Percutaneous CT-guided fine-needle aspiration of pulmonary lesions: Results and complications in 409 patients.

The purpose of this study was to report our centre's experience in the results and complications of percutaneous CT-guided lung biopsy. A retrospective review of 409 patients who underwent percutaneous CT-guided fine-needle aspiration of suspicious lung lesions for more than 5 years was carried out. Nodule sizes ranged from 0.6 to 10 cm. The calibre of the needle used was 21-23 G. Specimen adequacy and patient outcome were evaluated. Each case was reviewed for complications. Sufficient diagnostic material was obtained in 369 (90%) of the 409 fine-needle aspirations. Diagnosis was malignancy in 290 (70%) samples, four (1%) samples were suspicious for malignancy, 65 (16%) samples were negative for malignancy and definite benign findings were identified in 10 (3%) specimens. There were 25 false-negative cases and one false-positive case. Sensitivity was 92% and specificity 98%. Pneumothorax was the most common complication and occurred in 17 (4%) patients. Only one of them required thoracic drainage. Blood effusion around the lesion or along the needle track was detected on the post-biopsy CT in 8 (2%) patients. However, only one of them suffered from a mild haemoptysis. Percutaneous CT-guided biopsy is an effective and fast procedure for diagnosis of suspected pulmonary malignancy, with a low complication rate.

Biexponential T2 relaxation time analysis of the brain: correlation with magnetization transfer ratio.

RATIONALE AND OBJECTIVES: To measure T2 relaxation times of normal white and gray matter using a novel CPMG sequence and investigate if any correlation exists between magnetization transfer ratio (MTR) and T2 relaxation-related parameters. MATERIALS AND METHODS: Seventeen normal volunteers participated on this study. A single-slice 32-echo sequence was used to calculate the T2 relaxation time of frontal and occipital white matter and cortical gray matter. T2 relaxation analysis included monoexponential and biexponential fitting whereas an F test was used to determine if biexponential fitting was statistically more accurate than monoexponential fitting. Short and long T2 constants were calculated as well as the signal fractions of each pool. MTR calculations were based on a three-dimensional gradient echo (3D FFE) proton density weighted sequence with and without an on-resonance composite prepulse. MTR and T2 relaxation times were calculated and linear regression analysis was applied. RESULTS: Biexponential fitting was more accurate comparing with monoexponential fitting in all WM and GM regions (F > 2.47, P < 0.01). Mean values of short T2 constant for frontal white matter (fWM), occipital white matter (oWM) and gray matter (GM) were 8.10, 9.36, and 22.23 milliseconds, respectively, whereas the mean values of long T2 constant were 85.1, 93.02, and 118.72 milliseconds, respectively. Mean restricted water percentages (RWP)-corresponding to the signal fraction of the protons with short T2-for the fWM, oWM, and GM were 22.01%, 23.36%, and 18.7%. Mean free water percentages (FWP)-corresponding to the signal fraction of the protons with long T2-for the fWM, oWM and GM were 77.99%, 76.64%, and 81.3%. Mean MTR values for fWM, oWM and GM were 68.4%, 68.2%, and 61.3%, respectively. No significant correlation was found in fWM and oWM between MTR and RWP, short and long T2 components while a moderate correlation existed in GM between MTR and RWP (r = 0.57; P = 0.02), MTR and short T2 component (r = -0.69; P = 0.004) and MTR and long T2 component (r = -0.62; P = 0.012). CONCLUSIONS: Two proton pools with different T2 decay characteristics can be separated in normal gray and white matter when using a multiecho sequence with short echo spacing. MTR and T2 relaxation times were significantly correlated in gray matter and the combination of both types of measurements may be helpful in studying myelin related disorders.