Matteo Revelli

REAL-TIME ELASTOGRAPHY IN THE ASSESSMENT OF LIVER FIBROSIS: A REVIEW OF QUALITATIVE AND SEMI-QUANTITATIVE METHODS FOR ELASTOGRAM ANALYSIS

Despite its invasiveness, liver biopsy is still considered the gold standard for the assessment of hepatic fibrosis. Non-invasive ultrasound-based techniques are increasingly employed to assess parenchymal stiffness and the progression of chronic diffuse liver diseases. Real-time elastography is a rapidly evolving technique that can reveal the elastic properties of tissues. This review examines qualitative and semi-quantitative methods developed for analysis of real-time liver elastograms, to estimate parenchymal stiffness and, indirectly, the stage of fibrosis. Qualitative analysis is the most immediate approach for elastogram analysis, but this method increases intra- and inter-observer variability, which is seen as a major limitation of real-time elastography. Semi-quantitative methods include analysis of the histogram derived from color-coded maps, as well as calculation of the elastic ratio and fibrosis index.

Seronegative Spondyloarthropathies: what radiologists should know.

Inflammatory involvement of the spine and sacroiliac joints is the most peculiar feature of seronegative spondyloarthropathies (SpA), which include ankylosing spondylitis, psoriatic arthritis, reactive arthritis (Reiter’s syndrome), enteropathic spondylitis (related to inflammatory bowel diseases) and undifferentiated spondyloarthropathies. SAPHO syndrome may also be considered a SpA, but there is no clear agreement in this respect. Imaging, along with clinical and laboratory evaluation, is an important tool to reach a correct diagnosis and to provide a precise grading of disease progression, influencing both clinical management and therapy. Conventional radiography, which is often the first-step imaging modality in SpA, does not allow an early diagnosis. Computed tomography (CT) demonstrates with a very high spatial resolution the tiny structural alterations of cortical and spongy bone before they become evident on plain film radiographs. Magnetic resonance imaging (MRI) is the only modality that provides demonstration of bone marrow oedema, which reflects vasodilatation and inflammatory hyperaemia. The primary aim of this review article was to examine the involvement of the spine and sacroiliac joints in SpA using a multimodal radiological approach (radiography, CT, MRI), providing a practical guide for the differential diagnosis of these conditions.

Multimodality imaging of intraosseous ganglia of the wrist and their differential diagnosis

Intraosseous ganglion (IOG) is the most frequently occurring bone lesion within the carpus and is often an incidental finding on radiographs obtained for other reasons. Two types of IOG have been described: an “idiopathic” form (or type I), the pathogenesis of which has not been completely clarified, and a “penetrating” form (or type II), caused by the intrusion of juxtacortical material (often a ganglion cyst of the dorsal soft tissue) into the cancellous bone compartment. The differential diagnosis for IOG is wide-ranging and complex, including lesions of posttraumatic (posttraumatic cystlike defects), degenerative (subchondral degenerative cysts), inflammatory [cystic rheumatoid arthritis, chronic tophaceous gout (CTG)], neoplastic (benign primary bone tumours and synovial proliferative lesions), ischaemic (Kienböck’s disease or avascular osteonecrosis of the lunate) and metabolic (amyloidosis) origin. Multimodality imaging of IOGs is a useful diagnostic tool that provides complete morphological characterisation and differentiation from other intraosseous cystic abnormalities of the carpus. Thin-slice multidetector computed tomography (MDCT) can provide high-spatial-resolution images of the cortical and cancellous bone compartments, allowing detection of morphological findings helpful in characterising bone lesions, whereas magnetic resonance (MR) imaging can simultaneously visualise bone, articular surfaces, hyaline cartilage, fibrocartilage, capsules and ligaments, along with intra- and periarticular soft tissues.RiassuntoIl ganglio intraosseo (IOG) è la lesione ossea del carpo di più frequente riscontro e spesso rappresenta un reperto occasionale in esami radiografici eseguiti per altri motivi. I IOG vengono distinti in due forme: la forma idiopatica (o tipo I), la cui patogenesi non è stata ancora completamente chiarita, e quella penetrante (o tipo II), determinata dall’intrusione nel compartimento spongioso di materiale juxtacorticale, spesso rappresentato da un ganglio dei tessuti molli dorsali del carpo. La diagnosi differenziale dei IOG è ampia ed articolata, includendo lesioni di origine post-traumatica (difetti simil-cistici post-traumatici, PTCD), degenerativa (cisti subcondrali degenerative, SDC), infiammatoria (artrite reumatoide cistica e gotta cronica tofacea), neoplastica (tumori ossei primitivi e lesioni proliferative sinoviali benigne), ischemica (morbo di Kienbock od osteonecrosi avascolare del semilunare) e metabolica (amiloidosi). L’imaging integrato dei IOG è fondamentale per la loro completa caratterizzazione morfologica e per distinguerli dalle altre lesioni pseudocistiche intraspongiose che si possono sviluppare nelle ossa del carpo. La tomografia computerizzata multi-detettore (MDCT) consente di ottenere immagini ad elevata risoluzione spaziale dei compartimenti ossei corticale e spongioso, permettendo di rilevare elementi morfologici utili ad una precisa caratterizzazione delle lesioni ossee, mentre la risonanza magnetica (RM) offre il vantaggio di visualizzare simultaneamente la componente ossea, le superfici articolari, gli spessori condrali, le strutture fibrocartilaginee, capsulo-legamentose ed i tessuti molli intra- e peri-articolari.

Diagnostic Value of MRI Proton Density Fat Fraction for Assessing Liver Steatosis in Chronic Viral C Hepatitis

Objective. To assess the diagnostic performance of a T1-independent, T2*-corrected multiecho magnetic resonance imaging (MRI) technique for the quantification of hepatic steatosis in a cohort of patients affected by chronic viral C hepatitis, using liver biopsy as gold standard. Methods. Eighty-one untreated patients with chronic viral C hepatitis were prospectively enrolled. All included patients underwent MRI, transient elastography, and liver biopsy within a time interval <10 days. Results. Our cohort of 77 patients included 43/77 (55.8%) males and 34/77 (44.2%) females with a mean age of 51.31 ± 11.27 (18–81) years. The median MRI PDFF showed a strong correlation with the histological fat fraction (FF) (r = 0.754, 95% CI 0.637 to 0.836, P < 0.0001), and the correlation was influenced by neither the liver stiffness nor the T2* decay. The median MRI PDFF result was significantly lower in the F4 subgroup (P < 0.05). The diagnostic accuracy of MRI PDFF evaluated by AUC-ROC analysis was 0.926 (95% CI 0.843 to 0.973) for S ≥ 1 and 0.929 (95% CI 0.847 to 0.975) for S = 2. Conclusions. Our MRI technique of PDFF estimation allowed discriminating with a good diagnostic accuracy between different grades of hepatic steatosis.

Crohn's disease recurrence in patients with ileocolic anastomosis: Value of computed tomography enterography with water enema

OBJECTIVES The main objective of the present work was to determine the diagnostic value of CT-enterography with water enema (CTe-WE) in the assessment of the ileocolic anastomosis in patients with Crohns disease (CD). The prevalence of synchronous inflammatory lesions (SILs) involving gastrointestinal segments distinct from the anastomosis was also determined. Further, the association between the type of ileocolic anastomosis and the behavior (i.e. inflammatory, stricturing, penetrating) of CD recurrence was evaluated. METHODS 51 patients were retrospectively included (26 [51%] male and 25 [49%] female; mean age: 52.88 years ± 13.35). Ileocolic anastomoses were: 18 (35.3%) stapled side-to-side, 17 (33.3%) end-to-side, and 16 (31.4%) end-to-end. CTe-WEs were reviewed in consensus by two gastrointestinal radiologists. Endoscopy and medical records were used as reference standards. RESULTS CTe-WE yielded 95.35% sensitivity (CI 95%: 84.19-99.43%), 75.00% specificity (CI 95%: 34.91-96.81%), and 92.15% diagnostic accuracy (CI 95%: 81.31-98.02%). Anastomotic recurrence was found in 41/51 (80.4%) patients, including 30/41 (73.2%) cases of isolated anastomotic recurrence, and 11/41 (26.8%) cases of anastomotic recurrence with a SIL. A significant lower prevalence of stricturing recurrence was observed in patients with stapled side-to-side anastomoses (p=0.033). CONCLUSIONS CTe-WE provides a good distension of both sides of ileocolic anastomoses allowing the detection of SILs.

Optimal management of constipation associated with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common chronic functional disorder of the gastrointestinal tract, meanly characterized by recurrent abdominal pain or discomfort and altered bowel habit. It is a complex disorder involving biological, environmental, and psychosocial factors. The diagnosis is achieved according to the Rome III criteria provided that organic causes have been excluded. Although IBS does not constitute a life-threatening condition, it has a remarkable prevalence and profoundly reduces the quality of life with burdening socioeconomic costs. One of the principal concerns about IBS is the lack of effective therapeutic options. Up to 40% of patients are not satisfied with any available medications, especially those suffering from chronic constipation. A correct management of IBS with constipation should evolve through a global approach focused on the patient, starting with careful history taking in order to assess the presence of organic diseases that might trigger the disorder. Therefore, the second step is to examine lifestyle, dietary habits, and psychological status. On these bases, a step-up management of disease is recommended: from fiber and bulking agents, to osmotic laxative drugs, to new molecules like lubiprostone and linaclotide. Although new promising tools for relief of bowel-movement-related symptoms are being discovered, a dedicated doctor–patient relationship still seems to be the key for success.

Imaging studies of crystalline arthritides

Gout, calcium pyrophosphate dihydrate (CPPD) deposition disease, and calcium hydroxyapatite deposition disease (HADD) are the three most common crystal-induced arthropathies. Multimodality imaging may help in their diagnosis, and is useful for a precise and comprehensive assessment and grading of the related osteoarticular damage. Plain film radiography, due to its low cost and wide availability, is the first imaging technique to be used in crystal deposition diseases, providing well-known and specific findings for CPPD deposition disease and HADD, while it may undergrade the early osteoarticular lesions in gouty patients. Ultrasonography (US) is a radiation-free approach that accurately depicts crystal deposits in cartilage, peri- and intra-articular soft tissues, but it does not give a panoramic view of the affected joints. Cross-sectional imaging techniques can examine crystal deposits in the spine and axial joints. CT has the potential to distinguish monosodium urate (MSU) crystals from calcium containing crystals, due to their different attenuation values. MRI may demonstrate synovitis, erosions and bone marrow edema in gouty patients and it may differentiate tophi from other soft tissue nodules due to its high contrast resolution and power of tissue characterization.

Degree of colonic distension: intrapatient comparison between CT colonography and CT with water enema.

PURPOSE Compare colonic distension using CT colonography (CTC) and CT with water enema (CTWE) in the same patients. METHODS AND MATERIALS Twenty-seven patients who underwent both CTC and CTWE, considering separately supine (CTC-S) and prone (CTC-P) acquisition of CTC were included. The colon was divided into six segments, performing both a qualitative and quantitative analysis. RESULTS Adequate distension of sigmoid colon was more frequently achieved with CTC-P and CTWE compared to CTC-S (P<.05). CTC-P and CTWE showed better distension of the left colon compared to CTC-S (P<.01 and P=.03 regarding sigmoid colon, respectively; P=.01 and P=.03 regarding descending colon, respectively). CONCLUSIONS Computed tomography (CT) studies of the colon should be customized to fulfill the clinical query.

Role of respiratory-triggered diffusion-weighted MRI in the assessment of pleural disease

OBJECTIVE: To evaluate the correlation between apparent diffusion coefficient (ADC) values and histopathological features in a cohort of patients with suspected malignant pleural disease. METHODS: We evaluated 56 consecutive patients undergoing a chest MRI examination for clinical suspicion of malignant pleural disease; all patients underwent thoracoscopic biopsy for histological assessment. All MRI examinations were performed with a 1.5-T scanner using a dedicated protocol, including a respiratory-triggered diffusion-weighted sequence with three b-values (0, 100 and 750). The ADC values were calculated, and a statistical analysis was performed. RESULTS: The average ADC value in non-neoplastic pleural disease (NNPD) resulted in 1.84 ± 0.37 × 10-3 mm2 s-1, whereas we obtained an average value of 0.96 ± 0.19 × 10-3 mm2 s-1 in epitheliod, of 0.76 ± 0.33 × 10-3 mm2 s-1 in biphasic and of 0.67 ± 0.2 × 10-3 mm2 s-1 in sarcomatoid pleural mesotheliomas. Histology revealed the presence of malignant pleural mesothelioma (MPM) in 44 patients, chronic pleuritis in 8 patients and atypical mesothelial hyperplasia in 4 patients. Statistical analysis showed a significant difference between NNPD and MPM (p < 0.001) and between epithelioid and sarcomatoid MPM subtypes (p = 0.0004), whereas biphasic MPMs showed a wide range of overlapping with the other groups. CONCLUSION: We observed a statistically significant difference between NNPD, epitheliod and sarcomatoid subtypes of MPM regarding ADC values. ADVANCES IN KNOWLEDGE: Our study confirmed previous data regarding distribution of ADC values in pleural disease using a respiratory-triggered diffusion-weighted technique that allowed us to minimize motion artefacts and to reduct acquisition time.

Multimodal imaging in the differential diagnosis of soft tissue calcinosis

Soft tissue calcinosis is a common radiographic finding, which may be related to different types of pathological processes. Multimodality imaging, combined with analysis of clinical and laboratory data, plays an important role for the differential diagnosis of these conditions. Conventional radiography is considered the first line approach to soft tissue calcinosis; CT and MRI may provide further information to better characterize calcified deposits. Imaging may help to distinguish metabolic calcification, such as primary tumoral calcinosis and the secondary one (associated with acquired disorders of calcium or phosphate regulation), from dystrophic calcification, which is associated to normal blood values of phosphate. The sedimentation sign typical of tumoral calcinosis has been demonstrated by plain film radiography, CT, MRI, and, more recently, by ultrasonography. Other types of soft tissue calcinosis may have a degenerative, metaplastic or neoplastic origin, and their characterization strongly relies on multimodality imaging.