We present a method for measurement dynamic in vivo carpal motion patterns. The method consists of a 4-D rotational X-ray (RX) with improved image quality and image processing for accurate detection in vivo wrist motion measurements. Dynamic 3-D imaging yields a number of volume reconstructions of the wrist at different phases of its cyclic motion. Next, the carpal reconstructions are registered to their static acquired and segmented counterpart in all phases. With this information, the relation between the applied motion and carpal kinematic behavior is acquired, i.e., the motion patterns. We investigated the precision of the image acquisition and processing and tested it on three healthy subjects. The precision of the image acquisition and image processing is in the range of submillimeters and subdegrees, respectively, which is better than existing systems and sufficient for clinical investigations. Reproducibility measurements show some more deviation ($≫$1 $^{\circ}$). This method was tested on four human volunteers and agrees for the greater part with previously done invasive and nondynamic measurements. In vivo motion pattern measurement with 4-D-RX imaging and processing is accurate and noninvasive. The motion patterns can reveal disorders that could not have been detected in either video fluoroscopy, computed tomography, or MRI.
1 To determine the relative effects of nifedipine and nicardipine on left ventricular inotropy we directly injected into the left main coronary artery, in 12 patients with coronary artery disease, 20 min apart and in random order, 0.2 mg of each drug, which had previously been shown to increase coronary sinus blood flow equally. All variables were recorded at time (min), 1 through 5 and 7.5 and 10 min after injection. 2 Coronary sinus blood flow was increased by both drugs to the same extent (54% vs 56%). 3 Peak (+) and peak (–) dP/dt, and (dP/dt)/DP40 were affected by both drugs after 1 min, but by nifedipine to a significantly larger extent (P < 0.001, P < 0.001 and P < 0.005 respectively). 4 Left ventricular end-diastolic pressure was also increased by both drugs, but again was more pronounced after nifedipine (79% vs 30%, P < 0.001). 5 Left ventricular systolic pressure, mean aortic pressure and pulmonary artery pressure were not affected by nicardipine in contrast to nifedipine. 6 At doses that increased coronary sinus blood flow to a similar extent, nicardipine, in contrast to nifedipine, showed little effect on left ventricular inotropy.
Background: Lateral column lengthening (LCL) has become an accepted procedure for the operative treatment of the flexible flatfoot deformity. Hindfoot arthrodesis via a calcaneocuboid distraction arthrodesis (CCDA) has been considered a less favourable surgical option than the anterior open wedge calcaneal distraction osteotomy (ACDO), as CCDA has been associated with reduced hindfoot joint motion postoperatively. The ankle and subtalar joint ranges of motion were measured in patients who underwent an ACDO or CCDA procedure for flatfoot deformity. Methods: CT scanning was performed with the foot in extreme positions in five ACDO and five CCDA patients. A bone segmentation and registration technique for the tibia, talus and calcaneus was applied to the CT images. Finite helical axis (FHA) rotations representing the range of motion of the joints were calculated for the motion between opposite extreme foot positions of the tibia and the calcaneus relative to the talus. Results: The maximum mean FHA rotation of the ankle joint (for extreme dorsiflexion to extreme plantarflexion) after ACDO was 52.2 degrees ± 12.4 degrees and after CCDA 49.0 degrees ± 12.0 degrees. Subtalar joint maximum mean FHA rotation (for extreme eversion to extreme inversion) following ACDO was 22.8 degrees ± 8.6 degrees, and following CCDA 24.4 degrees ± 7.6 degrees. Conclusion: An accurate CT-based technique was used to assess the range of motion of the ankle and subtalar joints following two lateral column lengthening procedures for flatfoot deformity. Comparable results with a considerable amount of variance were found for the range of motion following the ACDO and CCDA procedures. Level of Evidence: III, Comparative Case Series
The effect of isoflurane 2.0 MAC on human atrioventricular conduction time was studied. A non-invasive recording system for the detection of His-Purkinje potentials based on signal averaging techniques was used. Recordings were made in 15 patients before and after induction with isoflurane. We were able to measure atrial (P-H) and His-Purkinje (HPS) conduction times in 11 patients. Mean (+/- SEM) P-H conduction time decreased from 101.8 +/- 5.3 to 89.3 +/- 3.3 ms (P less than 0.01). HPS conduction times did not change significantly. Heart rate increased significantly from 86.7 +/- 4.2 to 94.9 +/- 4.7 beats min-1 (P less than 0.05). Systolic blood pressure decreased from 117.3 +/- 4.6 to 94.1 +/- 4.7 mmHg (P less than 0.05). It is concluded that the effects of isoflurane on supraventricular conduction time in humans depend on interactions of several different mechanisms.
