Is Nuclear Imaging Important in the Management of Head and Neck Paragangliomas?

Nuclear medical imaging is indicated in most, but not all, patients with suspected paragangliomas of the head and neck. Advances in technology and somatostatin receptor analogs have improved the selectivity and sensitivity of this imaging.

Neuroradiological and Neuropathological Changes After 177Lu-Octreotate Peptide Receptor Radionuclide Therapy of Refractory Esthesioneuroblastoma.

BACKGROUND AND IMPORTANCE: Olfactory neuroblastoma, also known as esthesioneuroblastoma (ENB), is a malignant neoplasm with an unpredictable behavior. Currently, the widely accepted treatment is inductive chemotherapy, with or without surgery, followed by radiotherapy. Since data on genetics and molecular alterations of ENB are lacking, there is no standard molecularly targeted therapy. However, ENB commonly expresses the somatostatin receptor (SSTR) that is also expressed by neuroendocrine tumors. Peptide receptor radionuclide therapy (PRRT) using radiolabeled somatostatin analogues, such as 177Lu-octreotate, is an effective treatment for the latter. We present the complex neuroradiological and neuropathological changes associated with 177Lu-octreotate treatment of a patient with a highly treatment-resistant ENB. CLINICAL PRESENTATION: A 60-yr-old male presented with an ENB that recurred after chemotherapy, surgery, stereotactic radiosurgery, and immunotherapy. Pathology revealed a Hyams grade 3 ENB and the tumor had metastasized to lymph nodes. Tumor SSTR expression was seen on 68Ga-octreotate positron emission tomography (PET)/computed tomography (CT), suggesting that PRRT may be an option. He received 4 cycles of 177Lu-octreotate over 6 mo, with a partial response of all lesions and symptomatic improvement. Four months after the last PRRT cycle, 2 of the lesions rapidly relapsed and were successfully resected. Three months later, 68Ga-octreotate PET/CT and magnetic resonance imaging indicate no progression of the disease. CONCLUSION: We describe imaging changes associated with 177Lu-octreotate PRRT of relapsing ENB. To our knowledge, this is the first report describing neuropathological changes associated with this treatment. PRRT is a promising therapeutic option to improve the disease control, and potentially, the survival of patients with refractory ENB.

Bone SPECT/CT of the Spine, Foot, and Ankle: Evaluation of Surgical Patients.

Radionuclide bone scanning has been used routinely in the evaluation of bone pathology for decades. The greatest strength of the procedure is its extreme sensitivity for bone metabolism, allowing it to distinguish between active and inactive bony abnormalities. The downside of this reliance on abnormal bone turnover is the relative lack of anatomical detail compared with ever-improving CT and MRI technology. Fusion imaging using SPECT/CT (SCT), PET/CT, and PET/MRI offers an opportunity to combine the sensitivity of nuclear medicine examinations with the anatomical detail of CT and MRI. This fusion of technologies is especially important in situations where anatomical imaging modalities alone provide insufficient diagnostic information. In this review, we highlight the utility of SPECT/CT bone imaging in the pre- and postoperative evaluation of patients undergoing procedures of the spine, foot, and ankle.

Bone SPECT/CT in skeletal trauma.

The utility of radionuclide bone scanning in skeletal trauma has been greatly enhanced over the last decade by hybrid technology merging multislice CT with SPECT that can take advantage of CT-based correction of attenuation and scatter. The resulting images have been particularly helpful in giving us new insights into the evaluation of foot and ankle injuries and vertebral pathology both before and after surgery. The physiological information and anatomical detail allow a better understanding of the causes of patients' pain and have proven to be particularly useful in planning surgical intervention.

ACR appropriateness criteria acute hip pain-suspected fracture.

Substantial cost, morbidity, and mortality are associated with acute proximal femoral fracture and may be reduced through an optimized diagnostic imaging workup. Radiography represents the primary diagnostic test of choice for the evaluation of acute hip pain. In middle aged and elderly patients with negative radiographs, the evidence indicates MRI to be the next diagnostic imaging study to exclude a proximal femoral fracture. CT, because of its relative decreased sensitivity, is only indicated in patients with MRI contraindications. Bone densitometry (DXA) should be obtained in patients with fragility fractures. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Agreement between SPECT V/Q scan and CT angiography in patients with high clinical suspicion of PE.

OBJECTIVE: To track agreement between single positron emission computed tomography (SPECT) V/Q and CT angiography in patients with high clinical suspicion of pulmonary embolism (PE). If significant agreement occurs, a case could be made for more frequent use of chest radiography followed by SPECT V/Q scanning given its lower risk profile. INTRODUCTION: Diagnosis of PE can be difficult. CT pulmonary angiography (CTA) is the preferred initial test, but may be indeterminate, is a significant source of ionizing radiation, and is contraindicated in renal insufficiency. SPECT ventilation/perfusion imaging (V/Q) is therefore preferred in certain patients. METHODS: Two thousand nine hundred and twenty patients admitted to a tertiary care hospital in New York City were screened and 100 consecutive high-risk patients who required both CTA and V/Q for an initial indeterminate or negative imaging test despite a high pre-test probability were identified. The agreement between these tests was evaluated. RESULTS: There was no significant agreement between CTA and V/Q when positive, negative and indeterminate results were included (K = 0.18, SE = 0.09, p = 0.051). However, in the presence of a positive finding on either test, there was substantial agreement between the two (K = 0.62, SE = 0.27, p = 0.02). In 30 cases in which CTA was indeterminate, V/Q was diagnostic 93 % of the time. In 12 cases in which V/Q was indeterminate, CTA was diagnostic 83 % of the time and negative in 100 % of those cases. CONCLUSION: In the presence of an indeterminate CTA in patients with high clinical suspicion of PE, SPECT V/Q often provides a diagnosis.

ACR appropriateness criteria(®) acute trauma to the knee.

There are more than 1 million visits to the ER annually in the United States for acute knee trauma. Many of these are twisting injuries in young patients who can walk and bear weight, and emergent radiography is not required. Several clinical decision rules have been devised that can considerably reduce the number of radiographic studies ordered without missing a clinically significant fracture. Although fractures are seen on only 5% of emergency department knee radiographs, 86% of knee fractures result from blunt trauma. In patients with falls or twisting injuries who have focal tenderness, effusion, or inability to bear weight, radiography should be the first imaging study performed. If radiography shows no fracture, MRI is best for evaluating for a suspected meniscal or ligament tear or patellar dislocation. Patients with knee dislocation should undergo radiography and MRI, as well as fluoroscopic angiography, CT angiography, or MR angiography. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

SPECT/CT in the management of osteochondral lesions of the talus.

BACKGROUND: The treatment of osteochondral lesion of the talus (OLT) is mainly based upon the stage of the disease so accurate imaging is crucial. SPECT/CT combines bone scan with high-resolution CT and can provide functional-anatomical images in a single stage. The purpose of this study was to assess the value of SPECT/CT in the management of OLT. MATERIALS AND METHODS: From 2004 to 2009, 22 patients with OLT were identified that had both SPECT/CT and MRI of the foot and ankle. All charts were reviewed to ascertain the reason for ordering the SPECT/CT and the additional information obtained. AOFAS outcome scores were calculated at the time of followup. RESULTS: Twelve patients underwent ankle arthroscopy for debridement or drilling of the osteochondral lesion. The mean AOFAS score in these 12 patients was 83.6. SPECT/CT helped preoperative planning by identifying the exact location of the active lesion, especially in multifocal disease or revision surgeries while showing the depth of the active lesion. Ten patients had conservative management due to minimal or no activity over the lesion on SPECT/CT images. The mean AOFAS score in these ten patients was 78.8 which was comparable to the operative group. CONCLUSION: We believe SPECT/CT was able to provide additional diagnostic value by demonstrating a co-existing pathology as a potential cause of pain and in preoperative planning by showing the depth of activity and the precise location of the active segment in multiple lesions.

The poppy seed test for colovesical fistula: big bang, little bucks!

PURPOSE: Diagnosis of a colovesical fistula is often challenging, and usually involves numerous invasive and expensive tests and procedures. The poppy seed test stands out as an exception to this rule. We evaluated the accuracy and cost-effectiveness of various established diagnostic tests used to evaluate a suspected colovesical fistula. MATERIALS AND METHODS: We identified 20 prospectively entered patients with surgically confirmed colovesical fistulas between 2000 and 2006. Each patient was evaluated preoperatively with a (51)chromium nuclear study, computerized tomography of the abdomen and pelvis with oral and intravenous contrast medium, and the poppy seed test. Costs were calculated using institutional charges, 2006 Medicare limiting approved charges and the market price, respectively. The z test was used to compare the proportion of patients who tested positive for a fistula with each of these modalities. RESULTS: The chromium study was positive in 16 of 20 patients (80%) at a cost of $490.83 per study. Computerized tomography was positive in 14 of 20 patients (70%) at a cost of $652.92 per study. The poppy seed test was positive in 20 of 20 patients (100%) at a cost of $5.37 per study. The difference in the proportion of patients who tested positive for a fistula on computerized tomography and the poppy seed test was statistically significant (p = 0.03). There was no difference between the chromium group and the computerized tomography or poppy seed group (p = 0.72 and 0.12, respectively). CONCLUSIONS: The poppy seed test is an accurate, convenient and inexpensive diagnostic test. It is an ideal initial consideration for evaluating a suspected colovesical fistula.