Molecular Imaging of Pulmonary Tuberculosis in an Ex-Vivo Mouse Model Using Spectral Photon-Counting Computed Tomography and Micro-CT

Assessment of disease burden and drug efficacy is achieved preclinically using high resolution micro computed tomography (CT). However, micro-CT is not applicable to clinical human imaging due to operating at high dose. In addition, the technology differences between micro-CT and standard clinical CT prevent direct translation of preclinical applications. The current proof-of-concept study presents spectral photon-counting CT as a clinically translatable, molecular imaging tool by assessing contrast uptake in an ex-vivo mouse model of pulmonary tuberculosis (TB). Iodine, a common contrast used in clinical CT imaging, was introduced into a murine model of TB. The excised mouse lungs were imaged using a standard micro-CT subsystem (SuperArgus) and the contrast enhanced TB lesions quantified. The same lungs were imaged using a spectral photoncounting CT system (MARS small-bore scanner). Iodine and soft tissues (water and lipid) were materially separated, and iodine uptake quantified. The volume of the TB infection quantified by spectral CT and micro-CT was found to be 2.96 mm(3) and 2.83 mm(3), respectively. This proof-of-concept study showed that spectral photon-counting CT could be used as a predictive preclinical imaging tool for the purpose of facilitating drug discovery and development. Also, as this imaging modality is available for human trials, all applications are translatable to human imaging. In conclusion, spectral photon-counting CT could accelerate a deeper understanding of infectious lung diseases using targeted pharmaceuticals and intrinsic markers, and ultimately improve the efficacy of therapies by measuring drug delivery and response to treatment in animal models and later in humans

Penelusuran Jalur Saraf Nyeri Dada pada Jantung Kelinci yang Mengalami Iskemia Miokardium dengan Metode Dual- Retrograde Neurotracing

Iskemia miokardium terjadi ketika suplai oksigen ke otot jantung tidak adekuat dibanding dengan kebutuhan jantung tersebut. Iskemia miokardium ini akan menyebabkan angina pectoris atau nyeri dada yang menjalar. Nyeri menjalar tersebut berasal dari saraf aferen viseral jantung yang diduga memiliki jaras bersama dengan beberapa saraf aferen somatis, sehingga diinterpretasi oleh otak bahwa nyeri tersebut berasal dari saraf somatis. Penelitian ini bertujuan untuk mengetahui ada atau tidak daerah spesifik jantung yang terproyeksi secara neuronal ke ganglia spinalis segmen tertentu. Untuk menelusuri proyeksi tersebut digunakan metode dual-retrograde neurotracing dengan tinta True Blue (TB) dan Nuclear Yellow (NY). Kelinci dibagi menjadi 3 kelompok, kelompok yang diligasi di ramus interventricularis anterior arteri coronaria sinistra (P1), kelompok yang diligasi di ramus circumflexa arteri coronaria sinistra (P2), dan kelompok kontrol (K). Kelompok P1 dan P2 diinjeksi dengan TB pada daerah yang iskemia setelah proses ligasi. Kelompok K diinjeksi TB di daerah yang sama dengan P1 & P2 namun tanpa ligasi. Semua kelompok kemudian diinjeksi NY pada kulit setinggi T1-T4. Hasil penelitian ini membuktikan bahwa terdapat hubungan yang signifikan antara lokasi ligasi dengan proyeksi pada ganglion spinalis tertentu (p<0,05). P1 menunjukkan kecenderungan untuk terproyeksi di T2, sedangkan P2 terproyeksi di T1. Dapat disimpulkan bahwa pada jantung kelinci dapat ditentukan area specific dari jantung yang terproyeksi secara neuronal ke ganglia spinalis, setelah dilakukan ligasi

NEURAL PAIN PATHWAY TRACING OF RABBIT ISCHEMIC HEART BY DOUBLE-RETROGRADE NEUROTRACING

Background. Myocardial ischaemia occurs due to inadequate supply of oxygen to fulfill the myocardial tissue oxygen demand. This leads to angina pectoris or referred pain, whichhappens because of the inability of the brain to distinguish the visceral afferent inputs from the somatic afferent inputs since they run along a common pathway via the dorsal root ganglia. Aims. This study aims to distinguish specific areas of the rabbit heart that are projected to specific dorsal root ganglia, which then associates to its specific dermatomes. Methods. A double-retrograde neurotracing method was used, with True Blue and Nuclear Yellow as the neurotracers. Rabbits were divided into 3 groups, which the first and second groups were ligated at the left anterior descending artery and at the left circumflex artery, respectively.The third group acted as the control group, without ligation.True blue was injected at ischaemic sites following ligation. Nuclear yellowwas injected at the skin, dermatomes T1-T4. Dorsal root ganglia levels T1-T4 were then examined for both neurotracers at 3 days post injection. Results. There is significant association between the site of ligation to the projection of the neurotracers at specific dorsal root ganglia (p<0.05). The first group showed high tendency to be projected to T2 and the second group showed a high tendency to project to T1. Conclusion. This study shows that the rabbit heart can be specifically projected neuronally to specific dorsal root ganglia, following coronary artery ligation