Incidental diagnosis of presacral ganglioneuroma in a patient with hematuria.

Ganglioneuromas are benign neuroblastic tumors seen most in pediatric population. The most common locations are mediastinal, retroperitoneal and adrenal regions. Ganglioneuromas rarely occur in presacral space. We present one such case of an incidentally diagnosed presacral ganglioneuroma in an asymptomatic 71-year-old male who initially presented with hematuria.

Primary pulmonary artery sarcoma versus pulmonary thromboembolism: a multimodal imaging comparison.

Primary pulmonary artery sarcoma (PPAS) is a rare malignancy that is commonly mistaken for pulmonary embolism due to similarities in clinical presentation and radiographic findings. Distinct radiographic findings to help differentiate between the two diseases are highlighted in the case presented. (1) Several nuances in various imaging modalities have been identified to help distinguish pulmonary artery sarcoma from pulmonary thromboembolic disease. (2) The wall eclipsing sign is considered pathognomonic for pulmonary artery sarcoma. (3) Positron emission tomography/computed tomography may help reduce time between diagnosis and treatment, which may ultimately prolong survival. (4) Providers should be well versed on the subtle differences on imaging to prevent future delays in diagnosis and treatment.

Imaging Cobalamin Uptake within Malignant Breast Tumors In Vivo.

PURPOSE: To image the uptake of cobalamin (Cbl) within malignant breast tumors in vivo. PROCEDURES: Prior to surgery 20 female patients with clinically suspected breast tumors were intravenously administered 0.25 µg of an In-111 labeled 5-deoxyadenosylcobalamin (AC) analog ([111In]AC) and sequentially imaged with whole-body planar (WBP) and single-photon emission computed tomography (SPECT) between 2-5 h and 20-24 h post-injection (P.I.). The tumor to background (T/B) ratio for [111In]AC in breast tumors at 2-5 h was correlated to its expression of estrogen (ER), progesterone (PR), and human epidermal growth factor 2 (HER2) receptors. Subsequent pulse chase (PC) experiments in nude mice burdened with the MDA-MB-231 triple-negative (TN) breast tumor xenograft measured the effect that pulses of AC or dexamethasone (DEX) had on [111In]AC uptake in both normal murine tissue and the TN breast tumor. RESULTS: The mean [111In]AC T/B ratio of the patients' 18 resected tumors was 5.8. Comparing ER- and PR-positive tumors (n = 11) to TN and HER2-positive tumors (n = 7), the mean [111In]AC T/B ratios at 2-5 h P.I. were 3.2 (range 1.8-5.6) and 10.4 (range 3.3-22.5), respectively. Pulses of 2.0 µg of AC at 2, 8, or 24 h; or 40.0 µg of DEX at 24 h prior to injecting 0.5 µg of [111In]AC, increased mean tracer uptake in the MDA-MB-231 tumors by 26.4, 71.5, 92.6, and 49.1 %, respectively. Only the 2- and 24-h PC intervals concomitantly suppressed [111In]AC uptake in normal murine tissue while enhancing [111In]AC uptake in MDA-MB-231 tumors. CONCLUSION: The uptake of Cbl within malignant breast tumors can be imaged clinically. Cbl uptake is greatest in TN and HER2-positive breast tumors. A solitary bolus of AC or DEX increases the [111In]AC uptake within a breast tumor in vivo. Investigating the cytogenetic mechanisms controlling the endocytosis of Cbl in malignant breast tumors is warranted.

Prospective assessment of dynamic CT and MR cholangiography in functional biliary pain.

OBJECTIVE: The objectives of our study were to assess the feasibility of dynamic CT and MR cholangiography during gallbladder stimulation, to compare CT and MR cholangiography with biliary scintigraphy, and to identify morphologic differences between patients with functional biliary pain and healthy control subjects. SUBJECTS AND METHODS: In this prospective study, 30 patients with functional biliary pain underwent biliary scintigraphy, CT cholangiography, and MR cholangiography before and during 45-minute sincalide infusions. Thirty healthy control subjects also underwent MR cholangiography with sincalide infusion. IV contrast agents (iodipamide meglumine or gadobenate dimeglumine) were administered before scanning. CT and MR images were qualitatively and quantitatively analyzed. RESULTS: Diagnostic images were obtained of all participants. There was good agreement for gallbladder ejection fraction (EF) at 40 minutes by all three methods (Lin's concordance correlation coefficient ≥ 0.6). Gallbladder contraction and refilling occurred more promptly by CT and MR cholangiography than scintigraphy. CT and MR cholangiography showed previously undiagnosed gallstones in two patients (7%). Gallbladder shape was categorized as straight, curved, or folded; a folded gallbladder was present in 37% and 23% of patients at baseline and 40 minutes, respectively, versus in 3% of control subjects at both times (p ≤ 0.004). Asymmetric patterns of gallbladder contraction occurred in 10 patients (33%) and four control subjects (13%) (p = 0.13). CONCLUSION: Dynamic CT cholangiography and MR cholangiography performed during pharmacologic stimulation accurately measure gallbladder EFs and detect missed gallstones. Gallbladder shape before and during contraction differs between patients with functional biliary pain and healthy control subjects. Dynamic CT cholangiography and MR cholangiography are promising techniques that might improve selection of patients to undergo cholecystectomy for functional biliary pain.

Evaluation of molecular breast imaging in women undergoing myocardial perfusion imaging with Tc-99m sestamibi.

BACKGROUND: Our objective was to explore the potential benefits of molecular breast imaging (MBI) as a screening technique in women undergoing stress myocardial perfusion studies. METHODS: MBI was offered to women receiving Tc-99m sestamibi injection for myocardial perfusion stress testing. During the required waiting period after stress isotope injection, MBI was performed using a dedicated breast imaging gamma camera system. MBI examinations were interpreted by breast radiologists, with review of a recent mammogram in cases with positive MBI. RESULTS: Of 322 women enrolled, 313 completed MBI, comprising 5 with known breast cancer, 2 with known high-risk benign breast lesions, and 306 who were asymptomatic for breast disease with a recent negative mammogram. Analysis was limited to the 306 patients with no known breast disease. MBI was positive in 22 of 306, giving a recall rate of 7.2% (95% confidence interval [CI] 4.8-10.6]. MBI detected 4 new cancers, resulting in a supplemental diagnostic yield of 13.1/1000 women screened (95% CI 5.1-33.2). The number of cancers diagnosed per abnormal MBI examinations (PPV(1)) was 18% (4 of 22) (95% CI 7.3-38.5), and the number diagnosed per MBI-prompted biopsies (PPV(3)) was 44% (4 of 9) (95% CI 18.9-73.3). CONCLUSIONS: The addition of MBI to clinically indicated stress myocardial perfusion imaging studies in women results in a high diagnostic yield of newly detected breast cancers while generating a low rate of additional unnecessary workup.

The value of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography in extranodal natural killer/T-cell lymphoma.

PURPOSE: To our knowledge, there are no published data pertinent to the use of [(18F)]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in patients with natural killer (NK)/T-cell lymphoma. The purpose of this study was to assess the value of FDG PET/CT in this aggressive type of non-Hodgkin lymphoma. PATIENTS AND METHODS: All patients with NK/T-cell lymphoma referred for FDG PET/CT at our institution from July 2001 to July 2006 were retrospectively studied. PET/CT examinations were blindly reviewed by 2 experienced readers. The results were compared with the status of the disease, which was determined after evaluation of biopsy, laboratory, clinical and conventional imaging examination, and follow-up results. PET/CT results were thereby classified as true-positive, true-negative, false-positive, or false-negative. The degree of FDG uptake in the positive lesions was semiquantified using maximum standard uptake value (SUV(max)). RESULTS: Twenty-one PET/CT examinations were performed in 10 patients with NK/T-cell lymphoma. For nasal disease, PET/CT was true-positive in 5 cases, true-negative in 15 cases, and positive but unconfirmed in 1 case. For extranasal disease, PET/CT was true-positive in 3 cases, true-negative in 16 cases, and false-negative in 2 cases. The mean SUV(max) in PET-positive lesions in nasal cavities or paranasal sinuses was 16 gm/mL (range, 5-25 gm/mL; median, 19.3 gm/mL). In extranasal disease, the mean SUV(max) was 10.9 gm/mL (range, 4.6-34.1 gm/mL; median, 5.6 gm/mL). CONCLUSION: Viable NK/T-cell lymphoma is intensely FDG hypermetabolic. PET/CT appears to be sensitive for the detection of disease in the nasopharynx and, to a lesser extent, in extranasal sites.

Hibernoma: 18F FDG PET/CT imaging.

The patient was a 40-year-old woman who was diagnosed with a malignant melanoma of the left posterior thigh. Follow-up positron emission tomography (PET)/computed tomography (CT) examination revealed an intensely FDG-avid lesion that predominantly contained fat in the right postero-lateral chest wall involving the latissimus dorsi. Ultrasound-guided fine needle aspirate and core biopsy confirmed the diagnosis of hibernoma rather than melanoma metastasis.

The value of quantifying 18F-FDG uptake in thyroid nodules found incidentally on whole-body PET-CT.

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.

Molecular breast imaging: advantages and limitations of a scintimammographic technique in patients with small breast tumors.

Preliminary studies from our laboratory showed that molecular breast imaging (MBI) can reliably detect tumors <2 cm in diameter. This study extends our work to a larger patient population and examines the technical factors that influence the ability of MBI to detect small breast tumors. Following injection of 740 MBq Tc-99m sestamibi, MBI was performed on 100 patients scheduled for biopsy of a lesion suspicious for malignancy that measured <2 cm on mammography or sonography. Using a small field of view gamma camera, patients were imaged in the standard mammographic views using light pain-free compression. Subjective discomfort, breast thickness, the amount of breast tissue in the detector field of view, and breast counts per unit area were measured and recorded. Follow-up was obtained in 99 patients; 53 patients had 67 malignant tumors confirmed at surgery. Of these, 57 of 67 were detected by MBI (sensitivity 85%). Sensitivity was 29%, 86%, and 97% for tumors <5, 6-10, and > or =11 mm in diameter, respectively. In seven patients, MBI identified eight additional mammographically occult tumors. Of 47 patients with no evidence of cancer at biopsy or surgery, there were 36 true negative and 11 false positive scans on MBI. MBI has potential for the regular detection of malignant breast tumors less than 2 cm in diameter. Work in progress to optimize the imaging parameters and technique may further improve sensitivity and specificity.

Comparison of small field of view gamma camera systems for scintimammography.

OBJECTIVE: To compare the performance characteristics of three compact gamma camera systems for scintimammography. METHODS: A multi-crystal NaI system (Dilon 6800), a multicrystal CsI system (Digirad 2020tc Imager) and a prototype cadmium zinc telluride (CZT) detector were evaluated using a breast phantom with simulated tumours of 1.8-9.8 mm in diameter and a tumour to background ratio of 5.6 : 1. A conventional Anger-based gamma camera was also evaluated for comparative purposes. RESULTS: The conventional gamma camera had the highest intrinsic sensitivity of the four systems and utilized the highest resolution collimator. However, the prototype CZT and the CsI systems yielded the best spatial resolution over the range 0-5 cm from the collimator face and better visualized small (5-7 mm) tumours. CONCLUSION: In addition to the advantage of close proximity to the breast, two of the three compact detectors offered superior performance to a conventional gamma camera for scintimammography.

Molecular breast imaging: a new technique using technetium Tc 99m scintimammography to detect small tumors of the breast.

OBJECTIVE: To determine the sensitivity of molecular breast imaging (MBI) to detect small cancers of the breast. PATIENTS AND METHODS: A cadmium-zinc-telluride gamma camera with a field of view of 20 x 20 cm was used. The detector elements were 2.5 x 2.5 mm. The gamma camera was mounted on a modified mammographic gantry. Between November 2001 and March 2004, we performed MBI on patients who were scheduled to undergo biopsy for a lesion suggestive of malignancy that was smaller than 2 cm on a mammogram. Patients were injected with 20 mCi of technetium Tc 99m sestamibi and underwent imaging immediately after injection. Using light pain-free compression, we obtained craniocaudal and mediolateral oblique views of each breast. RESULTS: Of the 40 women included in the study, 26 had a total of 36 malignant lesions confirmed at surgery. Of these 36 lesions, 33 were detected by MBI (overall sensitivity, 92%). Of the 22 malignant lesions 1 cm or smaller in diameter, 19 were detected by MBI (sensitivity, 86%). Two patients had false-negative MBI results. Of the 14 malignant lesions larger than 1 cm in diameter, all were identified correctly by MBI. In 4 patients, MBI identified additional lesions not seen on mammography that were confirmed subsequently on magnetic resonance imaging and were true-positive cases at surgery. Three of these patients had lesions in the breast contralateral to the breast containing the initial mammographic finding suggestive of malignancy. Of 14 patients with no evidence of cancer at biopsy or surgery, 9 had true-negative (normal) scans and 5 had false-positive scans on MBI. False-positive results included benign fibroadenoma (2 patients), inflammatory fat necrosis (1 patient), benign breast parenchyma (1 patient), and complex sclerosing lesion (1 patient). CONCLUSION: This prototype gamma camera system for MBI reliably detects malignant breast lesions smaller than 2 cm. Furthermore, we obtained the highest sensitivity (86%) yet reported for the detection of lesions smaller than 1 cm. These results suggest an important role for MBI, particularly for women in whom the sensitivity of mammography is reduced by the density of the breast parenchyma.

Evaluation of a small cadmium zinc telluride detector for scintimammography.

UNLABELLED: The purpose of this study was to evaluate a small semiconductor-based gamma camera that may have applications in scintimammography. METHODS: A small cadmium zinc telluride (CZT) detector was evaluated. The detector had a field of view of 20 x 20 cm with detector elements of 2.5 x 2.5 mm in size. Both short-bore (35 mm) and long-bore (50 mm) collimators, matched to the geometry of the detector elements, were evaluated. The imaging performance of the CZT detector was compared with that of a conventional gamma camera equipped with all-purpose and ultra-high-resolution collimators. The performance of both systems with respect to breast imaging was evaluated using a water tank containing small glass spheres, 1.8-9.8 mm in diameter. The effects of variations in breast thickness, tumor depth, and tumor-to-background ratio were all simulated in this phantom model. Total counts per image were adjusted to approximate the count density observed in clinical scintimammographic studies. RESULTS: Sensitivity of the CZT detector was 76% that of the equivalent NaI system. The system demonstrated excellent integral uniformity. The energy resolution of the CZT system was 6.5% for (99m)Tc. Spatial resolution with the long-bore collimator was superior to that of a conventional large field-of -view gamma camera equipped with an ultra-high- resolution collimator, over the range 0-6 cm from the collimator face. A blinded review of breast phantom images showed that small spheres (< or =7 mm in diameter) were better seen and had a better tumor-to-background ratio with the CZT system than with the conventional gamma camera. CONCLUSION: A small CZT detector offers superior performance to a conventional gamma camera and should permit reliable detection of breast tumors <1 cm in size.