The role of dynamic magnetic resonance imaging in the evaluation of pulmonary nodules and masses

The association of silicosis severity with pectoralis major muscle and subcutaneous fat volumes and the pulmonary artery/aorta ratio evaluated by CT

PURPOSE

Silicosis is an incurable occupational disease that sometimes rapidly progresses with fatal outcomes. We aimed to evaluate the association between disease severity and the change in the pectoralis major muscle volume (PMV), subcutaneous fat volume (SFV), and the pulmonary artery/aorta (P/Ao) ratio in patients with silicosis using computed tomography (CT).

METHODS

The study included 41 male silicosis patients and 41 control group subjects with available chest CT images. Using dedicated software, we measured PMV and SFV from the axial CT images. We calculated the P/Ao ratio and obtained body mass index (BMI) and forced expiratory volume/forced vital capacity (FEV1/FVC) results from hospital records. We used the chest X-ray profusion score according to the International Labor Organization (ILO) classification to evaluate the severity of the silicosis.

RESULTS

The mean age was 33.5±4.4 and 34.7±4.7 years in the silicotic and control groups, respectively. The mean BMI, PMV, SFV, and P/Ao values significantly differed between the study and control groups (P = 0.0009, P < 0.0001, P < 0.0001, and P = 0.0029, respectively). According to the ILO classification, there were 12 silicosis patients in category 1, 13 in category 2, and 16 in category 3. A significant difference was found between disease categories in terms of PMV, SFV, P/Ao, BMI, and FEV1/FVC values (P = 0.0425, P = 0.0341, P = 0.0002, P = 0.0492, and P = 0.0004, respectively).

CONCLUSION

Disease severity had a stronger association with decreased PMV and SFV and increased P/Ao ratios than BMI in patients with silicosis caused by denim sandblasting. Thus, CT evaluation might be a useful indicator of disease severity.

Thoracic Magnetic Resonance Imaging Applications in Children

Lung pathologies in the pediatric population can usually be detected using chest radiography. Multidetector computed tomography (MDCT) imaging is often used as a supplementary method in the evaluation of lung diseases. Recently, magnetic resonance imaging (MRI) techniques were found to be reliable in the evaluation of pulmonary diseases in the pediatric population. This review study describes the routine application of MRI examinations and the use of thoracic MRI with a particular focus in pediatric patients.

Lung cancer screening with MRI: characterization of nodules with different non-enhanced MRI sequences

BACKGROUND

There is increased interest in pulmonary magnetic resonance imaging (MRI) as a radiation-free alternative to computed tomography (CT) for lung cancer screening.

PURPOSE

To analyze MRI characteristics of pulmonary nodules with different non-enhanced sequences.

MATERIAL AND METHODS

Eighty-two participants of a lung cancer screening were included. MRI datasets of 32 individuals with 46 different nodules ≥ 6 mm were prospectively evaluated together with 50 controls by two readers. Acquired sequences were T2- short tau inversion recovery (STIR), T2, balanced steady-state free precession (bSSFP), 3D-T1, and diffusion-weighted imaging (DWI). Each sequence was randomly and separately viewed blinded to low-dose CT (LDCT). Size, shape, and contrast of nodules were evaluated on each sequence and then correlated with LDCT and histopathology.

RESULTS

All eight carcinomas were detected by T2-STIR, T2, and bSSFP, and 7/8 by 3D-T1. Contrast was significantly higher for malignant nodules on all sequences. The highest contrast ratio between malignant and benign nodules was provided by T2-STIR. Of eight carcinomas, seven showed restricted diffusion. Size measurement correlated significantly between MRI and LDCT. Sensitivity/specificity for nodules ≥ 6 mm was 85-89%/92-94% for T2-STIR, 80-87%/93-96% for T2, 65-70%/96-98% for bSSFP, and 63-67%/96-100% for 3D-T1. Seven of eight subsolid nodules were visible on T2-sequences with significantly lower lesion contrast compared to solid nodules. Two of eight subsolid nodules were detected by bSFFP, none by 3D-T1. All three calcified nodules were detected by 3D-T1, one by bSSFP, and none by T2-sequences.

CONCLUSION

Malignant as well as calcified and subsolid nodules seem to have distinctive characteristics on different MRI sequences. T2-imaging was most suitable for the detection of nodules ≥ 6 mm.

The Use of Breast Magnetic Resonance Imaging Parameters to Identify Possible Signaling Pathways of a Serum Biomarker, HE4

OBJECTIVES

This study aimed to investigate the relationship between breast magnetic resonance imaging (MRI) parameters; clinical features such as age, tumor diameter, N, T, and TNM stages; and serum human epididymis protein 4 (HE4) levels in patients with breast carcinoma and use this as a means of estimating possible signaling pathways of the biomarker, HE4.

METHODS

Thirty-seven patients with breast cancer were evaluated by breast MRI and serum HE4 levels before therapy. Correlations between parameters including age, tumor diameter T and N, dynamic curve type, enhancement ratio (ER), slope washin (S-WI), time to peak (TTP), slope washout (S-WO), and the serum level of HE4 were investigated statistically. Human epididymis protein 4 levels of early and advanced stage of disease were also compared statistically.

RESULTS

Breast MRI parameters showed correlation to serum HE4 levels and correlations were statistically significant. Of these MRI parameters, S-WI had higher correlation coefficient than the others. Human epididymis protein 4 levels were not statistically different in early and advanced stage of disease.

CONCLUSIONS

High correlation with MRI parameters related to neoangiogenesis may indicate signaling pathway of HE4.

Dual-energy computed tomography for evaluation of pulmonary nodules with emphasis on metastatic lesions

BACKGROUND

The contrast enhancement of pulmonary nodules is a differential diagnostic criterion which can be helpful in staging investigations.

PURPOSE

To investigate the impact of dual-energy computed tomography (DECT) with regards to the evaluation of pulmonary nodules with emphasis on metastatic lesions.

MATERIAL AND METHODS

DECT scans of the thorax were performed in 70 consecutive patients. Data of the lung were acquired in the arterial and in delayed venous phase. The virtual native and overlay image data based on arterial and delayed venous phase of these lesions were compared using CT density values (HU) within the nodule tested for statistical significance.

RESULTS

A total of 156 pulmonary lesions ≥5 mm were identified on 70 DECT scans. There were no significant differences between the CT-value measurements in the virtual native images based on the arterial and delayed venous phase (27.9+/-3.9 HU vs.28.1+/-4.2 HU, P = 0.89) and between the CT-value measurements in the overlay images based on the arterial und delayed venous phase (35.5+/-6.8 HU vs. 36.6+/-5.0 HU, P = 0.75). Metastases of colorectal carcinoma (51.4+/-9.4 HU vs. 32.5+/-8.9 HU, P = 0.0001), malignant melanoma (56.1+/-6.4 HU vs. 34.2+/-1.6 HU, P = 0.0045), and thyroid cancer (53.5+/-15.5 HU vs. 15.7+/-4.2 HU, P = 0.001) showed a distinct wash-out, whereas metastases of lung cancer (23.1+/-6.3 HU vs. 58.6+/-4.8 HU, P = 0.001), salivary gland cancer (41.4+/-20.3 HU vs. 65.7+/-15.7 HU, P = 0.023), and sarcoma (56.2+/-7.4 HU vs. 90.2+/-3.4 HU, P = 0.001) had an increased enhancement in the delayed venous phase.

CONCLUSION

The contrast enhancement behavior of pulmonary metastases can be evaluated with DECT and depends on the type of the primary malignant tumor.

Added value of DCE-MRI in the management of cystic-cavitary lung lesions

BACKGROUND AND OBJECTIVE

We evaluated the added value of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) to CT in the evaluation of cystic-cavitary lung lesions. We aimed to compare morphological parameters, including wall thickness and inner wall irregularity, and to determine whether DCE-MRI with morphological and dynamic parameters was useful in indeterminate lesions. We also aimed to investigate the added value of DCE-MRI in terms of whether to biopsy, and if so the site of biopsy.

METHODS

This prospective study included 39 consecutive patients with cystic and/or cavitary lung lesions detected by CT who then underwent additional DCE-MRI. After initial evaluation, the lesions were classified as benign, indeterminate or malignant and the findings of CT and DCE-MRI compared with each other by considering the final diagnosis that was determined by histopathological findings and clinical evaluation and follow up.

RESULTS

The mean values for wall thickness obtained by DCE-MRI were lower and the range of wall thickness for indeterminate lesions was narrower than those obtained by CT (5.50-11.50 mm and 5.75-13.50 mm for DCE-MRI and CT), and inner wall irregularity on DCE-MRI was more sensitive in malignant lesions. Also, DCE-MRI obviated biopsy in three benign patients and changed the biopsy site in two patients.

CONCLUSION

Our study suggests that DCE-MRI is helpful in indeterminate cystic-cavitary lung lesions, with morphological and dynamic features. It narrowed the range of wall thickness used for indeterminate lesions, was more sensitive than CT in determining malignant inner wall irregularity, and was also useful in determining the need for and appropriate site of biopsy. See article, page 576.

Correlation of diffusion MRI with the Ki-67 index in non-small cell lung cancer

BACKGROUND

The primary objective of the study was to evaluate the association between the minimum apparent diffusion coefficient (ADCmin) and Ki-67, an index for cellular proliferation, in non-small cell lung cancers. Also, we aimed to assess whether ADCmin values differ between tumour subtypes and tissue sampling method.

METHODS

The patients who had diffusion weighted magnetic resonance imaging (DW-MRI) were enrolled retrospectively. The correlation between ADCmin and the Ki-67 index was evaluated.

RESULTS

Ninety three patients, with a mean age 65 ± 11 years, with histopathologically proven adenocarcinoma and squamous cell carcinoma of the lungs and had technically successful DW-MRI were included in the study. The numbers of tumour subtypes were 47 for adenocarcinoma and 46 for squamous cell carcinoma. There was a good negative correlation between ADCmin values and the Ki-67 proliferation index (r = -0.837, p < 0.001). The mean ADCmin value was higher and the mean Ki-67 index was lower in adenocarcinomas compared to squamous cell carcinoma (p < 0.0001). There was no statistical difference between tissue sampling methods.

CONCLUSIONS

Because ADCmin shows a good but negative correlation with Ki-67 index, it provides an opportunity to evaluate tumours and their aggressiveness and may be helpful in the differentiation of subtypes non-invasively.