Modified Hepatobiliary Scintigraphy for the Diagnosis of Bile Reflux in One-Anastomosis Gastric Bypass Surgery: a Prospective Multicenter Study.

PURPOSE: One-anastomosis gastric bypass (OAGB) is a relatively simple surgical procedure for those afflicted with severe obesity. Studies reported symptomatic biliary reflux gastritis and esophagitis as predominant complications. Hepatobiliary scintigraphy (HIDA) is the least invasive test for the diagnosis of bile reflux, with good sensitivity, patient tolerability, and reproducibility. The aim of this study was to define an optimized HIDA scintigraphy protocol for demonstrating bile reflux in post-OAGB patients. MATERIAL AND METHODS: We conducted a prospective multicenter study. Patients after OAGB with dyspeptic complaints were included. All patients underwent HIDA scan with a dedicated protocol for demonstrating bile reflux; prevalence and severity were reported. RESULTS: Nineteen patients were included, 18 females and one male, with mean age of 41.8 years and mean time of 22.4 months from operation to the scan. Bile reflux into the gastric pouch was documented in 11 patients (53%). Reflux to the stomach pouch was severe in three patients (27%), moderate in two patients (18%), and mild in six patients (55%). Bile reflux into the esophagus was documented in four patients (21%), severe reflux in one patient (25%), and mild in the other three (75%). A correlation was found between complaints of vomiting, heartburn and regurgitation, and findings of esophagitis on gastroscopy in patients with vs. without reflux. CONCLUSIONS: The tailored HIDA scan protocol detected bile reflux in more than half of the post-OAGB patients included in the study, with a high diagnostic sensitivity.

Vascular Graft Infection Imaging.

Vascular graft infection is a rare, life threatening complication of vascular repair with synthetic or native material. The pathogenesis, causative microorganisms and clinical manifestations vary according to graft's location and time duration since surgery. The diagnosis of graft infection is challenging since there is no single "gold standard" test and diagnosis is based on clinical and radiological criteria. Early and accurate diagnosis are essential for patient management and prevention of further complications. The first-choice imaging modality is computed tomography angiography (CTA) that can demonstrate typical signs of graft infection but has limited sensitivity and specificity, especially in early and low-grade infections. Nuclear medicine imaging methods, including labeled white blood cell scintigraphy and FDG PET/CT demonstrate improved diagnostic accuracy and play a pivotal role in the diagnosis of vascular graft infection. The different radiologic and the nuclear medicine imaging techniques, their advantages and limitations, and the recent guidelines detailing their use are reviewed.

A Founder Mutation in EHD1 Presents with Tubular Proteinuria and Deafness.

BACKGROUND: The endocytic reabsorption of proteins in the proximal tubule requires a complex machinery and defects can lead to tubular proteinuria. The precise mechanisms of endocytosis and processing of receptors and cargo are incompletely understood. EHD1 belongs to a family of proteins presumably involved in the scission of intracellular vesicles and in ciliogenesis. However, the relevance of EHD1 in human tissues, in particular in the kidney, was unknown. METHODS: Genetic techniques were used in patients with tubular proteinuria and deafness to identify the disease-causing gene. Diagnostic and functional studies were performed in patients and disease models to investigate the pathophysiology. RESULTS: We identified six individuals (5-33 years) with proteinuria and a high-frequency hearing deficit associated with the homozygous missense variant c.1192C>T (p.R398W) in EHD1. Proteinuria (0.7-2.1 g/d) consisted predominantly of low molecular weight proteins, reflecting impaired renal proximal tubular endocytosis of filtered proteins. Ehd1 knockout and Ehd1R398W/R398W knockin mice also showed a high-frequency hearing deficit and impaired receptor-mediated endocytosis in proximal tubules, and a zebrafish model showed impaired ability to reabsorb low molecular weight dextran. Interestingly, ciliogenesis appeared unaffected in patients and mouse models. In silico structural analysis predicted a destabilizing effect of the R398W variant and possible inference with nucleotide binding leading to impaired EHD1 oligomerization and membrane remodeling ability. CONCLUSIONS: A homozygous missense variant of EHD1 causes a previously unrecognized autosomal recessive disorder characterized by sensorineural deafness and tubular proteinuria. Recessive EHD1 variants should be considered in individuals with hearing impairment, especially if tubular proteinuria is noted.

[THE ROLE OF NUCLEAR MEDICINE IN THE WORKUP OF CHRONIC THROMBOEMBOLIC PULMONARY HYPERTENSION (CTEPH) IN A PATIENT SUFFERING FROM SYNCOPE AND SHORTNESS OF BREATH].

INTRODUCTION: In patients diagnosed with pulmonary hypertension (PH), V/Q lung scintigraphy performed in Nuclear Medicine departments can demonstrate pulmonary embolisms and diagnose chronic thromboembolic pulmonary hypertension (CTEPH). Lung scintigraphy has higher sensitivity and specificity for CTEPH in comparison to other imaging methods, and is considered to be the method of choice in the workup of patients with unexplained PH. In the case presented, lung scintigraphy performed at two time points in a patient with PH demonstrated chronic bilateral pulmonary embolisms and aided in the diagnosis of CTEPH.

PET/CT Imaging in Soft Tissue Infection and Inflammation-An Update.

Nuclear medicine procedures, including Ga-67 and labeled leucocyte SPECT/CT as well as PET/CT using 18F-FDG and recently Ga-68 tracers, have found extensive applications in the assessment of infectious and inflammatory processes in general and in soft tissues in particular. Recent published data focus on summarizing the available imaging information with the purpose of providing the referring clinicians with optimized evidence based results. Guidelines and/or recommendations of clinical societies have incorporated nuclear medicine tests (using both labeled leucocytes and FDG) in their suggested work-up for evaluation of infective endocarditis and in certain patients with suspected vascular graft infections. Joint guidelines of the European and American nuclear medicine societies include fever of unknown origin, sarcoidosis, and vasculitis among the major clinical indications that will benefit from nuclear medicine procedures, specifically from FDG PET/CT. Limitations and pitfalls for the use of radiotracers in assessment of infection and inflammation can be related to patient conditions (eg, diabetes mellitus), or to the biodistribution of a specific radiopharmaceutical. Limited presently available data on the use of functional and/or metabolic monitoring of response to infectious and inflammatory processes to treatment and with respect to the effect of drugs such as antibiotics and glucocorticoids on the imaging patterns of these patients need further confirmation.

Head-to-Head Prospective Comparison of Quantitative Lung Scintigraphy and Segment Counting in Predicting Pulmonary Function in Lung Cancer Patients Undergoing Video-Assisted Thoracoscopic Lobectomy.

Prediction of postoperative pulmonary function in lung cancer patients before tumor resection is essential for patient selection for surgery and is conventionally done with a nonimaging segment counting method (SC) or 2-dimensional planar lung perfusion scintigraphy (PS). The purpose of this study was to compare quantitative analysis of PS to SPECT/CT and to estimate the accuracy of SC, PS, and SPECT/CT in predicting postoperative pulmonary function in patients undergoing lobectomy. Methods: Seventy-five non-small cell lung cancer patients planned for lobectomy were prospectively enrolled (68% male; average age, 68.1 ± 8 y). All patients completed tests of preoperative forced expiratory volume capacity in 1 s (FEV1) and diffusing capacity of the lungs for carbon monoxide (DLCO), as well as 99mTc-macroaggregated albumin PS and SPECT/CT quantification. A subgroup of 60 patients underwent video-assisted thoracoscopic lobectomy and measurement of postoperative FEV1 and DLCO. Relative uptake of the lung lobes estimated by PS and SPECT/CT was compared. Predicted postoperative FEV1 and DLCO were derived from SC, PS, and SPECT/CT. Prediction results were compared between the different methods and the true postoperative measurements in patients who underwent lobectomy. Results: Relative uptake measurements differed significantly between PS and SPECT/CT in right lung lobes, with a mean difference of -8.2 ± 3.8, 18.0 ± 5.0, and -11.5 ± 6.1 for right upper, middle, and lower lobes, respectively (P < 0.001). The differences between the methods in the left lung lobes were minor, with a mean difference of -0.4 ± 4.4 (P > 0.05) and -2.0 ± 4.0 (P < 0.001) for left upper and lower lobes, respectively. No significant difference and a strong correlation (R = 0.6-0.76, P < 0.001) were found between predicted postoperative lung function values according to SC, PS, SPECT/CT, and the actual postoperative FEV1 and DLCO. Conclusion: Although lobar quantification parameters differed significantly between PS and SPECT/CT, no significant differences were found between the predicted postoperative lung function results derived from these methods and the actual postoperative results. The additional time and effort of SPECT/CT quantification may not have an added value in patient selection for surgery. SPECT/CT may be advantageous in patients planned for right lobectomy, but further research is warranted.

Diabetic Foot Infection: The Role of PET/CT Imaging.

Osteomyelitis in the diabetic foot can be difficult to diagnose and has serious consequences. Although 2-deoxy-2-[18F]-fluoro-D-glucose (FDG) positron emission tomography (PET) was traditionally used in oncology, it is emerging as a useful method in inflammatory and infectious entities. In this chapter, original research articles, meta-analyses, and reviews on the performance of FDG PET in diagnosing osteomyelitis in the diabetic foot will be discussed. In addition, PET available data in comparison to different imaging methods, different analysis methods, and impact of other co-existing conditions such as hyperglycemia, and long-term antibiotic treatment on the performance of FDG PET will be reviewed. Studies published in the last two decades showed variable performance of FDG PET in the assessment of diabetic foot infection with a relatively high specificity (67-93%) but a wide range of sensitivity (29-100%). More recent studies showed better sensitivity, probably due to improved imaging technology and analysis methods and use of hybrid imaging with positron emission tomography/ computed tomography (PET/CT). FDG PET/CT has several advantages compared to other anatomical and functional imaging methods, including short acquisition time, high resolution, low radiation dose, and better tolerability. Further research is required to establish its role in the clinical practice.