ABSTRACT
Aim/Introduction: The evolution of the COVID-19 pandemic has led to the appearance of a spectrum of pulmonary parenchymal and vascular pathology related to the disease, including the development of fibrosis and chronic thromboembolic disease. The aim of this study is to assess the utility of lung scintigraphy with SPECT/CT in the respiratory complications in post-COVID patients. Material(s) and Method(s): Retrospective-prospective study that included 55 consecutive patients aged 27 to 84 years (55+/-11 y.o., 31 women) from April/2020 to January/2022, from two nuclear medicine centers in Uruguay and one in Argentina. Patients presented with dyspnea (n=52), chest pain (n=1), right heart failure (n=1) or O2 desaturation (n=1). Lung scintigraphy with 99mTc-MAA included planar images and SPECT/CT of the chest. Twenty-three patients underwent ventilation scintigraphy with 99mTc-DTPA. All the patients had a negative RT-PCR test for SARS CoV-2. Result(s): Most common risk factors included age > 55 years in 29 patients, diabetes in 10, obesity in 18 and hypertension in 30. Nine patients had asthma or COPD. Thirty-eight patients required hospitalization (8 in moderate care, 23 in ICU). All patients required O2 and received thromboprophylaxis during the illness. Only 4 patients had D-dimers, elevated in all of them. Six patients had Doppler ultrasound, negative in all of them. Seven patients had previous CT angiography, positive in 2. SPECT/CT was positive for pulmonary embolism (PE) in 10 patients (18%). Nine of them had ventilation studies. All presented typical segmental and/or subsegmental V/Q mismatches predominantly in the upper lobes and middle lobe. Thirteen patients (24%) presented matched defects, 11 of them with structural alterations on CT. CT abnormalities consisted of a reticular pattern with ground glass areas, consolidation foci and bilateral bronchiectasis. Two patients presented pleural effusion and 1 pericardial effusion. 3 patients with mismatched defects associated CT alterations. In clinical follow-up, all patients positive for PE were anticoagulated and improved after treatment. None of the patients presented PE during the acute phase of the disease. Conclusion(s): SPECT/CT lung scintigraphy is a useful tool to identify PE in patients with post-COVID syndrome. Beyond its advantages in the detection of small-vessel defects and the evaluation of chronic PE compared to CT angiography, the hybrid technique can demonstrate persistent pulmonary alterations that may explain the symptoms, separating the hemodynamic sequelae of deconditioning from limitations related to respiratory dysfunction in a new clinical situation that has the potential to become a public health problem.
ABSTRACT
Aim/Introduction: Sentinel lymph node (SLN) biopsy is widely accepted for lymph node staging in breast cancer, intermediaterisk melanoma and low-grade cervical cancer. The reproducibility of lymphatic drainage is a fundamental premise behind this procedure, but it has not been sufficiently studied yet. The aim is to evaluate the reproducibility of the lymphoscintigraphy for SLN detection in breast cancer, melanoma and cervical cancer using SPECT/CT images. Material(s) and Method(s): Retrospective study from February/2009 to October/2021 that included 64 consecutive patients (36-81 y.o., 62+/-11 years, 60 female) who underwent SLN study on two consecutive occasions due to suspension of the surgical procedure for different reasons (insufficient fasting, respiratory infection, hypertension, coordination problems, COVID-19). Fifty-six had breast cancer, 6 had melanoma and 2 cervical cancer. The interval between the two studies was 1-112 days. Patients with previous breast surgery or excisional biopsy were excluded. The radiopharmaceutical used was 99mTc-nanocolloid by subdermal periareolar injection in breast cancer, in 4 points surrounding the surgical scar in melanoma and in 4 points in the cervix in cervical cancer. Planar images followed by SPECT/CT of the region were acquired. Result(s): In the 56 patients with breast cancer, 115 SLNs were detected in the first procedure (85 level I, 20 level II and level III and 2 in the internal mammary chain) and 120 SLNs in the second procedure (87 level I, 24 level II, 8 level III and 1 internal mammary chain). One patient did not show SLN uptake in the first study and 2 level I SLNs were observed in the second. Ninety-eight percent concordance was observed in the topography of the SLNs of the level I. In the 6 patients with melanoma (2 of the upper limbs, 2 of the lower limbs, one from the back and one from the head) 21 SLNs were detected. The topography of the SLN was concordant in all cases. In the 2 patients with cervical cancer, 6 nodes were detected (4 bilateral external iliac and 2 obturator nodes). One patient had bilateral SLNs in the first study and unilateral in the second. Conclusion(s): The technique showed high reproducibility in breast cancer and melanoma. Concordance was maintained even in patients who showed several SLNs, suggesting that the main determining factor is the individual variability of the lymphatic drainage, beyond possible differences in the technical conditions of the procedure. More data are needed for cervical cancer.