An Uncommon Variant of an Uncommon Disease: A Caucasian Adolescent with Apical Hypertrophic Cardiomyopathy Diagnosed with Myocardial Perfusion Imaging.

Apical hypertrophic cardiomyopathy (ApHCM) is a subtype of HCM. This variant is more common in the Asian population when compared to North American patients. Patients may present with arrhythmias, heart failure, myocardial infarction, chest discomfort, fatigue, and presyncope or syncope. Initial evaluation requires electrocardiogram and two-dimensional echocardiogram. T-wave inversion in the precordial leads as well as hypertrophy of the left ventricle is hallmarks of the disease. Cardiac magnetic resonance (CMR) imaging is the most specific and sensitive imaging modality. In patients with contraindications for CMR, myocardial perfusion imaging (MPI) has been described to have diagnostic characteristics for ApHCM. MPI images demonstrating a "solar polar" map pattern and increased apical tracer uptake in single-photon emission computed tomography horizontally and vertical long-axis slices are consistent with the diagnosis of ApHCM. Herein, we present a case of a Caucasian adolescent female who underwent a cardiac screening to rule out hypertrophic obstructive cardiomyopathy. Initially, the patient was unable to undergo CMR, and an MPI was utilized to assist with the diagnosis of ApHCM.

Mediastinal Masses in Nuclear Medicine Studies: A Diagnostic Algorithm.

There are multiple reasons for an anterior mediastinal mass. In this case, we discuss possible etiologies and offer an algorithm to narrow the differential diagnosis. When the mass cannot be diagnosed radiographically, the next step in imaging is a physiologic assessment with radionuclide modalities.

Optimizing 18F-FDG Uptake Time Before Imaging Improves the Accuracy of PET/CT in Liver Lesions.

UNLABELLED: (18)F-FDG PET/CT has emerged as one of the fastest-growing imaging modalities. A shorter protocol results in a lower target-to-background ratio, which can increase the challenge of identifying mildly (18)F-FDG-avid lesions and differentiating inflammatory or physiologic activity from malignant activity. The purpose of this study was to determine the delay between radiotracer injection and imaging that optimizes target-to-background ratio while maintaining counts high enough to ensure scan sensitivity. METHODS: The study included 140 patients (66 male and 74 female; age range, 42-95 y) with suspected hepatic lesions as seen on an (18)F-FDG PET scan. SUV was determined as region-of-interest activity/(dose/total body weight). RESULTS: The mean injected dose was 610 ± 66.6 MBq (16.5 ±1.8 mCi), with a mean glucose level of 107 ± 26.6 mg/dL (standardized to 90 mg/dL). The uptake time before imaging ranged from 61 to 158 min, with a mean of 108.8 ± 24.8 min. The P values for the correlation of SUV to time were 0.004, 0.003, and 0.0001 for malignant lesions, benign lesions, and background hepatic tissue, respectively. CONCLUSION: An approximately 90-min time window from (18)F-FDG injection to PET imaging would significantly improve target-to-background ratio and, thus, quantitation and visual interpretation. This benefit outweighs the minimal loss in patient throughput.

The Evaluation of Lupus Myocarditis with 13N-Ammonia and 18F-FDG PET.

Although the use of (13)N-ammonia and (18)F-FDG PET shows great promise as a tool for diagnosing heart involvement in inflammatory diseases, it can be equally powerful for following disease progression and treatment outcome. We describe a case in which (18)F-FDG PET was effective in following up the treatment outcome of lupus myocarditis.

Appearance of Meningioma on 99mTc-HMPAO SPECT: Correlation with MRI.

On brain perfusion SPECT, a primary brain lesion presents as a localized defect that corresponds to the mass lesion. (99m)Tc-HMPAO images generally show a focal defect in the region of abnormality, whether containing necrotic tissue, recurrent tumor, or both. Further characterization with MR imaging is needed to confirm the diagnosis, as demonstrated in this case report.

The Evaluation of Cardiac Sarcoidosis with 18F-FDG PET.

Cardiac involvement in sarcoidosis is associated with poor prognosis. (18)F-FDG PET can detect the presence of cardiac sarcoidosis, assess disease activity, and serve as a means to monitor treatment response in patients with cardiac sarcoidosis.

Evaluation of a Case of Inflammatory Breast Cancer with 18F-FDG PET/CT.

Inflammatory breast cancer is a rare and aggressive form of cancer characterized by dermal lymphatic invasion and tumor embolization resulting in erythema and edema. In many cases, by the time of diagnosis there is already distant metastasis. Mammography, sonography, CT, and MRI are usually performed for initial staging; however, PET/CT can also be used for initial staging as it offers additional diagnostic information.

Systemic mastocytosis: a rare cause of single vertebral body uptake on bone scan.

Systemic Mastocytosis is a rare condition characterized by the abnormal proliferation of Mast Cells. Presentation as a solitary vertebral body lesion is extremely uncommon and may be confused with more ominous conditions such as metastasis. Familiarity with the condition can heighten clinical suspicion, direct tissue diagnosis, guide management and indicate appropriate follow up. We present a case of a 64-year-old woman undergoing staging for recently diagnosed breast cancer who was found to have Systemic Mastocytosis of a single vertebral body.

Hepatobiliary Iminodiacetic Acid Scanning Detects High-Grade Biliary Obstruction Secondary to IgG4-Related Sclerosing Cholangitis.

In this report, we present a case of high-grade biliary obstruction discovered on hepatobiliary scintigraphy secondary to IgG4-related sclerosing cholangitis with concomitant autoimmune pancreatitis, a recently described entity that is gaining recognition in the radiology literature. To our knowledge, the scintigraphic findings have yet to be described in the literature. We present the hepatobiliary scintigraphic findings and their correlation to findings on endoscopic retrograde cholangiopancreatography, CT, and MR cholangiopancreatography, with posttreatment follow-up imaging. IgG4-related sclerosing cholangitis is a rare yet important diagnostic consideration when high-grade obstruction is seen on hepatobiliary iminodiacetic acid scanning. We discuss the differential diagnosis of high-grade biliary obstruction seen on hepatobiliary iminodiacetic acid scanning.

Lumbosacral Transitional Vertebra Diagnosed on 99mTc-Methylene Diphosphonate SPECT/CT.

Lumbosacral transitional vertebra (LSTV) is a congenital anomaly of the lumbosacral junction. The association between back pain and LSTV is controversial; however, in our patient the symptoms localized to a hemisacralized left transverse process of L5. LSTV should be included in the differential diagnosis in young patients with lower back pain, and scintigraphic imaging should be considered for diagnostic purposes.

Use of SPECT/CT with 99mTc-MDP Bone Scintigraphy to Diagnose Symptomatic Os Acromiale.

Os acromiale is an anatomic variant that in rare cases can cause pain. (99m)Tc-methylene diphosphonate bone scintigraphy with SPECT/CT can play an important role in diagnosing this clinical entity. We present a male football player with shoulder pain secondary to a symptomatic os acromiale, and we demonstrate the findings on bone scanning with limited SPECT/CT that diagnosed this important clinical abnormality.

The Appearance of Maffucci Syndrome on 18F-FDG PET/CT.

Maffucci syndrome is a rare condition with multiple enchondromas and hemangiomas. Fewer than 200 cases have been reported in the United States. There is a high predilection for neoplastic changes, and PET/CT has an important role in detecting these changes.

Liver uptake on bone scanning: a diagnostic algorithm.

In this report, we present a case of liver uptake seen on a bone scan that was due to diffuse metastatic disease from breast carcinoma. We discuss possible etiologies for the uptake and offer an algorithm to narrow the differential diagnosis.

The appearance of congenitally corrected transposition of the great arteries on myocardial perfusion imaging.

We present a case of incidentally discovered congenitally corrected transposition of the great arteries (ccTGA), initially seen on stress-rest myocardial perfusion imaging (MPI). ccTGA has a characteristic appearance on MPI, which reflects the functional alterations associated with this condition.

Detection of Aberrant Right Subclavian Artery by PET/CT.

An aberrant right subclavian artery can be diagnosed by PET/CT, as demonstrated in this case of a 70-y-old man undergoing PET/CT for staging of squamous cell carcinoma of the right lung. It is important to report this finding during the evaluation of oncologic patients, to prevent severe complications that may arise from various oncologic interventions.

18F-FDG PET assessment of Lewy body dementia with cerebellar diaschisis.

Alzheimer disease and Lewy body dementia are the 2 most common causes of dementia. Each disease has distinctive regional metabolic reduction patterns on (18)F-FDG PET. In this report, we present a rare case of an elderly man with dementia whereby (18)F-FDG PET clearly showed Lewy body disease with crossed cerebellar diaschisis.

The use of 99mTc-MDP bone scanning to assess facial bone growth.

Bone scanning is an important technique to detect mandibular growth, and its quantitation aids in deciding the optimal timing for surgery. Here, we will discuss a case of abnormal mandibular growth and use of bone scanning to evaluate the facial bone growth.

Time sensitivity-corrected retention index: an enhanced metabolic index from 18F-FDG PET to differentiate between benign and malignant pulmonary nodules.

The aim of the study was to evaluate pulmonary nodules (PNs) by incorporating time sensitivity (S) factor in the retention index (RI) and compare with the traditional fixed interval method. After obtaining approval from the Human Investigations Committee, 97 PNs from 81 patients (age=70±11) referred for dual-time fluorine-18 fluorodeoxyglucose PET (16.1±1.9 mCi) with definite pathological diagnosis or 1-year computed tomography follow-up were retrospectively studied. S=d{ln[SUV]]/d{ln[T]} was obtained by logarithmic regression using scan times, T (0, 1, 2), and standard uptake value (SUV) (0, 1, 2). This time-corrected RI, RIs=[(T2/T1)-1]×100%, was compared with traditional fixed time interval RI, RIx=[(SUV2/SUV1)-1]×100%, by means of receiver operating characteristic curve analysis. The mean±SD of T1 and T2 (72.3±14.0 and 134.9±17.6 min, respectively) skewed markedly from the intended time of PET scans (skewness=2.076 and 1.356, respectively). There were 27 benign tumors, 37 cases of non-small-cell lung cancer, 15 other types of cancer, and 18 stable lesions by 1-year computed tomography follow-up. There were significant differences between the nonmalignant group (NM, n=45) and the cancer group (CA, n=52) in time sensitivity (0.186±0.161 vs. 0.483±0.180, P<0.0005) and RIs (12.7±12.5 vs. 37.4±17.5%, P<0.0005). The RIx showed wider variation than RIs, although the difference between NM and CA was also significant (18.0±28.8 vs. 37.8±32.0%, P=0.002). The RIs and RIx were only weakly correlated (r=0.257, P=0.011). Receiver operating characteristic curve analysis performed for the CA or NM groups revealed a significant improvement in the diagnostic accuracy for malignancy by RIs (area under the curve=0.880±0.035, P<0.0005) compared with RIx (area under the curve=0.694±0.054, P=0.001). Incorporating the time sensitivity factor improves the diagnostic performance of RI for malignant PNs by using additional biologic information from the variation in fluorine-18 fluorodeoxyglucose uptake times and rates.

Use of SPECT/CT with 99mTc-MDP bone scintigraphy to diagnose sacral insufficiency fracture.

Bone SPECT/CT offers additional information on pelvic insufficiency fractures, especially when there is incomplete formation of the H-sign on planar bone scanning.