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

Urinary stone detection and characterisation with dual-energy CT urography after furosemide intravenous injection: preliminary results

Objectives: To investigate the added advantage of IV furosemide injection and the subsequent urine dilution in the detection of urinary calculi in the excretory phase of dual-source dual-energy (DE) computed tomography (CT) urography, and to investigate the feasibility of characterising the calculi through diluted urine. Methods: Twenty-three urinary calculi were detected in 116 patients who underwent DECT urography for macroscopic haematuria with a split bolus two- or three-acquisition protocol, including a true unenhanced series and at least a mixed nephrographic excretory phase. Virtual unenhanced images were reconstructed from contrast-enhanced DE data. Calculi were recorded on all series and characterised based on their X-ray absorption characteristics at 100kVp and 140kVp in both true unenhanced and nephrographic excretory phase series. Results: All calculi with a diameter more than 2mm were detected in the virtual unenhanced phase and in the nephrographic excretory phase. Thirteen of these calculi could be characterised in the true unenhanced phase and in the mixed nephrographic excretory phase. The results were strictly identical for both phases, six of them being recognised as non-uric acid calculi and seven as uric acid calculi. Conclusions: Mixed nephrographic excretory phase DECT after furosemide administration allows both detection and characterisation of clinically significant calculi, through the diluted urine. Key points: • Urinary tract stones can be detected on excretory phase through diluted urine. • Urinary tract stone characterisation with dual-energy CT (DECT) is possible through diluted urine. • A dual energy split-bolus CT urography simultaneously enables urinary stone detection and characterisation

Cine and tagged cardiovascular magnetic resonance imaging in normal rat at 1.5 T: a rest and stress study

BACKGROUND: The purpose of this study was to measure regional contractile function in the normal rat using cardiac cine and tagged cardiovascular magnetic resonance (CMR) during incremental low doses of dobutamine and at rest. METHODS: Five rats were investigated for invasive left ventricle pressure measurements and five additional rats were imaged on a clinical 1.5 T MR system using a cine sequence (11-20 phases per cycle, 0.28/0.28/2 mm) and a C-SPAMM tag sequence (18-25 phases per cycle, 0.63/1.79/3 mm, tag spacing 1.25 mm). For each slice, wall thickening (WT) and circumferential strains (CS) were calculated at rest and at stress (2.5, 5 and 10 microg/min/kg of dobutamine). RESULTS: Good cine and tagged images were obtained in all the rats even at higher heart rate (300-440 bpm). Ejection fraction and left ventricular (LV) end-systolic volume showed significant changes after each dobutamine perfusion dose (p < 0.001). Tagged CMR had the capacity to resolve the CS transmural gradient and showed a significant increase of both WT and CS at stress compared to rest. Intra and interobserver study showed less variability for the tagged technique. In rats in which a LV catheter was placed, dobutamine produced a significant increase of heart rate, LV dP/dtmax and LV pressure significantly already at the lowest infusion dose. CONCLUSION: Robust cardiac cine and tagging CMR measurements can be obtained in the rat under incremental dobutamine stress using a clinical 1.5 T MR scanner

Evolution of urogenital and breast imaging: from morphology to functional imaging

Urogenital and breast imaging plays a significant role in patient care in oncological and patients with other pathologic conditions. Despite the fact that the spectrum of pathologies is huge, in most domains, evolution of imaging allowed a transition from pure morphological studies towards more sophisticated techniques that allow tissue characterisation and incorporate functional information. In the following pages some of these evolutions will be described. The role of new CT techniques will be particularly discussed. Dual-energy CT (DECT) and its application in oncological and non-oncological urinary tract pathologies as well as in adrenal lesions characterisation will be presented. New CT techniques for exploration of urogenital fistulas, using functional information will be detailed. In another chapter, the evolution towards functional breast imaging will be discussed, with special mention of the role of multiparametric MR (MP-MR) and PET/MR in staging of breasts cancer patients

Etude de la valeur du CT double-énergie pour l'évaluation des pathologies de l'appareil urinaire

La tomodensitométrie à double-énergie (CTDE) est l'une des dernières évolutions dans le domaine de l'imagerie médicale. Elle a le potentiel de différencier les matières sur la base de leur absorption de différentes énergies des rayons-X. Ainsi, elle permet de calculer, après l'injection de produits de contraste iodés, la concentration d'iode dans les tissus, mais aussi de prédire la composition chimique de certaines structures. Aux Hôpitaux Universitaires de Genève, nous avons établi un protocole dédié pour la CTDE avec produit de contraste iodé. Nous avons étudié la valeur ajoutée de ce protocole pour la détection des tumeurs urothéliales ainsi que sa capacité de caractériser les calculs urinaires à travers l'urine modérément opacifiée suite à l'injection de Furosémide. Nous avons pu démontrer que, dans ces deux situations cliniques, on peut se passer de l'acquisition sans contraste et ainsi réduire de façon significative la dose d'irradiation aux patients

Preservation of fertility in non-Peutz-Jegher syndrome-associated ovarian sex cord tumour with annular tubules

We report the successful conservative management of a non-Peutz-Jegher syndrome-associated ovarian sex cord tumour with annular tubules in a 32-year-old patient. The patient underwent a unilateral salpingo-oophorectomy by laparoscopy, and conceived spontaneously approximately 6 months after the diagnosis. After a normal term pregnancy, she underwent a contralateral laparoscopic salpingo-oophorectomy with hysterectomy. The patient is now on hormone replacement therapy and, after 30 months of follow-up, continues to present no sign of disease recurrence

Pelvic splenosis mimicking a suspicious adnexal mass

A 58-year-old asymptomatic woman was referred to our gynecologic oncology unit for the management of a left adnexal mass found during a routine gynecologic examination. Her personal history included an emergency splenectomy at the age of 4 years old, following traumatic splenic laceration after a car accident. The patient's work-up (including transvaginal ultrasound and MRI) confirmed a pelvic solid mass, which was reported as suspicious for malignancy and classified as Ovarian-Adnexal Reporting &amp; Data System-MRI 5. An exploratory laparoscopy was performed, showing a reddish blue lesion located at the left broad ligament. Histologic analysis showed the presence of splenic tissue and normal adnexa. The postoperative follow-up was uneventful.Pelvic splenosis is a challenging diagnosis rarely made preoperatively due to concern for malignancy. In the presence of a pelvic mass, the collection of a detailed patient's history, including information about previous splenic rupture, might raise suspicion for pelvic splenosis

Diagnosis of urothelial tumors with a dedicated dual-source dual-energy MDCT protocol: preliminary results

The purpose of this study was to evaluate the diagnostic performance of a dedicated dual-source dual-energy MDCT (DECT) protocol for the detection of urothelial tumors

Incarcerated Grynfeltt-Lesshaft Hernia

Superior lumbar triangle hernia, also known as Grynfeltt-Lesshaft hernia, denotes a subtype of abdominal wall hernia, and more specifically of lumbar hernia, occurring between the 12th rib, the internal oblique muscle, and the quadratus lumborum muscle. We report the case of a 92-year-old female patient in which this form of hernia occurred, complicated by incarceration and acute bowel obstruction. The discussion contains a short résumé of the different kinds of abdominal wall hernias

The Clinical Added Value of Breast Cancer Imaging Using Hybrid PET/MR Imaging

Dedicated MR imaging is highly performant for the evaluation of the primary lesion and should regularly be added to whole-body PET/MR imaging for the initial staging. PET/MR imaging is highly sensitive for the detection of nodal involvement and could be combined with the high specificity of axillary second look ultrasound for the confirmation of the N staging. For M staging, with the exception of lung lesions, PET/MR imaging is superior to PET/computed tomography, at half the radiation dose. The predictive value of multiparametric imaging with PET/MR imaging holds promise to improve through radiomics and artificial intelligence