Evaluation of clinical parallel workflow in online adaptive MR-guided Radiotherapy: A detailed assessment of treatment session times

Introduction

Advancements in MRI-guided radiotherapy (MRgRT) enable clinical parallel workflows (CPW) for online adaptive planning (oART), allowing medical physicists (MPs), physicians (MDs), and radiation therapists (RTTs) to perform their tasks simultaneously. This study evaluates the impact of this upgrade on the total treatment time by analyzing each step of the current 0.35T-MRgRT workflow.

Methods

The time process of the workflow steps for 254 treatment fractions in 0.35 MRgRT was examined. Patients have been grouped based on disease site, breathing modality (BM) (BHI or FB), and fractionation (stereotactic body RT [SBRT] or standard fractionated long course [LC]). The time spent for the following workflow steps in Adaptive Treatment (ADP) was analyzed: Patient Setup Time (PSt), MRI Acquisition and Matching (MRt), MR Re-contouring Time (RCt), Re-Planning Time (RPt), Treatment Delivery Time (TDt). Also analyzed was the timing of treatments that followed a Simple workflow (SMP), without the online re-planning (PSt + MRt + TDt.).

Results

The time analysis revealed that the ADP workflow (median: 34 min) is significantly (p < 0.05) longer than the SMP workflow (19 min). The time required for ADP treatments is significantly influenced by TDt, constituting 40 % of the total time. The oART steps (RCt + RPt) took 11 min (median), representing 27 % of the entire procedure. Overall, 79.2 % of oART fractions were completed in less than 45 min, and 30.6 % were completed in less than 30 min.

Conclusion

This preliminary analysis, along with the comparative assessment against existing literature, underscores the potential of CPW to diminish the overall treatment duration in MRgRT-oART. Additionally, it suggests the potential for CPW to promote a more integrated multidisciplinary approach in the execution of oART.

A new invasive method to assess pulse wave velocity during cardiac catheterization

 

Pulse wave velocity (PWV) is an independent cardiovascular risk factor (CVRF), and there are multiple ways to measure it with more or less accuracy.

We sought to easily develop an invasive gold standard axial PWV during cardiac catheterization between ascending aorta (AAo) and tibial artery (TIB) or humeral artery (HUM). Aorto-humeral PWV is not a usual measurement site because of its difficulty to estimate it non-invasively. Axial PWV demonstrates a greater correlation with CVRF, with carotid-femoral PWV the common way to estimate it non-invasively in hypertensive patients and others.

Methods

26 patients were enrolled for AAo-TIB PWV measurements and 50 for AAo-HUM. A cuff connected to the hemodynamic Phillips workstation of the cathlab was placed around the right leg, at mid-calf, and was inflated to superimpose TIB pulsatile blood pressure waves on AAo blood pressure recorded with a fluid filled diagnostic 5 Fr or interventional 6 Fr catheter left at the end of the diagnostic coronary angiography in the ascending aorta. The distance between AAo and TIB was estimated by the distance between axillary and iliac crest, added with the distance between iliac crest and mid-calf. PWV was then calculated from the length estimated between AAo and mid-calf, and the time delay between AAo and TIB pulses (see figure) by gating to the R-wave of the ECG (upper trace) for both measurements, using a dedicated software written in MatLab®. For AAo=HUM PWV, in 50 patients the pressure of the catheter was sequencially recorded in the AoAsc then pulled back in the humeral artery. Both recordings were matched off-line based on the R top of the ECG recorded and the delay between the rise of the 2 pressure curves in the same MatLab® software.

Results

Mean age of our patients is 62,7±9,2 years. 82% had chronic hypertension and 33% had diabetes mellitus. 4 patients (15%) had clinical peripheral artery disease and only one had a stenting on femoral artery. No patients had previous vascular bypass.

Aorto-tibial PWV showed an average PWV at 8.4±1.4 m/s. Aorto-humeral PWV showed an average PWV at 7.2±1.8 m/s. The PWV tended to be 0,6 m/s lower in patients with ≤2 cardiovascular risk factors versus &gt;3.

Conclusion

We describe a simple and accurate PWV gold standard that can be recorded in any patient admitted for a coronary angiography. Aorto-tibial PWV is easier to obtain. Adding this parameter in the global assessment of patients with hypertension or other CVD will refine their CVRF profile.

Funding Acknowledgement

Type of funding sources: None.

P799A new invasive validation method for non-invasive central blood pressure measurement using a suprasystolic sphygmomanometer

Background

Central blood pressure (cBP) is a better predictor of the damage caused by hypertension in comparison with peripheral blood pressure (pBP). Although challenging to measure, numerous devices are trying to reliably estimate cBP non-invasively. Pulse wave velocity (PWV) is another important independent cardiovascular risk factor.

Aim

We sought to deploy a new validation method using a high-fidelity pressure wire as the invasive gold standard measurement for sphygmomanometer devices estimating cBP. Moreover, we invasively calculated the PWV to investigate its relationship to the non-invasively estimated cBP.

Methods

In 50 patients requiring a cardiac catheterization, we measured the blood pressure in the ascending aorta (AAo) with a fluid-filled (FF) guiding catheter (NaCl 0,9%). We compared these values with the results derived simultaneously with a novel sphygmomanometer that estimates cBP from the analysis of brachial artery suprasystolic pressure waves, based on the pressure-wave propagation of a water-hammer acoustic model. This was measured on the left arm with the BP+ device from USCOM Pty Ltd (Sydney, NSW, Australia) while the catheterization was performed via the right radial artery. On 14 of these patients so far, we placed a 0.014" high-fidelity pressure wire in the AAo to measure cBP, when it was clinically indicated to evaluate one or more coronary stenosis by Fractional Flow Reserve (FFR). Ultimately, the wire was pulled back into the humeral artery (HUM). PWV was then calculated from the length of the pullback and the time delay between AAo and HUM pulses by gating to the R-wave of the ECG for both measurements, using MatLab software.

Results

Bland-Altman analysis of the sphygmomanometrically estimated cBPsys and the measured one by a FFR wire (left on figure) demonstrates less scatter than with the FF catheter (right). The mean difference with the sphygmomanometrically derived cBPsys was −1.2±4.7 mmHg (CI95%: −3.8; 1.8) for the FFR wire and 6.0±9.8 mmHg (CI95%: 3.2; 8.9) for the FF catheter. Central diastolic and mean BP were both overestimated by the sphygmomanometer, with respectively −7.8±6.8 mmHg (CI95%: −11.4; −4.2) and −5.5±6.1 mmHg (CI95%: −8.6; −2.3) compared to the FFR wire and −10.3±6.7 mmHg (CI95%: −12.2; −8.3) and −5.5±6.5 (CI95% : −7.3; −3.6) for the FF catheter. The average PWV was 7.0±1.4 m/s. No significant relationship of PWV and cBP was identified (p=0.189). The PWV was 0.8 m/s lower in patients with only one cardiovascular risk factor versus more than one, but without reaching statistical significance.

cBPsys measured. A. FFR; B. FluidF vs BP+

Conclusions

Using a FFR wire in the AAo as a high-fidelity pressure reference, we demonstrated that cBPsys derived from this new sphygmomanometer was accurate, with a non-significant bias (<5mmHg) and high precision (standard deviation <8mmHg) as recommended, criteria not met using the FF guiding catheter measurements. PWV measurements were also easily obtained from the FFR wire method.

Eradication therapy with rabeprazole versus omeprazole in the treatment of active duodenal ulcer

BACKGROUND

Rabeprazole has been demonstrated to be a potent antisecretory agent and has been shown to be clinically effective in the treatment of acid-related diseases.

AIMS

It was to determine the efficacy of rabeprazole at 20 and 40 mg in addition to amoxicillin and clarithromycin in the treatment of active Helicobacter pylori-positive duodenal ulcers compared with omeprazole 40 mg.

PATIENTS AND METHODS

One hundred and twenty-seven patients were randomised into three treatment groups: 40 patients were treated with rabeprazole 40 mg daily, 42 patients with rabeprazole 20 mg daily and 45 patients with omeprazole 40 mg daily for 10 days. All patients received amoxicillin 1 g twice a day and clarithromycin 500 mg twice a day for 5 days. All patients were re-assessed at least 4 weeks after the end of the treatment.

RESULTS

According to the intention-to-treat (ITT) protocol, ulcer healing was observed in 90% of patients in the rabeprazole 40 group, in 85.7% in the rabeprazole 20 group and in 93.3% in the omeprazole 40 group. We observed H. pylori eradication in 90% ITT in the rabeprazole 40 group, in 80.9% ITT in the rabeprazole 20 group and in 88.8% ITT in the omeprazole 40 group. Statistical analysis did not show significant differences among the three groups.

CONCLUSIONS

A 10-day rabeprazole 20 mg regimen represents an efficacious and safe regimen for H. pylori eradication and ulcer healing.

Characterization of the vasculogenic block in the absence of vascular endothelial growth factor-A

Vascular endothelial growth factor (VEGF) signaling is required for both differentiation and proliferation of vascular endothelium. Analysis of differentiated embryonic stem cells with one or both VEGF-A alleles deleted showed that both the differentiation and the expansion of endothelial cells are blocked during vasculogenesis. Blood island formation was reduced by half in hemizygous mutant VEGF cultures and by 10-fold in homozygous mutant VEGF cultures. Homozygous mutant cultures could be partially rescued by the addition of exogenous VEGF. RNA levels for the endothelial adhesion receptors ICAM-2 and PECAM were reduced in homozygous mutant cultures, but ICAM-2 RNA levels decreased substantially, whereas PECAM RNA levels remained at hemizygous levels. The quantitative data correlated with the antibody staining patterns because cells that were not organized into vessels expressed PECAM but not ICAM-2. These PECAM+ cell clumps accumulated in mutant cultures as vessel density decreased, suggesting that they were endothelial cell precursors blocked from maturation. A subset of PECAM+ cells in clumps expressed stage-specific embryonic antigen-1 (SSEA-1), and all were ICAM-2(-) and CD34(-), whereas vascular endothelial cells incorporated into vessels were PECAM(+), ICAM-2(+), CD34(+), and SSEA-1(-). Analysis of flk-1 expression indicated that a subset of vascular precursor cells coexpressed PECAM and flk-1. These data suggest that VEGF signaling acts in a dose-dependent manner to affect both a specific differentiation step and the subsequent expansion of endothelial cells. (Blood. 2000;95:1979-1987)

A randomized study comparing methylprednisolone plus chlorambucil versus methylprednisolone plus cyclophosphamide in idiopathic membranous nephropathy

To assess whether chlorambucil or cyclophosphamide may have a better therapeutic index in patients with idiopathic membranous nephropathy, we compared two regimens based on a 6-mo treatment, alternating every other month methylprednisolone with chlorambucil or methylprednisolone with cyclophosphamide. Patients with biopsy-proven membranous nephropathy and with a nephrotic syndrome were randomized to be given methylprednisolone (1 g intravenously for 3 consecutive days followed by oral methylprednisolone, 0.4 mg/kg per d for 27 d) alternated every other month either with chlorambucil (0.2 mg/kg per d for 30 d) or cyclophosphamide (2.5 mg/kg per d for 30 d). The whole treatment lasted 6 mo; 3 mo with corticosteroids and 3 mo with one cytotoxic drug. Among 87 patients followed for at least 1 yr, 36 of 44 (82%; 95% confidence interval [CI], 67.3 to 91.8%) assigned to methylprednisolone and chlorambucil entered complete or partial remission of the nephrotic syndrome, versus 40 of 43 (93%; 95% CI, 80.9 to 98.5%) assigned to methylprednisolone and cyclophosphamide (P = 0.116). Of patients who attained remission of the nephrotic syndrome, 11 of 36 in the chlorambucil group (30.5%) and 10 of 40 in the cyclophosphamide group (25%) had a relapse of the nephrotic syndrome between 6 and 30 mo. The reciprocal of plasma creatinine improved in the cohort groups followed for 1 yr for both treatment groups (P < 0.01) and remained unchanged when compared with basal values in the cohort groups followed for 2 and 3 yr. Six patients in the chlorambucil group and two in the cyclophosphamide group did not complete the treatment because of side effects. Four patients in the chlorambucil group but none in the cyclophosphamide group suffered from herpes zoster. One patient per group developed cancer. It is concluded that in nephrotic patients with idiopathic membranous nephropathy both treatments may be effective in favoring remission and in preserving renal function for at least 3 yr.

[Treatment of stage IV breast carcinoma]

The authors report a study carried out in 4 patients with stage 4 breast cancer. The treatment protocol was selected according to age and the general conditions of patients. Two out of four patients were treated with adjuvant chemotherapy associated with cyclophosphamide, adriblastin, 5-fluorouracil and folic acid; one patient received neoadjuvant chemotherapy with the same treatment protocol, while the fourth patient was treated with hormone and immunotherapy. Results were satisfying given that survival was considerably increased in 3 patients together with an improvement in general conditions.

[Venereal perihepatitis: Fitz-Hugh-Curtis syndrome]

A case of Fitz-Hugh-Curtis syndrome (venereal perihepatitis) is reported. This syndrome is observed almost exclusively in women as a complication of genital gonococcal or chlamydial infections. A sudden, acute biliary-type pain generally characterizes the disease; only a few cases present symptoms related to associated genital infection. The real clinical incidence of venereal perihepatitis is quite high; in fact, a lot of the emergency admitted patients diagnosed with biliary colic or acute cholecystitis as a matter of fact suffer from this syndrome. If haematological investigations, ultrasonography and cholangiography do not confirm a suspected biliary lithiasis, it will be needed to investigate the genital tract. After clinical and ultrasound examinations, neisseria gonorrhoeae and chlamydia trachomatis must be sought in vaginal and cervical secretions and serum antichlamydial antibodies level is to be sought too. Through these examinations, the venereal perihepatitis can usually be diagnosed. In uncertain cases laparoscopy can be useful: in fact, it can reveal the typical violin-string-like adhesions between the anterior liver capsule and the anterior abdominal wall, and, in the same session, it allow to resect them. Tetracycline, doxycycline and, more recently, ofloxacine gave good results in the syndrome's treatment.

[Laparoscopic appendectomy]

The authors report their experience of 6 cases of appendicectomy using a laparoscopic route of which 5 were performed under local anesthesia and 1 under general anesthesia. The results indicate that this new technique is easy to perform and as rapid and safe as the traditional operation. The possibility of using local anesthesia, the lack of complications when operating on obese patients, the lower incidence of wound infections and rapid postoperative mobilisation all argue in favour of this alternative approach to conventional open surgery.

[Current etiopathogenic guides in pulmonary embolism]

Pulmonary embolism is still a dangerous postoperative complication in spite of antithrombotic prophylaxis. The paper examines the etiopathogenetic stages of the disease and stresses the relevance of Wircov's triad today, even in the light of recent acquisitions which highlight the role of endothelium as a modulator of the fibrinolytic process.

[Phyllodes tumors of the breast. Clinico-statistical data from the division of Obstetrics and Gynecology of the S. Giacomo Hospital for the years 1981-1985]

In the light of twenty cases encountered in only five years, the peculiar characteristics of cystosarcoma phyllodes of the breast are described, with an analysis of its morphological, diagnostic, therapeutic and prognostic aspects.