Bridging the experience gap in prostate multiparametric magnetic resonance imaging using artificial intelligence: A prospective multi-reader comparison study on inter-reader agreement in PI-RADS v2.1, image quality and reporting time between novice and expert readers.

PURPOSE: The aim of the study was to determine the impact of using a semi-automatic commercially available AI-assisted software (Quantib® Prostate) on inter-reader agreement in PI-RADS scoring at different PI-QUAL ratings and grades of reader confidence and on reporting times among novice readers in multiparametric prostate MRI. METHODS: A prospective observational study, with a final cohort of 200 patients undergoing mpMRI scans, was performed at our institution. An expert fellowship-trained urogenital radiologist interpreted all 200 scans based on PI-RADS v2.1. The scans were divided into four equal batches of 50 patients. Four independent readers evaluated each batch with and without the use of AI-assisted software, blinded to expert and individual reports. Dedicated training sessions were held before and after each batch. Image quality rated according to PI-QUAL and reporting times were recorded. Readers' confidence was also evaluated. A final evaluation of the first batch was conducted at the end of the study to assess for any changes in performance. RESULTS: The overall kappa coefficient differences in PI-RADS scoring agreement without and with Quantib® were 0.673 to 0.736 for Reader 1, 0.628 to 0.483 for Reader 2, 0.603 to 0.292 for Reader 3 and 0.586 to 0.613 for Reader 4. Using PI-RADS ≥ 4 as cut-off for biopsy, the AUCs with AI ranged from 0.799 (95 % CI: 0.743, 0.856) to 0.820 (95 % CI: 0.765, 0.874). Inter-reader agreements at different PI-QUAL scores were higher with the use of Quantib, particularly for readers 1 and 4, with Kappa coefficient values showing moderate to slight agreement. CONCLUSION: Quantib® Prostate could potentially be useful in improving inter-reader agreement among less experienced to completely novice readers if used as a supplement to PACS.

Bi-unicompartmental and combined uni plus patellofemoral replacement: indications and surgical technique.

The anatomy and orientation of the condyles and the trochlea are not standard, but related to morphotype, gender and race. Consequently, the extreme variability in their dimension, and in the distance and angle between the axis of the condyles and of the trochlea, often necessitates a "custom-made" replacement. This may be achieved through the use of small implants. Bicompartmental osteoarthritis with intact ligaments should be addressed with bi-unicompartmental (bi-UKR) or UKR plus patellofemoral replacement (PFR). These options allow selective replacement of the worn compartments and a customised fit of the small implants to the native knee anatomy. Clinical consequences are restoration of the native knee kinematics and overall better function.

Validation of rate of perceived exertion-based exercise training in patients with heart failure: insights from autonomic nervous system adaptations.

BACKGROUND: Exercise prescription in cardiac patients is based on heart rate (HR) response to exercise. How to prescribe long-term exercise training outside medically-supervised settings also considering changes in individual physical capacity over time is unknown. In this study we hypothesized that in patients with chronic heart failure (CHF) the session-rate of perceived exertion (RPE), a subjective-based training methodology, provides autonomic and functional capacity changes superimposable to those observed with HR-based Training Impulses (TRIMPi) method. METHODS: Twenty patients with stable CHF were randomized to either aerobic continuous training (ACT) or aerobic interval training (AIT) for 12 weeks. For each TRIMPi-guided exercise session, the session-RPE was recorded. By this method, internal training load (TL) is quantified by multiplying the RPE of the whole training session, using the Borg CR10-scale, by its duration. Heart rate variability (HRV), and baroreflex sensitivity (BRS) were assessed at baseline and at 3 weeks intervals. RESULTS: Significant correlations were found between TRIMPi and individual session-RPE, for both ACT and AIT (r=0.63 to 0.81), (P<0.05). The same occurred when ACT and AIT groups were pooled together (r=0.72; P<0.01). R-R interval, HRV and BRS were significantly and very highly correlated with weekly RPE-session (r(2) ranged from 0.77 to 0.97; P<0.001). A significant relationship between session-RPE and performance at the 6MWT was also found. CONCLUSIONS: Session-RPE is an easy-to-use, inexpensive and valid method for exercise prescription and health maintenance, consistent with objective physiological indices of training, that could be used for long-term physical activity in patients with CHF.

Effect of High-Intensity interval training versus moderate continuous training on 24-h blood pressure profile and insulin resistance in patients with chronic heart failure.

In patients with chronic heart failure (CHF) blood pressure (BP) control, represents a relevant target of management. This study evaluated the effect of different intensities exercise training on 24-h ambulatory BP profile and insulin resistance in patients with CHF. Thirty-six CHF patients with left ventricular ejection fraction <40%, were randomized to high-intensity interval training (HIT) or moderate continuous training (MIT) for 12 weeks. HIT consisted in treadmill exercise at ~75-80% of heart rate reserve (HRR), alternated with active pauses at 45-50% of HRR. MIT consisted in continuous treadmill at ~45-60% of HRR. Peak VO2 and anaerobic threshold increased significantly with both HIT and MIT, without significant differences between the two training programs. 24-h, systolic and diastolic BP decreased with both HIT and MIT. The same occurred for day-time and night-time systolic and diastolic BP. The decrease in day-time diastolic BP was slightly but significantly greater in HIT. Both HIT and MIT induced a significant decrease in fasting glucose and insulin, whereas HOMA-IR decreased significantly only after HIT. In patients with CHF exercise training reduces BP throughout the day, without substantial differences between moderate and more vigorous exercise intensity, with a small exception for day-time diastolic BP. HIT was more effective in improving insulin resistance.

Dose-response relationship of baroreflex sensitivity and heart rate variability to individually-tailored exercise training in patients with heart failure.

BACKGROUND: Heart Rate Variability (HRV) and Baroreflex Sensitivity (BRS) are impaired in patients with Chronic Heart Failure (CHF) and carry negative prognosis. Exercise training improves these parameters. However, the relationship between exercise training with HRV and BRS has been investigated without regard for individual training loads. We tested the hypothesis that in CHF patients changes in HRV and BRS are dose-response related to individual volume/intensity training load (TL). METHODS: Twenty patients with stable postinfarction CHF under optimal medical treatment were randomized to either aerobic continuous training (ACT) or aerobic interval training (AIT) for 12weeks. Individualized TL was monitored by the Training Impulses (TRIMPi) method, which was determined using the individual HR and lactate profiling determined during a treadmill test at baseline. HRV (standard deviation of mean R-R interval) and BRS were assessed at rest and 3weeks apart, throughout the study. RESULTS: HRV, BRS and R-R interval increased significantly with training, being very highly correlated to the dose of exercise with a second-order regression model (r(2) ranged from 0.75 to 0.96; P<0.001), resembling a bell-shaped in the ACT, and an asymptotic-shaped curve in the AIT groups, respectively. These changes were accompanied by a significant increase in functional capacity. No significant differences were detected between ACT and AIT in any variable. CONCLUSIONS: These results suggest that improvements in HRV and BRS by exercise training in CHF patients are dose related to TL in a non-linear fashion on an individual basis, with optimal results at moderate doses of exercise.

Matched dose interval and continuous exercise training induce similar cardiorespiratory and metabolic adaptations in patients with heart failure.

BACKGROUND: The best format of exercise training in patients with chronic heart failure (CHF) is controversial. We tested the hypothesis that aerobic continuous training (ACT) and aerobic interval training (AIT) induce similar effects on functional capacity, central hemodynamics and metabolic profile in patients with postinfarction CHF provided that the training load is equated by an individually-tailored volume/intensity dose of exercise. METHODS: Twenty patients with postinfarction CHF under optimal medical treatment were randomized to ACT or AIT for 12 weeks. Exercise training consisted in individualized loads prescribed according to the Training Impulses (TRIMPi) method, which was determined using the individual HR and lactate profiling obtained during a treadmill test at baseline. RESULTS: Peak VO2 increased significantly by 22% with both ACT and AIT, without differences between the two training programs. Changes in anaerobic threshold and VE/VCO2 slope were not significantly different between ACT and AIT. Resting HR significantly decreased with both exercise modes. Resting cardiac output and stroke volume, left ventricular diastolic dimension and ejection fraction did not change from baseline with both exercise modes. Lipid profile and glucose metabolism were not substantially altered by ACT and AIT. CONCLUSIONS: ACT and AIT both induce significant improvement in aerobic capacity in patients with postinfarction CHF, without significant differences between the two training modes, provided that patients are trained at the same, individually tailored, dose of exercise. The TRIMPi method might represent a step forward in the individualization of an aerobic training tailored to the patient's clinical and functional status within cardiac rehabilitation programs.

Baroreflex and metaboreflex control of cardiovascular system during exercise in space.

This brief review summarizes current knowledge on the neural mechanisms of cardiovascular regulation during exercise in space, with specific emphasis on the role of the arterial baroreflex and the muscle metaboreflex, with the attendant modifications in autonomic nervous system activity, in determining the cardiovascular responses to exercise in microgravity conditions. Available data suggest that the muscle metaboreflex is enhanced during dynamic exercise in space and that the potentiation of the muscle metaboreflex affects the vagally mediated arterial baroreflex contribution to HR control.

Dose-response relationship of autonomic nervous system responses to individualized training impulse in marathon runners.

In athletes, exercise training induces autonomic nervous system (ANS) adaptations that could be used to monitor training status. However, the relationship between training and ANS in athletes has been investigated without regard for individual training loads. We tested the hypothesis that in long-distance athletes, changes in ANS parameters are dose-response related to individual volume/intensity training load and could predict athletic performance. A spectral analysis of heart rate (HR), systolic arterial pressure variability, and baroreflex sensitivity by the sequences technique was investigated in eight recreational athletes during a 6-mo training period culminating with a marathon. Individualized training load responses were monitored by a modified training impulse (TRIMP(i)) method, which was determined in each athlete using the individual HR and lactate profiling determined during a treadmill test. Monthly TRIMP(i) steadily increased during the training period. All the ANS parameters were significantly and very highly correlated to the dose of exercise with a second-order regression model (r(2) ranged from 0.90 to 0.99; P < 0.001). Variance, high-frequency oscillations of HR variability (HRV), and baroreflex sensitivity resembled a bell-shaped curve with a minimum at the highest TRIMP(i), whereas low-frequency oscillations of HR and systolic arterial pressure variability and the low frequency (LF)-to-high frequency ratio resembled an U-shaped curve with a maximum at the highest TRIMP(i). The LF component of HRV assessed at the last recording session was significantly and inversely correlated to the time needed to complete the nearing marathon. These results suggest that in recreational athletes, ANS adaptations to exercise training are dose related on an individual basis, showing a progressive shift toward a sympathetic predominance, and that LF oscillations in HRV at peak training load could predict athletic achievement in this athlete population.

Effects of residential exercise training on heart rate recovery in coronary artery patients.

The aims of the present study are twofold: 1) to investigate whether heart rate recovery (HRR) after a cycle ergometry test is affected by exercise training and 2) to test the ability of HRR to replicate the baroreflex sensitivity (BRS) changes that occur in response to an exercise training program in coronary artery patients. We randomized 82 coronary artery patients undergoing a residential cardiac rehabilitation program to an exercise training group (TR; n = 43) and an untrained group (UTR; n = 39). All of the patients underwent an exercise test before and after the rehabilitation program. HRR was recorded at the end of the 1st and 2nd min after exercise. BRS was determined at rest before and after treatment. HRR after the 2nd min was significantly improved in TR patients (-21.4 +/- 0.9 beats/min) compared with UTR patients (-17.8 +/- 1.2 beats/min) at the end of the training program. Improvement in HRR paralleled that in BRS in TR patients (from 3.2 +/- 0.3 to 5.3 +/- 0.8 ms/mmHg; P < 0.001), whereas no significant change was evident in UTR patients (from 3.5 +/- 0 to 4.0 +/- 0.4 ms/mmHg; P = 0.230). Our data show that HRR in the 2nd min after the cessation of a cycle ergometer exercise test increased in coronary artery patients after an exercise training period. This result confirms the positive effect induced by exercise training on HRR and extends the conclusions of previous studies to different modalities of exercise (i.e., cycle ergometer). HRR might provide an additional simple marker of the effectiveness of physical training programs in cardiac patients.

Baroreflex buffering of sympathetic activation during sleep: evidence from autonomic assessment of sleep macroarchitecture and microarchitecture.

We examined the effects of sleep microstructure, ie, the cyclic alternating pattern (CAP), on heart rate (HR)- and blood pressure (BP)-regulating mechanisms and on baroreflex control of HR in healthy humans and tested the hypothesis that sympathetic activation occurring in CAP epochs during non-rapid eye movement (non-REM) sleep periods is buffered by the arterial baroreflex. Ten healthy males underwent polysomnography and simultaneous recording of BP, ECG, and respiration. Baroreflex sensitivity (BRS) was calculated by the sequences method. Autoregressive power spectral analysis was used to investigate R-R interval (RRI) and BP variabilities. During overall non-REM sleep, BP decreased and RRI increased in comparison to wakefulness, with concomitant decreases in low-frequency RRI and BP oscillations and increases in high-frequency RRI oscillations. These changes were reversed during REM to wakefulness levels, with the exception of RRI. During CAP, BP increased significantly in comparison to non-CAP and did not differ from REM and wakefulness. The low-frequency component of BP variability was significantly higher during CAP than non-CAP. RRI and its low-frequency spectral component did not differ between CAP and non-CAP. BRS significantly increased during CAP in comparison to non-CAP. BRS was not different during CAP and REM and was greater during both in comparison with the awake state. Even during sleep stages, like non-REM sleep, characterized by an overall vagal predominance, phases of sustained sympathetic activation do occur that resemble that occurring during REM. Throughout the overnight sleep period, the arterial baroreflex acts to buffer surges of sympathetic activation by means of rapid changes in cardiac vagal circuits.

Sleep-related changes in baroreflex sensitivity and cardiovascular autonomic modulation.

OBJECTIVE: We examined the effects of the various sleep stages on baroreflex sensitivity (BRS), and heart rate and blood pressure (BP) variability, and tested the hypothesis that there is a different behavior of the baroreflex control of the sinus node in response to hypertensive and hypotensive stimuli and in relation to different cycles of the overnight sleep. DESIGN: Polygraphic sleep recordings were performed in 10 healthy males. The BP and the RR interval were continuously recorded during sleep. METHODS: BRS was calculated by the sequences method. Autoregressive power spectral analysis was used to investigate the RR-interval and BP variabilities. RESULTS: During rapid eye movement (REM) sleep BRS significantly increased in response to hypertensive stimuli in comparison with non-rapid eye movement (NREM) sleep and the awake state, whereas it did not change in response to hypotensive stimuli. In the first sleep cycle, BRS significantly increased during NREM in comparison with wakefulness, whereas during REM BRS in response to hypertensive stimuli did not show significant changes as compared with the awake state and/or with NREM. During REM occurring in the sleep cycle before morning awakening, BRS showed a significant increase in response to hypertensive stimuli in comparison with both NREM and the awake state. CONCLUSIONS: During sleep, arterial baroreflex modulation of the sinus node is different in response to hypotensive and hypertensive stimuli particularly during REM. Furthermore, baroreflex control of the sinus node shows a non-uniform behavior during REM occurring in different nocturnal sleep cycles. These findings suggest that the arterial baroreflex is more effective in buffering the increased sympathetic activation associated with REM at the end of sleep than in the early night.

Hemodynamic and autonomic correlates of postexercise hypotension in patients with mild hypertension.

We investigated the interplay of neural and hemodynamic mechanisms in postexercise hypotension (PEH) in hypertension. In 15 middle-aged patients with mild essential hypertension, we evaluated blood pressure (BP), cardiac output (CO), total peripheral resistance (TPR), forearm (FVR) and calf vascular resistance (CVR), and autonomic function [by spectral analysis of R-R interval and BP variabilities and spontaneous baroreflex sensitivity (BRS)] before and after maximal exercise. Systolic and diastolic BP, TPR, and CVR were significantly reduced from baseline 60-90 min after exercise. CO, FVR, and HR were unchanged. The low-frequency (LF) component of BP variability increased significantly after exercise, whereas the LF component of R-R interval variability was unchanged. The overall change in BRS was not significant after exercise vs. baseline, although a significant, albeit small, BRS increase occurred in response to hypotensive stimuli. These findings indicate that in hypertensive patients, PEH is mediated mainly by a peripheral vasodilation, which may involve metabolic factors linked to postexercise hyperemia in the active limbs. The vasodilator effect appears to override a concomitant, reflex sympathetic activation selectively directed to the vasculature, possibly aimed to counter excessive BP decreases. The cardiac component of arterial baroreflex is reset during PEH, although the baroreflex mechanisms controlling heart period appear to retain the potential for greater opposition to hypotensive stimuli.