Utility of whole-body (head-to-toe) PET/CT in the evaluation of melanoma and sarcoma patients.

OBJECTIVE: The aim of this study was to assess the added benefit of whole-body (head-to-toes) PET/CT versus routine 'eyes-to-thighs' PET/CT of melanoma and sarcoma patients. PATIENTS AND METHODS: We performed a retrospective review of consecutive whole-body PET/CT scans from January 2006 through December 2010 in patients with melanoma or sarcoma. PET abnormalities in the brain, distal thighs, and legs were recorded and clinical significance was assessed on the basis of pathology, imaging studies, and clinical follow-up. Patients with known primary lesions distal to the proximal femora were excluded as these patients would routinely undergo 'head-to-toe' PET/CT. RESULTS: We reviewed reports from 352 PET/CT examinations in 194 patients with melanoma and 75 PET/CT examinations in 44 patients with sarcoma. Melanoma: 13 patients had brain metastases on PET. In five of these patients, lesions were unknown, but all were in the setting of other metastatic disease. Twenty-seven patients had lower extremity metastases, all in the setting of other metastatic disease. No lower extremity metastases were found in the remaining 167 patients. Sarcoma: one patient had an isolated, unexpected brain metastasis. Six patients had leg metastases, but none were isolated. No lower extremity metastases were found in the remaining 38 patients. CONCLUSION: In patients with melanoma and sarcoma, inclusion of entire lower extremities adds little additional clinical value as detection of isolated, unexpected metastasis is rare. Brain imaging may add value as the presence of brain metastases alters clinical management. Overall, in patients with melanoma or sarcoma, whole-brain PET/CT imaging may be of value, but routine inclusion of the entire lower extremities adds little additional value.

Optimal interpretative strategy for preoperative parathyroid scintigraphy.

PURPOSE: Our objective was to retrospectively compare various scintigraphic methods to determine their relative accuracies and interobserver variabilities in preoperative localization of single-gland disease in patients with primary hyperparathyroidism. PATIENTS AND METHODS: We studied 292 patients who underwent preoperative parathyroid scintigraphy and surgical resection between June 2002 and September 2008. Imaging included early and delayed pinhole Tc-MIBI imaging (including anterior oblique images), similar I imaging, and MIBI SPECT. Seven different imaging combinations were assessed as follows: early MIBI only, delayed MIBI only, comparison of dual-phase early and delayed MIBI, visual subtraction of early MIBI and I images, all planar images, SPECT only, and all planar and SPECT images (ALL). Each data set was reviewed by 2 of 4 experienced nuclear physicians without knowledge of clinical information or final diagnosis. Imaging results were compared with surgical outcomes. RESULTS: The accuracy of ALL imaging for delineating abnormal/normal parathyroid glands by quadrant was 96%, 93%, 95%, and 95% for the 4 readers. The accuracies of visual subtraction of early MIBI and I images and all planar images were not significantly different from ALL for all 4 readers. All planar and SPECT images were significantly more accurate than early MIBI only, delayed MIBI only, or SPECT only for all 4 readers and better than comparison of dual-phase early and delayed MIBI for 3 of 4 readers. CONCLUSIONS: A rigorous combination of multiple imaging approaches yielded high accuracies across multiple readers for localization of a single offending parathyroid gland, but a more limited technique using MIBI/I subtraction imaging with anterior and anterior oblique pinhole images provided similarly high accuracy and limited interobserver variation of accuracy.

Facelift and patterns of lymphatic drainage.

BACKGROUND: It has commonly been assumed that deeper facelift dissection causes greater and more prolonged swelling. OBJECTIVES: In this preliminary report, the authors compare the lymphatic reconstitution after multiple techniques of rhytidectomy by means of dynamic lymphoscintigraphy. METHODS: Three patients were enrolled in this study. All three were female, were similar in age, and exhibited similar signs and degrees of facial aging. Each woman underwent a facelift with a different technique: (1) subcutaneous dissection with superficial musculoaponeurotic system (SMAS) plication, (2) subcutaneous dissection with SMASectomy, and (3) a "high SMAS" composite facelift. Postoperatively, (99m)Tc-sulfur colloid was injected into a standardized infraorbital location in each patient to compare patterns of lymphatic drainage using lymphoscintigraphy. Postoperative scans at two weeks, six weeks, three months, six months, and one year were compared to the preoperative scans taken seven days prior to surgery. RESULTS: All rhytidectomy techniques appeared to temporarily create a significant and similar degree of interruption in lymphatic drainage. There was a subtotal recovery of lymphatic pathways within three months and complete return to baseline drainage pattern after six months, regardless of surgical technique. CONCLUSIONS: Based on the results of this study, it appears that the extent of facial dissection, rather than the depth, is the most significant factor in postoperative edema.

Visualization of discrete sacral foramina as an ancillary sign of superscan.

OBJECTIVES: the purpose of this study was to determine if visualization of discrete sacral foramina on bone scintigraphy can be used as an adjunct criterion supportive of a superscan diagnosis. METHODS: the Radiology Information System at our institution was queried for all bone scintigraphy reports, during July 1999 to July 2009, containing the words/phrases: normal bone scan, normal bone scintigraphy, superscan, or diffuse osseous metastatic disease. The final study group consisted of 22 normal studies and 8 superscans. All studies were reviewed by 2 nuclear medicine physicians who rated the examinations on a numeric scale of bone-to-soft tissue activity, whether they would classify the study as a superscan (based on previously published criteria), whether sacral foramina were visualized, and, if so, how many? RESULTS: of the 22 normal studies, no distinct sacral foramen was visualized in 17 cases. Of the 8 superscan patients, 1 patient demonstrated 8 foramina, 4 patients demonstrated 4 foramina, 1 patient demonstrated 3 foramina, and 2 patients demonstrated none. There was a statistically significant difference between the normal and superscan groups (P < 0.0017). Based on statistical analysis, it was determined that visualizing at least 3 distinct sacral foramina could be used as an ancillary finding to support the diagnosis of superscan. CONCLUSIONS: the ability to clearly visualize at least 3 sacral foramina is a statistically significant finding that may be useful as an ancillary criterion to differentiate normal bone scintigraphy from a superscan.

PET imaging today: contribution to the initial staging and prognosis of patients with non-Hodgkin's lymphomas.

Malignant non-Hodgkin lymphomas (NHLs) are commonly staged according to the Ann Arbor staging system developed for Hodgkin's lymphoma. Recently, new staging modalities including metabolic imaging by positron emission tomography (PET) using F-18 fluorodeoxy-glucose (FDG) have been developed. In the present study, we investigated 77 untreated patients with different histologies of NHL both with conventional imaging techniques and FDG-PET. The patients were classified according to the World Health Organization classification and came from 2 major PET imaging centers in Louisiana and Texas. Seventy-six of 77 cases of NHLs were positive by PET imaging. PET imaging resulted, both in high/intermediate grade and indolent NHLs, in a higher stage in more than 20% of cases. In the subtype of high grade NHL diffuse large B cell lymphoma, upstaging by PET appears to be clinically relevant as a marker for a more aggressive tumor. In low grade NHL, stage changes were less pronounced. PET imaging did not reliably detect all cases of bone marrow involvement (especially in indolent lymphomas). However, even in low-grade NHL, clear indications exist for performing PET imaging. The value, the clinical relevance, and new developments in PET imaging for the different types of NHLs are discussed in detail.

Use of PET/CT scanning in cancer patients: technical and practical considerations.

This overview of the oncologic applications of positron emission tomography (PET) focuses on the technical aspects and clinical applications of a newer technique: the combination of a PET scanner and a computed tomography (CT) scanner in a single (PET/CT) device. Examples illustrate how PET/CT contributes to patient care and improves upon the previous state-of-the-art method of comparing a PET scan with a separate CT scan. Finally, the author presents some of the results from studies of PET/CT imaging that are beginning to appear in the literature.