Computed tomography of the chest with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination: preliminary observations

Objectives: The purpose of this study was to assess the diagnostic image quality of ultra-low-dose chest computed tomography (ULD-CT) obtained with a radiation dose comparable to chest radiography and reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard dose diagnostic CT (SDD-CT) or low-dose diagnostic CT (LDD-CT) reconstructed with FBP alone. Methods: Unenhanced chest CT images of 42 patients acquired with ULD-CT were compared with images obtained with SDD-CT or LDD-CT in the same examination. Noise measurements and image quality, based on conspicuity of chest lesions on all CT data sets were assessed on a five-point scale. Results: The radiation dose of ULD-CT was 0.16 ± 0.006mSv compared with 11.2 ± 2.7mSv for SDD-CT (P < 0.0001) and 2.7 ± 0.9mSv for LDD-CT. Image quality of ULD-CT increased significantly when using MBIR compared with FBP or ASIR (P < 0.001). ULD-CT reconstructed with MBIR enabled to detect as many non-calcified pulmonary nodules as seen on SDD-CT or LDD-CT. However, image quality of ULD-CT was clearly inferior for characterisation of ground glass opacities or emphysema. Conclusion: Model-based iterative reconstruction allows detection of pulmonary nodules with ULD-CT with radiation exposure in the range of a posterior to anterior (PA) and lateral chest X-ray. Key Points : • Radiation dose is a key concern with the increased use of thoracic CT • Ultra-low-dose chest CT approximates the radiation dose of conventional chest radiography • Ultra-low-dose chest CT can be of diagnostic quality • Solid pulmonary nodules are clearly depicted on ultra-low-dose chest C

Tomodensitométrie thoracique à dose de radiation très basse : utilisation dans la pratique clinique

L'algorithme de reconstruction itérative de deuxième génération MBIR (Model Based Iterative Reconstruction) est une nouvelle méthode de reconstruction en tomodensitométrie, qui offre une diminution du bruit avec le potentiel d'une dose d'irradiation d'acquisition également diminuée, mais sans dégradation de la qualité et de la valeur diagnostique des images. Nous avons étudié la qualité des images scannographiques acquises au niveau du thorax, sans injection de produit de contraste intraveineux, reconstruites par MBIR avec une dose d'irradiation équivalente à la dose d'une radiographie thoracique face et profil et nous avons conclu que cette méthode permet la détection de nodules pulmonaires. Nous avons comparé la qualité des images d'une angiographie pulmonaire tomodensitométrique (CTPA) de protocole habituel avec une angiographie pulmonaire tomodensitométrique en mA bas reconstruit par MBIR et nous avons pu démontrer que les deux acquisitions sont équivalentes et la deuxième méthode permet la réduction de la dose ainsi que l'amélioration des rapports signal et contraste sur bruit dans les vaisseaux pulmonaires

Colovesical fistula causing an uncommon reason for failure of computed tomography colonography: a case report

Abstract Introduction Computed tomography colonography, or virtual colonoscopy, is a good alternative to optical colonoscopy. However, suboptimal patient preparation or colon distension may reduce the diagnostic accuracy of this imaging technique. Case presentation We report the case of an 83-year-old Caucasian woman who presented with a five-month history of pneumaturia and fecaluria and an acute episode of macrohematuria, leading to a high clinical suspicion of a colovesical fistula. The fistula was confirmed by standard contrast-enhanced computed tomography. Optical colonoscopy was performed to exclude the presence of an underlying colonic neoplasm. Since optical colonoscopy was incomplete, computed tomography colonography was performed, but also failed due to inadequate colon distension. The insufflated air directly accumulated within the bladder via the large fistula. Conclusions Clinicians should consider colovesical fistula as a potential reason for computed tomography colonography failure.</p

Colovesical fistula causing an uncommon reason for failure of computed tomography colonography: a case report

Computed tomography colonography, or virtual colonoscopy, is a good alternative to optical colonoscopy. However, suboptimal patient preparation or colon distension may reduce the diagnostic accuracy of this imaging technique

Spontaneous lesser omental herniation resolved by laparoscopic surgery : case report and systematic literature review

Background: Despite its extremely low incidence, intra-abdominal herniation through the lesser omentum is associated with a high mortality rate and must be recognized early and treated urgently. To overcome a lack of data on the management of this condition, we collected and reviewed all the reported cases of operated lesser omental hernia and presented the case of a patient treated by laparoscopy for an isolated lesser omental hernia. Methods: According to PRISMA guidelines and using PubMed, Cochrane Library, and Web of Science, a systematic literature review of cases of lesser omental hernia treated by surgery was performed on February 12, 2023. Results: Of 482 articles, 30 were included for analysis and only 9 articles presented an isolated hernia through the lesser omentum. Among these, 4 patients were female and the median age was 38. Upper abdominal pain and vomiting were reported in 7 out of 9 patients. The small bowel was responsible for 78% (7/9) of all lesser omental herniations. All of them were treated by laparotomy. In addition, we describe the case of a 65-year-old woman without prior surgical history who was treated by laparoscopy for a spontaneous closed loop hernia through the lesser omentum without any other associated hernias. Conclusion: Mostly associated with prior surgery or trauma, this type of herniation could sometimes occur spontaneously without any sign of peritonitis. Due to the high mortality rate, internal abdominal hernias should always be ruled out with a CT scan in front of patients presenting with persisting acute abdominal pain and no alternative diagnosis.</p

Feasibility of synthetic MRI in knee imaging in routine practice

Synthetic magnetic resonance (MR) is a method allowing reduction of examination time and access to quantitative imaging

Radiomics and Machine Learning Differentiate Soft-Tissue Lipoma and Liposarcoma Better than Musculoskeletal Radiologists

Distinguishing lipoma from liposarcoma is challenging on conventional MRI examination. In case of uncertain diagnosis following MRI, further invasive procedure (percutaneous biopsy or surgery) is often required to allow for diagnosis based on histopathological examination. Radiomics and machine learning allow for several types of pathologies encountered on radiological images to be automatically and reliably distinguished. The aim of the study was to assess the contribution of radiomics and machine learning in the differentiation between soft-tissue lipoma and liposarcoma on preoperative MRI and to assess the diagnostic accuracy of a machine-learning model compared to musculoskeletal radiologists. 86 radiomics features were retrospectively extracted from volume-of-interest on T1-weighted spin-echo 1.5 and 3.0 Tesla MRI of 38 soft-tissue tumors (24 lipomas and 14 liposarcomas, based on histopathological diagnosis). These radiomics features were then used to train a machine-learning classifier to distinguish lipoma and liposarcoma. The generalization performance of the machine-learning model was assessed using Monte-Carlo cross-validation and receiver operating characteristic curve analysis (ROC-AUC). Finally, the performance of the machine-learning model was compared to the accuracy of three specialized musculoskeletal radiologists using the McNemar test. Machine-learning classifier accurately distinguished lipoma and liposarcoma, with a ROC-AUC of 0.926. Notably, it performed better than the three specialized musculoskeletal radiologists reviewing the same patients, who achieved ROC-AUC of 0.685, 0.805, and 0.785. Despite being developed on few cases, the trained machine-learning classifier accurately distinguishes lipoma and liposarcoma on preoperative MRI, with better performance than specialized musculoskeletal radiologists

Image quality of low mA CT pulmonary angiography reconstructed with model based iterative reconstruction versus standard CT pulmonary angiography reconstructed with filtered back projection: an equivalency trial

Objective: To determine whether CT pulmonary angiography (CTPA) using low mA setting reconstructed with model-based iterative reconstruction (MBIR) is equivalent to routine CTPA reconstructed with filtered back projection (FBP). Methods: This prospective study was approved by the institutional review board and patients provided written informed consent. Eighty-two patients were examined with a low mA MBIR-CTPA (100kV, 20mA) and 82 patients with a standard FBP-CTPA (100kV, 250mA). Region of interests were drawn in nine pulmonary vessels; signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. A five-point scale was used to subjectively evaluate the image quality of FBP-CTPA and low mA MBIR-CTPA. Results: Compared to routine FBP-CTPA, low mA MBIR-CTPA showed no differences in the attenuation measured in nine pulmonary vessels, higher SNR (56 ± 19 vs 43 ± 20, p < 0.0001) and higher CNR (50 ± 17 vs 38 ± 18, p < 0.0001) despite a dose reduction of 93% (p < 0.0001). The subjective image quality of low mA MBIR-CTPA was quoted as diagnostic in 98% of the cases for patient with body mass index less than 30kg/m2. Conclusion: Low mA MBIR-CTPA is equivalent to routine FBP-CTPA and allows a significant dose reduction while improving SNR and CNR in the pulmonary vessels, as compared with routine FBP-CTPA. Key Points : • Low mA MBIR-CTPA is equivalent to routine FBP-CTPA. • MBIR-CTPA may be achieved with drastic (93%) dose reduction. • Low mA MBIR-CTPA should be studied in the setting of suspected PE

Compressed sensing MRI of different organs: ready for clinical daily practice?

The aim was to evaluate the image quality and sensitivity to artifacts of compressed sensing (CS) acceleration technique, applied to 3D or breath-hold sequences in different clinical applications from brain to knee