Imaging of articular pathology: MRI, CT, arthrography

The effect of CT and MRI with and without arthrography on the appearance of the feline carpal ligaments

Background

The current diagnosis of feline carpal injuries is based on radiographic examination including stress views and computed tomography; however, these techniques do not allow for direct evaluation of the carpal ligaments. The purpose of this cadaveric study was to assess the ability of CT arthrography (CTA) and MR arthrography (MRA) to provide this information using a single contrast mixture. A protocol for intra-articular injection of the feline carpus was also described. A contrast solution containing gadolinium and iohexol with a 50% gadolinium solution (Magnevist—gadolinium 0.5 mmol/mL diluted to a 0.05 mmol/mL solution) and 50% of iodine (Iohexol—iodine 300mgI/mL) was injected into the antebrachiocarpal and middle carpal joints of feline carpi using fluoroscopic guidance.

Results

CTA allowed for identification of intra-articular ligaments and the silhouette of select extra-articular ligaments when there was adequate joint distension, however it was not considered to be superior to MRI. MRA allowed for improved identification of the dorsal radiocarpal, accessorioulnocarpal, accessorioquartile, short ulnar and short radial collateral ligaments.

Conclusion

In this ex-vivo study, combined CTA and MRA enhanced the appearance of the feline carpal ligaments and may provide a foundation for future studies in the diagnosis of carpal injuries.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03463-6.

Congenital coronary artery anomalies: a bridge from embryology to anatomy and pathophysiology--a position statement of the development, anatomy, and pathology ESC Working Group

Congenital coronary artery anomalies are of major significance in clinical cardiology and cardiac surgery due to their association with myocardial ischaemia and sudden death. Such anomalies are detectable by imaging modalities and, according to various definitions, their prevalence ranges from 0.21 to 5.79%. This consensus document from the Development, Anatomy and Pathology Working Group of the European Society of Cardiology aims to provide: (i) a definition of normality that refers to essential anatomical and embryological features of coronary vessels, based on the integrated analysis of studies of normal and abnormal coronary embryogenesis and pathophysiology; (ii) an animal model-based systematic survey of the molecular and cellular mechanisms that regulate coronary blood vessel development; (iii) an organization of the wide spectrum of coronary artery anomalies, according to a comprehensive anatomical and embryological classification scheme; (iv) current knowledge of the pathophysiological mechanisms underlying symptoms and signs of coronary artery anomalies, with diagnostic and therapeutic implications. This document identifies the mosaic-like embryonic development of the coronary vascular system, as coronary cell types differentiate from multiple cell sources through an intricate network of molecular signals and haemodynamic cues, as the necessary framework for understanding the complex spectrum of coronary artery anomalies observed in human patients.

Gold nanoparticles allow detection of early-stage edema in mice via computed tomography imaging

Due to their high X-ray attenuation, gold nanoparticles (GNPs) emerged as preclinical contrast agents by giving high vasculature contrast. For this reason, GNPs are regularly applied for computed tomography (CT) imaging of tumors but not for the visualization of inflammation. The aim of this study was to evaluate the biocompatibility and applicability of preclinical GNPs (AuroVist™) of two different sizes (1.9 nm and 15 nm) for the detection of inflammation-associated phagocytes in early-stage edema. Both GNP variants were stable under in vitro conditions and achieved high micro-CT (mCT) contrast after embedment into agarose. Fifteen-nanometer GNPs were detected after uptake into macrophages via mCT imaging exhibiting higher X-ray contrast than cells treated with 1.9 nm GNPs and untreated ones. Both 1.9 nm and 15 nm GNPs exhibited good biocompatibility on murine macrophages according to ATP and cellular dehydrogenase levels. Reactive oxygen species levels produced by phagocytic cells decreased significantly (P≤0.05) after co-incubation with GNPs regardless of the size of the nanoparticle (NP) in comparison to untreated control cells. In vivo mCT studies of inflammation imaging revealed that GNPs with a diameter of 15 nm accumulated within subcutaneous edema 2 hours after injection with a maximum signaling 8 hours postinjection and could be detected up to 48 hours within the edema region. In contrast, 1.9 nm GNPs were not shown to accumulate at the site of the inflammation region and were mostly excreted via the renal system 2–4 hours after injection. In conclusion, our study demonstrated that both GNP variants (1.9 nm and 15 nm) were stable and biocompatible under in vitro conditions. However, only 15 nm NPs have the potential as contrast agent for phagocyte labeling and applications in CT imaging of inflammation on a cellular level.

Glenohumeral joint instability

Due to the configuration of its bony elements, the glenohumeral joint is the most mobile joint of the body, but also an inherently unstable articulation. Stabilization of the joint is linked to a complex balance between static and dynamic soft tissue stabilizers. Because of complex biomechanics, and the existence of numerous classifications and acronyms to describe shoulder instability lesions, this remains a daunting topic for most radiologists. In this article we provide a brief review of the anatomy of the glenohumeral joint, as well as the classifications and the pathogenesis of shoulder instability. Technical aspects related to the available imaging techniques (including computed tomography [CT] arthrography, magnetic resonance imaging [MRI], and MR arthrography) are reviewed. We then describe the imaging findings related to shoulder instability, focusing on those elements that are important to the clinician.

Multidetector computed tomography evaluation of bony fragments and donor sites in acute patellar dislocation

BACKGROUND

Patellar dislocation is frequently associated with bony fragments that are difficult to see on radiographs. MRI or MDCT are often used to rule out or characterize these bony fragments.

PURPOSE

To assess the use of MDCT for locating bony fragments and donor sites in patients with acute patellar dislocation, and to test whether sizes and quantity of bony fragments differ between first-time dislocations and recurrent dislocations.

MATERIAL AND METHODS

Retrospective data from two hospitals during a 96-month period were collected, and a total of 46 patients (mean age 27 years, range 9-69 years) that had sustained an acute patellar dislocation (22 first-time, 24 recurrent) were identified. Size, location and donor site of bony fragments were evaluated on MDCT images. Surgical correlation was available for 22 of 46 patients.

RESULTS

On MDCT images, the likely donor site could be identified in 62 of 71 (87%) bony fragments. Of the bony fragments that were seen on MDCT images, 40 of 68 (59%) were not seen on AP and lateral views of the conventional radiographs. There was no significant difference in size of bony fragments between first-time or recurrent dislocators (p=0.77). The average number of bony fragments were 2.1 and 1.0 in first-time and recurrent dislocators, respectively. The location and donor site of bony fragments was similar between two patients groups.

CONCLUSION

MDCT is a suitable imaging method to locate bony fragments and donor sites. The number of bony fragments seems to be higher in first-time dislocators than recurrent dislocators, otherwise findings between the two patient groups were similar.

CT arthrography: in vitro evaluation of single and dual energy for optimization of technique

The purpose of this study was to optimize CT arthrography technique and determine if dual energy CT (DECT) can provide any benefit over single energy CT (SECT). Iodinated contrast attenuation at different concentrations was measured using DECT and SECT at different beam energies (140, 120, and 80 kVp). Dose and noise were measured on phantoms at different tube currents. Three bovine femoral condyles with artificially created cartilage defects were scanned with dose-equivalent protocols. Contrast-to-noise ratio (CNR) between cartilage and iodine was measured, and the appearance of cartilage defects was graded by two readers. DECT scans were post-processed for iodine quantification. The beam energy 80 kVp had the highest iodine signal, 50% greater than DECT, 75% greater than 120 kVp, and 100% greater than 140 kVp. Noise was nearly identical for all techniques when dose was matched. The 80 kVp level had the highest CNR, 25% higher than 120 kVp and DECT, and 33% greater than 140 kVp. The 80 kVp technique was also preferred by both readers. DECT iodine quantification was significantly limited by the post-processing application, noise, and beam hardening. In this in-vitro study, the SECT 80 kVp CT arthrography technique was superior to currently performed 120 and 140 kVP SECT techniques and DECT.

CT arthrography, MR arthrography, PET, and scintigraphy in osteoarthritis

CT arthrography and MR arthrography are accurate methods for the study of surface cartilage lesions and cartilage loss. They also provide information on subchondral bone and marrow changes, and ligaments and meniscal lesions that can be associated with osteoarthritis. Nuclear medicine also offers new insights in the assessment of the disease. This article discusses the strengths and limitations of CT arthrography and MR arthrography. It also highlights nuclear medicine methods that may be relevant to the study of osteoarthritis in research and clinical practice.

Ultrasonographic, computed tomographic and magnetic resonance imaging anatomy of the normal canine stifle joint

Ultrasonographic (US), magnetic resonance (MR) and computed tomographic (CT) images of normal canine stifle joints were obtained and compared with plastinated cross-sectional slices of cadaver specimens from the same dogs. The bony and articular structures were identified and correlated with the three diagnostic imaging modalities. These results provide an atlas of normal cross-sectional US, MR and CT anatomy of the canine stifle, which can be used for the interpretation of stifle images from any of these imaging modalities.

CT and MR imaging features of oral and maxillofacial hemangioma and vascular malformation

PURPOSE

To present CT and MR images and compare CT and MRI features of oral and maxillofacial hemangioma and vascular malformation.

MATERIAL AND METHODS

The clinical materials consisted of nine vascular tumors from nine patients examined by both CT and MR scanners between November 1996 and March 2002. Both CT and MR images were retrospectively evaluated. The following features were evaluated: detectability of the lesion, border of the lesion, tumor margin, inner nature of the lesion, contrast between the lesion and surrounding tissues, degree of CT value or signal intensity of the lesion, enhancement of contrast medium, inner nature of the lesion after contrast medium injection, detectability of phleboliths and detectability of bone resorption.

RESULTS

In two patients, we could not detect lesions in any of the CT images because of artifacts from the teeth and/or dental restorations. In contrast, we could detect all lesions on T2-weighted MR images and contrast enhanced T1-weighted MR images. On T2-weighted images with the fat suppression technique, tumors tended to show higher contrast compared to surrounding tissues.

CONCLUSION

T2-weighted images with the fat suppression technique and contrast enhanced T1-weighted images with the fat suppression technique were very useful for the detection of vascular lesions. Observation from optional directions (axial, coronal and sagittal images) seemed appropriate for delineating the extension of the tumor. Phleboliths detectability on CT images was superior to that on MR images.

MRI of the pelvic ring joints postpartum: normal and pathological findings

PURPOSE

To assess the joints of the pelvic ring postpartum and to discern normal postpartum findings and pathologic lesions using MRI.

MATERIALS AND METHODS

MR images were obtained in six women with severe pelvic ring pain after delivery, in 13 women after uncomplicated vaginal delivery, and in 11 healthy, nulliparous non-pregnant volunteers. Distances of the pubic gap, signal intensities of the pubic cartilage, and signal changes of the pelvic ring bones were determined and evaluated.

RESULTS

Both postpartum groups had significantly larger distances of the interpubic gap compared to the nulliparous group (P = 0.0002). The mean signal intensity of cartilage of the symphysis pubis was significantly different on the T1-weighted and T2-weighted MR images in postpartum women compared to nulliparous women (P = 0.001), indicating a higher water content of the pubic cartilage. 13 of all 19 postpartum women had bruises of parasymphyseal pubic bones. One pubic symphysis rupture and one sacral stress fracture were detected in two symptomatic women.

CONCLUSION

MR imaging is a useful adjunct to clinical examination to identify patients with lesions of the pelvic ring postpartum. MRI of the pelvic ring of asymptomatic postpartum women can demonstrate signal changes of the pubic cartilage and small bruises of the pubic bones.

Coronary arterial anatomy in tetralogy of Fallot: morphological and clinical correlations

OBJECTIVE

To clarify the problems in angiographic diagnosis of major coronary arteries crossing the right ventricular outflow tract.

DESIGN

A retrospective study with clinicomorphological correlations to ascertain any aberrant coronary arteries and variations in distribution of the normal right coronary arterial branches.

SETTING

Tertiary referral centre.

SUBJECTS

36 necropsy specimens together with the aortograms and surgical reports from 130 patients with tetralogy of Fallot.

RESULTS

A preventricular branch was found in 19% of cases with tetralogy of Fallot, but in none of 13 normal hearts. Aberrant origin of the anterior interventricular coronary artery was found in 14% of the specimens. The combination of "laid back" and straight lateral views, when reviewed retrospectively, identified this anomaly correctly in nine of 16 patients, with these findings confirmed at surgery in seven patients. A major branch initially thought to cross the outflow tract was shown retrospectively to be an infundibular artery in six, with surgical confirmation in four. It was a preventricular branch in another patient.

CONCLUSIONS

Using the laid back view alone, infundibular and preventricular branches may be mistaken for a major aberrant artery. A combination of laid back and straight lateral views is needed to avoid false positive diagnosis.