Viz.ai Implementation of Stroke Augmented Intelligence and Communications Platform to Improve Indicators and Outcomes for a Comprehensive Stroke Center and Network

BACKGROUND AND PURPOSE

Comprehensive stroke centers continually strive to narrow neurointerventional time metrics. Although process improvements have been put in place to streamline workflows, complex pathways, disparate imaging locations, and fragmented communications all highlight the need for continued improvement.

MATERIALS AND METHODS

This Quality Improvement Initiative (VISIION) was implemented to assess our transition to the Viz.ai platform for immediate image review and centralized communication and their effect on key performance indicators in our comprehensive stroke center. We compared periods before and following deployment. Sequential patients having undergone stroke thrombectomy were included. Both direct arriving large-vessel occlusion and Brain Emergency Management Initiative telemedicine transfer large-vessel occlusion cases were assessed as were subgroups of OnHours and OffHours. Text messaging thread counts were compared between time periods to assess communications. Mann-Whitney U and Student t tests were used.

RESULTS

Eighty-two neurointerventional cases were analyzed pre vs. post time periods: (DALVO-OnHours 7 versus 7, DALVO-OffHours 10 versus 5, BEMI-OnHours 13 versus 6, BEMI-OffHours 17 versus 17). DALVO-OffHours had a 39% door-to-groin reduction (157 versus 95 minutes, P = .009). DALVO-All showed a 32% reduction (127 versus 86 minutes, P = .006). BEMI-All improved 33% (42 versus 28 minutes, P = .036). Text messaging thread counts improved 30% (39 versus 27, P = .04).

CONCLUSIONS

There was an immediate improvement following Viz.ai implementation for both direct arriving and telemedicine transfer thrombectomy cases. In the greatest opportunity subset (direct arriving large-vessel occlusion-OffHours: direct arriving cases requiring team mobilization off-hours), we noted a 39% improvement. With Viz.ai, we noted that immediate access to images and streamlined communications improved door-to-groin time metrics for thrombectomy. These results have implications for future care processes and can be a model for centers striving to optimize workflow and improve thrombectomy timeliness.

Percutaneous Transsplenic Balloon-Assisted Transjugular Intrahepatic Portosystemic Shunt Placement in Patients with Portal Vein Obliteration for Portal Vein Recanalization: Feasibility, Safety and Effectiveness

Purpose

To assess the feasibility, safety and effectiveness of portal vein recanalization (PVR)–transjugular portosystemic shunt (TIPS) placement via splenic access using a balloon puncture technique.

Materials and Methods

In a single-center retrospective study from March 2017 to February 2021, 14 consecutive patients with portal hypertension, chronic liver disease and portal vein occlusion or near-complete (> 95%) occlusion were referred for PVR–TIPS placement. Feasibility, safety and effectiveness including procedural characteristics such as technical success, complication profile and splenic access time (SAT), balloon positioning time (BPT), conventional portal vein entry time (CPVET), overall procedure time (OPT), fluoroscopy time (FT), dose–area product (DAP) and air kerma (AK) were evaluated.

Results

Transsplenic PVR–TIPS using balloon puncture technique was technically feasible in 12 of 14 patients (8 men, 49 ± 13 years). In two patients without detectable intrahepatic portal vein branches, TIPS placement was not feasible and both patients were referred for further treatment with nonselective beta blockers and endoscopic variceal ligation. No complications grade > 3 of the Cardiovascular and Interventional Radiological Society of Europe classification system occurred. The SAT was 25 ± 21 min, CPVET was 33 ± 26 min, the OPT was 158 ± 54 min, the FT was 42 ± 22 min, the DAP was 167.84 ± 129.23 Gy*cm² and the AK was 1150.70 ± 910.73 mGy.

Conclusions

Transsplenic PVR–TIPS using a balloon puncture technique is feasible and appears to be safe in our series of patients with obliteration of the portal vein. It expands the interventional options in patients with chronic PVT.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00270-021-03054-2.

Adrenal venous sampling in primary hyperaldosteronism: correlation of hormone indices and collimated C-arm CT findings

PURPOSE

To evaluate the feasibility and effect of an approach to adrenal venous sampling (AVS) analysis by combining established selective cortisol and aldosterone indices with the acquisition of a collimated C-arm CT(CACT_Coll).

METHODS

Overall, 107 consecutive patients (45f,62 m; 54 ± 10 years) undergoing 111 AVS procedures without hormonal stimulation from 7/13 to 2/20 in a single institution were retrospectively analysed. Hormone levels were measured in sequential samples of the suspected adrenal veins and right iliac vein, and selectivity indices (SI) computed. Stand-alone SI_Cortisol and/or SI_Aldosterone ≥ 2.0 as well as SI_Cortisol and/or SI_Aldosterone ≥ 1.1 combined with positive right-sided CACT_Coll of the adrenals (n = 80; opacified right adrenal vein) were defined as a successful AVS procedure. Radiation exposure of CACT was measured via dose area product (DAP) and weighed against an age-/weight-matched cohort (n = 66).

RESULTS

Preliminary success rates (SI_Cortisol and/or SI_Aldosterone ≥ 2.0) were 99.1% (left) and 72.1% (right). These could be significantly increased to a 90.1% success rate on the right, by combining an adjusted SI of 1.1 with a positive CACT_Coll proving the correct sampling position. Sensitivity for stand-alone collimated CACT (CACT_Coll) was 0.93, with 74/80 acquired CACT_Coll confirming selective cannulation by adrenal vein enhancement. Mean DAP_{Coll_CACT} measured 2414 ± 958 μGyxm², while mean DAP_{Full-FOV_CACT} in the matched cohort measured 8766 ± 1956 μGyxm² (p < 0.001).

CONCLUSION

Collimated CACT in AVS procedures is feasible and leads to a significant increase in success rates of (right-sided) selective cannulation and may in combination with adapted hormone indices, offer a successful alternative to previously published AVS analysis algorithms with lower radiation exposure compared to a full-FOV CACT.

Percutaneous isolated hepatic perfusion (chemosaturation) with melphalan following right hemihepatectomy in patients with cholangiocarcinoma and metastatic uveal melanoma: peri- and post-interventional adverse events and therapy response compared to a matched group without prior liver surgery

To evaluate feasibility, frequency and severity of peri-procedural complications and post-procedural adverse events (AEs) in patients with advanced cholangiocarcinoma or liver metastasis of uveal melanoma and prior hemihepatectomy undergoing chemosaturation percutaneous hepatic perfusion (CS-PHP) and to analyze therapy response and overall survival compared to a matched group without prior surgery. CS-PHP performed between 10/2014 and 02/2018 were retrospectively assessed. To determine peri-procedural safety and post-procedural adverse events, hospital records and hematological, hepatic and biliary function were categorized using Common Terminology Criteria for Adverse Events (CTCAE) v5.0 (1–5; mild-death). Significance was tested using Wilcoxon signed-rank and Mann–Whitney U test. Kaplan–Meier estimation and log-rank test assessed survival. Overall 21 CS-PHP in seven patients (4/7 males; 52 ± 10 years) with hemihepatectomy (group^hemihep) and 22 CS-PHP in seven patients (3/7 males; 63 ± 12 years) without prior surgery (group^noresection) were included. No complications occurred during the CS-PHP procedures. Transient changes (CTCAE grade 1–2) of liver enzymes and blood cells followed all procedures. In comparison, group^hemihep presented slightly more AEs grade 3–4 (e.g. thrombocytopenia in 57% (12/21) vs. 41% (9/22; p = 0.37)) 5–7 days after CS-PHP. These AEs were self-limiting or responsive to treatment (insignificant difference of pre-interventional to 21–45 days post-interventional values (p > 0.05)). One patient in group^hemihep with high tumor burden died eight days following CS-PHP. No deaths occurred in group^noresection. In comparison, overall survival after first diagnosis was insignificantly shorter in group^noresection (44.7(32–56.1) months) than in group^hemihep (48.3(34.6–72.8) months; p = 0.48). The severity of adverse events following CS-PHP in patients after hemihepatectomy was comparable to a matched group without prior liver surgery. Thus, the performance of CS-PHP is not substantially compromised by a prior hemihepatectomy.

Two-dimensional parametric parenchymal blood flow in transarterial chemoembolisation for hepatocellular carcinoma: perfusion change quantification and tumour response prediction at 3 months post-intervention

AIM

To evaluate the feasibility and potential value of two-dimensional (2D) parametric parenchymal blood flow (2D-PPBF) for the assessment of perfusion changes during transarterial chemoembolisation with drug-eluting beads (DEB-TACE) and to analyse correlations of 2D-PPBF parameters and tumour response.

MATERIALS AND METHODS

Thirty-two patients (six women, 26 men, mean age: 67±8.9 years) with unresectable hepatocellular carcinoma (HCC) who underwent their first DEB-TACE were included in this study. To quantify perfusion changes using 2D-PPBF, the acquired digital subtraction angiography (DSA) series were post-processed. Ratios were calculated between the reference region of interest (ROI) and the wash-in rate (WIR), the arrival to peak (AP) and the area under the curve (AUC) of the generated time-density curves. Comparisons between pre- and post-embolisation data were made using the Wilcoxon signed-rank test. Tumour response was assessed at 3 months using the modified Response Evaluation Criteria in Solid Tumours (mRECIST) and correlated to changes of 2D-PPBF parameters.

RESULTS

All 2D-PPBF parameters derived from the ROI-based time-attenuation curves were significantly different pre-versus post-DEB-TACE. Although the AUC, the WIR and target lesion size measured in accordance with mRECIST decreased (p≤0.0001) significantly, AP values showed a significant increase (p = 0.0033). Tumour response after DEB-TACE correlated with changes in the AUC (p = 0.01, r = -0.45).

CONCLUSION

2D-PPBF offers an objective approach to analyse perfusion changes of embolised tumour tissue following DEB-TACE and can therefore be used to predict tumour response.

Evaluation of a newly developed 2D parametric parenchymal blood flow technique with an automated vessel suppression algorithm in patients with chronic thromboembolic pulmonary hypertension undergoing balloon pulmonary angioplasty

AIM

To evaluate the feasibility of two-dimensional parametric parenchymal blood flow (2D-PPBF) to quantify perfusion changes in the lung parenchyma following balloon pulmonary angioplasty (BPA) for treatment of chronic thromboembolic pulmonary hypertension.

MATERIALS AND METHODS

Overall, 35 consecutive interventions in 18 patients with 98 treated pulmonary arteries were included. To quantify changes in pulmonary blood flow using 2D-PPBF, the acquired digital subtraction angiography (DSA) series were post-processed using dedicated software. A reference region of interest (ROI; arterial inflow) in the treated pulmonary artery and a distal target ROI, including the whole lung parenchyma distal to the targeted stenosis, were placed in corresponding areas on DSA pre- and post-BPA. Half-peak density (HPD), wash-in rate (WIR), arrival to peak (AP), area under the curve (AUC), and mean transit time (MTT) were assessed. The ratios of the reference ROI to the target ROI (HPD_parenchyma/HPD_inflow, WIR_parenchyma/WIR_inflow; AP_parenchyma/AP_inflow, AUC_parenchyma/AUC_inflow, MTT_parenchyma/MTT_inflow) were calculated. The relative differences of the 2D-PPBF parameters were correlated to changes in the pulmonary flow grade score.

RESULTS

The pulmonary flow grade score improved significantly after BPA (1 versus 3; p<0.0001). Likewise, the mean HPD_parenchyma/HPD_inflow (-10.2%; p<0.0001), AP_parenchyma/AP_inflow (-24.4%; p=0.0007), and MTT_parenchyma/MTT_inflow (-3.5%; p=0.0449) decreased significantly, whereas WIR_parenchyma/WIR_inflow (+82.4%) and AUC_parenchyma/AUC_inflow (+58.6%) showed a significant increase (p<0.0001). Furthermore, a significant correlation between changes of the pulmonary flow grade score and changes of HPD_parenchyma/HPD_inflow (ρ=-0.21, p=0.04), WIR_parenchyma/WIR_inflow (ρ=0.43, p<0.0001), AP_parenchyma/AP_inflow (ρ=-0.22, p=0.03), AUC_parenchyma/AUC_inflow (ρ=0.48, p<0.0001), and MTT_parenchyma/MTT_inflow (ρ=-0.39, p<0.0001) could be observed.

CONCLUSION

The 2D-PPBF technique is feasible for the quantification of perfusion changes following BPA and has the potential to improve monitoring of BPA.

Virtual single source CT using dual source acquisition: Clinical applicability in run-off CT-angiography for intra-individual comparison of different scan protocols

PURPOSE

Virtual single source computed tomography (VSS-CT) acquisition on a dual source CT (DSCT) has been demonstrated to allow for dose-neutral intra-individual comparison of three acquisition protocols at different radiation dose levels (RDL) within one acquisition in a phantom. The purpose of this study was twofold: first to evaluate the applicability of VSS-CT in patients and second to optimize the task-dependent trade-off between radiation dose and image quality of lower extremity CT angiography (run-off CTA).

MATERIAL AND METHODS

In this IRB-approved prospective study 52 patients underwent run-off CTA between 06/2012 and 06/2013. VSS-CT acquisition was conducted using a first generation DSCT applying equal X-ray tube settings (120 kVp), collimation (2 × 32 × 0.6 mm), and slice thickness (1.0 mm) but different effective tube current-time products (tube A: 80 mAs, tube B: 40 mAs). Three different image datasets representing three different radiation dose levels (RDL40, RDL80, RDL120) were reconstructed using a soft kernel from the raw data of tube B, tube A or both tubes combined. Dose length products (DLP) of each raw data set were documented. Quantitative image quality (IQ) was assessed for five anatomical levels using image noise and contrast-to-noise ratio (CNR). To investigate dose efficiency of each acquisition, the dose-weighted CNR (CNRD) was determined. Qualitative IQ was evaluated by two blinded readers in consensus using a 5-point Likert scale and compared with a Friedman- and posthoc Wilcoxon test.

RESULTS

Mean DLP was 200 ± 40, 400 ± 90 and 600 ± 130 mGy·cm for the RDL40, RDL80 and RDL120, respectively. Image noise and CNR were best for RDL120 and decreased significantly for RDL80 and RDL40, independent of the anatomic level (p < 0.001). CNRD showed no significant differences at the abdominal and pelvic level between the investigated radiation dose levels. However, for thigh to foot level a significant increase of CNRD was noted between RDL120, RDL80 and RDL40. Significant differences of qualitative IQ were observed between RDL120 and RDL40 from the abdominal to the foot level, whereas no difference was seen for the other dose levels.

CONCLUSION

Radiation dose splitting with VSS-CT can be applied to run-off CTA facilitating intra-individual comparison of different acquisition protocols without additional radiation exposure. Furthermore, a radiation dose reduction potential for run-off CTA of approximately 1/3 as compared to the acquisition protocol recommended by the manufacturer could be identified in this study.

Factors Influencing Acute Stroke Thrombolytic Treatments in Hispanics In the San Diego Region

BACKGROUND

Since the introduction of recombinant tissue plasminogen activator (rt-PA) for acute ischemic stroke, rt-PA rate and number of stroke centers have increased. Despite this, studies have shown racial and ethnic disparities in stroke care especially in Black and Hispanic populations. What factors are related to the administration of rt-PA within the Hispanic population has to date been unclear.

METHODS

We performed a retrospective review of IRB approved, prospectively collected data from the UC San Diego Stroke Registry from 7/2004-7/2016. Patients were included based on the primary diagnosis of Transient Ischemic Attack or Ischemic Stroke. Hispanic vs non-Hispanic patients were compared to assess for overall rt-PA treatment rates and process of care intervals. For the Hispanic cohort itself, demographics and NIHSS scores were assessed to determine why some Hispanics received rt-PA while others were not.

RESULTS

Overall, 1489 patients (300 Hispanic vs. 1189 non-Hispanic) were included. Comparing Hispanics to non-Hispanics, there was no difference in rt-PA rate (35.3% vs. 33.1%; p=0.49). In rt-PA treated patients, "onset to arrival" interval was higher in Hispanics (1.03 vs. 0.88 hours; p=0.04), while the "arrival to treatment" interval was not different (1.13 vs. 1.02 hours; p=0.07). When looking at Hispanic patients only, there was no difference in baseline characteristics except for initial NIHSS in treated vs. non-treated patients (13.27 vs. 7.24; p<.001).

CONCLUSION

Our analyses sought to determine the factors important to administration of rt-PA to Hispanic patients. These findings highlight the need for strategies to improve recognition and presentation pathways for Hispanics.

Non-enhanced CT Maximum Intensity Projections for the Detection of Large Vessel Occlusions

BACKGROUND

Identification of large vessel occlusions (LVO) is important with recent guidelines supporting endovascular therapy in selected acute ischemic stroke patients. Many stroke centers perform CT angiography (CTA) in patients with suspected LVO, however this requires additional time and contrast administration. Non-enhanced CT maximum intensity projection (NECT-MIPs) may offer a rapid alternative to CTA.

METHODS

We retrospectively reviewed acute stroke patients with LVO in the UCSD Stroke Registry, presenting between 6/2014-7/2016. NECT-MIPs were evaluated for presence of LVO. Gold standard comparison was to CTA. Results were stratified by level of training (Faculty, Fellow and Acute Care Practitioners [ACPs]). Inter-rater agreement was assessed using Fleiss' Kappa Coefficient.

RESULTS

We reviewed 24 patients using NECT-MIPs for the detection of LVO. Faculty had a sensitivity and specificity of 95% & 92% for ICA/M1, 42% & 100% for M2, and 67% & 96% for basilar occlusions. Fellows and ACPs had a sensitivity and specificity of 61% & 94% for ICA/M1, 19% & 83% for M2, and 75% & 95% for basilar occlusions. Inter-rater agreement among Faculty readers was k=0.75 for ICA/M1, k=0.79 for M2 and k=0.14 for basilar occlusions. Among Fellows and ACPs, k=0.57 for ICA/M1, k=0.40 for M2, and k=0.27 for basilar occlusions.

CONCLUSIONS

NECT-MIPs have high sensitivity and specificity for the detection of LVO when compared to CTA. Inter-rater agreement is fair and higher amongst more experienced reviewers. These results suggest that NECT-MIPs may be helpful to streamline the identification of LVO and reduce door to needle and door to intervention times.

The coherent radiation fraction of low-emittance synchrotrons

In this work the coherence properties of the synchrotron radiation beam from an X-ray undulator in a fourth-generation storage ring are analyzed. A slightly focused X-ray beam is simulated using a wavefront propagation through a non-redundant array of slits and the mutual coherence function is directly obtained and compared with the Gaussian-Schell approximation. The numerical wave propagation and the approximate analytical approaches are shown to agree qualitatively, and it is also shown that, when the coherent fraction is selected by a finite aperture before the focusing element, even achromatic focusing systems like total reflection mirrors become slightly chromatic. This effect is also well accounted for in the Gaussian-Schell model. The wavefront propagation simulation through the non-redundant array was repeated with an imperfect mirror demonstrating that, although the wavefront is distorted, its coherent length is practically unchanged.

[Chronic thromboembolic pulmonary hypertension: Recommendations of the Cologne Consensus Conference 2016]

The 2015 European Guidelines on Pulmonary Hypertension did not cover only pulmonary arterial hypertension (PAH), but also other significant subgroups of pulmonary hypertension (PH). In June 2016, a Consensus Conference organized by the PH working groups of the German Society of Cardiology (DGK), the German Society of Respiratory Medicine (DGP) and the German Society of Pediatric Cardiology (DGPK) was held in Cologne, Germany to discuss open and controversial issues surrounding the practical implementation of the European Guidelines. Several working groups were initiated, one of which was dedicated to the diagnosis and treatment of chronic thromboembolic pulmonary hypertension (CTEPH). In every patient with PH of unknown cause CTEPH should be excluded. The primary treatment option is surgical pulmonary endarterectomy (PEA) in a specialized multidisciplinary CTEPH center. Inoperable patients or patients with persistent or recurrent CTEPH after PEA are candidates for targeted drug therapy. For balloon pulmonary angioplasty (BPA), there is currently only limited experience. This option - as PEA - is reserved to specialized centers with expertise for this treatment method. In addition, a brief overview is given on pulmonary artery sarcoma, since its surgical treatment is often analogous to PEA. The recommendations of this working group are summarized in the present paper.

C-arm CT--an adjunct to DSA for endoleak classification in patients with endovascular repair of abdominal aortic aneurysms

PURPOSE

To assess the benefit of C-arm CT for classification and procedural guidance during interventional therapy of endoleaks (EL) after endovascular repair (EVAR) of abdominal aortic aneurysms (AAA).

MATERIALS AND METHODS

12 patients with EL diagnosed with CT but undetermined EL classification (ELC) underwent DSA and transarterial contrast-enhanced C-arm CT. ELC (based on DSA, C-arm CT and CT) assessed during the angiographic procedure served as the standard of reference (SOR). Subsequently, ELC was assessed by a blinded second reader based on DSA or C-arm CT and compared to the SOR. In the case of an interventional procedure (n = 6), the added value of C-arm CT for procedure guidance was assessed retrospectively (1: essential, 2: helpful, 3: additional information without impact, 4: no additional information).

RESULTS

The blinded reader classified 9/12 EL using DSA alone and 11/12 EL using C-arm CT alone. In one patient, the temporal resolution provided by DSA was essential to establish the diagnosis. In 6 patients, a type 2 EL without need for therapy was diagnosed. The remaining 6 patients showed EL that were treated immediately (type 1 EL, n = 4: 3 stent graft extensions and one angioplasty; type 2 EL, n = 1: translumbar embolization; type 3 EL, n = 1: sealing of a fabric tear). The information provided by C-arm CT was assessed to be essential in three patients and helpful in two.

CONCLUSION

C-arm CT is an ideal adjunct to DSA. In our pilot study, it helped to localize and classify endoleaks more reliably than DSA alone.

The modified National Institutes of Health Stroke Scale: its time has come

The National Institutes of Health Stroke Scale (NIHSS) is a well known, reliable and valid stroke deficit scale. The NIHSS is simple, quick, and has shown significant reliability in diverse groups, settings, and languages. The NIHSS also contains items with poor reliability and redundancy. Recent investigations (include assessing a new training DVD, analyzing webbased or videotape certifications, and testing foreign language versions) have further detailed reliability issues. Items recurrently shown to have poor reliability include Level of Consciousness, Facial Palsy, Limb Ataxia, and Dysarthria. The modified NIHSS (mNIHSS) minimizes redundancy and eliminates poorly reliable items. The mNIHSS shows greater reliability in multiple settings and cohorts, including scores abstracted from records, when used via telemedicine, and when used in clinical trials. In a validation of the mNIHSS against the NIHSS, the number of elements with excellent agreement increased from 54% to 71%, while poor agreement decreased from 12% to 5%. Overall, 45% of NIHSS items had less than excellent reliability vs. only 29% for the mNIHSS. The mNIHSS is not the ideal stroke scale, but it is a significant improvement over the NIHSS. The mNIHSS has shown reliability at bedside, with record abstraction, with telemedicine, and in clinical trials. Since the mNIHSS is more reliable, it may allow for improved practitioner communication, improved medical care, and refinement of trial enrollments. The mNIHSS should now serve as the primary stroke clinical deficit scale for clinical and research aims. When it comes to the mNIHSS, its time has come!

[Flat-detector CT-based electromagnetic navigation]

Flat-detector CT coupled to an angiography device provides an imaging technique for interventions which can be used for electromagnetically navigated percutaneous punctures. This report explains the functionality of an electromagnetic navigation system and describes the course of an electromagnetically navigated puncture and the capabilities of such a system in the clinical routine.

[C-arm CT for planning and guidance of extrahepatic embolizations]

Interventional radiological vascular embolizations are complex procedures that require exact imaging of the target region to facilitate safe and effective treatment. The purpose of this paper is to present the technique and feasibility of flat detector C-arm computed tomography (C-arm CT) for control and guidance of extrahepatic abdominal embolization procedures. C-arm CT images can provide important information on both vascular and cross-sectional anatomy of the target region, help in determining therapy endpoints and provide follow-up during and immediately after the abdominal interventions.The cases presented demonstrate that C-arm CT images are beneficial for abdominal embolization procedures and facilitate precise treatment.

The MX2 macromolecular crystallography beamline: a wiggler X-ray source at the LNLS

The Brazilian Synchrotron Light Laboratory [Laboratório Nacional de Luz Síncrotron (LNLS), Campinas, SP, Brazil] is the first commissioned synchrotron light source in the southern hemisphere. The first wiggler macromolecular crystallography beamline (MX2) at the LNLS has been recently constructed and brought into operation. Here the technical design, experimental set-up, parameters of the beamline and the first experimental results obtained at MX2 are described. The beamline operates on a 2.0 T hybrid 30-pole wiggler, and its optical layout includes collimating mirror, Si(111) double-crystal monochromator and toroidal bendable mirror. The measured flux density at the sample position at 8.7 eV reaches 4.8 x 10(11) photons s(-1) mm(-2) (100 mA)(-1). The beamline is equipped with a MarResearch Desktop Beamline Goniostat (MarDTB) and 3 x 3 MarMosaic225 CCD detector, and is controlled by a customized version of the Blu-Ice software. A description of the first X-ray diffraction data sets collected at the MX2 LNLS beamline and used for macromolecular crystal structure solution is also provided.

Prospective reliability of the STRokE DOC wireless/site independent telemedicine system

The authors evaluated a site-independent telemedicine system. Telemedicine may be limited by the need for fixed connectivity. Wireless and site-independent technologies eliminate this limitation. Twenty-five stroke patients underwent evaluations by remote and bedside examiners. Ten of 15 (67%) NIH Stroke Scale and 9 of 11 (82%) Modified NIH Stroke Scale items showed excellent interrater reliability. Spearman correlations were > or =0.93. This Internet system is reliable and valid. Further studies should assess its use in acute stroke.

Becken-Bein-CT-Angiographie mit der 16-Zeilen-Multislice-Technik: Kontrastmittel-Enhancement und Bildqualität unter Einsatz eines standardisierten Untersuchungsprotokolls

PURPOSE

To assess the degree of enhancement and image quality of 16-slice multidetector CT angiography (MDCTA) of pelvic and lower limb arteries with a monophasic contrast medium injection protocol.

MATERIALS AND METHODS

Fifty patients underwent a CT angiography of the pelvic and lower limb arteries using the following parameters: collimation 16 x 1.5 mm, rotation time 0.5 s, table feed 40 mm/sec, slice thickness 2 mm, reconstruction interval 1.2 mm, 100 ml Iomeprol 400 + 60 ml normal saline, flow rate 4 ml/s, bolus tracking (threshold of 250 DeltaHU in aorta). Arterial enhancement was measured in all arterial segments. Maximum intensity projections (MIP) together with axial images were reviewed by two radiologists (consensus). If the results were inconclusive for stenosis, additional curved multiplanar reformations (MPR) were performed.

RESULTS

The mean arterial enhancement values were aorta: 314 +/- 69, pelvis: 342 +/- 105, thigh: 347 +/- 139, calf: 231 +/- 109 DeltaHU. The image quality was judged as excellent in 346 (77.6 %), adequate in 76 (17 %), and inadequate in 24 (5.4 %, all but one in calf and foot) of 446 arterial territories. An override of the contrast bolus below the knee occurred in 2 patients rendering the calf arteries nondiagnostic. Venous enhancement occurred in 13 patients but this compromised the diagnostic assessment in only one case. Additional MPRs were required accurately to assess stenoses in 22 of 200 arterial levels in 16 patients with marked arterial calcifications.

CONCLUSION

16-slice MDCTA with a monophasic contrast bolus of Iomeprol 400 provided good arterial enhancement and diagnostic image quality in 94.6 % of the depicted arterial segments. The majority (67 %) of nondiagnostic segments were below the ankle. MPRs were required in patients with marked calcification for accurate assessment of stenosis.

Mild gait abnormality and leg discomfort in a child secondary to extradural ganglioneuroma

Ganglioneuromas are benign and slow-growing tumors that most commonly originate from the sympathetic trunk. Ganglioneuromas often decrease in size and rarely require reoperation. Changes in gait or the onset of limb pain without a discernible local cause are indications for investigation of patients for possible intraspinal pathology. We report the case of a 5-year-old boy who presented with seemingly static symptoms, while the slow-growing tumor had enveloped nerve roots and caused bone destruction of the vertebrae.

Diagnostic tests for Helicobacter pylori: a prospective evaluation of their accuracy, without selecting a single test as the gold standard

OBJECTIVE

To assess the accuracy of six commonly used diagnostic tests for Helicobacter pylori in a prospective study without using any specific test as the gold standard (the patient was regarded as H. pylori-infected if two or more tests, whatever their nature, were positive).

METHODS

In 105 outpatients undergoing upper GI endoscopy, 62 without significant abnormalities, 28 with gastroesophageal reflux disease, 19 with peptic ulcer, one with erosive gastritis, and one with atrophic gastritis (some patients had more than one diagnosis), antral biopsy specimens were taken for culture, polymerase chain reaction, histological examination (hematoxylineosin and Giemsa stains), and rapid urease test. Corpus biopsy specimens were taken for histological examination. Serology (ELISA) and a 13C-urea breath test were also performed. Consistency of diagnosis between two pathologists was assessed by kappa statistics.

RESULTS

Sensitivity and specificity, respectively, were as follows: culture, 98.4 and 100%; polymerase chain reaction, 96.7 and 100%; histological examination (antrum), 96 and 98.8%; histological examination (antrum + corpus), 98.4 and 98.8%; rapid urease test, 90.2 and 100%; 13C-urea breath test, 100 and 100%; and serological examination, 98.4 and 88.4% (95% in those who had not been previously treated for H. pylori). All H. pylori-positive cases were detected by culture and rapid urease test. In 86.4% of these cases all antral biopsy-based tests were positive. Agreement between pathologists was good, with a kappa coefficient around 0.90 for antral biopsy specimens.

CONCLUSIONS

All antral biopsy-based tests, as well as the 13C-urea breath test, are accurate for the diagnosis of H. pylori infection. Sampling error is a problem of minor importance. The lower specificity of serological tests may be largely explained by previous treatment of H. pylori.

The effects of matrix compression on proteoglycan metabolism in articular cartilage explants

The effects of compressive stress on the rate of proteoglycan synthesis and release were determined in bovine articular cartilage from 4-5-month-old animals. Full depth cartilage explants were compressed in an unconfined configuration at various stresses ranging up to 1.0 MPa. At mechanical equilibrium (after 24 h), no significant changes were detected in the rate of [35S]-sulfate (35SO4) incorporation at the low level of compressive stresses used (less than 0.057 MPa). At an intermediate level of compressive stress (0.057, 0.1, 0.5 MPa), 35SO4 incorporation rates were reduced to approximately 60% of control values. At the highest level compressive stress (1.0 MPa) studied, 35SO4 incorporation rates were further reduced to approximately 20% that of controls. Recovery experiments at intermediate stress levels showed increased rates of 35SO4 incorporation at 24 h after compression. In explants loaded for 24 h at stresses of 0.1 MPa or higher, there was a stress-dose dependent inhibition of proteoglycan release into the media (up to 61% at 1.0 MPa), and proteoglycan release rates did not return to control values following a 24 h recovery period. While cartilage composition and biosynthetic activity were found to vary significantly with depth in control cartilage, the observed suppression (% change) in biosynthetic activity was relatively uniform with depth in both loading and recovery experiments. The study indicates that compression of the tissue to physiological strain magnitudes serves as a signal to modulate chondrocyte biosynthetic and catabolic responses through the depth of cartilage, while prolonged compression at higher strains may be responsible for tissue and cell damage.

Fc receptor-mediated phagocytosis occurs in macrophages at exceedingly low cytosolic Ca2+ levels

Cytosolic free Ca2+ ([Ca2+]i) homeostasis was investigated in mouse peritoneal macrophages and in the macrophage-like cell line J774. [Ca2+]i measurements were performed in both cells in suspension and cells in monolayers loaded with either quin2 or fura-2. Resting [Ca2+]i was 110-140 and 85-120 nM for cell suspensions and monolayers, respectively. There were no significant differences in [Ca2+]i between the two macrophage populations whether quin2 or fura-2 were used as Ca2+ indicators. Addition of heat-aggregated IgG, IgG-coated erythrocyte ghosts, or a rat monoclonal antibody (2.4G2) directed against mouse Fc receptor II induced a rise in [Ca2+]i. This [Ca2+]i increase was consistently observed in J774 and peritoneal macrophage suspensions and in J774 macrophage monolayers; in contrast it was observed inconsistently in peritoneal macrophages in monolayer cultures. The increase in [Ca2+]i induced by ligation of Fc receptors was inhibited totally in macrophages in suspension and by 80% in macrophages in monolayers by a short preincubation of macrophages with PMA; however, phagocytosis itself was unaffected. The effect of reducing cytosolic Ca2+ to very low concentrations on Fc receptor-mediated phagocytosis was also investigated. By incubating macrophages with high concentrations of quin2/AM in the absence of extracellular Ca2+, or by loading EGTA into the cytoplasm, the [Ca2+]i was buffered and clamped to 1-10 nM. Despite this, the phagocytosis of IgG-coated erythrocytes proceeded normally. These observations confirm the report of Young et al. (Young, J. D., S. S. Ko, and Z. A. Cohn. 1984. Proc. Natl. Acad. Sci. USA. 81:5430-5434) that ligation of Fc receptors causes Ca2+ mobilization in macrophages. However, these results confirm and extend the findings of McNeil et al. (McNeil, P. L., J. A. Swanson, S. D. Wright, S. C. Silverstein, and D. L. Taylor. 1986. J. Cell Biol. 102:1586-1592) that a rise in [Ca2+]i is not required for Fc receptor-mediated phagocytosis; and they provide direct evidence that Fc receptor-mediated phagocytosis occurs normally even at exceedingly low [Ca2+]i.

Notes on the uses of psychoanalysis for biography

It is the dual aim of this presentation to explore the scope and to define the limits of what psychoanalysis can offer to the field of biography. In pursuit of these goals emphasis is placed upon the influence of the writer's emotional attachment to his subject, which, despite intensive psychoanalytic training and experience, may compromise his objectivity and contaminate his narrative. In addition, attention is drawn to psychological issues in the life of the creative artist which may play a decisive role both in determining the quality of his work and in stimulating its production.

Rubella virus cDNA. Sequence and expression of E1 envelope protein

A cDNA clone encoding the entire E1 envelope protein (410 amino acid residues) and a portion of the C-terminal end of the E2 envelope protein of the rubella virus has been isolated and characterized. DNA sequence analysis has revealed a region 20 nucleotides in length at the 3' end of the cloned cDNA which may be a replicase recognition site or a recognition site for encapsidation. The proteolytic cleavage site between the E1 and E2 proteins was localized based on the known amino-terminal sequence of the isolated E1 protein (Kalkkinen, N., Oker-Blom, C., and Pettersson, R. F. (1984) J. Gen. Virol. 65, 1549-1557) and the deduced amino acid sequence. The mature E1 protein is preceded by a set of 20 highly hydrophobic amino acid residues possessing characteristics of a signal peptide. This "signal peptide" is flanked on both sides by typical protease cleavage sites for trypsin-like enzyme and signal peptidase. The presence of a leader sequence in the E1 protein precursor may facilitate its translocation through the host cell membrane. The E1 protein of rubella virus shows no significant homology with alphavirus E1 envelope proteins. However, a stretch of 39 amino acids in the E1 protein of rubella virus (residues 262-300) was found to share a significant homology with the first 39 residues of bovine sperm histone. The position of 4 half-cystines and 8 arginines overlaps. The E1 protein of rubella virus has been successfully expressed in COS cells after transfecting them with rubella virus cDNA in simian virus 40-derived expression vector. This protein is antigenically similar to the one expressed by cells infected with rubella virus.

Remarks on the etiology of Gilles de la Tourette's syndrome

Utilizing a case of Tourette's syndrome as an illustration, this paper seeks to refine the problem of causality in medical illness. In contrast to numerous examples reported in the literature, the patient presented in this communication, a 26-year-old man afflicted with tics, convulsive movements, intractable vomiting, and coprolalia, failed to respond favorably to medication, although he showed marked improvement in the course of psychotherapy. Despite rather transparent psychodynamic connections between his life history on the one hand and the nature and vicissitudes of his symptomatology on the other, it cannot be concluded that the psychological factors alone can account for the clinical picture; at best they may be regarded as contributory, as opposed to necessary or sufficient causes, a distinction that may be applied to other conditions as well. This report includes a review of some of the literature on Tourette's syndrome, with special emphasis on the case of Dr. Samuel Johnson, who in retrospect appears to have been a likely victim of that unfortunate malady.

Interferon-gamma depresses binding of ligand by C3b and C3bi receptors on cultured human monocytes, an effect reversed by fibronectin

Cultivation of human monocytes with recombinant IFN-gamma causes a 5-10-fold depression in their binding of EC3b or EC3bi. This effect is observed within 18 h and is expressed for 5 d in the presence of 100 U/ml IFN-gamma. The capacity of IFN-gamma-treated phagocytes to bind EC3b and EC3bi is fully restored if the phagocytes are allowed to spread for 45 min on surfaces coated with Fn. IFN-gamma-treated cells express normal levels of cell surface C3b and C3bi receptors as measured with monoclonal anti-receptor antibodies, and spreading on Fn does not alter receptor number. We conclude that cultivation with IFN-gamma causes a change in the nature of these receptors that prevents them from interacting with ligand. Immunoelectron microscopy shows that C3bi receptors are expressed on the apical surface of the IFN-gamma-treated MO and that these receptors exhibit normal capacity to migrate in the plane of the membrane. Thus, the nature of the change caused by IFN-gamma is not related to changes in receptor number, location, or mobility. While spreading of IFN-gamma-treated cells on Fn enables C3 receptors to bind ligand, it does not enable them to promote phagocytosis. Treatment of cells with PMA alone does not affect binding or phagocytosis, but treatment of cells with both Fn and PMA enables cells to phagocytose EC3b and EC3bi. These data indicate that the binding and signaling activities of C3 receptors are separately regulated. Fn enables receptors to bind ligand and PMA enables them to signal phagocytosis.