Imaging features of crystal-induced arthropathy

MR Imaging of the Hip: Infectious and Inflammatory Conditions

MR imaging is a useful tool in establishing the diagnosis of inflammation and/or infection in the hip joint and adjacent tissues, and in determining the extent of disease. In conjunction with clinical factors, MR imaging findings can help to narrow the differential diagnosis in individual cases and can guide decisions regarding biopsies, aspirations, or additional imaging.

Para-articular and intra-articular soft tissue lesions: Radiologic-pathologic correlation

Articular masses comprise various disease entities including benign or malignant proliferative processes and other non-neoplastic processes such as infection, deposition diseases, vascular malformations, and other lesions. Many diseases that lead to intra-articular or para-articular masses have distinct imaging features, particularly on MRI. Radiologists can localize masses to the joint space by knowing the articular anatomy and can reach a suggested diagnosis by looking at precise imaging findings. In this review article, we first define the concept of articular space (intraarticular, para-articular) and the normal joint anatomy and histology. We provide a general and comprehensive approach for evaluation of articular lesions on MRI. We then describe specific imaging and histologic features of typical benign and malignant soft tissue articular neoplasms and some non-neoplastic mimickers; and provide a radio-pathologic correlation of the different described entities.

Bilateral gluteus medius and minimus calcific tendonitis in a patient with previous bilateral calcific tendonitis of the shoulder: A case report

Calcific tendonitis of the gluteus medius and minimus tendons is a rare complication of hydroxyapatite deposition disease, with bilateral involvement even more so. Although patients can be asymptomatic, there is often an acute-on-chronic presentation of pain. We present a case of bilateral calcific tendonitis of the gluteus medius and minimus tendons on a background of previous bilateral rotator cuff calcific tendonitis in a middle-aged woman. This patient's long-standing history of multi-focal involvement required a multidisciplinary approach between orthopedics, rheumatology, and musculoskeletal radiology for optimal management, requiring different treatment options for different affected sites.

Clinical Relevance and Immunohistochemical Patterns of Silent Pituitary Adenomas: 10 Years of Single-centre Experience

BACKGROUND

Silent pituitary adenomas are clinically non-functional (i.e., without clinically evident pituitary hormone production).

INTRODUCTION

The aim of this study was to investigate subjects with silent pituitary adenomas for possible variations in their clinical status.

METHODS

A total of 102 patients who had undergone surgery for pituitary adenoma and had been diagnosed with silent pituitary adenoma was included in the study. The patients' preoperative and postoperative hormonal parameters and magnetic resonance imaging (MRI) features were collected, and pathological specimens were re-evaluated.

RESULTS

Immunohistochemistry results of the 102 patients were as follows: hormone-negative adenomas (n=35) 35.5%; FSH+LH-positivity (n=32) 31.3%; ACTH-positivity (n=11) 10.7%; α-subunit- positivity (n= 9) 8.8%; prolactin-positivity (n=8) 7.8%; GH-positivity (n=6) 5.4%; and plurihormonal adenoma (n=1). The mean sizes of SGA, SGHA, and SCA were 28.0±12.7, 30.0±16.0, and 27.7±8.9mm (p>0.05), respectively. With the exception of silent gonadotroph adenomas (SGAs), female gender dominance was shown in patients with silent growth hormone adenoma (SGHA) and silent corticotroph adenoma (SCA). Although no clinical relevance was observed in relation to hormonal excess, preoperative GH (4.21±4.6, vs. 0.27±0.36 p=0.00) was slightly more elevated in SGHA than in GH-negative adenomas. Additionally, preoperative basal ACTH values (47.3±28.7 vs. 23.9±14.4, p=0.003) were also higher in SCA compared to the other types. Our findings revealed SCAs to be of more aggressive behaviour than SGHAs and SGAs due to invasiveness in radiological imaging, their elevated re-operation, and postoperative ACTH values.

CONCLUSION

Silent pituitary adenomas represent a challenging diagnostic tumour group. Careful initial evaluation of patients with pituitary adenomas should consider any mild signs and symptoms of functionality, particularly in cases of GH- and ACTH-secreting adenomas.

Recent developments in advanced imaging in gout

The plain radiographic features of gout are well known; however, the sensitivity of plain radiographs alone for the detection of signs of gout is poor in acute disease. Radiographic abnormalities do not manifest until late in the disease process, after significant joint and soft tissue damage has already occurred. The advent of dual-energy computed tomography (DECT) has enabled the non-invasive diagnosis and quantification of gout by accurately confirming the presence and extent of urate crystals in joints and soft tissues, without the need for painful and often unreliable soft tissue biopsy or joint aspiration. Specific ultrasound findings have been identified and may also be used to aid diagnosis. Both ultrasound and magnetic resonance imaging (MRI) may be used for the measurement of disease extent, monitoring of disease activity or treatment response, although MRI findings are nonspecific. In this article we summarize the imaging findings and diagnostic utility of plain radiographs, ultrasound, DECT, MRI and nuclear medicine studies in the assessment as well as the implications and utility these tools have for measuring disease burden and therapeutic response.

Gout: An old disease in new perspective - A review

Gout is a picturesque presentation of uric acid disturbance. It is the most well understood and described type of arthritis. Its epidemiology is studied. New insights into the pathophysiology of hyperuricemia and gouty arthritis; acute and chronic allow for an even better understanding of the disease. The role of genetic predisposition is becoming more evident. The clinical picture of gout is divided into asymptomatic hyperuricemia, acute gouty arthritis, intercritical period, and chronic tophaceous gout. Diagnosis is based on laboratory and radiological features. The gold standard of diagnosis is identification of characteristic MSU crystals in the synovial fluid using polarized light microscopy. Imaging modalities include conventional radiography, ultrasonography, conventional CT, Dual-Energy CT, Magnetic Resonance Imaging, nuclear scintigraphy, and positron emission tomography. There is remarkable progress in the application of ultrasonography and Dual-Energy CT which is bound to influence the diagnosis, staging, follow-up, and clinical research in the field. Management of gout includes management of flares, chronic gout and prevention of flares, as well as management of comorbidities. Newer drugs in the pharmacological armamentarium are proving successful and supplement older ones. Other important points in its management include patient education, diet and life style changes, as well as cessation of hyperuricemic drugs.

Imaging in Gout and Other Crystal-Related Arthropathies

In this article, the authors consider the manifestations of intraarticular and periarticular crystal deposits. Most cases of crystal deposits are asymptomatic and represent incidental findings at imaging. In symptomatic arthropathies, imaging can play an important role in the diagnosis and assessment of disease progression and the extent of crystal deposits. Conventional radiography is the most common imaging modality. But ultrasound, conventional computerized tomography (CT), dual-energy CT, and MRI play an increasing role. The authors review typical radiographic features of crystal-induced arthropathies and findings that help to differentiate them. The authors also emphasize the increasing role of complementary imaging techniques.

The radiographic and MRI features of gout referred as suspected soft tissue sarcoma: a review of the literature and findings from 27 cases

Gout has been termed the "great mimicker", for its ability to resemble other pathological conditions. Whilst the typical imaging features of gout are well described, there is a relative paucity of literature describing more challenging cases of gout, where a malignant tumour has been considered in the differential diagnosis. The aim of this article is to provide an overview of the radiographic and MRI features of 27 cases of gout that were initially referred to our centre as suspected soft tissue sarcoma, alongside a review of the literature.

CT imaging for evaluation of calcium crystal deposition in the knee: initial experience from the Multicenter Osteoarthritis (MOST) study

OBJECTIVE

Role of intra-articular calcium crystals in osteoarthritis (OA) is unclear. Imaging modalities used to date for its evaluation have limitations in their ability to fully characterize intra-articular crystal deposition. Since Computed Tomography (CT) imaging provides excellent visualization of bones and calcified tissue, in this pilot project we evaluated the utility of CT scan in describing intra-articular calcium crystal deposition in the knees.

METHOD

We included 12 subjects with and four subjects without radiographic chondrocalcinosis in the most recent visit from the Multicenter Osteoarthritis (MOST) study, which is a longitudinal cohort of community-dwelling older adults with or at risk for knee OA. All subjects underwent CT scans of bilateral knees. Each knee was divided into 25 subregions and each subregion was read for presence of calcium crystals by a musculoskeletal radiologist. To assess reliability, readings were repeated 4 weeks later.

RESULTS

CT images permitted visualization of 25 subregions with calcification within and around the tibio-femoral and patello-femoral joints in all 24 knees with radiographic chondrocalcinosis. Intra-articular calcification was seen universally including meniscal cartilage (most common site involved in 21/24 knees), hyaline cartilage, cruciate ligaments, medial collateral ligament and joint capsule. Readings showed good agreement for specific tissues involved with calcium deposition (kappa: 0.70, 95% CI 0.62-0.80).

CONCLUSION

We found CT scan to be a useful and reliable tool for describing calcium crystal deposition in the knee and therefore potentially for studying role of calcium crystals in OA. We also confirmed that "chondrocalcinosis" is a misnomer because calcification is present ubiquitously.

Applications of dual-energy CT in emergency radiology

OBJECTIVE

Recent technologic advances in MDCT have led to the introduction of dual-energy CT (DECT). The basic principle of DECT is to acquire images at two different energy levels simultaneously and to use the attenuation differences at these different energy levels for deriving additional information, such as virtual monochromatic images, artifact suppression, and material composition of various tissues.

CONCLUSION

A variety of image reconstruction and postprocessing techniques are available for better demonstration and characterization of pathologic abnormalities. DECT can provide both anatomic and functional information of different organ systems. This article focuses on the main applications of DECT in emergency radiology.

Peering through the glare: using dual-energy CT to overcome the problem of metal artefacts in bone radiology

OBJECTIVE

Imaging of patients with large metal implants remains one of the most difficult endeavours for radiologists. This article reviews the theory of dual-energy CT (DECT) and its ability to reduce metal artefact, thus enhancing the diagnostic value of musculoskeletal imaging. The strengths, weaknesses, and alternative applications of DECT, as well as areas requiring further research, will also be reviewed.

CONCLUSION

Currently, DECT stands as the frontier for metal artefact reduction in musculoskeletal imaging. DECT requires no additional radiation and provides significantly enhanced image acquisition. When considered along with its other capabilities, DECT is a promising new tool for musculoskeletal and trauma radiologists.

Tumoral Calcinosis Form of Hydroxyapatite Deposition Disease in Related Red-Bellied Short-Necked Turtles, Emydura subglobosa

Ten of 12 red-bellied short-necked turtles from a single clutch presented at 9 months of age with multiple white to tan nodules on their feet. Histologically, the nodules were composed of large periarticular deposits of mineralized crystalline material that extended into the joint spaces of interphalangeal joints and was surrounded by granulomatous inflammation and fibrosis. Crystallographic analysis determined the material to be apatite (calcium phosphate hydroxide) consistent with the tumoral calcinosis form of hydroxyapatite deposition disease (HADD). HADD has previously been described in aquatic turtles and rarely lizards and must be differentiated from gout in reptiles. A cause for the tumoral calcinosis lesions in these turtles could not be determined; however, based on previous reports in this species, a species-specific predilection, in conjunction with unknown environmental factors, is suspected. The use of the terms HADD, pseudogout (calcium pyrophosphate crystal deposition disease), and calcinosis circumscripta has been inconsistent, creating confusion in the literature.

Dual-energy CT: a promising new technique for assessment of the musculoskeletal system

OBJECTIVE

Dual-energy CT (DECT) characterizes the chemical composition of material according to its differential x-ray attenuation at two different energy levels. Applications of DECT in musculoskeletal imaging include imaging of bone marrow edema, tendons, and ligaments and the use of monoenergetic techniques to minimize metal prosthesis beam-attenuating artifacts.

CONCLUSION

The most validated application of DECT is undoubtedly its noninvasive and highly specific ability for confirming the presence of monosodium urate deposits in the assessment of gout.

Dual energy CT in gout: a prospective validation study

OBJECTIVE

The authors prospectively determined: (1) the specificity and sensitivity of dual energy CT (DECT) for gout; and (2) the interobserver and intraobserver reproducibility for DECT urate volume measurements.

METHODS

Forty crystal-proven gout patients (17 tophaceous) and 40 controls with other arthritic conditions prospectively underwent DECT scans of all peripheral joints using a gout protocol that color-codes the composition of tissues. A blinded radiologist identified urate deposition to calculate specificity and sensitivity of DECT for gout. Inter-rater volumetric reproducibility was determined by two independent radiologists on 40 index tophi from the 17 tophaceous gout patients using automated software.

RESULTS

The mean age of the 40 gout patients was 62 years, the mean gout duration was 13 years and 87% had a history of urate-lowering therapy (ULT). The specificity and sensitivity of DECT for gout were 0.93 (95% CI, 0.80 to 0.98) and 0.78 (0.62 to 0.89), respectively. When the authors excluded three gout cases with unreadable or incomplete scans, the sensitivity was 0.84 (95% CI, 0.68 to 0.94). The urate volumes of 40 index tophi ranged from 0.06 cm(3) to 18.74 cm(3) with a mean of 2.45 cm(3). Interobserver and intraobserver intraclass correlation coefficients for DECT volume measurements were 1.00 (95% CI, 1.00 to 1.00) and 1.00 (95% CI, 1.00 to 1.00) with corresponding bias estimates (SD) of 0.01 (0.00) cm(3) and 0.01 (0.03) cm(3).

CONCLUSIONS

These prospective data indicate high reproducibility of DECT urate volume measures. The specificity was high, but sensitivity was more moderate, potentially due to frequent ULT use in our patients.

A re-look at an old disease: a multimodality review on gout

Gout, the most common form of microcrystalline arthropathy has always interested radiologists. The diagnosis of gout is primarily based on clinical and laboratory findings; however, it has well known and characteristic radiographic manifestations. Radiographs remain the examination of choice in the diagnosis of joint involvement. Plain radiographs are less sensitive to early changes in gout than other imaging techniques. Recently, magnetic resonance imaging (MRI), ultrasound (US), and computed tomography (CT) have demonstrated an increasing role in early diagnosis of gouty arthritis, for assessing the extent of soft-tissue involvement and as problem-solving tools for diagnostically difficult cases. Cross-sectional imaging can also be used for guiding needle aspirations in patients with an acute attack of gout, which may simulate an infective process clinically. This pictorial review illustrates the main imaging features of gout on radiographs, MRI, CT, and ultrasound with the aim of helping the radiologist to make a confident diagnosis in radiographically typical cases and to serve as a problem-solving tool in cases that present a diagnostic dilemma.

Magnetic resonance imaging of inflammatory arthropathies of peripheral joints

As the treatment of inflammatory arthropathies has advanced with new therapies that can slow or even halt the development of disabling disease, early and accurate diagnosis has become imperative. Magnetic resonance (MR) imaging has proved to be very sensitive in the detection of erosions, but more importantly, it can demonstrate pre-erosive changes. Detection of synovitis and edema-like bone marrow lesions for initial diagnosis and as an indicator of disease progression can provide crucial information leading to therapeutic interventions before permanent joint damage occurs. Understanding the characteristic intra-articular and extra-articular MR imaging findings of the inflammatory arthritides allows the radiologist to provide appropriate consultations in the care of these patients. The MR appearances of both intra-articular and extra-articular findings of inflammatory arthritis are presented. Despite the advances in imaging, however, many of the MR findings remain nonspecific, and radiologists must avoid overdiagnosis by synthesizing all of the clinical information available into their interpretations.

Inflammatory and oxidative stress markers in experimental crystalopathy: their modification by photostimulation

Crystalopathies are inflammatory pathologies caused by cellular reactions to the deposition of crystals in the joints. The anti-inflammatory effect of the helium-neon (He-Ne) laser and that of the nonsteroidal anti-inflammatory drugs (NSAIDs) diclofenac, meloxicam, celecoxib, and rofecoxib was studied in acute and chronic arthritis produced by hydroxyapatite and calcium pyrophosphate in rats. The presence of the markers fibrinogen, L-citrulline, nitric oxide, and nitrotyrosine was determined. Crystals were injected into the posterior limb joints of the rats. A dose of 8 J/cm(2) of energy from an He-Ne laser was applied for 3 d in some groups and for 5 d in other groups. The levels of some of the biomarkers were determined by spectrophotometry, and that of nitrotyrosine was determined by ELISA. For statistical analysis, Fisher's exact test was used, and p +/- 0.05 was considered significant. In arthritic rats, the fibrinogen, L-citrulline, nitric oxide, and nitrotyrosine levels increased in comparison to controls and to the laser-treated arthritic groups (p +/- 0.001), (p +/- 0.001), (p +/- 0.02), and (p +/- 0.01), respectively. When comparing fibrinogen from arthritic rats with disease induced by hydroxyapatite with undiseased and arthritic rats treated with NSAIDs, the He-Ne laser decreased levels to values similar to those seen in controls (p +/- 0.01). Inflammatory and oxidative stress markers in experimental crystalopathy are positively modified by photobiostimulation.

Helium-neon laser reduces the inflammatory process of arthritis

OBJECTIVE

A histological study of the anti-inflammatory effect of helium-neon laser in models of arthropathies induced by hydroxyapatite and calcium pyrophosphate in rats.

BACKGROUND

Crystal deposition diseases are inflammatory pathologies induced by cellular reaction to the deposit of crystals in the joints.

METHODS

Fifty-six Suquia strain rats were distributed in seven groups. Two mg of each crystal diluted in 0.05 ml physiologic solution were injected six times in each back limb joint, during two weeks on alternate days. Eight J/cm(2) were applied daily to the crystal-injected joints on five consecutive days. The joints were cut and put in 10% formaldehyde, stained with hematoxylin-eosin and observed by light microscopy. The percentage of area with inflammatory infiltrates was determined in five optical microscopy photographs (100X) for each group and analyzed using the Axionvision 4.6 program. A Pearson's Chi Squared test was applied, with significance level set at p < 0.05.

RESULTS

Both crystals produced an inflammatory process in the osteoarticular structures, consisting of predominantly mononuclear infiltration, fibrosis, and granulomas of foreign body-type giant cells containing phagocytosed remains of crystals. In the arthritic joints treated with laser, a marked decrease (p < 0.0001) was found in the percentage of area with inflammatory infiltrates, although the granulomas remained in a less ostensible form, with adipose tissue cells, fibrosis bands with light residual inflammation, and an absence of or very few crystals. Laser alone or physiologic solution injection did not produce histological changes.

CONCLUSIONS

Helium-neon laser reduced the intensity of the inflammatory process in the arthritis model induced by hydroxyapatite and calcium pyrophosphate crystals.

Calcium pyrophosphate dihydrate crystal deposition disease: sonographic findings

High-resolution sonography is a rapidly evolving technique that is gaining an increasing success in the assessment of crystalline arthropathies. In calcium pyrophosphate dihydrate crystal deposition disease, the sonographic features of crystal deposition include hyperchoic spots within hyaline cartilage and/or fibrocartilage and soft tissue calcifications. The aim of this pictorial essay was to present the main findings evocative of crystal deposition in patients with pyrophosphate arthropathy.

[Diagnosis and treatment of calcium pyrophosphate crystal-induced arthropathy]

Calcium pyrophosphate dihydrate deposition (CPPDD) disease is the term used to describe a group of common and potentially severe metabolic arthropathies. In these, CPPD crystals form and are deposited in the cartilage matrix (chondrocalcinosis) and induce inflammatory and/or destructive mechanisms. Most cases are idiopathic, but hyperparathyroidism, hemochromatosis, hypomagnesemia and hypophosphatemia can promote or cause chondrocalcinosis. Early disease (with onset before the age of 60 years) thus requires that the patient be examined for these metabolic conditions, particularly hemochromatosis. The prevalence of CPPDD disease in the general population increases with age, being 10-15% in the age group 65-75 years and more than 40% in the over-80s. Although frequently asymptomatic, chondrocalcinosis can involve severe acute attacks of inflammatory arthritis (pseudogout) and also various types of chronic arthropathy including pseudorheumatoid arthritis, pseudo-osteoarthritis, and pseudoneuropathic joint disease. CPPD crystals can also be deposited in the bursae, ligaments, and tendons and generate inflammation and/or ruptures. The diagnosis is based on synovial fluid analysis (positively birefringent CPPD crystals visualized by compensated polarized light microscopy) and X-rays (punctate and linear radiodense areas in fibrocartilage and hyaline cartilage). Treatment is primarily symptomatic, since there is no known drug that can prevent progression of the joint destruction). Nonsteroid anti-inflammatory drugs (NSAIDs) and intra-articular or systemic glucocorticoids (amounts must be only small if use is prolonged) are the most useful treatments. Colchicine can be effective in recurring pseudogout, and magnesium can be used prophylactically. In a small uncontrolled series methotrexate was effective and aroused interest; it can be used when other treatments fail.

Detection of calcium phosphate crystals in the joint fluid of patients with osteoarthritis - analytical approaches and challenges

Clinically, osteoarthritis (OA) is characterised by joint pain, stiffness after immobility, limitation of movement and, in many cases, the presence of basic calcium phosphate (BCP) crystals in the joint fluid. The detection of BCP crystals in the synovial fluid of patients with OA is fraught with challenges due to the submicroscopic size of BCP, the complex nature of the matrix in which they are found and the fact that other crystals can co-exist with them in cases of mixed pathology. Routine analysis of joint crystals still relies almost exclusively on the use of optical microscopy, which has limited applicability for BCP crystal identification due to limited resolution and the inherent subjectivity of the technique. The purpose of this Critical Review is to present an overview of some of the main analytical tools employed in the detection of BCP to date and the potential of emerging technologies such as atomic force microscopy (AFM) and Raman microspectroscopy for this purpose.