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Expansion in blood volume (BV) is a well-recognized response to arterial underfilling secondary to impaired cardiac output in heart failure (HF). However, the effectiveness of this response in terms of outcomes remains inadequately understood. Prospective analysis was undertaken in 110 patients with HF hospitalized and treated for fluid overload. BVs were measured in a compensated state at the hospital discharge using the indicator-dilution methodology. Data were analyzed for composite 1-year HF-related mortality/first rehospitalization. Despite uniform standard of care, marked heterogeneity in BVs was identified across the cohort. The cohort was stratified by BV expansion greater than or equal to +25% above normal (51% of cohort), mild-moderate expansion (22%), and normal BV (27%). Kaplan-Meier (K-M) survival estimates and regression analyses revealed BV expansion (greater than or equal to +25%) to be associated with better event-free survival relative to normal BV (

Findings from heart failure (HF) studies linking diuresis-related weight loss to clinical decongestion and outcomes are mixed. Differential responses of interstitial and intravascular volume compartments to diuretic therapy and heterogeneity in volume profiles may confound the clinical interpretation of weight loss in patients with HF.Data were prospectively collected in hospitalized patients requiring diuresis. Plasma volume (PV) was measured using I-131-labelled albumin indicator-dilution methodology. The cohort was stratified by tertiles of weight loss and analyzed for interstitial fluid loss relative to changes in PV and HF-related morality or first rehospitalization. Among 92 patients, the admission PV was expanded +42% (4.7 ± 1.2 L) above normal with significant variability (14% normal PV, 18% mild-moderate expansion, and 68% with large PV expansion [+25% above normal]). With diuresis there were proportional decreases in interstitial volume (-6.5 ± 4.4%) and PV (-7.5 ± 11%); however, absolute decreases in the PV (-254 mL, interquartile range -11 to -583 mL) were less than 10% of interstitial volume loss (-5040 mL, interquartile range -2800 to -7989 mL); greater interstitial fluid loss did not translate into better outcomes (log-rank P = .430).Diuresis-related decreases in weight reflect fluid loss from the interstitial compartment with only minor changes in the PV and without an impact on outcomes. Further, the degree of PV expansion at hospital admission does not drive the magnitude of the diuresis response, even with a wide spectrum of body weights; interstitial fluid overload is preferentially targeted and PV relatively preserved. Therefore, greater interstitial fluid loss reflects clinical decongestion, but not better outcomes, and a limited association with intravascular volume profiles potentially confounding weight loss as a prognostic metric in HF.

Background Although volume overload is a commonly described clinical feature of advanced heart failure (HF), less is known regarding volume profiles of patients with less severe class I and II HF. Methods Intravascular volume was quantitated by radiolabeled-albumin indicator-dilution technique in clinic outpatients. Results Forty-six patients (age 61 ± 13years, left ventricular ejection fraction 30 ± 8%) were prospectively evaluated with 28 undergoing repeat evaluations at 1 year. There was no difference in averaged total blood volume (TBV) at baseline between class I (N = 26) and II (N = 20) patients (5.6 ± 1.6vs 6.0 ± 1.3 L, P = .368) and at 1-year of follow-up. However, there was marked heterogeneity in plasma volume (–13% to +69% of normal) and red cell mass (RBCM –31% to +50%) profiles with TBV expansion identified in 46% of the cohort, whereas only 48% had a normal TBV. RBCM deficit (true anemia) was common (39%), but a low hemoglobin concentration was accurate in identifying anemia in only 11% of the cohort. RBCM excess (polycythemia) also was identified in 20% of the cohort. Conclusions Marked heterogeneity in plasma volume and RBCM volume profiles is present even in mild HF, and identifying volume overload, which was common in early HF, has the potential to help guide therapy in the reduction of HF progression. Intravascular volume as a modifiable risk factor in early HF warrants further study.

Background:The role of coronary microvascular disease and its impact on functional and energetic reserve in heart failure with preserved ejection fraction (HFpEF) remains unclear. We hypothesized that in response to submaximal pharmacologic stress (dobutamine), patients with HFpEF have impairment in left ventricular (LV) myocardial mechanical (external work [EW]), energetic (myocardial O2consumption [MVO2]), and myocardial blood flow (MBF) reserve. We further assessed whether coupling of MBF to EW is impaired in HFpEF and associated with compensatory increases or pathological decreases in myocardial O2extraction. Lastly, we assessed whether coupling of MVO2to EW (mechanical efficiency) was impaired in HFpEF.Methods and Results:In prospectively enrolled patients with HFpEF (n=19) and age/sex-matched healthy controls (n=19), we performed11C-acetate positron emission tomography assessing MVO2and MBF at rest and during dobutamine infusion. EW was calculated as stroke volume (echo)×end-systolic pressure×heart rate. At rest, compared with controls, patients with HFpEF had higher LV EW, MVO2, and MBF. With dobutamine, LV EW, MVO2, and MBF increased in both HFpEF and controls; however, the magnitude of increases was significantly smaller in HFpEF. In both groups, MBF increased in relation to EW, but in HFpEF, the slope of the relationship was significantly smaller than in controls. Myocardial O2extraction was increased in HFpEF. Mechanical efficiency was similar in HFpEF and controls. In a post hoc analysis, HFpEF patients with LV hypertrophy (n=10) had significant reductions in LV mechanical efficiency relative to controls.Conclusions:In HFpEF during submaximal dobutamine stress, there is myocardial mechanical-, energetic- and flow-reserve dysfunction with impaired coupling of blood flow to demand and slight increases in myocardial O2extraction. These findings provide evidence that coronary microvascular dysfunction is present in HFpEF, limits O2supply relative to demand, and is associated with reserve dysfunction.

BACKGROUND AND PURPOSE SISCOM and STATISCOM were clinically proved to be effective for ictal/inter-ictal single-photon emission computed tomography (SPECT) analysis coregistered with magnetic resonance imaging (MRI) for seizure localization. Recently, a software package also became available for this analysis. This study aimed to investigate and compare the performance of these analysis methods for seizure localization. METHODS A total of 378 patients who underwent 99m Tc-ethyl cysteinate dimer (ECD) SPECT scans were retrospectively reviewed and 28 remained after applying exclusion criteria. Their SPECT and MRI images were analyzed with SISCOM (with z-score of 1.5 and 2), STATISCOM, and MIMneuro, resulting in a total of 112 image data sets. Two experienced radiologists participated in the blind review process using a custom tool and they can mark up to two hyper- and/or hypoperfusion regions. Their review results were analyzed using the Jackknife Free Response Receiver-Operating Characteristics (JAFROC) test and the JAFROC figure-of-merit (FoM) was reported for each method. The interobserver agreement was also assessed using Cohen's kappa test. RESULTS Based on the readers' two choices, averaged FoM was 85.7%, 83.9%, 66.1%, and 51.8% for STATISCOM, MIMneuro, SISCOM (z-score = 2), and SISCOM (z-score = 1.5), respectively. The average confidence rating was 2.5, 2.3, 1.6, and 1.1 for STATISCOM, MIMneuro, SISCOM (z-score = 2), and SISCOM (z-score = 1.5), respectively. For interobserver agreement, kappa was .742 for STATISCOM, .816 for MIMneuro, .517 for SISCOM (z-score = 2), and .441 for SISCOM (z-score = 1.5; all P < .001). CONCLUSION Our study demonstrated that STATISCOM showed the best performance for seizure localization, which was closely followed by MIMneuro. In addition, MIMneuro was not inferior to SISCOM with either z-score.

We previously developed an operator-interactive method for the measurement of left ventricular (LV) and right ventricular (RV) ejection fraction (EF) and end-systolic volume (ESV) and end-diastolic volume (EDV) using single-photon emission tomographic equilibrium radionuclide angiocardiography (SPECT ERNA). We aimed to compare our SPECT ERNA method with cardiac MRI (CMRI) for the determination of ventricular measures.Paired measurements of LV and RV EFs and ESV and EDV were carried out by SPECT ERNA and CMRI in a group of patients who had myocardial infarction due to left anterior descending coronary artery thrombosis.SPECT ERNA and CMRI provided similar estimations of the mean (SD) LV ESV [61 (23) vs. 61 (32) ml; P=0.99] and LV EDV [134 (29) vs. 141 (44) ml; P=0.28]. The mean (SD) LV EF by SPECT ERNA was slightly but significantly smaller than that by CMRI [0.55 (0.10) vs. 0.58 (0.11) ml; P=0.03]. SPECT ERNA, compared with CMRI, produced similar mean (SD) values of RV ESV [62 (17) vs. 67 (17) ml; P=0.10] and RV EDV [153 (28) vs. 149 (29) ml; P=0.51] and somewhat larger mean (SD) RV EF [0.60 (0.06) vs. 0.55 (0.06) ml; P0.001]. Excellent correlations were found between SPECT ERNA and CMRI for combined LV ESV and EDV (R=0.85, P0.001) and combined RV ESV and EDV (R=0.85, P0.001).This study further validates SPECT ERNA as a method to measure LV and RV EF, ESV, and EDV.

Tc-99m ethyl cysteinate diethylester (ECD) and Tc-99m hexamethyl propylene amine oxime (HMPAO) are commonly used for single-photon emission computed tomography (SPECT) studies of a variety of neurologic disorders. Although these tracers have been very helpful in diagnosing and guiding treatment of neurologic disease, data describing the distribution and laterality of these tracers in normal resting brain are limited. Advances in quantitative functional imaging have demonstrated the value of using resting studies from control populations as a baseline to account for physiologic fluctuations in cerebral perfusion. Here, we report results from 30 resting Tc-99m ECD SPECT scans and 14 resting Tc-99m HMPAO scans of normal volunteers with no history of neurologic disease. Scans were analyzed with regions of interest and with statistical parametric mapping, with comparisons performed laterally (left vs. right), as well as for age, gender, and handedness. The results show regions of significant asymmetry in the normal controls affecting widespread areas in the cerebral hemispheres, but most marked in superior parietotemporal region and frontal lobes. The results have important implications for the use of normal control SPECT images in the evaluation of patients with neurologic disease.

Although subtraction ictal SPECT coregistered to MRI (SISCOM) is clinically useful in epilepsy surgery evaluation, it does not determine whether the ictal-interictal subtraction difference is statistically different from the expected random variation between 2 SPECT studies. We developed a statistical parametric mapping and MRI voxel-based method of analyzing ictal-interictal SPECT difference data (statistical ictal SPECT coregistered to MRI [STATISCOM]) and compared it with SISCOM.Two serial SPECT studies were performed in 11 healthy volunteers without epilepsy (control subjects) to measure random variation between serial studies from individuals. STATISCOM and SISCOM images from 87 consecutive patients who had ictal SPECT studies and subsequent temporal lobectomy were assessed by reviewers blinded to clinical data and outcome.Interobserver agreement between blinded reviewers was higher for STATISCOM images than for SISCOM images (kappa = 0.81 vs kappa = 0.36). STATISCOM identified a hyperperfusion focus in 84% of patients, SISCOM in 66% (p0.05). STATISCOM correctly localized the temporal lobe epilepsy (TLE) subtypes (mesial vs lateral neocortical) in 68% of patients compared with 24% by SISCOM (p = 0.02); subgroup analysis of patients without lesions (as determined by MRI) showed superiority of STATISCOM (80% vs 47%; p = 0.04). Moreover, the probability of seizure-free outcome was higher when STATISCOM correctly localized the TLE subtype than when it was indeterminate (81% vs 53%; p = 0.03).Statistical ictal SPECT coregistered to MRI (STATISCOM) was superior to subtraction ictal SPECT coregistered to MRI for seizure localization before temporal lobe epilepsy (TLE) surgery. STATISCOM localization to the correct TLE subtype was prognostically important for postsurgical seizure freedom.

Background & Aims The epidemiology of gastroparesis is unknown. We aimed to determine the incidence, prevalence, and outcome of gastroparesis in the community. Methods Using the Rochester Epidemiology Project, a medical records linkage system in Olmsted County, Minnesota, we identified county residents with potential gastroparesis. The complete medical records were reviewed by a gastroenterologist. Three diagnostic definitions were used: (1) definite gastroparesis, delayed gastric emptying by standard scintigraphy and typical symptoms for more than 3 months; (2) probable gastroparesis, typical symptoms and food retention on endoscopy or upper gastrointestinal study; (3) possible gastroparesis, typical symptoms alone or delayed gastric emptying by scintigraphy without gastrointestinal symptoms. Poisson regression was used to assess the association of incidence rates with age, sex, and calendar period. Results Among 3604 potential cases of gastroparesis, 83 met diagnostic criteria for definite gastroparesis, 127 definite plus probable gastroparesis, and 222 any of the 3 definitions of gastroparesis. The age-adjusted (to the 2000 US white population) incidence per 100,000 person-years of definite gastroparesis for the years 1996–2006 was 2.4 (95% confidence interval [CI], 1.2–3.8) for men and 9.8 (95% CI, 7.5–12.1) for women. The age-adjusted prevalence of definite gastroparesis per 100,000 persons on January 1, 2007, was 9.6 (95% CI, 1.8–17.4) for men and 37.8 (95% CI, 23.3–52.4) for women. Overall survival was significantly lower than the age- and sex-specific expected survival computed from the Minnesota white population ( P Conclusions Gastroparesis is an uncommon condition in the community but is associated with a poor outcome.

BACKGROUND To investigate the correlation between the clinical and light microscopic features of choroidal melanoma with combined PET/CT findings. METHODS This is a retrospective interventional case series of 14 patients with choroidal melanoma referred to the vitreoretinal service at the Mayo Clinic, Rochester, MN. All underwent preoperative combined PET/CT scanning and enucleation. Standardized uptake values (SUV) were correlated with the clinical and light microscopic features of the choroidal melanomas. RESULTS All 14 eyes showed uptake. The mean patient age was 62 years (SD 12.5 years). The mean tumor thickness was 9.3 mm (range 3-23 mm). Histopathology showed choroidal melanoma in all with the following cell types: 6 mixed cell type, 7 spindle cell type, and 1 epithelioid cell type. The average of the SUV means was 3.7 (range 1.7-12.8). The individual SUV means were correlated with lesion thickness (r = 0.85; P < 0.01) and largest tumor basal diameter (r = 0.65; P = 0.01). Melanomas with focal necrosis (P = 0.03) and of the mixed cell type (P < 0.01) appeared to have higher SUV means. CONCLUSIONS The majority of the choroidal melanomas had low to medium mean SUVs. Lesion size accounted for a significant portion of the variation, though nonspecific necrosis and cell type were also associated with higher SUV means.

Focused parathyroidectomy in primary hyperparathyroidism (1°HPT) is possible with accurate preoperative localization and intraoperative PTH monitoring (IOPTH). The added benefit of multimodal imaging techniques for operative success is unknown.Patients with 1°HPT, who underwent parathyroidectomy in 2012-2014 at a single institution, were retrospectively reviewed. Only the patients who underwent the standardized multimodal imaging workup consisting of (123)I/(99)Tc-sestamibi subtraction scintigraphy, SPECT, and SPECT/CT were assessed.Of 360 patients who were identified, a curative operation was performed in 96%, using pre-operative imaging and IOPTH. Imaging analysis showed that (123)I/(99)Tc-sestamibi had a sensitivity of 86% (95% CI 82-90%), positive predictive value (PPV) 93%, and accuracy 81%, based on correct lateralization. SPECT had a sensitivity of 77% (95% CI 72-82%), PPV 92% and accuracy 72%. SPECT/CT had a sensitivity of 75% (95% CI 70-80%), PPV of 94%, and accuracy 71%. There were 3 of 45 (7%) patients with negative sestamibi imaging that had an accurate SPECT and SPECT/CT. Of 312 patients (87%) with positive uptake on sestamibi (93% true positive, 7% false positive), concordant findings were present in 86% SPECT and 84% SPECT/CT. In cases where imaging modalities were discordant, but at least one method was true-positive, (123)I/(99)Tc-sestamibi was significantly better than both SPECT and SPECT/CT (p0.001). The inclusion of SPECT and SPECT/CT in 1°HPT imaging protocol increases patient cost up to 2.4-fold.(123)I/(99)Tc-sestamibi subtraction imaging is highly sensitive for preoperative localization in 1°HPT. SPECT and SPECT/CT are commonly concordant with (123)I/(99)Tc-sestamibi and rarely increase the sensitivity. Routine inclusion of multimodality imaging technique adds minimal clinical benefit but increases cost to patient in high-volume setting.

OBJECTIVE To determine if quantification of [18F]fluorodeoxyglucose (18F-FDG) uptake in a thyroid nodule found incidentally on whole-body 18F-FDG positron emission tomography-computed tomography (PET-CT) can be used to discriminate between malignant and benign aetiology. METHODS A retrospective review of all patients with focally high uptake in the thyroid as an incidental finding on 18F-FDG PET-CT from May 2003 through May 2006. The uptake in the nodules was quantified using the maximum standardized uptake value (SUVmax). The aetiology was determined by cytology and/or ultrasound, or on histopathology. RESULTS Incidental focally high uptake was found in 79/7347 patients (1.1%). In 31/48 patients with adequate follow-up, a benign aetiology was determined. Median SUVmax for the benign group was 5.6, range 2.5-53. Malignancy was confirmed in 15/48 patients. The malignancies were papillary thyroid carcinoma in 12, metastasis from squamous cell carcinoma in one, and lymphoma in two. Median SUVmax for the malignant lesions was 6.4, range 3.5-16. Cytology suspicious for follicular carcinoma was found in 2/48 patients. No statistical difference (P=0.12) was found among the SUVmax between the benign and malignant groups. CONCLUSION Focally high uptake of 18F-FDG in the thyroid as an incidental finding occurred in 1.1% of the patients. Malignancy was confirmed or was suspicious in 17/48 (35%) of the patients that had adequate follow-up. There was no significant difference in the SUVmax between benign and malignant nodules.

Purpose Primary central nervous system lymphoma (PCNSL) accounts for approximately 3% of all primary brain tumors and 1% of all non-Hodgkin lymphomas. Detection of systemic spread of PCNSL, although rare (4%), is very important since therapy is usually modified. Contrast-enhanced computed tomography (CT) is commonly used for systemic staging of PCNSL. No previous case report is available in the published literature elaborating the potential contribution of F-18 FDG PET in systemic staging of PCNSL. The purpose of this case report was to document the potential usefulness of F-18 FDG-PET in the detection of occult systemic involvement in PCNSL. Materials and methods A 50-year-old, immunocompetent, male patient completed successful treatment of PCNSL. As part of a routine pretransplant evaluation he had an F-18 FDG PET coregistered with CT (PET-CT). The PET-CT results were then compared with those of contrast-enhanced CT of the chest, abdomen, and pelvis. Results The PET-CT examination detected multiple sites of extranodal systemic disease that were not seen in the contrast-enhanced CT of the chest, abdomen, and pelvis (both studies were performed within 24 hours of each other). Percutaneous ultrasound guided biopsy confirmed the presence of systemic spread of PCNSL. The patient's subsequent therapy was modified to include rituximab with cyclophosphamide, doxorubicin, vincristine, prednisone (R-CHOP). A follow up PET-CT confirmed resolution of systemic spread. Conclusion F-18 FDG PET coregistered to CT may be a useful examination in the detection and monitoring for systemic spread of the disease in PCNSL patients.

Successful thromboendarterectomy for chronic thromboembolic pulmonary hypertension promptly improves right ventricular (RV) function by decreasing RV volume and increasing ejection fraction (EF). Single photon emission computed tomography (SPECT) equilibrium radionuclide angiocardiography (ERNA) has been validated as a measure of RV and left ventricular (LV) volume and EF.Nine patients with chronic thromboembolic pulmonary hypertension underwent electron beam computed tomography (EBCT) and SPECT ERNA cardiac studies before and after thromboendarterectomy. EBCT and SPECT ERNA measures of RV and LV volume and EF were compared. Before thromboendarterectomy, EBCT and SPECT ERNA RV and LV volumes and RV EF were similar. LV EF was within the normal range with both methods but was slightly greater (P = .004) when measured by EBCT (mean +/- SD, 0.61 +/- 0.08) compared with SPECT ERNA (0.54 +/- 0.10). Thromboendarterectomy measured by EBCT and SPECT ERNA produced marked similar and significant decreases in RV end-systolic (-72 +/- 59 mL vs -58 +/- 25 mL) and end-diastolic (-75 +/- 85 mL vs -76 +/- 32 mL) volumes and similar slight increases in RV EF (0.12 +/- 0.07 vs 0.05 +/- 0.06). Slight decreases in mean LV end-systolic (-19 +/- 23 mL vs -5 +/- 13 mL, P = .05) and end-diastolic (-32 +/- 53 mL vs -9 +/- 31 mL, P = .21) volumes occurred, with little change in mean LV EF (0.05 +/- 0.07 vs 0.00 +/- 0.10).SPECT ERNA is an accurate method for measuring RV and LV volume and EF before and after thromboendarterectomy.

This study aimed to characterize volume profiles and their differences in heart failure (HF) patients with preserved (HFpEF) and reduced (HFrEF) ventricular systolic function.The extent and distribution of volume overload and the associated implications for volume management have not been studied in decompensated HFpEF compared with HFrEF.Total blood volume (TBV) was quantitated using a standardized computer-based radiolabeled albumin dilution technique.Twenty HFpEF and 35 HFrEF patients were evaluated at hospital admission. TBV was expanded by 27 ± 21% (range -5.2% to 77%; p = 0.002) and 37 ± 25% (0% to 107%; p 0.001), respectively, above normal volumes. Red cell mass (RBCM) was expanded in HFrEF (24 ± 31%; p = 0.004) but within normal limits in HFpEF (8 ± 34%; p = 0.660) with, however, large variability in both groups. RBCM excess was more prominent in HFrEF (63% vs. 45%) than the RBCM deficit in HFpEF (35% vs.14%). With diuresis, TBV decreased to 25 ± 20% (p = 0.029) in HFrEF but was not changed in HFpEF (18 ± 20% [p = 0.173]). Body weight declined 6.6 ± 4.4 kg in HFrEF and 10.5 ± 8.3 kg (p = 0.026) in HFpEF. Interstitial fluid losses accounted for 85 ± 13% (HFrEF) and 93 ± 6% (HFpEF) (p = 0.012) of total volume removed.TBV profiles differ between HFpEF and HFrEF patients with DCHF. Quantitated volume analysis revealed both significant RBCM (polycythemia) and plasma volume excess in HFrEF, whereas a higher RBCM deficit (true anemia) was demonstrated in HFpEF. Diuresis produced only a modest reduction in intravascular volumes with persistent hypervolemia in both groups at discharge, but overall more total body fluid was lost in HFpEF. These profile differences have implications for individualizing volume management.

Improvement in esophageal cancer staging is needed. Positron emission tomography (PET), computed tomography (CT), and endoscopic ultrasound (EUS) in the staging of esophageal carcinoma were compared. PET, CT, and EUS were performed and interpreted prospectively in 75 patients with newly diagnosed esophageal cancer. Either tissue confirmation or fine needle aspiration (FNA) was used as the gold standard of disease. Sensitivity and specificity for tumor, nodal, and metastatic (TNM) disease for each test were determined. TNM categorizations from each test were used to assign patients to subgroups corresponding to the three treatment plans that patients could theoretically receive, and these were then compared. Local tumor staging (T) was done correctly by CT and PET in 42% and by EUS in 71% of patients (P value > 0.14). The sensitivity and specificity for nodal involvement (N) by modality were 84% and 67% for CT, 86% and 67% for EUS, and 82% and 60% for PET (P value > 0.38). The sensitivity and specificity for distant metastasis were 81% and 82% for CT, 73% and 86% for EUS, and 81% and 91% for PET (P value > 0.25). Treatment assignment was done correctly by CT in 65%, by EUS in 75%, and by PET in 70% of patients (P value > 0.34). EUS had superior T staging ability over PET and CT in our study group. The tests showed similar performance in nodal staging and there was a trend toward improved distant disease staging with CT or PET over EUS. Assignment to treatment groups in relation to TNM staging tended to be better by EUS. Each test contributed unique patient staging information on an individual basis.

Noninvasive imaging has been developed to measure gastric volumes. The relationship between gastric emptying and volume postprandially is unclear. The aims were to 1) develop a 3-dimensional (3D) single photon emission-computed tomography (SPECT) method to simultaneously measure gastric volume and emptying postprandially, 2) describe the course of gastric volume change during emptying of the meal, and 3) assess a 3D method measuring gastric emptying. In 30 healthy volunteers, we used 111In-planar and 99mTc-SPECT imaging to estimate gastric emptying and volume after a radiolabeled meal. A customized analysis program of SPECT imaging assessed gastric emptying. A Bland-Altman plot assessed the performance of the new SPECT analysis compared with planar analysis. Gastric volume postprandially exceeds the fasting volume plus meal volume. The course of volume change and gastric emptying differ over time. Higher differences in volumes exist relative to fasting plus residual meal volumes at 15 min (median 763 vs. 568 ml, respectively, P < 0.001), 1 h (median 632 vs. 524 ml, P < 0.001), and 2 h (median 518 vs. 428 ml, P < 0.02), in contrast to similar volumes at 3 h (median 320 vs. 314 ml, P = 0.85). Analysis of SPECT imaging accurately measures gastric emptying compared with planar imaging with median differences of 1% (IQR −2.25 to 2.0) at 1 h, 1% (−3.25 to 2.25) at 2 h, and −2.5% (−4 to 0) at 3 h. Gastric volume exceeds meal volume during the first 2 postprandial hours, and simultaneous measurements of gastric volume and emptying can be achieved with a novel 3D SPECT method.

Nuclear medicine sestamibi parathyroid imaging is now a standard preoperative assessment for patients with hyperparathyroidism. Since the introduction of Technetium-99m (99mTc) sestamibi for parathyroid imaging in 1989 there has been a steady refinement in the imaging technique. The accuracy is determined by the scan technique employed, with the dual-isotope (123Iodine/99mTc sestamibi)scan providing better accuracy than the simpler sestamibi washout method. Now the pathologic parathyroid process can be localized preoperatively with great confidence, limiting the time and extent of the neck dissection and allowing a significant number of parathyroid surgeries to be performed as outpatient procedures.

Summary: Purpose: To determine the extent to which periictal subtraction single-photon emission computed tomography (SPECT) may improve detection and definition of the epileptogenic zone in patients with focal malformations of cortical development (MCDs). Methods: Subtraction SPECT coregistered to magnetic resonance (MR) images (SISCOM) were constructed for 22 consecutive patients with focal MCDs who underwent periictal SPECT injection (18 ictal and four postictal). In the 17 patients who had epilepsy surgery, concordance between the site of SISCOM localization and site of surgical resection was determined by coregistration of SISCOM images with postoperative MRIs. Results: SISCOM images were localizing in 19 (86%) patients, including eight of the 10 with nonlocalizing MRI. Concordance of SISCOM localization was 91% with MRI localization, 93% with scalp ictal EEG localization, and 100% with intracranial EEG localization. Eight patients whose SISCOM localization was concordant with the surgical resection site had lower postoperative seizure frequency scores (SFSs; p = 0.04) and greater postoperative improvement in SFSs (p = 0.05) than the nine patients whose SISCOM was either nonconcordant or nonlocalizing. On multiple regression analysis, a model combining SISCOM concordance with surgical resection site and extent of MRI lesion resection was predictive of postoperative SFS (R2= 0.47; p = 0.03). Conclusions: Periictal subtraction SPECT using the SISCOM technique provides useful information for seizure localization in patients with focal MCDs, even when MRI is nonlocalizing.

Objective: To evaluate positron emission tomography as an imaging tool in the diagnosis, evaluation, and management of autoimmune inner ear disease. Background: Autoimmune inner ear disease is a form of cochleovestibular disease associated with variable hearing loss and vertigo for which no reliable diagnostic tests are available. Methods: Pilot study of 10 patients with autoimmune inner ear disease and 5 sex-matched and age-matched control subjects without any history of autoimmune inner ear disease, who underwent limited positron emission tomography of the inner ear. Five patients with new or active autoimmune inner ear disease underwent serial positron emission tomography before and after 4 to 6 weeks of a high-dose tapering course of prednisone. The subjects had cranial magnetic resonance imagining, audiometric and vestibular studies, and heat-shock protein (HSP-70) measurements. Reading of the positron emission tomography scans was blinded. Results: Positron emission tomography was normal in 4 of 5 normal control subjects and abnormal in I with normal audiometric and vestibular studies and positive HSP-70. Of patients with established and stable autoimmune inner ear disease, 4 of 5 had no positron emission tomography abnormalities and negative HSP-70, and the one with abnormal positron emission tomography shortly thereafter manifested clinically active disease. Of the 5 patients with active autoimmune inner ear disease monitored serially, 4 had an initial abnormal positron emission tomography in at least one ear, which became normal in all but 1 patient after therapy. HSP-70 correlated with disease activity. Only I patient with clinically active autoimmune inner ear disease had a normal positron emission tomography before and after therapy (the HSP-70 was positive before therapy and negative after the therapy). Conclusions: Positron emission tomography, especially when combined with HSP-70 determination, may be a useful technique for assessing disease in patients with autoimmune inner ear disease.

SUMMARY This study was performed in order to assess [(18)F]fluorodeoxyglucose white blood cell ((18)F-FDG WBC) dosimetry in normal human subjects. Using previously reported methods, mixed cell suspensions of autologous leukocytes were prepared from four normal volunteers. Leukocytes were labelled in heparin-saline by incubation with (18)F-FDG at 37 degrees C for 20 min. After washing and resuspension, (18)F-FDG WBCs (225-315 MBq) were administered by intravenous injection. Whole-body imaging was performed at 0.5, 1, 2, 4 and 6 h using a GE Varicam with 511 keV collimation. Blood samples were obtained at corresponding times as well as fractionated urinary collection. Whole-body anterior and posterior images were used for calculation of organ dosimetry. Uptake of (18)F-FDG WBCs occurred predominantly within the reticulo-endothelial system. Plasma activity, urinary excretion (9.9+/-2.3% at 6 h), and brain uptake (1.7+/-0.4%) were consistent with partial elution of (18)F-FDG. Positron emission tomography imaging performed at 5-6 h after injection yielded good quality images of reticulo-endothelial uptake. Whole-body and organ dosimetry for (18)F-FDG WBCs in doses of 225-250 MBq are comparable with reported results for conventional doses of (111)In oxine labelled leukocytes. Further studies of (18)F-FDG WBC as an agent for positron emission tomography imaging of inflammatory disease appear warranted.

The long-term protective effect of stronger back muscles on the spine was determined in 50 healthy white postmenopausal women, aged 58-75 years, 8 years after they had completed a 2 year randomized, controlled trial. Twenty-seven subjects had performed progressive, resistive back-strengthening exercises for 2 years and 23 had served as controls. Bone mineral density, spine radiographs, back extensor strength, biochemical marker values, and level of physical activity were obtained for all subjects at baseline, 2 years, and 10 years. Mean back extensor strength (BES) in the back-exercise (BE) group was 39.4 kg at baseline, 66.8 kg at 2 years (after 2 years of prescribed exercises), and 32.9 kg at 10 years (8 years after cessation of the prescribed exercises). Mean BES in the control (C) group was 36.9 kg at baseline, 49.0 kg at 2 years, and 26.9 kg at 10 years. The difference between the two groups was still statistically significant at 10 year follow-up (p = 0.001). The difference in bone mineral density, which was not significant between the two groups at baseline and 2 year follow-up, was significant at 10 year follow-up (p = 0.0004). The incidence of vertebral compression fracture was 14 fractures in 322 vertebral bodies examined (4.3%) in the C group and 6 fractures in 378 vertebral bodies examined (1.6%) in the BE group (chi-square test, p = 0.0290). The relative risk for compression fracture was 2.7 times greater in the C group than in the BE group. To our knowledge, this is the first study reported in the literature demonstrating the long-term effect of strong back muscles on the reduction of vertebral fractures in estrogen-deficient women.

PURPOSE: Samarium-153 ethylene diamine tetramethylene phosphonate (153Sm-EDTMP), a bone-seeking radiopharmaceutical, provides therapeutic irradiation to osteoblastic bone metastases. Because the dose-limiting toxicity of 153Sm-EDTMP is thrombocytopenia, a dose-escalation trial using peripheral-blood progenitor cells (PBPCs) or marrow support was conducted to treat metastatic bone cancer. PATIENTS AND METHODS: Patients with locally recurrent or metastatic osteosarcoma or skeletal metastases avid on bone scan were treated with 1, 3, 4.5, 6, 12, 19, or 30 mCi/kg of 153Sm-EDTMP. RESULTS: Thirty patients were treated with 153Sm-EDTMP. Transient symptoms of hypocalcemia were seen at 30 mCi/kg. Estimates of radioisotope bound to bone surfaces and marrow radiation dose were linear with injected amount of 153Sm-EDTMP. Cytopenias also occurred in all subjects and were dose-related. At day +13 after 153Sm-EDTMP, residual whole-body radioactivity was 1% to 65% of whole-body radioactivity considered safe for PBPC infusion, 3.6 mCi. After PBPC or marrow infusion on day +14 after 153Sm-EDTMP, recovery of hematopoiesis was problematic in two patients at the 30 mCi/kg dose infused with less than 2 × 106 CD34+/kg on day +14, but not in other patients. Reduction or elimination of opiates for pain was seen in all patients. Patients had no adverse changes in appetite or performance status. CONCLUSION: 153Sm-EDTMP with PBPC support can provide bone-specific therapeutic irradiation (estimates of 39 to 241 Gy). Hematologic toxicity at 30 mCi 153Sm-EDTMP/kg requires PBPC grafts with more than 2 × 106 CD34+/kg to overcome myeloablative effects of skeletal irradiation. Nonhematologic side effects are minimal.

Objective: To evaluate the benefit of statistical SPECT processing over traditional subtraction methods, we compared ictal–interictal SPECT analyzed by statistical parametric mapping (SPM) (ISAS), statistical ictal SPECT coregistered to MRI (STATISCOM), and subtraction ictal–interictal SPECT coregistered with MRI (SISCOM) in patients with MRI-negative focal temporal lobe epilepsy (nTLE) and extratemporal lobe epilepsy (nETLE). Methods: We retrospectively identified 49 consecutive cases of drug-resistant focal epilepsy that had a negative preoperative MRI and underwent interictal and ictal SPECT prior to resective epilepsy surgery. Interictal and ictal SPECT scans were analyzed using SISCOM, ISAS, and STATISCOM to create hyperperfusion and hypoperfusion maps for each patient. Reviewers blinded to clinical data and the SPECT analysis method marked the site of probable seizure origin and indicated their confidence in the localization. Results: In nTLE and nETLE, the hyperperfusions detected by STATISCOM (71% nTLE, 57% nETLE) and ISAS (67% nTLE, 53% nETLE) were more often colocalized with surgery resection site compared to SISCOM (38% nTLE, 36% nETLE). In nTLE, localization of the hyperperfusion to the region of surgery was associated with an excellent outcome for STATISCOM ( p = 0.005) and ISAS ( p = 0.027), but not in SISCOM ( p = 0.071). This association was not present in nETLE for any method. Conclusion: In an unselected group of patients with normal MRI and focal epilepsy, SPM-based methods of SPECT processing showed better localization of SPECT hyperperfusion to surgical resection site and higher interobserver agreement compared to SISCOM. These results show the benefit of statistical SPECT processing methods and further highlight the challenge of nETLE.

To determine whether localization of extratemporal epilepsy with subtraction ictal SPECT coregistered with MRI (SISCOM) is predictive of outcome after resective epilepsy surgery, whether SISCOM images provide prognostically important information compared with standard tests, and whether blood flow change on SISCOM images is useful in determining site and extent of excision required.The value of SISCOM in predicting surgical outcome for extratemporal epilepsy is unknown, especially if MRI findings are nonlocalizing.SISCOM images in 36 consecutive patients were classified by blinded reviewers as "localizing and concordant with site of surgery," "localizing but nonconcordant with site of surgery," or "nonlocalizing." SISCOM images were coregistered with postoperative MRI, and reviewers visually determined whether cerebral cortex underlying the SISCOM focus had been completely resected, partially resected, or not resected.Twenty-four patients (66.7%) had localizing SISCOM, including 13 (76.5%) of those without a focal MRI lesion. Eleven of 19 patients (57.9%) with localizing SISCOM concordant with the surgical site, compared with 3 of 17 (17.6%) with nonlocalizing or nonconcordant SISCOM, had an excellent outcome (p0.05). With logistic regression analysis, SISCOM findings were predictive of postsurgical outcome, independently of MRI or scalp ictal EEG findings (p0.05). The extent of resection of the cortical region of the SISCOM focus was significantly associated with the rate of excellent outcome (100% with complete resection, 60% with partial resection, and 20% with nonresection, p0.05).SISCOM images may be useful in guiding the location and extent of resection in extratemporal epilepsy surgery.

Radiolabelled leukocytes are useful for the imaging of inflammation and infection, and 18F-fluorodeoxyglucose (18F-FDG) is known to concentrate in metabolically active cells. We evaluated the feasibility of leukocyte labelling with 18F-FDG using ACD and heparin anticoagulants at 20 degrees C and 37 degrees C, with and without gentle mixing during incubation. With leukocytes (WBC) harvested from 20 ml blood, studies were performed using 18F-FDG in concentrations of 3.7-74 MBq (0.1-2.0 mCi). 18F-FDG WBC stability in platelet-poor plasma was assessed at 1-4 h. Satisfactory labelling efficiency was achieved with incubation in heparin-saline at 37 degrees C for 30 min (62.7+/-1.6%), and was further enhanced by mixing during incubation (78.1+/-3.9%). Cell labelling was predominantly of granulocytes (78.5+/-1.4%). 18F-FDG WBC was relatively stable in platelet-poor plasma for up to 4 h, and no cell staining was observed in viability studies using trypan blue. These results indicate the feasibility of leukocyte labelling with 18F-FDG, providing an approach that may be useful in PET imaging of inflammation and infection.

Postprandial symptoms of bloating, distension, early satiety, and nausea are associated with impaired postprandial gastric accommodation, which is detectable by means of an intragastric, barostatically controlled balloon in the proximal stomach and by ultrasound in the distal stomach. Our aim was to develop a noninvasive method to measure the entire gastric accommodation reflex. In 10 healthy volunteers, we used single photon emission computed tomography (SPECT) to measure fasting and postprandial gastric volumes. This method involved intravenous injection of99mTc pertechnetate and gastric reconstruction of tomographic images with Analyze software. SPECT-Analyze imaging detects the postprandial gastric accommodation reflex in vivo. Mean fasting gastric volume was 182 ± 11 (SE) ml and mean postprandial volume was 690 ± 32 ml ( P < 0.001). Both proximal and distal segments of stomach showed a two- to almost fourfold difference in volumes postprandially. Intraobserver coefficients of variation in estimated fasting and postprandial volumes were 9 and 8%; interobserver variations were 13 and 12%, respectively. SPECT-Analyze noninvasively measures postprandial gastric (total, proximal, and distal) accommodation in humans. This method appears promising to compare the accommodation response in health and disease and to perform mechanistic studies of the accommodation response.

OBJECTIVES—Most studies that clinically validated peri-ictal SPECT in intractable partial epilepsy had used technetium-99m-hexamethylpropylene amine oxime (99mTc-HMPAO or 99mTc-exametazime) as the radiopharmaceutical. Because of some theoretical advantages, technetium-99m-ethyl cysteinate diethylester (99mTc-ECD or 99mTc-bicisate) is increasingly being used instead. This study compares unstabilised 99mTc-HMPAO and 99mTc-ECD in the performance of peri-ictal SPECT in partial epilepsy. METHODS—The injection timing and localisation rates in 49 consecutive patients with partial epilepsy who had peri-ictal injections with unstabilised 99mTc-HMPAO were compared with 49 consecutive patients who had peri-ictal injections with 99mTc-ECD. Quantitative cortical/subcortical and cortical/extracerebral uptake ratios were also compared. Subtraction SPECT coregistered to MRI (SISCOM) was performed in patients whose interictal SPECTS were available. RESULTS—In the 99mTc-ECD patients, the latency from seizure commencement to injection was shorter (median 34 v 80 seconds, p0.05). Blinded review of the SISCOM images were localising in a higher proportion of the 99mTc-ECD patients (40/45 (88.9%) v 25/37 (67.6%), p

To determine the frequency and patterns of periictal cerebellar hyperperfusion, whether it is associated with increased cerebellar atrophy, and whether cerebellar hyperperfusion and cerebellar atrophy are associated with predisposing clinical factors or with the outcome of epilepsy surgery.Periictal and interictal SPECT scans and volumetric brain magnetic resonance imaging (MRI) were quantitatively analyzed in 54 consecutive patients with medically refractory partial epilepsy. Their histories were reviewed and their postsurgical outcomes assessed.Significant periictal cerebellar hyperperfusion was found in 26 (48.1%) patients, of whom 18 had CCH, two had homolateral cerebellar hyperperfusion (HCH), and six had symmetrical bilateral hyperperfusion (BCH). No relation found between the site of the SPECT seizure localization and the presence or type of cerebellar hyperperfusion. CCH was more common when the injected seizure involved unilateral clonic motor activity (p0.05). A smaller MRI relative cerebellar volume (cerebellar volume/cerebral volume) was correlated with a greater seizure frequency (Rs = -0.30; p0.05) but not with the duration of epilepsy. There was no difference in the cerebellar volumes between the different patterns of cerebellar perfusion (p0.05). However, patients without a focal structural MRI lesion had significantly smaller cerebellar volumes (p0.05). In patients who underwent epilepsy surgery (n = 31), there was a trend for those without excellent outcomes to have smaller relative cerebellar volumes than did those with excellent outcome (10.6 vs. 11.8%; p = 0.08).Periictal changes in cerebellar perfusion, particularly CCH, are common in patients with intractable partial epilepsy. However, periictal hyperperfusion does not appear to be a major contributor to the development of cerebellar atrophy.

The scintigraphic measurement of colonic transit is currently performed using 111In ion exchange resin pellets delivered to the colon in a capsule coated with a pH sensitive polymer, methacrylate, which dissolves in the distal ileum. However, in the USA, this requires an investigational drug permit. Our aim was to evaluate the in vitro binding characteristics of activated charcoal in milieus that mimicked gastric and small intestinal content. The in vitro incubation of activated charcoal was performed with Na99Tc(m)O4, 99Tc(m)-DTPA, 111InCl3, 111In-DTPA, 201TlCl and 67Ga-citrate in the pH range 2-4 and pH 7.2 at 37 degrees C. We estimated the association of radiopharmaceuticals with the activated charcoal over a 3 h in vitro incubation. With the exception of 67Ga-citrate, the association of activated charcoal with the other radiopharmaceuticals was approximately 100% throughout the 3 h incubation. In conclusion, activated charcoal appears to adsorb avidly with common radioisotopes, and appears promising as an alternative to resin ion exchange pellets used for the measurement of gastrointestinal transit by scintigraphy.

Computer-aided subtraction of the co-registered and normalized interictal from the ictal single photon emission tomography (SPET) scan, followed by co-registration to the magnetic resonance image, may improve the utility of ictal SPET in the localization of partial epilepsy. This paper describes and technically validates our method. The SPET to SPET co-registration was tested using six sequential 99Tc(m) brain phantom SPET images of different known positions (15 matches). The registration error was determined by multiplying the calculated match transformation matrix by the inverse of the known transformation matrix. The 'worst case' co-registration error was less that one voxel diameter in all cases (median 3.2 mm, range 1.2-4.8 mm). For interictal to ictal SPET registrations in 10 consecutive intractable partial epilepsy patients, a similar root mean square distance (RMSD) between corresponding points on the matched scans was found as for the phantom studies (median 2.2 vs 2.6 mm). The appropriateness of our normalization was studied by comparing the pixel intensity distributions between the matched scans, and by analysing the subtraction pixel intensity distribution. The pixel intensity distribution for both the normalized phantom, and paired normalized patient studies, were closely matched to each other except for the extreme values, which in clinical situations likely represent regions of ictal activation or depression. The subtraction image intensity distributions were symmetrically centred on zero for all values up to at least within the 5th to 95th centile range, confirming good normalization for the 'non-activated' pixels. Also, a linear relationship was demonstrated between the measured pixel intensity on the phantom scans and the true changes in 99Tc(m) activity based on its decay constant. The results of this study demonstrate that our method produces accurate SPET to SPET co-registration, and appropriate SPET normalization, thereby allowing a valid ictal subtraction image to be derived.

This study sought to quantitate total blood volume (TBV) in patients hospitalized for decompensated chronic heart failure (DCHF) and to determine the extent of volume overload, and the magnitude and distribution of blood volume and body water changes following diuretic therapy.The accurate assessment and management of volume overload in patients with DCHF remains problematic.TBV was measured by a radiolabeled-albumin dilution technique with intravascular volume, pre-to-post-diuretic therapy, evaluated at hospital admission and at discharge. Change in body weight in relation to quantitated TBV was used to determine interstitial volume contribution to total fluid loss.Twenty-six patients were prospectively evaluated. Two patients had normal TBV at admission. Twenty-four patients were hypervolemic with TBV (7.4 ± 1.6 liters) increased by +39 ± 22% (range, +9.5% to +107%) above the expected normal volume. With diuresis, TBV decreased marginally (+30 ± 16%). Body weight declined by 6.9 ± 5.2 kg, and fluid intake/fluid output was a net negative 8.4 ± 5.2 liters. Interstitial compartment fluid loss was calculated at 6.2 ± 4.0 liters, accounting for 85 ± 15% of the total fluid reduction.TBV analysis demonstrated a wide range in the extent of intravascular overload. Dismissal measurements revealed marginally reduced intravascular volume post-diuretic therapy despite large reductions in body weight. Mobilization of interstitial fluid to the intravascular compartment with diuresis accounted for this disparity. Intravascular volume, however, remained increased at dismissal. The extent, composition, and distribution of volume overload are highly variable in DCHF, and this variability needs to be taken into account in the approach to individualized therapy. TBV quantitation, particularly serial measurements, can facilitate informed volume management with respect to a goal of treating to euvolemia.

Summary: Purpose: Ictal single-photon emission computed tomography (SPECT) may be a reliable indicator of the ictal onset zone in patients with intractable partial epilepsy who are being considered for epilepsy surgery. The rationale for the illustrated case report is to evaluate the use of an innovation in SPECT imaging in a patient with nonlesional extratemporal epilepsy. Methods: We investigated the presurgical evaluation and operative outcome in a patient with intractable partial epilepsy. The ictal semiology indicated a “hypermotor” seizure with bipedal automatism. The electroclinical correlation and magnetic resonance imaging (MRI) did not suggest the appropriate localization of the epileptogenic zone. A subtraction periictal SPECT coregistered to MRI (SISCOM) was peformed. Results: SISCOM revealed a region of localized hyperperfusion in the right supplementary sensorimotor area. Chronic intracranial EEG monitoring confirmed the relationship between the localized SISCOM alteration and the ictal onset zone. The patient was rendered seizure free after surgical treatment. Conclusions: SISCOM may be used to identify potential candidates for surgical treatment of nonlesional extratemporal epilepsy. Periictal imaging may also alter the strategy for intracranial EEG recordings and focal cortical resection.

Differentiation of idiopathic Parkinson's disease (PD) from multiple system atrophy (MSA) can be difficult. Methods devised to help distinguish the two disorders include standardized autonomic testing and cardiac imaging with iodine-123 meta-iodobenzylguanidine myocardial scintigraphy. MSA patients had more severe adrenergic and overall autonomic dysfunction when compared to control and PD patients. Area of anhidrosis on thermoregulatory sweat testing was greater in MSA (67.4±12.42, p

Objective To explore the prognostic value of F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) in radioiodine-negative patients with differentiated follicular cell-derived thyroid carcinoma with circulating antithyroglobulin autoantibodies (TgAb). Methods We retrospectively reviewed cases of all patients with differentiated thyroid cancer and increased TgAb referred for FDG-PET at Mayo Clinic, Rochester, Minnesota, from August 2001 to December 2004. PET findings were compared with results of other imaging and laboratory studies. Follow-up information was recorded until 19 December 2009. Results Of the 17 patients identified, PET results were true positive in 10 and false negative in two. In eight of these 12 patients with confirmed residual or recurrent disease, the increased TgAb level persisted and the disease progressed. In four of the 12 patients, TgAb decreased or disappeared after further treatment. In five patients, no residual or recurrent disease was found during follow-up. PET results were true negative in these five patients; TgAb disappeared spontaneously in four of these patients. Conclusions Negative PET results were associated with the absence of active disease and disappearing TgAb over time. FDG-avid residual lesions were associated with more aggressive disease and persistently increased TgAb.

Background Psychogenic movement disorders pose formidable challenges to diagnosis and treatment reflecting our limited understanding of the basic brain mechanisms that cause them. Recently, functional brain imaging has been utilized to study psychogenic movement disorders. Objectives To identify characteristic patterns of cerebral perfusion distinguishing psychogenic tremor (PT) from essential tremor (ET). Methods We studied five patients each with PT, ET and normal controls. SPECT imaging was performed at rest and during a tremor-inducing motor task. Results In ET, rest imaging revealed increased rCBF (relative cerebral blood flow) in cerebellar hemispheres and left inferior frontal gyrus. During the motor task, ET patients demonstrated increased rCBF in the supplementary motor area (SMA) and contralateral motor cortex and reduced rCBF in the cerebellum and visual cortex. In contrast, PT images at rest revealed increased rCBF in left inferior frontal gyrus and left insula. Motor task imaging revealed increased rCBF in the cerebellum and reduced rCBF in anterior regions of the default mode network. Conclusions Our study revealed distinct patterns of cerebral perfusion during rest and motor task that distinguish PT from ET. Deactivation of the default mode network may serve as a marker for psychogenic movement disorders.

The purpose of this study was to compare the diagnostic accuracy of glucose metabolism and amyloid deposition as demonstrated by (18)F-FDG and Pittsburg Compound B (PiB) PET to evaluate subjects with cognitive impairment.Subjects were selected from existing participants in the Mayo Alzheimer's Disease Research Center or Alzheimer's Disease Patient Registry programs. A total of 20 healthy controls and 17 amnestic mild cognitive impairment (aMCI), 6 nonamnestic mild cognitive impairment (naMCI), and 13 Alzheimer disease (AD) subjects were imaged with both PiB and (18)F-FDG PET between March 2006 and August 2007. Global measures for PiB and (18)F-FDG PET uptake, normalized to cerebellum for PiB and pons for (18)F-FDG, were compared. Partial-volume correction, standardized uptake value (SUV), and cortical ratio methods of image analysis were also evaluated in an attempt to optimize the analysis for each test.Significant discrimination (P0.05) between controls and AD, naMCI and aMCI, naMCI and AD, and aMCI and AD by PiB PET measurements was observed. The paired groupwise comparisons of the global measures demonstrated that PiB PET versus (18)F-FDG PET showed similar significant group separation, with only PiB showing significant separation of naMCI and aMCI subjects.PiB PET and (18)F-FDG PET have similar diagnostic accuracy in early cognitive impairment. However, significantly better group discrimination in naMCI and aMCI subjects by PiB, compared with (18)F-FDG, was seen and may suggest early amyloid deposition before cerebral metabolic disruption in this group.

To explore the prognostic value of 2-deoxy-2-[18F]fluoro-d-glucose (FDG) positron emission tomography (PET) in patients with suspected residual or recurrent medullary thyroid carcinoma (MTC). This retrospective study included all patients with MTC examined with FDG-PET at Mayo Clinic, Rochester, Minnesota, from October 1999 to March 2008. The PET results were compared with other imaging studies and clinical findings, including carcinoembryonic antigen and calcitonin levels. Twenty-nine patients with MTC were included. PET was positive in 14 patients, with follow-up information for 11; six died from metastatic disease, four had disease progression, and one remained in stable condition. PET was negative in 15 patients, with follow-up for 12; one had recurrent disease, and 11 had no evidence of clinical disease. Calcitonin doubling time was shorter for PET-positive than for PET-negative patients. FDG-PET has high prognostic value in patients with suspected residual or recurrent MTC.

Objective To explore the value of 18 F fluorodeoxy-glucose (FDG) positron emission tomography (PET) in Burkitt's lymphoma. Methods All Burkitt's lymphoma patients referred for FDG PET or FDG PET/computed tomography (CT) exams at our institution from June 2003 to June 2006 were included. Selected patients were followed and clinical information was reviewed retrospectively. Results from FDG PET–PET/CT, as blindly reviewed by a consensus of two experienced readers, were compared with the status of the disease as determined by other laboratory, clinical and imaging exams and clinical follow-up. FDG PET–PET/CT results were classified as true positive or negative and false positive or negative. The degree of FDG uptake in the positive lesions was semiquantified as maximum standard uptake value (SUVmax). Results Fifty-seven FDG PET–PET/CT exams were done in 15 patients. Seven exams were done for initial staging, 8 during and 14 after the completion of therapy, and 28 for disease surveillance. For nodal disease FDG PET–PET/CT was true positive in 8, true negative in 47 and false positive in 2 exams (sensitivity 100%, specificity 96%). For extranodal disease FDG PET–PET/CT was true positive in 6, true negative in 48 and false positive in 3 exams (sensitivity 100%, specificity 94%). The mean SUVmax for the positive nodal lesions was 15.7 (range 6.9–21.7, median 18.5) and for extranodal lesions was 14.2 (range 6.2–24.3, median 12.4). Conclusions FDG PET–PET/CT is sensitive for the detection of viable disease in Burkitt's lymphoma. Affected areas demonstrated high degree of uptake that was reversible upon successful implementation of treatment.

OBJECTIVE. The objective of our study was to show the efficacy and safety of percutaneous ethanol ablation in managing recurrent primary hyperparathyroidism in patients with multiple endocrine neoplasia type 1 (MEN1) after subtotal parathyroidectomy.CONCLUSION. Ethanol ablation is a viable alternative to reoperation for the management of recurrent primary hyperparathyroidism in patients with MEN1.

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive solid tumors in humans. The use of positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) in ATC has not been studied, and only a few case reports have been published. The objective of this study was to investigate the potential contribution of 18F-FDG PET to the clinical management of patients with ATC.All patients with ATC studied with 18F-FDG PET from August 2001 through March 2007 were included. The PET results were correlated with computed tomography, ultrasound, magnetic resonance imaging, bone scan, histology, and clinical follow-up. The FDG uptake was semiquantified as maximum standard uptake value. Any change in the treatment plan as a direct result of the PET findings as documented in the clinical notes was recorded.Sixteen patients were included. True-positive PET findings were seen for all primary tumors, in all nine patients with lymph node metastases, in five out of eight patients with lung metastases, and in two patients with distant metastases other than lung metastases. In 8 of the 16 patients, the medical records reported a direct impact of the PET findings on the clinical management.ATC demonstrates intense uptake on 18F-FDG PET images. In 8 of the 16 patients (50%), the medical records reported a direct impact of the PET findings on the management of the patient. PET may improve disease detection and have an impact on the management of patients with ATC relative to other imaging modalities.

Patients with papillary thyroid carcinoma (PTC) may suffer recurrence despite thyroidectomy and complete radioiodine (RAI) ablation. Reoperation is vitally dependent on accurate and complete disease localization, typically utilizing cervical ultrasonography (US) and/or computed tomography. Our aim was to determine the comparative value of F18-fluorodeoxyglucose positron emission tomography (PET) to US for localization of locoregional recurrence in patients who underwent reoperation for recurrent PTC. From 1999 to 2004, 30 patients who underwent re-exploration and 100 nonoperated patients who were investigated with PET for possible recurrent PTC were reviewed. The surgical group [9 males, 21 females; mean age = 50 years (range = 18–84 years)] all had received RAI ablation. Preoperative thyroid-stimulating hormone (TSH), thyroglobulin (Tg), and location of metastasis were recorded for each imaging study and surgical exploration. All separate sites that contained disease pathologically must have been identified by imaging for a patient to be considered true positive (TP). PET scans were TP in 43%, false positive in 7%, false negative (FN) in 50%, and had a sensitivity of 46%. Comparable US results were 86%, 10%, 3%, and 96%. Of the 15 patients with FN PET scans, 13 had lymph node metastasis less than 2 cm in diameter, 11 had Tg ≤ 10 μg/L, and the TSH < 20 in 13. In only 3 of the 30 (10%) patients was PET deemed to add value. At least with suppressed TSH, PET scanning in reoperative PTC patients appears to offer modest benefit beyond high-resolution US.

Objective To determine the value of 18F-FDG PET/CT in the different manifestations of primary central nervous system lymphoma (PCNSL) in HIV-negative patients. Methods All PCNSL and HIV-negative patients referred for PET/CT in our institution from July 2001 to June 2006 were retrospectively studied. PET/CT examinations were reviewed by two experienced readers and evaluated for each possible anatomical site of nervous system involvement: cerebral, spinal/nerve and ocular. PET/CT results were characterized as true positive or negative and false positive or negative according to the status of the disease, which was determined after the evaluation of biopsies, laboratory, clinical and imaging examinations, and follow-up. Results Forty-two PET/CT examinations were carried out in 25 PCNSL patients. For intracerebral disease, PET/CT was true positive in 13 cases, true negative in 27 and false negative in two. For disease involving spinal cord and/or nerves, PET/CT was true positive in four cases, true negative in 37 and false negative in one. For ocular disease, PET was true positive in only one case and false negative in four. The sensitivity of PET/CT in detecting active disease in the brain was 87% (13/15), in the spine/nerves 80% (4/5), and in the eyes only 20% (1/5). Conclusion PET/CT seems to be sensitive for the detection of viable intracerebral as well as for spinal and peripheral nerve disease, but not for the detection of ocular involvement.

Our purpose was to determine the clinical significance of diffusely increased 18F-FDG uptake in the thyroid gland as an incidental finding on PET/CT. Methods: All patients who were found to have diffuse thyroid uptake on 18F-FDG PET/CT in our institution between November 2004 and June 2006 were investigated and compared with an age- and sex-matched control group. The 18F-FDG uptake in the thyroid was semiquantified using maximum standardized uptake value and correlated to the available serum thyroid-stimulating hormone (TSH) and thyroid peroxidase (TPO) antibody levels using regression analysis. Results: Of the 4,732 patients, 138 (2.9%) had diffuse thyroid uptake. Clinical information was available for 133 of the 138 patients. Sixty-three (47.4%) had a prior diagnosis of hypothyroidism or autoimmune thyroiditis, of whom 56 were receiving thyroxine therapy. In the control group, consisting of 133 patients with no thyroid uptake, there were 13 (9.8%) with a prior diagnosis of hypothyroidism, 11 of whom were receiving thyroxine therapy. In the study group, 38 (28.6%) of 133 patients did not undergo any further investigation for thyroid disease, whereas 32 (24.1%) of 133 patients were examined for thyroid disease after PET. Nineteen were found with autoimmune thyroiditis or hypothyroidism, and replacement therapy was initiated in 12. No significant correlation was found between maximum standardized uptake value and TSH (P = 0.09) or TPO antibody (P = 0.68) levels. Conclusion: The incidental finding of increased 18F-FDG uptake in the thyroid gland is associated with chronic lymphocytic (Hashimoto9s) thyroiditis and does not seem to be affected by thyroid hormone therapy. SUV correlated neither with the degree of hypothyroidism nor with the titer of TPO antibodies.

Background: Choroidal metastases are the most common intraocular malignancy and are the first sign of systemic malignancy in approximately one-third of patients. Of patients with no previous diagnosis of cancer, oncological evaluation fails to find the primary lesion in approximately 50% of cases. Newer imaging modalities such as combined positron emission tomography/computed tomography (PET/CT) may improve the yield of the systemic work-up. Methods: Consecutive patients presenting with presumed choroidal metastases were evaluated with whole body combined PET/CT scanning. Results: Four patients presenting to a tertiary referral hospital with choroidal metastases as the first sign of systemic malignancy were evaluated. In all four cases, PET/CT demonstrated the ocular lesion, and the primary malignancy which was confirmed by tissue biopsy. False-negative results were seen in two cases of cerebral metastases. PET/CT demonstrated lesions not visible on CT or magnetic resonance imaging in two cases. Conclusions: Combined PET/CT is a useful addition to the work-up of patients with choroidal metastases. It provides the opportunity to detect lesions not visible with other imaging modalities and the ability to image patients with contraindications to magnetic resonance imaging. It is essential to correlate PET images with clinical information and the results of other imaging modalities and tissue biopsy remains the gold standard in the diagnosis of malignancy. False positives and negatives can occur with PET/CT, and further research is needed before this promising technology becomes a routine part of the evaluation of patients with choroidal metastases.

The purpose of this study was to directly compare nodule-enhancement CT and 18F-FDG PET in the characterization of indeterminate solitary pulmonary nodules (SPNs) greater than 7 mm in size.Examinations from patients undergoing both nodule-enhancement CT and 18F-FDG PET to characterize the same indeterminate SPN were reviewed. For nodule-enhancement CT, an SPN was considered malignant when it showed an unenhanced to peak contrast-enhanced increase in attenuation greater than 15 H. Fluorine-18-FDG PET studies were blindly reinterpreted by two qualified nuclear radiologists. SPNs qualitatively showing hypermetabolic activity greater than the mediastinal blood pool were interpreted as malignant. These interpretations were compared with the original prospective clinical readings and to semiquantitative standardized uptake value (SUV) analysis. Results were compared with pathologic and clinical follow-up.Forty-two pulmonary nodules were examined. Twenty-five (60%) were malignant, and 17 (40%) were benign. Nodule-enhancement CT was positive in all 25 malignant nodules and in 12 benign nodules, with sensitivity and specificity of 100% and 29%, respectively, and with a positive predictive value (PPV) and negative predictive value (NPV) of 68% and 100%, respectively. Qualitative 18F-FDG PET interpretations were positive in 24 of the 25 malignant nodules and in four benign nodules. Fluorine-18-FDG PET was considered negative in one malignant nodule and in 13 of the 17 benign nodules. This correlates with a sensitivity and specificity of 96% and 76%, respectively, and with a PPV and NPV of 86% and 93%, respectively. Original prospective 18F-FDG PET and semiquantitative SUV analysis showed sensitivity, specificity, PPV, and NPV of 88%, 76%, 85%, and 81% and 84%, 82%, 88%, and 78%, respectively.Due to its much higher specificity and only slightly reduced sensitivity, 18F-FDG PET is preferable to nodule-enhancement CT in evaluating indeterminate pulmonary nodules. However, nodule-enhancement CT remains useful due to its high NPV, convenience, and lower cost. Qualitative 18F-FDG PET interpretation provided the best balance of sensitivity and specificity when compared with original prospective interpretation or SUV analysis.

Object The aim of this study was to determine whether ictal single-photon emission computed tomography (SPECT) is useful in localizing the site of seizure onset in patients in whom surgery for intractable epilepsy failed and who are being considered for repeated surgery. Methods Subtraction ictal SPECT coregistered to magnetic resonance imaging (SISCOM) studies were retrospectively analyzed in 58 patients who were being evaluated for possible repeated resection for intractable partial epilepsy between January 1, 1996, and October 31, 1999. All patients had persistent seizures subsequent to an initial resection and underwent another excision. The SISCOM-demonstrated abnormalities were classified as concordant, discordant, or indeterminate, compared with the localization of the epileptogenic zone revealed on video electroencephalography monitoring. The ability of SISCOM to predict operative outcome was also determined in patients who had undergone repeated surgical procedures. The SISCOM studies revealed a localized hyperperfused alteration in 46 (79%) of 58 patients. Forty-one (89%) of these 46 patients had a SISCOM-demonstrated alteration in the hemisphere of the previous epilepsy surgery. Imaging changes in 33 (72%) of the 46 patients were at the site of the previous focal cortical resection. Eight (17%) of the 46 had SISCOM-demonstrated abnormalities remote from the lobe in which surgery had been performed but in the ipsilateral hemisphere. The hyperperfusion focus was in the contralateral hemisphere in the remaining five patients (11%). The site of the epileptogenic zone was concordant with the SISCOM focus in 32 (70%) of 46 patients. Twenty-six patients underwent repeated resection and were followed up for a mean of 44 months thereafter; 11 of these patients (42%) had a significant reduction in seizure tendency. Only five patients (19%) were seizure free. Ten (50%) of 20 patients with a concordant SISCOM focus compared with none (0%) of three patients with a discordant focus had a favorable surgical outcome (p = 0.23). Conclusions The SISCOM method might be useful in the evaluation of, and the surgical planning for, patients with intractable partial epilepsy in whom previous resective treatment has failed and who are being considered for reoperation.

Parathyroid scintigraphy (PS) may be used to localize hyperactive parathyroid glands preoperatively. Performance of PS in the setting of secondary and tertiary hyperparathyroidism (HPT) is not well quantified. The performance of PS in secondary/tertiary HPT versus primary HPT may reflect physiologic as well as radiopharmaceutical kinetic differences between multigland hyperplasia versus adenoma. The aim of this study was to review the performance of PS in secondary/tertiary HPT with a comparison to that for primary HPT. Moreover, we evaluated (1) the sensitivity of PS in detecting enlarged glands, and (2) PS detectability as a function of gland weight.We performed a retrospective review of the Mayo Clinic database from 2000 to 2004. We identified 40 patients with secondary or tertiary HPT as well as a matched control group of 40 patients with primary HPT who had had preoperative PS and underwent parathyroid surgery.Parathyroid scintigraphy correctly localized all enlarged glands in 88% of patients in the primary HPT group. PS correctly identified both the number and locations of all hyperplastic glands in only 28% of the secondary/tertiary HPT patients. PS failed to identify one enlarged gland in 23% of the patients and two or more enlarged glands in 40% of the patients. PS correctly detects the largest gland in 88% of the patients with secondary and tertiary HPT. The mean gland weight detectable by PS was 612 +/- 120 mg for primary HPT. In secondary/tertiary HPT, glands detected by PS had a mean weight of 950 +/- 109 mg, whereas the mean weight was 276 +/- 34 mg for undetected glands (P0.002).Parathyroid scintigraphy is a sensitive study for localizing parathyroid glands preoperatively in primary HPT patients. Its sensitivity is low in secondary and tertiary HPT patients. Thus PS has limited value as a preoperative localization study in secondary/tertiary HPT patients.

Selected patients with primary hyperparathyroidism (pHPT) who have a positive preoperative sestamibi scan can be managed safely and successfully with a focused cervical exploration without either adjuvant intraoperative parathyroid hormone (PTH) monitoring or use of a gamma probe. This article reports a retrospective analysis of a consecutive series of patients surgically treated at a tertiary referral center. From August 1998 to August 2002, 100 patients (68 women, 32 men; mean age 63 years [range: 29–89 years]) underwent a focused cervical approach without intraoperative PTH monitoring or use of the gamma probe after perioperative sestamibi injection. The study group comprised 9% of all patients (n = 1063) undergoing cervical exploration for pHPT during the study period. Ninety patients underwent an initial exploration, and 10 others underwent repeat cervical exploration following prior parathyroid (n = 7) or thyroid (n = 3) operation. Sestamibi scanning correlated with one enlarged parathyroid gland in all patients. Other enlarged glands were, however, not demonstrated in three patients (true positive = 97%; false negative = 3%). The single enlarged glands excised in all patients had a mean weight of 795 mg (range: 90–3640) and were histologically compatible with an adenoma. Postoperatively, 97% of patients were eucalcemic. Three patients remained hypercalcemic (3%). Of the three patients with persistent hypercalcemia, one underwent successful re-exploration with excision of a 500 mg second adenoma, whereas the other two patients (with confirmed familial HPT) remained hypercalcemic. Mean hospitalization was 0.5 days (range: 0–3 days). There was no operative mortality. No patients had permanent hypocalcemia. Postoperative morbidity occurred in three patients: two self-limiting cervical hematomas and one permanent vocal cord paralysis. Selected patients with pHPT due to single-gland disease and an unequivocally positive preoperative sestamibi scan can safely and successfully be managed with a focused unilateral cervical exploration without either intraoperative PTH monitoring or use of the gamma probe. Further experience with this surgical approach seems warranted to determine the overall cure rate, operative morbidity, and the sensitivity and specificity of preoperative localization studies.