Decoding polymyalgia rheumatica, the role of Nuclear Medicine Imaging.

Polymyalgia rheumatica (PMR) is an inflammatory joint disease that presents in patients older than 50 years with prolonged morning pain and stiffness in the shoulder and hip joints and neck. The lack of specific clinical findings, laboratory signs, biomarkers and established imaging methods makes it difficult to diagnose patients with this disease. 18F-FDG PET/CT is a functional imaging technique that is an established tool in oncology and has also proven useful in the field of inflammatory diseases. The aim of this paper is to present literature evidence on the use of molecular imaging methods such as PET/CT for early diagnosis, assessment of disease activity and therapeutic response in PMR. At the same time, the advantages, disadvantages and contraindications of other methods are considered.

Contributions of nuclear medicine to malignant musculoskeletal tumor disease in children.

A diagnosis of cancer is frightening at any age, but especially when the patient is a child. Only what is suspected can be diagnosed, only what is known or at least known to exist is suspected, but musculoskeletal tumors are infrequent and therefore very difficult to diagnose or treat. Probably due to their infrequency, the complexity of the radiological images, histopathological appearance, as well as the serious consequences due to inadequate biopsies and treatments, musculoskeletal tumor pathology requires clinical management that must be carried out by a group of specialists with specific training, allowing an adequate diagnosis, introduction of adjuvant therapies, as well as surgical treatment, making multidisciplinary treatment essential today. Imaging studies provide essential information on the nature of each lesion, its size, its anatomical location, the effect on the surrounding bone or soft tissues and the involvement of adjacent joints and neurovascular structures. In this article the authors will discuss the advances in nuclear medicine techniques (scintigraphy, SPECT/CT and PET/CT) and their usefulness in the staging of pediatric malignant musculoskeletal tumors, as well as in the assessment of response, follow-up, and diagnosis of recurrence.

Review of imaging techniques for evaluating morphological and functional responses to the treatment of bone metastases in prostate and breast cancer.

Bone metastases are very common complications associated with certain types of cancers that frequently negatively impact the quality of life and functional status of patients; thus, early detection is necessary for the implementation of immediate therapeutic measures to reduce the risk of skeletal complications and improve survival and quality of life. There is no consensus or universal standard approach for the detection of bone metastases in cancer patients based on imaging. Endorsed by the Spanish Society of Medical Oncology (SEOM), the Spanish Society of Medical Radiology (SERAM), and the Spanish Society of Nuclear Medicine and Molecular Imaging (SEMNIM) a group of experts met to discuss and provide an up-to-date review of our current understanding of the biological mechanisms through which tumors spread to the bone and describe the imaging methods available to diagnose bone metastasis and monitor their response to oncological treatment, focusing on patients with breast and prostate cancer. According to current available data, the use of next-generation imaging techniques, including whole-body diffusion-weighted MRI, PET/CT, and PET/MRI with novel radiopharmaceuticals, is recommended instead of the classical combination of CT and bone scan in detection, staging and response assessment of bone metastases from prostate and breast cancer.Clinical trial registration: Not applicable.

Failure of scintigraphy lymphatic mapping in endometrial cancer. Causes and solutions. / Fallo del mapeo linfático gammagráfico en el cáncer endometrial. Causas y soluciones.

AIM: To evaluate the effect of technical problems and patient characteristics on sentinel lymph node (SLN) scintigraphic detection and mapping success in early stages of endometrial cancer (EC). METHODS: Patients with clinical early stage EC (IA-IB) underwent SLN mapping using technetium-99m-nanocolloid,between September 2011 and February 2020. were included. There were excluded cases with technical problems, 92 patients were included for the analysis of the diagnostic performance and the relation of mapping failure (pelvic unilateral or not detected SLN) with patient (age, body mass index, previous pelvic disease or surgery) and disease characteristics (histology, grade, myometrial invasion, lymphovascular space infiltration, tumor size, and lymphatic infiltration risk). RESULTS: The overall detection rate was 79%. Lymph node metastases were diagnosed in 7 patients. Age (p=0.01), depth of myometrial invasion ≥ 50% (p=0.04) and high risk of lymphatic infiltration (p=0.02) were positively associated with mapping failure. In multivariate analysis, age was significantly associated with mapping failure [odds ratio=1.63, 95%CI: 1.06-2.50; p=0.027]. CONCLUSIONS: Age, depth of myometrial invasion and high risk of lymphatic infiltration were the factors associated with higher mapping failure. An individualized injection technique, optimizing the methodology, could minimize the detection failures.

Diagnostic methodology in labelled leukocyte scan for prosthetic / non-prosthetic osteoarticular infection: Visual or semi-quantitative analysis? One- or two-day protocol? / Metodología de la gammagrafía con leucocitos marcados en el diagnóstico de infección osteoarticular protésica/no protésica: ¿análisis visual o semicuantitativo? ¿Protocolo de uno o 2 días?

OBJECTIVE: As scarce literature on the topic is available, we aimed to compare diagnostic utility of semi-quantitative versus visual analysis in labelled white blood cell scintigraphy (WBCS) for osteoarticular infection. One-day and two-day protocols were assessed, particularly in orthopaedic devices. MATERIAL AND METHODS: Prospective study of 79 consecutive patients with suspected osteoarticular infection. In all patients, WBCS were performed at 30min, 4h, 8h and 24h. Images were analysed by grouping in two protocols: one-day-protocol (experts evaluated 30min, 4h and 8h planar images) and two-day-protocol (experts evaluated 30min, 4h and 24h planar images). Planar images were interpreted qualitative and semiquantitatively and also were compared grouping patients with and without orthopaedic devices. To find which cut-off value of the percentage variation could predict of osteoarticular infection, multiple cut-off values were calculated in both protocols from the Youden index. Three blinded readers analysed the images. RESULTS: Comparing final diagnosis visual analysis of the one-day-protocol provided better results with sensitivity of 95.5%, specificity of 93% and diagnostic accuracy of 93.7% (P<.01) than the two-day-protocol with values of 86.4%, 94.7% and 92.4%, respectively (P<.01). For semi-quantitative analysis, the one-day-protocol also obtained better results with sensitivity of 72.7%, specificity of 78.9% and accuracy of 77.2% (P<.01) than two-day-protocol (no significant results; P=.14), especially in the group of patients with orthopaedic devices (sensitivity of 100%, specificity of 79.5% and accuracy of 82.7%; P<.01). CONCLUSIONS: Most accurate approach in the diagnosis of osteoarticular infection corresponded to visual analysis in one-day-protocol that showed greater sensitivity and specificity than semi-quantitative analysis. Semi-quantitative analysis only could be useful when visual analysis is doubtful. In patients with joint prostheses, an increase in percentage variation above 9% obtained maximum sensitivity and negative predictive value.

Contributions of nuclear medicine in paediatric non-tumour musculoskeletal pathology. / Aportaciones de la medicina nuclear en la enfermedad musculoesquelética no tumoral pediátrica.

Non-tumour musculoskeletal pathology in children represents a high percentage of the nuclear medicine studies requested by paediatricians. As these are immature bones and joints, in constant growth and remodelling, they present their own physiological and anatomical peculiarities that require a specific management for the paediatric age group. Using different clinical scenarios frequently observed in medical appointments (limping, back pain or fever, among others), we have summarised the possible findings or artefacts that can be obtained in the different Nuclear Medicine explorations, including bone scintigraphy and hybrid images such as PET/CT. To obtain high quality images requires careful attention to technique and positioning in children. Bone scintigraphy is a common paediatric nuclear medicine procedure and plays an important role in the diagnosis of musculoskeletal pathologies and can be complemented by techniques such as SPECT to improve localisation and diagnostic accuracy. In addition, 18F-FDG PET/CT is increasingly applied in the evaluation of children. This article reviews the usual indications of, mainly, bone scintigraphy and 18F-FDG PET/CT in paediatric non-tumour musculoskeletal diseases, how to interpret them properly, being essential to know the normal physiological distribution of each radiopharmaceutical, as well as the common variants of paediatric growth that can simulate disease, implying possible misinterpretations between normal and pathological structures.

Nuclear Medicine in the diagnosis of pathologies of the spine: role of hybrid imaging. / Medicina nuclear en el diagnóstico de las afecciones de la columna vertebral: papel de la imagen híbrida.

Clinical problems in the human spine are still common in our society, often causing pain and can also limit movement. Back pain is a very common clinical entity, although difficult to diagnose due to its multifactorial nature. There are multiple processes that can alter the structure of the spine, injure vertebrae and/or the surrounding tissue. For the study of the spine, image diagnosis is essential, and within this, molecular hybrid techniques play an important role by providing us with an image of functional and morphological fusion. Among these, SPECT/CT is key in the diagnosis of traumatic and stress pathology, allowing us to locate hidden vertebral fractures, and is also very useful in degenerative and post-surgical pathology. On the other hand, PET/CT with 18F-FDG also plays an important role in the management and monitoring of infectious and oncological processes. This review describes the application of these hybrid techniques in the different pathologies of the spine and the findings of their images, being very useful for the diagnostic assessment and therapeutic management of the patient.

Role of Nuclear Medicine in the diagnosis of musculoskeletal infection: a review. / Revisión del papel de la Medicina Nuclear en el diagnóstico de la infección musculoesquelética.

Inflammatory and infectious osteoarticular diseases can cause serious consequences for the patient if they are not diagnosed on time. In the last decades, different modalities of nuclear medicine have allowed to study the physiopathology of these processes, and nowadays, they play an important role in diagnosis, characterization and monitoring of musculoskeletal infectious diseases. Therefore, it is essential that every nuclear medicine physician have a vision of the advantages and disadvantages of each method and know how to use them correctly in the diagnosis of the patient. This article highlights the role of nuclear medicine in standardizing the diagnostic approach in patients with infectious/inflammatory diseases, in particular in peripheral osteomyelitis, septic arthritis, prosthetic joint infections, infected diabetic foot and spinal infections. The authors reveal the role of the most common radionuclides tests, with their advantages and clinical indications, to achieve an adequate diagnosis of infection and inflammation.

One-day protocol versus two-day protocol in acquisition of scintigraphy with "in vitro" labelled white blood cells for diagnosis of osteoarticular infection. / Protocolo de un día vs protocolo de dos días de adquisición mediante gammagrafía con leucocitos marcados in vitro para el diagnóstico de infección osteoarticular.

INTRODUCTION: It is difficult to determine osteoarticular infection and differentiate inflammation from infection with laboratory and imaging procedures (CT, MRI, US). Labelled white-blood-cell scintigraphy (WBCS) is the nuclear medicine test of choice but it takes two days, sometimes finds it difficult to differentiate soft tissue from bone infection and therefore causes interobserver variability, which decreases its specificity. OBJECTIVE: To demonstrate the usefulness of the one-day protocol with time decay-corrected acquisition in WBCS to diagnose osteoarticular infection and to reduce interobserver variability. The role of SPECT/CT in WBCS in locating the infected focus was also evaluated. METHODS: 110 patients with suspected osteoarticular infection were studied prospectively. Planar images were obtained with time decay-corrected acquisition at 30min, 4h, 8h and 24h. WBCS planar images were grouped in two protocols: One-day protocol: experts evaluated 30min, 4h and 8h images. Two-day protocol: experts evaluated 30min, 4h and 24h images. Both protocols were classified as: SPECT/CT was performed in 72 patients. Kappa index was calculated to evaluate interobserver variability. RESULTS: Infection was confirmed in 34 cases. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were 97.1%, 97.4%, 94.3%, 98.7%, and 97.3% for the one-day protocol and 94.1%, 97.4%, 94.1%, 97.4%, and 96.4% for two-days-protocol. SPECT/CT contributed to diagnosis in 45/50 patients with planar WBCS positive. Kappa index: 0.8 for one-day protocol and 0.79 for two-day protocol, respectively. CONCLUSION: One-day protocol with time decay-corrected acquisition WBCS and SPECT/CT enables early and accurate diagnosis of osteoarticular infection.

Hybrid imaging in foot and ankle disorders. / Imagen híbrida en la patología del pie y tobillo.

Disorders of the foot and ankle are some of the most frequent ones affecting the musculoskeletal system and have a great impact on patients' quality of life. Accurate diagnosis is an important clinical challenge because of the complex anatomy and function of the foot, that make it difficult to locate the source of the pain by routine clinical examination. In the study of foot pathology, anatomical imaging (radiography, magnetic resonance imaging [MRI], ultrasound and computed tomography [CT]) and functional imaging (bone scan, positron emission tomography [PET] and MRI) techniques have been used. Hybrid imaging combines the advantages of morphological and functional studies in a synergistic way, helping the clinician manage complex problems. In this article we delve into the anatomy and biomechanics of the foot and ankle and describe the potential indications for the current hybrid techniques available for the study of foot and ankle disease.