Association of use of proton pump inhibitors and H2 antagonists with stomach wall uptake in 99mTc-methoxy-isobutyl-isonitrile (MIBI) myocardial perfusion imaging.

BACKGROUND: Stomach wall uptake (SWU) of tracer in 99mTc-MIBI myocardial perfusion imaging (MPI) occasionally leads to imaging artifacts, thereby lowering the diagnostic accuracy. It is less-studied phenomenon for possible link with proton pump inhibitors (PPIs) intake. This prospective work looked for association of SWU with PPI intake and compared its incidence with H2 antagonists (H2A) users and patients not on either gastroprotective medication. METHODS: One hundred fifty-six patients undergoing one day stress/rest 99mTc-MIBI SPECT-MPI were distributed into four groups: control group (n = 48, not on any gastroprotective medication), PPI group (n = 47, on PPI treatment), H2A group (n = 19, on H2A therapy), and intervention group (N = 42, PPI discontinued for 3 days before MPI). Poststress planar images were analyzed for clinically relevant SWU. RESULTS: Clinically relevant SWU was seen in 36% of PPI group patients compared to 8% in the control group, 10.5% in the H2A group, and 9.5% in the intervention group, respectively, with statistically significant difference. Only 1/40 patients undergoing exercise stress showed clinically relevant SWU compared to 26/116 patients undergoing adenosine stress (P = .020). CONCLUSION: Patients on PPIs scheduled for vasodilator stress MPI may discontinue PPIs for 3 days, or replace with H2A to reduce the incidence of clinically relevant SWU associated with PPI therapy.

18F-FDG PET/CT in Diagnostic and Prognostic Evaluation of Patients With Suspected Recurrence of Chondrosarcoma.

PURPOSE: The aim of the study was to analyze the diagnostic and prognostic utility of F-FDG PET/CT to predict the disease-specific survival (DSS) with FDG uptake and tumor grade in recurrent chondrosarcoma. METHODS: Retrospective analysis of FDG PET/CT findings in 31 previously treated patients (46 studies) with mean follow-up period of 40.7 ± 23.9 months (range, 3-77 months) from the date of first PET/CT study was done. Kaplan-Meier DSS analysis was made with respect to tumor grade, FDG uptake at the recurrent primary sites, and a combination of grade and FDG uptake as parameters. RESULTS: Recurrence (local and distant) was shown in 28 (60.8%) of 46 FDG PET/CT studies with sensitivity and specificity of 88.9% and 78.9%, respectively. The median SUVmax at the recurrent primary sites differed significantly (P = 0.008) among 3 tumor grade groups, with higher median SUVmax in higher grades. There was significant difference in median SUVmax among different grade groups except between grade II and grade III. Recurrent primary site SUVmax cutoff at 6.15 derived from the receiver operating characteristic curve yielded significant difference (P < 0.001) in mean DSS time. Significant difference in survival was noted between 3 different tumor grade groups (P = 0.016). The combination of SUVmax and grade improved the survival prediction than with grade alone. CONCLUSIONS: In recurrent chondrosarcoma, the recurrent primary site FDG uptake and grade were found to be reliable prognostic factors with respect to DSS. PET/CT in recurrence setting has the potential to predict tumor grade and survival and may assist in clinical management.

Comparative Effectiveness of Ultrasonography, 99mTc-Sestamibi, and 18F-Fluorocholine PET/CT in Detecting Parathyroid Adenomas in Patients With Primary Hyperparathyroidism.

PURPOSE: Accurate preoperative localization of parathyroid lesion(s) is crucial for successful surgical management of primary hyperparathyroidism (PHPT). This study was conducted to compare the effectiveness of ultrasonography (USG) of the neck, Tc-sestamibi (MIBI) imaging with or without SPECT/CT, and F-fluorocholine (FCH) PET/CT imaging in the preoperative localization of parathyroid lesions in patients with PHPT. METHODS: Fifty-four consecutive patients with PHPT were included in this prospective study who underwent preoperative localization of the parathyroid lesion(s) using 3 diagnostic modalities followed by surgery. The sensitivity, positive predictive value, and accuracy of the 3 imaging procedures to accurately detect abnormal parathyroid glands were determined using histopathology as criterion standard with postoperative biochemical response confirmation. RESULTS: F-fluorocholine PET/CT detected 52 of 54 patients and 52 of 56 lesions with histopathologically proven parathyroid adenomas on patient-based and lesion-based analysis, respectively. Preoperative USG, MIBI, and FCH PET/CT localized abnormal parathyroid gland(s) in 39 (72.2%), 43 (79.6%), and 54 (100%) patients, respectively. The sensitivity and positive predictive value were 69.3% and 87.1% for USG, 80.7% and 97.6% for MIBI, and 100% and 96.3% for FCH PET/CT. The accuracy was 62.9%, 79.6%, and 96.3% for USG, MIBI, and FCH PET/CT, respectively, in patient-wise analysis. In 6 patients with ectopic lesions, FCH PET/CT demonstrated higher sensitivity and accuracy than MIBI and USG (100% vs 66.6% and 16.7%, respectively). CONCLUSIONS: Among the 3 imaging techniques tested simultaneously, FCH PET/CT was superior for accurate preoperative localization of parathyroid adenomas, especially for ectopic or small parathyroid lesions.

Real-time intraprocedural 18F-FDG PET/CT-guided biopsy using automated robopsy arm (ARA) in the diagnostic evaluation of thoracic lesions with prior inconclusive biopsy results: initial experience from a tertiary health care centre.

OBJECTIVE: The aim of this study was to assess the feasibility and appraise the diagnostic utility of real time 18F-FDG PET/CT-guided biopsy under automated robopsy arm (ARA) guidance for the evaluation of thoracic lesions with prior inconclusive biopsy results. METHODS: PET/CT-guided biopsy of thoracic lesions was performed in patients who had at least one previous inconclusive biopsy. A total of 25 patients (male:female-18 males, 7 females; age: range, 13-75; mean, 53.7) were included in this study. All these patients underwent percutaneous needle biopsies under real-time PET/CT guidance using ARA (ROBIO-EX, Perfint healthcare Pvt Ltd, Chennai, India) needle navigation technique. Histopathology and clinical follow-up results were reviewed for assessing the accuracy of procedures. RESULTS: Adequate representative tissue sample could be retrieved in all the patients. No major procedure-related complications were encountered in any patient. Of the 25 procedures, 21 lesions were positive for malignancy and benign findings were observed in the other 4 lesions on histopathology. None of the patients required further biopsy in arriving at a final diagnosis. Overall diagnostic yield of the procedure was 100%. CONCLUSION: Real time 18F-FDG PET/CT guidance for percutaneous biopsies of lung and mediastinal lesions is a feasible technique with potential utility in patients with previous inconclusive biopsy results. Advances in knowledge: 18F-FDG PET/CT guidance reduces the sampling errors by specifically targeting areas of viability and avoiding necrosis/atelectasis. A navigational tool like ARA is thought to help in accurately targeting these areas.

Potential Adjunctive Role of Radiosynovectomy in Primary Synovial Osteochondromatosis of the Knee: A Case Report.

Primary synovial osteochondromatosis (PSOC) is a rare but clinically significant cause of morbidity especially in the male population. Surgery is the primary treatment of choice, but the recurrence rate is reported to be high. Moreover, the presence of widespread loose bodies makes it a cumbersome procedure. The complete removal of the disease is tough at times and results in early recurrence. Radiosynovectomy is an established technique for treating various joint arthropathies. The role of radiosynovectomy in case of PSOC has not yet been explored. This case report described the case of a young male with PSOC of the knee joint who was treated with radiosynovectomy for pain relief. The patient reported complete relief from the pain along with significant improvement in joint mobility. The post-therapy three-phase bone scan also validated the reduction in joint inflammation. The patient was taken for surgical removal of the redundant loose bodies after a significant improvement in the pain and reduction in inflammation. Post-therapy radiation fibrosis of the synovium also helped in the en bloc removal of the disease. The role of radiosynovectomy in PSOC needs to be further explored concerning its potential role as an adjuvant to surgical procedures.

Unsuspected Active Ulcerative Colitis in a Patient With Dermatomyositis: A Rare Association Detected on 18F-FDG PET/CT During the Search for an Occult Malignancy.

Dermatomyositis is an inflammatory myopathy with the characteristic features of skin rash and myopathy. We here present a known case of dermatomyositis evaluated with 18F-FDG PET/CT for the presence of any occult malignancy. The scan was negative for the presence of any malignancy. However, it revealed multiple intensely FDG avid colonic strictures that were later proven on colonoscopic biopsy to be ulcerative colitis. Also, a well-known association of bilateral sacroilitis was simultaneously demonstrated on the scan. The present case demonstrates that 18F-FDG PET/CT imaging can serve as a one-stop shop imaging modality in dermatomyositis by facilitating detection of occult primary if any and by providing insight into other rare systemic associations.

Adenosine Stress Induced Left Bundle Branch Block During Technetium-99m Tetrofosmin Myocardial Perfusion Imaging.

The occurrence of left bundle branch block (LBBB) in electrocardiogram during exercise testing is a relatively rare finding. The incidence of LBBB during exercise testing ranges from 0.5% to 1.1%. The mechanism of exercise-induced LBBB (EI-LBBB) is poorly understood, but ischemia is a proposed etiology. Stress myocardial perfusion imaging (MPI) can be useful in patients with EI-LBBB to rule out coronary artery disease. Adenosine vasodilator stress is the preferred mode of stress in patients with LBBB for performing stress-MPI. Here we present an interesting case of adenosine-induced LBBB during stress-MPI in a 67-year-old female patient with normal coronary angiography.

68Ga-DOTATATE PET/CT in Primary Hepatic Neuroendocrine Tumor.

Primary neuroendocrine tumors of the liver are a diagnostic challenge. We present a rare case of primary hepatic neuroendocrine tumor in which Ga-DOTATATE PET/CT imaging played an important role in the diagnosis and follow-up.

Contrast-enhanced fluorodeoxyglucose positron emission tomography/contrast-enhanced computed tomography in mediastinal T-cell lymphoma with superior vena cava syndrome.

Positron emission tomography-computed tomography (PET/CT) is a routine investigation for the staging of lymphomas. Contrast-enhanced computed tomography is mandatory whenever parenchymal lesions, especially in the liver and spleen are suspected. We report a rare case of primary mediastinal T-cell lymphoma evaluated with contrast-enhanced PET/CT that showed features of superior vena cava syndrome.

Substantial Increase in Myocardial FDG Uptake on Interim PET/CT May Be an Early Sign of Adriamycin-Induced Cardiotoxicity.

Cumulative cardiotoxicity is a well-established adverse effect of Adriamycin therapy. Although dose dependent, cardiotoxicity has been recently reported to occur even at lower doses than usually proposed. Conventional imaging detection and/or clinical manifestation of the deterioration in cardiac function occur late in the process; thus, it is desirable to have noninvasive markers to detect toxicity at an early stage. Several biochemical markers including troponin and atrial natriuretic peptide were explored for this purpose. The present case depicts that a significant increase in myocardial FDG uptake on posttherapy PET/CT can be a potential imaging biomarker of Adriamycin-induced cardiotoxicity.

18F-FDG PET/CT imaging and PET-guided biopsy in evaluation and treatment decision in adrenal histoplasmosis.

Histoplasmosis is a rare opportunistic fungal infection. It is commonly seen in immunocompromised individuals from endemic areas. Adrenal glands are frequently involved in the disseminated disease. Here, we present the case of a retropositive patient with constitutional symptoms, where whole-body positron emission tomography/CT scan revealed intense 18F-fludeoxyglucose uptake in bulky adrenal glands, and subsequent positron emission tomography-guided biopsy helped in establishing the diagnosis of adrenal histoplasmosis.