Revista Espa?ola de Medicina Nuclear (English Edition)最新文献

Sentinel node biopsy has become the standard practice for lymph node staging in early stage breast cancer. However, uncertainty remains regarding the best method of radiotracer/dye injection. Currently, the subareolar injection is being widely used because of its technical simplicity and higher rates of SN location versus the so-called deep techniques (peritumoral, intratumoral) that require greater specialization and greater use of resources in the non-palpable lesions.

We present a case of a discrepancy between both techniques that could have caused a false negative.

Objective

To assess the value of intraoperatory radioguided probe detection to guide surgical resection of malignant lesions previously detected by ¹⁸F-FDG PET-CT.

Material

Twelve consecutive patients with suspected tumor recurrence detected by ¹⁸F-FDG PET-CT considered resectable were enrolled in the study. Ultrasound guided fine needle aspiration (FNA) before surgery was performed in 6 patients and CT guided biopsy was performed in 1 patient. In 5 patients with accessible lesions, a radioguided occult lesion localization (ROLL) technique was performed after injection of ^99mTc-colloid (1.7–2.4 mCi) inside the lesion under ultrasound or CT guidance, pre-operatively. Radioguided surgical detection was then carried out 19–24 h afterwards using the gamma probe. In 7 patients with non-accessible needle lesions or multiple lesions, 9.5–10.5 mCi of ¹⁸F-FDG were injected 3–5 h before radioguided surgery using a PET-dedicated probe (Gamma locator DXI-GF&E).

Results

ROLL technique: all lesions injected with nanocolloid were resected (6 lesions in 5 patients, 1 patient with 2 lesions), and recurrence was histologically confirmed. PET probe: fourteen out of 16 hypermetabolic lesions detected on the PET-CT were resected. One cervical and one mediastinal lymph node in different patients could not be excised. Histological recurrence was confirmed in 12 out of 14 lesions. In one patient, the 2 lymph nodes excised were inflammatory.

Conclusions

¹⁸F-FDG PET-CT can be key in deciding surgical approach and appropriate radioguided protocol. When lesions are solitary and easily accessible, ROLL technique seems the method of choice. PET probe is more adequate for less accessible lesions.

Purpose

To evaluate the accuracy of integrated positron emission tomography with ¹⁸F-fluoro-2-deoxy-d-glucose (FDG) and computed tomography (PET/CT) in mediastinal lymph node staging in patients with potentially operable (N2) non-small cell lung cancer (NSCLC) and to ascertain the role of invasive staging in verifying positron emission tomography (PET)/computed tomography (CT) results.

Material and methods

A retrospective study of consecutive patients with pathologically-proven NSCLC and N2 staging by enhanced CT was performed. A PET/CT scan was performed for all the patients. Lymph node staging was pathologically confirmed when it was possible or by consensus in the Thoracic Cancer Committee. Sensitivity, specificity, negative predictive value and positive predictive value of PET/CT in N2 cases were determined.

Results

A total of 34 patients with N2 by CT were evaluated. PET/CT showed N2 in 30 patients. Discrepancies were found in four patients, two patients were classified as N1 in PET/CT and two patients as N0. Lymph node staging was pathologically confirmed in 20 patients. No false positives were found in PET/CT study. Sensitivity was 94.7%, specificity and positive predictive values were 100% and negative predictive value was 50%.

Conclusions

Our data show that integrated PET/CT provides high sensitivity and positive predictive value in mediastinal nodal staging of NSCLC patients. Therefore, in patients with potentially resectable lung cancer, neoadjuvant chemotherapy candidate, mediastinoscopy could be reserved for restaging after induction therapy.

¹⁸F-FDG PET-CT has become an essential tool in oncology patient management. The normal distribution of the FDG and the possible artifacts (pitfalls), including those from CT-based attenuation correction, have already been described in several reviews.

However, only a few cases of FDG focal lung uptake have been reported recently.

We present two cases of oncology patients during a routine follow-up with this type of pitfall, without morphological correlation in the CT scan. We repeated the study in one of them, which made it possible to verify normalization of the hyperuptake, orienting us towards a possible pitfall.

Premature atherosclerosis and its consequent heart disease play a crucial role in patients with systemic lupus erythematosus, even in premenopausal women. It is one of the leading causes of death in long evolution lupus.

We present herewith the case of a 42-year-old premenopausal woman, smoker, with a history of hypertension, cholecystectomy and lupus for 23 years, treated with NSAID, steroids and antimalarial drugs. The patient was consulted due to chest pain on moderate efforts. Due to the suspicion of ischemic heart disease, a cardiology study was initiated, performing a myocardial perfusion SPECT. This revealed an intense and extensive anterolateral perfusion defect, with very light reperfusion in rest images, consistent with the diagnosis of acute infarction in the apical region and ischemia in the territory of the left anterior descending artery, which was later confirmed by cardiac catheterization.

Objective

To evaluate the diagnostic yield of ²⁰¹Thallium SPECT in the detection of local and/or regional lymph node dissemination of pharyngo-laryngeal carcinoma.

Material and methods

29 Patients who had been diagnosed with pharyngo-laryngeal carcinoma were studied (mean age: 60.9 years). These patients had been treated by surgery, chemotherapy and radiotherapy. At between 3 and 6 months after finishing the treatment, all of them underwent a planar and SPECT study at 1 h after the administration of 148 MBq of ²⁰¹Thallium. Uptake was scored on four grades: from 0 (no uptake) to 3 (very intense uptake). The presence or non-presence of lymph nodes with uptake was also evaluated. All the results on the scintigraphy were correlated with long term clinical and radiological follow-up (mean: 2.5 years). The studies were classified as positive for recurrence when the uptake was 2–3 and/or with presence of lymph nodes with uptake.

Results

We obtained 9 true positive, 14 true negative, 3 false positive and 3 false negative results. Sensitivity was 75%, specificity was 82.4%, positive predictive value was 75% and negative predictive value was 82.4%. Two out of three false positives corresponded to the surgical bed uptake and one was attributed to the laterocervical lymph nodes. The three false negatives had grade 1 uptakes, two of them corresponding to pulmonary metastasis without evidence of local recurrence.

Conclusions

The use of ²⁰¹Thallium SPECT in the prognostic evaluation in patients with a treated laryngeal carcinoma shows very acceptable results in the detection of local recurrence and/or regional lymph node dissemination.