Multimodality Non-rigid Image Registration for Planning, Targeting and Monitoring During CT-Guided Percutaneous Liver Tumor Cryoablation

Rationale and Objectives: To develop non-rigid image registration between pre-procedure contrast enhanced MR images and intra-procedure unenhanced CT images, to enhance tumor visualization and localization during CT-guided liver tumor cryoablation procedures. Materials and Methods: After IRB approval, a non-rigid registration (NRR) technique was evaluated with different pre-processing steps and algorithm parameters and compared to a standard rigid registration (RR) approach. The Dice Similarity Coefficient (DSC), Target Registration Error (TRE), 95% Hausdorff distance (HD) and total registration time (minutes) were compared using a two-sided Student’s t-test. The entire registration method was then applied during five CT-guided liver cryoablation cases with the intra-procedural CT data transmitted directly from the CT scanner, with both accuracy and registration time evaluated. Results: Selected optimal parameters for registration were section thickness of 5mm, cropping the field of view to 66% of its original size, manual segmentation of the liver, B-spline control grid of 5×5×5 and spatial sampling of 50,000 pixels. Mean 95% HD of 3.3mm (2.5x improvement compared to RR, p<0.05); mean DSC metric of 0.97 (13% increase); and mean TRE of 4.1mm (2.7x reduction) were measured. During the cryoablation procedure registration between the pre-procedure MR and the planning intra-procedure CT took a mean time of 10.6 minutes, the MR to targeting CT image took 4 minutes and MR to monitoring CT took 4.3 minutes. Mean registration accuracy was under 3.4mm. Conclusion: Non-rigid registration allowed improved visualization of the tumor during interventional planning, targeting and evaluation of tumor coverage by the ice ball. Future work is focused on reducing segmentation time to make the method more clinically acceptable

A comparison of the efficacy of heparinized and nonheparinized solutions for maintenance of perioperative radial arterial catheter patency and subsequent occlusion

In a randomized, double-blind, controlled study, we compared heparinized and nonheparinized infusions for the maintenance of perioperative arterial catheter patency and the incidence of subsequent radial arterial occlusion. Two-hundred patients were randomized into 2 groups to receive heparinized (group H, n = 100) or nonheparinized (group S, n = 100) flush solutions. Radial and ulnar blood flows were assessed using Doppler probe and pulse oximetry before, just after, and 24 h after decannulation by the same investigator. The cannulation site was examined for complications such as hematoma, nerve injury, and infection. The mean duration of cannulations was 378 +/- 159.0 min in group H and 332 +/- 154.6 min in group S. The mean number of corrective interventions caused by dampening of the pressure wave (mean number of positional changes [group S, 1.5 +/- 2.0; group H, 1.4 +/- 3.8] and mean number of manual flushes [group S, 1.3 +/- 1.7; group H, 1.2 +/- 1.2]) was not significantly different in both groups. After decannulation, partial or total occlusion developed in 20 group H patients and 16 group S patients (not significant). The incidence of occlusion was correlated to the presence of hematoma at the puncture site after decannulation (P = 0.013), long duration of cannulation (P = 0.04), and age < 65 yr (P = 0.009). In conclusion, there is no significant difference between heparinized and nonheparinized flush solutions for the maintenance of perioperative radial artery catheter patency

Radial nerve injury after general anaesthesia in the lateral decubitus position

A 43-year-old female patient underwent pyelolithotomy in the left lateral decubitus position. Her upper right arm was placed on a padded armboard. Surgery lasted for 240 min. Postoperatively, she complained of numbness of the dorsal part of her right hand and wrist drop. Neurological examination revealed hypoaesthesia of the dermatome of the right forearm and hand innervated by the radial nerve. Electromyography revealed advanced axonal degeneration of the radial nerve below the level of the elbow. Treatment with diclofenac, vitamin B and physiotherapy was started. Her symptoms improved gradually and at the 60th postoperative day, motor weakness had completely resolved. In order to prevent peri-operative nerve injury, careful positioning of every patient on the operating table with proper padding is essential, with attention paid to time-dependent risks. If an injury occurs, diagnosis and treatment should be started as rapidly as possible

Controlled hypotension and minimal inflation pressure: A new approach for pneumatic tourniquet application in upper limb surgery

Minimal inflation pressures are recommended for limb surgery to eliminate complications attributable to high inflation pressures with the pneumatic tourniquets. We applied controlled hypotension and a minimal inflation pressure (CHAMIP) technique to provide a bloodless surgical field. Thirty-six patients scheduled for upper extremity surgery were randomized equally to receive either normotensive anesthesia and conventional inflation pressures or controlled hypotension (systolic arterial blood pressure of 80-100 mm Hg and mean arterial blood pressure >60 mm Hg) and minimum inflation pressures. Anesthesia was induced with propofol IV bolus and remifentanil IV continuous infusion and maintained with propofol and remifentanil IV continuous infusion. To determine the minimal inflation pressure, the digital plethysmograph was applied to the second finger at the side of the operation and the tourniquet was inflated slowly until the arterial pulsations disappeared on the oscilloscope. A bloodless surgical field was obtained in almost all patients, even though systolic arterial blood pressures (100138 mm Hg versus 80-100 mm Hg) and applied tourniquet inflation pressures (270 nim Hg versus 110-140 mm Hg) were significantly lower in the hypotensive group. No complications associated with controlled hypotension were encountered. In conclusion, CHAMIP may be a safe and reliable method for upper extremity surgery performed with pneumatic tourniquets

Cutaneous anthrax of the hand: Some clinical observations

CONTEXT: Anthrax is a very rare disease in Europe and the United States. AIM: A case of cutaneous anthrax of the hand with a wide skin defect is presented and some clinical observations highlighted. CASE REPORT: A 56-year-old male patient with cutaneous anthrax attended our infectious diseases department with a swelling up to the upper arm. An urgent fasciotomy was undertaken with a diagnosis of compartment syndrome. A black eschar had formed on the dorsal surface of the hand. A superficial tangential escharectomy was performed. RESULTS: Viable fibrous tissue, about 4 to 5 mm in thickness over the extensor tendons, was found under the eschar. At the postoperative 2-year follow-up, remarkable healing was observed via skin grafting. CONCLUSIONS: Hand surgeons should be cautious against the compartment syndrome that may accompany cutaneous anthrax of the hand. A consistent viable fibrous tissue can be found below the eschar. The mechanism for the involvement of the hand dorsum needs further concern

Local connectivity and maps onto non-metrizable arcs

Three classes of locally connected continua which admit sufficiently many maps onto non-metric arcs are investigated. It is proved that all continua in those classes are continuous images of arcs and, therefore, have other quite nice properties

The effect of midazolam pre-medication on rocuronium-induced neuromuscular blockade

We investigated the effect of midazolam pre-medication on rocuronium-induced neuromuscular blockade during sevoflurane anaesthesia. Twenty-two patients scheduled for elective surgery were randomly divided to receive either no pre-medication (control group) or pre-medication with 0.1 mg/kg midazolam intramuscularly (midazolam group). Anaesthesia was induced with fentanyl and propofol, and maintained with sevoflurane and nitrous oxide in oxygen. Neuromuscular responses were monitored using acceleromyography. The onset and clinical duration of action, time to recovery of first twitch of train-of-four (TOF) response to 75% of control, recovery index and time for TOF recovery to 25% and 50% were recorded. Patient-related data were similar in both groups. The parameters recorded were not significantly different between the groups. Midazolam pre-medication does not influence the time-course of action of rocuronium during sevoflurane anaesthesia

The Soft Seal disposable laryngeal mask airway in adults: comparison of two insertion techniques without intra-oral manipulation

We investigated whether insertion of the disposable Soft Seal laryngeal mask airway (SSLM) was successful without intra-oral digital manipulation. One hundred patients undergoing anaesthesia using the SSLM were randomly assigned into two groups. Insertion was performed by either a direct or a rotational technique, both without intra-oral digital manipulation. The primary outcome measure was successful insertion at first attempt. Other outcomes included insertion time, fibreoptic assessment of the airway view and airway morbidity. The first attempt success rate was higher (98%) with the direct technique than with the rotational technique (75%; p = 0.002) but insertion time was faster with the latter method (mean [range] 15 [8-50] s) than with the direct method (20 [8-56] s; p = 0.035). Fibreoptic assessment and airway morbidity were similar in both groups. We conclude that the SSLM can be successfully inserted without intra-oral digital manipulation