CT-guided percutaneous biopsy of suspect pancreatic lesions: radiological and clinical outcome.

AIM: To evaluate the clinical utility of computed tomography (CT)-guided percutaneous biopsies of suspect pancreatic lesions regarding safety, efficiency, radiation dose, intervention time, diagnostic yield, and complications. MATERIALS AND METHODS: Between 2015 and 2018, 48 patients (18 female, 30 male; mean age: 64.2 years) with suspect pancreatic lesions underwent CT-guided percutaneous biopsy. Ultrasound-guided biopsy of all lesions was not possible or without any result. CT-guided interventions were compared according to the following intervention parameters: radiation dose, procedure duration, number of needle correction scans. Evaluation criteria included technical success as well as major and minor complications according to the Society of Interventional Radiology. RESULTS: Biopsies were performed successfully in 100% of patients. No major side effects occurred during intervention. As a minor complication, 29.2% showed focal haemorrhage. Seventy-seven percent of lesions had a malignant appearance, and benign inflammatory lesions were found in 23%. The mean size of the target lesions was 2.9 cm (range: 0.7-2.3 cm). The mean target access path within the patient was 8 cm (range: 3-14 cm). The duration to completion was 12 minutes (range: 3 minutes 30 seconds to 30 minutes). The dose-length product of the intervention was 89.5 mGy·cm (range: 11-350 mGy·cm). The average number needle correction scans was 31.1 (range: 6-36). CONCLUSION: CT-guided biopsy of suspect pancreatic lesions is an efficient and safe method. It can be performed within short intervention times and low radiation exposure for differentiation of unclear lesions.

CT-guided hook-wire localisation prior to video-assisted thoracoscopic surgery of pulmonary lesions.

AIM: To assess the feasibility, safety, and efficacy of computed tomography (CT)-guided pulmonary nodule localisation using a hooked guide wire before video-assisted thoracoscopic surgery (VATS). MATERIALS AND METHODS: The study included 79 patients with a history of malignancies outside the lung associated with pulmonary nodules. Mean lesion size was 0.7 cm (range 0.5-1.8 cm) and the mean lesion distance to the pleural surface was 1.5 cm (range 0.2-5 cm). All lesions (n=82) were marked with a 22-G hook wire. The technique was designed to insert the tip of the hook wire within or maximally 1 cm from the edge of the lesion. The Mann-Whitney U-test was used for univariate analyses and Fisher's exact test for categorical values. RESULTS: The hooked guide wire was positioned successfully in all 82 pulmonary nodules within mean time of 9 minutes (8-20 minutes, SD: 2.5 minutes). The procedure time was inversely proportional to the size of the lesion (Spearman correlation factor 0.7). Minimal pneumothoraces were observed in five patients (7.6%). Pneumothorax was not correlated to the histopathology of the pulmonary nodules (p>0.09). Focal perilesional pulmonary haemorrhage developed in four patients (5%). Both haemorrhage and pneumothorax were significantly correlated to lesions <10 mm (p=0.02 and 0.01 respectively). The volume of resected lung tissue was significantly correlated to lesions of increased distance from the pleural surface ≥2.5 cm in comparison to lesions of <2.5 cm from the pleural surface. CONCLUSION: CT-guided pulmonary nodule localisation prior to VATS could enable safe, accurate surgical guidance for the localisation of small pulmonary nodules.

Benefits of sinogram-affirmed iterative reconstruction in 0.4 mSv ultra-low-dose CT of the upper abdomen following transarterial chemoembolisation: comparison to low-dose and standard-dose CT and filtered back projection technique.

AIM: To evaluate the advantage of sinogram-affirmed iterative reconstruction (SIR) compared to filtered back projection (FBP) in upper abdomen computed tomography (CT) after transarterial chemoembolisation (TACE) at different tube currents. MATERIALS AND METHODS: The study was approved by the institutional review board. Written informed consent was obtained from all patients. Post-TACE CT was performed with different tube currents successively varied in four steps (180, 90, 45 and 23 mAs) with 40 patients per group (mean age: 60±12 years, range: 23-85 years, sex: 70 female, 90 male). The data were reconstructed with standard FBP and five different SIR strengths. Image quality was independently rated by two readers on a five-point scale. High (Lipiodol-to-liver) as well as low (liver-to-fat) contrast-to-noise ratios (CNRs) were intra-individually compared within one dose to determine the optimal strength (S1-S5) and inter-individually between different doses to determine the possibility of dose reduction using the Kruskal-Wallis test. RESULTS: Subjective image quality and objective CNR analysis were concordant: intra-individually, SIR was significantly (p<0.001) superior to FBP. Inter-individually, regarding different doses (180 versus 23 ref mAs), there was no significant (p=1.00) difference when using S5 SIR at 23 mAs instead of FBP. CONCLUSION: SIR allows for an 88% dose reduction from 3.43 to 0.4 mSv in unenhanced CT of the liver following TACE without subjective or objective loss in image quality.

Evaluation of image quality and dose reduction of 80 kVp neck computed tomography in patients with suspected peritonsillar abscess.

AIM: To evaluate neck computed tomography (CT) with a reduced tube voltage of 80 kVp in patients with suspected peritonsillar abscess (PTA) regarding objective and subjective image quality, and the potential for dose reduction. MATERIALS AND METHODS: Forty-seven patients with clinically suspected PTA were retrospectively analysed. Patients were examined using dual-source CT in dual-energy mode. The objective and subjective image quality of 80 kVp images were compared with linearly blended 120 kVp images (M_0.3; 30% of 80 kV, 70% of 140 kV spectrum). Attenuation of abscess rim enhancement, central necrosis, and several other anatomical landmarks were measured. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and rim-to-abscess CNR (raCNR) were calculated. Radiation dose was assessed as size-specific dose estimates (SSDE). Subjective image quality was assessed according to the European guidelines on quality criteria for CT. Interobserver agreement was calculated using the intraclass correlation coefficient (ICC). RESULTS: Attenuation of inflamed soft tissue (141.7 ± 16.3 versus 93.7 ± 9.3 HU, p < 0.001), CNR (9.6 ± 4.8 versus 5.6 ± 3.8, p = 0.001), raCNR (14.3 ± 5.9 versus 12.4 ± 4.4, p = 0.02), and subjective image sharpness (3.6 ± 0.6 versus 2.8 ± 0.7, p < 0.001) were significantly increased in the 80 kVp compared to 120 kVp, whereas subjective and objective image noise were significantly increased with 80 kVp acquisition (p < 0.001). Overall interobserver agreement was almost perfect (ICC, 0.87). Calculated SSDE of 80 kVp acquisition was decreased by 49.7% compared to 120 kVp (10.58 ± 0.76 versus 21.04 ± 1.43 mGy, p < 0.001). CONCLUSION: Low-tube-voltage 80 kVp neck CT provides increased enhancement of soft-tissue inflammation, CNR, raCNR, and improved abscess delineation in patients with PTA compared to standard 120 kVp acquisition while resulting in a significant reduction of radiation exposure.

[Q fever: not just in sheep]. / Q-koorts: niet alleen bij schapen.

Four patients, a woman aged 41 years and 3 men aged 12, 47 and 44 years, developed high fever after returning from a farm vacation in the Ardèche (France). They also suffered from severe headache, a painful tightness of the chest, abdominal pain or myalgia. Other symptoms were shivers, tiredness and a cough. While physical examination revealed few abnormalities, the chest X-ray in 3 patients showed an atypical pneumonia. One of these patients developed dural venous sinus thrombosis with increased intraspinal pressure. This patient also showed signs of a slight hepatitis. Serological investigation revealed that all 4 patients were suffering from acute Q fever, a zoonosis caused by the Coxiella burnetii bacterium. All 4 had been present at lambing and sheep-shearing. The patients with pneumonia were treated with antibiotics. All 4 patients recovered well. It is known that animal birth products in particular can contain large numbers of bacteria and therefore be highly infectious.

[Acute and chronic Q fever; epidemiology, symptoms, diagnosis and therapy of infection caused by Coxiella burnetii]. / Acute en chronische Q-koorts; epidemiologie, symptomen, diagnostiek en therapie van infecties met Coxiella burnetii.

Q fever is a zoonosis caused by Coxiella burnetii, an obligate intracellular bacterium. Domestic ungulates and parturient cats are the primary reservoirs of infection. The animals excrete the bacterium in urine, faeces, milk and amniotic fluid. After desiccation the micro-organism spreads via aerosols. After inhalation or ingestion and an incubation period of 2-6 weeks acute Q fever may develop with atypical pneumonia and hepatitis as major clinical symptoms. The infection also may present as a flu-like illness or remain asymptomatic. Generally, the prognosis is favourable. However, endocarditis or another chronic form of Q fever occasionally develops with possibly fatal outcome. Diagnosis relies upon serologic testing with an indirect immunofluorescence method. Doxycycline is the antibiotic of choice in the treatment of Q fever. Endocarditis needs therapy for years with the addition of rifampin or hydroxychloroquine. Q fever is poorly recognised due to the variety of clinical presentations.

Performance of iterative image reconstruction in CT of the paranasal sinuses: a phantom study.

BACKGROUND AND PURPOSE: CT in low dose technique is the criterion standard imaging modality for evaluation of the paranasal sinus. Our aim was to evaluate the dose-reduction potential of a recently available sinogram-affirmed iterative reconstruction technique, regarding noise, image quality, and time duration when evaluating this region. MATERIALS AND METHODS: CT was performed on a phantom head at different tube voltages (120 kV, 100 kV) and currents (100 mAs, 50 mAs, 25 mAs). Each protocol was reconstructed (in soft tissue and bony kernel) by using standard filtered back-projection and 5 different SAFIRE strengths, and image noise was evaluated. Subjective image quality was evaluated on noise-aligned image triplets acquired at tube currents of 100% (FBP), 50% (SAFIRE), and 25% (SAFIRE) by using a 5-point scale (1 = worst, 5 = best). The time duration for image reconstruction was noted for calculations with FBP and SAFIRE. RESULTS: SAFIRE reduced image noise by 15%-85%, depending on the iterative strength, rendering kernel, and dose parameters. Noise reduction was stronger at a bone kernel algorithm both in 1- and 3-mm images (P < .05). Subjective quality evaluation of the noise-adapted images showed preference for those acquired at 100% tube current with FBP (4.7-5.0) versus 50% dose with SAFIRE (3.4-4.4) versus 25% dose with SAFIRE (2.0-3.1). The time duration for FBP image sets was 2.9-6.6 images per second versus SAFIRE with 0.9-1.6 images per second. CONCLUSIONS: For CT of the paranasal sinus, SAFIRE algorithms are suitable for image-noise reduction. Because image quality decreases with dosage, careful choice of the appropriate iterative method is necessary to achieve an optimal balance between image noise and quality.

[Robot-assisted biopsies in a high-field MRI system - first clinical results]. / Roboterunterstützte Punktion in einem Hochfeld-Kernspintomografen - erste klinische Ergebnisse.

PURPOSE: The purpose of this study was to examine the clinical use of MR-guided biopsies in patients with suspicious lesions using a new MR-compatible assistance system in a high-field MR system. MATERIALS AND METHODS: Six patients with suspicious focal lesions in various anatomic regions underwent percutanous biopsy in a high-field MR system (1.5 T, Magnetom Espree, Siemens) using a new MR-compatible assistance system (Innomotion). The procedures were planned and guided using T 1-weighted FLASH and TrueFISP sequences. A servopneumatic drive then moved the guiding arm automatically to the insertion point. An MRI compatible 15G biopsy system (Somatex) was introduced by a physician guided by the needle holder and multiple biopsies were performed using the coaxial technique. The feasibility, duration of the intervention and biopsy findings were analyzed. RESULTS: The proposed new system allows accurate punctures in a high-field MR system. The assistance device did not interfere with the image quality, and guided the needle virtually exactly as planned. Histological examination could be conducted on every patient. The lesion was malignant in four cases, and an infectious etiology was diagnosed for the two remaining lesions. Regarding the differentiation of anatomical and pathological structures and position monitoring of the insertion needle, TrueFISP images are to be given preference. The average intervention time was 41 minutes. Lesions up to 15.4 cm beneath the skin surface were punctured. CONCLUSION: The proposed MR-guided assistance system can be successfully utilized in a high-field MR system for accurate punctures of even deep lesions in various anatomic regions.