Intravoxel incoherent motion (IVIM) imaging in human achilles tendon.
J Magn Reson Imaging
; 48(6): 1690-1699, 2018 12.
Article
em En
| MEDLINE
| ID: mdl-29741808
ABSTRACT
BACKGROUND:
Limited microcirculation has been implicated in Achilles tendinopathy and may affect healing and disease progression. Existing invasive and noninvasive approaches to evaluate tendon microcirculation lack sensitivity and spatial coverage.PURPOSE:
To develop a novel Achilles tendon intravoxel incoherent motion (IVIM) MRI protocol to overcome the limitations from low tendon T2 /T2 * value and low intratendinous blood volume and blood velocity to evaluate tendon microcirculation. STUDY TYPE Prospective.SUBJECTS:
Sixteen healthy male participants (age 31.0 ± 2.1) were recruited. FIELD STRENGTH/SEQUENCE A stimulated echo readout-segmented echo planar imaging (ste-RS-EPI) IVIM sequence at 3.0T. ASSESSMENT The feasibility of the proposed ste-RS-EPI IVIM protocol combined with Achilles tendon magic angle effect was evaluated. The sensitivity of the protocol was assessed by an exercise-induced intratendinous hemodynamic response in healthy participants. The vascular origin of the observed IVIM signal was validated by varying the diffusion mixing time and echo time. STATISTICAL TESTS Two-tailed t-tests were used to evaluate differences (P < 0.05 was considered significant).RESULTS:
Consistent with known tendon hypovascularity, the midportion Achilles tendon at baseline showed significantly lower IVIM-derived perfusion fraction (fp ) (3.1 ± 0.9%) compared to the proximal and distal Achilles tendon (6.0 ± 1.8% and 6.1 ± 2.0%, respectively; P < 0.01). Similarly, the midportion Achilles tendon exhibited significantly lower baseline blood flow index (D*×fp ) (40.9 ± 19.2, 18.3 ± 5.3, and 32.0 ± 9.4 in proximal, midportion, and distal Achilles tendon, respectively; P < 0.01). Eccentric heel-raise exercise led to â¼2 times increase of Achilles tendon blood flow in healthy participants. Consistent with its vascular origin, the estimated fp demonstrated a high dependency to IVIM protocol parameters, while the T1 /T2 -corrected absolute intratendinous microvascular blood volume fraction (Vb ) did not vary. DATACONCLUSION:
Achilles tendon ste-RS-EPI IVIM noninvasively assessed baseline values and exercise-induced changes to tendon microcirculation in healthy tendon. LEVEL OF EVIDENCE 1 Technical Efficacy Stage 2 J. Magn. Reson. Imaging 2018;481690-1699.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tendão do Calcâneo
/
Processamento de Imagem Assistida por Computador
Tipo de estudo:
Observational_studies
Limite:
Adult
/
Humans
/
Male
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article