Diagnostic imaging in dermatology: utility of PET-CT in cutaneous melanoma.

Malignant melanoma accounts for 5% of all malignant skin tumors and its incidence is increasing. In the natural course of melanoma, tumors grow locally and can spread via the lymph system or the blood. Because survival is directly related to the stage of the disease at diagnosis, early detection (secondary prevention) has an impact on prognosis. Positron emission tomography (PET) is a nuclear medicine technique that generates images using molecules labeled with positron-emitting isotopes. The most widely used molecule is fluorodeoxyglucose (FDG). Because of the elevated glycolytic rate in tumor cells, which results in increased FDG uptake, greater quantities of FDG become trapped in tumor cells, enabling external detection. Today, most PET scanners are multimodal PET-computed tomography (CT) scanners, which provide more detailed information by combining morphological information with functional PET findings. The possible utility of PET-CT in patients with malignant melanoma is a subject of debate. Various questions have been raised: when the scan should be performed, whether PET-CT has advantages over conventional diagnostic methods, and whether PET-CT provides a real benefit to patients. In this review of the literature, we will analyze each of these questions.

Role of the clinical radiopharmacist in patient safety during myocardial perfusion imaging with vasodilator stress agents.

AIM: To assess the radiopharmacist's role in a multidisciplinary team focused on the contraindications of regadenoson in order to ensure the safe use of pharmacologic vasodilator stress agents in patients undergoing SPECT-MPI. METHODS: We ambispectively studied its safe use in 1905 patients (54.1% female, mean age: 66.6±11.7 years, range: 20-95 years). Sex, age, medical history, medications, drug allergies, and contraindications for stress testing were registered together with recommendations for the nuclear physician in charge. RESULTS: Detected contraindications and corresponding recommendations were as follows: risk factors for QTc interval prolongation 7.5% - measurement of QTc interval previously to test and monitor ECG; prior stroke or TIA 4.2% - consider carotid stenosis assessment; salicylates/sulfonamides allergy 3.1% - use 99mTc-sestamibi; epilepsy or risk factors for seizures 2.4% - use of adenosine or reconsider test indication; systemic corticosteroid therapy for severe COPD 1.3% - reassessment of patient's condition; acute exacerbation of COPD 0.8% - defer test until acute episode is over; severe asthma 0.4% - do not perform test; methylxanthine ingestion 0.3% - avoid consumption previously; other 6.1% - evaluation of other contraindications. No contraindications were detected in 73.6% of patients. The test was canceled due to absolute contraindications in 2.9% of the requests. CONCLUSIONS: Working in a systematic way, the radiopharmacist was able to detect a high number of issues related to regadenoson, with one out of four patients presenting some clinical contraindication. The recommendations given by the radiopharmacist were well accepted by the nuclear physicians who changed their approach contributing to increase the safety of patients referred for MPI.

Assessment of pulmonary embolism related to active SARS-CoV-2 infection in pregnant women.

AIM: To analyze a sample of pregnant patients who underwent pulmonary perfusion scintigraphy to rule out suspicion of pulmonary embolism (PE) during the acute COVID-19 infection hospitalization period in our hospital. MATERIAL AND METHODS: SPECT scintigraphy with a reduced dose (111MBq) of 99mTc-macroaggregated albumin was performed in all the patients (n=5). The images obtained were interpreted by comparing the findings with the radiological images according to the PISAPED criteria. RESULTS: Only one of the 5 patients was diagnosed with PE. Two patients showed pathological scintigraphy findings attributable to radiological alterations due to COVID-19 pneumonia, and the other two had normal pulmonary perfusion. CONCLUSION: Given the non-specific features of the clinical manifestations and d-dimer values ​​in COVID-19, as well as their similarity to those of PE, pulmonary perfusion scintigraphy plays a crucial role in the screening of PE in these patients due to its high sensitivity and lower irradiation compared to CT. Despite the limited number of patients, the results obtained have special relevance due to the absence of scientific publications in this group of patients within the exceptional context of the COVID-19 pandemic.

Radioguided surgery with iodine-125 seeds in breast cancer patients treated with neoadjuvant chemotherapy.

OBJECTIVE: To evaluate the use of radioactive iodine-125 seed (RIS) in breast and/or axillary surgery, in patients with breast cancer treated with neoadjuvant chemotherapy (NAC). MATERIAL AND METHODS: Prospective study between January 2016 and June 2020. 80 women T1-3,N0-2,M0: 30 RIS marking the breast tumor, 36 both the tumor and the biopsied positive axillary node, and 14 only the axilla. Age: 54.7 ±â€¯11.4 years. Tumor size: 34.1 ±â€¯14.6 mm. Histological type: invasive ductal carcinoma 90.0%. Molecular subtypes: luminal-A 23.8%, luminal-B/HER2- 33.7%, luminal-B/HER2+ 18.8%, HER2+ 7.5%, basal-like 16,2%. RESULTS: Of the 66 patients with RIS marking of the tumor (51 pre-NAC, 15 post-NAC), 92.1% had tumor-free surgical margins, with a specimen volume of 126.7 ±â€¯111.2 cm3. Of the 5 s local excisions, in 3 the resection margin was involved (1 mastectomy). Of the 50 patients N1 with RIS marking (MLN), 44 pre-NAC and 6 post-NAC, MLN was identified in 97.2%: negative 23, positive 26. In 45/50 patients, sentinel node biopsy (SNB) was performed and it was identified in 93.3%: negative 26, positive 16. In 1 case RIS was not placed correctly and SNB was not identified due to non-migration. In 61.9% of the patients, MLN was among the SNB identified in the surgery. In 5 patients with mismatched SNB and MLN, the pathological result of the SNB was negative and the MLN was positive. Axillary lymph node dissection was performed in 53.8% of the patients. CONCLUSION: RIS allow to perform breast-conserving surgery and improve detection of residual axillary disease in patients treated with NAC.

Radioguided surgery with iodine-125 seeds in breast cancer patients treated with neoadjuvant chemotherapy. / Cirugía radioguiada con semillas de yodo-125 en pacientes con cáncer de mama tratadas con quimioterapia neoadyuvante.

OBJECTIVE: To evaluate the use of radioactive iodine-125 seed (RIS) in breast and/or axillary surgery, in patients with breast cancer treated with neoadjuvant chemotherapy (NAC). MATERIAL AND METHODS: Prospective study between January 2016 and June 2020. 80 women T1-3,N0-2,M0: 30 RIS marking the breast tumor, 36 both the tumor and the biopsied positive axillary node, and 14 only the axilla. Age: 54.7±11.4 years. Tumor size: 34.1±14.6mm. Histological type: invasive ductal carcinoma 90.0%. Molecular subtypes: luminal-A 23.8%, luminal-B/HER2- 33.7%, luminal-B/HER2+ 18.8%, HER2+ 7.5%, basal-like 16,2%. RESULTS: Of the 66 patients with RIS marking of the tumor (51 pre-NAC, 15 post-NAC), 92.1% had tumor-free surgical margins, with a specimen volume of 126.7±111.2 cm3. Of the 5 second local excisions, in 3 the resection margin was involved (1 mastectomy). Of the 50 patients N1 with RIS marking (MLN), 44 pre-NAC and 6 post-NAC, MLN was identified in 97.2%: negative 23, positive 26. In 45/50 patients, sentinel node biopsy (SNB) was performed and it was identified in 93.3%: negative 26, positive 16. In 1 case RIS was not placed correctly and SNB was not identified due to non-migration. In 61.9% of the patients, MLN was among the SNB identified in the surgery. In 5 patients with mismatched SNB and MLN, the pathological result of the SNB was negative and the MLN was positive. Axillary lymph node dissection was performed in 53.8% of the patients. CONCLUSION: RIS allow to perform breast-conserving surgery and improve detection of residual axillary disease in patients treated with NAC.

[Perivascular epithelioid tumors: Utility of the positron emission tomography with 18F-fluorodesoxyglucose (PET-TAC FDG) in their staging and follow-up]. / Tumor epitelioide perivascular uterino. Utilidad de la tomografía por emisión de positrones con (18)F-fluordesoxiglucosa en su estadificación y seguimiento.

Perivascular epithelioid tumors (PEComas) are a rare group of mesenchymal neoplasms with an unpredictable natural history and uncertain malignant potential. Uterine involvement and their association with tuberous sclerosis are typical for these tumors. We present a case of a 40-year old patient who was incidentally diagnosed of a uterine PEComa and serial studies of PET-CT with FDG were performed for staging and therapeutic response assessment. FDG PET-CT proved to be a valuable tool for detecting unsuspected pulmonary metastases and defining the reassessment of the patient after chemotherapy. The findings suggest that since this is a rare tumor, which does not always have benign behaviour, PET-CT may be a useful diagnostic imaging procedure for staging and clinical monitoring of patients who suffer this type of tumors.

[Fibrous dysplasia of the bone. Contribution of nuclear medicine in the diagnosis of suspicion of sarcomatous degeneration]. / Displasia fibrosa ósea. Aportación de la Medicina Nuclear al diagnóstico de sospecha de degeneración sarcomatosa.

Fibrous dysplasia (FD) is a relatively frequent benign disease of the bone in which there is a maturation disorder of the bone-forming mesenchyme where the lamellar bone marrow is replaced with abnormal fibrous tissue. Its diagnosis is often an accidental finding when X-ray studies or bone scans are performed for other reasons since it is usually asymptomatic. There may be complications such as deformities, pathological fractures and exceptionally malignant transformation. The differential diagnosis between malignancy and FD can be complicated and lead to late diagnosis when sarcomatous degeneration already exists. In this context, the positron tomography with (18)F-fluorodeoxyglucose (FDG-PET) may be useful in the monitoring of this condition. We present two cases of patients diagnosed of FD with suspicion of malignization of their bone lesions who were referred to Nuclear Medicin.

Surgical clips vs. iodine-125 (125I) seeds for marking the location of nonpalpable malignant breast lesions: preliminary results. / Arpón quirúrgico vs. semilla de iodo (125I) en la localización de lesiones no palpables malignas de mama. Resultados preliminares.

OBJECTIVES: To assess the usefulness of iodine-125 (125I) seeds as an alternative to surgical clips for marking the location of nonpalpable malignant breast lesions for surgery. MATERIAL AND METHODS: We included patients with histologically confirmed nonpalpable malignant lesions treated by surgery in 2015 or 2016. Patients were randomly assigned to presurgical marking with metallic clips (Group A) or with 125I seeds (Group B). In both groups, marking was guided by ultrasound and/or mammography depending on the radiologic characteristics of the lesion. During surgery, a gamma probe was used and afterward the presence of seeds in the surgical specimen was checked radiologically. In the histological analysis, the absence of tumor in the stain was considered free margins. We analyzed the following variables: age, lesion characteristics (laterality, mean size on MRI and in the surgical specimen, radiological type), and presence/absence of free margins. RESULTS: In Group A (n=53), the most common histologic subtypes were infiltrating ductal carcinoma (IDC, 84.9%) and luminal A (LA, 49.1%); the mean size of the lesions was 1.8cm. In Group B (n=45), the most common histologic subtypes were IDC (82.2%) and LA (46.5%); the mean size of the lesions was 1.5cm. In Group A, 13.2% had involved margins and 13.2% underwent a second surgical intervention. In Group, B 11.4% had involved margins and 7.5% underwent a second surgical intervention. The differences between groups were not significant (p=0.7 for involved margins and p=0.5 for reintervention). The volume of the surgical specimens was significantly lower in Group B than in Group A (128.68cm3 vs. 189.37cm3; p<0.05). CONCLUSIONS: Using 125I seeds was feasible and enabled significantly smaller surgical specimens than using metallic clips.

[18F-fluorodeoxyglucose positron emission tomography in the evaluation of therapy response assessment in lymphomas. Systematic literature review and meta-analysis]. / Tomografía de positrones con 18F-fluorodesoxiglucosa en la valoración de la respuesta de los linfomas al tratamiento. Revisión sistemática de la literatura y metaanálisis.

This systematic review of literature analyze the utility of positron emission tomography (PET or PET-CT) with 18F-fluorodeoxyglucose, as a diagnostic tool in the assessment of response to chemotherapy and immunotherapy in lymphomas, in terms of diagnostic accuracy in prospective publications. A literature search was conducted in major databases and through manual review from the reference lists of articles that were recovered. The methodological quality of the selected items was evaluated using the QUADAS questionnaire. 9 publications were analyzed after the filtering process. The methodological quality of the same was broadly acceptable. In patients with LH, the negative predictive value of FDG-PET after 2-3 cycles of chemotherapy, was ranged between 93.4% (95% CI, 92.6-94.3) and 100% (95% CI, 99.3-100%), and after the treatment, the negative predictive value of PET-FDG, was between 94.3% (95% CI, 92.8-95.7) and 100% (95% CI, 97.1-100). In patients with residual masses and LH, the meta-analysis of results showed a sensitivity of 100% (95% CI, 0.753-1) and a specificity of 84% (95% CI, 0.699-0.934). PET-FDG seems to be a useful tool to evaluate the response to treatment of patients with lymphoma. However, it recommended further prospective studies and that possibly conducted in hybrid PET-CT scans, to determine its usefulness.

[Gallbladder cancer staging with 18F-FDG PET-CT]. / Estadificación del cáncer de vesícula mediante tomografía de positrones con 18F-fluorodesoxiglucosa.

Gallbladder cancer is the most common biliary tract neoplasm. It generally affects the elderly, who are usually clinically asymptomatic. When symptoms appear, they suggest the presence of complications locally or due to tumour progression. Late diagnosis of the disease indicates a poor prognosis for these patients. Surgery is the only treatment with curative intent, but it is only possible in the early stages. Diagnostic imaging of this type of tumour is usually performed with ultrasonography, computed tomography or magnetic resonance cholangiography. Positron emission tomography (PET) with fluorodeoxyglucose (FDG) with dedicated scanners or hybrid PET-CT scans are new diagnostic tools which could help in the pre-surgical diagnosis of these tumours. We present three cases to illustrate the usefulness of PET-FDG in the pre-surgical staging of gallbladder cancer.

[Desmoid tumor of the thoraco-abdominal wall characterized with 18F-fluorodeoxyglucose PET/ CT scan. Correlation with magnetic resonance and bone scintigraphy. Review of the literature]. / Tumor desmoide de la pared torácico-abdominal. Caracterización con PET-TAC con 18F-fluorodesoxiglucosa y correlación con resonancia magnética y gammagrafía ósea. Revisión de la literatura.

Desmoid tumours are uncommon benign tumours but with aggressive behaviour, resulting from the proliferation of well-differentiated fibroblasts. Clinically, they present as a painless firm soft tissue mass. They can be solitary or multiple and have potential infiltrative capacity. When planning treatment, it is important to assess the correct tumour extent to permit curative radical surgery minimizing possible local recurrence. Different imaging techniques help to characterise these tumours. At present, magnetic resonance is the tool of choice for studying these tumours. The role of nuclear medicine techniques, such as bone scintigraphy, or more recently FDG-PET, has not been defined in the evaluation of these neoplasms. We present the case of a patient with a desmoid tumour of the abdominal-chest wall and we review the related literature.

125I radioactive seed localization for non-palpable lesions in breast cancer. / Semillas de 125I en la localización de lesiones no palpables en pacientes con cáncer de mama.

AIM: Marking of non-palpable breast lesions with 125I radioactive seeds is an alternative to the use of the surgical wire. The objective of this work is to present the results that we have obtained using radioactive seed localization compared to the reference technique in our center, the wire localization of non-palpable breast lesions. MATERIAL AND METHOD: Longitudinal prospective study that includes patients with histological diagnostic of breast cancer, with non-palpable lesions that are candidates to primary surgical treatment by radioactive seed localization (2016-2018) and by wire localization (2015-2016). Histological analysis of the surgical specimen was performed determining the status of surgical margins. The volume of the surgical specimen was calculated. RESULTS: A total of 146 patients were included, 95 who underwent surgery by radioactive seed localization and 51 by wire localization. The mean cube volume of the specimens were 135.67cm3 vs. 190.77cm3 (p=0.017), respectively. Eleven patients who underwent surgery by radioactive seed localization showed affected margins of the specimen (11.6%), versus 7 (13.2%) of wire localization group (p=0.084). Reintervention was performed in 9 of the patients marked with seeds and in 7 marked with wires (p=0.49). CONCLUSION: The use of 125I radioactive seeds is feasible in non-palpable breast lesions, with a low rate of reintervention and volumes of surgical specimens significantly lower than those obtained by wire localization.

[Circumscript myositis ossificans in a four-year-old boy]. / Miositis osificante circunscrita en un niño de cuatro años.

We present the case of a 4 year old boy with no previous personal or family history of interest, who attended the Paediatric Department of our hospital after a physical examination revealed a painful induration in the left arm which had increased in size; imaging tests were consistent with a calcified mass in soft tissues, without cortical involvement, suspected of being malignant. Two-phase bone scintigraphy was requested in which a soft tissue lesion, not suggestive of malignancy, was detected. The biopsy was negative for malignant cells. However, in view of the progressive increase in size of the lesion, FDG positron emission tomography (FDG-PET) was performed, showing a hypermetabolic mass consistent with malignancy in the left arm, for which the patient underwent surgery for suspected possible parosteal osteosarcoma.

[The role of bone scintigraphy in two cases of hereditary multiple exostoses]. / Papel de la gammagrafía ósea en dos casos de exóstosis múltiple hereditaria.

We present the cases of two patients aged 18 and 40 years, with no previous personal history of interest. The only symptoms reported by the first patient in the previous year were episodes of pain and stiffness without inflammation in the right knee and third finger of the right hand. These episodes lasted two to three weeks. Our second patient presented numbness in the lower left limb over the previous year. The analytical study was normal. The patients were diagnosed with hereditary multiple exostoses, based on the clinical, radiological and scintigraphic findings. The bone scintigraphy enabled whole body images to be obtained in a single examination and may be used for the differential diagnosis of other osteoarticular conditions, as well as for the follow-up and assessment of the response to treatment.

Review of the role of the sentinel node biopsy in neoadjuvant chemotherapy in women with breast cancer and negative or positive axillary node at diagnosis. / Actualización de la biopsia del ganglio centinela tras quimioterapia neoadyuvante en el cáncer de mama sin y con afectación ganglionar al diagnóstico.

The role of the selective sentinel node biopsy (SNB) is increasing in relevance in breast cancer women with indication of neoadjuvant chemotherapy (NAC). The Radiosurgery Working Group of the SEMNIM is aware of the necessity of establishing the need for SNB before or after NAC, and also how to manage patients with axillary node-negative or node-positive. There is sufficient data to assess that the SNB with radioisotope techniques are feasible and safe in all these scenarios. An adequate axilla evaluation prior to surgery and the possibility of marking prior to NAC the nodes infiltrated must be the two main pillars to guarantee the success of the SNB. It has been shown that to incorporate the SNB in breast cancer women with indication of NAC increases the rate of a conservative treatment of the axilla that will be a clear benefit for these patients.

[Positron emission tomography with 18F-fluorodeoxyglucose in patients with uterine sarcoma]. / Tomografía por emisión de positrones con 18F-fluordesoxiglucosa en pacientes con sarcoma uterino.

OBJECTIVE: Describe our experience with 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), in patients with uterine sarcomas, under suspicion of recurrence and in tumour staging after hysterectomy as an incidental pathology finding. MATERIAL AND METHODS: A retrospective review, between april 2002 and january 2006, of FDG-PET performed in 10 patients with clinical diagnosis of uterine sarcoma was made (7 patients under recurrence suspicion and three under initial staging). Mean age was 52.2 yrs. Evolution time after initial diagnosis vary from one month to 15 yrs (median time: 14 months). Lesions were classified as 8 leiomyosarcomas and 2 carcinosarcomas. FIGO staging were establish resulting 5 patients stage I, 1 patient stage III, and 4 patients stage IV. RESULTS: 4 of 7 patients under suspicion of recurrence showed discrepancies between positron emission tomography (PET) and conventional imaging techniques (CIT) information. FDG-PET was negative in three cases of non-conclusive CT. PET was negative in one case with pulmonary metastases. The 3 staging studies were concordant both FDG-PET and CIT images. Pathological information was obtained in 5 cases, and a mean time of 14 months of clinical follow up was made. CONCLUSIONS: FDG-PET can be useful in the follow up of uterine sarcoma patients, and also when it is an incidental finding in other causes hysterectomy.

[SAPHO syndrome]. / Síndrome SAPHO.

We report two cases, one 23 and one 27 year old man, with several years background of sternal and sternoclavicular joints pain, respectively. The laboratory tests were normal. Based on the clinical, radiologic and scintigraphic findings, SAPHO syndrome was diagnosed. Bone scintigraphy makes it possible to obtain a whole body scan in a single whole body scan, and can be used for differential diagnosis of other osteoarticular diseases and for evolutive control and therapeutic response.

[Positron emission tomography with fluordesoxyglucose-F18 in follow-up of endometrial cancer]. / Tomografía de emisión de positrones con fluordesoxiglucosa-F18 en el seguimiento del cáncer de endometrio.

OBJECTIVE: To assess the utility of FDG-PET in the follow-up of patients treated for endometrial cancer and with suspicion of recurrence according to conventional imaging methods (CT, MRI) and/or elevation of serum tumour markers. MATERIALS AND METHODS: Between April 2002 and December 2005, eleven patients underwent 17 FDG-PET studies (six with 2 studies); mean age was 63.4 yrs (range, 52-69 yrs) and time since diagnosis ranged from 11 months to 12 yrs (mean of 56 months). Initially, seven patients were in stage I, three in stage III and one in stage IV (FIGO classification). Histologically, they corresponded to 8 endometrioid carcinomas and 3 non endometrioid carcinomas. RESULTS: FDG-PET showed infradiaphragmatic uptake in 3 patients and disseminated disease in 7 cases. FDG-PET showed no uptake in one patient. CT (n = 7) or MRI (n = 7) detected infradiaphragmatic lesions in 5 patients and visceral lesions in 2. In 11 patients, tumour markers were elevated (CA125, n = 9; CA19.9, n = 2; CA15.3, n = 2). In 7 patients, FDG-PET modified the information yielded by conventional imaging techniques and in 4 patients, the FDG-PET contributed no additional information. In 2 patients, histologic confirmation of the lesions was obtained and in 9 patients, there were clinical follow-up (from 3 to 20 months, mean of 8.7 months) and imaging studies. CONCLUSIONS: FDG-PET is superior to CT and MRI for detecting recurrences in the follow-up of patients with endometrial cancer.

[Early alteration of adrenergic cardiac function in parkinsonisms with Lewy bodies]. / Alteración precoz de la función adrenérgica cardíaca en los parkinsonismos con cuerpos de Lewy.

BACKGROUND: 123I-metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy is clinically used to estimate myocardial sympathetic damage in some forms of heart disease, autonomic nerve disturbance in diabetic neuropathy, and disturbance of the autonomic nervous system in neurodegenerative disease. In the present study, examinations were performed to clarify the rate and characteristics of cardiac sympathetic disturbance in Parkinson's disease (PD) and usefulness of 123I-MIBG myocardial scintigraphy to differentiate PD from the Lewy Body Disease (LBD). MATERIAL AND METHODS: 108 subjects were studied. There were 70 patients with PD, 21 patients with LBD, and 17 age-matched normal subjects without neurological disease. The clinical parameters evaluated were severity of the process (measured by Hoehn and Yahr Scale), vegetative manifestations, development time and use of medication taken. Myocardial adrenergic function was analyzed by imaging with 123I-MIBG. Early (15 min) and delayed (4 h) images of the thorax in the anterior view were obtained after injection of 123I-MIBG (111 MBq). The qualitative and semiquantitative 123I-MIBG uptake was quantified by calculating a heart-to-mediastinum ratio (HMR) and analyzed in a blind manner. RESULTS: The mean H/M ratio in patients with PD and LBD was significantly lower than in controls (p < 0.05). This is independent of development time, process severity, use of medication or vegetative manifestations. The HMR obtained in LBD patients is less clear than in PD. CONCLUSION: 123I-MIBG myocardial scintigraphy might detect early disturbances of the sympathetic nervous system in PD and LBD.