Search

Acute focal bacterial nephritis (AFBN) is a localized bacterial infection of the kidney presenting as an inflammatory mass without frank abscess formation. We report a case of acute focal bacterial nephritis without pyuria in a five-month-old boy presenting with high urinary β2-microglobulin (β2-MG) and N-Acetyl-β-(D)-Glucosaminidase (NAG) levels. The infant initially presented with high-grade fever, and plain computed tomography (CT) showed a nearly isodense mass, and contrast-enhanced abdominal CT showed a wedge-shaped hypodense lesion. Enterococcus was detected in the subsequent urine culture. A diagnosis of AFBN was made on the basis of his high inflammatory reaction, contrast-enhanced abdominal CT findings and high urinary β2-MG and NAG levels. He was treated with Ceftriaxone and subsequent improvement in inflammatory reaction and contrast-enhanced CT findings were observed. Voiding cystourethrogram (VCUG) showed a grade V right VUR. This case suggests that urinary β2-MG and NAG levels may be useful additional markers for the diagnosis of AFBN without pyuria.

Objective: To evaluate different features between benign and malignant pulmonary focal ground-glass opacity (fGGO) on multidetector CT (MDCT)., Methods: 82 pathologically or clinically confirmed fGGOs were retrospectively analysed with regard to demographic data, lesion size and location, attenuation value and MDCT features including shape, margin, interface, internal characteristics and adjacent structure. Differences between benign and malignant fGGOs were analysed using a χ(2) test, Fisher's exact test or Mann-Whitney U-test. Morphological characteristics were analysed by binary logistic regression analysis to estimate the likelihood of malignancy., Results: There were 21 benign and 61 malignant lesions. No statistical differences were found between benign and malignant fGGOs in terms of demographic data, size, location and attenuation value. The frequency of lobulation (p=0.000), spiculation (p=0.008), spine-like process (p=0.004), well-defined but coarse interface (p=0.000), bronchus cut-off (p=0.003), other air-containing space (p=0.000), pleural indentation (p=0.000) and vascular convergence (p=0.006) was significantly higher in malignant fGGOs than that in benign fGGOs. Binary logistic regression analysis showed that lobulation, interface and pleural indentation were important indicators for malignant diagnosis of fGGO, with the corresponding odds ratios of 8.122, 3.139 and 9.076, respectively. In addition, a well-defined but coarse interface was the most important indicator of malignancy among all interface types. With all three important indicators considered, the diagnostic sensitivity, specificity and accuracy were 93.4%, 66.7% and 86.6%, respectively., Conclusion: An fGGO with lobulation, a well-defined but coarse interface and pleural indentation gives a greater than average likelihood of being malignant.

The importance of noninvasive imaging methods to bacterial infections is widely recognized. To obtain bacterial infection imaging with radioisotope-labeled nucleosides, bacterial thymidine kinase (tk) activities of Salmonella typhimurium with [(125)I]5-iodo-1-(2'-fluoro-2'-deoxy-β-d-arabinofuranosyl)uracil ([(125)I]FIAU) or 3'-deoxy-3'-[(18)F]fluorothymidine ([(18)F]FLT) were measured. The infection model in BALB/c mice was imaged with [(125)I]FIAU or [(18)F]FLT using small-animal Single Photon Emission Computed Tomography (SPECT) or Positron Emission Tomography (PET), respectively. The accumulated radioactivity of [(125)I]FIAU or [(18)F]FLT in the two strains showed a linearly increased pattern with increasing incubation time or bacterial numbers. The image clearly demonstrated a high uptake of [(125)I]FIAU and [(18)F]FLT in the bacterial infection site. [(18)F]FLT uptake in the infection site of was 7.286±2.405, whereas that in the uninfected site was 0.519±0.561. The relative activity ratio of the infected region in relation to the uninfected region was 2.98 at 4h after an injection with [(125)I]FIAU determined by biodistribution data. In conclusion, the bacterial tk activity was confirmed by the cellular uptake and imaging with [(125)I]FIAU or [(18)F]FLT. Therefore, a localized bacterial infection in living mice can be monitored using radioisotope-labeled nucleosides with a nuclear medicine imaging modality., (Copyright © 2012 Elsevier GmbH. All rights reserved.)

Focal bacterial nephritis is a symptom associated with inflammation of the kidneys. It may occur in children, usually indicating abnormal urinary tract development. In adults, urinary tract infection is generally caused by gram-negative bacteria, with Escherichia (E.) coli accounting for 80% of all infections. This case report describes a female patient in whom E. coli urinary infection caused, via ascending route, focal bacterial nephritis masquerading as renal cell carcinoma.

Background: Acute focal nephritis is an inflammatory process of the renal parenchyma affecting principally the cortex of the kidney. It is considered a midpoint in the spectrum of upper urinary tract infections, ranging from uncomplicated pyelonephritis to intrarenal abscesses. Until recently the hyperechoic sonographic appearance of this lesion was considered uncommon., Objectives: To determine the relative prevalence of hyperechoic and hypoechoic sonographic appearance of focal renal lesions in patients with the clinical diagnosis of acute pyelonephritis and to correlate the findings with those of the color Doppler examinations., Methods: We reviewed the sonograms of 367 patients hospitalized with the clinical diagnosis of acute pyelonephritis. The sonograms were reviewed for acute renal inflammatory changes. When a focal lesion was detected, we noted the echogenicity, side, form, location and color Doppler characteristics., Results: Abnormal sonographic findings related to the infection were found in 78 cases. In 52 patients a focal lesion was diagnosed. Forty-seven focal lesions appeared hyperechoic related to the adjacent parenchyma. These lesions were more frequently located at the upper pole and were wedge-shaped in most of the cases. The areas appeared hypo/avascular on the color Doppler examination., Conclusions: Our data suggest that the most common appearance of acute focal nephritis is an area of increased echogenicity in the parenchyma of the affected kidney.

Acute focal bacterial nephritis or acute lobar nephronia is an acute localized non-liquefactive bacterial kidney infection. Clinically, it may develop as an abscess and present as acute pyelonephritis but is distinguishable by the presence of a focal mass on imaging studies. The authors report the case of an 8-year-old girl with fever up to 39 degrees C and left flank pain of 6 days duration. On physical examination, she had nothing remarkable except tenderness and knocking pain over the left costovertebral angle. Post-contrast abdominal computed tomography revealed several wedge-shaped hypodense lesions in the left kidney. Urine culture grew Escherichia coli. Acute focal bacterial nephritis was diagnosed. The patient was treated with antibiotics and discharged on the 12th day of hospitalization.

To determine the value of helical computed tomography (CT) in the diagnosis, management and outcome of patients suspected of having descending necrotizing mediastinitis (DNM). Thirty-two patients with suspected DNM were submitted to contrast-enhanced single detector-row helical CT, four detector-row CT and 16 detector-row CT of the neck and chest. In 10/32 patients (group 1) no abnormality was observed in the neck or in the chest spaces on CT scan. These patients were all treated non-operatively. In 12/32 patients (group 2) CT showed the presence in the neck spaces of fluid collections, fasciitis, cellulitis, myositis, jugular vein thrombosis and lymphadenopathy; in all these patients the chest was unaffected. A cervical drainage was performed in ten patients. In the remaining ten patients (group 3), the neck infection involved the mediastinal spaces in all the cases and the pleural and pericardial spaces; CT findings included mediastinal cellulitis and fluid collections, pleural and pericardial effusions, venous thrombosis and lymphadenopathy. In these patients, a cervico-mediastinal drainage was performed and antibiotics were administered. The CT provides a highly accurate depiction of the presence and the spread of DNM. The CT findings and the extension of disease are important factors in order to predict for patient management and outcome.

Background: Correct identification of acute lobar nephronia (ALN) is necessary to prevent progression to renal abscess. The goal of this retrospective study was to determine whether the sonographic finding of severe nephromegaly (i.e. renal length greater than mean + 3 sd) is a preselection criterion for computed tomographic (CT) scanning in diagnosing pediatric ALN among children with an acute upper urinary tract infection., Design/methods: We evaluated a new imaging work-up scheme to detect pediatric ALN. All patients with urinary tract infection were evaluated with ultrasonography. If a markedly enlarged kidney or focal mass was present sonographically, CT scanning was done immediately. CT scanning was also performed when the patient had borderline nephromegaly and remained febrile for 72 h after start of antibiotic treatment. ALN diagnosis was made on the basis of positive CT findings., Results: Thirty patients with ALN (13 left, 7 right, 10 bilateral) and one with acute pyelonephritis were identified. ALN in all patients resolved after 3 weeks of antibiotic treatment. Thirty-nine of the 62 kidneys evaluated showed severe nephromegaly, and 10 had focal renal masses. With CT diagnosis of ALN as the reference standard, the sensitivity of severe nephromegaly was 90.0% and the specificity was 86.4%. When the focal renal mass was added as a combining predictor, the sensitivity further increased to 95%., Conclusions: Pediatric ALN was effectively predicted using sonographic findings of severe nephromegaly and/or focal mass before CT scanning.

Fever of unknown origin (FUO) and suspected focal infection or inflammation are challenging medical problems. The aim of this study was to assess the value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) in patients with FUO and patients with suspected focal infection or inflammation. All FDG PET scans ordered because of FUO or suspected focal infection or inflammation in the last 4 years were reviewed. These results were compared with the final diagnosis. Thirty-five FDG PET scans were performed in 35 patients with FUO. A final diagnosis was established in 19 patients (54%). Of the total number of scans, 37% were clinically helpful. The positive predictive value of FDG PET in these patients was 87% and the negative predictive value was 95%. Fifty-five FDG PET scans were performed in 48 patients with suspected focal infection or inflammation. A final diagnosis was established in 38 patients (82%). Of the total number of scans, 65% were clinically helpful. The positive predictive value of FDG PET in these 55 episodes of suspected infection or inflammation was 95% and the negative predictive value was 100%. It is concluded that FDG PET appears to be a valuable imaging technique in the evaluation of FUO and suspected focal infection or inflammation. Furthermore, FDG PET could become a useful tool for evaluating the effect of treatment of infectious and inflammatory processes that cannot reliably be visualised by conventional techniques. However, to assess the additional diagnostic value of this technique, prospective studies of FDG PET as part of a structured diagnostic protocol are warranted.

Focal bacterial nephritis or lobar nephronia represents an acute localized non-liquefactive infection of the kidney caused by bacterial infection. This is an uncommon form of pyelonephritis that can affect both adults and children. Imaging techniques, particularly CT scan, are necessary for diagnosis and to distinguish it from other conditions (abscess or renal masses) that require a different treatment. The authors describe a case of acute lobar nephronia in a 24-year-old man.

We report an 8-year-old boy with acute focal bacterial nephritis (AFBN). At the age of 3 months, he had a history of urinary tract infection and vesicoureteral reflux. He was admitted to our hospital because of high fever and costovertebral angle pain. Although acute pyelonephritis was suspected, neither pyuria nor cultures of blood and urine were positive. An initial ultrasonogram (US) of his kidneys was normal except for bilateral hydronephrosis. Two days later, however, a computed tomography (CT) revealed a poorly enhanced mass in the upper pole of the right kidney. Similar findings were also observed by US. Under the diagnosis of AFBN, he received antibiotics for 3 weeks. Voiding cystourethrogram showed both-sided vesicoureteral reflux and he underwent an operation. At present the mass of the kidney still remains, albeit its size tends to decrease. We suggest that an early examination of US or enhanced CT is necessary in cases with fever of unknown origin, considering the possibility of AFBN even if neither pyuria nor cultures of urine are positive.

Unlabelled: Polyethyleneglycol (PEG) liposomes have been shown to be excellent vehicles for scintigraphic imaging of infection and inflammation in various experimental models. In this article we report on a series of patients with possible infectious and inflammatory disease in whom the performance of 99mTc-PEG liposomes was evaluated. The results of 99mTc-PEG liposome scintigraphy were directly compared with those of 111In-immunoglobulin G (IgG) scintigraphy., Methods: Thirty-five patients (22 men, 13 women; mean age, 51 y; range, 20-76 y), suspected of having infectious or inflammatory disease, received 740 MBq 99mTc-PEG liposomes intravenously. Imaging was performed at 4 and 24 h after injection. Patients received 75 MBq 111In-IgG 24 h after administration of the liposomes. The scintigraphic results were compared and verified by culture, biopsy, surgery, and follow-up of at least 6 mo., Results: Of the 16 proven infections and inflammations, 15 were detected by 99mTc-PEG liposome scintigraphy: soft-tissue infection (n = 3), septic arthritis (n = 3), autoimmune polyarthritis (n = 2), infected hip prosthesis (n = 1), infected osteosynthesis (n = 1), spondylodiscitis (n = 1), infected aortic prosthesis (n = 1), colitis (n = 1), abdominal abscess (n = 1), and pneumonia (n = 1). 99mTc-PEG liposome and 111In-IgG scintigraphy both missed 1 case of endocarditis. In addition, an 111In-IgG scan of a patient with mild soft-tissue infection was false-negative. Concordantly false-positive scans were recorded from 2 patients, both with uninfected pseudarthrosis and focal signs of sterile inflammation. During liposomal administration, 1 patient experienced flushing and chest tightness, which rapidly disappeared after lowering the infusion rate. No other adverse events were observed., Conclusion: This clinical evaluation of 99mTc-PEG liposomes shows that focal infection and inflammation can be adequately imaged with this new agent. The performance of 99mTc-PEG liposomes is at least as effective as that of 111In-IgG. With the simple and safe preparation and the physical and logistic advantages of a 99mTc label, 99mTc-PEG liposomes could be an attractive agent for infection or inflammation imaging.

Computed tomography (CT) and magnetic resonance (MR) imaging were performed in three diabetic patients with endophthalmitis and liver abscess secondary to Klebsiella pneumoniae infection. Ocular abnormalities included early uveoscleral thickening, fulminant exudative vitreous humor, and late phthisis bulbi. Characteristic imaging findings of endophthalmitis in diabetic patients with liver abscess should raise a high index of suspicion for K pneumoniae infection.

The radionuclide investigation was performed 1-3 and 24 hours after injection of a radiopharm preparation and included the single photon emission computed tomography of the heart and scintigraphy of the whole body. Inflammation foci were found on the scans as hyperfixation foci of autoleukocytes labeled with 99mTc-HMPAO (hexamethylpropilene aminooxime). Four patients had abscesses with 0.8-1.5 cm diameter in projection of the aortal and mitral valves of the heart, and in 10 patients there were foci of inflammation and suppuration of extracardiac localization (in the area of the operation wound, anterior mediastinum, frontal sinuses, transverse colon, parietal pleura). The data obtained convincingly speak of high sensitivity and specificity of radionuclide diagnostic methods with the help of labeled elements of the whole blood in recognizing latent inflammatory and suppurative processes in cardiosurgical patients at the pre- and postoperative periods.

Unlabelled: Indium-111-labeled plasma proteins, such as albumin, transferrin and IgG, have been proven useful to image infection. We reported previously that 111In-labeled human monoclonal antibody, IgM 16.88 (In-IgM) also would localize at the site of infection. However, the kinetics of blood clearance, distribution and infection uptake have not been investigated. We compared the kinetics of distribution and infection uptake of In-IgM 16.88 with that of in-polyclonal IgG in rats with focal infection., Methods: Both IgM 16.88 and polyclonal IgG were labeled with 111In using a bifunctional chelating agent, LiLo. The labeling efficiency was > 95%. Focal infection was induced in rats by an intramuscular injection of E. Coli in the right thigh. In-IgM (30-40 microCi) was injected into five groups of rats (five rats/group). The rats were killed at 4, 8, 16, 24 and 36 hr. The percent injected dose (%ID) in blood, infection muscle, control muscle, liver, spleen and kidney were determined. Similar studies were performed with In-IgG., Results: The In-IgM activity in blood at 4 hr postinjection was 27% which decreased to 2% by 36 hr. In contrast, the In-IgG blood activity was 40% at 4 hr and 20% at 36 hr. The infection/ muscle (I/M) ratios are higher with In-IgM at all time points postinjection compared to that of In-IgG. At 24 hr, the I/M ratio was 22 compared to 9 with In-IgG. At the same time point, the infection/ blood (I/B) ratio with In-IgM was 2.7 compared to only 0.8 with that of In-IgG. In-IgM was taken up mostly by the liver compared to diffuse abdominal uptake of IgG., Conclusion: These result indicate that In-IgM produces higher lesion to background ratio when compared to In-IgG and, therefore, is potentially useful to image infection in patients.

Unlabelled: In previous studies we have shown that liposomes sterically stabilized with polyethylene glycol (PEG), preferentially localize in infectious and inflammatory foci. In this study, we further optimized the formulation of PEG liposomes for infection imaging in a rat model., Methods: The biodistribution and imaging characteristics of different liposomal formulations labeled with 99mTc were determined in rats with S. aureus infection of the left calf muscle. The influence of liposomal size (mean diameter varying from 90 nm to 220 nm) as well as circulation time (modulated by inclusion of 0-10 mole% phosphatidylserine) were studied., Results: The smallest liposomes displayed improved characteristics for infection imaging: 90-nm liposomes revealed the highest abscess uptake (1.6% +/- 0.4% ID/g, 24 hr postinjection) in combination with the lowest splenic accumulation (6.9% +/- 0.7% ID/g, 24 hr postinjection) as compared to the larger sized preparations. Enhanced abscess-to-blood ratios (4.0 versus 1.3 at 24 hr postinjection) were obtained by including 1.0 mole% phosphatidylserine in the lipid bilayer of the PEG liposomes. However, enhanced blood clearance of these liposomes reduced their absolute abscess uptake., Conclusion: These results indicate that the in vivo behavior of PEG liposomes can be modulated to optimize their characteristics for infection imaging.

Although cytomegalovirus (CMV) is commonly found in the lungs of patients with acquired immunodeficiency syndrome (AIDS), CMV is an infrequent cause of pneumonia in AIDS. We describe an unusual case of proven CMV pneumonia in an AIDS patient that manifested as a large mass on chest radiography and computed tomography. The mass regressed on antiviral therapy. CMV pneumonia should be included in the differential diagnosis of a lung mass in patients with AIDS.

Objective: To evaluate the clinical use of radionuclide-labeled white blood cell scintigraphy in the detection of focal sepsis., Design: Prospective clinical study., Setting: A medical/surgical 12-bed intensive care unit (ICU) in a university hospital., Patients: 26 trauma and surgical patients affected by sepsis of unknown origin were studied., Measurements and Results: After the usual diagnostic approach, patients were submitted to a total body scan by using the patient's leukocytes labeled with technetium-99m (99m-Tc) HMPAO; three scintigraphy were performed within 20 h of tracer injection; the result of scan was completed with all clinical and instrumental data, including ultrasound (US) arnd computed tomography (CT), and the diagnostic efficacy was demonstrated for each patient on discharge from the ICU. The scan was able to detect 20 sites of infection; it was possible to rule out 11 suspected sites; only in two cases was the result considered to be false positive or false negative; in two cases the result was considered to be uncertain. These results show the high sensitivity (95%), specificity (91%) and accuracy (94%) of the method., Conclusions: In ICU patients with sepsis, nuclear medicine can provide additional data, as the injection of radionuclide-labeled white blood cells (WBCs) allows the imaging of sites of infection. Analysis of our results suggests that scintigraphy with 99m-Tc-labeled WBCs can be considered a useful tool in the detection of the source of infection.

An increasing number of patients are presenting with central nervous system complications of human immunodeficiency virus infection. New imaging technologies such as magnetic resonance imaging, magnetic resonance proton spectroscopy, single-photon emission computed tomography, and positron emission tomography are playing an ever-increasing role in the diagnosis of these complications. As therapeutic modes improve, imaging may assume a growing role in monitoring the responses to therapy among these patients.

Unlabelled: We have developed a leukocyte-avid, 99mTc-labeled peptide (P483H) as a potential imaging agent for infection. P483H contains the heparin-binding region of platelet factor-4 (PF-4) and a lysine-rich sequence for rapid renal clearance. Technetium-99m-P483H was evaluated for its ability to selectively label white blood cells (WBCs) in vitro and to detect focal E. coli infections in rabbits., Methods: Technetium-99m-P483H was incubated with citrated whole human blood, layered onto WBC isolation media and subjected to density gradient centrifugation to measure WBC-associated radioactivity. Indium-111-WBCs and 99mTc-gluceptate were used as controls. In the in vivo model, E. coli infected rabbits were imaged and necropsied 4 hr after administration of 99mTc-P483H. Infected and contralateral control muscles were evaluated for %ID, %ID/g, Imax (muscle sample showing the highest uptake, i.e., %ID/g) and Imax-to-blood and Imax-to-control muscle ratios. Indium-111-WBCs, 111In-DTPA, 131I-albumin (HSA), 99mTc-nanocolloid, 67Ga and 99mTc-gluceptate were evaluated as in vivo controls., Results: Technetium-99m-P483H associated predominantly with WBCs in vitro, and 99m-Tc-P483H provided high contrast images of infection in vivo. In vitro, 73% of 99mTc-P483H radioactivity was associated with WBCs. Technetium-99m-P483H outperformed 111In-WBCs, 111In-DTPA, 131I-albumin, 99mTc-nanocolloid, 67Ga-citrate and 99mTc-gluceptate with an infection Imax average of 0.062 %ID/g (+/- 0.029; n = 48). Technetium-99m-P483H also outperformed all controls, including 111In-WBCs, 111In-DTPA, 131I-albumin, 99mTc-nanocolloid, 67Ga-citrate and 99mTc-gluceptate. The Imax-to-blood and Imax-to-control muscle ratios for 99mTc-P483H averaged 3.1 (+/- 2.4) and 26.8 (+/- 16.8), respectively, and again outperformed all controls., Conclusion: Technetium-99m-P483H associates predominantly with WBCs in vitro and identified focal infections in vivo within 4 hr versus conventional imaging agents. Additionally, the agent showed rapid blood clearance and exclusive renal excretion, which provides a clear abdominal field for imaging abdominal infections.

Unlabelled: To determine the potential of sterically stabilized liposomes to image infectious and inflammatory foci, the in vivo behavior of 111In-labeled PEGylated (coated with polyethylene glycol) liposomes was studied in a rat model., Methods: Indium-111-PEGylated lipsomes were administered intravenously to rats infected with S. aureus in the left calf muscle. The distribution of the radiolabel was studied by gamma counting of dissected tissues and gamma camera imaging for 48 hr. As a reference agent, the preparation of 111In-IgG was included in these studies., Results: Clearance of the PEGylated liposomes from the blood compartment was similar to the clearance of 111In-IgG in this model (t1/2 approximately 20 hr). Uptake of the radiolabel in the abscess with the 111In-liposomes was twice as high as the uptake following injection of 111In-IgG (2.7%ID/g versus 1.1%ID/g at 48 hr postinjection). Tissue counting revealed that abscess-to-muscle ratios reached values up to 20 and 34 (24 and 48 p.i., respectively). As early as 1 hr postinjection, the abscess could be visualized scintigraphically., Conclusion: The in vivo characteristics of this liposomal formulation in this rat model indicate that sterically stabilized liposomes labeled with gamma emitters might be a valuable addition to the arsenal of radiopharmaceuticals currently used for infection imaging.

Patients who are human immunodeficiency virus (HIV) antibody positive are at increased risk of life threatening infection. Scintigraphic imaging with Ga-67 citrate has been used to identify the presence and site of focal infection. However, focal accumulation of Ga-67 is not specific for infection. A retrospective study was performed to compare the accuracy of Ga-67 citrate and pooled human polyclonal immunoglobulin G (HIG) labeled with Tc-99m HIG and In-111 HIG in identifying infection in HIV antibody positive patients. Twenty-five studies were performed using Ga-67 and Tc-99m HIG were compared with a second group of 25 studies using In-111 HIG in HIV antibody positive patients presenting with fever, but without localizing symptoms or signs. In-111 HIG identified 20 of 22 sites of infection and also accumulated in 5 sites without infection (accuracy = 90%). This was significantly more accurate (X2, P < 0.05) than Ga-67 which identified 19 of 20 sites of infection, but accumulated in 18 sites without infection (accuracy = 74%) and Tc-99m HIG which identified infection in 11 of 20 sites, but accumulated in 8 sites without infection (accuracy = 77%). There was no significant difference between the accuracy of Ga-67 and Tc-99m HIG. From this preliminary study In-111 HIG would seem to be the best agent for identifying infection in HIV antibody positive patients with fever.

Objective: Infection imaging with a 99mTc-labeled chemotactic peptide was evaluated in a rabbit model of Escherichia coli infections in burned tissue., Materials and Methods: The peptide was radiolabeled with 99mTc via the hydrazino nicotinamide derivative. Three groups of six animals were studied: (group A) unilateral infected burns; (group B) bilateral burns with unilateral infection; and (group C) uninfected burns. Twenty-four hours after injury, groups A and B were infected, and 8 hours later, all animals were injected with approximately 0.50 mCi of 99mTc-peptide., Measurements and Main Results: In groups A and B, excellent images of the infections were obtained at 3 to 4 and 16 to 18 hours after injection of the peptide. At 3 to 4 hours after injection, the target-to-background ratios (T/B) were 3.12 +/- 0.28 for group A and 4.33 +/- 0.61 for group B (p = n.s.). At 16 to 18 hours, the T/B ratios increased significantly (p < 0.01): group A = 8.10 +/- 1.03 and B = 7.70 +/- 1.25. The T/B ratio for group C was only slightly greater than unity., Conclusions: These results indicate that 99mTc-labeled chemotactic peptides are effective radiopharmaceuticals for the rapid detection of focal sites of infection within thermally injured tissues.

The aim of the present study was to evaluate whether the different methodologies used for human polyclonal immunoglobulin (HIG) preparation can affect the radiochemical purity of 99mTc-HIG and its binding affinity to infection sites. Three intravenous immunoglobulin preparations, beta-propiolactone treated, hydrochloric acid/pepsin treated, and an unmodified HIG molecule were studied. The HIG preparations were analysed by size-esclusion HPLC. The UV chromatogram profiles obtained showed some percentage of polymeric and dimeric fractions in all of them. The three HIG studied were directly radiolabelled via 2-mercaptoethanol reduction. Lyophilized kits containing 1 mg of HIG and a small amount of MDP(Sn) solution were prepared and then radiolabelled by adding pertechnetate-99m. The radiolabelled products, evaluated by ITLC, showed high radiochemical purity and in vitro stability. Biodistribution studies were performed in mice with an infection in the right thigh induced by the im administration of a single isolate of S. aureus, in order to compare the ability of 99mTc-HIG to detect an infectious focus. This study suggests that any damage during immunoglobulin treatment can influence the in vivo behaviour of 99mTc-HIG.

The serendipitous discovery that radiolabeled nonspecific immunoglobulin G (IgG) accumulates at a site of focal inflammation has led to the development of a new radiopharmaceutical for inflammation scanning, 111In-IgG. This reagent has been extensively studied in humans with focal infection and has been shown to be both safe and effective. It has been especially useful in the evaluation of patients with possible abdominal and skeletal infection, with the ability to perform serial scans being an important attribute in terms of determining "proof of cure." Preliminary data suggest that this approach may be particularly useful in immuno-compromised patients and may find a role in the quantitative assessment of patients with such noninfectious inflammatory processes as rheumatoid arthritis and inflammatory bowel disease. A new method of labeling IgG with technetium, via the hydrazino nicotinamide derivative, holds promise in terms of substituting this more practical radionuclide for indium. However, caution must be directed against total substitution, because such processes as suspected vascular or skeletal prosthesis infection may require the longer half-life of 111In for satisfactory diagnosis. When one compares the results obtained with radiolabeled IgG against the ideal specifications for a radiopharmaceutical to be used for inflammation imaging, most of the requirements are met. The major weakness of this approach is that even with the technetium-labeled reagent, a minimum of 6 to 12 hours is necessary for a scan to become positive, which is not acceptable in the evaluation of acutely evolving processes. Development of other radiopharmaceuticals for this purpose remains to be accomplished.

We have recently developed a procedure to label liposomes containing reduced glutathione (GSH) with 99mTc using the lipophilic chelator, hexamethylpropyleneamine oxime (HMPAO). In the present study, we evaluated the use of 99mTc-liposomes to detect focal infection sites in rats. Rats were infected in the thigh by intramuscular injection with Staphylococcus aureus followed 24 hr later by an intravenous injection of 99mTc-liposomes, 67Ga-citrate, or 99mTc-human serum albumin (HSA). The animals were imaged under a gamma camera and subsequently killed at 4, 24 or 48 hr for tissue biodistribution studies. In contrast to infected rats receiving 67Ga-citrate or 99mTc-HSA, abscesses were prominently localized within 2 hr in rats after 99mTc-liposome injection, and continued to increase in activity up to 24 hr. Abscess-to-muscle ratios calculated from 24-hr biodistribution data obtained from tissue sampling were 35.3 +/- 7.6 for 99mTc-liposomes, 4.1 +/- 0.7 for 67Ga-citrate and 8.0 +/- 1.0 for 99mTc-HSA. These studies show the potential of using 99mTc-liposomes to localize infection.

Acute lobar nephronia (ALN), a term analogous to acute lobar pneumonia, refers to a renal mass caused by acute focal infection without liquefaction. An alternative term is acute focal bacterial nephritis (AFBN). Fever, flank pain or back pain are the most frequently encountered clinical characteristics. Imaging modalities used to establish a definite diagnosis of acute lobar nephronia included sonography, computed tomography and nuclear medicine. Uroradiographic findings in this condition can mimic a renal abscess or neoplasm. Further distinction between acute lobar nephronia and other renal masses is aided by the appropriate use of renal sonography and computerized tomography is the most effective and least costly method in diagnosis. Serial sonograms can be used to monitor response to antibiotic therapy. Clinical and uroradiographic characteristics of a six year-old female patient with acute lobar nephronia are presented, along with a review of literature.

We synthesized and evaluated four hydrazino nicotinamide (HYNIC) derivatized chemotactic peptide analogs: For-NleLFK-HYNIC (HP1), For-MLFK-HYNIC (HP2), For-MLFNH(CH2)6NH-HYNIC (HP3), and For-MLF-(D)-K-HYNIC (HP4), for in vitro bioactivity and receptor binding. The peptides were radiolabeled with 99mTc via a glucoheptonate co-ligand and their biodistribution determined in rats (n = 6/time point) at 5, 30, 60 and 120 min after injection. Localization of the peptides at sites of deep thigh Escherichia coli infection was determined by radioactivity measurements on excised tissues in rats (n = 6/time point) and rabbits as well as scintillation camera imaging in rabbits (n = 6). All peptides maintained biological activity (EC50s for O2 production by human PMNs: 12-500 nM) and the ability to bind to the oligopeptide chemoattractant receptor on human PMNs (EC50s for binding: 0.12-40 nM). After incubation with 99mTc-glucoheptonate, radiolabeled peptides were isolated by HPLC at specific activities of > 10,000 mCi/microM. Technetium-99m-labeled peptides retained receptor binding with EC50s < 10 nM. Blood clearance of all four peptides was rapid. Biodistributions of the individual peptides were similar, with low levels of accumulation in most normal tissues. In rats, all of the peptides concentrated at the infection sites (T/B ratio: 2.5-3:1) within 1 hr of injection. In rabbits, outstanding images of the infection sites were obtained, with T/B ratios of > 20:1 at 15 hr after injection. This study demonstrates that 99mTc-labeled chemotactic peptide analogs are effective agents for the external imaging of focal sites of infection.

Pooled human immunoglobulin labeled with indium-111 (111In-HIgG) was used to identify the presence and extent of infection in patients positive for human immunodeficiency virus (HIV), presenting with either symptoms and/or signs of acute chest infection or with pyrexia without localizing signs or symptoms. Fifty-five studies were performed in 51 patients with suspected chest infection or pyrexia without localizing signs. Of these, 111In-HIgG identified intrapulmonary accumulation in 17 patients with Pneumocystis carinii pneumonia, eight with bacterial pneumonia, five with cytomegalovirus pneumonia, three with pulmonary Mycobacterium avium intracellulare infection and one with a fungal pneumonia. There was no intrapulmonary accumulation of 111In-HIgG in five patients with bronchopulmonary Kaposi's sarcoma and in three patients with intrathoracic lymphoma. Quantification of lung/heart activity was significantly increased (p < 0.05) in patients with active chest infection compared with those with intrapulmonary tumor or no active lung pathology. Indium-111-HIgG scintigraphy also localized at 14 sites of extrapulmonary infection, including six patients with colitis. There were no false-negative studies but false-positive uptake was seen in four studies. These results confirm that 111In-HIgG correctly identifies the presence and extent of infection in patients positive for HIV antibody.

To evaluate the usefulness of 99mTc-HMPAO-labeled leukocytes and 99mTc-labeled polyclonal human immunoglobulin G (Technescan HIG) in the diagnosis of focal purulent disease, 31 comparative scintigraphies were done in 30 patients with known or strongly suspected focal infection. Focal purulent disease was the final diagnosis in 19 patients. Technetium-99m-labeled leukocytes showed 16 true-positive, no false-positive, 11 true-negative and 3 false-negative findings. The corresponding figures for 99mTc-labeled HIG were 11, 2, 9 and 8. The sensitivity and specificity of imaging with labeled leukocytes were 84% and 100%, respectively, and with labeled HIG, 58% and 82%, respectively. The overall accuracy of the leukocyte scan was significantly better than that of the HIG scan (90% versus 67%, p < 0.001). Thus, if focal infection is suspected, scintigraphy with 99mTc-labeled leukocytes is the preferable method. No cases exhibited a better imaging result with 99mTc-HIG scintigraphy than with 99mTc-labeled leukocytes.

To evaluate the applicability of Tc-99m HMPAO leukocyte scintigraphy in the assessment of focal infections in children, we retrospectively analyzed 26 studies performed between 1988 and 1992. All patients (n = 25, age range 1 month-15 years) were severely ill and suspected to have invasive bacterial infection. In each case, whole body scintigraphy was performed 2-4 hours after injection of autologous labeled leukocytes. There were 8 true positive and 14 true negative cases; specificity was 88% and sensitivity 80%. The two false negative findings were observed in patients on immunosuppressive therapy; both had fungal infections. In one case, atypical non-specific bowel accumulation of the tracer was falsely interpreted as an abscess. The other false positive finding was hip accumulation in a patient who later turned out to have Mucha-Haberman disease; transient synovitis may explain the finding. Of the eight true positive cases, six had an invasive infection focus and two had an aseptic inflammatory process. Tc-99m HMPAO leukocyte scintigraphy is a valuable method in the assessment of focal inflammation in children, including infants.

Indium-111 oxine labelled leucocyte (111In oxine leucocyte) scintigraphy is the test of choice in detecting occult infection and localising focal inflammation. 111In oxine labelling is technically difficult and expensive and leucocyte labelling with technetium-99m stannous colloid (99mTc Sn colloid) has been considered to be an alternative. Leucocytes from 40 cases referred for investigation of occult infection or localisation of inflammation were simultaneously labelled with 111In oxine and 99mTc Sn colloid with dual isotope acquisition performed at 1, 3 and 24 h. Twenty-four hour 99mTc Sn colloid scans were corrected for 111In downscatter. Each case was independently interpreted by two experienced observers. Twenty-one patients demonstrated positive 111In oxine leucocyte scans. Using 111In oxine leucocyte scans as the gold standard, 99mTc Sn colloid leucocyte scanning had an overall sensitivity of 86% and a specificity of 95%. Clinical follow-up verified that three patients had false negative 99mTc Sn colloid leucocyte scans and one patient had a false positive. Further clinical evaluation of 99mTc Sn colloid labelled leucocytes is required before they can become a reliable replacement for 111In oxine leucocytes.

Acute lobar nephronia (acute focal bacterial nephritis) has recently been recognized as an infectious process of the kidney. It is a radiologic diagnosis characterized as a nonliquifiable inflammatory renal mass associated with signs and symptoms of bacterial pyelonephritis. We present the successful management of a renal allograft recipient who had radiologic evidence of acute lobar nephronia within the graft six weeks after placement of an internalized ureteral stent.

Fever, a frequent manifestation in acute leukaemia patients who develop treatment-induced neutropenia, usually resolves when the neutrophil count returns to normal irrespective of whether an infective agent is isolated or not. A persistent pyrexia following neutrophil recovery and associated with multiple negative microbiological cultures should signal a careful search for a deep-seated fungal infection in any leukaemic patient who is complete remission. We report here a 39-year-old Chinese man with acute myeloid leukaemia in first complete remission whose unresolved fever after recovery from consolidation therapy-induced neutropenia was ultimately confirmed to be caused by focal hepatic candidal microabscesses by an open liver biopsy.

Severe focal viral encephalitis is most commonly caused by herpes simplex virus (HSV), but other viruses may act as etiologic agents as well. Acyclovir (ACV) is the standard therapy for HSV encephalitis, but the mortality of 28% and defect healing rate of about 35% are still unsatisfactory. Furthermore, ACV has virtually no effect on other pathogens of viral encephalitis, except for varicella-zoster virus (VZV). It is well known that beta-interferon (beta-IFN) has a broad antiviral spectrum, and it has been demonstrated in vitro that beta-IFN in combination with acyclovir has synergistic inhibitory effects on HSV. To investigate if the combination of ACV with and without beta-IFN might also be of significance for the treatment of severe viral encephalitis, we performed a retrospective study. A case record form was sent to all 278 West German children's hospitals. The response rate was 78%. A total of 301 patients were reported, of whom 214 received specific antiviral therapy with either ACV alone (n = 179) or ACV plus beta-IFN (n = 35). No overall differences between ACV monotherapy and the combination therapy were observed. However, in a subgroup of 41 patients (ACV n = 30, ACV plus beta-IFN n = 11) who had low-density areas of the temporal lobes on cranial computed tomography scans, compatible with severe focal encephalitis, sequelae due to defect formation and mortality were significantly (p = 0.014) reduced in patients who had received combination therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Nonspecific polyclonal immunoglobulin (IgG), prepared from pooled human serum gamma globulin and labeled with 111In has been reported to be equivalent to antigen-specific antibody in the detection of focal infection or inflammation during the first 24 hr after injection. We describe our experience in a Phase II clinical study using 111In-IgG in 15 patients (8 males, 7 females) ranging from 26 to 80 (mean = 50) yr of age with suspected focal infection/inflammation. Pathologic confirmation was obtained in 5/15 cases. A combination of clinical course, laboratory results, and other imaging procedures were used to categorize the other 10 patients. One possible false-negative involved a presumed aspiration pneumonia in a patient with a history of aspiration, bibasilar infiltrates on chest film, and no other identified source of infection. Otherwise, there were 10 confirmed positives, 4 confirmed negatives, and no false-positives. Our findings confirm earlier reports that 111In-IgG may be a superior imaging agent for infection/inflammation with practical advantages over 67Ga-citrate and 111In-labeled leukocytes.

A variety of radioactive agents, injected directly intravenously have demonstrated foci of inflammation by gamma camera imaging, avoiding the in vitro preparation of labeled leukocytes. This study sought to find out if any of these agents mimicked the biodistribution in abscesses and non-target organs of labeled mixed leukocyte suspensions. Eight different agents were compared with 111In-oxine labeled leukocytes in an acute soft tissue E. coli abscess and an acute arthritic lesion in 24 dogs one day after intravenous administration. These included 67Ga-citrate, human and canine polyclonal immunoglobulin (IgG), rabbit anti-dog polyclonal IgG, serum albumin, monoclonal antibody TNT-1 F(ab')2 against nuclear antigens, 57Co-porphyrin and serum albumin nanocolloid. None of these agents achieved abscess concentrations approaching those obtained with labeled leukocytes, and their abscess/blood and abscess/muscle concentration ratios were considerably lower. No statistically significant differences were found between the different radiolabeled proteins evaluated. The abscess concentration of 99mTc-nanocolloid was much lower than that of other agents, and the results with the oldest agent, 67Ga-citrate, were disappointing in these acute experiments.

In 35 patients suspected of an infectious focus, the outcome of scintigraphy with 111In-labeled autologous leukocytes (WBC) and 111In-labeled human nonspecific immunoglobulin G (IgG) was evaluated in a prospective comparative study. Clinical, roentgenologic and microbiologic findings were considered to be proof of the presence of infection or inflammation. In this group of patients with mainly subacute infections, 111In-IgG scintigraphy performed significantly better than 111In-WBC scintigraphy, especially in infections of the locomotor system, but also in various soft-tissue infections. Both techniques showed disappointing results in patients with disseminated yersinia infection and in some patients with tuberculosis. Overall sensitivity and specificity was 74% and 100% for 111In-IgG scintigraphy and 52% and 78% for 111In-WBC scintigraphy, respectively.

The abilities of 99Tcm-labelled monoclonal anti-human granulocyte antibody (AGAb) and 111In-labelled nonspecific polyclonal human immunoglobulin (IgG) to localize at focal sites of inflammation were compared in rats with deep thigh infection due to E. coli. The radiolabelled antibodies were coadministered followed 4-6 and 24 h later by imaging and biodistribution studies. At 4-6 h after injection, the target to background ratio (T/B, lesion to contralateral leg) and percentage residual activity (% RA, counts in the lesion/total body counts) were nearly identical for both antibody preparations. At 24 h, T/B and % RA increased significantly (P less than 0.001) for both proteins but differences between the agents were not significant. In vitro analysis of the binding of AGAb and human polyclonal IgG to rat granulocytes showed a low level of binding with both agents. These results suggest that the primary mechanism of localization, by either antibody preparation in this model, is not antigen related. 111In-labelled nonspecific human IgG and 99Tcm-AGAb are equivalent reagents for the detection of focal sites of infection in the rat.

Eleven patients with suspected foci of inflammation and/or infection were scanned with 111In-labeled polyclonal human IgG. Seven patients were suspected of having the source of their infection in the abdomen, three in the musculoskeletal system and one in the thoracic aorta. The test was truly positive in seven patients, truly negative in three and falsely negative in one. All the true positive cases showed abnormally increased radiopharmaceutical uptake at the site of infection by six hours, suggesting the diagnosis, although the intensity of uptake increased progressively 24 hours later. There were no untoward effects noted in this series. This examination is potentially useful in the early depiction of focal sources of infection/inflammation.