A meta-iodobenzylguanidine scintigraphic scoring system increases accuracy in the diagnostic management of pheochromocytoma.

As observed by other authors, normal adrenal medullary tissue frequently gives an apparently positive meta-iodobenzylguanidine (MIBG) scan in cases studied using 123I-MIBG and less frequently 131I-MIBG. The aim of this study was to assess the usefulness of a scoring system, based on different uptakes of the radiopharmaceutical, to improve the accuracy of 123I-MIBG scintigraphy in patients with either adrenal or extra-adrenal pheochromocytomas. Charts from 67 consecutive patients (29 males and 38 females, median age 48 years, range 14-80 years) with suspected pheochromocytoma (either sporadic or familial: multiple endocrine neoplasia (MEN) 2a, MEN2b, Von Hippel-Lindau, neurofibromatosis type 1) who underwent 123I-MIBG scintigraphy (scans acquired 4-24 h after injection) from 1991 to 2004, were independently reviewed by two experienced nuclear medicine physicians using liver uptake as a reference (scores: 1, uptake absent or less than the liver; 2, equal to the liver; 3, moderately more intense than the liver; 4, markedly more intense than the liver). Interfering medications were discontinued for the appropriate time before MIBG injection. Histological data were obtained for all patients who underwent adrenalectomy. Scintigraphies were classified as positive using the following criteria: extra-adrenal focal uptake, adrenal enlargement together with non-homogeneous uptake and adrenal uptake more intense than the liver (score 3-4). After surgical resection, as confirmed by histological findings and long-term follow-up (range 1-14 years, average 9.25 years), 43 patients were considered true positives using the proposed scoring system, 20 were true negatives, four were false negatives and none was false positive. In conclusion, the proposed scoring system demonstrated high specificity (100%), sensitivity (91.5%) and accuracy (94%) in the management of pheochromocytoma. Positive predictive value and negative predictive value were 100% and 83.3% respectively. Normal adrenal tissue uptake was correctly discriminated from pheochromocytomas in 18 out of 20 patients, with adrenal uptake equal to the liver (grade 2), using the proposed cut-off level.

Relationship between prognostic factors of breast cancer and 99mTc-sestamibi uptake in patients who underwent scintimammography: Multivariate analysis of causes of false-negative results.

The complementary role of sestamibi scintimammography (SSM) in patients with breast cancer (BC) is well established. The aim of this study was to establish whether a relationship exists between sestamibi uptake, evaluated as a tumour-to-background ratio (TBR), and the main prognostic factors of BC. SSM with the measurement of TBR was performed preoperatively in 102 women (median age 57 years, range 32-81 years) who underwent curative surgery for primary BC. Final pathology showed 4 (3.9%) with pT1a, 17 (16.7%) with pT1b, 44 (43.1%) with pT1c and 37 (36.3%) with pT2 breast carcinomas. The overall sensitivity of SSM was 80.4%. An ANOVA showed significant (P<0.01) differences between the TBR of patients with G1 vs. G3 tumours, and between the TBR of those with G2 vs. G3 breast carcinomas. Moreover, there was a difference (P=0.021) between the TBR of patients (n=12, 11.8%) with CEA serum levels >10 ng/ml (2.031+/-0.420), and those with normal (n=90, 88.2%) CEA values (1.713+/-0.446), whilst no difference (P=NS) was found between patients (n=27, 26.5%) with CA 15-3 >30 U/ml (1.893+/-0.401) and those with normal (n=75, 73.5%) CA 15-3 values (1.699+/-0.462). There was a mild inverse correlation between TBR and both the oestrogen (R=0.25, P=0.011) and the progesterone receptor (R=0.23, P=0.02) rate. The logistic regression analysis showed that only size and CA 15-3 serum levels represent true independent parameters, but the function was able to predict only 11 out of 21 (52.4%) patients with false-negative SSM. TBR is independent of age and mainly correlates with the size of the tumour. There are no reliable preoperative prognostic factors that are really useful for improving SSM sensitivity in patients with small breast carcinomas.

Accuracy of ultrasonography and 99mTc-sestamibi scintimammography for assessing axillary lymph node status in breast cancer patients. A prospective study.

AIMS: The aim of this study was to evaluate the sensitivity, specificity and accuracy of axillary ultrasonography (US) and (99m)Tc-sestamibi scintimammography (SSM) in patients with breast cancer (BC) undergoing curative surgery. METHODS: A series of 77 consecutive women (median age 54 years, range 36-70) with primary BC underwent both US and SSM from 2 to 15 (median 4) days prior to curative surgery. The results of imaging studies were compared against the final pathology. Breast-conserving surgery with axillary node (AN) dissection was performed in 49 (63.6%) patients, and modified radical mastectomy in 28 (36.4%) patients, according to the tumour staging. RESULTS: Final pathology showed 5 pT1bN0, 1 pT1bN1, 28 pT1cN0, 19 pT1cN1, 7 pT2N0, and 17 pT2N1 BC. Overall, 719 AN were removed of which 106 (14.7%) were metastatized nodes (median 3, range 1-5 per patient). The sensitivity, specificity and accuracy were 67.6%, 80.0%, and 74.0% for US, 78.4%, 85.0%, and 81.8% for SSM, and 91.9%, 92.5%, and 92.2% for US and SSM together, respectively. There was a significant difference (p<0.05) in the number of metastatized AN between patients with metastases correctly detected and undetected by both US (3.1+/-1.3 vs. 2.0+/-0.7) and SSM (3.2+/-1.3 vs. 1.7+/-0.7). CONCLUSIONS: Although the results of each diagnostic tests are strictly dependent on the number of the metastatized AN, the combination of axillary US and SSM is a sensitive low-cost procedure that should be suggested in all patients with BC, when a preoperative evaluation of the AN status is required.

Calculating regional tissue volume for hyperthermic isolated limb perfusion: Four methods compared.

INTRODUCTION: Hyperthermic isolated limb perfusion (HILP) can be performed as an alternative to amputation for soft tissue sarcomas and melanomas of the extremities. Melphalan and tumor necrosis factor-alpha are used at a dosage that depends on the volume of the limb. Regional tissue volume is traditionally measured for the purposes of HILP using water displacement volumetry (WDV). Although this technique is considered the gold standard, it is time-consuming and complicated to implement, especially in obese and elderly patients. AIM: The aim of the present study was to compare the different methods described in the literature for calculating regional tissue volume in the HILP setting, and to validate an open source software. METHODS: We reviewed the charts of 22 patients (11 males and 11 females) who had non-disseminated melanoma with in-transit metastases or sarcoma of the lower limb. We calculated the volume of the limb using four different methods: WDV, tape measurements and segmentation of computed tomography images using Osirix and Oncentra Masterplan softwares. RESULTS AND CONCLUSION: The overall comparison provided a concordance correlation coefficient (CCC) of 0.92 for the calculations of whole limb volume. In particular, when Osirix was compared with Oncentra (validated for volume measures and used in radiotherapy), the concordance was near-perfect for the calculation of the whole limb volume (CCC = 0.99). With methods based on CT the user can choose a reliable plane for segmentation purposes. CT-based methods also provides the opportunity to separate the whole limb volume into defined tissue volumes (cortical bone, fat and water).

Hyperfunctioning parathyroid tumours in patients with thyroid nodules. Sensitivity and positive predictive value of high-resolution ultrasonography and 99mTc-sestamibi scintigraphy.

A series of 112 consecutive patients with primary hyperparathyroidism who underwent both high-resolution neck ultrasonography (US) and 99mTc-sestamibi/99mTc-pertechnetate subtraction scintigraphy (SS) prior to successful parathyroidectomy was reviewed. There were 29 (25.9%) men and 83 (74.1%) women, with a median age of 58 years (range 13-78 years). Patients were divided into two groups, according to the preoperative US findings: group A (87 patients, 77.7%) without thyroid diseases, and group B (25 patients, 22.3%) with either multinodular goitre or a solitary nontoxic thyroid nodule. In group B patients partial or total thyroidectomy was also performed, according to the intraoperative findings and frozen-section examination results. Final histopathology showed 99 (88.4%) solitary parathyroid (PT) adenomas and 3 (2.7%) PT carcinomas, while 10 (8.9%) patients had a multiglandular disease. The sensitivity and positive predictive value (PPV) were (group A vs group B) 79.8% vs 70.8% (P=0.25) and 95.7% vs 94.4% (P=0.58) for US, and 83.3% vs 87.0% (P=0.47) and 95.9% vs 90.9% (P=0.32) for SS respectively. Better but similar (P=not significant) results were obtained in patients with solitary PT tumours: 81.5% vs 77.8% (US) and 85.0 vs 94.1% (SS) sensitivity; 97.1% vs 93.3% (US) and 95.8% vs 88.9% (SS) PPV. Overall, the combination of US and SS was 92.9% sensitive (group A=93.1%, group B=92.0%; P=0.55), and the PPV reached 100% in each group. In conclusion, in patients with primary hyperparathyroidism the results of both US and SS are independent of coexistent thyroid disease, especially in patients with solitary PT tumours.

TSH levels and TSH response to TRH as a guide to the replacement treatment of patients with thyroid carcinoma.

Forty-six patients whose thyroid glands had been ablated for thyroid carcinoma, maintained on replacement treatment with triiodothyronine (T3), have been followed by means of serial determinations of pituitary thyrotropin (TSH) levels and of the TSH response to thyrotropin-releasing hormone (TRH), in order to verify the actual dose required to suppress TSH secretion. The treatment was begun with a dose of T3 roughly related to body weight (about 1 mug/kg/day). The daily dose was sequentially adjusted according to the measured TSH levels. The dose of T3 which reduced serum TSH within the normal limits varied from 40 to 120 mug daily. More precisely, it was as low as 40-50 mug daily in five patients and as high as 90-120 mug daily in three patients. The dose, which was given according to their body weights, varied from 0.75 to 1.12 mug/kg/day. TRH administration produced a marked increase of TSH levels in those patients whose TSH was elevated, and varying responses (from no response to a response three times the normal one) in those patients whose TSH was within the normal limits. In the latter group of patients, an increase of the T3 dosage inhibited the TSH response to TRH. These data suggest that, even though 1 mug/kg/day is an adequate T3 dose for the great majority of patients, the extent of TSH suppression is not surely predictable, but must be evaluated case by case by means of serial determinations of TSH levels and of the TSH response to TRH.

Comparison between echocardiographic subtraction method and first-pass radionuclide ventriculography for measuring right ventricular volume after operative "repair" of patients with tetralogy of Fallot.

In the long-term follow-up of patients after repair of tetralogy of Fallot, monitoring right ventricular function is mandatory. The echocardiographic subtraction method proposed by Tomita seems to be easily applicable to a pediatric age population and accurate enough to be included in the longitudinal surveillance of such a group of patients.

Scintigraphic patterns of adrenocortical carcinoma: morpho-functional correlates.

OBJECTIVE: Adrenocortical scintigraphy has demonstrated clinical utility in the morpho-functional characterization of adrenal tumors. The aim of this study was to identify possible relationships between the scintigraphic pattern and endocrine and/or morphological data in a series of adrenocortical carcinomas. DESIGN AND METHODS: Twenty-one patients with adrenocortical carcinoma (11 nonfunctioning and 10 hormone-secreting) were investigated with 75Se-methyl-nor-cholesterol scintigraphy. Clinical, hormonal, radiological, and pathological data were analyzed. RESULTS: The adrenal mass showed no radiocholesterol uptake in 18 cases (11 nonfunctioning and 7 functioning lesions). Contralateral normal adrenal gland was visualized in all patients with nonfunctioning tumors, whereas classic bilateral nonvisualization was observed in the 7 cases with hyperfunctioning masses. Three patients with cortisol-producing carcinomas showed radiotracer uptake by the mass, without visualization of the contralateral gland. At histology, the tumors were shown to be undifferentiated adrenocortical carcinomas; they had an aggressive clinical behavior. CONCLUSIONS: Radiocholesterol scintigraphy has an important role in diagnosing adrenocortical carcinomas, which typically are not visualized. However, 30% of hypersecreting adrenocortical carcinomas show an atypical increased tracer uptake, not predictive of the biochemical and histological features of the tumor.

Advantages of combined technetium-99m-sestamibi scintigraphy and high-resolution ultrasonography in parathyroid localization: comparative study in 91 patients with primary hyperparathyroidism.

OBJECTIVE: To evaluate the usefulness of the combination of Tc-sestamibi/Tc-pertechnetate subtraction scintigraphy (SS) and high-resolution neck ultrasonography (US) in patients with primary hyperparathyroidism (pHPT) undergoing parathyroidectomy. DESIGN AND METHODS: Ninety-one patients with proved pHPT were studied, excluding patients with persistent or recurrent disease. There were 65 (71.4%) women and 26 (28.6%) men, with a median age of 59 years (range 18-78 years). All patients underwent both SS and US prior to surgery, and the results were compared with operative and histological findings. The intraoperative quick-parathyroid hormone assay was available for 52 (57.1%) patients. When multiglandular disease was found, both SS and US were considered truly positive only when at least two enlarged parathyroid (PT) glands had been localized. RESULTS: Eighty-three (91.2%) solitary PT adenomas and three (3.3%) carcinomas were found. Moreover, two (2.2%) patients had a double adenoma and three (3.3%) patients had diffuse PT hyperplasia. The overall sensitivity of combined SS+US was 94.5% (86.8% and 80.4% for SS and US respectively). There was a significant (P<0.05, Student's t-test) difference in size between the PT glands correctly identified and undetected by SS, whereas the site of the removed PT tumors significantly (P<0.05, Fisher exact test) influenced only the US sensitivity. CONCLUSIONS: When the preoperative localization of the PT glands is chosen, the combination of SS and US represents a reliable noninvasive localization technique and should be considered for use in each patient with pHPT undergoing surgery.

99mTc-HMPAO SPECT in the diagnosis of brain death.

OBJECTIVE: To evaluate the effectiveness of single proton emission tomography (SPECT) with 99mTc-HMPAO in the diagnosis of brain death (BD). DESIGN: Prospective study in comatose and brain-dead patients. SETTING: Neurologic ICU. PATIENTS AND METHODS: Fifty comatose patients (age range: 10 days-75 years) were submitted to SPECT study. In 21 of them (42%) reversible factors (e.g., influence of drugs affecting the central nervous system) were present. Thirty-eight patients were clinically brain-dead, while the remaining 12 were tested both in pre-terminal conditions and after the clinical onset of BD. INTERVENTIONS: Brain SPECT following i.v. injection of 99mTc-HMPAO (300-1100 MBq), using a 4-headed gamma-camera (20 min, 360 degrees, 88 images). MEASUREMENTS AND RESULTS: All patients tested in pre-terminal conditions showed preserved brain perfusion. Two of them had flat EEGs despite the absence of any reversible cause of coma; three patients survived, but remained in persistent vegetative states. SPECT confirmed the diagnosis of BD in 45 out of 47 patients (95.7%), clearly showing the arrest of brain perfusion (picture of "empty skull"); in two clinically brain-dead children (aged 10 days and 12 months, respectively) weak perfusion of the basal ganglia, thalamus and/or brain stem was still present, precluding the diagnosis of BD; both of them died a few days later. CONCLUSIONS: Our results confirm the reliability of SPECT in the diagnosis of BD. A problem arises about its effectiveness in brain-dead children, but this seems to be a matter of definition of BD and cerebral viability, rather than a limit of SPECT.

Usefulness of 99m-Tc-sestamibi scintimammography in suspected breast cancer and in axillary lymph node metastases detection.

AIMS: To evaluate the usefulness of 99m-Tc-sestamibi scintimammography (SSM) in the detection of T1-2, N0-1, M0 breast cancer (BC) and axillary node (AN) metastases. PATIENTS AND METHODS: A series of 239 women (median age 55 years) who had already been selected for breast biopsy underwent both mammography (MG) and SSM before surgery. The final diagnosis confirmed in 207 (86.6%) patients, and benign breast lesions in 32 (13.4%). RESULTS: Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MG and SSM in BC detection were 88.9% vs 87.9%, 62.5% vs 93.8% (P<0.01), 93.9% vs 98.9%, 46.5% vs 54.5%, and 85.4% vs 88.7%, respectively. Age did not affect (P=NS) SSM sensitivity, and in premenopausal patients (n=80 (33.5%)) its specificity was 100%. Overall sensitivity and specificity of SSM for assessing AN involvement were 82.3% and 94.1%, respectively. In patients with <3 AN metastases (n=33 (53.2%)) SSM sensitivity was 69.7%, and only one out of six patients with a single AN metastasis had a positive scan. CONCLUSIONS: In patients with suspicious MG undergoing biopsy, SSM should be considered before surgery because of its high specificity, especially in younger patients. At present, its usefulness in detection of AN metastases is still modest and does not allow a correct pre-operative staging of patients with BC.

Sestamibi scintimammography in pT1 breast cancer: alternative or complementary to X-ray mammography?

The aim of this study was to compare the results obtained using X-ray mammography (MG) and 99mTc-sestamibi scintimammography (SSM) in patients with breast lesions < or = 2 cm. One hundred and thirty-four women (median age 52 years, range 32-78), who had already been selected for open breast biopsy, underwent both MG and SSM prior to surgery. Final pathology showed 27 (20.1%) benign breast lesions and 107 (79.9%) breast cancers (pT1a=5 [4.7%], pT1b=50 [46.7%], pT1c=52 [48.6%]). The sensitivity, positive predictive value, negative predictive value and accuracy were 81.3%, 97.6%, 55.6% and 83.6% for SSM and 83.2%, 89.9%, 48.6% and 79.1% for MG, respectively. The results were similar (p=NS), but patients with breast cancer (BC) undetected by MG were significantly (p<0.05) younger than those in which the tumor was correctly diagnosed, while the age did not affect SSM sensitivity. SSM was more (p<0.05) specific than MG in BC detection both in the overall group of patients (92.6% vs 63.0%) and in those with < or = 10 mm breast lesions (94.7% vs 63.2%). In conclusion, in patients with suspected BC sized < or = 2 cm, SSM may help in surgical planning because of its high specificity, and should be considered complementary to MG, especially in younger women.

Assessment of brain perfusion in coma and comparison between SPECT and CT scan data: preliminary report.

In this study we submitted 24 comatose patients (Glasgow Coma Score <8) to Single Photon Emission Tomography (SPECT) during the clinical course of coma to verify its utility and the relationship between SPECT and CT scan data. SPECT was recorded following i.v. injection of Xe-133 in 17 patients and of Tc-99m-HMPAO or Tc-99m-ECD in the remaining 7. SPECT data recorded during the acute phase of coma did not show a clear correlation between cerebral blood flow (CBF) and outcome. SPECT and CT scan detected abnormalities in the same areas in 6 cases (25%); 6 patients (25%) with focal CT-scan lesions showed no focal CBF alterations in the same regions; conversely, in the remaining 12 cases (50%) SPECT disclosed severe perfusion abnormalities where no lesions were detectable on CT-scan. SPECT allowed us to recognize different regional flow patterns, such as absolute or relative hyperemia or oligoemia, which could not be checked with other means, thus improving patient's management. Apart from cerebral ischemia, there was no relationship between lesions on CT-scan and flow pattern. Our preliminary results suggest that SPECT can improve both the knowledge of patient's neurological conditions and management in comparison to the use of only CT scan.

Radionuclide evaluation of lung perfusion after the Fontan procedure.

Lung perfusion was evaluated in 19 patients in whom a Fontan operation had been performed at a mean age of 3.7 years. First pass and equilibrium data were acquired during the lung particle perfusion scan 0.5 to 7.9 years (mean 3.7 years) following the Fontan procedure. Abnormalities of lung perfusion were documented in 8 patients. Minimal underperfusion of small areas of either right or left lung were noted in 4 patients, while the remaining 4 had evidence of major perfusion defects, involving both lungs. The perfusion defects were localized, in the majority of cases, on the side where a palliative procedure had been performed before the Fontan operation: it is of note that all our patients without palliative procedures did not show abnormalities in lung perfusion. Major abnormalities of lung perfusion seemed related to possible intimal thrombosis or emboli due to prolonged polycythemia or to pulmonary vessel distortion due to long-standing shunts.

Technetium-99m sestamibi scintigraphy and helical CT together in patients with primary hyperparathyroidism: a prospective clinical study.

44 consecutive patients with confirmed primary hyperparathyroidism (HPT) undergoing surgery were prospectively enrolled in the study. There were 13 (29.5%) men and 31 (70.5%) women with an overall median age of 59 years (range 23-78 years). Prior to successful parathyroidectomy both (99)Tc(m)-sestamibi/(99)Tc(m)-pertechnetate subtraction scintigraphy (SS) and helical CT were performed, and the results of imaging studies were compared against intraoperative findings. Final histopathology showed 40 (90.9%) solitary parathyroid (PT) adenomata (median size 18 mm, range 8-40 mm), that were in an ectopic location in 13 (32.5%) patients. Moreover, 3 (6.8%) patients had multiglandular disease (one patient with two PT adenomata, two patients with PT hyperplasia), while one (2.3%) patient had a PT carcinoma. The sensitivity and positive predictive value were 86.0% and 97.4% for SS, 88.1% and 94.9% for CT, and 100% and 97.4% for the combination of SS and CT, respectively. Calcium and parathyroid hormone (PTH) serum levels, and the mean size of the removed PT glands of patients with false negative results were lower than that of those with true positive results, but the difference was not significant. Among patients with solitary PT tumours (N=41) the sensitivity was 88.1% and 90.3% for SS and CT-scan, respectively. In conclusion, our study confirms the usefulness of SS, which should be the initial test for patients undergoing parathyroidectomy. However, the strategy of performing two tests in each patient with primary HPT could be of limited utility when the initial SS is positive.

[Nuclear medicine methods for the diagnosis of adrenal tumors]. / Metodiche medico-nucleari per la diagnosi dei tumori surrenalici.

Adrenal scintigraphy using 131I-6-beta-iodomethyl-19-norcholesterol or 6-methyl-75Se-methyl-19-norcholesterol is a function-dependent imaging method which, in association with high-resolution spatial imaging techniques, plays an essential role in the study of adrenocortical hyperfunction. It can distinguish between bilateral cortical hyperplasia and monolateral adenoma or carcinoma and can lateralise the adenoma. In patients with Cushing syndrome, in addition to allowing a distinction to be made between ACTH-dependent forms and independent forms, adrenocortical scintigraphy is particularly appropriate to identify non-common forms of adenomatous hyperplasia. Adrenocortical scintigraphy, performed during dexamethasone administration, is an accurate mean of differentiating bilateral adrenal hyperplasia from monolateral forms (adenoma or carcinoma) in patients with Conn's syndrome. Owing to the gradual spread of high-resolution spatial imaging techniques, the problem of the diagnostic classification of so-called "incidentalomas" (clinically silent masses discovered by chance) is a subject of considerable interest. Adreno-cortical scintigraphy appears to be able to provide an important contribution to identifying the functional behaviour of these tumours. Since the early 80s meta-iodobenzyl-guanidine (MIBG), marked with 131I or 123I, with a structure similar to norepinephrine and characterized by selective tropism for sympathetic and chromaffin tissue, has been used for the scintigraphic study of adrenal medulla. MIBG scintigraphy has been found to be particularly appropriate for the study of intra- and extra-adrenal, single and multiple, benign and malignant pheochromocytomas. This method has a high overall sensitivity and specificity. Lastly, MIBG scintigraphy is useful in the study of neuroblastoma.

Usefulness of CT scan, MRI and radiocholesterol scintigraphy for adrenal imaging in Cushing's syndrome.

The aim of this study was to evaluate the sensitivity and accuracy of computed tomography (CT) scanning, 75Se-selenomethyl-norcholesterol scintigraphy (SNS) and magnetic resonance imaging (MRI) in patients with Cushing's syndrome (CS) undergoing adrenalectomy. A series of 67 patients with CS due to benign adrenal disease was reviewed. There were 11 (16.4%) men and 56 (83.6%) women, with an overall median age of 44 years (range 19-69 years). Prior to surgery all patients underwent both CT and SNS, and 58 (86.6%) underwent adrenal MRI. Thirty-five (52.2%) of the patients (group A) had histologically confirmed unilateral adrenal involvement (33 patients with a solitary adrenocortical adenoma, and two with unilateral nodular cortical hyperplasia), while 32 (47.8%) of the patients (group B) had CS caused by bilateral adrenal involvement, including two patients with multinodular adrenal hyperplasia. The sensitivity, specificity and accuracy of adrenal imaging in group A were 97.1%, 100% and 98.5% for SNS, 94.3%, 68.7% (P<0.05, chi2 test) and 82.1% for CT scan, and 92.3%, 60.0% (P<0.05) and 64.3% (P<0.05) for MRI, respectively. In group B the sensitivity, specificity and accuracy were 100%, 97.2% and 98.5% for SNS, 64.5% (P<0.05), 97.2% and 82.1% for CT scan, and 60.0% (P<0.05), 92.3% and 35.7% (P<0.05) for MRI, respectively. In conclusion, SNS represents the most sensitive and specific adrenal imaging study and should be used in all patients with confirmed biochemical diagnosis of CS undergoing adrenalectomy. The sensitivity and specificity of CT scan and MRI are similar, but the latter shows a lower accuracy, especially in patients with bilateral adrenal involvement.

Non-invasive adrenal imaging in primary aldosteronism. Sensitivity and positive predictive value of radiocholesterol scintigraphy, CT scan and MRI.

The aim of this study was to evaluate the sensitivity and positive predictive value (PPV) of dexamethasone-suppression norcholesterol scintigraphy (NCS), computed tomography (CT) scanning and magnetic resonance imaging (MRI) in patients with primary aldosteronism (PA) who had undergone unilateral adrenalectomy. A series of 49 patients with confirmed PA was reviewed. There were 18 (36.7%) men and 31 (63.3%) women, with a median age of 47 years (range, 23-66 years). NCS was performed in all patients, and 46 (93.9%) and 31 (63.2%) underwent CT scan and MRI, respectively. Final pathology showed an aldosterone-producing adenoma in 45 (91.8%) patients, unilateral nodular cortical hyperplasia (NCH) in two (4.1%) and unilateral microscopic cortical hyperplasia (MCH) in two (4.1%). No aldosterone-producing carcinoma or bilateral adenomas were found. The greatest diameter of the removed adrenal tumour was in the range 8-40 mm (median, 14 mm). The PPV of adrenal imaging was 97.6% for NCS, 85.0% for CT scan (P=0.04) and 83.3% for MRI (P=0.03), and the sensitivity was 85.4%, 85.0% and 74.1%, respectively (P=NS). The age and the main biochemical parameters did not differ significantly (P=NS) between patients with true positive and false negative results of the imaging procedures. NCS accurately depicted all patients with NCH and MCH, whilst CT scan and MRI failed to diagnose such unilateral adrenal gland hyperfunction in two and three patients, respectively. The overall sensitivity of combined NCS and CT scan was 100%. In conclusion, in patients with PA, both NCS and CT scan are necessary to confirm the exclusive unilateral adrenal hyperfunction and, subsequently, to establish the appropriate treatment.

Positive predictive value of 99mTc sestamibi scintimammography in patients with non-palpable, mammographically detected, suspicious, breast lesions.

The purpose of this study was to analyse whether the use of Tc sestamibi scintimammography improves the positive predictive value of X-ray mammography. A series of 73 women (median age 51 years, range 35-79 years) with non-palpable, mammographically suspicious, breast lesions was reviewed. There were 41 (56.2%) pre-menopausal, and 32 (43.8%) post-menopausal women. All patients underwent sestamibi scintimammography prior to open breast biopsy. Definitive histology showed breast cancer (pT1a=1 (1.9%), pT1b=47 (90.4%), pT1c=4 (7.7%)) in 52 (71.2%) patients, and benign breast lesions in 21 (28.8%). Patients with cancer were significantly older (P <0.01), while the greatest dimension (size) of the excised lesion did not differ (8.47+/-1.51 vs 8.30+/-1.53 mm; P =0.66) between the two groups. Overall, the positive predictive values of mammography and sestamibi scintimammography were 71.2% and 95.7%, respectively (P =0.004). Patients with false positive mammography were significantly younger than those in whom cancer was diagnosed correctly (45.35+/-7.56 vs 53.96+/-10.60 years; P =0.001), while age did not affect the sensitivity of sestamibi scintimammography, which reached 100% in patients with breast lesions > or =8 mm in size. In this subgroup the positive predictive value of mammography, sestamibi scintimammography, and mammography+sestamibi scintimammography together were 63.4%, 95.1% (P =0.001), and 97.6%, respectively, and the majority of the patients with benign lesions (13 of 15 (86.7%)) could have avoided biopsy. It is concluded that the use of Tc sestamibi scintimammography in conjunction with mammography may potentially reduce unnecessary surgical procedures, and should be performed in all patients with mammographically suspicious breast lesions of 8 mm or greater in size.

Volterra series modelling and compensation of non-linear distortions caused by susceptibility difference artefacts related to the presence of ferromagnetic implants in magnetic resonance imaging.

Magnetic resonance imaging is popular in medical settings due to its unique technical characteristics. However, its full potential has been limited by imaging artefacts caused by various phenomena. Previously, a methodology was proposed to characterize and reduce artefacts caused specifically by magnetic susceptibility differences. In the present work, the Volterra series approach is suggested as an alternative method for describing non-linear distortions induced by susceptibility artefacts. A second-order Volterra series is utilized for characterizing the image non-linearities using a block-by-block processing approach. Subsequently, a corresponding second-order inverse Volterra series is applied to compensate for the quantified distortions. In addition, a technique for automatic demarcation of recoverable and non-recoverable regions in magnetic resonance images is proposed to ameliorate the developed methodology. Experimental results indicate that this approach offers improved accuracy and flexibility in reducing non-linear distortions caused by magnetic susceptibility artefacts.