Real-time ultrasound virtual navigation in 3D PET/CT volumes for superficial lymph-node evaluation: innovative fusion examination.

OBJECTIVE: To evaluate the feasibility and clinical application of fusion imaging with virtual navigation, combining 18 F-fluorodeoxyglucose (18 F-FDG) positron emission tomography/computed tomography (PET/CT) with real-time ultrasound imaging, in assessing superficial lymph nodes in breast-cancer and gynecological-cancer patients. METHODS: This was a pilot study of breast- and gynecological-cancer patients with abnormal uptake of 18 F-FDG by axillary or groin lymph nodes on PET/CT scan, examined at our institution between January 2017 and May 2019. Fusion imaging was performed, uploading preacquired PET/CT DICOM images onto the ultrasound machine and synchronizing them with real-time ultrasound scanning performed at the lymph-node site. In the first phase, we assessed the feasibility and reliability of fusion imaging in a series of 10 patients with suspicious lymph nodes on both PET/CT and ultrasound, and with full correspondence between both techniques in terms of size, shape and morphology of the lymph nodes (Group A). In the second phase, we included 20 patients with non-corresponding findings between PET/CT and ultrasound: 10 patients with lymph nodes that were suspicious or pathological on PET/CT scan but not suspicious on ultrasound assessment (Group B), and 10 patients with suspicious or pathological lymph nodes on both PET/CT and ultrasound but with no correspondence between the two techniques in terms of number of affected lymph nodes (Group C). RESULTS: In the 30 selected patients, fusion imaging was assessed at 30 lymph-node sites (22 inguinal and eight axillary nodes). In the first phase (Group A), the fusion technique was shown to be feasible in all 10 lymph-node sites evaluated. In the second phase, fusion imaging was completed successfully in nine of 10 cases in Group B and in all 10 cases in Group C. In all groups, fusion imaging was able to identify the target lymph node, guiding the examiner to perform a core-needle aspiration biopsy or to inject radiotracer for selective surgical nodal excision, according to the radio-guided occult lesion localization technique. CONCLUSION: Fusion imaging with virtual navigation, combining PET/CT and real-time ultrasound imaging, is technically feasible and able to detect target lymph nodes even when PET/CT and ultrasound findings are inconsistent. Fusion imaging can also be used to guide the performance of core-needle aspiration biopsy, avoiding further surgical diagnostic procedures, or the injection of radiotracer for selective surgical nodal excision, enabling more sparing, selective surgery. This innovative technique could open up multiple diagnostic and therapeutic opportunities in breast and gynecological oncology. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Prospective multimodal imaging assessment of locally advanced cervical cancer patients administered by chemoradiation followed by radical surgery-the "PRICE" study 2: role of conventional and DW-MRI.

OBJECTIVES: To assess the diagnostic performance of conventional and DW-MRI parameters in the detection of residual tumor in locally advanced cervical cancer (LACC) patients treated with neoadjuvant chemoradiotherapy (nCRT) and radical surgery METHODS: Between October 2010 and June 2014, 88 patients with histologically documented cervical cancer (FIGO stage IB2-IVA) were prospectively included in the study. Maximum tumor diameters (maxTD), tumor volume (TV), DWI signal intensity (SI), and ADCmean were evaluated at MRI after nCRT. Histology was the reference standard. Treatment response was classified as complete (CR) or partial (PR). Comparisons were made with Mann-Whitney, χ2, and Fisher's exact tests. ROC curves were generated for variables to evaluate diagnostic ability to predict PR and to determine the best cutoff value to predict PR. For each diagnostic test, sensitivity, specificity, and accuracy were calculated. RESULTS: TV and maxTD were significantly smaller in the CR than in the PR group (p < 0.001; p = 0.001) and showed, respectively, sensitivity of 68.8%, specificity of 72.5%, and accuracy of 70.5% and of 47.9, 87.5, and 65.9% in predicting PR. High DWI SI was more frequent in the PR (81.8%) than in the CR group (55.3%) (p < 0.009). ADCmean was higher in the CR (1.3 × 10-3 mm2/s, range 0.8-1.6 × 10-3 mm2/s) than in the PR group (1.1 × 10-3 mm2/s; range 0.7-1.8 × 10-3 mm2/s) (p < 0.018). High DWI SI showed sensitivity, specificity, and accuracy of 81.8, 44.7, and 64.6% in predicting PR. The ADCmean measurement increased sensitivity, specificity, and accuracy to 75.0, 76.2, and 75.4%. CONCLUSIONS: Conventional and DW-MRI is useful for predicting PR after nCRT in LACC. The ADCmean value ≤ 1.1 × 10-3 mm2/s was the best cutoff to predict PR. KEY POINTS: • Conventional and DW-MRI is useful for predicting PR after nCRT in LACC. • The combination of T2 sequences, DW-MRI, and the quantitative measurement of ADC mean showed the best results in predicting pathological PR. • The best cutoff for predicting pathological PR was ADCmeanvalue ≤ 1.1 × 10-3 mm2/s.

The PRICE study: The role of conventional and diffusion-weighted magnetic resonance imaging in assessment of locally advanced cervical cancer patients administered by chemoradiation followed by radical surgery.

OBJECTIVES: To analyse the role of DW-MRI in early prediction of pathologically-assessed residual disease in locally-advanced cervical cancer (LACC) treated with neoadjuvant chemoradiotherapy followed by radical surgery. METHODS: Between October 2010-June 2014, 108 women with histologically-proven cervical cancer were screened; 88 were included in this study. Tumour volume (TV) and ADCmean were measured before (baseline-MRI) and after 2 weeks of chemoradiotherapy (early-MRI). According to histopathology, treatment response was classified as complete (CR) or partial (PR). Comparisons were made with Mann-Whitney, Wilcoxon and χ2 tests. ROC curves were generated for statistically significant parameters on univariate analysis. RESULTS: CR and PR were documented in 40 and 48 patients. At baseline-MRI, TV did not differ between groups. At early-MRI, TV was higher in PR than in CR (p=0.001). ΔTV reduction after treatment was lower in PR than in CR (63.6% vs. 81.1%; p=0.001). At baseline-MRI and early-MRI, ADCmean did not differ between PR and CR. ROC curve showed best cut-off for predicting pathological PR was ΔTV reduction of 73% with sensitivity, specificity, accuracy, NPV, PPV of 73%, 72.5%, 72.7%, 76%, 69%. CONCLUSIONS: TV evaluated before and early after treatment could predict pathological response in LACC. ADCmean did not correlate with treatment outcome. KEY POINTS: • Early-MRI tumour volume assessment could predict pathological response to nCRT in LACC. • Best cut-off for predicting pathological PR was ΔTV reduction of 73 %. • Early-MRI ADC mean measurements did not correlate with treatment outcome.

Pancreatic neuroendocrine tumors in MEN1 disease: a mono-centric longitudinal and prognostic study.

PURPOSE: Multiple endocrine neoplasia type 1 (MEN1) is an inherited endocrine neoplastic syndrome associated with a greater risk of endocrine tumor development like pancreatic neuroendocrine tumors (p-NET), with different clinical characteristics from sporadic ones. This paper aims to compare clinical, hystological and morphological aspects of p-NET in patients affected from MEN1 (MEN1+) and not-affected ones (MEN1-). METHODS: We performed a retrospective observational study. Data was collected between December 2010 and December 2015, including patients with a histological diagnosis of p-NET and radiological imaging. We compared clinical, histological, radiological, and prognostic aspects of MEN+ p-NET with MEN-1 p-NET. RESULTS: Of the 45 patients enrolled, 13 MEN1+ and 21 MEN1- cases were analyzed. Frequency of not secreting p-NETs and insulin secreting p-NETs, histopathological grades and Ki67 expression were superimposable between MEN1+ and MEN1- patients. MEN1+ pNETs are more often multicentric compared to MEN1- pNETs. Frequency of liver and nodes metastatic spread was higher in MEN1- p-NET compared to MEN1+ p-NET. Analyzing p-NET according to the disease outcome, we found that recovered and stable p-NETs in MEN1+ patients, compared to MEN1- cases, are diagnosed at lower age (p = 0.04/p = 0.002) and that are more frequently multifocal lesions (p = 0.009/p = 0.002). CONCLUSIONS: In our study pNETs in MEN1+ and pNETs in MEN1- don't significantly differ for prognosis but only for clinical features. p-NET stage disease and prognosis can be positively influenced by early diagnosis and screening in index patients' first-degree relatives.

PRospective Imaging of CErvical cancer and neoadjuvant treatment (PRICE) study: role of ultrasound to predict partial response in locally advanced cervical cancer patients undergoing chemoradiation and radical surgery.

OBJECTIVE: Chemoradiation-based neoadjuvant treatment followed by radical surgery is an alternative therapeutic strategy for locally advanced cervical cancer (LACC), but ultrasound variables used to predict partial response to neoadjuvant treatment are not well defined. Our goal was to analyze prospectively the potential role of transvaginal ultrasound in early prediction of partial pathological response, assessed in terms of residual disease at histology, in a large, single-institution series of LACC patients triaged to neoadjuvant treatment followed by radical surgery. METHODS: Between October 2010 and June 2014, we screened 108 women with histologically documented LACC Stage IB2-IVA, of whom 88 were included in the final analysis. Tumor volume, three-dimensional (3D) power Doppler indices and contrast parameters were obtained before (baseline examination) and after 2 weeks of treatment. The pathological response was defined as complete (absence of any residual tumor after treatment) or partial (microscopic and/or macroscopic residual tumor at pathological examination). Complete-response and partial-response groups were compared and receiver-operating characteristics (ROC) curves were generated for ultrasound variables that were statistically significant on univariate analysis to evaluate their diagnostic ability to predict partial pathological response. RESULTS: There was a complete pathological response to neoadjuvant therapy in 40 (45.5%) patients and a partial response in 48 (54.5%). At baseline examination, tumor volume did not differ between the two groups. However, after 2 weeks of neoadjuvant treatment, the tumor volume was significantly greater in patients with partial response than it was in those with complete response (P = 0.019). Among the 3D vascular indices, the vascularization index (VI) was significantly lower in the partial-response compared with the complete-response group, both before and after 2 weeks of treatment (P = 0.037 and P = 0.024, respectively). At baseline examination in the contrast analysis, women with partial response had lower tumor peak enhancement (PE) as well as lower tumor wash-in rate (WiR) and longer tumor rise time (RT) compared with complete responders (P = 0.006, P = 0.003, P = 0.038, respectively). There was no difference in terms of contrast parameters after 2 weeks of treatment. ROC-curve analysis of baseline parameters showed that the best cut-offs for predicting partial pathological response were 41.5% for VI (sensitivity, 63.6%; specificity, 66.7%); 16123.5 auxiliary units for tumor PE (sensitivity, 47.9%; specificity, 84.2%); 7.8 s for tumor RT (sensitivity, 68.8%; specificity, 57.9%); and 4902 for tumor WiR (sensitivity, 77.1%; specificity, 60.5%). ROC curves of parameters after 2 weeks of treatment showed that the best cut-off for predicting partial pathological response was 18.1 cm3 for tumor volume (sensitivity, 70.8%; specificity 60.0%) and 39.5% for VI (sensitivity; 62.5%; specificity, 73.5%). CONCLUSIONS: Ultrasound and contrast parameters differ between LACC patients with complete response and those with partial response before and after 2 weeks of neoadjuvant treatment. However, neither ultrasound parameters before treatment nor those after 2 weeks of treatment had cut-off values with acceptable sensitivity and specificity for predicting partial pathological response to neoadjuvant therapy. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

PRospective Imaging of CErvical cancer and neoadjuvant treatment (PRICE) study: role of ultrasound to assess residual tumor in locally advanced cervical cancer patients undergoing chemoradiation and radical surgery.

OBJECTIVE: To determine the diagnostic performance of two-dimensional (2D) ultrasound parameters, three-dimensional (3D) power Doppler and contrast-enhanced indices in detecting residual disease in locally advanced cervical cancer patients triaged to neoadjuvant treatment followed by radical surgery. METHODS: Between October 2010 and June 2014, we screened 108 women with histologically documented locally advanced cervical cancer Stage IB2-IVA, of whom 88 were included in the final analysis. 2D ultrasound parameters, 3D power Doppler and contrast-ultrasound parameters were assessed 5 weeks after the end of neoadjuvant chemoradiation therapy. The pathological response was defined as complete (absence of any residual tumor after treatment) or partial (including microscopic and/or macroscopic residual tumor at pathology examination). The two response groups were compared and receiver-operating characteristics (ROC) curves generated to determine the best cut-off value of sonographic tumor diameter to predict residual disease. Histology was considered as reference. RESULTS: Complete pathological response to chemoradiation was observed in 40 (45.5%) patients and partial response in 48 (54.5%). The presence of residual disease, as confirmed at pathology examination, was detected by 2D grayscale ultrasound with a sensitivity of 64.6% and specificity of 65%. Color Doppler examination in the cases with lesions visualized on grayscale imaging detected the presence of residual disease, confirmed at pathology, with a sensitivity of 87.1% and specificity of 21.4%. The best area under the ROC curve (0.817) was for the detection of pathological residual disease of at least 6 mm in diameter, using a cut-off value of 12 mm for the largest tumor diameter assessed using 2D grayscale ultrasound (sensitivity, 95%; specificity, 70.6%). Neither 3D vascular indices nor contrast-ultrasound parameters obtained for lesions suspected at ultrasound following chemoradiation differed significantly between patients with histological complete and those with partial response. CONCLUSIONS: Our results show that grayscale and color Doppler ultrasound have a low level of diagnostic performance in detecting residual disease after neoadjuvant chemoradiation in patients with locally advanced cervical cancer. The best performance was achieved in detection of macroscopic (≥ 6 mm) residual disease. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Groin sentinel node biopsy and 18F-FDG PET/CT-supported preoperative lymph node assessment in cN0 patients with vulvar cancer currently unfit for minimally invasive inguinal surgery: The GroSNaPET study.

OBJECTIVE: The study aims were: 1) to verify the role of sentinel node biopsy (SNB) in a subset of patients with clinical N0 (cN0) invasive vulvar cancer (VC) who were still candidates for radical inguinal surgery according to the current guidelines; 2) to investigate whether a preoperative 18F-FDG PET/CT (PET/CT) evaluation could improve the selection of node negative patients. METHODS: From July 2013 to July 2016, all patients with VC admitted to our Division were evaluated by standard imaging and clinical exam. Among the patients assessed as cN0 we enrolled those unsuitable for SNB, due to: T > 4 cm, multifocal tumors, complete tumor diagnostic excision, contralateral nodal involvement and local recurrence. A preoperative PET/CT was performed. For each patient surgery included SNB, performed using a combined technique (radiotracer plus blue dye), followed by standard inguino-femoral lymphadenectomy. The reference standard was histopathology. RESULTS: Forty-seven patients entered the study for a total of 73 groins. Histopathology revealed 12 metastatic SNs in 9 groins. No false negative SNs were found (NPV 100%). PET/CT showed a negative predictive value of 93%. CONCLUSIONS: Our data suggest that SNB is accurate and safe even in cN0 patients currently excluded from this procedure, providing that a careful preoperative selection is performed. PET/CT allows a reliable assessment of LN status and may be an effective support for the selection of patients who are safe candidates for SNB.

Somatostatin receptor positron emission tomography/computed tomography imaging in Merkel cell carcinoma.

BACKGROUND: Merkel cell carcinoma (MCC) is an uncommon aggressive primary cutaneous carcinoma with neuroendocrine differentiation. However, literature data about the use of somatostatin receptor positron emission tomography/computed tomography (PET/CT) imaging in MCC are limited and its role is not clearly stated. OBJECTIVE: To investigate the role of PET/CT using somatostatin analogues radiolabelled with gallium-68 in patients with MCC. METHODS: All patients affected by MCC who performed a somatostatin receptor PET/CT imaging from October 2007 to May 2014 were retrospectively analysed. The diagnostic performances of PET/CT were evaluated on a patient-based analysis and compared to final diagnosis (histology = 3 or clinical/radiological follow-up = 20). RESULTS: We evaluated 23 consecutive MCC patients [18 men; median age 71 years (range 47-87)]. Primary tumour was located in ear (1/23), cheek (3/23), arm (2/23), hand (1/23), back (1/23), anal canal (1/23), gluteus (4/23), thigh (3/23) and popliteal fossa (1/23). In 6/23 patients, the site of primary tumour was unknown. PET/CT was performed to detect primary tumour site (4/23) or to stage (8/23) or re-stage (11/23) patients. PET/CT resulted positive in 14/23 patients and according to the final diagnosis was defined true positive, true negative, false positive (FP) and false negative in 11/23, 8/23, 3/23 and 1/23 cases respectively. FP PET/CT results were due to unspecific liver uptake, post-surgical inflammation and pancreatic neuroendocrine tumour. PET/CT was unable to detect primary tumour site in all patients with unknown primary MCC. Sensitivity, specificity and diagnostic accuracy of PET/CT were 92%, 73% and 83% respectively. CONCLUSIONS: In our experience, somatostatin receptor PET/CT imaging resulted useful in patients with MCC and presented high diagnostic performances with a significant impact in disease management although in patients with unknown primary MCC, it was unable to identify the primary tumour site.

Comparison of metaiodobenzylguanidine scintigraphy with positron emission tomography in the diagnostic work-up of pheochromocytoma and paraganglioma: a systematic review.

AIM: The aim of this paper was to systematically review published data about the comparison of radiolabelled metaiodobenzylguanidine (MIBG) scintigraphy and positron emission tomography (PET) with different radiopharmaceuticals in patients with pheochromocytoma and paraganglioma (Pheo/PGL). METHODS: A comprehensive literature search of studies published in PubMed/MEDLINE and Embase databases through September 2012 and regarding MIBG scintigraphy and PET imaging with different radiopharmaceuticals in patients with Pheo/PGL was carried out. RESULTS: Twenty-eight studies comprising 852 patients who underwent both MIBG scintigraphy and PET or PET/CT with different radiopharmaceuticals were included and discussed. Three studies evaluated carbon-11-hydroxyephedrine ([11C]HED) as PET radiopharmaceutical, nine studies fluorine-18-dopamine ([18F]DA), eight studies fluorine-18-dihydroxyphenylalanine ([18F]DOPA), twelve studies fluorine-18-fluorodeoxyglucose ([18F]FDG) and five studies gallium-68-somatostatin analogues. CONCLUSIONS: Despite the heterogeneity of the studies included in the analysis, it can be concluded that the diagnostic performance of PET with various agents is clearly superior to that of MIBG scintigraphy in patients with Pheo/PGL, mainly for familial, extra-adrenal and metastatic diseases; however, MIBG maintains a unique role in selecting patients suitable for 131I-MBG therapy. Further larger prospective studies comparing MIBG and different PET tracers in patients with Pheo/PGL as well as a cost-effectiveness analysis of the two techniques are needed.

Pharmacological interference with 123I-metaiodobenzylguanidine: a limitation to developing cardiac innervation imaging in clinical practice?

BACKGROUND: (123)I-metaiodo-benzylguanidine (MIBG) scintigraphy is considered a valid imaging test to evaluate the cardiac sympathetic nervous system. However, scientific literature showed that some drugs are able to or are expected to interfere with MIBG uptake. Thirty years after introduction of the method and over 15 years since the appearance of the first document on pharmacological interference with MIBG, an update on this issue has become necessary. AIM: The aims of this review paper are: (1) to identify the pharmacological basis of interference of a variety of substances with MIBG uptake; and (2) to update the list of drugs that definitely interfere with MIBG on the grounds of evidence in the literature. MATERIALS AND METHODS: A MEDLINE search was conducted. Scientific studies, case report and review articles were collected. Papers published demonstrating drugs interfering with MIBG uptake were evaluated. RESULTS: Drugs may interact with MIBG uptake by 5 mechanism: (1) type-1 uptake inhibition; (2) inhibition of active transport to vesicles; (3) competition in transport to vesicles; (4) depletion of neurosecretory vesicle content; (5) calcium-mediated mechanism. We find that drugs like cocaine, antidepressants, some antipsychotic, tramadol, labetalol, sympatho-mimetics, reserpine and some calcium antagonists (as diltiazem, verapamil and nifedipine) do interfere with MIBG uptake. On the other hand, we find that controversial data are available on scientific literature regarding digoxin and amiodarone. CONCLUSIONS: A compiled statement of MIBG interfering medicines is now recommended to help nuclear medicine physicians in clinical practice to avoid potential pitfalls and improve the efficacy of (123)I-MIBG scintigraphy as a diagnostic tool.

Role of (18)F-FDG PET-CT in head and neck squamous cell carcinoma.

The role of PET-CT imaging in head and neck squamous cell carcinoma during pre-treatment staging, radiotherapy planning, treatment response assessment and post-therapy follow-up is reviewed with focus on current evidence, controversial issues and future clinical applications. In staging, the role of (18)F-FDG PET-CT is well recognized for detecting cervical nodal involvement as well as for exclusion of distant metastases and synchronous primary tumours. In the evaluation of treatment response, the high negative predictive value of (18)F-FDG PET-CT performed at least 8 weeks from the end of radio-chemotherapy allows prevention of unnecessary diagnostic invasive procedures and neck dissection in many patients, with a significant impact on clinical outcome. On the other hand, in this setting, the low positive predictive value due to possible post-radiation inflammation findings requires special care before making a clinical decision. Controversial data are currently available on the role of PET imaging during the course of radio-chemotherapy. The prognostic role of (18)F-FDG PET-CT imaging in head and neck squamous cell carcinoma is recently emerging, in addition to the utility of this technique in evaluation of the tumour volume for planning radiation therapy. Additionally, new PET radiopharmaceuticals could provide considerable information on specific tumour characteristics, thus overcoming the limitations of (18)F-FDG.

Clinical significance of incidental focal colorectal (18)F-fluorodeoxyglucose uptake: our experience and a review of the literature.

AIM: The aims of the present study were: (i) to evaluate the focal incidental colorectal uptake of (18)F-fluorodeoxyglucose ([(18)F]FDG) and to correlate it with colonoscopy and histological findings; (ii) to evaluate the relationship between the presence/absence of neoplastic disease and clinical data and the anatomical site of [(18)F]FDG uptake; and (iii) to compare our results with those reported for incidental colorectal uptake of [(18)F]FDG in the literature and those obtained from various screening programmes for colorectal cancer. METHOD: The database of 6000 patients referred for [(18)F]FDG positron emission tomography/computed tomography (PET-CT) to our centre was retrospectively reviewed for incidental colorectal uptake of [(18)F]FDG. Patients with focal uptake were selected and the aetiology of PET findings was verified with a subsequent colonoscopy and histopathological analysis when available. RESULTS: Incidental colorectal uptake of [(18)F]FDG was seen in 144 (2.4%) patients, of whom 64 (1.1%) had focal uptake; 48 out of these 64 patients underwent colonoscopy, which showed malignant tumours in 12 (25%), premalignant lesions in 19 (40%), non-neoplastic lesions in six (12%) and lesions not confirmed by colonoscopy in 11 (23%). Our data agreed with previously published data. Statistical analysis did not show any significant relationship between the presence/absence of neoplastic disease and patient sex or age, type of primary disease and anatomical site of [(18)F]FDG uptake. Comparing our data with various screening programmes, a significant difference was found only with series in which colonoscopy was performed in patients at high risk for colorectal cancer. CONCLUSION: Focal incidental colorectal uptake of [(18)F]FDG is observed in about 1% of PET/CT studies and carries a high risk of neoplastic disease. A PET-CT report should suggest colonoscopy when abnormal findings are reported.

An unusual case of adrenal metastasis from colorectal cancer: computed tomography and fluorine 18-fluoro-deoxy-glucose positron emission tomography-computed tomography features and literature review.

Incidentally discovered adrenal masses are a common diagnostic problem. While computed tomography (CT) and magnetic resonance (MR) imaging can adequately characterize most benign or malignant adrenal masses, in some cases the results are indeterminate. We report and discuss a case of an adrenal metastasis with misleading clinical and CT features, in which an abnormal metabolic uptake detected through fluorine 18-fluoro-deoxy-glucose positron emission tomography ((18)F-FDG PET)-CT raised the suspicion of adrenal metastasis relatively early compared with apparently normal results on repeated follow-up CT examinations.

The evolution in the use of MIBG in more than 25 years of experimental and clinical applications.

Radioiodinated metaiodobenzylguanidine (MIBG), or Iobenguane, was developed in the late 1970s at the Michigan University Medical Center for imaging the adrenal medulla and its diseases, and was rapidly extended to depict a wide range of tumors of neural crest origin. Because of its high and selective uptake and retention by these tumors, careful consideration was also given to the therapeutic potential of [(131)I]MIBG. Beside imaging and therapy of neuroendocrine tumors, the possibility of in vivo assessment of cardiac sympathetic neuronal activity led recently to a renewed interest for MIBG scintigraphy and this application is still expanding. In this paper, we review the evolution in the use of MIBG in more than 25 years of experimental and clinical applications, with attention also to the developments in radiochemistry and instrumentation. A literature search in PubMed based on ''metaiodobenzylguanidine or MIBG'' was conducted; from this analysis, it appears that the use of MIBG evolved from nearly exclusively oncology (both for diagnosis and therapy) to new applications mainly aimed to study the sympathetic neuronal integrity of the heart. Those currently exceed those about imaging of tumor diseases. We also report the geographic distribution of published papers.

Impact of 111In-DTPA-octreotide SPECT/CT fusion images in the management of neuroendocrine tumours.

PURPOSE: Somatostatin receptor scintigraphy with [(111)In]-diethylene triamine pentaacetate acid (DTPA)-octreotide is an accurate method for detecting neuroendocrine tumours (NETs) but often does not provide clear anatomical localisation of lesions. The aim of this study was to assess the clinical usefulness of anatomical-functional image fusion. MATERIALS AND METHODS: Fifty-four patients with known or suspected NET were included in the study. Planar and single-photon-emission computed tomography (SPECT) imaging was performed using a dual-head gamma camera equipped with an integrated X-ray transmission system, and the images were first interpreted alone by two nuclear medicine physicians and then compared with SPECT/CT fusion images together with a radiologist. The improvement provided by SPECT/CT in the interpretation of SPECT data alone and any modification in patient management were recorded. RESULTS: Fusion images improved SPECT interpretation in 23 cases, providing precise anatomical localisation of increased tracer uptake in 20 cases and disease exclusion in sites of physiological uptake in 5. In 10 patients, SPECT/CT allowed definition of the functional significance of lesions detected by diagnostic CT. SPECT/CT data modified clinical management in 14 cases by changing the diagnostic approach in 8 and the therapeutic modality in 6. CONCLUSIONS: Our study demonstrates that image fusion is clearly superior to SPECT alone, allowing precise localisation of lesions and reducing false-positive results.

Role of PET in medullary thyroid carcinoma.

In the diagnostic assessment of medullary thyroid carcinoma (MTC), nuclear medicine imaging provides its contribution mainly in the postoperative work-up to detect residual or recurrent tumor. With respect to scintigraphy with gamma-emitter radiopharmaceuticals, positron emission tomography (PET) offers interesting perspectives owing to its higher image quality, spatial resolution and speed. Moreover, the recent developments of hybrid machines allow to obtain images that simultaneously hold both anatomic (computed tomography) and functional (PET) information with great impact on diagnostic efficacy. (18)F-fluoro-deoxyglucose ((18)F-FDG) is the most frequently used PET tracer in oncology. Preliminary reports of FDG-PET in MTC patients show encouraging results with a higher sensitivity in detecting local recurrent and metastatic disease when compared with single photon emission tracers. However, (18)F-FDG uptake depends on lesion size and to some extent on the grade of differentiation and biologic aggressiveness of the tumor; so FDG-PET seems useful mainly in patients with very high calcitonin levels and high progression rate. Like other neuroendocrine tumors, MTC is characterized by the presence of amine uptake mechanism and/or peptide receptors at the cell membrane allowing the clinical use of specific radiopharmaceuticals that reflect the different metabolic pathways of MTC, and in particular the synthesis, storage and release of hormones ((18)F-dihydroxyphenilalanine, (18)F-DOPA and (18)F-fluorodopamine, (18)F-FDA) and the expression of receptors ((68)Ga-labeled somatostatin analogs). These tracers are currently under investigation and will further improve the diagnostic approach of MTC.

Clinical significance of focal and diffuse thyroid diseases identified by (18)F-fluorodeoxyglucose positron emission tomography.

(18)F-Fluorodeoxyglucose positron emission tomography (FDG-PET) thyroid incidentalomas are defined abnormal FDG uptake in the thyroid gland found at PET scan performed as part of a staging protocol and follow-up of patients with various kinds of malignancies. In the present study we report two cases of FDG PET thyroid incidentalomas, and review the literature with regard to the meaning of this new category of thyroid "disease". Since the advent of whole body FDG PET scan, a relatively high incidence of cases of thyroid FDG uptake has been reported as an incidental finding as in one of our patient. Focal uptake was found to be more likely associated to a malignant lesion, while a diffuse thyroid uptake to a benign thyroid disease. However, differential diagnosis is difficult, and reported data in literature are somewhat discordant. A focal thyroid uptake of FDG incidentally discovered at PET scan cannot be invariably considered a malignant thyroid nodule, however a prompt and complete work-up including laboratory examinations, ultrasonography and fine needle aspiration cytology, should be obtained to exclude a thyroid carcinoma. On the other hand, patients with a PET finding of diffuse FDG uptake can be considered at low risk of malignancy, being more likely associated to chronic thyroiditis or diffuse thyroid autonomy.

Evaluation of the surgical completeness after total thyroidectomy for differentiated thyroid carcinoma.

BACKGROUND: To quantify the rate of patients without thyroid remnants, to identify predictive factors for the absence of residual thyroid tissue and to evaluate number, site, size and function of thyroid remnants after total thyroidectomy for differentiated thyroid carcinoma (DTC). METHODS: Thousand one hundred and seventy-eight patients who underwent total thyroidectomy for DTC were evaluated; 343 patients with lymph node or distant metastases and 115 patients with detectable thyroglobulin autoantibodies (TgAb) were excluded. (131)I ablative treatment (RAI) without preliminary diagnostic (131)I whole body scans (DxWBS), and 24-h (131)I quantitative neck uptake (RAIU test) and thyroglobulin (Tg) off L-T4 evaluation were performed in the remaining 720 pts. In 252 patients a 99mTc-pertechnetate pre-operative thyroid scan (99mTc-scan) was used for comparison with (131)I neck scans after RAI to evaluate site of thyroid remnants. Only patients with thyroid remnants were evaluated for successful ablation 6-10 months after RAI. RESULTS: Post-treatment whole body scan (TxWBS) demonstrated lack of thyroid remnants in 50/720 patients and the best predictive factors for the absence of residual thyroid tissue were RAIU <1% and undetectable Tg off L-T4. Thyroid remnants were present in 670/720 patients. In 252 patients with (99m)Tc-scan, 617 sites of functioning thyroid tissue were found: 381 within and 236 outside the thyroid bed. Complete successful ablation was achieved in 610/670 patients with thyroid remnants. CONCLUSIONS: This study confirms that most patients (93.1%) have thyroid remnant after total thyroidectomy for DTC. Most thyroid remnants were contralateral to tumour site and were even observed outside thyroid bed. However, a real total thyroidectomy, demonstrated by negative TxWBS, RAIU <1% and undetectable Tg off L-T4, was achieved in 6.9% of patients.

Solitary liver metastasis from Hürthle cell thyroid cancer: a case report and review of the literature.

Metastasis to the liver from thyroid cancer is a rare event with a reported frequency of 0.5%. Metastatic liver involvement from differentiated thyroid cancer (DTC) is nearly always multiple or diffuse and usually found along with other distant metastases (lung, bone and brain). The authors describe a patient with a solitary liver metastasis from Hürthle cell thyroid cancer, which appeared during long-term follow-up. The lesion was diagnosed by progressive increase of thyroglobulin in the serum and imaged with I-131 whole body scan, ultrasonography, magnetic resonance imaging (MRI) and F-18 fluoro-deoxyglucose positron emission tomography (FDG-PET) scan. For patients with a Tg level above some arbitrary limit, the administration of a large dose (3.7-5.5 GBq; 100-150 mCi) of I-131, in order to obtain a highly sensitive Tx whole body scan (WBS), remains the best diagnostic strategy. However, on very rare occasions, physiological enteric radioactivity can hide possible abdominal lesions and further indepth studies, such as FDG-PET scans, are sometimes necessary.

[New perspectives in diagnosis and therapy of endocrine gastroenteropancreatic (GEP) tumors with somatostatin analogues]. / Nuove prospettive nella diagnosi e terapia dei tumori endocrini gastroenteropancreatici (GEP) con analoghi della somatostatina.

In the last decade important progresses have been obtained in the diagnosis and therapy of endocrine gastroenteropancreatic (GEP) tumors, mainly derived from the somatostatin receptors characterization and the introduction of long acting somatostatin analogues. Receptorial scintigraphy with radio-labeled analogues (Octreoscan) is the first choice investigation for staging and follow-up of endocrine GEP tumors, thanks to the high sensitivity in revealing the primary tumor and metastases, and for its capability to reveal lesions that are not identified by other imaging methods. Moreover, somatostatin analogues uptake by tumors allow us to use radiopharmaceutical compounds for advanced disease treatment. Between the radio-labeled drugs until now studied, interesting results have been obtained by DOTA-lanreotide (MAURITIUS), DOTA0 Tyr3-octreotide (DOTATOC) and DOTA0 Tyr3-octreotate, bound to beta-emitting radio-isotope suitable for therapeutic use. In the field of the pharmacological therapy of GEP tumors, the clinical trials show that somatostatin analogues reduce the symptoms related to functionally active tumors and stabilize or slow tumor growth improving the patient quality of life. Although somatostatin analogues alone could not be able to cure GEP tumors, their early utilization in association with surgical debulking of primary tumor and metastases, embolization or chemoembolization, and interferon, chemotherapy and radio-metabolic therapy (mainly directed to the destruction of micrometastases), increases the possibility of a radical therapeutic intervention. The continuous evolution of pharmacological research provides always new analogues (octreotide LAR, lanreotide, vapreotide, BIM-23244, BN 81644, PTR-3173, BIM-23A387, SOM-230, etc.) with different pharmacokinetic and receptorial properties and acting with more effectiveness in the different individual clinical situations. In this context there have been recently introduced also the "chimeric" analogues. On the other hand, the widespread utilization of molecular biology and immunohistochemical methods can allow, in perspective, to better define the receptorial pattern of individual endocrine tumors, after their surgical removal. The necessity to integrate endocrinological, nuclear medicine, surgical, oncologic and laboratory competencies behaves a multidisciplinary approach based on the utilization of diagnostic-therapeutic protocols supplying comparable results. It does not appear unjustified to expect, in the future, a scenery of more "individual" and more effective therapies for patients affected by GEP tumours.