Head and Neck Cancer Soft Tissue Radiation Necrosis-Diagnostic Challenge.

A 53-year-old man with T4aN2cM0 tongue base squamous cell carcinoma received definitive chemoradiation. FDG PET/CT at 6 weeks showed partial metabolic response with soft tissue air indicating radiation necrosis at primary site and complete response in the neck. At 9 weeks, contrasted CT showed worsening but nonenhancing ulceration, area biopsied demonstrating a minute carcinoma focus with treatment effect. At 12 weeks, PET/CT showed increased primary site uptake interpreted as disease progression; however, no viable tumor was found at salvage surgery. Because nonenhancing ulceration predicts pure radiation necrosis with no viable tumor, contrasted CT may guide treatment selection in challenging cases.

Hepatic Hemangioma on SPECT Myocardial Perfusion Imaging.

Extracardiac uptake on SPECT MPI, seen with physiologic radiotracer distribution, benign or malignant neoplasm, infection, inflammation, or granulomatous disease, may confound the accuracy of MPI or lead to unsuspected pathology. A 38-year-old woman with end-stage renal disease on hemodialysis had SPECT MPI for renal transplant preoperative risk stratification, showing left anterior descending artery ischemia and an intense extracardiac soft tissue focus adjacent to the diaphragmatic right ventricle concerning for focal infection related to prior coronary or gastric surgeries or tumor. CT revealed focal herniation of liver containing a flash-fill hemangioma into the left hemithorax accounting for this focal uptake.

ACR-ACNM Practice Parameter for the Performance of Dopamine Transporter (DaT) Single Photon Emission Computed Tomography (SPECT) Imaging for Movement Disorders.

This American College of Radiology and American College of Nuclear Medicine joint clinical practice parameter is for performance of dopamine transporter single photon emission computed tomography (SPECT) imaging, for patients with movement disorders. Parkinsonian syndrome (PS) consists of a group of neurodegenerative diseases including Parkinson disease (PD), progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal degeneration (CBD), and dementia with Lewy bodies (DLB). Accurate diagnosis of PS is critical for clinical management. An important diagnostic dilemma is the differentiation of PS and non-neurodegenerative disorders, such as essential tremor (ET) or drug-induced tremor, due to the overlap of clinical symptoms. The management approach to these conditions is distinctly different. An abnormal iodine-123 ioflupane SPECT scan suggests a decreased amount of dopamine transporter in the striatum, that is, a diagnosis of nigrostriatal neurodegenerative PS, whereas a normal scan suggests ET or other nondegenerative parkinsonism (drug-induced, vascular, or psychogenic).

Nuclear Protein in Testis Midline Carcinoma Presenting in an Infant as a Pericardial Mass with Staging by 18F-Fluorodeoxyglucose-positron Emission Tomography/Computed Tomography.

Nuclear protein in testis (NUT) midline carcinoma (NMC) is a rare, aggressive, lethal, epithelioid, poorly differentiated cancer first described in Japan in 1991, unique in that is defined genetically rather than by histological tissue of origin. It usually arises in the body midline and presents as a mass with metastasis. An infant presenting with pneumonia was found to have a pericardial mass, NMC resected, and subsequent staging positron emission tomography (PET) showing residual mediastinal tumor and midline abdominal metastases. Fewer than 100 cases of NMC have been reported in the literature, and PET appears to be the imaging modality of choice in complete staging and evaluation of treatment response.

BK Nephritis and Venous Thrombosis in Renal Transplant Recipient Detected by 111In Leukocyte Imaging.

Three months after deceased donor kidney transplant, a patient who presented with proteinuric renal dysfunction and fever of undetermined origin was found to have BK viruria by quantitative polymerase chain reaction analysis. An ¹¹¹In leukocyte scan showed increased renal transplant uptake consistent with nephritis and linear uptake in the knee. Venous duplex ultrasound revealed acute occlusive thrombosis in the superficial right lesser saphenous vein in the area of increased radiolabeled leukocyte uptake. This ¹¹¹In leukocyte scan performed for fever of undetermined origin demonstrated findings of BK nephritis in a renal transplant patient and associated acute venous thrombosis related to leukocyte colonization.

FDG PET/CT in evaluation of unusual cutaneous manifestations of breast cancer.

Cutaneous metastases of primary internal malignancies are rare, with an incidence of 0.7% to 10.4%. Cutaneous manifestations due to breast cancer are the most common metastases dermatologists observe, with a prevalence of 2.4% and an incidence of 23.9%. Presence of cutaneous metastases is usually a late event in disease progression, indicating grave prognosis. Recognition of cutaneous breast cancer metastases significantly alters therapeutic plans, especially when the disease was thought to be successfully cured. F-FDG PET CT imaging can detect cutaneous metastasis and sites of distant metastases and monitor response to therapy. We report 3 patients with cutaneous-predominant breast carcinoma seen by FDG PET/CT.

Presurgical lateralization of seizure focus in temporal lobe epilepsy with noninvasive imaging.

We retrospectively compared the seizure focus-localizing capability of interictal PET/CT to that of interictal magnetic resonance diffusion-weighted imaging and ictal SPECT in 21 patient candidate for neurosurgery with temporal lobe epilepsy (TLE) by assessing overall lateralizing ability of these modalities and concordance of findings on these studies with results of electroencephalography (EEG). PET/CT demonstrated the greatest lateralizing ability of any of the imaging modalities and had the highest concordance rate for lateralization with EEG, highlighting its increasing diagnostic utility in the preoperative imaging workup of patients with medically intractable TLE.

Imaging of gastrointestinal bleeding.

Radiological techniques are important in evaluating patients with gastrointestinal bleeding. Scintigraphic, computed tomographic angiographic, and enterographic techniques are sensitive tools in identifying the source of bleeding and may be useful in identifying patients likely to have a benign course and in selecting patients for therapeutic intervention. Angiography plays a key role in bleeding localization, and modern embolization techniques make this a viable therapeutic option. With the refining developments in body imaging and related reconstructive techniques, it is likely that radiological interventions will play an expanding and critical role in evaluating patients with gastrointestinal hemorrhage in the future.

The predictive value of incidental PET/CT findings suspicious for breast cancer in women with non-breast malignancies.

BACKGROUND: On occasion, patients followed with positron emission tomographic (PET)/computed tomographic (CT) imaging for nonbreast malignancies will have incidental breast findings concerning for second primary breast cancers. The aim of this study was to determine the predictive value of PET/CT imaging to identify breast cancers in these patients. METHODS: Patients with primary nonbreast malignancies and findings concerning for second primary breast cancers were identified from a prospectively acquired nuclear medicine database from January 2005 to July 2008. Chart reviews were then performed. RESULTS: Nine hundred two women underwent PET/CT imaging to evaluate nonbreast malignancies. Nine women (1%) had concerning breast findings, and 5 (56%) had subsequent breast cancer diagnoses. The positive predictive value of PET/CT imaging in these patients was 63%. Evidence of compliance with current screening guidelines was present in only 22% of these patients. CONCLUSIONS: The data suggest that findings concerning for an additional primary breast cancer should be evaluated and that age-appropriate screening tools should not be abandoned.

Incidental PET/CT findings in the cancer patient: how should they be managed?

BACKGROUND: Despite a paucity of evidence-based guidelines, the use of PET/CT (positron emission tomography/computed tomography) in the management of cancer patients is increasing. As widespread clinical application increases, unexpected radiographic findings are occasionally identified. These incidental findings are often suspicious for a second primary malignancy. The purpose of this study was to determine the clinical impact of these incidental PET/CT findings. METHODS: A query of our prospectively acquired Nuclear Medicine database was performed to identify patients with a known malignancy being staged or serially imaged with PET/CT. Patients with incidental findings suggestive of a second primary malignancy were selected. Statistical analysis was performed to determine the ability of PET/CT to identify a second primary malignancy. All PET/CT were interpreted by board certified nuclear radiologists. RESULTS: Of 3,814 PET/CT scans performed on 2,219 cancer patients at our institution from January 1, 2005, to December 29, 2008, 272 patients (12% of all patients) had findings concerning for a second primary malignancy. An invasive work-up was performed on 49% (133/272) of these patients, while 15% (40/272) had no further evaluation due to an advanced primary malignancy. The remaining 36% (99/272) had no further evaluation secondary to a low clinical suspicion determined by the treating team, a clinical plan of observation, or patients lost to follow-up. Of the 133 patients evaluated further, clinicians identified a second primary malignancy in 41 patients (31%), benign disease in 62 patients (47%), and metastatic disease from their known malignancy in 30 patients (23%). The most common sites for a proven second primary malignancy were: lung (N = 10), breast (N = 7), and colon (N = 5). Investigation of these lesions was performed using several techniques, including 24 endoscopies (6 malignant). A surgical procedure was performed in 74 patients (29 malignant), and a percutaneous biopsy was performed on 34 patients (12 malignant). The overall positive predictive value for PET/CT to detect a second primary malignancy was 31% in this subgroup. At a median follow-up of 22 months, 9 of 41 patients with a second primary were dead of a malignancy, 20 were alive with disease, and 12 had no evidence of disease. CONCLUSION: Incidental PET/CT findings consistent with a second primary are occasionally encountered in cancer patients. In our data, approximately half of these findings were benign, a third were consistent with a second primary malignancy or a metastatic focus, and the remainder were never evaluated due to physician and patient decision. Advanced primary tumors are unlikely to be impacted by a second primary tumor suggesting that this subset of patients will not benefit from further investigation. Our data suggests that, despite the high rate of false positivity, incidental PET/CT findings should be investigated when the results will impact treatment algorithms. The timing and route of investigation should be dictated by clinical judgment and the status of the primary tumor. Further investigation will need to be performed to determine the long-term clinical impact of incidentally identified second primary malignancies.

Revisiting the role of positron-emission tomography/computed tomography in determining the need for planned neck dissection following chemoradiation for advanced head and neck cancer.

OBJECTIVES/HYPOTHESIS: Planned neck dissection following chemoradiation (CR) has been advocated in patients with head and neck squamous cell cancer (HNSCC) with advanced nodal disease and a clinical complete response to CR because of the potential for residual occult nodal disease. The utility of positron-emission tomography/computed tomography (PET-CT) in identifying occult nodal disease in this scenario is controversial. METHODS: The medical records of all patients treated with CR for advanced HNSCC with N2 or N3 disease from December 2003 to June 2007 were reviewed. Patients with a complete clinical response were included if PET-CT performed 8 to 11 weeks after CR showed no distant disease and they underwent planned neck dissection. RESULTS: Thirty-two patients met study criteria. PET-CT was positive for residual nodal disease in 20 patients (63%). Pathology revealed carcinoma in 10 patients (31%): six of 20 patients with positive PET-CT scans (30%) and four of 12 patients with negative PET-CT scans (33%). The sensitivity and specificity of PET-CT was 60% and 36%. Regional recurrence developed in two patients (6%) who were not successfully salvaged. CONCLUSIONS: PET-CT performed 8 to 11 weeks after CR does not reliably predict the need for planned post-treatment neck dissection in patients with a complete clinical response following CR. Regional recurrence rates are comparable to those reported for patients observed with PET-CT, suggesting no advantage for planned neck dissection, and salvage rates were poor. These data suggest that delaying the timing of PET-CT, with surgery reserved for positive findings, is a reasonable alternative to planned neck dissection to avoid unnecessary surgery.

Identification of distant metastases with PET-CT in patients with suspected recurrent head and neck cancer.

OBJECTIVES: To investigate the utility of positron-emission tomography/computed tomography (PET-CT) in identifying distant metastatic disease in patients with suspected recurrent head and neck squamous cell cancer (HNSCC). STUDY DESIGN: Retrospective analysis. METHODS: Retrospective analysis of 64 consecutive patients with suspected recurrent HNSCC following definitive treatment who underwent PET-CT imaging were eligible for inclusion. Patients with previous known distant metastatic disease were excluded. RESULTS: The majority of patients (81%) had TNM stage III or IV disease. PET-CT was suspicious for pulmonary malignancy in 14 patients (22%) and indeterminate in 6 patients (9%). Pulmonary metastases or a new lung primary were present in 10 patients (16%): 7 of 14 patients with positive PET-CT scans (50%) and 3 of 50 patients with negative or indeterminate PET-CT scans (6%). Including nonpulmonary sites, the overall incidence of distant disease was 23% (15/64) with 20% (13/64) unsuspected prior to PET-CT. The sensitivity and specificity of PET-CT in predicting distant malignancy was 86% and 84%, respectively, with a positive predictive value of 60% and a negative predictive value of 95%. There was a significant correlation between standardized uptake value (SUV) on PET-CT and positive histology, with a mean SUV of 8.5 (range, 4.7-16.2) in patients with distant metastases compared with a mean SUV of 2.9 (range, 1.9-4.2) in patients with benign pathology (r = 0.87, P < .0001). CONCLUSIONS: A significant number of patients with recurrent HNSCC have distant metastases at the time of recurrence. These data suggest that PET-CT improves detection of metastatic disease in the high-risk patient and should be performed as part of the routine evaluation of patients with suspected recurrence prior to salvage surgery.

Identification of distant metastases with positron-emission tomography-computed tomography in patients with previously untreated head and neck cancer.

OBJECTIVES: To investigate the utility of positron-emission tomography-computed tomography (PET-CT) in identifying distant metastatic disease in patients with previously untreated head and neck squamous cell cancer (HNSCC) prior to definitive treatment. MATERIALS AND METHODS: Retrospective analysis of 27 consecutive patients with previously untreated HNSCC who underwent PET-CT imaging in addition to chest radiography (CXR) as part of their metastatic workup. RESULTS: The majority of patients (89%) had TNM stage III or IV disease. PET-CT was suspicious for pulmonary malignancy in four (15%) patients and indeterminate in one (4%) patient. CXR was suspicious for pulmonary malignancy in two (7%) patients. Pulmonary metastases or a new lung primary was present in 3 (11%) patients: 3 of 4 (75%) patients with positive PET-CT scans and 0 of 23 (0%) patients with negative or indeterminate PET-CT scans compared with 2 of 2 (100%) patients with positive CXR and 1 of 25 (4%) patients with negative CXR. The sensitivity and specificity of PET-CT in predicting pulmonary malignancy was 100% and 96%, respectively, with a positive predictive value of 75% and a negative predictive value of 100%. The sensitivity and specificity of CXR in predicting pulmonary malignancy was 67% and 100%, respectively, with a positive predictive value of 100% and a negative predictive value of 96%. Including nonpulmonary sites, the overall incidence of distant metastatic disease was 19% (5/27) with 11% (3/27) unsuspected prior to PET-CT. CONCLUSIONS: PET-CT improves detection of metastatic disease in the high-risk patient and should be performed as part of the routine pretreatment evaluation of patients with advanced stage HNSCC.

Malignancy in kaolin pneumoconiosis found with F-18 FDG positron emission tomography.

Kaolin pneumoconiosis may produce radiologic findings similar to those of malignancy. Current management includes serial radiologic examination and lung sampling of suspicious parenchymal opacities and nodules to exclude associated malignancy. This may result in unnecessary pulmonary resections in patients with already compromised lung function. In a patient with known kaolin pneumoconiosis and multiple nodules, we used positron emission tomography to identify suspicious areas for malignancy that were confirmed by open lung biopsy, leading to successful lung cancer treatment.

Functional imaging in temporal lobe epilepsy.

This article highlights the importance of functional imaging methods in the diagnosis and preoperative planning in temporal lobe epilepsy TLE). It starts with a discussion of the role of ictal and interictal single-photon emission computed tomography (SPECT) and interictal positron emission tomography (PET) in lateralizing TLE. The next section discusses the role of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) and perfusion MRI, particularly for lateralization of language and memory in TLE patients. The final section explores the relatively new role that the emerging technique of diffusion tensor imaging (DTI) is playing in the evaluation of TLE.