Search

Purpose In patients with primary hyperparathyroidism, the preoperative imaging objective is to locate accurately and reliably uniglandular or multiglandular hyperfunctioning parathyroid, to guide surgery, particularly for minimally invasive method. Subtraction planar scintigraphy with dual-isotope (I/Tc-MIBI) is an efficient examination to specify abnormal parathyroid location, but without accurate anatomic reference. This lack should be avoided by a hybrid SPECT/CT image acquisition. Methods We compared planar scans (neck and mediastinum parallel-hole, associated with anterior neck pinhole) to neck and mediastinum SPECT/CT, all with subtraction (I/Tc-MIBI) method, in exact location of abnormal parathyroid in 50 patients with sporadic primary hyperparathyroidism. Surgical and histological findings were used as the standard of comparison. Results Sensitivity is equivalent for the 2 protocols (86% and 75% for SPECT/CT and planar protocol, respectively, P = 0.15), but SPECT/CT was highly specific (specificity 100% and 90% for SPECT/CT and planar protocol, respectively, P = 0.04). In patients with concomitant thyroid disease, subtraction SPECT/CT appeared to be more sensitive than planar protocol (88% and 62% for SPECT/CT and planar protocol, respectively, P = 0.04). Conclusions In preoperative assessment of primary hyperparathyroidism and to guide surgery, we propose to perform first subtraction SPECT/CT and to complete it with neck pinhole, only if tomoscintigraphy is negative.

Osteoblastoma (OB) and osteoid osteoma (OO) are benign bone-forming tumors frequently involving vertebrae and long bones of the extremities. Because of their similar histopathological features, distinction between OB and OO is mostly based on size criteria. CT and MRI represent the cornerstone of noninvasive diagnostic procedures, as they provide excellent morphologic details and often obviate the need for confirmatory biopsy. Bone scan is a complementary, highly sensitive functional technique particularly useful for detection of vertebral OO. F-18 FDG PET/CT could have potentiality in diagnosis and post therapeutic evaluation of patients with OB and OO. We report MRI and dynamic F-18 FDG PET/CT results obtained before radiofrequency or laser ablation from 3 patients with an OB of the right L5 pedicle, an OB of the left talus and an OO of the right acetabulum. Both patients with OB underwent posttherapeutic evaluation to confirm the effectiveness of percutaneous radiofrequency ablation.

Because of its high diagnostic sensitivity in detection of unknown primary tumors, F-18 FDG PET/CT was used in the exploration of a 51-year-old woman presenting with multiple lymphadenopathy of the hepatic hilum and several hepatic and splenic hypodensities on radiologic examinations for which malignancy was suspected. Despite the morphofunctional malignant appearance, both histologic examination and PCR analysis revealed Bartonella henselae infection. Moreover, repeat F-18 FDG PET showed disease regression during focused antibiotic therapy.

In-111 DTPA-D-Phe1-octreotide (In-111 pentetreotide) is a widely used radiotracer for somatostatin receptor (SSTR) in- vestigations in neuroendocrine (NE) pathology. Cellular SSTR den- sity is directly related to the degree of NE cellular differentiation. Poorly differentiated cell lines show a surface reduction of SSTRs, which may lead to misinterpreting the In-111 pentetreotide scintig- raphy results as negative. A case of anorectal small-cell undifferen- tiated neuroendocrine carcinoma is reported. This pathologic finding is rare, highly aggressive, and associated with a dramatic prognosis. The patient was investigated with In-111 pentetreotide SPECT and low-dose computed tomography (CT) for anatomic reference. De- spite its low degree of differentiation, the tumor showed high tracer uptake characterized by a positive incremental trend as shown by comparison of the 4-hour and 24-hour SPECT images, suggesting specific receptorial binding of In-111 pentetreotide.

PURPOSE In patients experiencing colorectal carcinoma, exhaustive analysis of indicates extent of hepatic and pulmonary surgery that prolongs survival of patients. PATIENTS AND METHODS To localize metastasis, we compared 2 F-FDG PET-CT imaging protocols, early respiratory gated scan, and delayed scan, to standard PET imaging procedure. SUVmax and lesion-to-healthy tissue ratio were measured in 60 pulmonary and 21 hepatic lesions by each of the 2 imaging protocols. RESULTS In the liver, metastatic lesion-to-healthy tissue ratios significantly increased on delayed scans as compared with early scans (P < 0.001). Better ratios could not be obtained when using respiratory gated scans, whereas more lesions were detected on delayed scans. In the lungs, metastatic lesion- to-healthy tissue ratio increased significantly on delayed scans for largest lesions (P < 0.001). Ratios were not better when exploring smallest metastatic lesions or when using respiratory gated scans. Factors interfering with F-FDG PET-CT sensitivity are discussed, such as respiratory motion and high FDG physiological uptake in healthy liver parenchyma. CONCLUSIONS Our studies indicate that routine acquisitions should use delayed hepatic scans for all patients referred for evaluation, recurrence check, or monitoring of colorectal adenocarcinoma. Delayed pulmonary scans are useful for the largest metastatic lesions and should be used in addition to early scan. In our experience, respiratory gated scans seem to be less convenient because of a low sensitivity in detection, as compared with the delayed technique; in addition, this technique is currently complicated by some technical issues, although these might be overcome with new gated protocols.

Activated inflammatory cells like neutrophils, macrophages, and lymphocytes have increased F-18 FDG uptake, causing significant tracer accumulation in inflammatory and infectious processes. In this report, we have illustrated F-18 FDG PET/CT features related to systemic sarcoidosis, large-vessel arteritis, abdominal tuberculosis, and pleural aspergillosis in 4 selected patients, who underwent scintigraphic evaluation before and after anti-inflammatory or antibiotic treatment. The evolution of radiotracer uptake intensity reflected the efficacy of medical treatment, permitting either a better modulation of drug dosage or a radical modification of therapeutic strategy. Independently from the cost and access to this type of medical imaging, F-18 FDG PET/CT could have a potential role in assessing treatment efficacy in selected non-neoplastic conditions, allowing morphofunctional cartography of residual inflammatory localizations.

Prognosis of patients with Bartholin’s gland carcinoma(BGC) is strictly related to the nodal stage at diagnosis. Thus, it iscrucial to perform reliable staging for optimal treatment planning. Inspite of wide clinical utilization of F-18 FDG PET in oncologicalroutine, its role in vulvar malignancies is not completely defined. Tokeep organs and preserve anal and ureteral function, a patient withadvanced undifferentiated BGC (FIGO IV-A) received 50 Gy to thewhole pelvis, whole vagina and bilateral inguinal lymph nodes withconcomitant chemotherapy, followed by interstitial brachytherapy.F-18 FDG PET-CT was performed at staging and after treatmentcompletion. Complete regression of the initial metabolic abnormal-ities was shown on posttreatment images, confirming the efficacy ofthe adopted conservative approach. F-18 FDG PET-CT imagingcould have a role in staging and assessing treatment efficacy inaggressive BGC. Key Words: Bartholin’s gland carcinoma, undifferentiatedcarcinoma, F-18 FDG PET, chemoradiation, brachytherapy(