Chronic fatigue syndrome: illness severity, sedentary lifestyle, blood volume and evidence of diminished cardiac function.

The study examined whether deficits in cardiac output and blood volume in a CFS (chronic fatigue syndrome) cohort were present and linked to illness severity and sedentary lifestyle. Follow-up analyses assessed whether differences in cardiac output levels between CFS and control groups were corrected by controlling for cardiac contractility and TBV (total blood volume). The 146 participants were subdivided into two CFS groups based on symptom severity data, severe (n=30) and non-severe (n=26), and two healthy non-CFS control groups based on physical activity, sedentary (n=58) and non-sedentary (n=32). Controls were matched to CFS participants using age, gender, ethnicity and body mass. Echocardiographic measures indicated that the severe CFS participants had 10.2% lower cardiac volume (i.e. stroke index and end-diastolic volume) and 25.1% lower contractility (velocity of circumferential shortening corrected by heart rate) than the control groups. Dual tag blood volume assessments indicated that the CFS groups had lower TBV, PV (plasma volume) and RBCV (red blood cell volume) than control groups. Of the CFS subjects with a TBV deficit (i.e. > or = 8% below ideal levels), the mean+/-S.D. percentage deficit in TBV, PV and RBCV were -15.4+/-4.0, -13.2+/-5.0 and -19.1+/-6.3% respectively. Lower cardiac volume levels in CFS were substantially corrected by controlling for prevailing TBV deficits, but were not affected by controlling for cardiac contractility levels. Analyses indicated that the TBV deficit explained 91-94% of the group differences in cardiac volume indices. Group differences in cardiac structure were offsetting and, hence, no differences emerged for left ventricular mass index. Therefore the findings indicate that lower cardiac volume levels, displayed primarily by subjects with severe CFS, were not linked to diminished cardiac contractility levels, but were probably a consequence of a co-morbid hypovolaemic condition. Further study is needed to address the extent to which the cardiac and blood volume alterations in CFS have physiological and clinical significance.

Analysis of the effects of injecting drug use and HIV-1 infection on 18F-FDG PET brain metabolism.

UNLABELLED: Injecting drug use (IDU) is a major risk factor for contracting HIV-1 infection. Both HIV and IDU are neurotoxic, and their coexistence may lead to increased dysfunction of brain metabolic processes. The objective of this research was to investigate the effects of HIV-1 infection and IDU on (18)F-FDG PET brain metabolism. METHODS: (18)F-FDG PET brain imaging, with a standard clinical protocol, was performed on 59 subjects who belonged to 3 groups: HIV-positive/IDU-positive (n = 17), HIV-negative/IDU-positive (n = 13), and HIV-negative/IDU-negative controls (n = 29). A voxel-based analysis of the (18)F-FDG PET brain images was performed using statistical parametric mapping. The images were spatially normalized to a standard (18)F-FDG template, proportionally scaled to compensate for count differences, and then appropriately smoothed. Statistical 2-sample t tests were performed to determine regional metabolic distribution differences in the 3 groups. RESULTS: Diffuse hypermetabolism in the subcortical and deep white matter, the basal ganglia, and the thalami was observed in HIV-1 infection. IDU resulted in increased brainstem metabolism and decreased activity in cortical structures including bilateral medial frontal lobes and the right inferior frontal and temporal cortices. The cortical hypometabolism was more extensive in HIV-1-infected subjects, involving the left temporoparietal and right parietal cortices and bilateral medial frontal lobes. CONCLUSION: Voxel-based analysis of (18)F-FDG PET brain images demonstrated statistically significant differences in regional metabolism for the 3 studied groups. It also showed that HIV-1 infection may have a synergistic effect with IDU, resulting in more extensive cortical hypometabolism. Correlation of these findings with other quantitative approaches and neurocognitive functioning is warranted.

Hepatobiliary scintigraphy in liver transplant patients: the "blind end sign" and its differentiation from bile leak.

PURPOSE: Hepatobiliary scintigraphy is commonly performed on liver transplant patients to exclude biliary complications such as obstruction or leak. Biliary reconstruction in these patients is performed using either a direct duct-to-duct anastomosis (choledochocholedochostomy) or a biliary-enteric anastomosis (Roux-en-Y hepaticojejunostomy). The authors have observed a finding in scans performed on the latter group of patients that often simulates a bile leak. They postulate this finding to represent retention of activity in the blind end of the Roux limb (the "blind end sign"). The purpose of this study was to determine characteristics of this blind end activity, which may help differentiate it from true bile leaks. METHODS: Two nuclear medicine physicians reviewed 36 Tc-99m mebrofenin hepatobiliary scans (31 patients). Biliary reconstruction was performed in 25 patients with a Roux-en-Y hepaticojejunostomy, and in 6 patients with a choledochocholedochostomy. Each scan was evaluated regarding whether there was focal, persistent retention of activity in the anastomotic region, and, if so, various features of the activity were noted. Activity was concluded to represent a true bile leak based on subsequent surgical confirmation, and if there was no such confirmation, the activity was concluded to represent blind end retention in patients with Roux-en-Y hepaticojejunostomies. RESULTS: There were 8 total examples of blind end activity and 3 examples of bile leak activity. Useful discriminators between the 2 types of activity included the following: fluctuation in size and/or intensity with time (8 of 8 blind end cases vs. 0 of 3 bile leak cases); size comparable with bowel (8 of 8 vs. 1 of 3); tubular (4 of 8 vs. 0 of 3), round (4 of 8 vs. 1 of 3), or irregular (0 of 8 vs. 2 of 3) shape; and movement into bowel (3 of 8 vs. 0 of 3). Delayed imaging was performed in 3 cases at 1.5 hours, but was only conclusive in 1 case in which diffuse extravasation was seen consistent with bile leak. CONCLUSION: Retention of activity in the blind end of the Roux limb in patients with Roux-en-Y hepaticojejunostomies may simulate bile leak, but certain typical features, as well as delayed imaging, may aid in distinguishing the two.

Renal scintigraphy in the acute care setting.

Renal scintigraphy is a powerful imaging method that provides both functional and anatomic information, which is particularly useful in the acute care setting. In our institution, for the past 2 decades, we have used a 25-minute renal diuretic protocol, technetium-99m ((99m)Tc) mercaptoacetyltriglycine with simultaneous intravenous injection of furosemide, for all ages and indications, including both native and transplant kidneys. As such, this protocol has been widely used in the workup of acutely ill patients. In this setting, there are common clinical entities which affect patients with native and transplant kidneys. In adult patients with native kidneys one of the most frequent reasons for emergency room visits is renal colic due to urolithiasis. Although unenhanced computed tomography is useful to assess the anatomy in cases of renal colic, it does not provide functional information. Time zero furosemide renal scintigraphy can do both and we have shown that it can effectively stratify patients with renal colic. To this end, 4 characteristic patterns of scintirenography have been identified, standardized, and consistently applied: no obstruction, partial obstruction (mild vs high grade), complete obstruction, and stunned (postdecompressed) kidney. With the extensive use of this protocol over the past 2 decades, a pattern of "regional parenchymal dysfunction" indicative of acute pyelonephritis has also been delineated. This information has proved to be useful for patients presenting with urinary tract infection and suspected pyelonephritis, as well as for patients who were referred for workup of renal colic but were found to have acute pyelonephritis instead. In instances of abdominal trauma, renal scintigraphy is uniquely suited to identify urine leaks. This is also true in cases of suspected leak following renal transplant or from other iatrogenic/postsurgical causes. Patients presenting with acute renal failure can be evaluated with renal scintigraphy. A scintigraphic pattern of "relative preservation of flow as compared to function" has been identified as indicative of acute tubular necrosis, which is distinct from other potential causes of acute renal failure, such as nephrotoxicity and in the case of renal transplants, rejection.

F-18 FDG PET positive hilar and mediastinal lymphadenopathy mimicking metastatic disease in a melanoma patient treated with interferon-alpha-2b.

A 49-year-old man with a history of recurrent melanoma in the parotid was treated with parotidectomy, external beam radiation, and high-dose interferon-alpha-2b. Combined F-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) performed for restaging demonstrated multiple bilateral hilar and mediastinal hypermetabolic foci corresponding to hilar and mediastinal lymphadenopathy. Cytologic specimens obtained by bronchoscopy were negative for malignancy, revealing reactive lymph nodes. Subsequent FDG PET/CT showed regression of the findings. Awareness of possible interferon-associated reaction in melanoma patients who undergo FDG PET is important to avoid pitfalls in the interpretation.

Contemporary Encephalitis Lethargica: phenotype, laboratory findings and treatment outcomes.

BACKGROUND: Encephalitis lethargica (EL) is a CNS disorder that manifests with lethargy sleep cycle disturbances, extrapyramidal symptomatology, neuropsychiatric manifestations, ocular features and cardio-respiratory abnormalities. Although there have been no reported outbreaks of EL recently, a number of reports show that cases of EL are still encountered regularly. Against this background we conducted a study aiming to elucidate the clinical characteristics, describe laboratory/ neuroimaging findings (MRI, PET) and present treatment options and outcomes in sporadic EL. METHODS: Patients were diagnosed over a period of 3 years using proposed diagnostic criteria. Extensive laboratory and imaging tests were performed for exclusion of other causes. Anti-neuronal antibodies against human basal ganglia were detected with western immunoblotting and (18)F-FDG PET imaging was performed. Selected cases were videotaped. RESULTS: Our patients (M/F: 5/3) ranged from 2-28 years (mean 9.3 +/- 9.5). Encephalopathy, sleep disturbances and extrapyramidal symptoms were present in all cases. Laboratory investigations revealed CSF leukocytosis in 5/8 patients and anti-BG Ab in 4/7 patients. MRIs revealed structural abnormalities in 7/8 cases. (18)F-FDG PET showed basal ganglionic hypermetabolism in 4/7 patients. Treatment approaches included immunomodulating and symptomatic therapies. We report no mortality from EL in our series. CONCLUSIONS: There seems to be little doubt that cases of EL still occur. Diagnosis may be based on clinical suspicion and laboratory/imaging tests may lead to early initiation of immunomodulating and supporting therapies. We suggest that in addition to anti-BG Abs FDG PET should be considered as a diagnostic tool for EL.

A renal protocol for all ages and all indications: mercapto-acetyl-triglycine (MAG3) with simultaneous injection of furosemide (MAG3-F0): a 17-year experience.

Current clinical requirements mandate the existence of a renal diuretic protocol, which is fast and easy, applicable in all ages and for all indications, convenient for both the patient and the technologist, and provides diagnostic as well as prognostic information. Seventeen years ago a 25-minute protocol, after oral hydration, with no bladder catheterization, and simultaneous injection of mercapto-acetyl-triglycine (MAG(3)) and furosemide (MAG(3)-F(0)), was initiated. It initially was used for the evaluation of drainage and emerged as a protocol to also evaluate the renal parenchyma. Results of this protocol have been published individually, per clinical application. MAG(3)-F(0) was instrumental in the evaluation and prognosis of congenital disorders. For obstruction, in the newborn, an increasing renogram mandates intervention, whereas a downsloping one predicts spontaneous resolution. In children or adults, preoperatively or postoperatively, when the cortex was visualized and drained normally, there was no obstruction, even if urine was retained within a dilated collecting system or an extrarenal pelvis. For diseases of the renal parenchyma, the protocol enabled the diagnosis of acute pyelonephritis (APN) revealing the "regional parenchymal dysfunction," diagnostic of APN. Diffuse parenchymal diseases were characterized by increased residual cortical activity (RCA), and their progression was manifested as a deterioration of RCA. End-stage renal disease was characterized by lack of accumulation and retention. Trauma and leaks were identified with specific patterns. In renovascular hypertension (RVH), an increase in RCA after angiotension-converting enzyme inhibitors is diagnostic of RVH and prognostic of the beneficial effect of angioplasty on hypertension. In renal colic, stratification was possible into (1) complete or severe obstruction requiring immediate intervention, (2) mild obstruction allowing waiting, (3) spontaneous decompression (stunned kidney), and (4) no recent obstruction. In transplants, it enabled differentiation of acute tubular necrosis, acute or chronic rejection and nephrotoxicity, and identified infarcts, RVH, leaks and obstruction. Finally, this method allows for a quick semiquantification of renal function. The clinical usefulness of the MAG(3)-F(0) protocol in most congenital or acquired renal problems is proven through long-term clinical experience and has resulted in a substantial utilization of the test at our Center.

A comparison of unenhanced helical computerized tomography findings and renal obstruction determined by furosemide 99m technetium mercaptoacetyltriglycine diuretic scintirenography for patients with acute renal colic.

PURPOSE: We assessed unenhanced helical computerized tomography (CT) secondary findings as predictors of renal obstruction as determined by diuretic scintirenography, and determined their reproducibility. MATERIALS AND METHODS: We performed a retrospective review of the records of 77 consecutive patients with unenhanced helical CT findings (stones and secondary findings, including renal parenchymal edema, hydronephrosis, hydroureter, perinephric fat stranding, periureteral fat stranding and extravasation) of urinary lithiasis who had also undergone concomitant diuretic scintirenography during the initial emergency room evaluation during a 1-year period. Unenhanced helical CT films were independently reviewed by 2 attending radiologists (blinded to clinical outcome) to determine interobserver variability. The results were compared to those of diuretic scintirenography. RESULTS: Considerable interobserver variability, as evidenced by kappa values ranging from 0.26 to 0.60, existed for the diagnosis of secondary findings associated with urinary lithiasis on unenhanced helical CT. There was no significant difference in terms of CT findings between patients diagnosed by diuretic scintirenography as having high grade/complete obstruction and those with partial obstruction (p values 0.24 to 0.85 for the 6 unenhanced helical CT findings analyzed). Analyses of variance followed by Tukey's pairwise comparisons showed no significant difference in average number of unenhanced helical CT findings between patients with high grade/complete obstruction (mean plus or minus standard deviation 4.4 +/- 1.31), partial obstruction (4.4 +/- 1.30), and decompression/no obstruction (4.2 +/- 1.16). However, the mean number of unenhanced helical CT findings for patients with normal scintirenography/no obstruction (1.9 +/- 1.41) was significantly different from each of the other 3 diuretic scintirenography groups. Separate logistic regression analyses showed that each unenhanced helical CT finding, except for renal parenchymal edema and urinary extravasation, was a significant predictor of "any degree of obstruction" (high grade and partial obstruction groups) compared to "no obstruction" (decompressed and no obstruction groups). Odds ratios (95% confidence interval) ranged from 6.15 (2.25, 16.82) for perinephric fat stranding to 3.41 (1.30, 8.97) for hydroureter. When these analyses were repeated after exclusion of 8 patients with bladder/passed stones, only perinephric fat stranding and periureteral fat stranding remained significant predictors of "any degree of obstruction," with respective odds ratios of 4.21 (1.49, 11.91) and 4.08 (1.31, 12.65). CONCLUSIONS: Measures of agreement between trained, independent radiologists with respect to unenhanced helical CT secondary findings show considerable variability. The average number of CT consensus findings is not helpful in differentiating patients with variable degrees of obstruction, except for those with normal scintirenography/no obstruction. Unenhanced helical CT findings, except for renal parenchymal edema and urinary extravasation, are significant predictors of "any degree of obstruction" (high grade or partial obstruction) compared to "no obstruction" (decompressed or no obstruction). Therefore, unenhanced helical CT findings may be useful for identifying patients with any degree of obstruction but do not differentiate between those with high grade and partial obstruction.