To evaluate impaired respiratory mechanics in pulmonary emphysema, dynamic breathing magnetic resonance imaging (BMRI) was acquired with fast‐gradient echo pulse sequences at fixed thoracic planes over two to three slow, deep respiratory cycles in 6 controls and 28 patients with pulmonary emphysema including 9 patients undergoing lung volume reduction surgery (LVRS). Respiratory motions of the diaphragm and chest wall (D/CW) were assessed by a cineloop view, a fusion display of maximal inspiratory and expiratory images, and the time‐distance curves. By contrast with normal subjects with regular synchronous D/CW motions, the patients frequently showed reduced, irregular, or asynchronous motions, with significant decreases in the maximal amplitude of D/CW motions (MAD and MACW), and the length of apposition of the diaphragm (LAD) (P < 0.0001, P < 0.001, P < 0.01, respectively). After LVRS, nine patients showed improvements in D/CW configuration and mobility, with significantly increased MAD, MACW, and LAD (P < 0.01, P < 0.0001, and P < 0.05, respectively). In 40 studies of 28 patients including the post‐LVRS examinations, the normalized MAD and MACW significantly correlated with %FEV1 (r = 0.881 and r = 0.906; P < 0.0001, respectively). BMRI seems useful for noninvasively and directly assessing the impaired respiratory mechanics associated with abnormal ventilation in pulmonary emphysema, and also for monitoring the effects of LVRS. J. Magn. Reson. Imaging 1999;10:510–520. © 1999 Wiley‐Liss, Inc.

To evaluate impaired respiratory mechanics in pulmonary emphysema, dynamic breathing magnetic resonance imaging (BMRI) was acquired with fast-gradient echo pulse sequences at fixed thoracic planes over two to three slow, deep respiratory cycles in 6 controls and 28 patients with pulmonary emphysema including 9 patients undergoing lung volume reduction surgery (LVRS). Respiratory motions of the diaphragm and chest wall (D/CW) were assessed by a cineloop view, a fusion display of maximal inspiratory and expiratory images, and the time-distance curves. By contrast with normal subjects with regular synchronous D/CW motions, the patients frequently showed reduced, irregular, or asynchronous motions, with significant decreases in the maximal amplitude of D/CW motions (MAD and MACW), and the length of apposition of the diaphragm (LAD) (P F 0.0001, P F 0.001, P F 0.01, respectively). After LVRS, nine patients showed improvements in D/CW configuration and mobility, with significantly increased MAD, MACW, and LAD (P F 0.01, P F 0.0001, and P F 0.05, respectively). In 40 studies of 28 patients including the post-LVRS examinations, the normalized MAD and MACW significantly correlated with %FEV 1 (r ‫؍‬ 0.881 and r ‫؍‬ 0.906; P F 0.0001, respectively). BMRI seems useful for noninvasively and directly assessing the impaired respiratory mechanics associated with abnormal ventilation in pulmonary emphysema, and also for monitoring the effects of LVRS. J. Magn. Reson. Imaging 1999;10:510-520. 1999 Wiley-Liss, Inc. Index terms: lung; dynamic magnetic resonance (MR) imaging; pulmonary emphysemaAbbreviations: BMRI, breathing magnetic resonance imaging; D/CW, diaphragm and/or chest wall; MAD, maximal amplitude of respiratory motions of the diaphragm; MACW, maximal amplitude of respiratory motions of the chest wall; RM, respiratory muscle; LVRS, lung volume reduction surgery; PFT, pulmonary function test; SPECT, single-photon emission computed tomography; TDC, time-distance curve.

Purpose:To evaluate the influence of food intake on portal flow using unenhanced magnetic resonance imaging (MRI). Materials and Methods:The study population included 29 healthy subjects. A selective inversion recovery tagging pulse was used on the superior mesenteric vein (SMV) and splenic vein (SpV) to study the correlation of tagged blood in the portal vein (PV). MRI was performed before and 60 -90 min after a meal. Results:The flow signal from the SMV increased in 97% of the subjects after the meal. Before the meal the portal flow was dominated by flow from the SpV in 59% of the subjects, while it was dominated by flow from the SMV in 76% of the subjects after the meal. The most common distribution pattern of the flow signal from the SpV before the meal was in the central part of the main PV (55%), while it was in the left side (45%) after the meal. The most common distribution pattern of the flow signal from the SMV was in the bilateral sides of the main PV both before and after the meal (62%). Conclusion:This technique shows potential for evaluating pre-and postprandial alterations of flow from the SpV and SMV in the PV under physiological conditions. FOOD INTAKE CAN CHANGE the portal venous circulation compared to that in the fasting state. Some investigators have observed a significant increase in portal flow after food intake using echo-Doppler ultrasonography and other techniques. However, the mechanism behind these changes is still only partly understood (1-14). The portal vein (PV) is perfused mainly by flow from the superior mesenteric vein (SMV) and splenic vein (SpV). However, the effects of food intake on portal flow distribution from these veins are not well understood.The three-dimensional (3D) half-Fourier fast spinecho MRI technique can show the portal flow as high signal intensity without the use of contrast material. The use of a selective inversion-recovery tagging pulse in the blood is fundamentally an arterial spin labeling (ASL) approach (15,16). This approach has been used in clinical brain studies; however, it is not widely used for portal studies. When the 3D half-Fourier fast spin-echo MRI technique is combined with the selective inversionrecovery tagging pulse placed on the SpV or SMV, flow from each vein can be observed separately as tagged blood in the PV (17). As a result, the distribution and predominance of each flow into the PV, and the increase and decrease of each flow into the PV before and after food intake can be assessed noninvasively.The purpose of this study was to evaluate the influence of fasting and food intake on the intraportal venous flow distribution from the SpV and SMV by means of a single breath-hold 3D half-Fourier fast spin-echo MRI sequence with a selective inversion-recovery tagging pulse. MATERIALS AND METHODS Study PopulationTwenty-nine healthy individuals (17 men and 12 women, age range ϭ 21-55 years, mean ϭ 25 years) were studied. They had no history of endocrine, gastrointestinal, hepatic, or pancreatobiliary diseases. All of the volunteers gave ver...

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Gd-based aerosol can non-invasively image regional lung ventilation in spontaneously breathing animals, using an adequate aerosol delivery system. The combined use of Gd-DTPA perfusion MR imaging may be acceptable for defining regionally impaired lung function associated with acute airway obstruction and pulmonary arterial embolization.