Treatment of Primary Liver Tumors and Liver Metastases, Part 1: Nuclear Medicine Techniques.

90Y radioembolization is an increasingly used treatment for both primary and metastatic malignancy in the liver. Understanding the biophysical properties, dosing concerns, and imaging appearance of this treatment is important for interventional radiologists and nuclear medicine physicians to provide important therapy. 90Y radioembolization is efficacious and safe, although the possibility of complications does exist. This article provides a comprehensive in-depth discussion about the indications for 90Y radioembolization, reviews the role of preprocedural angiography and 99mTc-macroaggregated albumin scans, illustrates different dosing techniques, compares and contrasts resin and glass microspheres, and describes potential complications.

The ideal dual-isotope imaging combination in evaluating patients with suspected infection of pelvic pressure ulcers.

INTRODUCTION: The successful management of infected pelvic pressure ulcer patients (PPUP) depends on the distinction between infections limited to soft tissue (STI) and those with underlying osteomyelitis (OM), which can be difficult to determine clinically. Dual-isotope (DI) comprehensive imaging has excellent accuracy in localizing diabetic foot infection and differentiating OM from STI with SPECT/CT utilization. In this study, we assess the accuracy and confidence of the different DI SPECT/CT imaging steps in PPUP with confirmed diagnoses. PATIENTS AND METHODS: Pelvic flow and blood pool imaging were followed by labeled white blood cell reinjection and Tc-99m hydroxymethylene-diphosphonate bone (bone scan) and In-111-leukocytes (white blood cell scan) DI planar and SPECT/CT (step 1) acquisitions. Tc-99m sulfur colloid (bone marrow scan)/WBCS SPECT/CT (step 2) images were obtained on the following day. DI step 1 planar, step 1 SPECT/CT, step 2 SPECT/CT, and combined step 1/step 2 SPECT/CT were reviewed separately for diagnosis and diagnosis confidence. The final diagnosis was confirmed by culture/pathology in 21 patients and clinical/imaging follow-up in 12 patients. RESULTS: There were 19 OM patients, three STI patients, and 11 patients with no infection. The final diagnosis agreement to DI combined step 1/step 2 SPECT/CT was higher than DI step 2 or step 1 SPECT/CT alone, or DI step 1 planar, as assessed by λ and error reduction %, respectively. Combined DI step 1/step 2 SPECT/CT was more sensitive than DI step 2 SPECT/CT and more specific than DI step 1 SPECT/CT, and showed higher diagnostic confidence than both imaging techniques. CONCLUSION: DI SPECT/CT is highly useful in evaluating PPUP with suspected infection. DI step 1 is more sensitive, whereas step 2 is more specific. Both step 1 and step 2 DI SPECT/CT images are needed to accurately and confidently assess for infection and distinguish OM from STI, which are crucial for optimal management.

Direct comparison of neck pinhole dual-tracer and dual-phase MIBI accuracies with and without SPECT/CT for parathyroid adenoma detection and localization.

INTRODUCTION: There is uncertainty about accuracies of dual-phase (DP) and dual-tracer (DT) parathyroid scintigraphy with the newly added SPECT/CT. Although SPECT/CT was shown to be helpful in parathyroid adenoma (PA) localization, it may not have optimal resolution as pinhole. This study directly compared diagnostic accuracies and confidences of various imaging protocols on same patients. PATIENTS AND METHODS: One hundred fifty-five patients with pathologically confirmed diagnosis were included. Pinhole DP, pinhole DT, pinhole DP SPECT/CT, pinhole DT SPECT/CT, and SPECT/CT with only pinhole-delayed MIBI (D) were reviewed for accuracies and certainties of PA diagnosis/localization. Parathyroid adenomas were classified as clearly or unclearly distinguishable from thyroid. Furthermore, the contribution of pinhole DP to pinhole DT SPECT/CT was assessed. RESULTS: Of 153 PAs, the correct diagnosis/localization was significantly higher by pinhole DT SPECT/CT than pinhole DP SPECT/CT, SPECT/CT D, pinhole DT alone, and DP alone. Parathyroid adenomas were clearly more distinguished from thyroid in pinhole DT than DP with/without SPECT/CT. Consequently, PA diagnosis certainty was higher in pinhole DT than DP, whereas PA localization certainty was higher in both with SPECT/CT. In pinhole DT SPECT/CT, the pinhole DP addition confirmed diagnosis/localization of only 24 uncertain PAs. CONCLUSIONS: In this large patient group, the accuracy and certainty of PA diagnosis/localization were higher in pinhole DT SPECT/CT than all other parathyroid scintigraphy protocols. Pinhole DT better identified PA than pinhole DP, whereas SPECT/CT improved PA localization in both protocols. Pinhole DP showed limited contribution and thus should be only considered when PA diagnosis/localization is uncertain by pinhole DT SPECT/CT.

The optimized evaluation of diabetic foot infection by dual isotope SPECT/CT imaging protocol.

Sequential Tc-99m hydroxymethylene-diphosphonate (HDP) 3-phase bone (BS) and In-111 leukocyte scanning (WBCS) have been frequently used to evaluate the diabetic foot, as nonosteomyelitis BS uptake is repeatedly observed and osteomyelitis (OM) in WBCS is often uncertain without BS correlation. Additionally, both modalities are limited in lesion localization because of low resolution and lack of anatomic details. We investigated a method that combined BS/WBCS, and if needed, WBCS/bone marrow scanning (BMS) using SPECT/CT to accurately diagnose/localize infection in a practical protocol. Blood flow/pool images were obtained followed by WBC reinjection and next day dual isotope (DI) BS/WBCS planar and SPECT/CT. BMS/WBCS SPECT/CT (step 2 DI) was obtained on the following day when images were suspicious for mid/hindfoot OM. Diagnosis accuracy and confidence were judged for the various imaging combinations. Diagnosis was classified as OM, soft tissue infection (STI), both OM/STI, and other/no bony pathology by microbiology/pathology or follow-up. Distinction between various diagnostic categories and overall OM diagnostic accuracy in 213 patients were higher for DI than WBCS or BS alone, and for DI SPECT/CT than DI planar or SPECT only. Diagnostic confidence/lesion site was significantly higher for DI SPECT/CT than other comparative imaging methods. In a group of 97 patients with confirmed microbiologic/pathologic diagnosis, similar results were attained. Step 2 DI SPECT/CT performed in 67 patients further improved diagnostic accuracy/confidence. DI SPECT/CT is a highly accurate modality that considerably improves detection and discrimination of STI and OM while providing precise anatomic localization in the diabetic foot. This combined imaging technique promises to beneficially impact diabetic patient care.

PET/CT image fusion error due to urinary bladder filling changes: consequence and correction.

OBJECTIVE: A considerable change of urinary bladder (UB) shape in PET compared with CT in integrated PET/CT system is frequently noted. This study initially evaluated this finding with and without oral contrast (OC) use. In addition, a one bed pelvic section (PLV) repeat acquisition was investigated as a solution to this problem. METHODS: (18)FDG PET/CTs of 88 patients were analyzed. OC was administered in 68 patients, of whom 31 had PLV images taken 5-10 min later. Three-dimensional mid-UB CT and PET matching measurements were compared. In addition, UB walls displacement between CT and PET were analyzed. RESULTS: The mean UB height was significantly increased (P < 0.001) in PET when compared with CT, both anteriorly and posteriorly; however, UB width and depth were not significantly different. An upward shift of superior UB wall in PET from equivalent CT images was noted, whereas there was no appreciable displacement of the other UB walls. The percent UB height increase on PET from CT was significantly greater with than without OC use. The UB height difference between PET and CT was markedly reduced on PLV when compared with the original scans. CONCLUSIONS: Caution should be exerted during the interpretation of PET/CT scans of the pelvis as there is significant upward expansion of UB on PET compared with CT that appears to be exaggerated by OC use, likely due to additional fluid load. The PET/CT fusion errors of UB can be substantially resolved through a separate PLV acquisition presumably due to the shorter time interval of UB scan completion between CT and PET.

Usefulness of 123I-MIBG scintigraphy in the evaluation of patients with known or suspected primary or metastatic pheochromocytoma or paraganglioma: results from a prospective multicenter trial.

UNLABELLED: Although (123)I-MIBG has been in clinical use for the imaging of pheochromocytoma for many years, a large multicenter evaluation of this agent has never been performed. The present study was designed to provide a prospective confirmation of the performance of (123)I-MIBG scintigraphy for the evaluation of patients with known or suspected primary or metastatic pheochromocytoma or paraganglioma. METHODS: A total of 81 patients with a prior history of primary or metastatic pheochromocytoma or paraganglioma and 69 with suspected pheochromocytoma or paraganglioma based on symptoms of catecholamine excess, CT or MRI findings, or elevated catecholamine or metanephrine levels underwent whole-body planar and selected SPECT 24 h after the administration of (123)I-MIBG. Images were independently interpreted by 3 masked readers, with consensus requiring agreement of at least 2 readers. Final diagnoses were based on histopathology, correlative imaging, catecholamine or metanephrine measurements, and clinical follow-up. RESULTS: Among 140 patients with definitive diagnoses (91, disease present; 49, disease absent), (123)I-MIBG planar scintigraphy had a sensitivity and specificity of 82%. For patients evaluated for suspected disease, sensitivity and specificity were 88% and 84%, respectively. For the subpopulations of adrenal (pheochromocytoma) and extraadrenal (paraganglioma) tumors, sensitivities were 88% and 67%, respectively. The addition of SPECT increased reader confidence but minimally affected sensitivity and specificity. CONCLUSION: This prospective study demonstrated a sensitivity of 82%-88% and specificity of 82%-84% for (123)I-MIBG imaging used in the diagnostic assessment of primary or metastatic pheochromocytoma or paraganglioma.

Combined rest redistribution thallium-201 SPECT and low-dose dobutamine contractility assessment in a simple and practical new viability protocol.

OBJECTIVE: Rest-redistribution (RR) thallium-201 (Tl-201) imaging is commonly used for myocardial viability evaluation. Contractile reserve (CR) assessment with low-dose dobutamine (LDD) is another method that highly predicts functional recovery following revascularization. In this study, we investigate the feasibility of a new protocol that provides combined Tl-201 uptake, resting and CR functional regional myocardial information in a single examination. METHODS: A total of 41 patients underwent RR-gated-SPECT Tl-201 myocardial perfusion imaging. The LDD infusion was maintained during delayed imaging. Segmental Tl-201 uptake was classified into normal, fixed decrease (mild to absent) and reversible, and sub-classified by wall motion (WM)/thickening (WT) changes between early resting and delayed LDD gated images into normal, fixed or improved dysfunctional (CR present) segments. RESULTS: Out of 820 examined segments, 33 showed no appreciable Tl-201 uptake to evaluate WM/WT. In a dysfunctional myocardium, CR was significantly higher (P < 0.001) in reversible and fixed than in normal Tl-201 segments. The CR in dysfunctional segments with fixed decrease Tl-201 uptake was significantly higher (P < 0.05) in mild and moderate than in severe fixed defects. Both fixed Tl-201 defects and lack of CR were observed more (P < 0.05) in akinetic/dyskinetic than in hypokinetic segments. CONCLUSIONS: Simultaneous assessment of myocardial viability by RR Tl-201 uptake, resting and CR functional regional information is feasible and can be easily attained using this new protocol. Moreover, this protocol requires no additional time or radioactivity when compared with the usual RR Tl-201 protocol. Validation of this protocol with patients' revascularization data is needed.

Value of precise localization of recurrent multiple myeloma with F-18 FDG PET/CT.

A 37-year-old man with multiple myeloma in remission underwent routine fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) study for disease restaging. Both FDG-PET and CT images showed focal abnormalities in the region of the T6 vertebra, but the fused images that are routinely provided with PET/CT could precisely localize the FDG active lesion to a soft tissue focus in the epidural space, away from a lytic nonactive vertebral body lesion despite their close proximity. The PET/CT scan identified a few other metabolically active osseous lesions out of many lytic bony changes throughout the skeleton. Accordingly, the patient received the correct management for an impending spinal cord compression at the appropriate time, in addition to systemic therapy for disease relapse.

The distinctive role of positron emission tomography/computed tomography in breast carcinoma with brown adipose tissue 2-fluoro-2-deoxy-d-glucose uptake.

The diagnostic power of an integrated positron emission tomography/computed tomography (PET/CT) system for whole-body 2-fluoro-2-deoxy-d-glucose (FDG) imaging is clearly demonstrated in this case report. The precise anatomic localization of FDG uptake with CT in a PET/CT scan of a patient with known breast carcinoma helped identify a contralateral breast tumor with axillary lymph node metastasis despite the presence of extensive physiologic brown fat FDG uptake. Accordingly, the patient received appropriate surgical management and pathologic confirmation of the disease.

PET/CT F-18 FDG scan accurately identifies osteoporotic fractures in a patient with known metastatic colorectal cancer.

Positron emissions tomography/computed tomography (PET/CT) scan has been used in many types of cancer to characterize the extent of disease as well as to identify the presence of metastases. However, the utility of PET/CT in patients with both cancer and osteoporosis is less well delineated. In this case, a patient with known metastatic colorectal cancer who was investigated by many forms of conventional imaging for back and pelvic pain was found to have osteoporotic fractures using PET/CT. At the same time malignant disease was excluded.

Alternative lymphatic pathway after previous axillary node dissection in recurrent/primary breast cancer.

OBJECTIVES: The sentinel lymph node approach has almost become the standard procedure of choice in the management of patients with early breast cancer. The status of sentinel nodes, whether or not pathologically involved by cancer cells, represents those of the axillary nodes with a negative predictive value of almost 100%. If the axillary lymphatic nodal drainage is altered, alternative lymphatic pathways and accordingly sentinel node location will be changed. METHODS: In this article, 4 patients are presented, 3 with recurrent breast cancer who had already undergone lumpectomy, axillary node dissection, and radiotherapy in the past and 1 with primary breast cancer after surgical removal of a malignant melanoma on her back and had axillary node dissection on the same side as the breast cancer. These patients underwent lymphoscintigraphy followed by sentinel node localization using the gamma probe and also blue dye injection during surgery. RESULTS: All patients showed alternate lymphatic pathways, 1 had an ipsilateral internal mammary node and crossed lymphatics to a contralateral axillary node, 2 had intramammary sentinel nodes, and 1 had an internal mammary on the same side. Pathologic examination of the intramammary and contralateral sentinel nodes were negative for metastases. Internal mammary sentinel nodes were not biopsied. CONCLUSION: We feel that sentinel node lymphoscintigraphy should be done even in patients who have altered lymphatic pathways resulting from previous axillary node dissection. It allows identifying and biopsy of the sentinel node at its new unpredicted location.

Value of low-dose dobutamine addition to routine dual isotope gated SPECT myocardial imaging in patients with healed myocardial infarction or abnormal wall thickening by echocardiogram.

There is overlap in myocardial viability detection by thallium-201 uptake and contractile reserve (CR) using low-dose dobutamine (LDD). The dual isotope protocol was modified in this study by acquiring thallium-201 images using LDD to enhance viability detection in addition to coronary flow reserve assessment. One hundred twenty-four patients with coronary disease underwent gated single-photon emission computed tomographic thallium-201 imaging at rest with LDD (10 microg/kg/min) during acquisition followed by stress technetium-99m sestamibi myocardial perfusion (MP) imaging with dobutamine, adenosine, or treadmill exercise. F-18-fluorodeoxyglucose (FDG) positron emission tomography was obtained in 41 patients. Myocardial perfusion (MP) imaging was divided into normal, fixed, and ischemic segments, and subclassified by wall motion and/or thickening changes between 1-hour poststress and LDD into normal, fixed, or improved dysfunctional segments (CR present). Mean left ventricular ejection fraction was 39% at 1 hour after stress and 47% with LDD (p <0.001). In dysfunctional myocardium, CR was significantly higher (p <0.001) in ischemic (233 of 368) and fixed segments (150 of 335) than in normal MP segments (43 of 220). Combined MP and CR analysis showed higher accuracy and negative predictive value in identifying FDG-viable myocardium than either method alone, whereas a high positive predictive value was maintained, similar to both markers. Quantitative analysis showed significant increased wall motion and thickening with LDD compared with 1 hour after stress, which was highest in ischemic segments and lowest in fixed segments. Thus, LDD dual isotope is a practical protocol that improves viability detection by simultaneous MP and CR analysis in addition to coronary flow reserve assessment in 1 study. Moreover, it requires no extra imaging time or radioactivity than the routine protocol.

Retrospective analysis of sentinel node localization in multifocal, multicentric, palpable, or nonpalpable breast cancer.

UNLABELLED: Multicentric or multifocal breast cancer is considered as one of the limitations for sentinel lymph node (SLN) localization. We did a retrospective analysis to evaluate the success rate, sensitivity, accuracy, and negative predictive values of SLN localization in multicentric or multifocal breast lesions. METHODS: Fifty-nine patients with multifocal or multicentric breast lesions proven by either fine-needle aspiration (19/59), core biopsy (39/59), or lumpectomy (8/59) underwent SLN localization. Of these patients, 46 had SLN localization by both radiocolloid and blue dye, and 13 had SLN localization by radiocolloid alone. Approximately 10 MBq (99m)Tc-labeled unfiltered sulfur colloid in 0.3-0.4 mL were injected intradermally over the 1 or 2 breast tumor locations 2-4 h before surgery. During surgery, vital blue dye was injected intraparenchymally in 4-6 places around the tumor. All lymph nodes with counts of >10 times that of the background counts, whether or not blue dye positive, and all blue dye-positive lymph nodes, whether or not radiocolloid positive, were excised and labeled accordingly. All lymph nodes underwent frozen sectioning and were examined by hematoxylin and eosin and immunohistologic (cytokeratin) staining. RESULTS: Of the 59 patients, 48 had axillary lymph node dissection irrespective of the results of pathologic examination of the SLN. The success rate, sensitivity, negative predictive value, and accuracy were 93%, 100%, 100%, and 100% using the radiocolloid probe, 87%, 100%, 100%, and 100% using blue dye, and 93.5%, 100%, 100%, and 100% using combined methods, respectively. Concordance between blue dye and radiocolloid was 91% (the incidence of the number of sentinel nodes detected was 37.5%, 30.3%, 10.7%, and 21.4% for 1, 2, 3, and 4 or more lymph nodes, respectively). Metastatic lymph node involvement was found in 39.5% of patients. CONCLUSION: The sentinel node localization approach showed a high negative predictive value in breast cancer patients with multifocal or multicentric lesions, contrary to the common belief of significant false-negative results in these patients.

Transient postischemic stunning evaluation by stress gated Tl-201 SPECT myocardial imaging: Effect on systolic left ventricular function.

BACKGROUND: Transient postischemic stunning (TIS) has been reported in images obtained (1/2) to 1 hour after stress with technetium 99m tracers but has not been investigated in images obtained shortly after stress with thallium 201. We also quantified the global extent and severity of TIS, which has not been done previously. METHODS AND RESULTS: We evaluated 82 patients with either treadmill or dobutamine stress Tl-201 myocardial perfusion imaging. Images were semiquantitatively examined with a 20-segment model. The extent and severity of myocardial ischemia and TIS were assessed by the summed difference score from the early and delayed scores of perfusion, wall motion (WM), and wall thickening (WT). The mean left ventricular ejection fraction (LVEF) was significantly lower in early images than in delayed images in patients with ischemia (P <.01), TIS by WM (P <.001), and TIS by WT (P <.001), and the LVEF difference was more significantly different as the summed difference score of perfusion, WM, or WT increased. No significant LVEF difference was seen in patients with ischemia who did not have TIS. CONCLUSIONS: In stress gated Tl-201 single photon emission computed tomography myocardial perfusion imaging, early TIS is frequently seen in patients with ischemia and is equivalently detected by WM and WT assessments. Significant exercise-induced transient left ventricular global dysfunction is associated with more severe and extensive ischemia and can be predicted by the measurement of the extent and severity of TIS from the same images.

Transient ischemic stunning of the myocardium in stress thallium-201 gated SPET myocardial perfusion imaging: segmental analysis of myocardial perfusion, wall motion and wall thickening changes.

Prolonged and persistent myocardial stunning has recently been demonstrated using technetium-99m sestamibi gated single-photon emission tomography (SPET) myocardial perfusion imaging post exercise or pharmacological stress test. In this study, we investigated the early postischemic transient myocardial stunning on early and delayed poststress thallium-201 gated SPET myocardial perfusion imaging using segmental wall motion (WM) and wall thickening (WT) analysis. A total of 1,680 segments from 84 patients' studies (53 men and 31 women, mean age 60 years) were evaluated on both early and delayed thallium-201 gated SPET treadmill exercise (59) or dobutamine stress (25) myocardial perfusion imaging. Semiquantitative analysis of perfusion, WM and WT in all segments was performed by two observers. Segments were classified according to changes in WM and WT between early and delayed images into normal, fixed abnormality, or improved abnormality (transient stunning), and were further classified according to changes in perfusion into normal, fixed defects, or ischemic. There were significant correlations between perfusion and WM, perfusion and WT, and WM and WT segmental scores on both early and delayed images. Transient stunning was seen significantly ( P < 0.001) more often in ischemic segments than were normal or fixed perfusion defects using WM (58%) and WT (50%) assessments. There was also a significant correlation between the severity of ischemia and transient stunning with either WM ( P < 0.05) or WT ( P < 0.005) evaluation. Segmental myocardial contractility assessment from gated SPET (201)Tl myocardial perfusion imaging using WM and WT was comparable, and results correlated well with the myocardial perfusion assessment. Early transient myocardial stunning was frequently observed in ischemic segments and was related to the severity of myocardial ischemia.

Postchemoembolization liver abscess: findings on hepatobiliary scintigraphy.

We describe a 41-year-old man with a 1-week history of nausea and vomiting 1 month after chemoembolization of a liver metastasis. The patient subsequently became febrile and developed right upper quadrant abdominal and midback pain. Findings of initial laboratory and imaging studies (a noncontrast computed tomographic [CT] scan and ultrasound) were not remarkable. Hepatobiliary scintigraphy, performed to rule out cholecystitis, revealed an abnormal area in the right lobe of the liver consistent with a focal bile leak into an abscess cavity. The patient was subsequently treated for liver abscess. In conclusion, hepatobiliary scintigraphy should be considered as a first-line test in the work-up of patients whenever a postchemoembolization complication is considered likely.