• Chronic thromboembolic pulmonary hypertension (CTEPH) is potentially treatable by surgery. • Dual-energy computed tomography (DECT) allows angiography and perfusion using a single acquisition. • Both DECT perfusion and angiography showed satisfactory diagnostic performance in CTEPH. • DECT perfusion was more accurate than angiography in identifying segmental abnormalities.
Studies of percutaneous cryotherapy in the treatment of benign or malignant soft tissue tumours are rare and mainly involve small populations. Nevertheless, results show cryotherapy's potential in terms of local control of tumours, analgesic efficacy, reduced intra- and postoperative complications, and reduction in the length of convalescence after the procedure. The objective of this update is to set out the short-term prospects for this technique in the treatment of soft tissue tumours, so that it may be more widely offered in these indications.
Background
Due to the very short T2 of its components, the normal anatomy of Achilles enthesis is impossible to define with “conventional” long echo time (TE) T2 sequences. However, this is a common site affected by rheumatologic disease. Early abnormalities related to inflammatory processes are impossible to detect in this location.
Purpose
To assess the feasibility of a 3D‐UTE (ultrashort echo time) sequence to evaluate normal and pathological Achilles entheses, determining both anterior fibrocartilaginous and posterior collagenic portions at 4.7T, in a rat model of spondyloarthropathy (SpA) with histological correlation. To assess whether this sequence detects SpA enthesopathy prior to long TE T2 sequences, enabling disease monitoring.
Study Type
Prospective case–control study.
Animal Model
Twelve immunocompetent Wistar male rats imaged before (controls); the model was induced in eight rats (16 tendons) imaged at day 6, day 13, and day 21 with regular sacrifice for ex vivo imaging and histological correlation.
Field Strength
4.7T Bruker Biospec Systems. 3D balanced steady‐state free precession (bSSFP) and 3D‐UTE sequences, performed at baseline (day 0, n = 12 animals / 24 tendons), day 6 (n = 8/16), 13 (n = 4/8), and day 21 (n = 2/4).
Assessment
Visual analysis and signal intensity measurements (signal to noise ratio, SNR) of both bSSFP and UTE images were performed by two independent musculoskeletal radiologists at different locations of the Achilles enthesis and preinsertional area.
Statistical Tests
Normal and pathological rat values were compared by Wilcoxon signed‐rank tests, as well as interobserver differences. MRI findings were compared against histological data.
Results
The 3D‐UTE sequence identified the anterior fibrocartilage and posterior collagenic areas of Achilles entheses in all cases. Visual analysis and signal intensity measurements distinguished SpA‐affected entheses from healthy ones at days 6 and 13 (P = 0.002 and P = 0.006, respectively). Neither the normal anatomy of the enthesis nor its pathological pattern could be identified on T2 bSSFP sequences.
Data Conclusion
Unlike bSSFP T2 sequences, 3D‐UTE sequences enable visualization of normal enthesis anatomy and early detection of abnormalities in pathological conditions.
Level of Evidence: 2
Technical Efficacy: Stage 2
J. Magn. Reson. Imaging 2019;50:127–135.
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