced expiratory flow at 25%-75% of the FVC (%pred forced expiratory flow25-75), and percent predicted peak flow rate were evaluated with Spearman's rank correlation test. RESULTS: The peak wall attenuation of each generation of segmental bronchi significantly correlated with the forced expiratory volume in 1 second/FVC (B1 segmental, ρ = -0.683, p < 0.0001; B1 subsegmental, ρ = -0.875, p < 0.0001; B1 sub-subsegmental, ρ = -0.926, p < 0.0001; B10 segmental, ρ = -0.811, p < 0.0001; B10 subsegmental, ρ = -0.903, p < 0.0001; B10 sub-subsegmental ρ = -0.950, p < 0.0001). Similar correlations were found between the peak wall attenuation and %pred forced expiratory flow 25-75 or percent predicted peak flow rate. Overall, the correlation coefficients were relatively high in the more peripheral bronchial generations. In all measurements, the coefficients of the peak wall attenuations were higher than those of the wall area percentage and luminal area. CONCLUSION: Peak attenuation of the bronchial wall, particularly in the peripheral bronchi, measured on CT is a good biomarker for the severity of bronchial asthma.

Early and Mid-Term Results of Endovascular Aortic Repair Using a Crossed-Limb Technique for Patients with Severely Splayed Iliac Angulation.

Objective: We evaluated early and mid-term results of endovascular aortic repair (EVAR) using crossed-limb and non-crossed-limb techniques. Material and Methods: From December 2011 to October 2013, 37 patients (31 men; mean age 75.4 years) were treated with EVAR (crossed-limb, 21 and non-crossed-limb, 16). We compared technical success, maximum short-axis diameter of abdominal aortic aneurysm, iliac angulation, time for catheterization of the short contralateral limb gate of the main body (SCT), and complications between the groups. Results: The mean follow-up period was 810±230 days. The technical success rate was 100%. There was no significant difference between the groups in terms of mean short-axis diameter. Iliac angulation was significantly wider in the crossed-limb group (53.3±14.6 vs. 39.4±13.0, p=0.0049). There was no significant difference between the groups in terms of SCT. Limb occlusion occurred in two cases (one crossed-limb and one non-crossed-limb). There were no aneurysm-related deaths. Conclusion: There were no differences between the crossed-limb and non-crossed-limb techniques in terms of early and mid-term results of EVAR. A crossed-limb technique can be performed safely without prolonged SCT even in severely splayed iliac angulation cases.

Selective venous sampling supports localization of adenoma in primary hyperparathyroidism.

BACKGROUND: Selective venous sampling (SVS) is an invasive localization study for persistent or recurrent hyperparathyroidism. PURPOSE: To assess the role of SVS in addition to non-invasive imaging for primary hyperparathyroidism (pHPT). MATERIAL AND METHODS: This study was approved by the institutional review board and included 14 patients who underwent SVS and subsequent parathyroidectomy between January 2014 and April 2017 following a clinical diagnosis of pHPT. All patients underwent pre-SVS non-invasive imaging, including ultrasound, computed tomography (CT), and 99mTc-MIBI scintigraphy, and sensitivity was assessed using the operative and pathological findings. RESULTS: In all but one case, a single parathyroid adenoma was responsible for the pHPT; the remaining case exhibited a chemical response following surgical removal of parathyroid tissue. The sensitivity (%) for ultrasound, CT, 99mTc-MIBI scintigraphy, and SVS was 76.9, 84.6, 69.2, and 76.9, respectively. SVS yielded positive results in four patients with discordant results and one patient with non-detectable results on imaging. In seven patients, a significant increase in the intact parathyroid hormone level was recognized only in the thyroid veins. The procedure time was in the range of 52-183 min (median = 89.5 min). CONCLUSION: The addition of SVS to a non-invasive imaging study would be helpful to locate the responsible lesion of pHPT with discordant or non-detectable results on imaging for initial surgical treatment as well.

Quantitative CT Evaluation of Small Pulmonary Vessels in Patients with Acute Pulmonary Embolism.

RATIONALE AND OBJECTIVES: The objective of this study was to investigate the correlation between the computed tomography (CT) cross-sectional area (CSA) of small pulmonary vessels and the CT obstruction index in patients with acute pulmonary embolism (PE) and the correlation between the changes in these measurements after anticoagulant therapy. MATERIALS AND METHODS: Fifty-two patients with acute PE were selected for this study. We measured the CSA less than 5 mm2 on coronal reconstructed images to obtain the percentage of the CSA (%CSA < 5). CT angiographic index was obtained based on the Qanadli method for the evaluation of the degree of pulmonary arterial obstruction. Spearman rank correlation analysis was used to evaluate the relationship between the initial and the follow-up values and changes in the %CSA < 5 and the CT obstruction index. RESULTS: There was no significant correlation between the %CSA < 5 and CT obstruction index on both initial (ρ = -0.03, P = 0.84) and follow-up (ρ = -0.03, P = 0.82) assessments. In contrast, there was a significant negative correlation between the changes in %CSA < 5 and the CT obstruction index (ρ = -0.59, P < 0.0001). CONCLUSIONS: Although the absolute %CSA < 5 and CT obstruction index were not significantly correlated, the changes in the values of the two parameters had a significant correlation. Changes in %CSA < 5, which can be obtained easily, can be used as biomarker of therapeutic response in patients with acute PE.

Percutaneous Direct Embolization for Pseudoaneurysm at the Gallbladder Fossa after Cholecystectomy.

Postoperative pseudoaneurysm at the gallbladder fossa is a rare complication of cholecystectomy. The typical clinical presentations of this condition are intraparenchymal or intraperitoneal hemorrhage or rupture into the gastrointestinal tract, and this may be life-threatening. For the treatment of pseudoaneurysms, percutaneous transarterial embolization is considered first-line. We present a case of pseudoaneurysm at the gallbladder following cholecystectomy, which was successfully treated with echo-guided percutaneous transhepatic direct embolization using N-butyl cyanoacrylate, after the failure of transarterial embolization.

Selective venous sampling for primary hyperparathyroidism: how to perform an examination and interpret the results with reference to thyroid vein anatomy.

Primary hyperparathyroidism (pHPT) causes hypercalcemia. The treatment for pHPT is surgical dissection of the hyperfunctioning parathyroid gland. Lower rates of hypocalcemia and recurrent laryngeal nerve injury imply that minimally invasive parathyroidectomy (MIP) is safer than bilateral neck resection. Current trends in MIP use can be inferred only by reference to preoperative localization studies. Noninvasive imaging studies (typically preoperative localization studies) show good detection rates of hyperfunctioning glands; however, there have also been cases of nonlocalization or discordant results. Selective venous sampling (SVS) is an invasive localization method for detecting elevated intact parathyroid hormone in the thyroid and/or internal jugular and brachiocephalic veins. SVS was developed mainly for postoperative patients with persistent or recurrent pHPT; however, SVS could also be useful before initial operations due to its high sensitivity to pHPT. Currently, SVS is generally indicated for recurrent HPT, and for cases with negative imaging study results for HPT or discordant results. Multi-detector row helical CT is useful for imaging the anatomy of the jugular and thyroid veins. Knowledge of the thyroid vein anatomy enables the creation of sampling points in the internal jugular and brachiocephalic veins for catheterization of the thyroid veins and venous anastomoses.

Idiopathic Pulmonary Fibrosis: Data-driven Textural Analysis of Extent of Fibrosis at Baseline and 15-Month Follow-up.

Purpose To evaluate associations between pulmonary function and both quantitative analysis and visual assessment of thin-section computed tomography (CT) images at baseline and at 15-month follow-up in subjects with idiopathic pulmonary fibrosis (IPF). Materials and Methods This retrospective analysis of preexisting anonymized data, collected prospectively between 2007 and 2013 in a HIPAA-compliant study, was exempt from additional institutional review board approval. The extent of lung fibrosis at baseline inspiratory chest CT in 280 subjects enrolled in the IPF Network was evaluated. Visual analysis was performed by using a semiquantitative scoring system. Computer-based quantitative analysis included CT histogram-based measurements and a data-driven textural analysis (DTA). Follow-up CT images in 72 of these subjects were also analyzed. Univariate comparisons were performed by using Spearman rank correlation. Multivariate and longitudinal analyses were performed by using a linear mixed model approach, in which models were compared by using asymptotic χ2 tests. Results At baseline, all CT-derived measures showed moderate significant correlation (P < .001) with pulmonary function. At follow-up CT, changes in DTA scores showed significant correlation with changes in both forced vital capacity percentage predicted (ρ = -0.41, P < .001) and diffusing capacity for carbon monoxide percentage predicted (ρ = -0.40, P < .001). Asymptotic χ2 tests showed that inclusion of DTA score significantly improved fit of both baseline and longitudinal linear mixed models in the prediction of pulmonary function (P < .001 for both). Conclusion When compared with semiquantitative visual assessment and CT histogram-based measurements, DTA score provides additional information that can be used to predict diminished function. Automatic quantification of lung fibrosis at CT yields an index of severity that correlates with visual assessment and functional change in subjects with IPF. © RSNA, 2017.

Decrease in Small Pulmonary Vessels on Chest Computed Tomography in Light Smokers Without COPD: An Early Change, but Correlated with Smoking Index.

PURPOSE: The aim of this study was to evaluate the relationship between the amount of smoking and the cross-sectional area (CSA) of small pulmonary vessels in light smokers without a diagnosis of chronic obstructive pulmonary disease (COPD). METHODS: This retrospective study was approved by our institutional review board, which waived the need for informed consent from patients. The study included 34 current smokers without COPD, who were defined as light smokers based on their smoking history (≤25 pack years). The CSA of small pulmonary vessels (<5 mm2 [CSA<5]) was measured on computed tomography (CT) scans, and the percentage of total CSA of the lung (%CSA<5) was calculated. The extent of emphysema was also assessed as the percentage of low attenuation area (%LAA, <-950 Hounsfield units). The correlations of %CSA<5 and %LAA with pack years were determined using the Spearman rank correlation. RESULTS: There was a significant negative correlation between %CSA<5 and pack years, whereas no significant correlation was found between %LAA and pack years. The correlations between pack years and percent predicted forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity were not significant. CONCLUSIONS: The percentage of total CSA of the lung made up of small pulmonary vessels in light smokers without COPD significantly decreases with increasing amount of smoking, in contrast to emphysema measurements. This suggests that small pulmonary vessels might have been injured or might have degenerated because of smoking, and might represent an initial stage in the development of COPD.

Texture-based Quantification of Centrilobular Emphysema and Centrilobular Nodularity in Longitudinal CT Scans of Current and Former Smokers.

RATIONALE AND OBJECTIVES: The effect of smoking cessation on centrilobular emphysema (CLE) and centrilobular nodularity (CN), two manifestations of smoking-related lung injury on computed tomography (CT) images, has not been clarified. The objective of this study is to leverage texture analysis to investigate differences in extent of CLE and CN between current and former smokers. MATERIALS AND METHODS: Chest CT scans from 350 current smokers, 401 former smokers, and 25 control subjects were obtained from the multicenter COPDGene Study, a Health Insurance Portability and Accountability Act-compliant study approved by the institutional review board of each participating clinical study center. Additionally, for 215 of these subjects, a follow-up CT scan was obtained approximately 5 years later. For each CT scan, 5000 circular regions of interest (ROIs) of 35-pixel diameter were randomly selected throughout the lungs. The patterns present in each ROI were summarized by 50 computer-extracted texture features. A logistic regression classifier was leveraged to classify each ROI as normal lung, CLE, or CN, and differences in the percentages of normal lung, CLE, and CN by study group were assessed. RESULTS: Former smokers had significantly more CLE (P <0.01) but less CN (P <0.001) than did current smokers, even after adjustment for important covariates such as patient age, GOLD stage, smoking history, forced expiratory volume in 1 second, gas trapping, and scanner model. Among patients with longitudinal CT scans, continued smoking led to a slight increase in CLE (P = 0.13), whereas sustained abstinence from smoking led to further reduction in CN (P <0.05). CONCLUSIONS: The proposed texture-based approach quantifies the extent of CN and CLE with high precision. Differences in smoking-related lung disease between longitudinal scans of current smokers and longitudinal scans of former smokers suggest that CN may be reversible on smoking cessation.

High-Flow Vascular Malformation in the Sigmoid Mesentery Successfully Treated with a Combination of Transarterial and Transvenous Embolization.

Mesenteric high-flow vascular malformation can cause various clinical symptoms and demand specific therapeutic interventions owing to its peculiar hemodynamics. We report a case of high-flow vascular malformation in the sigmoid mesentery which presented with ischemic colitis. The main trunk of the inferior mesenteric vein was occluded. After partially effective transarterial embolization, transvenous embolization was performed using a microballoon catheter advanced to the venous component of the lesion via the marginal vein. Complete occlusion of the lesion was achieved. Combination of transarterial and transvenous embolization may allow us to apply endovascular treatment to a wider variety of high-flow lesions in the area and possibly avoid the bowel resection.

Radiologic-pathologic discordance in biopsy-proven usual interstitial pneumonia.

The aim of this study was to compare the clinical, radiological and histological findings in a large population of subjects enrolled during a multicentre study of idiopathic pulmonary fibrosis, with a focus on discordance between imaging and histologic diagnoses of usual interstitial pneumonia (UIP).Two independent radiologists retrospectively reviewed 241 subjects who underwent high-resolution computed tomography (HRCT) and surgical lung biopsies. HRCT findings were classified as UIP, possible UIP and inconsistent with UIP. Histological findings were classified as definite, probable, possible and not UIP.Of the 241 cases, 102 (42.3%) had HRCT findings of UIP, 64 (26.6%) had possible UIP and 75 (31.1%) were inconsistent with UIP. Among those with UIP on HRCT, 99 (97.1%) had histologically definite or probable UIP (concordant group), and 71 (94.7%) of those with "inconsistent" HRCT features had histologically definite or probable UIP (discordant group). Discordant subjects were slightly younger and less likely to be smokers than concordant subjects, but no survival differences were identified.In this population of patients enrolled with a diagnosis of idiopathic pulmonary fibrosis, 94.7% of those with HRCT findings "inconsistent with UIP" demonstrated histological UIP. This suggests that the term "inconsistent with UIP" is misleading.

Proton Magnetic Resonance Imaging for Initial Assessment of Isolated Mycobacterium avium Complex Pneumonia.

RATIONALE: Computed tomographic (CT) radiography is the reference standard for imaging Mycobacterium avium complex (MAC) lung infection. Magnetic resonance imaging (MRI) has been shown to be comparable to CT for characterizing other pulmonary inflammatory conditions, but has not been rigorously tested for imaging MAC pneumonia. OBJECTIVES: To determine the feasibility of pulmonary MRI for imaging MAC pneumonia and to assess the degree of agreement between MRI and CT for assessing the anatomic features and lobar extent of MAC lung infections. METHODS: Twenty-five subjects with culture-confirmed MAC pneumonia and no identified coinfecting organisms were evaluated by thoracic MRI and then by chest CT imaging performed up to 1 week later. After deidentification, first the MRI and then the CT scans were scored 2 weeks apart by two chest radiologists working independently of one another. Discrepancies were resolved by a third chest radiologist. The scans were scored for bronchiectasis, consolidation or atelectasis, abscess or sacculation, nodules, and mucus plugging using a three-point lobar scale (absent, <50% of lobe, and >50% of lobe). Agreement analyses and ordinary least products regressions were performed. MEASUREMENTS AND MAIN RESULTS: A fixed bias was found between total CT and MRI scores, with CT scoring higher on average (median difference: 4 on a scale of 48; interquartile range: 3, 6). Fixed biases were found for bronchiectasis and consolidation or atelectasis subscale scores. Both fixed and proportional biases were found between CT and MRI mucus plugging scores. No bias was found between CT and MRI nodule scores. There was nearly perfect lobar percent agreement for more conspicuous findings such as consolidation or atelectasis and abscess or sacculation. CONCLUSIONS: In this exploratory study of 25 adult patients with culture-proven MAC lung infection, we found moderate agreement between MRI and CT for assessing the anatomic features and lobar extent of disease. Given the feasibility of chest MRI for this condition, future work is warranted to assess the clinical impact of MRI compared with CT in assessing progression of untreated MAC infection and response to treatment over time.

Quantitative CT measurements of small pulmonary vessels in chronic obstructive pulmonary disease: do they change on follow-up scans?

The aims of this study were to perform a longitudinal evaluation of the cross-sectional area (CSA) of small pulmonary vessels and the extent of emphysema measured on computed tomography (CT) scans of patients with chronic obstructive pulmonary disease (COPD), and to correlate the pulmonary vascular measurements with extent of emphysema. The institutional review board approved this retrospective study and waived the need for patients' informed consent. Seventy-four patients with COPD who underwent both initial and follow-up CT scans at an interval of ≥12 months were analysed. The CSA of small pulmonary vessels <5 mm(2) was measured, and the percentage of total CSA of the area of the lung (%CSA<5 ) was calculated. The extent of emphysema was assessed as the percentage of low attenuation area (%LAA, <-950 Hounsfield units). Comparisons between initial and follow-up measurements were performed using the Wilcoxon signed-rank test. The relationship between longitudinal changes in %CSA<5 and %LAA during the follow-up period was assessed using the Spearman rank correlation. The %LAA increased significantly on follow-up CT scans (P<0·0001). The %CSA<5 was slightly decreased on follow-up scans, but the difference was not significant. Although longitudinal change in %LAA was positively correlated with duration of follow-up period (ρ = 0·505, P<0·0001), longitudinal change in %CSA<5 was not. In conclusion, there was a progressive increase in the extent of emphysema over time, but no significant decrease in the CSA of small pulmonary vessels over the same time period.