The continual innovation of commercial PET/CT solutions in nuclear cardiology: Siemens Healthineers.

Cardiac PET/CT is an evolving, non-invasive imaging modality that impacts patient management in many clinical scenarios. Beyond offering the capability to assess myocardial perfusion, inflammatory cardiac pathologies, and myocardial viability, cardiac PET/CT also allows for the non-invasive quantitative assessment of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Recognizing the need for an enhanced comprehension of coronary physiology, Siemens Healthineers implemented a sophisticated solution for the calculation of MBF and MFR in 2009. As a result, each aspect of their innovative scanner and image-processing technology seamlessly integrates into an efficient, easy-to-use workflow for everyday clinical use that maximizes the number of patients who potentially benefit from this imaging modality.

Single photon emission computed tomography (SPECT) should be routinely performed for the detection of parathyroid abnormalities utilizing technetium-99m sestamibi parathyroid scintigraphy.

RATIONALE: The current procedure guideline for performing dual-phase (DP) parathyroid scintigraphy, using technetium-99m sestamibi (Tc-99m MIBI) does not mandate the use of single photon emission computed tomography (SPECT) imaging for the detection of parathyroid adenoma (PA) or hyperplasia (PH). The aim of our study was to determine whether DP SPECT (DPS) is significantly superior to DP planar (DPP) imaging in the detection of these abnormalities, justifying its routine use with Tc-99m MIBI parathyroid scintigraphy. METHODS: Thirty-six consecutive patients with biochemically-proven hyperparathyroidism who subsequently underwent surgical evaluation were studied. All patients underwent early and delayed planar and SPECT imaging at 15 and 90 minutes postinjection of 1.11 GBq (30 mCi) of Tc-99m MIBI. The sensitivity and false-positive rate of DPP and DPS Tc-99m MIBI scintigraphy were compared by retrospectively and blindly interpreting the images and comparing the results with surgical findings. RESULTS: All 36 patients were shown to have either 1 PA (n=27), 2 PAs (n=1), or PH (n=8). Overall, 29 adenomas and 24 hyperplastic glands were found at surgery. On a per patient basis, the sensitivity for the detection of PA or PH for DPP was 42% (15/36) compared with 67% (24/36) for DPS (P = 0.03). For the detection of PAs, the sensitivity of DPP was 54% (15/28) versus 79% (22/28) for DPS (P = 0.05), whereas for the detection of PH, the sensitivities were 0% (0/8) for DPP versus 25% (2/8) for DPS (P = 0.13). There were 2 false-positive scans using DPP versus only 1 false-positive scan with DPS, resulting in false-positive rates of 7% and 4%, respectively. The combination of DPP and DPS did not add any advantage in detecting either PA or PH compared with DPS alone. CONCLUSIONS: DPS is significantly more sensitive, and at least as specific, compared with DPP in detecting parathyroid abnormalities in patients with primary hyperparathyroidism and should, therefore, be routinely used when DP Tc-99m MIBI is used in this setting. An algorithm for best utilization of this technique to determine the appropriate surgical approach in patients with primary hyperparathyroidism is presented.

A comparison between diagnostic I-123 and posttherapy I-131 scans in the detection of remnant and locoregional thyroid disease.

AIM OF STUDY: The aim of this study was to compare pretherapy diagnostic I-123 scans with 7-day posttherapy I-131 scans days in detecting remnant thyroid disease as well as locoregional metastases in patients who had undergone thyroidectomy for differentiated thyroid cancer. METHODS: The I-123 and I-131 scans from 53 patients were reviewed. The number of lesions identified on each scan was compared as well as the relative intensity of each lesion on the I-123 and I-131 scans using region-of-interest-derived lesion to background ratios. For the I-123 diagnostic scans, 1.0 to 1.6 mCi of activity was administered orally 24 hours before scan acquisition. Patients received therapeutic doses of I-131 ranging from 30.7 to 362.2 mCi orally, on the same day but after acquisition of the I-123 scan. All posttherapy I-131 scans were performed 7 days after radioablative therapy with I-131. RESULTS: Of the 53 patients, 14 had concordant scans, with an equal number of lesions detected by both scans. Thirty-nine I-123/I-131 scan pairs showed discordance, with 27 patients demonstrating more lesions on the I-123 scans. Of the 142 total lesions, 35% were detected only by I-123 pretherapy images compared with 15% detected only on posttherapy images. In a subgroup of 42 patients I-123 scans showed 56 lesions (out of a total of 116) that demonstrated either a better lesion to background ratio than I-131 or were seen exclusively by I-123. CONCLUSION: The use of diagnostic I-123 pretherapy scintigraphy seems to be superior in many patients to posttherapy I-131 imaging obtained at 7 days in detecting locoregional metastases or remnant in postsurgical patients. This is likely due to the fact that 1 week is too long to wait to perform posttherapy imaging.

Radionuclide cisternography in detecting cerebrospinal fluid leak in spontaneous intracranial hypotension: a series of four case reports.

Spontaneous intracranial hypotension (SIH) is an infrequent clinical entity characterized by cerebrospinal fluid (CSF) hypovolemia due to a CSF leak. The cause of the leak in SIH, however, is largely unknown, though structural meningeal weakness and mechanical stress factors have been postulated. Patients with SIH typically present with postural headaches, and occasionally with other symptomology as well, such as nausea, emesis, neck stiffness, and photophobia. In this case series, we present 4 patients who underwent radionuclide cisternography (RNC) for suspected CSF leak. All patients underwent RNC and MR and/or CT for evaluation. We found that RNC accurately detected and localized a CSF abnormality in all 4 patients, with each patient experiencing symptomatic relief following directed epidural blood patch.

Epstein-Barr virus mimicking lymphoma on FDG-PET/CT.

We report the case of a 17-year-old girl who presented with a several month history of fevers and abdominal pain. After cytomegalovirus (CMV) and Epstein-Barr virus (EBV) titers returned normal, FDG-PET/CT was obtained due to concern for lymphoma. FDG-PET/CT revealed a pattern of hypermetabolic activity in the adenoids, bilateral cervical lymph nodes, abdominal lymph nodes, and spleen, highly concerning for lymphoma. However, subsequent biopsy of a cervical lymph node revealed lymphadenitis consistent with EBV. This case highlights infection as the most well-known false-positive cause on FDG-PET, and how biopsy is essential to definitively distinguish malignancy from infection.