Ultrasound and anatomical assessment of the infraspinatus tendon through anterosuperolateral approach.

OBJECTIVES: In the literature, shoulder ultrasound (US) protocols rely on the widely accepted anatomical concept of the infraspinatus tendon (IST) running parallel and posterior to the supraspinatus tendon (SST). To assess the IST, authors currently recommend placing the transducer posteroinferior to the acromion; however the examination of the anterosuperior part of the IST remains problematic. The aim of our study was to apply recent anatomical knowledge to propose a simple protocol to assess the IST over its entire width including its anterosuperior margin. MATERIALS AND METHODS: Six non-diseased shoulders from four cadavers were assessed in hyperextended internal rotation (HIR) position with US anterosuperolateral approach followed by dissection. Twelve healthy volunteers underwent similar US examination of the shoulder. RESULTS: The IST is a thin, wide, strap-like tendon. The HIR position exposed the largest area of IST beyond the acromion; combined anterosuperolateral US approach enabled imaging of the IST over its entire width with transverse and longitudinal views. The anterosuperior margin of the IST was distinguishable from the SST. CONCLUSION: The anterosuperolateral US approach in HIR position enables an accurate assessment of the IST including the transverse plane. The limit between the SST and IST appears more clearly. KEY POINTS: • The hyperextended internal rotation of the shoulder brings the infraspinatus tendon forward. • The infraspinatus tendon is visible with anterosuperolateral ultrasound approach. • The anterosuperior margin of the infraspinatus tendon is visible with this technique.

Single-source dual-energy CT angiography with reduced iodine load in patients referred for aortoiliofemoral evaluation before transcatheter aortic valve implantation: impact on image quality and radiation dose.

OBJECTIVES: To compare image quality and radiation dose of pre-transcatheter aortic valve implantation (TAVI) aortoiliofemoral CT angiography (AICTA) provided by standard vs. dual-energy mode with reduced iodine load protocols. METHODS: One hundred and sixty-one patients underwent a two-step CTA protocol before TAVI including cardiac CTA with injection of 65 mL of iodinated contrast agent (ICA), immediately followed by AICTA. From this second acquisition, the following three different patient groups were identified: Group 1: 52 patients with standard AICTA (60 mL ICA, 100 kVp, mA automodulation); Group 2: 48 patients with dual-energy AICTA with 50 % iodine load reduction (30 mL ICA, fast kVp switching, 600 mA); Group 3: 61 patients with an identical protocol to Group 2, but exposed to 375 mA. The qualitative/subjective image quality (13-point score) and quantitative/objective image quality (contrast attenuation and image noise) were evaluated. The radiation dose was recorded. RESULTS: There was no significant difference in non-diagnostic images between the three protocols. Contrast attenuation, signal-to-noise ratio and contrast-to-noise ratio were significantly higher, whereas noise was significantly lower in the standard protocol (all P < 0.05). The radiation dose was lower in the dual-energy protocol at 375 mA (P < 0.05). CONCLUSIONS: Dual-energy AICTA before TAVI results in a reduction of iodine load while maintaining sufficient diagnostic information despite increased noise. KEY POINTS: • Dual-energy AICTA before TAVI results in a 50 % reduction of iodine load. •The reduction of iodine load maintains sufficient image quality despite increased noise. • Using 375 mA in dual-energy mode results in a reduction of radiation dose. • A high tube current setting (600 mA) should be used in overweight patients.

Magnetic resonance anatomy of the superior part of the rotator cuff in normal shoulders, assessment and practical implication.

OBJECTIVES: The superior part of the rotator cuff consists of the anterior (SSa) and posterior (SSp) parts of the supraspinatus tendon, the infraspinatus (IS) tendon plus the articular capsule. An overlap of the distal SSp tendon by the anterior part of the IS one has been anatomically demonstrated; the insertion area of the IS is more anterior than currently believed. The aim of our study was to assess this complex architecture through standard MRI scans. METHODS: Twenty-five healthy volunteers underwent a shoulder MRI. Three planes T2 fat saturation sequences were read in consensus by two radiologists. The SSa, the SSp, the IS tendons and the articular capsule were assessed for visibility. The patterns of demarcation of each structure from adjacent ones were assessed. The width and the thickness of each tendinous band were measured on sagittal images. RESULTS: The SSa, the SSp and the IS tendons were distinguishable in all patients. The anterior part of the IS tendon overlapped the SSp tendon to reach a quite anterior insertion into the greater tuberosity of the humerus. The SSa, the SSp and the IS tendons were 6.5-3.4, 15.1-2.8 and 26.8-2.2 mm wide and thick, respectively. CONCLUSION: MR images of the normal superior rotator cuff are consistent with latest anatomical descriptions. The distal superposition of the IS over the SSp tendon should be considered regarding the linear increased signal areas and the commonly named "partial thickness ruptures" of the superior rotator cuff as well as the fatty infiltration of the IS muscle.

Diagnostic accuracy and variability of three semi-quantitative methods for assessing right ventricular systolic function from cardiac MRI in patients with acquired heart disease.

OBJECTIVES: To evaluate the diagnostic accuracy and variability of 3 semi-quantitative (SQt) methods for assessing right ventricular (RV) systolic function from cardiac MRI in patients with acquired heart disease: tricuspid annular plane systolic excursion (TAPSE), RV fractional-shortening (RVFS) and RV fractional area change (RVFAC). METHODS: Sixty consecutive patients were enrolled. Reference RV ejection fraction (RVEF) was determined from short axis cine sequences. TAPSE, RVFS and RVFAC were measured on a 4-chamber cine sequence. All SQt analyses were performed twice by 3 observers with various degrees of training in cardiac MRI. Correlation with RVEF, intra- and inter-observer variability, and receiver operating characteristic (ROC) curve analysis were performed for each SQt method. RESULTS: Correlation between RVFAC and RVEF was good for all observers and did not depend on previous cardiac MRI experience (R range = 0.716-0.741). Conversely, RVFS (R range = 0.534-0.720) and TAPSE (R range = 0.482-0.646) correlated less with RVEF and depended on previous experience. Intra- and inter-observer variability was much lower for RVFAC than for RVFS and TAPSE. ROC analysis demonstrated that RVFAC <41% could predict a RVEF <45% with 90% sensitivity and 94% specificity. CONCLUSIONS: RVFAC appears to be more accurate and reproducible than RVFS and TAPSE for SQt assessment of RV function by cardiac MRI.

Effect of the ellipsoid shape of the left ventricular outflow tract on the echocardiographic assessment of aortic valve area in aortic stenosis.

BACKGROUND: Previous studies showed discrepancies between echocardiographic and multidector row CT (MDCT) measurements of aortic valve area (AVA). OBJECTIVE: Our aim was to evaluate the effect of the ellipsoid shape of the left ventricular outflow tract (LVOT), as shown and measured by MDCT, on the assessment of AVA by transthoracic echocardiography (TTE) in patients with severe aortic stenosis. METHODS: This retrospective single-center study involved 49 patients with severe aortic stenosis referred before transcatheter aortic valve implantation. The AVA was deduced from the continuity equation on TTE and from planimetry on cardiac MDCT. Area of the LVOT was calculated as follows: on TTE, from the measurement of LVOT diameter on parasternal long-axis view; on MDCT, from manual planimetry by using multiplanar reconstruction perpendicular to LVOT. RESULTS: At baseline, correlation of TTE vs MDCT AVA measurements was moderate (R = 0.622; P < .001). TTE underestimated AVA compared with MDCT (0.66 ± 0.15 cm2 vs. 0.87 ± 0.15 cm2; P < .001). After correcting the continuity equation with the LVOT area as measured by MDCT, mean AVA drawn from TTE did not differ from MDCT (0.86 ± 0.2 cm2) and correlation between TTE and MDCT measurements increased (R = 0.704; P < .001). CONCLUSION: Assuming that LVOT area is circular with TTE results in constant underestimation of the AVA with the continuity equation compared with MDCT planimetry. The elliptical not circular shape of LVOT largely explains these discrepancies.

Cardiac MRI assessment of right ventricular function in acquired heart disease: factors of variability.

RATIONALE AND OBJECTIVES: To evaluate intra- and inter-observer variability of right ventricular (RV) functional parameters as evaluated by cardiac magnetic resonance imaging (MRI) in patients with acquired heart disease (AHD), and to identify factors associated with an increased variability. MATERIALS AND METHODS: Sixty consecutive patients were enrolled. Right and left ventricular (LV) volumes, ejection fraction, and mass were determined from short-axis cine sequences. All analyzes were performed twice by three observers with various training-degree in cardiac MRI. Intra- and inter-observer variability was evaluated. The impact on variability of each of the following parameters was assessed: observer's experience, basal and apical slices selection, end-systolic phase selection, and delineation. RESULTS: Mean segmentation time ranged 9.8-19.0 minutes for RV and 6.4-9.2 minutes for LV. Variability of RV functional parameters measurement was strongly influenced by previous observer's experience: it was two to three times superior to that of LV, even for the most experienced observer. High variability in the measurement of RV mass was observed. For both ventricles, selection of the basal slice and delineation were major determinants of variability. CONCLUSION: As compared to LV, RV function assessment with cardiac MRI in AHD patients is much more variable and time-consuming. Observer's experience, selection of basal slice, and delineation are determinant.