AI-support for the detection of intracranial large vessel occlusions: One-year prospective evaluation.

Purpose: Few studies have evaluated real-world performance of radiological AI-tools in clinical practice. Over one-year, we prospectively evaluated the use of AI software to support the detection of intracranial large vessel occlusions (LVO) on CT angiography (CTA). Method: Quantitative measures (user log-in attempts, AI standalone performance) and qualitative data (user surveys) were reviewed by a key-user group at three timepoints. A total of 491 CTA studies of 460 patients were included for analysis. Results: The overall accuracy of the AI-tool for LVO detection and localization was 87.6%, sensitivity 69.1% and specificity 91.2%. Out of 81 LVOs, 31 of 34 (91%) M1 occlusions were detected correctly, 19 of 38 (50%) M2 occlusions, and 6 of 9 (67%) ICA occlusions. The product was considered user-friendly. The diagnostic confidence of the users for LVO detection remained the same over the year. The last measured net promotor score was -56%. The use of the AI-tool fluctuated over the year with a declining trend. Conclusions: Our pragmatic approach of evaluating the AI-tool used in clinical practice, helped us to monitor the usage, to estimate the perceived added value by the users of the AI-tool, and to make an informed decision about the continuation of the use of the AI-tool.

Reasons for (non)participation in supplemental population-based MRI breast screening for women with extremely dense breasts.

AIM: To determine the willingness of women with extremely dense breasts to undergo breast cancer screening with magnetic resonance imaging (MRI) in a research setting, and to examine reasons for women to participate or not. MATERIALS AND METHODS: Between 2011 and 2015, 8,061 women (50-75 years) were invited for supplemental MRI as part of the Dense Tissue and Early Breast Neoplasm Screening (DENSE) trial (ClinicalTrials.gov Identifier: NCT01315015), after a negative screening mammography in the national population-based mammography screening programme. Demographics of participants and non-participants were compared. All invitees were asked to report reasons for (non)participation. Ethical approval was obtained. Participants provided written informed consent. RESULTS: Of the 8,061 invitees, 66% answered that they were interested, and 59% eventually participated. Participants were on average 54-years old (interquartile range: 51-59 years), comparable to women with extremely dense breasts in the population-based screening programme (55 years). Women with higher socio-economic status (SES) were more often interested in participation than women with lower SES (68% versus 59%, p<0.001). The most frequently stated reasons for non-participation were "MRI-related inconveniences and/or self-reported contraindications to MRI" (27%) and "anxiety regarding the result of supplemental screening" (21%). "Expected personal health benefit" (68%) and "contribution to science" (43%) were the most frequent reasons for participation. CONCLUSION: Of women invited for MRI because of extremely dense breasts, 59% participated. Common reasons for non-participation were "MRI-related inconveniences" and "anxiety regarding the result of supplemental screening". In case of future implementation, availability of precise evidence on benefits and harms might reduce this anxiety.

[Dual-energy CT: new diagnostic possibilities]. / 'Dual-energy CT': nieuwe diagnostische mogelijkheden.

Dual-energy CT (DECT) provides more information than a conventional CT scan. This new technique does not only provide morphological information, but also provides information about the chemical composition of tissues and substances, e.g. uric acid or calcium, based on material-specific differences in X-ray attenuation, leading to diagnostic improvement. Other benefits include reduced radiation dose, reduced use of contrast fluids due to better iodine detection and improved image quality. DECT fulfils a need in patients with a hypersensitivity to contrast agents, leads to less kidney damage, and avoids the necessity of more invasive diagnostic methods such as lumbar punctures. There are clinical applications in the fields of cardiovascular and pulmonary medicine, urology and musculoskeletal diagnostics. For example, DECT can display monosodium urate depositions in a non-invasive manner, so that the effectiveness of gout treatment can be monitored. Kidney stones, coronary plaques and pulmonary emboli can also be displayed on the basis of their material-specific X-ray attenuation.

[Characterisation of breast lesions with VTIQ elastography: a new elastography method to evaluate the stiffness of tissues]. / Mammatumoren karakteriseren met VTIQ-elastografie.

B-mode ultrasound is used as an adjunct to mammography to differentiate between benign and malignant breast lesions. An additional ultrasound technique is elastography which can evaluate the stiffness of tissues. It is believed that malignant lesions are generally stiffer than benign lesions. Virtual touch tissue Quantification (VTIQ) is a new elastography method for measuring the stiffness of tissue. Because this method does not depend on the degree of compression, measurements are reliable and reproducible. VTIQ - in combination with ultrasonography - has the potential to characterise abnormalities in more detail. Adding elastography to regular B-mode ultrasound improves the diagnostic specificity without loss of sensitivity. This suggests that VTIQ might change patient management and avoid unnecessary biopsies. However, further research involving a greater variety of abnormalities and larger study populations is indicated.

Feasibility of a low concentration test bolus in CT angiography.

AIM: To investigate the feasibility of using a low-concentration test bolus in abdominal aorta computed tomography (CT) angiography (CTA). MATERIALS AND METHODS: In 10 patients referred for CTA of the abdominal aorta with a body mass index (BMI) ≤28 kg/m2, a standard test bolus of 10 ml contrast medium (CM; 350 mg iodine/ml) was compared with a low-concentration test bolus (5 ml CM; 350 mg iodine/ml; 1:1 diluted with saline) in terms of time to peak enhancement (tPE) and peak enhancement (PE). RESULTS: No significant differences were found between the standard and low-concentration test bolus in terms of tPE and PE. CONCLUSIONS: A low-concentration test bolus (5 ml, 1:1 diluted with saline) is feasible in patients with a BMI ≤28 kg/m2.

Reducing contrast medium volume and tube voltage in CT angiography of the pulmonary artery.

AIM: To evaluate image quality after contrast medium (CM) and tube voltage reduction in computed tomography angiography (CTA) of the pulmonary artery. MATERIALS AND METHODS: Thirty-three patients referred for CTA of the pulmonary artery for suspected pulmonary embolism were included. Patients were randomly assigned to Protocol I (100 ml of 350 mg iodine/ml iodinated CM; n=16) or Protocol II (50 ml of 350 mg iodine/ml iodinated CM; n=17). Dual-energy CT (80 kV and 140 kV) was performed in all patients. An averaged weighted series equivalent to a 120 kV image acquisition was reconstructed. The mean attenuation value of CM was measured at eight positions in the pulmonary trunk and pulmonary arteries. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Qualitative assessment of the vascular enhancement was performed independently by two experienced radiologists using a three-point scale. Mean attenuation values, image noise, CNR, and SNR of images with 50 ml CM and images with 100 ml CM were compared and mean attenuation values, image noise, CNR, and SNR in 80 kV images and 120 kV images were compared. For qualitative analysis, interobserver variability was analysed using Cohen's kappa statistics. RESULTS: The mean attenuation values in Protocol I and Protocol II were not significantly different at 80 kV (634.6±168.3 versus 537.9±146.7 HU; p=0.088) and 120 kV (482.8±127.7 versus 410.4±106.0 HU; p=0.085). The mean attenuation value at 80 kV was significantly higher than the mean attenuation value at 120 kV in Protocols I and II (p<0.001). The CNR and SNR were higher at 120 kV than at 80 kV in both protocols (p=0.000-0.019); however, there were no significant differences in the CNR and SNR between both protocols (p=0.600-0.952). Qualitative (subjective) analysis showed no statistical significant difference between Protocols I and II (p=0.524-1.000). CONCLUSION: Low tube voltage (80 kV) CTA using 50 ml CM is not inferior to CTA at 120 kV using 100 ml CM.

A non-invasive cardiac output measurement as an alternative to the test bolus technique during CT angiography.

AIM: To investigate the association between a non-invasive cardiac output (CO) measurement and the scan delay, as derived from a test bolus injection protocol. The secondary objective was to determine which factors affect the relationship between the CO and scan delay. MATERIALS AND METHODS: Fifty-five patients referred for a contrast-enhanced (thorax-)abdomen CT examination were included in this feasibility study. A test bolus examination was performed prior to the abdominal CT. During the test bolus injection, the CO of the patient was measured using a non-invasive finger-cuff measurement. Associations were analysed using linear regression analyses. Age, gender, height, weight, and blood pressure were included as potential confounders. RESULTS: Linear regression analysis showed a negative and significant association between CO and delay. The regression formula was as follows: scan delay (seconds) = 26.8-1.6 CO (l/min), with a 95% CI between -2.3 and -1.0 (p<0.001). Weight appeared to be a confounder in this relation, and gender and blood pressure were effect modifiers. There was no interaction between scan delay and age, height and weight. CONCLUSIONS: There is a negative and significant association between the non-invasive CO measurement and the CT scan delay; however, to validate these findings a larger cohort study is needed to investigate whether the non-invasively determined scan delay is as accurate as the use of a test bolus.

Low-dose CT angiography of the abdominal aorta and reduced contrast medium volume: Assessment of image quality and radiation dose.

AIM: To determine the effect of using 80 kV tube voltage and a reduced amount of contrast medium on the image quality and radiation dose of computed tomography angiography (CTA) of the abdominal aorta. MATERIALS AND METHODS: Patients who were referred for a CTA examination of the abdominal aorta were included in this technical efficacy study. Thirty patients were divided randomly into two groups. Fifteen patients underwent a dual-energy CT (DECT) protocol (Group A). Fifteen patients were scanned with the use of an automated tube potential selection algorithm tool (Group B). In both protocols, a test bolus injection of 10 ml ioversol (350 mg iodine/ml) was used, followed by 20 ml of 1:1 saline-diluted contrast medium. Quantitative analysis comprised determination of the mean attenuation and contrast-to-noise ratio. Qualitative image analysis was performed independently by five radiologists. The estimated radiation dose in terms of CT dose index and effective dose was recorded and compared with a standard 120 kV protocol. RESULTS: In Group B, six patients underwent CTA at 80 kV, seven patients underwent CTA at 100 kV and two patients underwent CTA at 120 kV. The mean contrast-enhancement values of Group A (80 kV) and the 80 kV subgroup of Group B were 16.5% and 27.6% higher compared to the 100 kV subgroup of Group B, these differences were, however, not significant. There were no significant differences in mean image quality between groups. In patients undergoing CTA at 80 kV the effective dose decreased by up to 51.3% compared to a conventional 120 kV CTA protocol. CONCLUSIONS: The findings of this study support the hypothesis that 80 kV in CTA of the abdominal aorta can reliably be used with only 30 ml contrast medium in total and a 50% reduction in radiation dose. The overall image quality was diagnostically adequate; however, it appeared to be suboptimal in patients with a BMI above 28 kg/m(2).

Ultrasound-guided radiofrequency ablation of early breast cancer in a resection specimen: lessons for further research.

PURPOSE: To assess the feasibility and effectiveness of radiofrequency ablation (RFA) in breast cancer, using different histopathologic staining methods to evaluate tissue viability. MATERIALS AND METHODS: In twenty patients with unifocal small (≤1, 5 cm) invasive ductal carcinoma, ultrasound-guided RFA was performed immediately after surgery. Cell viability was assessed using cytokeratin 8 (CK 8) and nicotinamide adenine dinucleotide diaphorase (NADHD) in addition to hematoxylin-eosin (HE). RESULTS: At histopathological examination, ex vivo RFA resulted in complete cell death of the target lesion in 17/20 patients. In two cases viable ductal carcinoma in situ (DCIS) was found just outside the completely ablated lesion. CONCLUSION: RFA of small invasive breast cancer seems to be a feasible treatment option. Both NADHD and CK 8 demonstrate a clear and comparable demarcation between viable and non-viable tissue. A high level of accuracy is required in proper positioning of the needle electrode and a "hot retraction" is mandatory.

Use of cytokeratin 8 immunohistochemistry for assessing cell death after radiofrequency ablation of breast cancers.

The effects of minimally invasive therapies such as radiofrequency ablation (RFA) and laser induced thermal therapy on breast carcinoma lesions usually is assessed by NADH diaphorase enzyme histochemistry for cell viability. NADH staining requires frozen material, however, with its associated poor morphology. We aimed to validate cytokeratin 8 (CK 8) immunohistochemistry as an alternative that works on paraffin sections. RFA was performed ex vivo on 20 breast resections after surgery and in vivo in eight patients who underwent general anesthesia followed by immediate resection. After treatment, specimens were lamellated and the tumors were divided into two equal parts. One part was fixed in neutral buffered formaldehyde for routine histopathological evaluation using hematoxylin and eosin (H & E) staining and CK 8 immunostaining. The other section was snap frozen and stored at -80° C for staining with NADH diaphorase. Both NADH diaphorase and CK 8 immunostaining demonstrated a clear and comparable demarcation between viable and nonviable tissues. The morphology of the CK 8 immunostained slides was much better, and fatty tissues could be judged readily by contrast to the NADH stained frozen sections, which had poor morphology and whose fatty parts were difficult to interpret. CK 8 immunohistochemistry seems to be well suited for assessing cell viability in breast tissue and for assessing the effects of RFA for breast cancer treatment. Because it can be applied to paraffin fixed material, it provides much better morphology than NADH staining and also can be applied to fatty tissues that usually are difficult to work up for frozen sections. Therefore, CK 8 immunohistochemistry may be preferred over NADH diaphorase staining for daily pathology practice for assessing the viability of breast carcinoma cells after RFA treatment.

[Radio frequency ablation therapy in the elderly breast cancer patient]. / Radiofrequente ablatiebehandeling van de oudere patiënte met een mammacarcinoom.

Breast cancer is an important health care problem, especially in the increasing elderly generation. Treatment of these fragile patients is a challenge for the clinician. Undertreatment has been linked to a higher percentage of recurrence and cancer related morbidity, while overtreatment leads to treatment related morbidity and mortality. Minimally invasive techniques do offer new opportunities for patients, who are no candidates for conventional surgery. The tumor lesion is treated locally and selective with minimal damage to surrounding tissue, yielding an adequate local tumor control. Radio frequency ablation technique seems an effective and safe method for treatment of the elderly patient with small (< 3 cm) breast cancer.

The value of sentinel lymph node biopsy in ductal carcinoma in situ (DCIS) and DCIS with microinvasion of the breast.

AIM: Ductal carcinoma in situ (DCIS) refers to the preinvasive stage of breast carcinoma and should not give axillary metastases. Its diagnosis, however, is subject to sampling errors. The role of sentinel lymph node biopsy (SLNB) in management of DCIS or DCISM (with microinvasion) remains unclear. The purpose of this study was to review our experience with SLNB in DCIS and DCISM. METHODS: A review of 51 patients with a diagnosis of DCIS (n=45) or DCISM (n=6), who underwent SLNB and a definitive breast operation between January 1999 and December 2006, was performed. RESULTS: In 10 patients (19.6%) definitive histology revealed an invasive carcinoma. SLN (micro)metastases were detected in 5 out of 51 patients, of whom 2 had a preoperative diagnosis of grade III DCIS and 3 of DCISM. Three patients (75%) had micrometastases (< 2 mm) only. In 2 patients, histopathology demonstrated a macrometastasis (> 2 mm). All 5 patients underwent axillary dissection. No additional positive axillary lymph nodes were found. CONCLUSIONS: In case of a preoperative diagnosis of grade III DCIS or a grade II DCIS with comedo necrosis and DCIS with microinvasion, an SLNB procedure has to be considered because in almost 20% of the patients an invasive carcinoma is found after surgery. In this case the SLNB procedure becomes less reliable after a lumpectomy or ablation has been performed. SLN (micro)metastases were detected in nearly 10% of the patients. The prognostic significance of individual tumour cells remains unclear.

The benefit of STent placement and blood pressure and lipid-lowering for the prevention of progression of renal dysfunction caused by Atherosclerotic ostial stenosis of the Renal artery. The STAR-study: rationale and study design.

BACKGROUND: Atherosclerotic renal artery stenosis (ARAS) is associated with progressive loss of renal function and is one of the most important causes of renal failure in the elderly. Current treatment includes restoration of the renal arterial lumen by endovascular stent placement. However, this treatment only affects damage caused by ARAS due to the stenosis and ensuing post-stenotic ischemia. ARAS patients have severe general vascular disease. Atherosclerosis and hypertension can also damage the kidney parenchyma causing renal failure. Medical treatment focuses on the latter. Lipid-lowering drugs (statins) could reduce renal failure progression and could reduce the overall high cardiovascular risk. The additional effect on preserving renal function of stent placement as compared to medical therapy alone is unknown. Therefore, the STAR-study aims to compare the effects of renal artery stent placement together with medication vs. medication alone on renal function in ARAS patients. METHOD: Patients with an ARAS of > or = 50% and renal failure (creatinine (Cr) clearance < 80 mL/min/1.73 m2) are randomly assigned to stent placement with medication or to medication alone. Medication consists of statins, anti-hypertensive drugs and antiplatelet therapy. Patients are followed for 2 yrs with extended follow-up to 5 yrs. The primary outcome of this study is a reduction in Cr clearance > 20% compared to baseline. This trial will include 140 patients.