Retropharyngeal ectopic parathyroid adenoma versus lymph node: Problem solving with CT neck angiogram.

A 66-year-old female underwent preoperative evaluation for primary hyperparathyroidism. Ultrasound (US) neck and technetium (Tc)-99m-sestamibi planar scintigraphy were negative, but single photon emission computed tomography/computed tomography (SPECT/CT) demonstrated a tracer-avid retropharyngeal nodule compatible with parathyroid adenoma (PTA). A retrospective review of CT neck angiogram (CTA) and neck magnetic resonance imaging (MRI) performed 4 months earlier for stroke evaluation revealed arterial phase hyperenhancing retropharyngeal tissue, which had been dismissed as a nonpathological lymph node. "Polar vessel sign" seen in two-thirds of PTA was also present on retrospective review of the CTA. The concordant findings between SPECT/CT and CTA were indicative of a solitary undescended ectopic PTA in the retropharyngeal space, an uncommon location. A successful surgical cure was achieved after minimally invasive parathyroidectomy. This case highlights the retropharyngeal space as an important ectopic site of PTA, limitation of US, and Tc-99m-sestamibi planar scintigraphy in identifying retropharyngeal PTA. We also discuss the role of CT and MRI and the challenge in differentiating retropharyngeal PTA from a lymph node.

Radionuclide evaluation of patients with lymphoma.

Nuclear medicine imaging techniques allow us to peer into physiologic processes, avoiding the need to wait until anatomic changes are detectable, and allowing for prompt, informed management decisions. Recognition of normal, abnormal, and post-therapy scan patterns is critical to achieve the necessary sensitivity and specificity needed for patient management. Gallium scintigraphy using updated techniques has an important continuing role in management of patients with lymphoma. Gallium scintigraphy can contribute to patient management primarily by detecting residual disease or relapse after treatment, monitoring response during therapy, and providing prognostic information. FDG and PET cameras, especially dedicated ring systems, offer high resolution and high-contrast images, thereby demonstrating additional sites of disease. Although preliminary evidence looks promising that FDG can provide all information that Ga-67 has been shown to do in the past, additional data are required. Further studies will show whether FDG-PET can provide prognostic information and predict disease-free and overall survival, the availability of both FDG and PET scanners, and issues of cost. Patient accessibility will undoubtedly also play a role in when, or whether, FDG-PET will totally replace Ga-67 scintigraphy in the management of patients with lymphoma.

Gallium-67 scintigraphy in the management: Hodgkin's disease and non-Hodgkin's lymphoma.

Gallium scintigraphy has an important role in the management of patients with lymphoma. It contributes to patient management by detecting residual disease or relapse after treatment, monitoring response during therapy, and providing prognostic information.

Epiphyseal photopenia associated with metaphyseal osteomyelitis and subperiosteal abscess.

We present a case of metaphyseal osteomyelitis in a child where bone scintigraphy demonstrated photopenia of the distal femoral epiphysis in the absence of infection of the epiphysis or the joint space. A subsequent bone scan demonstrated evolution of the vascular compromise of the epiphysis due to the metaphyseal osteomyelitis complicated by subperiosteal abscess. We discuss the mechanisms and implications of photopenia in the setting of acute bone and joint infection.

Extensive photopenic osteomyelitis.

We present a case of a previously healthy child whose osteomyelitis and septic arthritis resulted in unusually extensive photopenia on bone scintigraphy. Uptake was absent in the humeral shaft and proximal epiphysis and decreased in the proximal physis. The subsequent complicated clinical course, including surgical interventions, and bone scans is described.

Frequency of extra-cardiac activity and its effect on 99Tcm-MIBI cardiac SPET interpretation.

There are limited published data concerning the frequency and relative intensity of abdominal activity on 99Tcm-methoxyisobutyl isonitrile (99Tcm-MIBI) myocardial perfusion scans and its effect on interpretation. We undertook a blinded prospective study to evaluate (1) the frequency and intensity of abdominal activity on single photon emission tomography (SPET) scans, (2) its effect on separate evaluation of rest and stress SPET images, and (3) its effect on clinical interpretation. Patients undergoing one-day rest-stress 99Tcm-MIBI scans were randomized to receive 99Tcm-MIBI obtained from one of two radiopharmacies. The rest plus exercise or rest plus intravenous dipyridamole scans of 303 patients were scored separately by three physicians for (1) intensity of abdominal activity and (2) its effect on scan evaluation. Nuclear reports generated independently of the blinded evaluation were reviewed to assess the effect of abdominal activity on clinical interpretation. There were no statistical differences between pharmacies. Abdominal activity was uncommon on the exercise but common on the rest and dipyridamole scans. The exercise scans differed from the rest and dipyridamole scans in the subgroups: intensity of abdominal activity equal to myocardium, and greater than myocardium (P < 0.001). There was no difference between the rest and dipyridamole scans. The effect on evaluation was moderate in 5% of the exercise, 46% of the dipyridamole and 37% of the rest scans, and severe in 1% of the exercise, 3% of the dipyridamole and 12% of the rest scans. Rest differed from exercise (P < 0.001) and from dipyridamole (P < 0.05). There was no difference between the dipyridamole and exercise scans. Based on the clinical reports, abdominal activity was a limitation to scan interpretation for 20 patients; in 5, the inferior wall could not be evaluated. Although abdominal activity was frequently observed on both the dipyridamole and rest scans, it was a limitation to clinical interpretation in a small fraction of the patients.

Positive technetium-99m-red blood cell gastrointestinal bleeding scan after barium small-bowel study.

A 53-yr-old man with hepatic insufficiency and portal hypertension was hospitalized and underwent a work-up for gastrointestinal bleeding requiring multiple transfusions. The initial evaluation included a negative upper and lower endoscopy and a barium exam of the small bowel. Both studies failed to demonstrate any pathology to explain the bleeding. Immediately following the barium study, the patient had active bleeding. Because of the significant amount of intestinal barium, angiography was deferred. Technetium-99m-red blood cell (RBC) scintigraphy was undertaken to identify the site of bleeding. Despite intestinal barium, the 99m-Tc-RBC scan demonstrated an active bleeding site in the small bowel in the left abdomen. Therefore, 99mTc-RBC scintigraphy can be of clinical utility for identification of gastrointestinal bleeding, despite the presence of intestinal barium.

A simple and accurate grading system for orthoiodohippurate renal scans in the assessment of post-transplant renal function.

Orthoiodohippurate renal scanning has proved to be a reliable, noninvasive method for the evaluation and followup of renal allograft function. However, a standardized system for grading renal function with this test is not available. We propose a simple grading system to distinguish the different functional phases of hippurate scanning in renal transplant recipients. This grading system was studied in 138 patients who were evaluated 1 week after renal transplantation. There was a significant correlation between the isotope renographic functional grade and clinical correlates of allograft function such as the serum creatinine level (p = 0.0001), blood urea nitrogen level (p = 0.0001), urine output (p = 0.005) and need for hemodialysis (p = 0.007). We recommend this grading system as a simple and accurate method to interpret orthoiodohippurate renal scans in the evaluation and followup of renal allograft recipients.

Reduction of intrapulmonary shunt and resolution of digital clubbing associated with primary biliary cirrhosis after liver transplantation.

This report describes a patient with marked hypoxemia caused by intrapulmonary shunt associated with primary biliary cirrhosis. Liver transplantation resulted in resolution of digital clubbing and reduction of intrapulmonary shunt as demonstrated by normalization of room air arterial blood gases, reduction in shunt fraction and normalization of the indocyanine-enhanced echocardiogram and perfusion lung scan. This patient's course challenges the conventional notion that intrapulmonary shunting associated with chronic liver disease does not reverse after liver transplantation.