99mTc-tetrofosmin SPECT in solitary pulmonary nodule evaluation.

A correct differential diagnosis between benign and malignant lesions is mandatory in patients with solitary pulmonary nodule (SPN). The aim of the present study was to investigate whether 99mTc-tetrofosmin SPECT may play a role in SPN evaluation. A consecutive series of 111 patients with an uncalcified

The usefulness of neck pinhole SPECT as a complementary tool to planar scintigraphy in primary and secondary hyperparathyroidism.

UNLABELLED: Pinhole SPECT (P-SPECT) has proven to be a high-resolution and sensitive method in both experimental and clinical studies. In this study, we investigated whether P-SPECT combined with conventional planar scintigraphy can give additional information in hyperfunctioning parathyroid gland detection in both primary hyperparathyroidism (pHPT) and secondary hyperparathyroidism (sHPT) since planar imaging has proved partially limited, especially in sHPT. METHODS: We studied 110 consecutive patients with HPT, selecting 67 patients who underwent neck surgery and had definitive histology: 48 with pHPT and 19 with sHPT. All patients underwent planar scintigraphy, (99m)Tc-methoxyisobutylisonitrile ((99m)Tc-MIBI) double-phase scintigraphy (n = 22) or (99m)Tc-tetrofosmin subtraction scintigraphy (n = 45), using a gamma-camera with a parallel-hole collimator. P-SPECT was then performed (180 degrees; matrix size, 128 x 128; zoom factor, 2; time per frame, 40 s) using a tilted detector equipped with a pinhole collimator (insert, 4.45 mm). RESULTS: In the 48 pHPT patients, 49 lesions (43 adenomas, 1 carcinoma, and 5 hyperplastic glands, including 1 intrathyroidal) were found at surgery; in the 19 sHPT patients, 51 lesions (49 hyperplastic glands, including 1 in persistens thymus, and 2 adenomas) were found. P-SPECT proved to be a highly sensitive method, identifying more lesions than planar imaging in both pHPT (97.9% vs. 87.7%) and sHPT (92.1% vs. 78.4%), significantly (P < 0.05) in the latter. P-SPECT, positive in all adenomas, increased planar sensitivity especially in small and light-weight ones, 30.8% of which missed on planar imaging, and also identified a significantly higher number of hyperplastic glands, irrespective of their size. P-SPECT improved image quality and resolution, offering a more correct lesion localization in eutopic and ectopic sites. Neither P-SPECT nor planar imaging had false-positive findings. Moreover, P-SPECT correctly predicted the status found at surgery in 97.9% of pHPT patients and in 82.3% of sHPT patients with multigland disease, whereas planar imaging correctly predicted the status in 89.6% and 58.8%, respectively. P-SPECT was the only positive procedure in 8.9% of all patients, also revealing more lesions in 6% of sHPT patients when both methods were positive. CONCLUSION: P-SPECT appears a highly sensitive, high-resolution method. We suggest its use as a preoperative complementary tool to neck planar scintigraphy, selectively in pHPT patients but extensively in sHPT patients.

The usefulness of single photon emission computerized tomography with pinhole collimator (P-SPECT) in preoperative localization of hyperfunctioning parathyroid glands in patients with secondary hyperparathyroidism.

PURPOSE: In this study the usefulness of parathyroid scintigraphy was evaluated in a group of patients affected by secondary hyperparathyroidism, combining the conventional double-tracer subtraction planar scintigraphy with pinhole-SPECT (P-SPECT) acquisition and comparing the scintigraphic data with those obtained by ultrasonography. MATERIALS AND METHODS: Twenty-four patients with secondary hyperparathyroidism were enrolled, 19 with chronic renal failure on haemodialysis and 5 with renal transplant. All patients underwent parathyroidectomy because of their unresponsiveness to medical therapy and/or severe osteodystrophy. Histology ascertained a single adenoma each in 3 patients and 61 hyperplastic glands in the remaining 21 cases. Before surgery, all patients were submitted to high resolution ultrasonography and afterwards to double-tracer subtraction planar parathyroid scintigraphy ((99m)Tc-pertechnetate/(99m)Tc-tetrofosmin) followed by neck P-SPECT acquisition. RESULTS: P-SPECT was true positive in all 24 patients, while both planar and ultrasonography were false negative in one case. Globally, P-SPECT identified 60/64 hyperfunctioning parathyroid glands, planar 47/64 and ultrasonography 45/64. P-SPECT sensitivity (93.7%) was significantly higher than both planar (73.4%; p<0.001) and ultrasonography (70.3%; p< 0.0005). The difference was also significant (p<0.05) when P-SPECT sensitivity was compared with that obtained combining planar scintigraphy and ultrasonography (84.4%). Moreover, P-SPECT defined the exact number of hyperplastic glands in 85.7% of positive patients, while planar in 60% and ultrasonography in 45%. Only 4 hyperplastic glands were false negative at P-SPECT showing a maximum diameter of 10 mm and a weight ranging from 480 to 500 mg. These glands were also false negative at both planar scintigraphy and ultrasonography which missed further 13 and 15 hyperfunctioning glands, respectively, all detected by P-SPECT. Globally, the latter procedure gave the correct preoperative localization of hyperfunctioning parathyroid glands in 87.5%, planar in 62.5% and ultrasonography in 50%. None of the three procedures had false positive CONCLUSIONS: The data of the present study seem to indicate that P-SPECT is a reliable diagnostic method in preoperative localization of hyperfunctioning parathyroid glands in patients with secondary hyperparathyroidism. This procedure identified a significantly higher number of hyperplastic glands than both double-tracer subtraction planar parathyroid scintigraphy and ultrasonography in our cases, thus proving a more useful guide for the surgeon. Given its low false negative rate, a wider use of P-SPECT is suggested in the preoperative management of patients with secondary hyperparathyroidism undergoing either a first operation of parathyroidectomy or a second operation for recurrence.

Somatostatin receptor scintigraphy with 111In-pentetreotide in non-functioning gastroenteropancreatic neuroendocrine tumors.

To investigate somatostatin receptor scintigraphy (SRS) usefulness compared to conventional imaging procedures (CIP) in non-functioning gastroenteropatic (GEP) neuroendocrine tumors, we studied 40 patients, 30 in follow-up (FU) after previous operation for primary tumor (27 cases) or non-operable for disseminated metastases (3 cases), and 10 in the phase of initial diagnosis and staging (IDS). All patients were asymptomatic for hormone overexpression, with slightly high serum chromogranine A in 6 FU. The definitive diagnosis was obtained by surgery, laparotomy or percutaneous CT/US guided biopsy. Within 1 month before scintigraphy, all patients had undergone at least 2 of 3 CIP (CT, MRI and US); 4 and 24 h after 250 MBq 111In-pentetreotide i.v. injection, whole body scanning, planar and SPECT over the abdomen or other suspect regions were performed. Globally, 135 neoplastic lesions (84 hepatic, 34 abdominal extra-hepatic and 17 extra-abdominal) were ascertained in 32/40 patients; SPECT was positive in 29 cases, CIP in 28 and planar in 20, while all 3 procedures were true negative in the remaining 8 cases. Per patient sensitivity and accuracy were significantly higher at SPECT and CIP than planar. SPECT showed a significantly higher per lesion sensitivity (89.6%) than CIP (72.6%) and planar (53.3%) while CIP sensitivity was significantly higher than planar. SPECT correctly modified CIP patient classification and thus management in 18.7% of patients, while it downstaged the disease in 9.4% in respect of CIP; planar was incorrect in 51.3% of cases. SPECT and CIP combined use achieved 100% accuracy and correctly classified all patients. 111In-pentetreotide SRS, particularly SPECT, is a useful diagnostic tool in the detection of non-functioning GEP tumors, contributing to correct patient classification and appropriate therapeutic strategy. SPECT proved more sensitive than CIP, but their combined use achieved the highest accuracy values and gave the most accurate disease staging.

Mediastinal lymph node involvement in non-small cell lung cancer: evaluation with 99mTc-tetrofosmin SPECT and comparison with CT.

UNLABELLED: In patients with non-small cell lung cancer (NSCLC), surgical resection offers the best chance of cure. The preoperative assessment of mediastinal lymph node involvement is crucial to selecting those patients for whom surgery is indicated. METHODS: To evaluate the possible clinical role of (99m)Tc-tetrofosmin scintigraphy in the presurgical detection of mediastinal node metastases from NSCLC, we performed a prospective comparative study with CT on 83 patients (48 men, 35 women; age range, 38-81 y) with primary NSCLC (36 adenocarcinomas, 39 epidermoid squamous cell carcinomas, and 8 large cell anaplastic carcinomas). They underwent chest SPECT 20 min after (99m)Tc-tetrofosmin injection (740 MBq intravenously). The metastatic involvement of mediastinal nodes was assessed by histologic examination after mediastinoscopy or thoracotomy. Both chest CT and (99m)Tc-tetrofosmin scintigraphy were performed within 2 wk before the surgical staging. RESULTS: Metastatic mediastinal lymph nodes were found in 35 patients. (99m)Tc-Tetrofosmin imaging in assessing the mediastinal involvement yielded a sensitivity of 85.7%, a specificity of 89.6%, and an accuracy of 88.0%; CT results were 68.6%, 75.0%, and 72.3%, respectively. SPECT accuracy was significantly higher than CT accuracy (P < 0.05). However, precise anatomic localization of (99m)Tc-tetrofosmin uptake in the mediastinum was not always present on SPECT images. (99m)Tc-Tetrofosmin SPECT precisely detected the presence or absence of lymph node metastases in 33 of the 36 patients with positive CT findings (enlarged mediastinal nodes with a short axis > or =1 cm), with an accuracy (91.7%) significantly higher (P < 0.05) than that of CT (66.7%). CONCLUSION: (99m)Tc-Tetrofosmin SPECT is a useful presurgical noninvasive method to assess mediastinal lymph node involvement in NSCLC. In particular, it could play a clinical role in reducing the number of invasive staging surgical procedures in selected patients, especially in those with enlarged lymph nodes at CT. Fusing SPECT with CT images could further improve the interpretation of the scintigraphic data.

Somatostatin receptor scintigraphy in liver metastasis detection from gastroenteropancreatic neuroendocrine tumors.

UNLABELLED: In patients with gastroenteropancreatic (GEP) neuroendocrine tumors, we investigated the usefulness of somatostatin receptor scintigraphy (SRS) in the detection of liver metastasis, which represents the most important prognostic factor in these tumors, and in the management of affected patients. METHODS: We enrolled 149 patients with GEP tumors, 69 during initial staging and 80 in follow-up. All patients underwent whole-body scanning at 4 and 24 h, followed by abdominal planar and SPECT imaging after intravenous injection of 250 MBq (111)In-pentetreotide. The patients had previously been submitted to 2 of 3 conventional imaging procedures (CIP), such as CT, MRI, and ultrasound of the abdomen within 1 mo before SRS; on the basis of liver CIP data, the patients had been classified into 3 groups as follows: no evidence of liver metastases, the presence of resectable metastases, or the presence of nonresectable metastases. RESULTS: Liver metastases were histologically proven in 65 cases. SPECT identified malignant lesions in 60 of 65 patients with metastases (sensitivity, 92.3%), planar imaging identified malignant lesions in 38 of 65 patients (sensitivity, 58.5%), and CIP identified malignant lesions in 52 of 65 patients (sensitivity, 80%). Only SPECT demonstrated liver involvement in 13 patients, whereas CIP showed liver involvement in 5 other cases. Moreover, SPECT was significantly more sensitive than planar imaging and CIP in identifying patients with single lesions. Neither SPECT nor planar imaging showed false-positive results in patients with no evidence of liver metastases, including 21 patients with hemangiomas (specificity, 100%), 12 of which were false-positive on CIP (specificity, 85.7%). SPECT per-lesion sensitivity (92.4%) was significantly higher than that of planar imaging (52.4%) and CIP (79.4%). Moreover, SPECT correctly changed patient classification and, thus, management in 28 of 149 patients (18.8%), whereas planar imaging changed classification in 13 patients (8.7%), identifying new or additional metastases not evident on CIP or excluding metastases on CIP of patients with false-positive findings, thus avoiding unnecessary surgery; however, SPECT classification was incorrect in 3.3% of patients, and planar imaging was incorrect in 17.4%. CONCLUSION: (111)In-Pentetreotide SRS is a useful diagnostic tool in the detection of liver metastases in GEP tumor patients. In particular, SPECT proved to be significantly more sensitive and accurate than both planar imaging and CIP. Moreover, SPECT was also the most reliable procedure to obtain correct patient classification, thus guiding the most appropriate therapeutic strategy.

The usefulness of 99mTc-tetrofosmin SPECT in the detection of intrathoracic malignant lesions.

To evaluate the usefulness of 99mTc-tetrofosmin (TF) SPECT in the detection of intrathoracic malignant lesions, we studied 304 patients, 261 with malignant and 43 with benign lesions; 196 of the former had non-treated primary tumors, 193 lung cancer (LC) and 3 mesotheliomas, 11 had LC recurrences and 54 had metastases from different kinds of tumors. Twenty-nine patients with primary tumors were re-checked after chemotherapy or surgery. In all patients, after 740 MBq TF injection, both planar and SPECT images were acquired and analysed qualitatively, SPECT images also semiquantitatively. Scintigraphy was always compared to CT. SPECT showed higher sensitivity, specificity and accuracy values than CT (98.1, 90.7 and 97 vs. 96.2, 81.4, and 93.9%, respectively), their combined use achieving 100% sensitivity and 98.8% accuracy. Planar did not give more information than SPECT, showing a significantly lower sensitivity (63.2%) and accuracy (67.4%). SPECT showed higher accuracy values than CT and planar (86.9 vs. 78.3 and 69.6%) in NSCLC mediastinal lymph node staging. Moreover, SPECT was concordant with CT in correctly evaluating the response to chemotherapy or surgery in all monitorized primary tumors cases, except in one in whom only SPECT detected residual tumor. The semiquantitative analysis added useful information in differentiating malignant from benign lesions and in monitoring the response to chemo-therapy. TF SPECT appears a highly accurate diagnostic method in the detection of intrathoracic malignant lesions, in lungs and pleura, as well as in NSCLC mediastinal lymph node staging and in monitoring treatment effectiveness, playing a complementary role to CT in selected cases.