1375 Background: In staging pancreatic ductal adenocarcinoma (PDAC), PET/CT and contrast-enhanced MR currently serve as problem-solving tools for detecting metastatic disease1, particularly small hepatic metastases that may not be accurately characterized on traditional multiphase contrast enhanced CT. Recently, PET/MR has performed similarly to PET/CT in detecting metastases2, however, is not widely available and therefore not routinely used in clinical practice. Since 2018, our institution has performed over 70 PET/MR studies in patients with PDAC using a protocol with both free-breathing PET acquisition from the skull to the thighs, as well as respiratory-gated (RG) PET acquisition of the abdomen obtained simultaneously with RG MR sequences. We hypothesize that the addition of RG PET acquisition (Q.Static, GE Healthcare) provides greater liver lesion conspicuity, decreased background liver heterogeneity, and improved detection of liver metastases without increasing scan time. Methods: Adult patients evaluated on a GE Signa PET/MR scanner for staging of pancreatic adenocarcinoma from 9/11/2018 to 9/17/2020 were screened, with 75 PET/MR studies performed on 72 patients. Seventeen studies interpreted as positive for liver metastases were included, as well as 10 negative studies as controls. Measurements of background liver SUV maximum (SUVmax), SUV average (SUVavg), and SUV standard deviation (SUVstd) were compared between respiratory-gated (RG) and free-breathing (FB) acquisitions, as was lesion SUVmax. Studies were randomized and evaluated by nuclear medicine trained radiologists (5 attending radiologists, 1 fellow), with only PET images visible. Readers were blinded to acquisition type and identified the number of “definite” and “possible” lesions. Results: Respiratory-gated PET demonstrated decreased background liver FDG uptake compared to FB PET, with a mean SUVmax of 3.24 versus 3.82 (P<.001), mean SUVavg of 2.59 versus 2.75 (P<.001), and mean SUVstd of 0.18 versus 0.27 (P<.001). No statistically significant difference was seen in lesion SUVmax between RG and FB acquisitions, with a mean SUVmax of 5.32 versus 5.02 (P=.05). There was a higher ratio of lesion SUVmax to background liver SUVmax on RG images, with a mean ratio of 1.69 versus 1.41 (P<.001). The ratio of lesion SUVmax to background liver SUVavg was also higher for RG, with a mean ratio of 2.17 versus 1.94 (P=.002). Readers identified more lesions on RG images, with a mean of 48 lesions across 27 studies, versus 30 on FB (P=.004). Lesions were identified with greater confidence on RG, with “definite” lesions comprising 64% of total lesions versus 49% (P=.015). Across the 17 positive studies, there were fewer false negative studies on RG, with an average of 0.5 versus 2.3 (P=.006). Across 10 negative studies, there was no difference in false positive lesions, with a mean of 3.3 and 3.2 on RG and FB, respectively (P=.915). Discussion: PET/MR is an emerging modality in the staging of pancreatic adenocarcinoma. Without increasing scan time, respiratory-gated PET acquisition decreases background noise in the liver, increases metastasis conspicuity, results in detection of more lesions with greater confidence with fewer false negatives. Our institution recommends inclusion of RG PET acquisition in PET/MR protocols for pancreatic adenocarcinoma staging. Figure 1. Respiratory-gated PET (right) demonstrating decreased background liver uptake and improved lesion conspicuity of a single liver metastasis when compared to free-breathing acquisition (left).

BACKGROUND:Upper abdominal irradiation for pancreatic cancer is administered in close proximity to the radiation-sensitive kidneys. There is difficulty in defining dose-volume parameters to predict late renal toxicity after partial kidney irradiation. Less than 10% of the general population is estimated to have asymmetrical kidney function; however, there are no studies that examine this in patients with pancreatic cancer. The primary purpose of this study was to determine the prevalence of asymmetrical kidney function in patients with pancreatic cancer. A secondary aim was to determine if asymmetrical kidney function was associated with abnormal laboratory values or kidney size on computed tomography scans. Finally, we aimed to develop recommendations for when a functional renal scan in patients with pancreatic cancer should be ordered. METHODS AND MATERIALS:We performed a retrospective review of patients with resectable, borderline resectable, and locally advanced pancreatic cancer who received abdominal radiation therapy and had preradiation functional renal scans between 2009 and 2015. Asymmetrical kidney function was defined as a difference between the 2 kidneys that was ≥60%/40% on a functional renal scan. Serum studies (blood urea nitrogen [BUN], creatinine [Cr], and glomerular filtration rate [GFR]) and abdominal computed tomography scans were routinely obtained before simulation. RESULTS:Of the 204 patients examined, 23 (11.2%) had asymmetrical kidney function that was identified on preradiation functional renal scans. Elevated Cr or BUN, a GFR <60, or a medical history that suggested abnormal renal function were not significantly associated with asymmetrical kidney function. Only 6 of 23 patients (26%) with asymmetrical kidney function had a notable difference in kidney size. CONCLUSIONS:In our series, approximately 11% of patients with pancreatic cancer have asymmetrical kidney function that was not identified by kidney size, serum BUN, Cr, GFR, or a significant medical history. These data suggest that in cases in which renal radiation doses exceed a V18 of 20% to 30% or there is concern about baseline renal function, a functional renal scan should be considered.

BACKGROUND:For patients with primary hyperparathyroidism (pHPT), imaging studies are obtained to facilitate minimally invasive parathyroidectomy. If imaging studies are nonlocalizing, it is not known if exploration should begin on a particular side or gland location. STUDY DESIGN:A retrospective review of a prospective parathyroid database was performed. The cohort consists of pHPT patients who underwent initial parathyroidectomy between December 1999 and July 2010 and had all preoperative imaging studies reported as nonlocalizing (negative or indeterminate). RESULTS:Of 880 patients, 151 (17%) had nonlocalizing imaging studies. Reasons for starting exploration on a particular side were identified in 78 (52%) patients and included concomitant thyroid pathology (53%), suspicion on surgeon re-review of imaging (38%), or earlier thyroidectomy (9%). Exploration began on the right in 52%, the left in 42%, and was unknown in 6%. The surgeon had suspicion on imaging in 30 patients and correctly started on the side of pathology in 19 (63%). Hyperfunctioning glands were in eutopic locations in 144 patients (95%) and 3 had intrathyroidal glands. In 111 patients (74%) with single gland disease, median adenoma weight was 320 mg (range 80 to 8,210 mg). There was no difference in adenoma laterality (p = 0.7) or location (p = 0.8). Intraoperative parathyroid hormone criteria were met in 145 (96%) patients and 149 are eucalcemic at last follow-up; 2 (0.7%) patients have persistent disease. CONCLUSIONS:In pHPT patients with nonlocalizing imaging, hyperfunctioning glands are not more frequently located on a particular side or anatomic position. Eutopic location is common and intraoperative parathyroid hormone monitoring should be used to guide the extent of surgery.

OBJECTIVE The purpose of this study was to evaluate the equivalence of CT pulmonary angiography and perfusion scanning in terms of diagnostic quality and negative predictive value in the imaging of pulmonary embolism (PE) in pregnancy. MATERIALS AND METHODS Between 2000 and 2007 at a university hospital and a large private hospital, 199 pregnant patients underwent 106 CT pulmonary angiographic examinations and 99 perfusion scans. Image quality was evaluated, and the findings were reread by radiologists and compared with the original clinical readings. Three-month follow-up findings of PE and deep venous thrombosis were recorded. RESULTS PE was found in four of the 106 patients (3.7%) who underwent CT pulmonary angiography. The overall image quality was poor in 5.6% of cases, acceptable in 17.9%, and good in 76.4%. Fourteen CT and nine radiographic studies showed other clinically significant abnormalities. Six patients had indeterminate CT pulmonary angiographic findings, three had normal perfusion scans, and none underwent anticoagulation. All perfusion scan findings were normal. There was one incomplete study, and follow-up CT pulmonary angiography performed the same day showed PE. Two of 99 studies (2.02%) showed intermediate probability of the presence of PE; PE was not found at CT pulmonary angiography, but pneumonia was found. PE was found in one postpartum patient 9 weeks after she had undergone CT pulmonary angiography and ultrasound with normal findings. None of the patients died. CONCLUSION CT pulmonary angiography and perfusion scanning have equivalent clinical negative predictive value (99% for CT pulmonary angiography; 100% for perfusion scanning) and image quality in the care of pregnant patients. Therefore, the choice of study should be based on other considerations, such as radiation concern, radiographic results, alternative diagnosis, and equipment availability. Reducing the amount of radiation to the maternal breast favors use of perfusion scanning when the radiographic findings are normal and there is no clinical suspicion of an alternative diagnosis.

Purpose: We determined whether multidetector computerized tomography urography is sensitive and specific for detecting urinary tract neoplasms when used as the primary imaging modality for evaluating patients with hematuria.Materials and Methods: A retrospective review was performed of the radiological, urological and pathological records of 468 patients without a history of urinary neoplasms who presented with hematuria. All patients underwent multidetector computerized tomography urography and complete urological evaluation, including cystoscopy. Laboratory urinalysis and cytology were done in 350 and 318 of the 468 patients, respectively. Multivariate logistic regression analysis was performed using the variables multidetector computerized tomography urography diagnosis, worst urine cytology, number of red blood cells per high power field, gross hematuria, age and gender to predict urinary tract neoplasm.Results: A total of 50 urinary neoplasms were diagnosed in 468 patients. Multidetector computerized tomography urography detected 32 of 50 neoplasms for a sensitivity of 64%, specificity of 98%, positive predictive value of 76% and negative predictive value of 96%. There were 10 false-positive and 18 false-negative multidetector computerized tomography urography studies. Multivariate logistic regression showed that abnormal multidetector computerized tomography urography findings, ie neoplasm (p <0.0001), and suspicious or positive urine cytology (p = 0.0009) were significant. Patients with an abnormal multidetector computerized tomography urography diagnosis and suspicious or positive urine cytology had 44 and 47 times greater odds, respectively, of having urinary neoplasms compared to the odds in those with normal examinations.Conclusions: Multidetector computerized tomography urography is relatively sensitive and highly specific for detecting urinary neoplasms. It may serve as the primary imaging modality to evaluate patients with hematuria. Multidetector computerized tomography urography does not eliminate the role of cystoscopy in the evaluation of hematuria.

OBJECTIVE:The C2A domain of Synaptotagmin I is a molecular probe for the specific imaging of cell death. Here we test the hypothesis that the uptake of 99mTc-C2A in the acute phase of an infarction is associated with cardiac dysfunction in follow-ups. METHODS:The left coronary artery was occluded in Sprague-Dawley rats for 0, 10, 20, and 30 min. 99mTc-C2A was injected intravenously at 2 h of reperfusion. Anterior planar images were acquired with one million counts on a gamma camera 3 h after injection. 99mTc-C2A uptake was calculated as the total counts in the left ventricle region minus blood pool signal. The in-vivo signal detected was correlated with wall motion score index at 1 and 3 weeks follow-ups measured by echocardiography. RESULTS:99mTc-C2A uptake was higher with increased ischemic time (2244+/-852, 4054+/-1223, and 6178+/-1451 for 10, 20, and 30 min ischemia, analysis of variance P<0.001). A significant correlation was found between 99mTc-C2A uptake and wall motion score index at 1 week (R=0.800, P=0.0006) and 3 weeks (R=0.810, P=0.0008). CONCLUSION:In this ischemia/reperfusion model, 99mTc-C2A uptake in the acute phase was associated with functional abnormality at 1 and 3 weeks. This demonstrates the potential diagnostic and prognostic value of 99mTc-C2A as a novel imaging agent.

A 75-year-old woman with a long-standing history of smoking and emphysema presented with hoarseness and hemoptysis. Computed tomography (CT) scan found a large soft tissue mass involving the superior mediastinum and aortic-pulmonary window (Figure 1). Left main stem biopsy revealed small cell carcinoma. Apart from left vocal cord paralysis, no other laryngeal lesion was identified on bronchoscopy. Co-registered CT-Positron emission tomography (PET) fusion images identified physiologic fluorodeoxyglucose (FDG) uptake in the right vocal cord but no uptake in the left vocal cord (Figure 2).FIGURE 2Integrated CT-PET scan demonstrating physiologic FDG uptake in the right vocal cord but no uptake in the left vocal cord.View Large Image Figure ViewerDownload (PPT) Physiologic tracer uptake in the laryngeal muscles occurs during speech but not when a patient remains completely silent.1Kostakoglu L Wong JC Barrington SF et al.Speech-related visualization of laryngeal muscles with fluorine-18-FDG.J Nucl Med. 1996; 37: 1771-1773PubMed Google Scholar When the recurrent laryngeal nerve is paralyzed, the ipsilateral vocal fold is fixed in a paramedian position due to the unopposed action of the cricothyroid muscle innervated by the superior laryngeal nerve.2Hong KH Jung KS Arytenoid appearance and vertical level difference between the paralyzed and innervated vocal cords.Laryngoscope. 2001; 111: 227-232Crossref PubMed Scopus (30) Google Scholar The compensatory movement during phonation of the contralateral vocal cord results in increased workload, and leads to increased local glucose consumption. The combination of a left mediastinal mass with aorto-pulmonary window involvement or at the left lung apex (i.e., the anatomic course of the recurrent laryngeal nerve) and concomitant right-sided increased uptake in laryngeal muscles is a finding that can be seen in patients with recurrent left-sided laryngeal nerve palsy.3Kamel EM Goerres GW Burger C et al.Recurrent laryngeal nerve palsy in patients with lung cancer: detection with PET-CT image fusion–report of six cases.Radiology. 2002; 224: 153-156Crossref PubMed Scopus (67) Google Scholar Although FDG-PET is a sensitive imaging modality for lung cancer staging, anatomic localization of lesions detected at PET is suboptimal. Co-registered CT-PET fusion images allow the focal FDG uptake to be reliably localized to the small internal laryngeal muscles.

INTRODUCTION:The C2A domain of synaptotagmin I recognizes necrotic and apoptotic cells by binding to exposed anionic phospholipids. The goal is to explore the potential imaging utility of 99mTc-labeled C2A in the detection of acute cardiac cell death in a porcine model that resembles human cardiovascular physiology. METHODS:Ischemia (20-25 min) was induced in pigs (M/F, 20-25 kg) using balloon angioplasty. 99mTc-C2A-GST (n=7) or 99mTc-BSA (n=2) was injected intravenously 1-2 h after reperfusion. Noninfarct animals were injected with 99mTc-C2A-GST (n=4). SPECT images were acquired at 3 and 6 h postinjection. Cardiac tissues were analyzed to confirm the presence of cell death. RESULTS:Focal uptake was detected in five out of seven subjects at 3 h and in all infarct subjects at 6 h postinjection but not in infarct animals injected with 99mTc-BSA or in noninfarct animals with 99mTc-C2A-GST. Gamma counting of infarct versus normal myocardium yielded a 10.2+/-5.7-fold elevation in absolute radioactivity, with histologically confirmed infarction. CONCLUSIONS:We present data on imaging myocardial cell death in the acute phase of infarction in pigs. C2A holds promise and warrants further development as an infarct-avid molecular probe.

OBJECTIVE The purpose of this study was to determine whether a saline bolus during CT urography improves urinary collecting system opacification and whether the addition of enhanced CT digital radiography (CTDR) improves urinary collecting system visualization with or without a saline bolus. MATERIALS AND METHODS One hundred eight CT urography and enhanced CTDR examinations were reviewed. Fifty-four patients were given a saline bolus during CT urography, and 54 patients underwent CT urography without a saline bolus. Urinary collecting system opacification was evaluated by group (saline vs nonsaline), imaging technique (CT urography alone vs CT urography plus enhanced CTDR), number of enhanced CTDR images, and site of nonopacified urinary segments. Using a multivariate logistic regression model, we determined significance of variables and odds of complete opacification. RESULTS In the saline group, 248 nonopacified sites were identified on CT urography alone and 95 sites with CT urography plus enhanced CTDR. In the nonsaline group, 185 nonopacified sites were identified on CT urography alone and 59 sites with CT urography plus enhanced CTDR. Combining both groups, 433 nonopacified sites were identified with CT urography alone and 154 sites with CT urography plus enhanced CTDR. Multivariate logistic regression showed significance for group (p = 0.010), imaging method (p < 0.0001), number of enhanced CTDR images (p = 0.048), and site of segment opacification (p < 0.0001). The renal pelvis shows the greatest odds and the distal ureter the lowest odds for complete opacification by group or imaging method. CONCLUSION The addition of a saline bolus offers no improvement, whereas the addition of enhanced CTDR offers significant improvement in collecting system opacification during CT urography.

UNLABELLEDThe exposure of phosphatidylserine (PtdS) is a common molecular marker for both apoptosis and necrosis and enables the simultaneous detection of these distinct modes of cell death. Our aim was to develop a radiotracer based on the PtdS-binding activity of the C2A domain of synaptotagmin I and assess 99mTc-C2A-GST (GST is glutathione S-transferase) using a reperfused acute myocardial infarction (AMI) rat model.METHODSThe binding of C2A-GST toward apoptosis and necrosis was validated in vitro. After labeling with 99mTc via 2-iminothiolane thiolation, radiochemical purity and radiostability were tested. Pharmacokinetics and biodistribution were studied in healthy rats. The uptake of 99mTc-C2A-GST within the area at risk was quantified by direct gamma-counting, whereas nonspecific accumulation was estimated using inactivated 99mTc-C2A-GST. In vivo planar imaging of AMI in rats was performed on a gamma-camera using a parallel-hole collimator. Radioactivity uptake was investigated by region-of-interest analysis, and postmortem tetrazolium staining versus autoradiography.RESULTSFluorescently labeled and radiolabeled C2A-GST bound both apoptotic and necrotic cells. 99mTc-C2A-GST had a radiochemical purity of >98% and remained stable. After intravenous injection, the uptake in the liver and kidneys was significant. For 99mTc-C2A-GST, radioactivity uptake in the area at risk reached between 2.40 and 2.63 %ID/g (%ID/g is percentage injected dose per gram) within 30 min and remained plateaued for at least 3 h. In comparison, with the inactivated tracer the radioactivity reached 1.06 +/- 0.49 %ID/g at 30 min, followed by washout to 0.52 +/- 0.23 %ID/g. In 7 of 7 rats, the infarct was clearly identifiable as focal uptake in planar images. At 3 h after injection, the infarct-to-lung ratios were 2.48 +/- 0.27, 1.29 +/- 0.09, and 1.46 +/- 0.04 for acute-infarct rats with (99m)Tc-C2A-GST, sham-operated rats with (99m)Tc-C2A-GST, and acute-infarct rats with 99mTc-C2A-GST-NHS (NHS is N-hydroxy succinimide), respectively. The distribution of radioactivity was confirmed by autoradiography and histology.CONCLUSIONThe C2A domain of synaptotagmin I labeled with fluorochromes or a radioisotope binds to both apoptotic and necrotic cells. Ex vivo and in vivo data indicate that, because of elevated vascular permeability, both specific binding and passive leakage contribute to the accumulation of the radiotracer in the area at risk. However, the latter component alone is insufficient to achieve detectable target-to-background ratios with in vivo planar imaging.

You have accessJournal of UrologyPodium, Wednesday, May 24, 2006, 3:30 - 5:30 pm1 Apr 20061720: Multidetector CT Urography as a Screening Tool for Urinary Tract Neoplasms in Patients with Painless Hematuria Gary Sudakoff, Travis W. Groth, Dell Dunn, William A. See, Daniel Eastwood, Fred Dawson, Robed Heilman, and Peter Langenstroer Gary SudakoffGary Sudakoff More articles by this author , Travis W. GrothTravis W. Groth More articles by this author , Dell DunnDell Dunn More articles by this author , William A. SeeWilliam A. See More articles by this author , Daniel EastwoodDaniel Eastwood More articles by this author , Fred DawsonFred Dawson More articles by this author , Robed HeilmanRobed Heilman More articles by this author , and Peter LangenstroerPeter Langenstroer More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(18)33899-0AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "1720: Multidetector CT Urography as a Screening Tool for Urinary Tract Neoplasms in Patients with Painless Hematuria." The Journal of Urology, 175(4S), pp. 552–553 © 2016 by American Urological AssociationFiguresReferencesRelatedDetails Volume 175Issue 4SApril 2006Page: 552-553 Advertisement Copyright & Permissions© 2016 by American Urological AssociationMetricsAuthor Information Gary Sudakoff More articles by this author Travis W. Groth More articles by this author Dell Dunn More articles by this author William A. See More articles by this author Daniel Eastwood More articles by this author Fred Dawson More articles by this author Robed Heilman More articles by this author Peter Langenstroer More articles by this author Expand All Advertisement Loading ...

(18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is a useful functional imaging method that complements conventional anatomic imaging modalities for screening patients with colorectal hepatic metastases and hepatocellular cancer to determine their suitability for interventional procedures. FDG PET is more sensitive in detecting colorectal cancer than hepatocellular cancer (~90% versus ~50%). The likelihood of detecting hepatic malignancy with FDG PET rapidly diminishes for lesions smaller than 1 cm. The greatest value of FDG PET in these patients is in excluding extrahepatic disease that might lead to early recurrence after interventional therapy. Promising results have been reported with FDG PET that may show residual (local) or recurrent disease before conventional imaging methods in patients receiving interventional therapy. For patients with colorectal hepatic metastases, many investigators believe that patients with PET evidence of recurrent hepatic disease should receive additional treatment even when there is no confirmatory evidence present on other methodologies. For patients with hepatocellular cancer no conclusions regarding the value of FDG PET for assessment of response to interventional therapy can be reached as there is almost no published data.

Background and Study Aims: Scintigraphy is the currently accepted method for evaluation of gastric emptying. Although quantitative, this method is complicated, time-consuming, and costly. If a simple endoscopic technique was available for those instances when quantification of an emptying abnormality is not needed, the same clinical information could be obtained in less time and with resource savings. Our aims in this study were therefore to assess the technical feasibility, tolerability, and safety of unsedated transnasal esophagogastroscopy (T-EG) as a technique for qualitative assessment of gastric emptying. Methods: The study was done in two phases. In the first phase, 18 volunteers (ten men, eight women) underwent T-EG at 4 hours, 5 hours, or 6 hours after ingestion of a standard meal used for scintigraphic evaluation of gastric emptying without radiolabeling. In the second phase, ten volunteers underwent T-EG after scintigraphic imaging had demonstrated complete gastric emptying. Results: Subjects in both phases tolerated the procedure well and completed the study. In the first phase, 13 of 15 volunteers exhibited complete gastric emptying at 6 hours (87 %), while two (13 %) revealed some particulate matter in the stomach at that time. In the second phase, one of the ten volunteers exhibited a small amount of solid food residue in the stomach despite documentation of scintigraphic complete emptying. Conclusions: Evaluation of gastric emptying by unsedated T-EG is both feasible and safe. In healthy, asymptomatic individuals, complete gastric emptying of solid food may take as long as 6 hours.

Thrombus of the renal vein or inferior vena cava is a known complication of renal cell carcinoma (RCC). Accurate discrimination between bland and malignant thrombus can have significant implications toward clinical management. Distinguishing between these 2 entities is not usually possible with enhanced computerized tomography (CT) or magnetic resonance imaging. This case reports the role of combined positron emission tomography-CT imaging in the accurate detection of recurrent RCC after partial nephrectomy and surgically proven tumor thrombus in the renal vein and inferior vena cava.

BACKGROUND:The treatments available for diabetic gastropathy are frequently ineffective. Clinical observations suggest that clonidine, an a-2 adrenergic agonist, may improve diabetic gastropathy symptoms.AIMS:To establish whether a single oral dose of clonidine alters the gastric emptying of a solid meal in 10 patients with diabetic gastropathy and their matched controls. A secondary goal was to compare two methods of analysis of the data from gastric emptying studies.METHODS:Clonidine, 0.3 mg, or a matched placebo were administered orally in a double-blind fashion.RESULTS:Only three of the 10 patients showed an increased gastric residual volume. Gastric emptying rates were comparable in patients and controls. Clonidine had no significant effect on gastric emptying in the controls but increased t1/2 values in the patient group. This effect just reached statistical significance only when calculated by the power exponential method (P=0.05 but not by the linear component model.CONCLUSIONS:Delayed gastric emptying is not an invariable characteristic of symptomatic diabetic gastropathy. Clonidine, given as a single dose of 0.3 mg orally, has no gastric prokinetic effects. It may act on gastric afferent innervation or, more likely, at a central site to reduce nausea and vomiting. The analysis of gastric emptying data by the power exponential and the two linear component methods yields equivalent results.

Single photon emission computerized tomography (SPECT) studies were performed on 34 manifest Huntington's disease (HD) patients at various stages of clinical pathology ranging from early chorea to late dystonia with or without signs of dementia and 12 pre-symptomatic patients with abnormal terminal CAG expansions. Thirty HD patients with obvious clinical signs and seven pre-symptomatic patients without signs or symptoms of HD displayed selective caudate hypoperfusion by direct visual inspection. Such qualitative, selective striatal hypoperfusion patterns can be indicative of early and persistent metabolic changes in striatal neuropathology. SPECT studies can be useful in documenting early pre-clinical changes in patients with abnormal terminal CAG expansions and in confirming the presence of caudate pathology in patients with clinical signs of HD.

Substance P (SP) is an ll-amino acid neuropeptide of the tachykinin family. This study investigated the preparation of an SP analog labeled with 99mTc for imaging SP receptor positive tissue (inflammatory diseases and neoplasms with increased expression of SP receptors). High specific activity 99mTc-SP was prepared using the 1-imino-4-mercaptobutyl (IMB) group as a bifunctional chelator. Biological distribution in mice showed increased 99mTc-SP uptake in the salivary glands (which have a high concentration of SP receptors), but this activity was displaced in animals pre-treated with excess non-radioactive SP. These data show that the uptake of 99mTc-SP is receptor specific. IMB derivatization at the N-terminal location is suitable for labeling of SP analogues with 99mTc. Synthetic analogues of SP labeled with 99mTc may be an attractive alternative to 111In labeled molecules and merit further investigation.

The diagnostic efficacy of (1) combined three-phase bone scintigraphy and In-111 labeled WBC scintigraphy (Bone/WBC), (2) MRI, and (3) conventional radiography in detecting osteomyelitis of the neuropathic foot was compared. Conventional radiography was comparable to MRI for detection of osteomyelitis. MRI best depicted the presence of osteomyelitis in the forefoot. Particularly in the setting of Charcot joints, Bone/WBC was more specific than conventional radiography or MRI.