Nuclear Scintigraphy in Practice: Gastrointestinal Motility.

OBJECTIVE: The purpose of this article is to describe the clinical utility of state-of-theart gastrointestinal transit scintigraphy, including the standardized esophageal transit, solid and liquid gastric emptying, small-bowel transit, colon transit, and whole-gut transit scintigraphy, with an emphasis on procedure performance. CONCLUSION: Radionuclide gastrointestinal motility studies are noninvasive, quantitative, and physiologic diagnostic tools for evaluating patients with gastrointestinal complaints.

Utility of sedation for young children undergoing dimercaptosuccinic acid renal scans.

BACKGROUND: No studies have examined whether use of sedation during a Tc-99 m dimercaptosuccinic acid (DMSA) renal scan reduces patient discomfort. OBJECTIVE: To compare discomfort level during a DMSA scan to the discomfort level during other frequently performed uroradiologic tests, and to determine whether use of sedation during a DMSA scan modifies the level of discomfort. MATERIALS AND METHODS: We examined the discomfort level in 798 children enrolled in the Randomized Intervention for children with Vesicoureteral Reflux (RIVUR) and Careful Urinary Tract Infection Evaluation (CUTIE) studies by asking parents to rate their child's discomfort level with each procedure on a scale from 0 to 10. We compared discomfort during the DMSA scan and the DMSA image quality between centers in which sedation was used >90% of the time (sedation centers), centers in which sedation was used <10% of the time (non-sedation centers), and centers in which sedation was used on a case-by-case basis (selective centers). RESULTS: Mean discomfort level was highest for voiding cystourethrogram (6.4), followed by DMSA (4.0), followed by ultrasound (2.4; P<0.0001). Mean discomfort level during the DMSA scan was significantly higher at non-sedation centers than at selective centers (P<0.001). No difference was apparent in discomfort level during the DMSA scan between sedation centers and selective centers (P=0.12), or between the sedation centers and non-sedation centers (P=0.80). There were no differences in the proportion with uninterpretable DMSA scans according to sedation use. CONCLUSION: Selective use of sedation in children 12-36 months of age can reduce the discomfort level experienced during a DMSA scan.

Relationship Between Gastrointestinal Transit, Medsger Gastrointestinal Severity, and University of California-Los Angeles Scleroderma Clinical Trial Consortium Gastrointestinal Tract 2.0 Symptoms in Patients With Systemic Sclerosis.

OBJECTIVE: Systemic sclerosis (SSc)-associated gastrointestinal (GI) complications are attributed to a variety of factors, including diet, microbiota dysbiosis, or GI transit abnormalities. Our objective was to examine the contribution of abnormal GI transit to SSc Medsger GI severity scores and/or University of California Los Angeles Scleroderma Clinical Trial Consortium Gastrointestinal Tract (UCLA GIT) 2.0 symptoms. METHODS: Patients with SSc and GI symptoms (n = 71) and healthy controls (n = 18) underwent whole gut transit (WGT) scintigraphy to assess transit from the esophagus to the colon. The presence of delayed transit and percent emptying in each GI region were measured. We compared the WGT measurements between categories of the Medsger GI severity score (0-4) and across UCLA GIT 2.0 domains and total score (0-3). RESULTS: A total of 88% of patients had >1 abnormal region of the gut on WGT scintigraphy. All patients requiring total parenteral nutrition had delayed small bowel transit, compared to only approximately 11% of patients in other Medsger GI severity groups (P ≤ 0.01). Severe colonic transit delays were more likely in patients with Medsger GI scores of 3 (pseudo-obstruction and/or malabsorption) compared to other Medsger GI groups (P = 0.02). Seventy-percent of these patients had ≤30% colonic emptying at 72 hours. Modest associations were noted between gastroesophageal reflux disease symptoms and delayed esophageal (r = -0.31, P = 0.05) and gastric emptying (r = -0.32, P = 0.05). CONCLUSION: These data are important in providing evidence that SSc bowel disease affects transit of GI content and that delay in transit accounts in part for both bowel symptoms and Medsger GI severity. Prospective studies examining the benefit of early therapeutic intervention targeting GI transit abnormalities in patients at high risk for severe GI complications are needed.

Experience with Esophagogastrointestinal Transit Scintigraphy in the Initial 229 Patients: Multiple Regions of Dysmotility Are Common.

The purpose of this investigation was to review our experience with our comprehensive esophagogastrointestinal transit study in the first 229 patients. This scintigraphic study analyzes the motility of the entire gut, from the esophagus through the rectosigmoid colon. Methods: Data were reviewed for our first 2 y of experience with this examination (184 women and 45 men aged 20-79 y [mean ± SD, 44 ± 16 y]). Patients were referred with symptoms suggestive of a motility disorder. They first swallowed 111In-diethylenetriaminepentaacetic acid in water for the esophageal-swallow study and then 300 mL for a 30-min 111In water-only study, followed by 120 mL of 111In water simultaneously with the solid standardized 99mTc egg-substitute meal. Images and quantification were obtained for esophageal transit, water-only gastric emptying, water-with-solid gastric emptying, small-bowel transit, and colonic transit. Results: Of the 229 patient studies, 45 (20%) were normal. The remaining 184 (80%) had at least 1 region of dysmotility, for a total of 336 regions of abnormal motility. A single region of dysmotility was seen in 92 patients (50%), 2 regions in 50 (27%), 3 regions in 26 (14%), 4 regions in 12 (7%), and 5 regions in 4 (2%). There was a poor correlation between the results of the water-only study and water with the solid meal. Three different patterns of delayed colonic transit were seen. Patient symptoms were often not predictive of the scintigraphic findings. Conclusion: This study highlights the frequent occurrence of dysmotility in more than 1 region of the gastrointestinal tract in patients with a suspected motility disorder and the frequent concurrence of both upper- and lower-tract dysmotility in the same patients. It provides information to referring physicians regarding which motility disorders may be causing the patient symptoms, why the patient is or is not responding to the present therapy, and if and what additional workup and therapy may be needed.

Nuclear medicine hepatobiliary imaging.

Nuclear medicine hepatobilary imaging (HIDA) is a time proven imaging methodology that uses radioactive drugs and specialized cameras to make imaging diagnoses based on physiology. HIDA radiopharmaceuticals are extracted by hepatocytes in the liver and cleared through the biliary system similar to bilirubin. The most common indication for HIDA imaging is acute cholecystitis, diagnosed by nonfilling of the gallbladder due to cystic duct obstruction. HIDA can detect high grade biliary obstruction prior to ductal dilatation; images reveal a persistent hepatogram without biliary clearance due to the high backpressure. HIDA also aids in the diagnosis of partial biliary obstruction due to stones, biliary stricture, and sphincter of Oddi obstruction. It can confirm biliary leakage postcholecystectomy and hepatic transplantation. Calculation of a gallbladder ejection fraction after cholecystokinin infusion is commonly used to diagnose chronic acalculous gallbladder disease. Diseased gallbladders do not contract. There are many other less common but valuable diagnostic indications for HIDA imaging.

Phase II study of risk-adapted therapy of newly diagnosed, aggressive non-Hodgkin lymphoma based on midtreatment FDG-PET scanning.

In newly diagnosed aggressive non-Hodgkin lymphoma (NHL), a positive midtreatment fluorine-18 fluorodeoxyglucose positron emission tomography (PET) scan often carries a poor prognosis, with reported 2-year event-free survival (EFS) rates of 0% to 30% after standard therapy. To determine the outcome of early treatment intensification for midtreatment PET-positive disease, a phase II trial of risk-adapted therapy was conducted. Fifty-nine newly diagnosed patients, 98% with B cell lymphoma, had PET/CT performed after 2 or 3 cycles of first-line chemotherapy. Those with negative PET on semiquantitative visual interpretation completed standard therapy. Those with positive PET received platinum-based salvage chemotherapy, high-dose therapy, and autologous stem cell transplantation (ASCT). Midtreatment PET was positive in 33 (56%); 28 received ASCT with an actuarial 2-year EFS of 75% (95% confidence interval, 60%-93%). On intention-to-treat analysis, 2-year EFS was 67% (53%-86%) in all PET-positive patients and 89% (77%-100%) in PET-negative patients. No association was found between the International Prognostic Index category and the midtreatment PET result. The favorable outcome achieved here in historically poor-risk patients warrants further, more definitive investigation of treatment modification based on early PET scanning.

The added diagnostic value of liquid gastric emptying compared with solid emptying alone.

UNLABELLED: The medical literature states that solid gastric-emptying studies are more sensitive for the detection of gastroparesis than are liquid studies; thus, liquid studies are rarely required. However, we have seen patients with normal solid but delayed liquid emptying. The purpose of this investigation was to determine whether a study of clear liquid gastric emptying has added value for the diagnosis of gastroparesis over a study of solid emptying alone. METHODS: A total of 101 patients underwent both solid and liquid gastric-emptying studies, acquired sequentially on the same day. A 30-min (1-min frames) liquid study (300 mL of water with 7.4 MBq [0.2 mCi] of (111)In-diethylenetriaminepentaacetic acid) was followed by a standardized 4-h solid-meal study (a (99m)Tc-sulfur colloid-labeled egg-substitute sandwich meal). Emptying was quantified as a best-fit exponential emptying rate (T1/2) for liquids and percentage emptying at 4 h for solid emptying. Thirty healthy volunteers underwent a study of clear liquid emptying to establish normal values. The results of the liquid and solid studies were compared. (111)In liquid downscatter into the subsequent (99m)Tc solid meal results was analyzed. RESULTS: The upper range of normal for clear liquid emptying (T1/2) for healthy volunteers was 22 min (mean +/- 3 SDs) and 19 min (mean +/- 2 SDs). Of 101 patients, delayed emptying was found in 36% of liquid and 16% of solid studies. Of all patients with normal solid emptying, 32% had delayed liquid emptying. (111)In downscatter into the (99m)Tc window was not generally significant. CONCLUSION: For the detection of gastroparesis, a 30-min study of clear liquid gastric-emptying has considerable added diagnostic value over a study of solid emptying alone.

Importance of methodology on (99m)technetium dimercapto-succinic acid scintigraphic image quality: imaging pilot study for RIVUR (Randomized Intervention for Children With Vesicoureteral Reflux) multicenter investigation.

PURPOSE: We reviewed our experience with (99m)technetium dimercapto-succinic acid scintigraphy obtained during an imaging pilot study for a multicenter investigation (Randomized Intervention for Children With Vesicoureteral Reflux) of the effectiveness of daily antimicrobial prophylaxis for preventing recurrent urinary tract infection and renal scarring. We analyzed imaging methodology and its relation to diagnostic image quality. MATERIALS AND METHODS: (99m)Technetium dimercapto-succinic acid imaging guidelines were provided to participating sites. High-resolution planar imaging with parallel hole or pinhole collimation was required. Two core reviewers evaluated all submitted images. Analysis included appropriate views, presence or lack of patient motion, adequate magnification, sufficient counts and diagnostic image quality. Inter-reader agreement was evaluated. RESULTS: We evaluated 70, (99m)technetium dimercapto-succinic acid studies from 14 institutions. Variability was noted in methodology and image quality. Correlation (r value) between dose administered and patient age was 0.780. For parallel hole collimator imaging good correlation was noted between activity administered and counts (r = 0.800). For pinhole imaging the correlation was poor (r = 0.110). A total of 10 studies (17%) were rejected for quality issues of motion, kidney overlap, inadequate magnification, inadequate counts and poor quality images. The submitting institution was informed and provided with recommendations for improving quality, and resubmission of another study was required. Only 4 studies (6%) were judged differently by the 2 reviewers, and the differences were minor. CONCLUSIONS: Methodology and image quality for (99m)technetium dimercapto-succinic acid scintigraphy varied more than expected between institutions. The most common reason for poor image quality was inadequate count acquisition with insufficient attention to the tradeoff between administered dose, length of image acquisition, start time of imaging and resulting image quality. Inter-observer core reader agreement was high. The pilot study ensured good diagnostic quality standardized images for the Randomized Intervention for Children With Vesicoureteral Reflux investigation.

Liquid gastric emptying is often abnormal when solid emptying is normal.

BACKGROUND: The medical literature states that solid radionuclide gastric emptying studies are more sensitive than liquid studies for detection of gastroparesis and thus liquid studies are rarely indicated. At our institution, patients are often referred for both studies. Our initial purpose was to review the results in those patients. The surprising results led us to initiate a prospective investigation to more directly determine the relative value of solid versus liquid emptying studies. METHODS: The retrospective review included 21 patients who had both studies performed on separate days. The subsequent prospective investigation was initiated so that the solid and liquid emptying studies were acquired sequentially on the same day. A total of 40 consecutive patients with symptoms suggestive of gastroparesis (mean age 44.8, 12 males, 28 females) were investigated. All ingested 300 mL water with radiotracer and were imaged each minute 30. They then ingested the radiolabeled solid meal and were imaged each hour 4. A liquid emptying rate (T1/2) and solid percent emptying each hour 4 was determined. RESULTS: In the retrospective review, 17 of 21 patients had normal solid emptying; of those, 13 had delayed liquid emptying. In the subsequent prospective study, 30/40 (75%) had normal solid emptying; of those, 10 (33%) had delayed liquid emptying. Nine patients (23%) had delayed solid emptying; 13 (32%) had delayed liquid emptying. CONCLUSIONS: Liquid gastric emptying is commonly abnormal in patients who have normal solid studies. Liquid studies should be routinely performed in addition to solid studies to fully evaluate gastric motility in patients with symptoms suggestive of gastroparesis.

Comparison of 99mTc-DMSA dual-head SPECT versus high-resolution parallel-hole planar imaging for the detection of renal cortical defects.

OBJECTIVE: Renal cortical scintigraphy with (99m)Tc dimer captosuccinic acid (DMSA) is the standard method to detect acute pyelonephritis and cortical scarring. Different acquisition methods have been used: planar parallel-hole or pinhole collimation and single photon emission tomography (SPECT). Publications support the superiority of each; few comparative studies have been reported, with mixed results. We have compared planar parallel-hole cortical scintigraphy and dual-head SPECT for detection of cortical defects. MATERIALS AND METHODS: Forty patients (37 children, 3 adults; 9 male, 31 female) were imaged 3 hours after injection of (99m)Tc-DMSA with dual-head SPECT and planar imaging (posterior, left, and right posterior oblique views with a parallel-hole collimator). For each patient, planar and SPECT images were evaluated at different sittings, in random order, by three independent observers. Twelve cortical segments were scored as normal or reduced uptake. The linear correlation coefficient for the number of abnormal segments detected between readers, techniques, and segments was calculated. RESULTS: No significant difference was seen in the average number of abnormal segments detected by planar versus SPECT imaging; 2.1 for planar imaging and 2.2 for SPECT (p = 0.84, two-tailed). For all observers, the average correlation coefficient for SPECT alone, planar imaging alone, and between techniques (SPECT vs planar imaging) was high (r = 0.93-0.94). Applying nonparametric Spearman's rank analysis, the average correlation remained high (r = 0.70-0.75). Correlation between readers, techniques, and segments for methods and readers was also good (r = 0.69-0.77). CONCLUSION: (99m)Tc-DMSA renal cortical imaging using dual-head SPECT offers no statistically significant diagnostic advantage over planar imaging for detection of cortical defects.

Sincalide: A Review of Clinical Utility, Proper Infusion Methodology, and Alternative Cholecystogogues.

Sincalide (Kinevac) is widely used in conjunction with cholescintigraphy for a variety of clinical indications. Over the years, numerous publications have verified the optimal infusion methodology. Published data and consensus recommendations emphasize that sincalide, 0.02 µg/kg, should be infused over 60 min. Production problems sometimes limit the availability of sincalide. In that case, non-Food and Drug Administration pharmacy-compounded sincalide may serve as an alternative. Fatty meals have also been used. Various illnesses and drugs may inhibit gallbladder contraction. Thus, these drugs should be withheld for 48 h before the study. Sincalide cholescintigraphy is most commonly used to diagnose or exclude chronic acalculous gallbladder disease. The study should preferably be performed as an outpatient procedure.

EnsurePlus as an Alternative to the Standardized Egg Gastric-Emptying Meal.

OBJECTIVES: The purpose of this study was to establish normal gastric-emptying values for EnsurePlus in healthy subjects and to determine whether it is an acceptable alternative to the recommended standardized Tc-sulfur colloid egg meal. METHODS: Twenty-one healthy subjects underwent gastric-emptying scintigraphy with In-DTPA EnsurePlus. Normal gastric emptying values were established for 1, 2, 3, and 4 hours after meal ingestion. The gastric-emptying results were compared with another group of normal subjects (n = 18) who ingested the standardized egg meal. RESULTS: The mean (95% upper reference limit) percentages for gastric retention for EnsurePlus were as follows: 69.9% (87.1%) at 1 hour, 35.1% (64.3%) at 2 hours, 13.5% (23.2%) at 3, and 8.9% (13.5%) at 4 hours. There were time-related differences in the gastric emptying of the EnsurePlus compared with the egg meal. In the first and second hours, there were no difference between EnsurePlus and the egg meal in terms of percentage retention (P = 0.92 at 1 hour, P = 0.05 at 2 hours). However, at 3 and 4 hours after meal ingestion, the mean percentage gastric retention of the EnsurePlus was significantly higher than the egg meal (P < 0.001). CONCLUSION: EnsurePlus is a good and acceptable alternative to the standardized egg meal.

Visualization of brown adipose tissue with 99mTc-methoxyisobutylisonitrile on SPECT/CT.

UNLABELLED: Brown adipose tissue (BAT) is retained into adulthood in some patients. It has been imaged using several radiopharmaceuticals, including (18)F-FDG. Using SPECT/CT, we assessed whether and how frequently uptake of (99m)Tc-methoxyisobutylisonitrile ((99m)Tc-MIBI) was present in expected locations of BAT. METHODS: A total of 205 SPECT/CT scans using (99m)Tc-MIBI for parathyroid imaging were reviewed for the presence of (99m)Tc-MIBI uptake in expected locations of BAT. RESULTS: We detected (99m)Tc-MIBI uptake in BAT in 13 of 205 patients (6.3%). When BAT was visualized, it was detected on both early and delayed scans. The patients with (99m)Tc-MIBI uptake in BAT were younger than the patients with no (99m)Tc-MIBI uptake (P=0.044). CONCLUSION: Uptake of (99m)Tc-MIBI in BAT is relatively common in this adult patient population and should not be confused with (99m)Tc-MIBI-avid-tumors. SPECT/CT can be useful for defining such tracer uptake as a normal physiologic variant.

Parathyroid scintigraphy in patients with primary hyperparathyroidism: 99mTc sestamibi SPECT and SPECT/CT.

The clinical diagnosis of primary hyperparathyroidism is based largely on serum laboratory test results, as patients often are asymptomatic. Surgery, often with bilateral exploration of the neck, has been considered the definitive treatment for symptomatic disease. However, given that approximately 90% of cases are due to a single parathyroid adenoma, a better treatment may be the selective surgical excision of the hyperfunctioning parathyroid gland after its preoperative identification and localization at radiologic imaging. Scintigraphy and ultrasonography are the imaging modalities most often used for preoperative localization. Various scintigraphic protocols may be used in the clinical setting: Single-phase dual-isotope subtraction imaging, dual-phase single-isotope imaging, or a combination of the two may be used to obtain planar or tomographic views. Single photon emission computed tomography (SPECT) with the use of technetium-99m ((99m)Tc) sestamibi as the radiotracer, especially when combined with x-ray-based computed tomography (CT), is particularly helpful for preoperative localization: The three-dimensional functional information from SPECT is fused with the anatomic information obtained from CT. In addition, knowledge of the anatomy and embryologic development of the parathyroid glands and the pathophysiology of primary hyperparathyroidism aid in the identification and localization of hyperfunctioning glands.

Consensus recommendations for gastric emptying scintigraphy: a joint report of the American Neurogastroenterology and Motility Society and the Society of Nuclear Medicine.

This consensus statement from the members of the American Neurogastroenterology and Motility Society and the Society of Nuclear Medicine recommends a standardized method for measuring gastric emptying (GE) by scintigraphy. A low-fat, egg-white meal with imaging at 0, 1, 2, and 4 h after meal ingestion, as described by a published multicenter protocol, provides standardized information about normal and delayed GE. Adoption of this standardized protocol will resolve the lack of uniformity of testing, add reliability and credibility to the results, and improve the clinical utility of the GE test.

The Scintigraphic Drooping Lily Sign.

The "drooping lily" sign is identified on intravenous urography or voiding cystourethrography in patients with a duplicated renal collecting system and refers to inferolateral displacement of a functioning lower pole moiety by an obstructed upper pole collecting system. In this case, a 2-month-old girl with a prenatal diagnosis of hydronephrosis was found to have a "scintigraphic drooping lily" sign on Tc-dimercaptosuccinic acid renal scan. Evaluation with ultrasound and voiding cystourethrography confirmed a duplicated collecting system and obstructed upper pole moiety. Correlation with anatomic imaging can help avoid mistaking the scintigraphic "drooped" lower pole for an inferiorly positioned normal kidney.

Experience with a simplified, standardized 4-hour gastric-emptying protocol.

UNLABELLED: Gastric-emptying studies have no accepted standard methodology or reference values. A simplified standardized protocol with a large reference database has been proposed, with imaging obtained at only 0, 1, 2, and 4 h. The rationale for its 4-h length is data suggesting that delayed emptying is detected with higher sensitivity at 4 h than at 2 h. The purpose of the current investigation was to review our 2-y experience using this protocol, to determine the added value of 4-h imaging, and to determine whether the lag phase can predict delayed emptying. METHODS: After ingesting a sandwich made with (99m)Tc-sulfur colloid egg substitute, 175 patients were imaged immediately, every 10 min for 1 h, and then at 2, 3, and 4 h. Percentage retention was calculated for each interval. Sensitivities, specificities, predictive values, and receiver operating characteristic (ROC) curves were computed for the 1-, 2-, and 3-h intervals on the basis of normal 4-h values. Data were analyzed to determine the added value of the 4-h study. Thresholds were sought that optimized accuracy. ROC analysis was used to determine the predictive value of the lag phase. RESULTS: Gastric emptying was delayed in 20% of patients at 2 h and in 26% at 4 h, a 29% increase in abnormal studies (P < 0.02). Of those normal at 2 h, 13% became abnormal at 4 h. Of those with delayed emptying at 2 h, 24% normalized at 4 h. Compared with the study at 4 h, the study at 2 h had a 59% sensitivity, 94% specificity, 76% PPV, and 87% NPV. ROC analysis showed that the areas under the ROC curve (AUC) were 0.75, 0.93, and 0.97 at 1, 2, and 3 h, respectively. The threshold for optimal accuracy for 3-h data was estimated to be greater than 30% retention. The accuracy of this threshold was 91%. The lag phase AUC for predicting delayed emptying at 4 h was 0.60. CONCLUSION: This first investigation of a large referral patient population using a standardized protocol found that abnormal emptying is detected with greater sensitivity at 4 h than at 2 h and that the lag phase is not predictive of delayed emptying.

Comparison of SPECT/CT, SPECT, and planar imaging with single- and dual-phase (99m)Tc-sestamibi parathyroid scintigraphy.

UNLABELLED: Various methodologies for (99m)Tc-sestamibi parathyroid scintigraphy are in clinical use. There are few direct comparisons between the different methods and even less evidence supporting the superiority of one over another. Some reports suggest that SPECT is superior to planar imaging. The addition of CT to SPECT may further improve parathyroid adenoma localization. The purpose of our investigation was to compare hybrid SPECT/CT, SPECT, and planar imaging and to determine whether dual-phase imaging is advantageous for the 3 methodologies. METHODS: Scintigraphy was performed on 110 patients with primary hyperparathyroidism and no prior neck surgery. Of these, 98 had single adenomas and are the subject of this review. Planar imaging and SPECT/CT were performed at 15 min and 2 h after injection. Six image sets (early and delayed planar imaging, SPECT, and SPECT/CT) and combinations of the 2 image sets were reviewed for adenoma localization at 13 possible sites. Each review was scored for location and certainty of focus by 2 reviewer groups. Surgical location served as the standard. Sensitivity, specificity, area under the curve, positive predictive value, negative predictive value, and kappa-values were determined for each method. RESULTS: The overall kappa-coefficient (certainty of adenoma focus) between reading groups was 0.68 (95% confidence interval, 0.66-0.70). The highest values were for dual-phase studies that included SPECT/CT. Dual-phase planar imaging, SPECT, and SPECT/CT were statistically significantly superior to single-phase early or delayed imaging in sensitivity, area under the curve, and positive predictive value. Neither single-phase nor dual-phase SPECT was statistically superior to dual-phase planar imaging. Early-phase SPECT/CT in combination with any delayed imaging method was superior to dual-phase planar imaging or SPECT for sensitivity, area under the curve, and positive predictive value. CONCLUSION: Early SPECT/CT in combination with any delayed imaging method was statistically significantly superior to any single- or dual-phase planar or SPECT study for parathyroid adenoma localization. Localization with dual-phase acquisition was more accurate than with single-phase (99m)Tc-sestamibi scintigraphy for planar imaging, SPECT, and SPECT/CT.

Indium-111 diethylene-triamine-pentaacetic acid scintigraphy in the evaluation of function and patency of baclofen intrathecal infusion systems.

OBJECT: Baclofen pump infusion systems are used for the treatment of patients with severe spasticity. When symptoms do not respond to infusion rate increases, the cause may be pump malfunction or catheter obstruction. The purpose of this investigation was to review the authors' experience with indium-111 diethylene-triamine-pentaacetic acid (In-111 DTPA) scintigraphy for evaluation of baclofen infusion system function and patency and to correlate scintigraphic findings with patient treatment and outcome to determine optimal methodology and diagnostic criteria. METHODS: Ten scintigraphic studies acquired in eight patients (five adults, three adolescents) were retrospectively reviewed. Imaging was routinely performed at 4, 24, 48, and 72 hours after injection of In-111 DTPA into the pump reservoir. The results of the studies were interpreted by two nuclear medicine physicians who had no knowledge of the patients' clinical history or outcome. The scintigraphic findings (for example, radiotracer detected in the basal cisterns, cervical or thoracolumbar regions, infusion catheter, and pump) were recorded and correlated with neuroimaging findings, patient history, treatment, and clinical response to therapy. RESULTS: In cases in which the basal cistern could be visualized at any time and those in which radiotracer was visualized in the thoracolumbar intrathecal region within 48 hours, the pump systems were functional and symptoms responded to an increase in infusion rate. One patient in whom activity was visualized in the thoracolumbar intrathecal region by 72 hours also experienced clinical improvement with a flow rate increase. Visualization of the pump alone or only the pump and the subcutaneous catheter was consistent with catheter obstruction or pump malfunction. CONCLUSION: The use of In-111 DTPA scintigraphy of intrathecal baclofen infusion systems can play an important role in determining the functional status of these systems and guiding subsequent patient care.