OBJECTIVES: 18F-choline positron emission tomography (PET)/computed tomography (CT) is an integral part in restaging of patients with prostate cancer (PC). The aim of this study was to describe the whole-body physiologic distribution of 18F-choline and to discuss some abnormal sites of uptake not related to PC we observed. MATERIALS AND METHODS: Eighty consecutive patients submitted to 18F-choline PET/CT imaging for primary staging or biochemical recurrence (prostate specific antigen rising) after treatment of PC was considered. Whole-body PET/CT was acquired approximately 40 min after 18F-choline injection. RESULTS: We observed physiological 18F-choline uptake in liver, pancreas, spleen, salivary and lachrymal glands and also, owing to renal excretion, in urinary tract. Other sites of less intense tracer uptake were bone marrow and intestines. We found abnormal and unexpected PET findings in 15 patients (18.7%), not owing to PC localizations. The majority of these findings were owing to inflammation (12 of 15); a case of low grade lymphoma was detected; two patients showed focal brain uptake of 18F-choline and were subsequently submitted to magnetic resonance: in one a meningioma and in the other a low-grade brain tumour were diagnosed. CONCLUSION: Accurate knowledge of the biodistribution of 18F-choline is essential for the correct interpretation of PET/CT imaging. CT enables differentiation of physiological bowel activity and 18F-choline excretion in the ureters. In our series, 18F-choline uptake in benign pathological conditions mainly included sites of inflammation; nevertheless, accumulation in tumour deposits not because PC cannot be excluded, particularly in the brain, where correlative imaging with magnetic resonance is of the utmost importance.

PURPOSE: The aim of our prospective study was to compare the diagnostic accuracy of early, delayed and dual-time-point positron emission tomography (PET) acquisition with contrast enhanced computed tomography (CT) within a PET-CT examination in the evaluation of pulmonary solitary nodules (SPNs). MATERIALS AND METHODS: Thirty patients were enrolled in the study. All the patients underwent a dual-time-point PET-CT examination. Whole-body PET images were acquired at 50 min after fluorine18-fluorodeoxyglucose ((18)F-FDG) administration (early), followed by a chest acquisition (delayed). Lung nodules with maximum standardised uptake value SUVmax > or =2.5 were considered malignant. SUVmax was calculated on early and delayed images; SUV increasing > or =10% (Delta SUVmax) was considered suggestive of malignancy. Absence of significant lung nodule enhancement (<15 Delta HU) at CT was considered strongly predictive of benignity. For the CT morphological assessment, the irregularity of the shape of each lesion was rated. PET-CT results were related to histological assays and clinical records. Diagnostic accuracy was assessed by area under the receiveroperarting characteristic (ROC) curves analysis. RESULTS: Early and delayed SUVmax of malignant nodules were significantly higher than those of benign disease. Early SUVmax sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 77%, 91%, 79.5% and 66.7%; delayed SUVmax corresponding values were 77%, 66%, 74% and 66%; dual-time-point SUVmax values were 83%, 67%, 75% and 74%; DeltaHU values were 94%, 34%, 67%, 96%; CT morphologic evaluation values were 61%, 46%, 60%, 47%. Area under the curve (AUC) for early SUVmax was 0.79, for delayed SUVmax 0.80, for dual-time-point SUVmax 0.85, for DeltaHU 0.63 and for CT morphologic assessment 0.58. CONCLUSIONS: In our small series of patients, early and delayed SUVmax showed comparable accuracies, whereas morphological and contrast enhanced CT evaluations showed the lowest accuracies. Dual-time-point SUVmax showed the largest AUC. However, dual-time-point SUVmax was most sensitive, whereas single-time-point SUVmax was most specific.

Our aim was to evaluate the role of SPECT/CT for the diagnosis of diabetic foot infection by labeled leukocytes. METHODS: Seventeen patients with 19 clinically suspected sites of infection were included. After leukocyte labeling and administration, planar scans were acquired at 30 min, 4 h, and 24 h for 18 consecutive patients. SPECT/CT was obtained at 6 h. The final diagnosis was established by clinical follow-up (24 mo) in all cases and by bone biopsy for 14 sites. RESULTS: Leukocyte scanning was positive in 16 of 19 lesions and negative in 3. SPECT/CT changed the interpretation of the planar and SPECT images for 10 of 19 suspected sites (52.6%): it excluded osteomyelitis in 6 cases, revealed bone infection in 1 case, and revealed both bone and soft-tissue infection in 3 cases. The hybrid device did not significantly contribute to the evaluation of patients with negative scan results. CONCLUSION: SPECT/CT can be useful for a more accurate diagnosis of diabetic foot infection by labeled leukocyte imaging.

PURPOSE: The aim of this study was to compare the diagnostic accuracy of 2-[fluorine-18] fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG-PET) and computed tomography (CT) with PET/CT in the detection of liver metastases during tumour staging in patients suffering from colorectal carcinoma for the purposes of correct surgical planning and follow-up. MATERIALS AND METHODS: A total of 467 patients underwent a PET/CT scan using an iodinated contrast medium. We compared images obtained by the single PET scan, the single CT scan and by the fusion of the two procedures (PET/CT). The final diagnosis was obtained by histological examination and/or by the follow-up of all patients, including those who did not undergo surgery or biopsy. RESULTS: The PET scan had 94.05% sensitivity, 91.60% specificity and 93.36% accuracy; the CT scan had 91.07% sensitivity, 95.42% specificity and 92.29% accuracy. The combined procedures (PET/CT) had the following values: sensitivity 97.92%, specificity 97.71% and accuracy 97.86%. CONCLUSIONS: This study indicates that PET/CT is very useful in staging and restaging patients suffering from colorectal cancer. It was particularly useful when recurrences could not be visualised either clinically or by imaging despite increasing tumour markers, as it guaranteed an earlier diagnosis. PET/CT not only provides high diagnostic performance in terms of sensitivity and specificity, enabling modification of patient treatment, but it is also a unique, high-profile procedure that can produce cost savings.

BACKGROUND: Ductal intraepitelial neoplasia (DIN) represents a spectrum of disease that may progress from usual hyperplasia to ductal carcinoma in situ (DCIS) grade 3. The aim of the study was to asses the correlation between the DIN classification and the surgical treatment including sentinel lymph node biopsy (SLNB). PATIENTS AND METHODS: In this retrospective study, 229 patients with DIN had undergone conservative or radical surgical treatment and SLNB in cases of DIN1C-DIN3. RESULTS: Breast conservative surgery was the definitive treatment in 80% of the cases. The H&E evaluation of excised sentinel nodes was negative for metastatic disease; nevertheless the immunohistochemical (IHC) evaluation revealed the presence of metastatic cells in 6 patients (3.7%). CONCLUSION: In cases of DIN lesions SLNB is not indicated. The only reason SLNB should be considered is when there is an evidence of invasive foci at definitive histology or when radical mastectomy is proposed.

BACKGROUND: We evaluated the value of single-photon emission computed tomography/computed tomography (SPECT/CT) with a hybrid camera for (99m)Tc-tetrofosmin (TF) imaging of brain tumors and metastases after radiotherapy. METHODS: Forty (40) patients (27 with primary brain tumors and 13 with intracranial metastases) were examined 6 months after radiation therapy. SPECT images were first evaluated alone and then reinterpreted by adding the anatomic (CT) data. Tumor-to-background ratio values were calculated in the nonattenuation-corrected (T1/B1) and in the CT-attenuation-corrected (T2/B2) images. Scintigraphic results were compared with clinical follow-up. RESULTS: SPECT was true positive for viable tumor tissue in 21 patients and negative in 19. SPECT/CT contributed in 10 of 40 patients (25%): It improved the visualization of lesions in the deep temporal lobe, in the orbital region, and in the posterior fossa. SPECT/CT was useful in 4 of 8 patients with suspicion of radionecrosis. The hybrid camera did not significantly contribute both in patients with a negative scan or with large frontotemporal tumors. When all the lesions were considered, no significant difference was found between T1/B1 and T2/B2. In small lesions (<2 cm), T2/B2 was significantly higher (p = 0.04) than T1/B1. When the clinical outcome was considered, patients with a significant SPECT/CT contribution had a longer average survival than patients with a positive scan, in which the hybrid camera did not provide any substantial information (13.3 vs. 8.2 months; p = 0.0007). CONCLUSIONS: Hybrid SPECT/CT can be useful to better characterize small lesions that are deeply located and in areas of high physiologic background. Further studies and larger series are needed to more accurately define the potential clinical impact of hybrid imaging in patients' management.

The aim of this study was to analyze the effect of acute vestibular deficit on the cerebral cortex and its correlation with clinical signs and symptoms. Eight right-handed patients affected by vestibular neuritis, a purely peripheral vestibular lesion, underwent two brain single photon emission computed tomography (SPECT) in 1 month. The first SPECT analysis revealed reduced blood flow in the temporal frontal area of the right hemisphere in seven of eight patients, independent of the right/left location of the lesion. The alteration was present always in the right, non-dominant hemisphere and was reversible in some patients 1 month after the onset, together with attenuation of signs and symptoms. It may be hypothesized that the transient reduction of cortical blood flow and subsequently of cortical activity in the non-dominant hemisphere, also the expression of cerebral plasticity, may serve as a defense mechanism aimed to attenuate the vertigo symptom.

Cranial osteomyelitis is a potentially fatal lesion. White blood cell scanning (WBC) with 99mTc-hexamethylpropylene amine oxime (HMPAO) has proven highly sensitive and specific in the diagnosis and follow-up of patients with suspected osteomyelitis. In this report we show the usefulness of SPECT and transmission CT performed simultaneously using a hybrid imaging device for the functional anatomic mapping of soft tissue and cranial bone infections. 99mTc-HMPAO-labeled leukocytes scintigraphy was performed on an elderly diabetic man with an intracranial mass lesion and with suspected temporal bone infection. Planar scans were acquired 30 min, 4 h, and 24 h after injection. SPECT/CT was obtained 6 h after tracer injection, using a dual-head camera coupled with a low-power X-ray tube. The scintigraphic results were matched with the results of surgery and of clinical follow-up. The planar images alone were true-positives for abscess in this patient. SPECT/CT improves the accuracy of99mTc-HMPAO scintigraphy especially in discriminating between soft-tissue and bone involvement. In fact, SPECT/CT also showed temporal bone osteomyelitis. This result indicates that SPECT/CT performed using a hybrid device can improve imaging with 99mTc-HMPAO-labeled leukocytes in patients with suspected osteomyelitis by providing accurate anatomic localization and precise definition of the extent of infection.

Early diagnosis of osteomyelitis and prosthetic bone infection is essential for successful therapy and prevention of complications. Nuclear medicine offers a variety of modalities for this aim, including both single photon emission tomography (SPET) and positron emission tomography (PET) radiopharmaceuticals. The main limitation of these functional images is the fact that they are lacking the structural delineation of the pathologic processes; this important drawback can sometimes render interpretation difficult and diminish the diagnostic capability. The recent availability of hybrid SPET/computed tomography (CT) and PET/CT devices that acquire both functional and anatomical data can solve these problems. In fact, the combination of SPET or PET with CT provides exact anatomical registration with bone and joint lesions and improves the accuracy of the nuclear medicine images. This article reviews the currently available literature and addresses the use of hybrid systems in the diagnosis of osteomyelitis and prosthetic bone infection. The first reports indicate that hybrid imaging is very useful in these indications, because it is able to provide further information of clinical value in several cases. The advantage of accurately localizing the areas of increased radiotracer uptake allows a precise differentiation between soft tissue and bone infection, that is crucial for the choice of therapy and patients' management. However, data are still very limited and further studies are needed to verify if hybrid imaging may really become clinically relevant in the near future for early diagnosis of osteomyelitis and prosthetic bone infection.

AIM: Lower gastrointestinal (GI) hemorrhage is a complex clinical problem that requires disciplined evaluation for successful management. This study was conducted to evaluate the applicability of single photon emission computed tomography/computed tomography (SPECT/CT) in patients with acute lower gastrointestinal bleeding undergoing scintigraphy with 99mTc-labelled red blood cells (RBC), and to assess the additional clinical value of fused images when compared to the standard radionuclide scan. METHODS: Twenty-seven patients presenting with acute lower GI tract hemorrhage were studied with conventional dynamic and planar 99mTc-RBC imaging. In 19 patients with positive findings on scans taken within 6 hours, a SPECT/CT study was immediately performed using a hybrid system composed of a dual-head, variable angle gamma camera and an X-ray tube. The number of patients in whom SPECT/CT changed the scintigraphic interpretation with regard to the presence or site of GI blood loss as confirmed by other diagnostic or therapeutical procedures was recorded. RESULTS: Image fusion was easy and successful in all patients showing perfect correspondence between SPECT and CT data and allowing precise anatomical localization of the sites of 99mTc-RBC extravasation. SPECT/CT had significant impact on the scintigraphic results in 7/19 patients (36.8%): in 6 patients it precisely localized the bleeding foci whose location could not be identified in standard scans and in one it excluded the presence of an active GI hemorrhage. CONCLUSIONS: SPECT/CT with a hybrid system is feasible and useful for facilitating imaging interpretation and improving the accuracy of 99mTc-RBC scintigraphy in patients with acute lower GI bleeding.

Atherosclerosis is a systemic disease of the vessel wall that mainly affects medium- and large-sized arteries, and accounts for 50% of all deaths in western countries. Imaging of atheromatous plaques has traditionally centered on assessing the degree of luminal narrowing. More recently it has become clear that it is of the utmost importance to identify the vulnerable atherosclerotic plaques responsible for the majority of life-threatening syndromes. Molecular imaging using nuclear medicine techniques such as single-photon emission computed tomography (SPECT) and positron emission tomography (PET), has the potential to characterize the activity of atheromas. In the present review we summarize the results of radionuclide imaging in the detection of vulnerable atherosclerotic lesions.

BACKGROUND: To assess the accuracy of whole-body MR imaging (WB-MRI) in comparison with whole-body [18(F)]-2-fluoro-2-deoxy-D-glucose (FDG) PET-CT in staging patients with diagnosed colorectal carcinoma (CRC). METHODS: Twenty consecutive patients with previously diagnosed CRC underwent WB-MRI (3T) and PET-CT for staging of lymph node (N) and distant metastases (M). Evaluation was done according to the American Joint Committee on Cancer Staging Criteria. MR images were evaluated by two radiologists while PET-CT images by one radiologist and one nuclear medicine physician. Histology and/or a clinical follow-up of 3-6 months served as standard of reference. RESULTS: Lymph node involvement was determined in 10/20 cases as N-positive in WB-MRI and in 15/20 in PET-CT. M-stage was evaluated for liver metastases (27 lesions in 15 patients with WB-MRI, 23/15 patients with PET-CT), lung (19/5 patients with WB-MRI, 25/7 patients with PET-CT), and bone (9/3 patients with WB-MRI, 9/3 patients with PET-CT). Two patients showed peritoneal implants and three patients demonstrated local recurrence at the surgery site on both modalities. No brain metastases were found. CONCLUSIONS: WB-MRI is a feasible method for examining colon cancer patients but cannot displace the present role of PET-CT.

Procedure guidelines for scintigraphic detection of sentinel node in breast cancer are presented.

Anti-CD20 monoclonal antibodies (mAbs), unlabeled rituximab (Rituxan, Biogen Idec Inc., Cambridge, MA; and Genentech Inc., South San Francisco, CA) or radiolabeled 90Y-ibritumomab (Zevalin, Biogen Idec Inc., Cambridge, MA) and 131I-tositumomab (Bexxar; Glaxo Smith Kline, Research Triangle Park, NC), have proven to be effective therapy for non-Hodgkin's lymphoma (NHL), but also induce immediate and persistent decreases in normal peripheral blood lymphocytes (PBLs). Lym-1, a mAb that selectively targets malignant lymphocytes, also has induced therapeutic responses and prolonged survival in patients with NHL when labeled with iodine-131 (131I). We have retrospectively examined its effect on PBLs in 41 NHL patients that had received 131I-Lym-1 therapy. Absolute lymphocyte counts (ALCs) were evaluated before and after the first and last 131I-Lym-1 infusion. Modest decreases in PBLs were observed in most of the patients. Using strict criteria to define recovery, time to recovery was determined for 19 patients, with the remainder censored because of insufficient follow-up (median follow up for censored patients: 22 days). Using Kaplan-Meier estimates, it would be predicted that 31% of patients would recover by 28 days and that median time to recovery would be 44 days after the last 131I-Lym-1 infusion. No predictors were found for time to recovery, considering such factors as the administered Lym-1 or 131I dose, spleen volume, or radiation doses to the body, marrow, or spleen. The data suggest that the effect of 131I-Lym-1 on ALC is the result of a nonspecific radiation effect, rather than a specific Lym-1 mAb effect. The shorter time required for ALC recovery after 131I-Lym-1 when compared to that reported for anti-CD20 mAbs, whether radiolabeled or otherwise, is probably related to differing mechanisms for lymphocytotoxicity and lesser Lym-1 antigenic density on normal B-lymphocytes.

Scintimair mography is a molecular breast imaging technique using tumour-seeking radiopharmaceuticals; with standard gamma-cameras, is proved of value especially when mammography is indeterminate and in women with dense breasts; nevertheless, this technique shows a high sensitivity only for cancers >1 cm. The issue of detecting small cancers is critical for the future development and clinical usefulness of breast imaging with radiopharmaceuticals, because other modalities are increasingly employed for early identification of small abnormalities. The use of high-resolution dedicated cameras for breast imaging is the best option to improve small cancers' detection: they allow greater flexibility in patient positioning, and the availability of projections similar to those of mammography. Moreover, the detector can be placed directly against the breast, and a mild compression is possible, with the results of reducing breast thickness, increasing the target-to-background ratio and the sensitivity. Our first clinical findings using the dedicased camera Lumagem 3200S (Gamma Medica, Inc., Northridge, USA) are very satisfactory. Till now, 29 patients with BI-RADS category III and IV lesions </=1 cm were prospectively evaluated using a conventional gamma-camera and the dedicated device. Four out nine (44%) of the malignant lesions were detected with the standard gamma-camera, whereas the high-resolution camera visualized all the breast cancers. The standard gamma-camera and the dedicated one showed the same specificity: 19 out of 20 (95%) benign lesions were negative. Our results indicate that molecular breast imaging with this dedicated camera is able to detect small cancers in patients with probably benign or low-suspicion to indeterminate mammographic findings.

PURPOSE: This study was done to analyse the additional morphological and functional information provided by the integration of [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography ([18F]-FDG-PET) with contrast-enhanced multidetector computed tomography (MDCT) in the characterisation of indeterminate solitary pulmonary nodules (SPNs). MATERIALS AND METHODS: Fifty-six SPNs, previously classified as indeterminate, were evaluated using a Discovery ST16 PET/CT system (GE Medical Systems) with nonionic iodinated contrast material and [18F]-FDG as a positron emitter. Images were evaluated on a dedicated workstation. Semiquantitative parameters of [18F]-FDG uptake and morphological, volumetric and densitometric parameters before and after contrast administration were analysed. Results were correlated with the histological and follow-up findings. RESULTS: Twenty-six SPNs were malignant and 30 were benign. Malignant lesions at both PET/CT and histology had a mean diameter of 1.8+/-1.2 cm, a volume doubling time (DT) of 222 days, a mean standardized uptake value (SUV) of 4.7 versus 1.08 in benign lesions and a mean postcontrast enhancement of 44.8 HU as opposed to 4.8 HU in benign nodules. Malignant lesions had a significantly shorter doubling time and significantly greater postcontrast enhancement compared with benign nodules. Based on the SUV and using a cut-off value of >2.5, PET/CT had a sensitivity of 76.9%, specificity of 100%, diagnostic accuracy of 89.2%, positive predictive value (PPV) of 100% and negative predictive value (NPV) of 83.3%. Based on doubling time (cut off<400 days), it had a sensitivity of 76.9%, specificity of 93.3%, accuracy of 85.7%, PPV of 90.9% and NPV of 82.3%. Based on postcontrast enhancement (cut off>15 HU), it had a sensitivity of 92.3%, specificity of 100%, accuracy of 96.4%, PPV of 100% and NPV of 93.7%. CONCLUSION: PET/CT allows accurate analysis of anatomical/morphological and metabolic/functional correlations of SPN, providing useful data for identifying and locating the disease, for differentiating between malignant and benign nodules and for establishing the aggressiveness and degree of vascularity of pulmonary lesions. Therefore, partly in view of the considerable reduction in time and cost of the single examinations, we believe that PET/CT will gain an increasingly dominant role in the diagnostic and therapeutic approach to lung cancer, especially in the preclinical phase.

BACKGROUND: Planar scintimammography is useful for characterizing breast lesions >10 mm. Our aim was to evaluate Tc-99m sestamibi scintimammography with a hybrid (SPECTICT) device for functional anatomical mapping (FAM). PATIENTS AND METHODS: Three planar images and a chest SPECT/CT were performed with a hybrid device in 53 patients with mammographically suspicious lesions. The final histopathological diagnosis was obtained after surgery. RESULTS: The planar images were positive in 27 out of 37 carcinomas (sensitivity 73%) and the SPECT/CT in 33 (sensitivity 89.2%). The sensitivity of planar imaging and SPECT/CT was 42.9% and 71.4% in cancers < or =10 mm, and 91.3%, and 100% in cancers >10 mm, respectively. The specificity was 93.8% for both planar and SPECT/CT imaging; accuracy was 79.2% for planar scans and 90.6% for SPECT/CT. FAM was useful in providing a precise anatomical localisation of the SPECT findings. CONCLUSION: SPECT/CT scintimammography using a hybrid device is able to detect breast cancer, showing a sensitivity higher than that of planar images, especially for small cancers.