Faculty Bibliography

This article discusses possible roles for emerging novel positron emission tomography (PET) radiotracers for diagnosis and follow-up of lymphomas. Novel imaging probes are being developed to fulfill the need of a more specific radiopharmaceutical to target subcomponents of tumor microenvironment to individualize management approaches. Noninvasive molecular imaging probes are being developed to revolutionize characterization of tumor biology and response to therapy in more specific ways for the host, tumor microenvironment, and therapeutic regimens. The new clinical PET probes seem promising in fostering clinical gains that would lead to better survival outcomes, although further studies are warranted to prove a role in the management of lymphomas.

Although the current literature is limited, available data suggest that (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) imaging improves the evaluation of patients with recurrent pancreatic carcinoma and cholangiocarcinoma. There is evidence that PET/CT is particularly useful in the setting of elevated tumor markers and negative or equivocal CT findings. This article reviews the nature of these carcinomas in the post-therapy setting and describes the strengths and limitations of PET/CT when used for monitoring recurrence.

To reduce doxorubicin, bleomycin, vinblastine and dacarbazine toxicity, the Cancer and Leukemia Group B conducted a phase 2 trial of doxorubicin, vinblastine, and gemcitabine for newly diagnosed, nonbulky stages I and II Hodgkin lymphoma. Ninety-nine assessable patients received 6 cycles of doxorubicin 25 mg/m(2), vinblastine 6 mg/m(2), and gemcitabine 800 mg/m(2) (1000 mg/m(2) in first 6) on days 1 and 15 every 28 days. Computed tomography (CT) and positron emission tomography (PET) were performed before and after 2 and 6 cycles. Complete remission (CR)/CR unconfirmed was achieved in 72 of 99 patients (72.7%) and partial remission in 24 of 99 patients (24.2%). The CR rate was 81% when using PET criteria. Two patients have died of Hodgkin lymphoma progression. Median follow-up for nonprogressing patients is 3.3 years. The progression-free survival (PFS) at 3 years was 77% (95% confidence interval, 68%-84%). The relapse rate was less than 10% for patients with favorable prognostic factors. The 2-year PFS for cycle 2 PET-negative and -positive patients was 88% and 54%, respectively (P = .0009), compared with 89% and 27% for cycle 6 PET-negative and -positive patients (P = .0001). Although the CR rate and PFS were lower than anticipated, patients with favorable prognostic features had a low rate of relapse. Cycle 2 PET and cycle 6 PET were predictive of PFS.

OBJECTIVES/OBJECTIVE:  The precise role of positron emission tomography (PET/CT) for predicting relapse/progression in multiple myeloma remains uncertain. We compared the predictive values of PET/CT, concurrent laboratory testing (labs), and their combination in prediction of 12-month progression, as determined by current International Myeloma Working Group (IMWG) criteria. METHODS:  PET/CT and labs (serum chemistry, β2-microglobulin, immunofixation, bone marrow biopsy, serum free light chains) were reviewed, and date of relapse/progression was determined by IMWG criteria. RESULTS:  The median time from therapy to PET/CT imaging was 12.0 months (1.0-110) and median time to progression (TTP) was 29.8 months (1.6-130+). Overall survival and survival-without-progression at last follow-up were 84% and 49%, respectively. Sensitivity of PET/CT for predicting relapse/progression was lower than that of labs (0.67 vs. 0.89, ns), but PET/CT was more specific (0.89 vs. 0.79, ns). When labs and PET/CT data were combined, a positive result for either test was 89% sensitive and a positive result for both tests was 100% specific for predicting 12-month progression of disease. Kaplan-Meier analysis showed significantly greater TTP for those with a negative vs. positive PET/CT (P = 0.0005), negative vs. positive labs (P < 0.0001), and both tests negative vs. both tests positive (P < 0.0001). CONCLUSIONS:  Combining PET/CT with laboratory data improves the accuracy of prediction of relapse/progression within 12 months compared with each test alone. Thus, integration of PET/CT into myeloma follow-up is recommended, and the impact of this approach on management should be explored.

Ovarian cancer is the fifth leading cause of cancer death among women in the United States and has a high likelihood of recurrence despite aggressive treatment strategies. Detection and exact localization of recurrent lesions are critical for guiding management and determining the proper therapeutic approach, which may prolong survival. Because of its high sensitivity and specificity compared with those of conventional techniques such as computed tomography (CT) and magnetic resonance (MR) imaging, fluorine 18 fluorodeoxyglucose positron emission tomography (PET) combined with CT is useful for detection of recurrent or residual ovarian cancer and for monitoring response to therapy. However, PET/CT may yield false-negative results in patients with small, necrotic, mucinous, cystic, or low-grade tumors. In addition, in the posttherapy setting, inflammatory and infectious processes may lead to false-positive PET/CT results. Despite these drawbacks, PET/CT is superior to CT and MR imaging for depiction of recurrent disease.

BACKGROUND:The differentiation of the nature of a fluid collection as a complication of kidney transplantation is important for management and treatment planning. Early and delayed radionuclide renography can play an important role in the evaluation of a urine leak. However, it is sometimes limited in the evaluation of the exact location and extent of a urine leak. CASE PRESENTATION/METHODS:A 71-year-old male who had sudden anuria, scrotal swelling and elevated creatinine level after cadaveric renal transplantation performed Tc-99 m MAG3 renography to evaluate the renal function, followed by an ultrasound which was unremarkable. An extensive urine leak was evident on the planar images. However, an exact location of the urine leak was unknown. Accompanying SPECT/CT images confirmed a urine leak extending from the lower aspect of the transplant kidney to the floor of the pelvic cavity, presacral region and the scrotum via right inguinal canal as well as to the right abdominal wall. CONCLUSIONS:Renal scintigraphy is very useful to detect a urine leak after renal transplantation. However, planar imaging is sometimes limited in evaluating the anatomical location and extent of a urine leak accurately. In that case accompanying SPECT/CT images are very helpful and valuable to evaluate the anatomical relationships exactly.

The prognosis of invasive cervical cancer is based on the stage, size, and histologic grade of the primary tumor and the status of the lymph nodes. Assessment of disease stage is essential in determining proper management in individual cases. In the posttherapy setting, the timely detection of recurrence is essential for guiding management and may lead to increased survival. However, the official clinical staging system of the International Federation of Gynecology and Obstetrics has inherent flaws that may lead to inaccurate staging and improper management. Combined positron emission tomography (PET)/computed tomography (CT) represents a major technologic advance, consisting of two integrated complementary modalities whose combined strength tends to overcome their respective weaknesses. PET/CT has higher sensitivity and specificity than do conventional anatomic modalities and is valuable in determining the extent of disease and detecting recurrent or residual tumor. The combination of 2-[fluorine-18]fluoro-2-deoxy-d-glucose PET with intravenous contrast material-enhanced high-resolution CT has proved useful for avoiding the interpretative weaknesses associated with either modality alone and in increasing the accuracy of staging or restaging. Nonetheless, accurate PET/CT interpretation requires a knowledge of the characteristics of disease spread or recurrence and an awareness of various imaging pitfalls if false interpretations are to be avoided.

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.

Schneiderian papillomas are benign tumors of the nasal cavity and paranasal sinuses often asymptomatic in their early stages. We report a case of a maxillary sinus oncocytic schneiderian papilloma first detected by positron-emission tomography by using fluorodeoxyglucose (FDG). Schneiderian papillomas demonstrate increased FDG uptake, similar to that of other oncocytic tumors, making it important for otolaryngologists and radiologists to realize that high uptake of FDG does not necessarily indicate a malignant lesion.