Comparison between quantitative computed tomography, scintigraphy, and anatomical methods for prediction of postoperative FEV1 and DLCO: effects of chronic obstructive pulmonary disease status and resected lobes.

BACKGROUND: Postoperative assessment of pulmonary function is important for estimating the risk of thoracic surgery and long-term disability following pulmonary resection, including predicted postoperative (ppo) forced expiratory volume (FEV) in one second (ppoFEV1) and percent predicted lung diffusion capacity for carbon monoxide (ppo%DLCO) estimation. The ppo values were compared using four different estimation methods between chronic obstructive pulmonary disease (COPD) and non-COPD patients and according to the resected lobe. METHODS: This prospective study included 59 eligible patients requiring single lobectomy and succeeded in performing pulmonary function tests at 3 and 12 months after lobectomy. The ppoFEV1 and ppo%DLCO were compared with poFEV1 and po%DLCO obtained at 3 and 12 months after lobectomy. The ppo values were estimated using the four usual methods: the 19-segment anatomical technique (S), perfusion scintigraphy (Q), quantitative CT (CT), and quantitative CT with low attenuation volume (CTLAV) subtraction. RESULTS: For non-COPD and COPD patients, the smallest mean difference between ppo and po values was observed by S for FEV1 and %DLCO. Based on the resected lobe, the smallest mean difference was observed by (I) Q for right upper lobectomy (RUL) excluding %DLCO at 12 months by S, (II) S for left upper lobectomy (LUL), (III) CT and CTLAV for right lower lobectomy (RLL), and (IV) CT and CTLAV for left lower lobectomy (LLL) at 12 months. The ppo values calculated by S for RUL (FEV1 at 3 and 12 months and %DLCO at 3 months) and by all four methods for LLL (FEV1 and %DLCO at 3 months) were smaller than the po values. CONCLUSIONS: The S method is adequate for calculating ppoFEV1 and ppo%DLCO when patients are classified as non-COPD and COPD. However, S sometimes overestimates the ppoFEV1 and ppo%DLCO when patients are classified according to the resected lobe. The CTLAV method may be the method of choice instead of S for calculating ppoFEV1 and ppo%DLCO in patients who undergo lung lobectomy despite the presence or absence of airflow limitation.

MONITORING DOSE-LENGTH PRODUCT IN COMPUTED TOMOGRAPHY OF THE CHEST CONSIDERING SEX AND BODY WEIGHT.

Dose-length product (DLP) is widely used as an indicator of the radiation dose in computed tomography. The aim of this study was to investigate the significance of sex and body weight in DLP-based monitoring of the radiation dose. Eight hundred computed tomographies of the chest performed using four different scanners were analysed. The DLP was compared with body weight by linear regression in men and women separately. The DLP was positively correlated with body weight, and dependence on sex and weight differed among scanners. Standard DLP values adjusted for sex and weight facilitated interscanner comparison of the radiation dose and its dependence on sex and weight. Adjusting the DLP for sex and weight allowed one to identify examinations with possibly excessive doses independently of weight. Monitoring the DLP in relation to sex and body weight appears to aid detailed comparison of the radiation dose among imaging protocols and scanners and daily observations to find unexpected variance.

[Usefulness of the FRFSE method in SPIO-MRI].

AIM: Super-paramagnetic iron oxide-enhanced magnetic resonance imaging (SPIO-MRI) is highly sensitive for liver tumors. This trial examined the optimal parameters of the fast recovery fast spin echo (FRFSE) method in SPIO-MRI. The FRFSE method is a pulse sequence with recovery of the compulsory longitudinal magnetization. The FRFSE method used in SPIO-MRI has better sensitivity for liver tumor, better tumor contrast, and can be used with respiratory gating. MATERIALS AND METHODS: The phantoms used included a ferucarbotran phantom, water phantom, and gelatin phantom. Each phantom was scanned by the FRFSE method and fast spin echo (FSE) method, with changing of scanning parameters, and each CNR was measured. Each CNR was given a point, and points were averaged according to each parameter. Parameters that obtained high average points were considered optimal parameters. RESULTS: The optimal parameters were set to TE=50 ms in the FRFSE method. The scan parameters optimized from the phantom study were used in a clinical case, and good results were achieved, as in the phantom study. CONCLUSION: We optimized the scan parameters of the FRFSE method and were able to suggest the usefulness of the FRFSE method in SPIO-MRI.

[Usefulness of lower extremity 2D TOF MR venography with respiratory compensation technique, and effect of patient positioning on the visualization of deep veins in the leg].

We evaluated the usefulness of two-dimensional time-of-flight (2D TOF) MR venography (MRV) of the lower extremity using the respiratory compensation (RC) technique. In addition, six variations in patient positioning of the leg and knee were investigated to determine the best method of visualizing the deep popliteal veins and lower leg. All data sets were reviewed and graded for visualization of the deep veins at the pelvis, thigh, and leg portion (4-point scale) by two radiologists and three radiological technologists. The same veins demonstrated with various positions of the patient were also evaluated in the same manner. In conclusion, 2D TOF MRV with RC resulted in increased uniformity of vein signal in the pelvic area. Furthermore, we should position the patient's leg so as not to compress the vein at the posterior portion of the leg, and not to over-extend the knee joint. This enabled the best results to be obtained in MRV of the lower extremity.