Imaging of primary and secondary inflammatory diseases involving large and medium-sized vessels and their potential mimics: a multitechnique approach

Imaging of intestinal vasculitis focusing on MR and CT enterography: a two-way street between radiologic findings and clinical data

Diagnosis of intestinal vasculitis is often challenging due to the non-specific clinical and imaging findings. Vasculitides with gastrointestinal (GI) manifestations are rare, but their diagnosis holds immense significance as late or missed recognition can result in high mortality rates. Given the resemblance of radiologic findings with some other entities, GI vasculitis is often overlooked on small bowel studies done using computed tomography/magnetic resonance enterography (CTE/MRE). Hereon, we reviewed radiologic findings of vasculitis with gastrointestinal involvement on CTE and MRE. The variety of findings on MRE/CTE depend upon the size of the involved vessels. Signs of intestinal ischemia, e.g., mural thickening, submucosal edema, mural hyperenhancement, and restricted diffusion on diffusion-weighted imaging, are common in intestinal vasculitis. Involvement of the abdominal aorta and the major visceral arteries is presented as concentric mural thickening, transmural calcification, luminal stenosis, occlusion, aneurysmal changes, and collateral vessels. Such findings can be observed particularly in large- and medium-vessel vasculitis. The presence of extra-intestinal findings, including within the liver, kidneys, or spleen in the form of focal areas of infarction or heterogeneous enhancement due to microvascular involvement, can be another radiologic clue in diagnosis of vasculitis. The link between the clinical/laboratory findings and MRE/CTE abnormalities needs to be corresponded when it comes to the diagnosis of intestinal vasculitis.

Large Vessel Vasculitis as an Initial Manifestation of Acute Myeloid Leukemia: A Case Report

Large vessel vasculitis is characterized by chronic inflammation within the aortic wall and its major branches. The inflammation is considered to occur as a result of immune dysregulation. Hematologic malignancy is one of the rare causes of secondary vasculitis. Herein, we report a rare case of large vessel vasculitis associated with acute myeloid leukemia mimicking primary vasculitis.

Imaging of Cardiopulmonary Involvement in Systemic Immune-mediated Diseases: A Comprehensive Review

Systemic immune-mediated diseases (SID) are a large group of disorders characterized by complex inflammatory and autoimmune damage to various organs and tissues. Among the possible manifestations, SIDs may potentially involve each structure of the cardiopulmonary system. Each disease is characterized by a specific clinical presentation. Coronary artery disease, myocarditis, pericarditis, valvular disease, pulmonary arterial hypertension, and interstitial lung disease represent characteristic findings of cardiopulmonary involvement in these disorders and their prompt recognition is crucial for the diagnosis of SIDs and the patient's prognosis. In this setting, chest high-resolution computed tomography and cardiac magnetic resonance are the most important noninvasive techniques for the assessment of these diseases and their complications. The knowledge of various cardiac and pulmonary radiologic patterns increases the likelihood of diagnosing these disorders and can lead to improved understanding of the underlying pathophysiology to personalize the treatment for each patient.

Monitoring Disease Activity in Patients with Aortitis and Chronic Periaortitis Undergoing Immunosuppressive Therapy by Perfusion CT

RATIONALE AND OBJECTIVES

To evaluate the role of perfusion CT for monitoring inflammatory activity in patients with aortitis and chronic periaortitis undergoing immunosuppressive therapy.

MATERIALS AND METHODS

Seventeen symptomatic patients (median age 68.5 years) who underwent perfusion-based computed tomography (CT) monitoring after diagnostic contrast-enhanced CT were retrospectively included in this study. Blood flow (BF), blood volume (BV), volume transfer constant (k-trans), time to peak, and mean transit time were determined by setting circular regions of interest in prominently thickened parts of the vessel wall or perfused surrounding tissue at sites where the perfusion CT color maps showed a maximum BF value. Differences in CT perfusion and, morphological parameters, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were tested for significance during therapy.

RESULTS

In all patients BF and BV dropped at second perfusion CT (P < 0.05). In aortitis patients, CRP dropped from 3.86 ± 5.31 mg/dL to 0.9 ± 1.37 mg/dL and in periaortitis patients from 1.78 ± 2.25 mg/dL to 0.79 ± 1.55 mg/dL, whereas ESR dropped from 45.71 ± 37.59 seconds to 8.57 ± 3.1 seconds and 36.78 ± 34.67 seconds to 17.22 ± 21.82 seconds in aortitis and in periaortitis, respectively.

CONCLUSIONS

The course of perfusion CT parameters in aortitis and chronic periaortitis undergoing immunosuppressive therapy dropped at different extent after therapy.

The Utility of MRI in the Diagnosis of Takayasu Arteritis

Takayasu Arteritis (TA) is an inflammatory disorder involving the thoracoabdominal aorta and its branches and the pulmonary arteries, with eventual vascular stenosis, occlusion, or aneurysm formation. Conventional angiography has been the reference imaging standard for diagnosis of TA. The purpose of this case report is to demonstrate the utility of MR imaging and MR angiography in the diagnosis of Takayasu Arteritis in a pediatric patient. The patient is a 15-year-old female patient presenting with anemia, hypertension, and acute kidney injury. Initial chest CT demonstrated ectasia of the ascending and focal stenosis of the descending thoracic aorta, prompting further evaluation with MRI and MRA. MRI/MRA demonstrated mural thickening with luminal stenosis of the aorta and aortic branch vessels. These imaging findings were suggestive of a large vessel arteritis and along with the clinical presentation and laboratory abnormalities the diagnosis of Takayasu Arteritis was suggested. Several case series in adults have described the cross-sectional findings of TA. However, this case report demonstrates the utility of MRI/MRA in the evaluation of TA in children and in the course of follow-up, as it provides a noninvasive method for evaluating a child without ionizing radiation or iodinated contrast.

MRI parametric monitoring of biological therapies in primary large vessel vasculitides: a pilot study

OBJECTIVE

To evaluate the development of characteristic MRI changes in patients with primary large-vessel vasculitis (LVV) when treated with biological therapies.

METHODS

12 patients with primary LVV (8 patients with Takayasu arteritis and 4 patients with giant-cell arteritis) received biological therapy with tumour necrosis factor-α blockers (n = 9) or an interleukin-6 inhibitor (n = 3). MRI investigations were performed at baseline (pre-treatment) and follow-up. All patients underwent the same MRI/MR angiography (MRA) protocol. Laboratory parameters (C-reactive protein and erythrocyte sedimentation rate) and clinical response (Birmingham Vasculitis Activity Score) were assessed.

RESULTS

Wall thickness was 4.2 ± 0.3 mm pre-treatment and significantly decreased to 3.2 ± 0.3 mm post treatment in 9/12 patients. Mural enhancement was increased in all 12/12 patients with LVV, and subsided with therapy in 5/12 patients. Mural oedema or ill-defined contour were less prevalent but also improved with biological treatment. C-reactive protein and erythrocyte sedimentation rate levels decreased, and clinical assessment revealed a significant improvement from pre-treatment to post-treatment. However, the course of imaging characteristics often did not parallel that of laboratory or clinical parameters. In all three patients receiving interleukin-6 blockade, laboratory markers and clinical scores normalized despite persistent vascular inflammation in one patient which was disclosed by MRI.

CONCLUSION

Contrast-enhanced MRI/MRA may be useful when evaluating the development of disease activity in primary LVV under biological therapies. A high degree of suspicion and regular imaging follow-up is needed to detect persistent inflammation.

ADVANCES IN KNOWLEDGE

This is the first study investigating the applicability of different MRI/MRA parameters for monitoring biological therapy in patients with primary LVV.

Imaging of systemic vasculitis in childhood

The term "systemic vasculitis" encompasses a diverse set of diseases linked by the presence of blood-vessel inflammation that are often associated with critical complications. These diseases are uncommon in childhood and are frequently subjected to a delayed diagnosis. Although the diagnosis and treatment may be similar for adult and childhood systemic vasculitides, the prevalence and classification vary according to the age group under investigation. For example, Kawasaki disease affects children while it is rarely encountered in adults. In 2006, the European League Against Rheumatism (EULAR) and the Pediatric Rheumatology European Society (PReS) proposed a classification system for childhood vasculitis adopting the system devised in the Chapel Hill Consensus Conference in 1993, which categorizes vasculitides according to the predominant size of the involved blood vessels into small, medium and large vessel diseases. Currently, medical imaging has a pivotal role in the diagnosis of vasculitis given recent developments in the imaging of blood vessels. For example, early diagnosis of coronary artery aneurysms, a serious complication of Kawasaki disease, is now possible by magnetic resonance imaging (MRI) of the heart and multidetector computed tomography (MDCT); positron emission tomography/CT (PET/CT) helps to assess active vascular inflammation in Takayasu arteritis. Our review offers a unique approach using the integration of the proposed classification criteria for common systemic childhood vasculitides with their most frequent imaging findings, along with differential diagnoses and an algorithm for diagnosis based on common findings. It should help radiologists and clinicians reach an early diagnosis, therefore facilitating the ultimate goal of proper management of affected children.

[Diagnosis of large-vessel vasculitis using [18F]-FDG PET-CT]

PURPOSE

The aim of this retrospective study was to assess the performance of fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography ([(18)F]-FDG PET-CT) for diagnosing large-vessel vasculitis (LVV) for a subset of patients at increased risk of rheumatic/immune diseases, taking into account concurrent immunosuppressive therapy.

MATERIALS AND METHODS

The study comprised 64 rheumatological referrals with suspected LVV; half of the patients were on immunosuppressive therapy at the time of examination. The final diagnosis of LVV was established in 31 patients. To evaluate vascular uptake, the nuclear medicine physician employed both a semiquantitative method based on standardised uptake value (SUV) determination and a qualitative method based on a visual score from 0 to 3 on the maximum intensity projection (MIP) reformats. Finally, a joint assessment was carried out between the nuclear medicine physician and the reporting radiologist, in which PET metabolic data were re-evaluated taking into account clinical data and baseline CT scans. McNemar's test was used to compare four types of analysis: semiquantitative (cutoff ≥ 2.4), qualitative with standard cutoff (grade ≥ 2), qualitative with reduced cutoff (grade ≥ 1) and joint.

RESULTS

Semiquantitative analysis (sensitivity 74.19%, specificity 78.78%, accuracy 76.56%) and qualitative analysis with standard cutoff (sensitivity 64.51%, specificity 84.84%, accuracy 75.00%) showed no statistical difference for the diagnosis of LVV, whereas qualitative analysis with lower cutoff (sensitivity 93.54%, specificity 75.75%, accuracy 84.37%) proved to be better than the other two. Joint analysis (sensitivity 93.54%, specificity 93.93%, accuracy 93.75%) introduced some corrective elements not present in the qualitative analysis with cutoff ≥ 1 and therefore increased specificity significantly.

CONCLUSIONS

Interpretation of PET-CT should be individualised for each patient by taking into account clinical-radiological and metabolic data. To this end, cooperation between the nuclear medicine specialist and the radiologist is essential.

The impact of 18F-FDG PET on the management of patients with suspected large vessel vasculitis

PURPOSE

We aimed to assess the impact of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) on the management of patients with suspected large vessel vasculitis.

METHODS

An international expert panel determined diagnoses and clinical management in patients with suspected large vessel vasculitis, with and without the results of (18)F-FDG PET, respectively. The accuracy of the clinical diagnosis and the resulting clinical management with and without the (18)F-FDG PET results were compared using logistic regression models.

RESULTS

The analysis included 30 patients referred to a tertiary care centre with large vessel vasculitis and 31 controls. (18)F-FDG PET had an overall sensitivity of 73.3% [95% confidence interval (CI) 54.1-87.7%], a specificity of 83.9% (95% CI 66.3-94.5%), a positive predictive value of 81.5% (95% CI 61.9-93.7%) and a negative predictive value of 76.5% (95% CI 58.8-89.3%). The diagnostic accuracy of (18)F-FDG PET was higher in patients not receiving immunosuppressive drugs (93.3 vs 64.5%, p = 0.006). Taken in context with other available diagnostic modalities, the addition of (18)F-FDG PET increased the clinical diagnostic accuracy from 54.1 to 70.5% (p = 0.04). The addition of (18)F-FDG PET increased the number of indicated biopsies from 22 of 61 patients (36.1%) to 25 of 61 patients (41.0%) and changed the treatment recommendation in 8 of 30 patients (26.7%) not receiving immunosuppressive medication and in 7 of 31 patients (22.6%) receiving immunosuppressive medication.

CONCLUSION

(18)F-FDG PET is a sensitive and specific imaging tool for large vessel vasculitis, especially when performed in patients not receiving immunosuppressive drugs. It increases the overall diagnostic accuracy and has an impact on the clinical management in a significant proportion of patients.