Raman-tailored photonic crystal fiber for telecom band photon-pair generation.

We report on the experimental characterization of a novel nonlinear liquid-filled hollow-core photonic crystal fiber for the generation of photon pairs at a telecommunication wavelength through spontaneous four-wave mixing (SFWM). We show that the optimization procedure in view of this application links the choice of the nonlinear liquid to the design parameters of the fiber, and we give an example of such an optimization at telecom wavelengths. Combining the modeling of the fiber and classical characterization techniques at these wavelengths, we identify for the chosen fiber and liquid combination SFWM phase-matching frequency ranges with no Raman scattering noise contamination. This is a first step toward obtaining a telecom band fibered photon-pair source with a high signal-to-noise ratio.

Intracoronary pressure measurement differences between anterior and posterior coronary territories.

INTRODUCTION: Intracoronary pressure measurements have improved assessment of angiographic intermediate coronary stenoses. Methodically, pressure equalization and actual measurements are frequently performed at different height levels, depending on the particular coronary territory analyzed. Considering a hypothetical influence of hydrostatic pressure and the supine position of the patient, differences in the results of intracoronary measurements between anterior and posterior vessels seem likely. The purpose of this study was to compare the results of intracoronary pressure measurements between anterior and posterior coronary territories. METHODS: Intracoronary pressure measurements of 214 coronary stenoses in 158 patients were analyzed. Fractional flow reserve (FFR) was measured in all stenosis and instantaneous wave-free ratio (iFR) in 197 stenoses in 144 patients. RESULTS: Both FFR (0.79 vs. 0.87, p < 0.001) and iFR values (0.86 vs. 0.94, p < 0.001) were significantly higher in posterior compared to anterior coronary vessels. Patients with only anterior or posterior lesions did not differ regarding clinical or lesion characteristics, in particular coronary stenosis severity (62.5 vs. 61.6 %, p = 0.27). CONCLUSIONS: Results of intracoronary measurements were systematically higher in the posterior coronary vessels when compared with anterior vessels. This phenomenon was independent of coronary stenosis severity or any clinical characteristics in our study population.

Computer-assisted scheduling of radiology resident call.

The difficulties inherent in assigning an entire residency group fair and equivalent daily call prompted the development of a computerized scheduling program at The University of Texas at Houston. Written in COBOL, the program is run on a CDC mainframe computer. Logic parameters restrict the number and frequency of calls per month, and each resident is coded for five available call types at two university hospitals. The foundation of the program's operation is an arbitrary point scale applied to each call type determined by its difficulty and time commitment. Residents' point totals each month are roughly balanced within a prescribed range, with call exchanges made by the computer if necessary. The computer-generated schedules are flexible and equitable, require little manual correction, and save time for the chief resident and the residency secretary.

An algorithmic approach to the roentgenographic evaluation of head trauma: medical and financial implications.

An algorithm was devised for the evaluation of patients with acute head trauma. The effectiveness of this strategy was tested with a retrospective chart review of 608 patients seen in a community hospital emergency room. The results of the algorithmic approach were compared to the original management of the patients. A financial savings of 65% was achieved and no significant intracranial pathology was missed using this approach.

Anterior subluxation of the cervical spine: hyperflexion sprain.

Anterior subluxation (hyperflexion sprain) is localized, purely ligamentous disruption of the cervical spine caused by a limited flexion force. When associated with a simple wedge fraction, also a flexion injury, anterior subluxation may be the more significant lesion. Radiographically, anterior subluxation is characterised by (1) a localized kyphotic angulation at the level of injury; (2) anterior rotation, or displacement, of the subluxed vertebra; (3) anterior narrowing and posterior widening of the disc space; (4) widening of the space between the subluxed vertebral body and the subjacent articular masses; (5) displacement of the inferior articulating facets of the subluxed vertebra with respect to their contiguous subjacent facets; and (6) widening of the interspinous space ("fanning"). The localized kyphotic angulation at the level of ligamentous disruption distinguishes pathologic anterior subluxation from diffuse "reversal of the normal cervical lordosis"; produced by voluntary positioning or muscle spasm. Anterior subluxation is clinically significant because of the approximate 20% incidence of delayed instability due to impaired ligamentous healing.

Intensifying screen for xeroradiography.

A high-atomic-number rare gas has been incorporated into xeroradiographic cassettes in order to increase the sensitivity of the process to x radiation. Preliminary results indicate that krypton gas at 1-atm pressure increases the sensitivity by approximately a factor of 2 in the mammography energy region.

Identifying risk factors for imminent death in cancer patients with acute dyspnea.

A substantial proportion of cancer patients presenting to an emergency center (EC) or clinic with acute dyspnea survives fewer than 2 weeks. If these patients could be identified at the time of admission, physicians and patients would have additional information on which to base decisions to continue therapy to extend life or to refocus treatment efforts on palliation and/or hospice care alone. The purpose of this study was to identify risk factors for imminent death (survival

Fundamentals course for 1st-year radiology residents.

RATIONALE AND OBJECTIVES: The authors set out to provide 1st-year residents with basic knowledge to make conferences more useful, to make their knowledge more uniform, and to assess their competency to begin night call. MATERIALS AND METHODS: Faculty taught three afternoon sessions a week in subspecialty areas of radiology, including physics, during the 1st 6 months of residency. Material selected was believed to be essential for the understanding of that subspecialty's didactic lecture series. Emphasis was also placed on diagnoses residents would be expected to make once they began taking night call. Material was presented through lectures, images, and unknown cases. An examination was administered at the end of the course. Residents were allowed to begin night call only after completing the course and passing the final examination. RESULTS: All 1st-year residents completed the course and passed the examination. Their scores ranged from 70% to 83.3%. CONCLUSION: Residents liked the course and reported feeling ready to begin call. Faculty reported the residents who completed the course were more knowledgeable prior to formal rotations than residents from previous years who had not taken the course.

Xerotomography of pulmonary lesions.

Xerography in combination with tomography is a useful modality in evaluating pulmonary lesions. Comparison is made between this technique and conventional film tomography. Xerotomography is felt to be preferable although it requires considerably higher radiation exposure to the patient.

Endometrial Nd-YAG laser ablation by hysterofibroscopy: long-term results of 137 cases.

OBJECTIVE: In our gynecology department, we have been performing endometrial laser ablation (ELA) under video control using a flexible hysteroscope since 1989. The aim of this study is to evaluate the long term results of our experience. STUDY DESIGN: We went back to the files of 137 patients treated between 1989 and 1993. These women (mean age 42 years) exhibited menorrhagia unamenable to medical treatments which had been developing for 28 months. Mean hysterometry was 9.8 cm. A hysteroscopy with ELA was performed. Our procedure lasts 19 min on average and uses 0.9 1 of glycocol. There were no perforations. Six patients presented a fever above 38 degrees C within the next 48 h; only one developed a true endometritis necessitating antibiotherapy. One patient who had received several GnRH agonist courses had a coagulation of the uterus and had to be hysterectomised. RESULTS: Nine patients were lost to follow-up; for the others, mean follow-up was 32 months. Seventeen women (13.3%) were hysterectomised, including the patient with a coagulation necrosis of the myometrium. In most cases, this was for undetected adenomyosis or fibromas evolving after hysteroscopy. Bleeding recurred in two other patients; they refused hysterectomy but should be counted as failures of this method. Among the 109 patients (85.1%) considered a success, 35 have had menopause since the procedure. CONCLUSION: ELA is a simple quick procedure which significantly reduces the number of hysterectomies. In addition, the economic value of ELA is beginning to be assessed in the literature. This long-term study should allow the indications to be better defined by eliminating patients with a high risk of failure and should lead to improved results.

Induction of labor in twin pregnancy after 36 weeks does not increase maternal-fetal morbidity.

OBJECTIVE: To compare maternal and perinatal outcomes in twin pregnancy patients without any fetal or maternal disease, managed by labor induction or expectant management after 36 weeks gestation. METHODS: We conducted a case-control study of 81 patients: labor induction (n=36) vs. expectant management (n=45). Labor was induced using oxytocin (n=18), vaginal prostaglandins (n=6) or intrauterine balloon catheter (n=12) according to the Bishop score. Maternal and perinatal outcome variables were compared among both groups. RESULTS: The characteristics of the labor induction group and the expectant management group were not statistically different, except for the rate of nulliparae (55.6% vs. 33.3%) and the rate of epidural analgesia (100% vs. 80%). There was no significant difference in labor time (6.5+/-2.8 h vs. 6.0+/-3.6 h), cesarean section rate (8.3% vs. 13.3%) or duration of maternal hospitalization (7.3+/-2.0 days vs. 7.5+/-2.3 days) in the labor induction group and in the expectant management group, respectively. The birth weight was higher in the labor induction group than in the expectant management group (2639+/-352 g vs. 2463+/-298 g, P<0.001). The rate of Apgar score <7 at 5 min was 0% and 3.3%, respectively. Neonatal intensive care unit admission occurred in 30.5% and 26.6% of the groups, respectively. No perinatal death was reported. CONCLUSION: Induction of labor may be proposed to patients with uneventful twin pregnancy after 36 weeks gestation without increasing maternal-fetal morbidity.

Management of septate uterus by flexible hysteroscopy and Nd:YAG laser.

OBJECTIVE: To evaluate the efficiency of flexible Nd-YAG laser hysteroscopic metroplasty. METHODS: We present a retrospective study of 17 patients treated for septate uteri between 1990 and 1995. The indication of hysteroscopy was recurrent abortion in nine cases and eight with primary infertility with indication of IVF in another five cases. We did not prescribe any pretreatment. A flexible hysteroscope with a 100-W Nd:YAG laser was used with glycine-controlled flow. The septum was divided by the laser after exploration of the cavity. We proposed a control office hysteroscopy 2 months after surgery to prevent uterine adhesions. RESULTS: There was no complication. Twelve patients conceived with 10 live births at term and two spontaneous abortions. Four are still infertile, two were lost from the study and two no longer desired pregnancy. Resectoscopic studies showed the same results. CONCLUSION: The advantages of this method are the excellent ergonomic properties of the fibroscope and the safety of the laser. We suggest that metroplasty does not improve the pregnancy rate but only the pregnancy outcome of these patients. However, for those with the indication of IVF the procedure seems useful in avoiding abortion.

Use of provisional prostheses with osseointegration.

The ingenuity that has characterized the fabrication of provisional prostheses has been readily adapted to the osseointegration technique. Implant abutments do not need protection during final prosthesis fabrication stages as teeth do. However, compelling arguments can be made in favor of esthetic, comfortable, and functional provisional prostheses supported by implants, even if they are worn for only a few weeks. The prosthodontic contribution to a patient's quality of life throughout all stages of treatment is thereby enhanced.

[Endometrial thermocoagulation via balloon: technique, mechanism of action, and evaluation]. / Thermocoagulation endométriale par ballonnet: technique, mécanisme d'action et évaluation.

Thermal balloon endometrial ablation is indicated for women suffering from menorrhagia. This easy technique can be performed safely, without using operative hysteroscopy. The rate of minor complications is low (< 4%). Thermotherapy treats the endometrium and superficial myometrium tissues without risk of injury to the bladder and bowels. The success rate of this operation is 90% in selected patients of studies published between 1996 and 1998, with a follow-up period of 12-24 months. However, long-term randomized controlled studies are needed to compare thermotherapy and other endometrial ablation procedures.

[BNP elevation due to a subdural hematoma - misled by a biomarker]. / BNP-Erhöhung bei subduralem Hämatom - durch einen Biomarker in die Irre geführt.

HISTORY AND ADMISSION FINDINGS: A 73-year-old man with a mechanical aortic valve and a history of congestive heart failure was admitted to our hospital with an unspecifically reduced general condition. Physical examination was normal according to age apart from mechanic valve closure tones and a 2/6 sytolic murmur at Erb's point. INVESTIGATIONS: Inflammation markers were elevated (leukocytosis 22 100/µl, CRP 22 mg/dl ), there was mild anemia (hemoglobin 9.7 mg/dl) and digitoxin blood level was increased to 56 µg/l (therapeutic range 10-30 µg/l). Because NT-proBNP was highly elevated, further diagnostics focused on cardiac causes of BNP elevation despite missing clinical symptoms. Transesophageal echocardiography was inconspicuous and blood cultures were negative. Therefore an infection of unknown origin or an emerging endocarditis were presumed. TREATMENT AND COURSE: Pragmatic treatment with antibiotics and diuretics as well as discontinuation of digitoxin led to normalization of leukocytes, CRP and digitoxin levels. But the patient's general condition deteriorated further, NT-proBNP rose to 37731 pg/ml and the patient became disoriented. On thorough questioning the patient's relatives stated that he had fallen 6 weeks previously. Computed tomography then revealed a large chronic subdural hematoma which had caused the NT-proBNP elevation. The patient was operated successful. CONCLUSION: In patients with elevated BNP and atypical symptoms neurological causes should be considered.

[Pulsatile tumor on the left side of the thorax after heart surgery]. / Pulsierender Tumor auf der linken Thoraxseite nach Herzoperation.

HISTORY AND ADMISSION FINDINGS: In a 67-year-old woman a large haematoma developed on the left side of the chest after two sternotomies because of an aortic valve and aorta ascendens replacement for aortic type A dissection. After a few weeks, a pulsating mass remained over the 6th left parasternal intercostal space. A consultant general surgeon punctured the lesion and aspirated bright red blood. The patient was transferred for further diagnostic procedures to the cardiology department. INVESTIGATIONS: Ultrasound examination of the pulsating mass showed a 35 mm echo-free cavity with turbulent flow in the color Doppler. To clarify the inflow into this perfused cavity magnetic resonance imaging (MRI) with angiography of the thorax vessels was performed. The cavity was found to be a perfused pseudoaneurysm originating from the native left mammary artery. The aneurysm had a 6 mm long neck and a diameter of 35 mm. An interventional closure was planned. TREATMENT AND COURSE: With access via the right groin a 6 French LIMA guiding catheter was inserted into the origin of the left internal mammary artery. With a 0.014 inch Balance Middleweight coronary guide wire it was possible to engage the pseudoaneurysm. Over the wire, a tracker 18 infusion catheter was pushed down and placed in the pseudoaneurysm. The closure was performed by insertion of a 0.018 inch 3 cm/4 mm Hilal Microcoil into the aneurysm neck. The mammary artery was anatomically and functionally unaffected. After the deposit of a coil, the inflow was stopped. An ultrasound showed a blood coagulation in the pseudoaneurysm, which decreased in size over time. CONCLUSION: After sternotomy a pseudoaneurysm of the left internal mammary artery had developed. As a noninvasive imaging modalitiy the magnetic resonance angiography showed well the exact flow into the aneurysm and allowed the planning of the intervention. The closure was achieved with a microcoil with preservation of the native internal mammary artery.