Myopericytoma of the Base of the Finger: Radiological and Pathological Description of a Rare Benign Entity.

A previously healthy 46-year-old woman presented with a mass lesion between the bases of the fourth and fifth fingers of the right hand. The mass had grown progressively over 2 years and started to cause practical difficulties in everyday life. Imaging depicted a hypervascular and well-circumscribed soft tissue tumor with imaging characteristics of a sarcoma. The lesion was treated surgically. The final diagnosis of the specimen upon pathology was a myopericytoma, a benign smooth-muscle cell neoplasm. Myopericytoma is a rare disease entity; however, it is important because it can mimic more ominous conditions.

Quarter-millimeter spectral coronary stent imaging with photon-counting CT: Initial experience.

PURPOSE: To evaluate the performance and clinical feasibility of 0.25 mm resolution mode of a dual-energy photon-counting detector (PCD) computed tomography (CT) system for coronary stent imaging and to compare the results to state-of-the-art dual-energy energy-integrating detector (EID) CT. MATERIALS AND METHODS: Coronary stents with different diameters (2.0-4.0 mm) were examined inside a coronary artery phantom consisting of plastic tubes filled with iodine-based and gadolinium-based contrast material diluted to approximate clinical concentrations (n = 18). EID images were acquired using 2nd and 3rd generation dual-source CT systems (SOMATOM Flash and SOMATOM Force, Siemens Healthcare) at 0.60 mm (defined as standard-resolution (SR)) isotropic voxel size. Radiation-dose matched PCD images were acquired using a human prototype PCD system (Siemens Healthcare) at 0.50 mm (SR) and 0.25 mm (HR) imaging modes. Images were reconstructed using optimized convolution kernels. RESULTS: Dual-energy HR PCD images significantly better stent lumen visualization (median: 69.5%, IQR: 61.2-78.9%) over dual-energy EID, and standard-resolution PCD images (median: 53.2-57.4%, all P < 0.01). HR PCD acquisitions reconstructed at SR image voxel size showed 25.3% lower image noise compared to SR PCD acquisitions (P < 0.001). High-resolution iodine and gadolinium maps, as well as virtual monoenergetic images, were calculated from the PCD data and enabled estimation of contrast agent concentration in the lumen without interference from the coronary stent. CONCLUSION: HR spectral PCD imaging significantly improves coronary stent lumen visibility over dual-energy EID. When the PCD-HR data was reconstructed into standard voxel sizes (0.5 mm isotropic) the image noise decreased by 25% compared to SR acquisition of PCD. Both dual-energy systems were consistent in estimating contrast agent concentrations.

A prospective clinical study using a dynamic contrast-enhanced CT-protocol for detection of colorectal liver metastases.

OBJECTIVE: To evaluate a dynamic contrast-enhanced CT-protocol and compare this method with standard of care monophasic portovenous CT for detection of colorectal liver metastases. MATERIALS AND METHODS: A dynamic contrast-enhanced CT protocol was developed to detect liver metastasis in patients suffering from colorectal cancer, in clinical practice. The study was approved by the Hospital Ethics Committee. Written informed consent was obtained from all patients. 135 patients were included in this prospective study. All patients were naive to treatment. A dynamic contrast-enhanced CT was performed, followed by routine monophasic portovenous CT of thorax-abdomen-pelvis. 42 of these patients presented with liver metastasis. The number and lesion conspicuity of detected liver metastasis on dynamic contrast-enhanced CT using perfusion maps, was compared to monophasic CT. RESULTS: 135 patients were included, of which 42 presented with metastases to the liver. Dynamic contrast-enhanced CT outperformed portovenous CT for detection as well as conspicuity of colorectal liver metastasis, at a relatively low dose increment. Wilcoxon Signed Rank test had a p-value of 0.016 and <0.001 respectively for detection and conspicuity of colorectal liver metastasis. CONCLUSION: Dynamic contrast-enhanced CT increases the detection of colorectal liver metastasis, especially for lesions smaller than 15 mm, when compared to monophasic portovenous CT. Dynamic contrast-enhanced CT also has the added advantage of improved lesion conspicuity, which can positively influence reader confidence and clinical workflow.

Saccular pseudoaneurysm of the left common carotid artery in an adolescent: Management with a covered stent.

An adolescent patient with a previous history of surgical repair for interrupted aortic arch type B presented with an asymptomatic, saccular pseudoaneurysm of the proximal, common left carotid artery, identified on a follow-up magnetic resonance angiography of the thoracic large vessels. The pseudoaneurysm was successfully excluded with a covered stent. Clinical and radiological follow-up after 2 years was uneventful.

Cystic Periventricular Leukomalacia: A Condition that Became Uncommon in the Premature Neonate, Diagnosed on Transcranial Ultrasound.

A preterm neonate was born in our center, as a part of a diamniotic dichorionic twin pregnancy, complicated with placental abruption with need for urgent cesarean section at 26 weeks of gestation. After a difficult neonatal start with respiratory and cardiovascular problems, the neonate safely reached the neonatal intensive care unit. Further work-up and supportive care was continued. Transcranial ultrasound imaging through the anterior fontanel was part of this work-up. Initial examinations were not normal, and showed cystic lesions along the germinal matrix, without hydrocephalus or parenchymal lesions. The findings were highly suggestive of sequellae of grade II germinal matrix bleed according to Papile and Burstein (Image A). Further follow-up examinations by means of ultrasound depicted a discrete enlargement of the lateral ventricles over time (Image B). Later on development of widespread periventricular cystic lesions became apparent (Image C and D). The cystic lesions are located in the periventricular white matter, and are not attached to the ventricles. This finding makes cystic periventricular leukomalacia the preferred diagnosis, and makes venous infarction with cystic alterations secondary to germinal matrix bleeding less likely.

Three-dimensional knee kinematics by conventional gait analysis for eleven motor tasks of daily living: typical patterns and repeatability.

The availability of detailed knee kinematic data during various activities can facilitate clinical studies of this joint. To describe in detail normal knee joint rotations in all three anatomical planes, 25 healthy subjects (aged 22-49 years) performed eleven motor tasks, including walking, step ascent and descent, each with and without sidestep or crossover turns, chair rise, mild and deep squats, and forward lunge. Kinematic data were obtained with a conventional lower-body gait analysis protocol over three trials per task. To assess the repeatability with standard indices, a representative subset of 10 subjects underwent three repetitions of the entire motion capture session. Extracted parameters with good repeatability included maximum and minimum axial rotation during turning, local extremes of the flexion curves during gait tasks, and stride times. These specific repeatable parameters can be used for task selection or power analysis when planning future clinical studies.