Application of Cardiac Proton Magnetic Resonance Spectroscopy to Measure Myocardial Steatosis in Women with HIV on ART: a Case Report

Presenting Author(s)

• 

  Petronella Samuels, MSc

  Head Radiographer at the Cape Universities Body Imaging Centre
  University of Cape Town
  Cape Town, Western Cape, South Africa

Primary Author(s)

• 

  Petronella Samuels, MSc

  Head Radiographer at the Cape Universities Body Imaging Centre
  University of Cape Town
  Cape Town, Western Cape, South Africa

Co-Author(s)

• 

  Olukayode O. Aremu, PhD

  Postdoctoral Research Fellow
  University of Cape Town
  Cape Town, Western Cape, South Africa
• 

  Morne F. Kahts, MD, MBA

  Radiology Registrar
  Groote Schuur Hospital & University of Cape Town
  Cape Town, Western Cape, South Africa
• PM

  Patricia Maishi, MSc

  Senior Radiographer
  University of Cape Town, South Africa
• MJ

  Mariaan Jaftha, MSc

  Senior Radiographer
  University of Cape Town, South Africa
• NT

  Natasha Taylor-Meyer, MSc

  Research Coordinator
  University of Cape Town
  Capetown, Western Cape, South Africa
• MA

  Marguerite Adriaanse, MD

  Medical Officer
  University of Cape Town
  Capetown, Western Cape, South Africa
• SS

  Sango Skelem, RN

  Research Nurse
  Groote Schuur Hospital, Cape Town
  Capetown, Western Cape, South Africa
• SJ

  Stephen Jermy, MSc

  Research Fellow
  University of Cape Town
  Cape Town, Western Cape, South Africa
• LS

  Lidia Szczepaniak, PhD

  Consultant
  MRS Consulting in Biomedical Research
  Albuquerque, New Mexico, United States
• BA

  Boni Ale, MD

  Director, Health Data Acumen
  Nairobi, Kenya, Nairobi Area, Kenya
• MZ

  Markella V. Zanni, MD

  Professor of Medicine
  Massachusetts General Hospital
  Boston, Massachusetts, United States
• CL

  Chris Longenecker, MD, PhD

  Professor of Medicine
  University of Washington Medical Center, United States
• NN

  Ntobeko A. B. Ntusi, MD DPhil

  Cape Town, Western Cape, South Africa

Description of Clinical Presentation: With the success of antiretroviral therapy (ART), women with HIV (WWH) in sub-Saharan Africa (SSA) are living longer but face a burden of cardiovascular disease (CVD). Myocardial steatosis, characterised by increased intramyocardial triglyceride (IMTG) content, contributes to diastolic dysfunction and heart failure. However, few prior studies have focused on characterising IMTG among a primary CVD prevention cohort of WWH in SSA. Cardiac proton magnetic resonance spectroscopy (¹H cMRS) offers a sensitive and noninvasive means for quantifying myocardial fat content in vivo. Neilan et al. reported that IMTG content above 0.5% was elevated, with levels exceeding 1.5% considered markedly increased. We report on a 57-year-old woman with HIV who underwent ¹H cMRS as part of a study investigating Myocardial Fibrosis and Steatosis Burden and Region-Specific Predictors of Progression among ART-treated WWH in sub-Saharan Africa (MUTIMA). Our participant had no prior history of CVD but presented with a body mass index of 39, suggestive of class II obesity, a known contributor to ectopic fat accumulation.

Diagnostic Techniques and Their Most Important Findings: To investigate IMTG accumulation, we employed ¹H cMRS using a 3T Siemens Magnetom Skyra scanner (Erlangen, Germany) equipped with Syngo VE11 software. ¹H cMRS was performed using a spin-echo Point Resolved Spectroscopy (PRESS) sequence (voxel size: 6 × 16 × 18 mm³, echo time (TE) of 35 ms, and 32 signal averages). The voxel was positioned in the interventricular septum using end-systolic pseudo four-chamber and short-axis cine views (Figure 1). Repetition time (TR) was set to a minimum of four times the R-R interval (≥4 × 800 ms) and adjusted for respiratory rate, with respiratory gating and cardiac triggering applied. Trigger delay was calculated as: TD = T_es – T_es/10. Cardiac geometry and function were assessed using a standard CMR protocol, including balanced steady-state-free-precession (bSSFP) cine sequences in four-chamber, two-chamber and short-axis orientations, phase-sensitive-inversion-recovery (PSIR) to assess late gadolinium enhancement (LGE), and T1 and T2 myomaps to quantify myocardial fibrosis and oedema.

Learning Points from this Case: CMR demonstrated preserved biventricular function (LVEF 63%, RVEF 53%). Native T1 times were elevated (1285 ms), with normal T2 values (47 ms). Diffuse, circumferential LGE was present (LGE mass: 11 g; 33%). IMTG was markedly elevated (3.08%), as quantified on ¹H cMRS (Fig. 1). The findings suggest early myocardial tissue alterations despite preserved systolic function.

In this case, markedly increased IMTG ( > 1.5%) was observed in an ART-treated WWH with obesity but no overt CVD. These findings suggest that obesity may independently contribute to myocardial steatosis in WWH. Future longitudinal studies may be needed to assess whether elevated IMTG precedes myocardial dysfunction, thereby contributing to the pathogenesis of heart failure with preserved ejection fraction in this population.

Figure 1: Myocardial triglyceride measurement: Representative cardiac 1H MRS in vivo from a voxel in the interventricular septum, showing cardiac water, cardiac metabolites, and a high peak of cardiac fat at approximately 1.4 ppm. Pseudo four-chamber image inset shows voxel positioning (green rectangle) in the septum.