Revascularization with BYCROSS atherectomy device - protocol of a prospective multicenter observational study

Background The BYCROSS™ device is a novel device intended for use in atherectomy of the peripheral arterial disease (PAD). With the BYCROSS™ atherectomy system, also prolonged calcifying lesions can be treated in a minimally invasive manner, which was previously reserved for bypass surgery. The aim of this study is to collect additional clinical data on safety and performance of the BYCROSS™ from patients undergoing revascularization of severely stenotic or occluded peripheral arterial vessels with the BYCROSS™. Methods and design This is an investigator-initiated national prospective multicenter observational study in patients with PAD. Sixty patients (20 per center) with PAD with stenosis higher than 80% or complete occlusion (de novo or recurrent stenosis) of vessels below the aortic bifurcation (min 3 mm vessel diameter) will be recruited. Three vascular surgery centers are participating in the study. The primary efficacy endpoint is procedural success, defined as passage of the occlusion through the BYCROSS device, and safety outcomes, explicated as freedom from device-related serious adverse events (SADEs). Secondary endpoints include primary and secondary patency rates, change in Rutherford classification, and freedom from amputation at 3 and 12 months. Discussion The BYCROSS atherectomy system may be a novel device for the minimally invasive treatment of prolonged calcified lesions previously reserved for bypass surgery. This national prospective multicenter observational study could represent another step in demonstrating the efficancy and safety of this device for treatment of PAD

Artificial intelligence-based detection of pneumonia in chest radiographs

Artificial intelligence is gaining increasing relevance in the field of radiology. This study retrospectively evaluates how a commercially available deep learning algorithm can detect pneumonia in chest radiographs (CR) in emergency departments. The chest radiographs of 948 patients with dyspnea between 3 February and 8 May 2020, as well as 15 October and 15 December 2020, were used. A deep learning algorithm was used to identify opacifications associated with pneumonia, and the performance was evaluated by using ROC analysis, sensitivity, specificity, PPV and NPV. Two radiologists assessed all enrolled images for pulmonal infection patterns as the reference standard. If consolidations or opacifications were present, the radiologists classified the pulmonal findings regarding a possible COVID-19 infection because of the ongoing pandemic. The AUROC value of the deep learning algorithm reached 0.923 when detecting pneumonia in chest radiographs with a sensitivity of 95.4%, specificity of 66.0%, PPV of 80.2% and NPV of 90.8%. The detection of COVID-19 pneumonia in CR by radiologists was achieved with a sensitivity of 50.6% and a specificity of 73%. The deep learning algorithm proved to be an excellent tool for detecting pneumonia in chest radiographs. Thus, the assessment of suspicious chest radiographs can be purposefully supported, shortening the turnaround time for reporting relevant findings and aiding early triage

Visualization of bone details in a novel photon-counting dual-source CT scanner—comparison with energy-integrating CT

OBJECTIVES: Photon-counting detector CT (PCD-CT) promises a leap in spatial resolution due to smaller detector pixel sizes than implemented in energy-integrating detector CTs (EID-CT). Our objective was to compare the visualization of smallest bone details between PCD-CT and EID-CT using a mouse as a specimen. MATERIALS AND METHODS: Two euthanized mice were scanned at a 20-slice EID-CT and a dual-source PCD-CT in single-pixel mode at various CTDI(Vol) values. Image noise and signal-to-noise ratio (SNR) were evaluated using repeated ROI measurements. Edge sharpness of bones was compared by the maximal slope within CT value plots along sampling lines intersecting predefined bones of the spine. Two readers evaluated bone detail visualization at four regions of the spine on a three-point Likert scale at various CTDI(Vol)’s. Two radiologists selected the series with better detail visualization among each of 20 SNR-matched pairs of EID-CT and PCD-CT series. RESULTS: In CTDI(Vol)-matched scans, PCD-CT series showed significantly lower image noise (Noise(CTDI=5 mGy): 16.27 ± 1.39 vs. 23.46 ± 0.96 HU, p < 0.01), higher SNR (SNR(CTDI=5 mGy): 20.57 ± 1.89 vs. 14.00 ± 0.66, p < 0.01), and higher edge sharpness (Edge Slope(lumbar spine): 981 ± 160 vs. 608 ± 146 HU/mm, p < 0.01) than EID-CT series. Two radiologists considered the delineation of bone details as feasible at consistently lower CTDI(Vol) values at PCD-CT than at EID-CT. In comparison of SNR-matched reconstructions, PCD-CT series were still considered superior in almost all cases. CONCLUSIONS: In this head-to-head comparison, PCD-CT showed superior objective and subjective image quality characteristics over EID-CT for the delineation of tiniest bone details. Even in SNR-matched pairs (acquired at different CTDI(Vol)’s), PCD-CT was strongly preferred by radiologists. KEY POINTS: • In dose-matched scans, photon-counting detector CT series showed significantly less image noise, higher signal-to-noise ratio, and higher edge sharpness than energy-integrating detector CT series. • Human observers considered the delineation of tiny bone details as feasible at much lower dose levels in photon-counting detector CT than in energy-integrating detector CT. • In direct comparison of series matched for signal-to-noise ratio, photon-counting detector CT series were considered superior in almost all cases. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00330-021-08441-4

Acute abdomen—Rare cause in an 80-year-old female patient under immunosuppressive treatment

Eine 80-jährige Frau stellte sich zur Abklärung abdomineller Schmerzen vor. Vorausgegangen war die Diagnosestellung einer Autoimmunhepatitis mit Einleitung einer immunsuppressiven Therapie und Auftritt zweier Pneumonien mit opportunistischen Erregern. Die Bildgebung erbrachte einen „omental cake“ mit Verdacht auf Peritonealkarzinose. Bei Auftritt eines akuten Abdomens erfolgte eine explorative Laparotomie, hierbei zeigten sich intraabdominelle Abszesse. Anhand von Blutkulturen und des intraoperativ gewonnenen Materials wurde eine disseminierte Nocardiose diagnostiziert. Die Patientin verstarb aufgrund einer fulminant verlaufenen Sepsis

Optimal conspicuity of liver metastases in virtual monochromatic imaging reconstructions on a novel photon-counting detector CT—effect of keV settings and BMI

In dual-energy CT datasets, the conspicuity of liver metastases can be enhanced by virtual monoenergetic imaging (VMI) reconstructions at low keV levels. Our study investigated whether this effect can be reproduced in photon-counting detector CT (PCD-CT) datasets. We analyzed 100 patients with liver metastases who had undergone contrast-enhanced CT of the abdomen on a PCD-CT (n = 50) or energy-integrating detector CT (EID-CT, single-energy mode, n = 50). PCD-VMI-reconstructions were performed at various keV levels. Identical regions of interest were positioned in metastases, normal liver, and other defined locations assessing image noise, tumor-to-liver ratio (TLR), and contrast-to-noise ratio (CNR). Patients were compared inter-individually. Subgroup analyses were performed according to BMI. On the PCD-CT, noise and CNR peaked at the low end of the keV spectrum. In comparison with the EID-CT, PCD-VMI-reconstructions exhibited lower image noise (at 70 keV) but higher CNR (for ≤70 keV), despite similar CTDIs. Comparing high- and low-BMI patients, CTDI-upregulation was more modest for the PCD-CT but still resulted in similar noise levels and preserved CNR, unlike the EID-CT. In conclusion, PCD-CT VMIs in oncologic patients demonstrated reduced image noise–compared to a standard EID-CT–and improved conspicuity of hypovascularized liver metastases at low keV values. Patients with higher BMIs especially benefited from constant image noise and preservation of lesion conspicuity, despite a more moderate upregulation of CTDI

clinical long-term efficacy and factors influencing the outcome

Wie in Originalarbeit 1 an 15 Patientinnen prospektiv mittels kontrastmittelgestützter MRT demonstriert werden konnte, führt die bilaterale UAE regelhaft zu einer Ischämie sowohl der in die Gebärmutter eingebetteten Leiomyome als auch des Myometriums selbst. Dabei ist die Perfusionsrestriktion der Gebärmuttermuskulatur nur temporär und bildet sich innerhalb von 72 h nahezu vollständig zurück. Im Gegensatz dazu bleibt einmal ischämisches Myomgewebe avital und erholt sich nicht wieder, was entscheidend für den langfristigen Therapieerfolg ist. Dieser wurde im Rahmen zweier prospektiv angelegter Kohortenstudien (Originalarbeiten 2 und 3) mit 380 bzw. 82 eingeschlossenen Patientinnen untersucht. Etwa 3/4 aller Betroffenen profitierte dabei dauerhaft von der Behandlung und berichtete eine zufriedenstellende Verbesserung bzw. Rückbildung ihrer Blutungs- und Druckbeschwerden. Das mittlere reinterventionsfreie Überleben lag bei 8,5 Jahren, womit die Mehrzahl der Betroffenen beschwerdefrei in die natürlich einsetzende Menopause überführt werden kann. Konsekutiv zeigten Frauen, die zum Zeitpunkt der UAE <40 Jahre waren, ein gut doppelt so hohes Risiko für ein Therapieversagen wie Frauen >45 Jahre (P = 0,049). Ein verfrühtes Auftreten der Menopause konnte dabei nicht beobachtet werden. Die krankheitsspezifische Lebensqualität erfolgreich behandelter Frauen normalisierte sich bereits im kurzfristigen Verlauf (P < 0,001) und besserte sich noch einmal langfristig (P = 0,041), womit der therapeutische Nutzen auch über die Kontrolle der typischen Beschwerden hinaus demonstriert werden konnte. Dennoch profitieren langfristig ca. 1/4 der behandelten Frauen nicht von der Therapie und erleben eine Rückkehr der Beschwerden. In Originalarbeit 4 wurden potentielle Einflussfaktoren auf den klinischen Erfolg an 115 Patientinnen prospektiv untersucht, wobei die Rate der erreichten Myominfarzierung als der einzig relevante und dabei sehr zuverlässige Prädiktor für das therapeutische Ansprechen identifiziert wurde. So unterlagen Patientinnen, bei denen nur eine Infarzierung von <90 % der Myomlast erreicht werden konnte, einem 22,2-fach (P < 0,001) höheren Risiko für ein Therapieversagen als Frauen mit vollständiger Infarzierung. Langfristig bedeutete dies eine kumulative Reinterventionsrate von 43 % gegenüber 2 %. Besonders abhängig von einer hohen Infarzierungsrate schienen Frauen mit dominierenden Blutungsbeschwerden. Unter diesen lag das analoge Risiko 40,5-fach höher und die Reinterventionsrate erreichte bereits nach 4 Jahren 94 % gegenüber 13 % (P < 0,001). Um eine möglichst vollständige Infarzierung zu erreichen, genügt in seltenen Fällen die alleinige UAE nicht, da über geweitete Arteriae ovaricae eine relevante Myomversorgung vorliegen kann. Originalarbeit 5 zeigt retrospektiv an 13 Frauen, dass eine ergänzende OAE technisch einfach zu realisieren ist und effektiv zur Infarzierung der Myomlast und damit einhergehend der klinischen Symptomkontrolle beiträgt. Eine zufriedenstellende Beschwerdebesserung berichteten anschließend 92 % der Patientinnen. Ein erhöhtes Risiko für eine verfrühte permanente Amenorrhoe konnte dabei nicht beobachtet werden. Die UAE kann, wie in Originalarbeit 6 an 40 Patientinnen retrospektiv demonstriert, auch bei der Adenomyosis uteri erfolgreich eingesetzt werden. Dabei ist das klinische Ansprechen bei alleiniger Adenomyose jedoch schlechter als bei kombinierter Adenomyose und Leiomyomatose. Nach 6 Jahren liegt das kumulative reinterventionsfreie Überleben für Frauen mit reiner Adenomyose bei 48 %, bei begleitender, aber der Adenomyose untergeordneter Leiomyomatose bei vergleichbaren 58 %. Frauen mit dominierender Leiomyomatose erlebten kein Therapieversagen. Erfolgreich behandelte Frauen zeigten eine Normalisierung ihrer Lebensqualität. In Ermangelung alternativer organerhaltender Behandlungsoptionen sollten Patientinnen trotz des im Vergleich zum Uterus myomatosus schlechteren Langzeiterfolgs bzgl. der Möglichkeit einer UAE beraten werden.Publication 1 presents a prospective study of 15 women examined with contrast- enhanced magnetic resonance imaging (MRI). The study shows that bilateral uterine artery embolization (UAE) consistently causes ischemia of both fibroids embedded within the uterine wall and of the myometrium itself. However, while reduced blood flow to the muscle layer of the uterus is temporary and usually returns to near-normal within 72 hours, ischemic fibroid tissue remains nonviable and does not recover, which is crucial for the long- term success of UAE treatment. Long-term outcome of UAE was investigated in two prospective cohort studies (publications 2 and 3) including 380 and 82 patients. Approx. three quarters of the women treated benefited permanently from UAE and reported satisfactory improvement or resolution of bleeding problems and bulk-related symptoms. Mean survival without reintervention was 8.5 years, meaning that the majority of women experience relief of fibroid- related symptoms that is maintained to the time of natural menopause. Thus, women aged <40 years at the time of UAE had a slightly over two times higher risk of treatment failure than women aged >45 years (P = 0.049). Premature menopause was not observed. Disease-specific quality of life of successfully treated women already returned to normal during short-term follow-up (P < 0,001) and improved further at long-term follow-up (P = 0.041), suggesting that a therapeutic benefit of UAE goes beyond mere control of typical fibroid- related complaints. Nevertheless, approx. one quarter of women undergoing UAE have no long-term benefit and experience a recurrence of their symptoms. Publication 4 prospectively investigated factors potentially influencing the clinical success of UAE in 115 patients, identifying the rate of fibroid infarction as the only relevant and very reliable predictor of the response to treatment. Patients with infarction of <90 % of their fibroid load had a 22.2 times (P < 0.001) higher risk of treatment failure than women in whom complete infarction was accomplished. At long-term follow-up, this difference resulted in a cumulative reintervention rate of 43% versus 2%. The infarction rate accomplished appeared to be most relevant in women presenting with abnormal bleeding as the predominant fibroid-related complaint. In this subgroup, the risk of treatment failure was 40.5 times higher, and the reintervention rate at 4-year follow-up was 94% versus 13% (P < 0.001). In rare instances, complete infarction cannot be accomplished by UAE alone since dilated ovarian arteries may provide relevant fibroid blood supply. Publication 5 presents a retrospective analysis of 13 women, showing that supplementary OAE is technically easy to perform and effectively contributes to infarction of the fibroid bulk and elimination of clinical symptoms. Satisfactory improvement of symptoms was reported by 92% of the women with supplementary OAE. There was no risk for premature permanent amenorrhea. Publication 6, which reports a retrospective study of 40 patients, demonstrates that UAE is also successful in treating adenomyosis uteri. However, the clinical response is poorer in women with adenomyosis alone compared to women with combined adenomyosis and fibroids. At 6-year follow-up, cumulative reintervention-free survival was 48% in women with adenomyosis alone and only slightly better, 58%, in women with predominant adenomyosis and concomitant fibroids. There were no treatment failures when fibroids were the predominant condition. Successfully treated women experienced a return to normal of their quality of life. In view of the fact that there is no alternative uterus-sparing treatment option for women with adenomyosis uteri, these women should be informed and counseled about UAE although the long-term success is poorer than in women with uterine fibroids