Radiological differences between chronic thromboembolic pulmonary disease (CTEPD) and chronic thromboembolic pulmonary hypertension (CTEPH).

OBJECTIVES: The aim of this study was to describe the radiological features of chronic thromboembolic pulmonary disease (CTEPD), not yet systematically described in the literature. Furthermore, we compared vascular scores between CTEPD and chronic thromboembolic pulmonary hypertension (CTEPH) patients, trying to explain why pulmonary hypertension does not develop at rest in CTEPD patients. METHODS: Eighty-five patients (40 CTEPD, 45 CTEPH) referred to our centre for pulmonary endarterectomy underwent dual-energy computed tomography pulmonary angiography (DE-CTPA) with iodine perfusion maps; other 6 CTEPD patients underwent single-source CTPA. CT scans were reviewed independently by an experienced cardiothoracic radiologist and a radiology resident to evaluate scores of vascular obstruction, hypoperfusion and mosaic attenuation, signs of pulmonary hypertension and other CT features typical of CTEPH. RESULTS: Vascular obstruction burden was similar in the two groups (p = 0.073), but CTEPD patients have a smaller extension of perfusion defects in the iodine map (p = 0.009) and a smaller number of these patients had mosaic attenuation (p < 0.001) than CTEPH patients, suggesting the absence of microvascular disease. Furthermore, as expected, the two groups were significantly different considering the indirect signs of pulmonary hypertension (p < 0.001). CONCLUSIONS: CTEPD and CTEPH patients have significantly different radiological characteristics, in terms of signs of pulmonary hypertension, mosaic attenuation and iodine map perfusion extension. Importantly, our results suggest that the absence of peripheral microvascular disease, even in presence of an important thrombotic burden, might be the reason for the absence of pulmonary hypertension in CTEPD. KEY POINTS: • CTEPD and CTEPH patients have significantly different radiological characteristics. • The absence of peripheral microvascular disease might be the reason for the absence of pulmonary hypertension in CTEPD.

Role of cardiac magnetic resonance in the differential diagnosis between arrhythmogenic cardiomyopathy with left ventricular involvement and previous infectious myocarditis.

AIMS: Arrhythmogenic cardiomyopathy with left ventricular involvement (ACM-LV), particularly in case of isolated left ventricular involvement (i.e. left dominant arrhythmogenic cardiomyopathy, LDAC) and previous infectious myocarditis (pIM) may have overlapping clinical and cardiac magnetic resonance (CMR) features. To date, there are no validated CMR criteria for the differential diagnosis between these conditions. The present study aimed to identify CMR characteristics to distinguish ACM-LV from pIM. METHODS AND RESULTS: This observational, retrospective, single-centre study included 30 pIM patients and 30 ACM-LV patients. In ACM-LV patients CMR was performed at diagnosis; in patients with pIM, CMR was performed six months after acute infection. CMR analysis included quantitative assessment of left ventricle (LV) volumes, systolic function and wall thicknesses, qualitative and quantitative assessment of late gadolinium enhancement (LGE) sequences. Compared with pIM, ACM-LV patients showed slightly larger LV volumes, more frequent regional wall motion anomalies and reduced wall thicknesses. ACM-LV patients had higher amounts of LV LGE and extension. Notably, the LDAC subgroup had the highest amount of LV LGE. LV LGE amount > 15 g and a LV LGE percentage > 30% of LV mass discriminated ACM-LV from pIM with a 100% specificity. LGE segmental distribution was superimposable among the groups, except for septal segments that were more frequently involved in ACM-LV and LDAC patients. CONCLUSIONS: A great extension of LV LGE (a cut-off of LGE >15 g and a percentage above 30% of LV LGE in relation to total myocardial mass) discriminates ACM-LV from pIM with extremely high specificity.

Influence of subjects' characteristics and technical variables on muscle stiffness measured by shear wave elastosonography.

PURPOSE: The aim of this study is to quantitatively assess lower limbs muscle elasticity in a court of healthy subjects and to evaluate the influence of technical variables (e.g., diameter of the ROI-region of interest) and examined subjects' characteristics (e.g., sex, levels of physical activity, side evaluated) on muscle stiffness. MATERIALS AND METHODS: 54 healthy subjects (48 men, 6 women) were evaluated for a total of 108 lower limbs. Shear wave elastography was performed with a multifrequency linear probe (15-4 MHz). Two radiologists performed the evaluation of lower limbs from left to right side (first calf and then thigh). The measures were taken on gastrocnemius and on femoral biceps muscle belly. We chose to place for this study two ROIs of 4 and 2 mm of diameter. RESULTS: The mean muscle stiffness was 1.98 ± 0.48 (range between 1.89 ± 0.36 and 2.15 ± 0.57 m/s). The difference in muscle stiffness between left and right side of the body and between different levels of physical activity never became statistically significant (p value between 0.314 and 0.915). Only in one test out of eight the difference of muscle stiffness between male and female resulted statistically significant (p value 0.020). When comparing the measurement obtained with a 2 and 4 mm diameter ROIs the values were statistically different only for the left thigh (p value 0.028). CONCLUSION: Our study, despite its limitations (low sample and low female population), seems to give some clear advice: physiological or technical factors do not determine statistically significant differences on passive muscle stiffness.

Ultrasound-Guided Approach for L5 Dorsal Ramus Block and Fluoroscopic Evaluation in Unpreselected Cadavers.

BACKGROUND AND OBJECTIVES: Medial branch blocks are frequently performed to diagnose lumbar facet-joint-mediated pain. Ultrasound guidance can increase practicability and eliminate exposure to ionizing radiation when compared with fluoroscopy. However, ultrasound-guided L5 dorsal ramus block, which, together with L4 medial branch block is necessary to anesthetize the most commonly affected facet joint L5/S1, has not been described so far. The objective of this study was to develop a technique and to evaluate its accuracy with standard fluoroscopy in unpreselected cadavers. METHODS: Twenty ultrasound-guided L5 dorsal ramus block approaches were performed with a new oblique out-of-plane technique in a rotated cross-axis view bilaterally in 10 cadavers. After checking the needle position in a second perpendicular sonographic plane, the final needle position was confirmed with conventional fluoroscopy by an independent observer. RESULTS: All cadavers had significant degenerations of the lumbar spine, and 5 of them had moderate to severe spondylolisthesis. Skin-to-target distances were 42 ±7 mm. Sixteen L5 dorsal ramus block attempts were located at the exact radiological target, 1 was slightly too lateral, and 3 were slightly too caudal (3-10 mm away). The overall success rate in unpreselected cadavers reached 80% (95% confidence interval, 56%-94%) and in the subgroup of corpses without spondylolisthesis 100% (95% confidence interval, 69%-100%). CONCLUSIONS: This is the first study to show that ultrasound-guided L5 dorsal ramus block is accurate and feasible in the absence of significant spondylolisthesis when performed with an oblique out-of-plane technique.