Fractal Dimension Analysis of MDCT Images for Quantifying the Morphological Changes of the Pulmonary Artery Tree in Patients with Pulmonary Hypertension

Objective

The aim of this study was to use fractal dimension (FD) analysis on multidetector CT (MDCT) images for quantifying the morphological changes of the pulmonary artery tree in patients with pulmonary hypertension (PH).

Materials and Methods

Fourteen patients with PH and 17 patients without PH as controls were studied. All of the patients underwent contrast-enhanced helical CT and transthoracic echocardiography. The pulmonary artery trees were generated using post-processing software, and the FD and projected image area of the pulmonary artery trees were determined with ImageJ software in a personal computer. The FD, the projected image area and the pulmonary artery pressure (PAP) were statistically evaluated in the two groups.

Results

The FD, the projected image area and the PAP of the patients with PH were higher than those values of the patients without PH (p < 0.05, t-test). There was a high correlation of FD with the PAP (r = 0.82, p < 0.05, partial correlation analysis). There was a moderate correlation of FD with the projected image area (r = 0.49, p < 0.05, partial correlation analysis). There was a correlation of the PAP with the projected image area (r = 0.65, p < 0.05, Pearson correlation analysis).

Conclusion

The FD of the pulmonary arteries in the PH patients was significantly higher than that of the controls. There is a high correlation of FD with the PAP.     

Pulmonary hypertension due to left heart disease: diagnostic and prognostic value of CT in chronic systolic heart failure

Objectives

To evaluate the ability of chest computed tomography (CT) to predict pulmonary hypertension (PH) and outcome in chronic heart failure with reduced ejection fraction (HFrEF).

Methods

We reviewed 119 consecutive patients with HFrEF by CT, transthoracic echocardiography (TTE) and right heart catheterization (RHC). CT-derived pulmonary artery (PA) diameter and PA to ascending aorta diameter ratio (PA:A ratio), left atrial, right atrial, right ventricular (RV) and left ventricular volumes were correlated with RHC mean pulmonary arterial pressure (mPAP) . Diagnostic accuracy to predict PH and ability to predict primary composite endpoint of all-cause mortality and HF events were evaluated.

Results

RV volume was significantly higher in 81 patients with PH compared to 38 patients without PH (133 ml/m² vs. 79 ml/m², p < 0.001) and was moderately correlated with mPAP (r=0.55, p < 0.001). Also, RV volume had higher ability to predict PH (area under the curve: 0.88) than PA diameter (0.79), PA:A ratio (0.76) by CT and tricuspid regurgitation gradient (0.83) and RV basal diameter by TTE (0.84, all p < 0.001). During the follow-up period (median: 3.4 years), 51 patients (43%) had HF events or died. After correction for important clinical, TTE and RHC parameters, RV volume (adjusted hazard ratio [HR]: 1.71, 95% CI 1.31–2.23, p < 0.001) and PA diameter (HR: 1.61, 95% CI 1.18–2.22, p = 0.003) were independent predictors of the primary endpoint.

Conclusion

In patients with HFrEF, measurement of RV volume and PA diameter on ungated CT are non-invasive markers of PH and may help to predict the patient outcome.

Key Points

? Right ventricular (RV) volume measured by chest CT has good ability to identify pulmonary hypertension (PH) in patients with chronic heart failure (HF) and reduced ejection fraction (HFrEF). ? The accuracy of pulmonary artery (PA) diameter and PA to ascending aorta diameter ratio (PA:A ratio) to predict PH was similar to previous studies, however, with lower cut-offs (28.1 mm and 0.92, respectively). ? Chest CT-derived PA diameter and RV volume independently predict all-cause mortality and HF events and improve outcome prediction in patients with advanced HFrEF.

     

Assessment of the Right Ventricular Function and Mass Using Cardiac Multi-Detector Computed Tomography in Patients with Chronic Obstructive Pulmonary Disease

Objective

We wanted to assess the relationship between measurements of the right ventricular (RV) function and mass, with using cardiac multi-detector computed tomography (MDCT) and the severity of chronic obstructive pulmonary disease (COPD) as determined by the pulmonary function test (PFT).

Materials and Methods

Measurements of PFT and cardiac MDCT were obtained in 33 COPD patients. Using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification, the patients were divided into three groups according to the severity of the disease: stage I (mild, n = 4), stage II (moderate, n = 15) and stage III (severe, n = 14). The RV function and the wall mass were obtained by cardiac MDCT. The results were compared among the groups using the Student-Newman-Keuls method. Pearson''s correlation was used to evaluate the relationship between the right ventricular ejection fraction (RVEF) and the wall mass results with the PFT results. P-values less than 0.05 were considered statistically significant.

Results

The RVEF and mass were 47±3% and 41±2 g in stage I, 46±6% and 46±5 g in stage II, and 35±5% and 55±6 g in stage III, respectively. The RVEF was significantly lower in stage III than in stage I and II (p < 0.01). The RV mass was significantly different among the three stages, according to the disease severity of COPD (p < 0.05). The correlation was excellent between the MDCT results and forced expiratory volume in 1 sec (r = 0.797 for RVEF and r = -0.769 for RV mass) and forced expiratory volume in 1 sec to the forced vital capacity (r = 0.745 for RVEF and r = -0.718 for RV mass).

Conclusion

Our study shows that the mean RV wall mass as measured by cardiac MDCT correlates well with the COPD disease severity as determined by PFT.     

Patients with severe emphysema have a low risk of radiation pneumonitis following stereotactic body radiotherapy

Objective:

To evaluate the risk of radiation pneumonitis (RP) after stereotactic radiotherapy (SBRT) for patients presenting with severe pulmonary emphysema.

Methods:

This study included 40 patients with Stage I non-small-cell lung cancer who underwent SBRT, 75 Gy given in 30 fractions, at the Tokyo Medical University, Tokyo, Japan, between February 2010 and February 2013. The median age of the patients was 79 years (range, 49–90 years), and the male:female ratio was 24:16. There were 20 T1 and 20 T2 tumours. 17 patients had emphysema, 6 had slight interstitial changes on CT images and the remaining 17 had no underlying lung disease. The level of emphysema was classified into three groups according to the modified Goddard''s criteria (severe: three patients, moderate: eight patients and mild: six patients). Changes in the irradiated lung following SBRT were evaluated by CT.

Results:

On CT images, RP was detected in 34 (85%) patients, and not in 6 (15%) patients, during a median observation period of 313 days. Of the six patients, three had severe emphysema and three had no underlying lung disease. Patients with severe emphysema had lower risk of RP than those with moderate emphysema (p = 0.01), mild emphysema (p = 0.04) and no underlying lung disease (p = 0.01).

Conclusion:

Patients with severe emphysema had a low risk of RP following SBRT.

Advances in knowledge:

Little is known about the association between RP and pulmonary emphysema. Patients with severe emphysema had lower risk of RP than those with no underlying lung disease.In addition to smoking, lung cancer has various causes, including emphysema and chronic obstructive pulmonary disease (COPD), which are common with underlying lung diseases.^1,2 Thus, patients with underlying lung diseases have a high possibility of having cancer.¹ Stereotactic body radiotherapy (SBRT) for Stage I non-small-cell lung cancer (NSCLC) has an excellent overall survival rate and local control; therefore, SBRT is widely considered a cure with fewer treatment-related toxicities.³ Accordingly, an increasing number of patients with co-morbidities, especially underlying lung diseases, are undergoing SBRT.Radiation pneumonitis (RP) is the most severe adverse event of SBRT. Some potential predictors for the risk factors of RP are reported;⁴ however, little is known about the association between RP and underlying lung diseases, such as pulmonary emphysema. Thus, we evaluated the relation between RP and pulmonary emphysema following SBRT in patients with Stage I NSCLC.     

Assessment of correlation between CT angiographic clot load score, pulmonary perfusion defect score and global right ventricular function with dual-source CT for acute pulmonary embolism

Objective

The purpose of this study was to prospectively investigate the correlation between CT angiographic clot load (CTACL) score, pulmonary perfusion defect (PPD) score and the global right ventricular function in the assessment of pulmonary embolism (PE) severity.

Methods

49 patients with acute PE, who underwent dual-source CT scan, were included in the study. CT angiography and perfusion imaging were performed. Data from electrocardiogram-gated coronary angiography scanning protocol were used for right ventricular function analysis. Two readers evaluated the CTACL and PPD scores using the Qanadli and Chae methods, respectively.

Results

The PPD score had a strong positive correlation with the CTACL score (r = 0.72, p<0.001) and both scores in turn had a strong positive correlation with the right ventricular/left ventricular (RV/LV) diameter ratio (r = 0.60, r = 0.62, p<0.001). However, the PPD score had a strong negative correlation with ejection fraction (EF) (r = −0.63, p<0.001) while the CTACL score had a low negative correlation with EF (r = −0.33, p = 0.02). Between the RV/LV<1 group (n = 35) and the RV/LV >1 group (n = 14), the PPD score, CTACL score, pulmonary artery trunk diameter, EF and reflux of inferior vena cava were significantly different, all with p<0.001. The end-systolic volume (p = 0.01) was significantly different but the end-diastolic volume (p = 0.11) and stroke volume (p = 0.08) showed no statistically significant difference between the two groups.

Conclusion

Therefore, considering PPD scores, CTACL scores and cardiovascular manifestations together may be helpful in the evaluation of PE severity.Pulmonary CT angiography (CTA) has been established as the first-line imaging technique for the diagnosis of pulmonary embolism (PE) in daily clinical practice [1,2]. Routine CT pulmonary angiography not only provides pulmonary arterial clot load information, but may even help to diagnose alternative causes for the patient''s symptoms, such as pneumothorax, pneumonia, pulmonary oedema or pleural effusion. However, it only provides anatomical and morphological images and no information regarding perfusion function. In acute PE patients, anatomical obstruction is the most important cause of compromised physiology, and the release of vasoactive and bronchoactive agents from platelets may lead to deleterious ventilation–perfusion mismatch [3]. Therefore, assessment of both anatomical obstruction and functional perfusion is important. The emergence of dual-source CT means that simultaneous evaluation of lung parenchyma perfusion and vascular blockage is now feasible. It has been shown to be a reliable method, with only one CT scan, in animal experiments [4] and clinical practice [5-7]. Besides lung parenchyma perfusion and arterial obstruction, right ventricular function is also an important tool for assessment of severity and is a predictor of mortality [8,9] in acute PE patients. Several studies [10-13] have shown that the global right ventricular function can be accurately assessed with electrocardiogram (ECG)-gated multislice CT. Recently, Chae et al [14] evaluated the pulmonary perfusion defect (PPD) score in acute PE and compared it with the CT angiographic obstruction score and right ventricular/left ventricular (RV/LV) diameter ratio obtained from dual-source CT. They evaluated the RV function from the ratio of RV/LV diameter only, without mentioning the global RV function parameters, such as end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF).The aim of this study is to investigate the correlation between CT angiographic clot load (CTACL), PPD score and the global RV function with dual-source CT in acute PE. These parameters can be used for the assessment of the severity of PE. We analysed the correlation between the PPD score and CTACL score withthe global RV function parameters, SV and EF. At the same time, we also assessed the correlation between the global right ventricular function and the cardiovascular parameters, which include the diameter of the pulmonary artery trunk (PAT), the short axis diameter ratio of RV/LV at four-chamber view and the reflux of contrast medium into the inferior vena cava (IVC).     

Hepatopulmonary Syndrome Induced by Common Bile Duct Ligation in a Rabbit Model: Correlation between Pulmonary Vascular Dilatation on Thin-Section CT and Angiography and Serum Nitrite Concentration or Endothelial Nitric Oxide Synthase (eNOS)1 Expression

Objective

To investigate the correlation between radiologic vascular dilatation and serum nitrite concentration and eNOS expression in the endothelial cell and pneumocyte in a rabbit model of hepatopulmonary syndrome induced by common bile duct ligation (CBDL).

Materials and Methods

Thin-section CT scans of the lung and pulmonary angiography were obtained 3 weeks after CBDL (n=6), or a sham operation (n=4), and intrapulmonary vasodilatation was assessed. The diameter and tortuosity of peripheral vessels in the right lower lobe by thin-section CT and angiography at the same level of the right lower lobe in all subjects were correlated to serum nitrite concentration and eNOS (endothelial nitric oxide synthase) expression as determined by immunostaining.

Results

The diameters of pulmonary vessels on thin-section CT were well correlated with nitrite concentrations in serum (r = 0.92, p < 0.001). Dilated pulmonary vessels were significantly correlated with an increased eNOS expression (r = 0.94, p < 0.0001), and the severity of pulmonary vessel tortuosity was found to be well correlated with serum nitrite concentration (r = 0.90, p < 0.001).

Conclusion

The peripheral pulmonary vasculature in hepatopulmonary syndrome induced by CBLD was dilated on thin-section CT and on angiographs. Our findings suggest that peripheral pulmonary vascular dilatations are correlated with serum nitrite concentrations and pulmonary eNOS expression.     

Non-invasive methods for estimating mPAP in COPD using cardiovascular magnetic resonance imaging

Purpose

Pulmonary hypertension (PH) is associated with a poor outcome in chronic obstructive pulmonary disease (COPD) and is diagnosed invasively. We aimed to assess the diagnostic accuracy and prognostic value of non-invasive cardiovascular magnetic resonance (CMR) models.

Methods

Patients with COPD and suspected PH, who underwent CMR and right heart catheter (RHC) were identified. Three candidate models were assessed: 1, CMR-RV model, based on right ventricular (RV) mass and interventricular septal angle; 2, CMR PA/RV includes RV mass, septal angle and pulmonary artery (PA) measurements; 3, the Alpha index, based on RV ejection fraction and PA size.

Results

Of 102 COPD patients, 87 had PH. The CMR-PA/RV model had the strongest diagnostic accuracy (sensitivity 92%, specificity 80%, positive predictive value 96% and negative predictive value 63%, AUC 0.93, p<0.0001). Splitting RHC-mPAP, CMR-RV and CMR-PA/RV models by 35mmHg gave a significant difference in survival, with log-rank chi-squared 5.03, 5.47 and 7.10. RV mass and PA relative area change were the independent predictors of mortality at multivariate Cox regression (p=0.002 and 0.030).

Conclusion

CMR provides diagnostic and prognostic information in PH-COPD. The CMR-PA/RV model is useful for diagnosis, the RV mass index and PA relative area change are useful to assess prognosis.

Key Points

? Pulmonary hypertension is a marker of poor outcome in COPD.? MRI can predict invasively measured mean pulmonary artery pressure.? Cardiac MRI allows for estimation of survival in COPD.? Cardiac MRI may be useful for follow up or future trials.? MRI is potentially useful to assess pulmonary hypertension in patients with COPD.

     

Pulmonary thin-section CT findings in acute Moraxella catarrhalis pulmonary infection

Objective

Moraxella catarrhalis is an important pathogen in the exacerbation of chronic obstructive pulmonary disease. The aim of this study was to assess the clinical and pulmonary thin-section CT findings in patients with acute M. catarrhalis pulmonary infection.

Methods

Thin-section CT scans obtained between January 2004 and March 2009 from 292 patients with acute M. catarrhalis pulmonary infection were retrospectively evaluated. Clinical and pulmonary CT findings in the patients were assessed. Patients with concurrent infection including Streptococcus pneumoniae (n = 72), Haemophilus influenzae (n = 61) or multiple pathogens were excluded from this study.

Results

The study group comprised 109 patients (66 male, 43 female; age range 28–102 years; mean age 74.9 years). Among the 109 patients, 34 had community-acquired and 75 had nosocomial infections. Underlying diseases included pulmonary emphysema (n = 74), cardiovascular disease (n = 44) or malignant disease (n = 41). Abnormal findings were seen on CT scans in all patients and included ground-glass opacity (n = 99), bronchial wall thickening (n = 85) and centrilobular nodules (n = 79). These abnormalities were predominantly seen in the peripheral lung parenchyma (n = 99). Pleural effusion was found in eight patients. No patients had mediastinal and/or hilar lymph node enlargement.

Conclusions

M. catarrhalis pulmonary infection was observed in elderly patients, often in combination with pulmonary emphysema. CT manifestations of infection were mainly ground-glass opacity, bronchial wall thickening and centilobular nodules.Moraxella catarrhalis is a Gram-negative, aerobic, oxidase-positive diplococcus that was first described in 1896 [1]. The pathogen, also known as Micrococcus catarrhalis, Neisseria catarrhalis and Brahamella catarrhalis, is a clinically important pathogen and is a common cause of respiratory infections, particularly otitis media in children and lower respiratory tract infection in elderly patients [2-5]. M. catarrhalis is considered to be the third most common and most important cause of bronchopulmonary infections after Streptococcus pneumoniae and Haemophilus influenzae [6,7]. In the Alexander project in Europe and the US between 1992 and 1993, M. catarrhalis was identified in 13.5% of bacterial isolates [8].M. catarrhalis has also gained attention as a nosocomial respiratory pathogen and as a community-acquired pathogen. On the basis of epidemiological evidence, the spread of M. catarrhalis was suggested to occur within the hospital environment [9,10]. McLeod et al [11] reported that 43 of 81 patients (53%) with M. catarrhalis infection were infected in a hospital and that the infection was associated with the proximity of the patient to other patients. Most nosocomial infections with M. catarrhalis involve the respiratory tract and outbreaks have been reported in respiratory units and paediatric intensive care units [10,12].M. catarrhalis infection has received increasing attention because it is an important factor in the acute exacerbation of chronic obstructive pulmonary disease (COPD). Acute exacerbation is a frequent event during the prolonged chronic course of COPD, which entails significant morbidity and mortality. The main aetiology for the majority of episodes is infection.Al-Anazi et al [13] reported a CT image of pneumonia associated with M. catarrhalis in a haematopoietic stem cell transplant patient. However, to the best of our knowledge, no other English-language studies of pulmonary CT findings in patients with acute M. catarrhalis pulmonary infection have been published. Therefore, this study aimed to assess the clinical and pulmonary thin-section CT findings in acute M. catarrhalis pulmonary infection.     

Visually stratified CT honeycombing as a survival predictor in combined pulmonary fibrosis and emphysema

Objective:

To determine whether visually stratified CT findings and pulmonary function variables are helpful in predicting mortality in patients with combined pulmonary fibrosis and emphysema (CPFE).

Methods:

We retrospectively identified 113 patients with CPFE who underwent high-resolution CT between January 2004 and December 2009. The extent of emphysema and fibrosis on CT was visually assessed using a 6- or 5-point scale, respectively. Univariate and multivariate Cox proportional regression analyses were performed to determine the prognostic value of visually stratified CT findings and pulmonary function variables in patients with CPFE. Differences in 5-year survival rates in patients with CPFE according to the extent of honeycombing were calculated using Kaplan–Meier analysis.

Results:

An increase in the extent of visually stratified honeycombing on CT [hazard ratio (HR), 1.95; p = 0.018; 95% confidence interval (CI), 1.12–3.39] and reduced diffusing capacity of lung for carbon monoxide (DLCO) (HR, 0.97; p = 0.017; 95% CI, 0.94–0.99) were independently associated with increased mortality. In patients with CPFE, the 5-year survival rate was 78.5% for <5% honeycombing, 55.7% for 5–25% honeycombing, 32% for 26–50% honeycombing and 33.3% for >50% honeycombing on CT.

Conclusion:

The >50% honeycombing on CT and reduced DLCO are important prognostic factors in CPFE.

Advances in knowledge:

Visual estimation of honeycombing extent on CT can help in the prediction of prognosis in CPFE.     

Multiphasic Perfusion CT in Acute Middle Cerebral Artery Ischemic Stroke: Prediction of Final Infarct Volume and Correlation with Clinical Outcome

Objective

To assess the utility of multiphasic perfusion CT in the prediction of final infarct volume, and the relationship between lesion volume revealed by CT imaging and clinical outcome in acute ischemic stroke patients who have not undergone thrombolytic therapy.

Materials and Methods

Thirty-five patients underwent multiphasic perfusion CT within six hours of stroke onset. After baseline unenhanced helical CT scanning, contrast-enhanced CT scans were obtained 20, 34, 48, and 62 secs after the injection of 90 mL contrast medium at a rate of 3 mL/sec. CT peak and total perfusion maps were obtained from serial CT images, and the initial lesion volumes revealed by CT were compared with final infarct volumes and clinical scores.

Results

Overall, the lesion volumes seen on CT peak perfusion maps correlated most strongly with final infarct volumes (R²=0.819, p<0.001, slope of regression line=1.016), but individual data showed that they were less than final infarct volume in 31.4% of patients. In those who showed early clinical improvement (n=6), final infarct volume tended to be overestimated by CT peak perfusion mapping and only on total perfusion maps was there significant correlation between lesion volume and final infarct volume (R²=0.854, p=0.008). The lesion volumes depicted by CT maps showed moderate correlation with baseline clinical scores and clinical outcomes (R=0.445-0.706, p≤0.007).

Conclusion

CT peak perfusion maps demonstrate strong correlation between lesion volume and final infarct volume, and accurately predict final infarct volume in about two-thirds of the 35 patients. The lesion volume seen on CT maps shows moderate correlation with clinical outcome.     

Liquid-Crystal Display Monitors and Cathode-Ray Tube Monitors: A Comparison of Observer Performance in the Detection of Small Solitary Pulmonary Nodules

Objective

To compare observer performance using liquid-crystal display (LCD) and cathode-ray tube (CRT) monitors in the interpretation of soft-copy chest radiographs for the detection of small solitary pulmonary nodules.

Materials and Methods

By reviewing our Medical Center''s radiologic information system, the eight radiologists participating in this study (three board-certified and five resident) retrospectively collected 40 chest radiographs showing a solitary noncalcified pulmonary nodule approximately 1 cm in diameter, and 40 normal chest radiographs. All were obtained using a storage-phosphor system, and CT scans of the same patients served as the gold standard for the presence of a pulmonary nodule. Digital images were displayed on both high-resolution LCD and CRT monitors. The readers were requested to rank each image using a five-point scale (1 = definitely negative, 3 = equivocal or indeterminate, 5 = definitely positive), and the data were interpreted using receiver operating characteristic (ROC) analysis.

Results

The mean area under the ROC curve was 0.8901±0.0259 for the LCD session, and 0.8716±0.0266 for the CRT session (p > 0.05). The reading time for the LCD session was not significantly different from that for the CRT session (37.12 and 41.46 minutes, respectively; p = 0.889).

Conclusion

For detecting small solitary pulmonary nodules, an LCD monitor and a CRT monitor are comparable.     

Quantitative H and hyperpolarized He magnetic resonance imaging: Comparison in chronic obstructive pulmonary disease and healthy never-smokers

Objective

The aim of this study was to quantitatively evaluate the relationship between short echo time pulmonary ¹H magnetic resonance imaging (MRI) signal intensity (SI) and ³He MRI apparent diffusion coefficients (ADC), high-resolution computed tomography (CT) measurements of emphysema, and pulmonary function measurements.

Materials and methods

Nine healthy never-smokers and 11 COPD subjects underwent same-day plethysmography, spirometry, short echo time ((TE) = 1.2 ms) ¹H and diffusion-weighted hyperpolarized ³He MRI (b = 1.6 s/cm²) at 3.0 T. In addition, for COPD subjects only, CT densitometry was also performed.

Results

Mean ¹H SI was significantly greater for never-smokers (12.1 ± 1.1 arbitrary units (AU)) compared to COPD subjects (10.9 ± 1.3 AU, p = 0.04). The ¹H SI AP-gradient was also significantly greater for never-smokers (0.40 AU/cm, R² = 0.94) compared to COPD subjects (0.29 AU/cm, R² = 0.968, p = 0.05). There was a significant correlation between ¹H SI and ³He ADC (r = −0.58, p = 0.008) and significant correlations between ¹H MR SI and CT measurements of emphysema (RA₉₅₀, r = −0.69, p = 0.02 and HU₁₅, r = 0.66, p = 0.03).

Conclusions

The significant and moderately strong relationship between ¹H SI and ³He ADC, as well as between ¹H SI and CT measurements of emphysema suggests that these imaging methods and measurements may be quantifying similar tissue changes in COPD and that pulmonary ¹H SI may be used to monitor emphysema as a complement to CT and noble gas MRI.     

Three-dimensional airway lumen volumetry: comparison with bronchial wall area and parenchymal densitometry in assessment of airway obstruction in pulmonary emphysema

Objectives

The purpose of this study was to compare three-dimensional airway lumen volumetry with bronchial wall area and parenchymal densitometry in the assessment of airway obstruction in pulmonary emphysema.

Methods

56 patients, who were smokers, underwent CT examination and pulmonary function tests (PFTs). For quantitative assessments, the following parameters were computationally calculated: (1) percentage of voxels −950, −960 and −970 HU in the lung (%LAA₋₉₅₀, %LAA₋₉₆₀ and %LAA₋₉₇₀, respectively); (2) percentage of partial bronchi luminal volumes per total luminal volumes (LV_main, main and distal bronchial volume/total luminal volume; LV_lobe, lobar and distal bronchial volume/total luminal volume); and (3) mean wall area percentages of segmental bronchi of the right apical and left apicoposterior segment (WA%_seg) and of subsegmental bronchi (WA%_sub) in the upper lobes. These parameters were correlated with PFTs and statistically compared between a chronic obstructive pulmonary disease (COPD) group [forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)<70] and a non-COPD group.

Results

FEV1, maximum mid-expiratory flow rate and forced expiratory flow at 25% vital capacity had significant correlation with LV_main (r>0.53, p<0.0001), LV_lobe (r>0.52, p<0.0001), WA%_seg (|r|>0.29, p<0.05) and WA%_sub (|r|>0.31, p<0.05). FEV1/FVC had significant correlation with all parameters (0.27<|r|<0.52, p<0.05). LV_main and LV_lobe and WA%_seg and WA%_sub were significantly different between the two groups (LV_main and LV_lobe; p<0.0001, WA%_seg and WA%_sub; p<0.05).

Conclusions

Bronchial luminal volumetric assessment better reflected the airflow limitation parameters.

Advances in knowledge

Bronchial luminal volumetric assessment can potentially be used to gauge airflow limitation in pulmonary emphysema.Worldwide, chronic obstructive pulmonary disease (COPD) is currently the fourth leading cause of mortality and the twelfth leading cause of disability, and by 2020 it is expected to be the third leading cause of death and the fifth leading cause of disability [1]. COPD is a slowly progressive disease characterised by airflow limitation, cough, sputum production and, at the later stages, dyspnoea. It is assessed using whole-lung pulmonary function tests (PFTs) and is characterised by increased airway obstruction and diffusional abnormalities detected in routine clinical practice. Recently, assessments of the extent and severity of pulmonary emphysema based on morphological findings in CT have become a popular method [2,3]. There are two main CT-based methods of assessing morphological change caused by COPD. One assesses destruction of lung parenchyma; the other assesses bronchial wall thickening and decreasing of the bronchial lumen.Destruction of lung parenchyma corresponds to the low attenuation areas (LAAs) detected through CT imagery. CT has been used to quantify emphysema by detecting LAAs and to assess disease severity quantitatively and qualitatively [4,5]. However, airflow limitation in COPD is a complicated phenomenon related only in part to emphysematous lung destruction; therefore, the extent of emphysema does not always correlate with the severity of airflow limitation [6,7]. On the other hand, regarding bronchial wall thickening and decreasing of the bronchial lumen, many investigators qualitatively and quantitatively evaluated the relationship between the CT findings and increased airflow limitation [8-10]. In CT-based quantitative analyses of these findings, the standard parameters are the area of the bronchial wall as a percentage and the ratio of the total bronchial cross-sectional area to the airway''s inner luminal area. In recent studies, airway dimensions have been obtained using volumetric CT, which allows for measurement in a plane orthogonal to the long axis of the airways [9,10]. However, evaluations of lung destruction are limited when two-dimensional (2D) measurements are made to only one or a few parts of the bronchi. This occurs because PFTs reflect the function of the whole [10]. Airflow obstruction can also be in different lobes or in different orders of bronchi, depending on the type and distribution of emphysema [10]. In addition, in patients with COPD, potential heterogeneity in the distribution of pathological bronchi has not yet been clarified [10].Current CT techniques with three-dimensional (3D) post-processing allow quantitative volumetry of various anatomical subsets, in addition to providing volumetric measurements. Quantitative volumetry could potentially add information different from that produced by conventional 2D measurement analysis. A recent report on volumetric analysis using a 3D technique to assess pulmonary hypertension showed a high correlation between pulmonary artery volumes and mean pulmonary artery pressures in patients with and without pulmonary hypertension [11]. In addition, quantitative volumetric assessment of the bronchial lumen in emphysema patients was shown to be potentially useful for clinical evaluations of disease severity [12]. However, to the best of our knowledge, no major studies have yet been reported comparing volumetric assessment of the bronchial lumen with 2D bronchial measurement analysis and LAAs for assessing the relationship between pulmonary function loss and quantitative CT parameters. We hypothesised that 3D airway lumen volumetry reflects airflow limitation in comparison with bronchial wall area and parenchymal densitometry in the assessment of airway obstruction. The purpose of this study was therefore to compare bronchial luminal volumetric assessment with other quantitative CT parameters to assess airflow limitation in pulmonary emphysema.     

Characterization of mandibular fractures using 64-slice multidetector CT

Objective

The aim of this study was to characterize mandibular fracture locations using 64-slice multidetector CT (MDCT).

Methods

CT scans of 138 patients with mandibular fractures who underwent 64-slice MDCT were studied. Mandibular fractures were classified into five types: median, paramedian, angle, condylar and coronoid process. Statistical analysis for the relationship between multiple fractures and type of mandibular fractures was performed using χ² test with Fisher''s exact test.

Results

The percentage of multiple mandibular fractures was 80.9% median type, 74.3% paramedian type, 52.9% angle type and 60.9% condylar type. The resultant data showed a significant relationship between multiple fractures and the median type (p = 0.000), paramedian type (p = 0.002) and condylar type (p = 0.003).

Conclusion

The results suggest that multiple fractures are related to the type of mandibular fractures.     

Assessment of Perfusion Pattern and Extent of Perfusion Defect on Dual-Energy CT Angiography: Correlations between the Causes of Pulmonary Hypertension and Vascular Parameters

Objective

To assess perfusion patterns on a dual-energy pulmonary CT angiography (DECTA) of pulmonary hypertension (PHT) with variable causes and to assess whether the extent of perfusion defect can be used in the severity assessment of PHT.

Materials and Methods

Between March 2007 and February 2011, DECTA scans of 62 consecutive patients (24 men, 38 women; mean age, 58.5 ± 17.3 [standard deviation] years; range, 19-87 years) with PHT were retrospectively included with following inclusion criteria; 1) absence of acute pulmonary thromboembolism, 2) maximal velocity of tricuspid regurgitation jet (TR Vmax) above 3 m/s on echocardiography performed within one week of the DECTA study. Perfusion patterns of iodine map were divided into normal (NL), diffuse heterogeneously decreased (DH), multifocal geographic and multiple peripheral wedging patterns. The extent of perfusion defects (PD), the diameter of main pulmonary artery (MPA) and the ratio of ascending aorta diameter/MPA (aortopulmonary ratio, APR) were measured. Pearson correlation analysis was performed between TR Vmax on echocardiography and CT imaging parameters.

Results

Common perfusion patterns of primary PHT were DH (n = 15) and NL (n = 12). The perfusion patterns of secondary PHT were variable. On the correlation analysis, in primary PHT, TR Vmax significantly correlated with PD, MPA and APR (r = 0.52, r = 0.40, r = -0.50, respectively, all p < 0.05). In secondary PHT, TR Vmax significantly correlated with PD and MPA (r = 0.38, r = 0.53, respectively, all p < 0.05).

Conclusion

Different perfusion patterns are observed on DECTA of PHT according to the causes. PD and MPA are significantly correlated with the TR Vmax.     

Attenuated right ventricular energetics evaluated using 11C-acetate PET in patients with pulmonary hypertension

Purpose

The right ventricle (RV) has a high capacity to adapt to pressure or volume overload before failing. However, the mechanisms of RV adaptation, in particular RV energetics, in patients with pulmonary hypertension (PH) are still not well understood. We aimed to evaluate RV energetics including RV oxidative metabolism, power and efficiency to adapt to increasing pressure overload in patients with PH using ¹¹C-acetate PET.

Methods

In this prospective study, 27 patients with WHO functional class II/III PH (mean pulmonary arterial pressure 39.8?±?13.5 mmHg) and 9 healthy individuals underwent ¹¹C-acetate PET. ¹¹C-acetate PET was used to simultaneously measure oxidative metabolism (k _mono) for the left ventricle (LV) and RV. LV and RV efficiency were also calculated.

Results

The RV ejection fraction in PH patients was lower than in controls (p?=?0.0054). There was no statistically significant difference in LV k _mono (p?=?0.09). In contrast, PH patients showed higher RV k _mono than did controls (0.050?±?0.009 min^?1 vs. 0.030?±?0.006 min^?1, p?<?0.0001). PH patients exhibited significantly increased RV power (p?<?0.001) and hence increased RV efficiency compared to controls (0.40?±?0.14 vs. 0.017?±?0.12 mmHg·mL·min/g, p?=?0.001).

Conclusion

The RV oxidative metabolic rate was increased in patients with PH. Patients with WHO functional class II/III PH also had increased RV power and efficiency. These findings may indicate a myocardial energetics adaptation response to increasing pulmonary arterial pressure.     

Capability of differentiating smokers with normal pulmonary function from COPD patients: a comparison of CT pulmonary volume analysis and MR perfusion imaging

Objective

To compare CT volume analysis with MR perfusion imaging in differentiating smokers with normal pulmonary function (controls) from COPD patients.

Methods

Sixty-two COPD patients and 17 controls were included. The total lung volume (TLV), total emphysema volume (TEV) and emphysema index (EI) were quantified by CT. MR perfusion evaluated positive enhancement integral (PEI), maximum slope of increase (MSI), maximum slope of decrease (MSD), signal enhancement ratio (SER) and signal intensity ratio (R_SI) of perfusion defects to normal lung.

Results

There were 19 class I, 17 class II, 14 class III and 12 class IV COPD patients. No differences were observed in TLV, TEV and EI between control and class I COPD. The control was different from class II, III and IV COPD in TEV and EI. The control was different from each class of COPD in R_SI, MSI, PEI and MSD. Differences were found in R_SI between class I and III, I and IV, and II and IV COPD. Amongst controls, MR detected perfusion defects more frequently than CT detected emphysema.

Conclusions

Compared with CT, MR perfusion imaging shows higher potential to distinguish controls from mild COPD and appears more sensitive in identifying abnormalities amongst smokers with normal pulmonary function (controls).

Key Points

? Detailed information is needed to diagnose chronic obstructive pulmonary disease. ? High-resolution CT provides detailed anatomical and quantitative information. ? Magnetic resonance imaging is demonstrating increasing potential in pulmonary function imaging. ? MR perfusion can distinguish mild COPD patients from controls. ? MRI appears more sensitive than CT in identifying early abnormalities amongst controls.     

Cystic Lung Disease: a Comparison of Cystic Size, as Seen on Expiratory and Inspiratory HRCT Scans

Objective

To determine the effects of respiration on the size of lung cysts by comparing inspiratory and expiratory high-resolution CT (HRCT) scans.

Materials and Methods

The authors evaluated the size of cystic lesions, as seen on paired inspiratory and expiratory HRCT scans, in 54 patients with Langerhans cell histiocytosis (n = 3), pulmonary lymphangiomyomatosis (n = 4), confluent centrilobular emphysema (n = 9), paraseptal emphysema and bullae (n = 16), cystic bronchiectasis (n = 13), and honeycombing (n = 9). Using paired inspiratory and expiratory HRCT scans obtained at the corresponding anatomic level, a total of 270 cystic lesions were selected simultaneously on the basis of five lesions per lung disease. Changes in lung cyst size observed during respiration were assessed by two radiologists. In a limited number of cases (n = 11), pathologic specimens were obtained by open lung biopsy or lobectomy.

Results

All cystic lesions in patients with Langerhans cell histiocytosis, lymphangiomyomatosis, cystic bronchiectasis, honeycombing, and confluent centrilobular emphysema became smaller on expiration, but in two cases of paraseptal emphysema and bullae there was no change.

Conclusion

In cases in which expiratory CT scans indicate that cysts have become smaller, cystic lesions may communicate with the airways. To determine whether, for cysts and cystic lesions, this connection does in fact exist, paired inspiratory and expiratory HRCT scans are necessary.     

Usual Interstitial Pneumonia and Non-Specific Interstitial Pneumonia: Serial Thin-Section CT Findings Correlated with Pulmonary Function

Objective

We wanted to demonstrate and compare the serial high-resolution CTs (HRCT) and the pulmonary function test (PFT) findings of the usual interstitial pneumonia (UIP) and the non-specific interstitial pneumonia (NSIP).

Materials and Methods

The serial HRCT scans and the PFT results were retrospectively analysed and compared for 35 patients having UIP without significant honeycombing (UIP-w/o hc, < 5% of honeycombing at CT), 35 patients having UIP with honeycombing (UIP-w/i hc, ≥ 5% of honeycombing), and 25 patients with NSIP. The mortality rates were also compared. Follow-up CT scans were available in 75 patients (29 UIP-w/o hc patients, 22 UIP-w/i hc patients and 24 NSIP patients) and the follow-up periods ranged from 150 to 2,370 days. The initial and follow-up PFT data were available for 71 patients.

Results

On the initial CT, significant differences were present between the UIP-w/i hc patients and both the UIP-w/o hc patients and the NSIP patients in the overall extent, ground-glass opacity (GGO) away from the reticulation, reticulation and honeycombing (all p < 0.05). Improvement was noticed in five (17%) of 29 UIP-w/o hc patients, none of 22 UIP-w/i hc patients, and 9 (37%) of 24 NSIP patients; deterioration was noted in six (21%) UIP-w/o hc patients, two (9%) UIP-w/i hc patients and three (13%) NSIP patients (p = 0.044 between UIP-w/o and UIP-w/i hc; p = 0.637 between UIP-w/o hc and NSIP; p = 0.007 between UIP-w/i hc and NSIP). The serial changes of the pulmonary function in the NSIP patients were different from those noted for the UIP-w/i hc and UIP-w/o hc patients (p = 0.440 between UIP-w/o and UIP-w/i hc; p = 0.022 between UIP-w/o hc and NSIP; p = 0.003 between UIP-w/i hc and NSIP). Five (14%) of the 35 patients with UIP-w/o hc, 16 (46%) of the 35 patients with UIP-w/i hc and three (12%) of the 25 patients with NSIP died (p = 0.002, comparison for the three groups).

Conclusion

On CT, NSIP and UIP-w/o hc patients have similar patterns of parenchymal abnormalities and a similar likelihood of change in the extent of disease on follow-up. Patients with UIP-w/i hc have distinctive features and a worst prognosis.     

Thrombus load and acute right ventricular failure in pulmonary embolism: correlation and demonstration of a “tipping point” on CT pulmonary angiography

Objectives

The aim of this study was to determine the correlation between increasing pulmonary embolism thrombus load and right ventricular (RV) dilatation as demonstrated by CT pulmonary angiography (CTPA) and to assess the thrombus load threshold which indicates impending RV decompensation.

Methods

2425 consecutive CTPAs were retrospectively analysed. Thrombus load using a modified Miller score (MMS), RV to left ventricular (RV:LV) ratio, presence of septal shift, and pulmonary artery and aorta size were analysed in 504 positive CTPA scans and a representative cohort of 100 negative scans. Results were correlated using non-parametric analysis (two-tailed t-test or χ² test) and Pearson’s rank correlation.

Results

Increasing thrombus load correlated with a higher RV:LV ratio, with a statistically significant difference in RV:LV ratios between the negative and positive pulmonary embolism (PE) cohorts. Larger thrombus loads (MMS ≥12 vs MMS <12) were strongly correlated with RV strain (mean RV:LV ratio, 1.323 vs 0.930; p<0.0001). Smaller thrombus loads had no significant influence on RV strain. Septal shift was also more likely with an MMS of ≥12, as was an increase in pulmonary artery diameter (r=0.221, p<0.001).

Conclusion

With increasing thrombus load in PE, there is CTPA evidence of RV decompensation with an MMS threshold of 12. This suggests a “tipping point” beyond which RV decompensation is more likely to occur. This is the first study to describe this tipping point between a thrombus load of MMS >12 and an increase in RV:LV ratio. This finding may help to improve risk stratification in patients with acute PE diagnosed by CTPA.Acute pulmonary embolism (PE) remains a diagnostic challenge for physicians and accounts for significant morbidity and mortality in hospitalised patients. In the United Kingdom, the incidence of proven PE is 60–70 per 100 000 in the population and mortality rates range from 6% to 15%. Clinical manifestations vary widely, from asymptomatic patients with small peripheral emboli to patients who present with circulatory collapse and large thromboembolic loads who may warrant thrombolysis. Between these extremes, there is a significant group presenting with PE who have apparent clinical haemodynamic stability but demonstrate radiological findings (e.g. via echocardiography or CT pulmonary angiography) or biomarkers [such as B-type natriuretic peptide (BNP) or troponin] of right heart strain, in whom the prognosis may be poorer and for whom the role of thrombolysis has not been established [1-4]. Studies to date have demonstrated that right heart strain is associated with higher mortality than no right heart strain [5,6], and CT assessment of right heart strain correlates with echocardiographic findings [7].CT pulmonary angiography (CTPA) has been established as the imaging modality of choice for the initial diagnosis of pulmonary thromboembolism [8,9], and is also used for assessing right ventricular (RV) afterload [10,11]. In addition, it enables quantification of thrombus load, for which a variety of scoring systems are available. These include the modified Miller score (MMS), a catheter pulmonary angiography score [12] adapted for CTPA by Bankier et al [13], and more complex systems such as the Qanadli and Mastora scores [14,15]. The aim of this study was to determine if there is a correlation between increasing thrombus load using MMS and RV dilatation as a predictor of RV failure according to CTPA findings.