Gadoxetic acid enhanced MRI for differentiation of FNH and HCA: a single centre experience

Objectives

Evaluation of enhancement characteristics of histopathologically confirmed focal nodular hyperplasias (FNHs) and hepatocellular adenomas (HCAs) with gadoxetic acid-enhanced MRI.

Methods

Sixty-eight patients with 115 histopathologically proven lesions (FNHs, n?=?44; HCAs, n?=?71) examined with gadoxetic acid-enhanced MRI were retrospectively enrolled (standard of reference: surgical resection, n?=?53 patients (lesions: FNHs, n?=?37; HCAs, n?=?53); biopsy, n?=?15 (lesions: FNHs, n?=?7; HCAs, n?=?18)). Two radiologists evaluated all MR images regarding morphological features as well as the vascular and hepatocyte-specific enhancement in consensus.

Results

For the hepatobiliary phase, relative enhancement of the lesions and lesion to liver enhancement were significantly lower for HCAs (mean, 48.7 (±48.4) % and 49.4 (±33.9) %) compared to FNHs (159.3 (±92.5) %; and 151.7 (±79) %; accuracy of 89 % and 90 %, respectively; P?<?0.001). Visual strong uptake of FNHs vs. hypointensity of HCAs in the hepatobiliary phase resulted in an accuracy of 92 %. This parameter was superior to all other morphological and dynamic vascular criteria alone and in combination (accuracy, 54–85 %).

Conclusions

For differentiation of FNHs and HCAs by means of MRI, gadoxetic acid uptake in the hepatobiliary phase was found to be superior to all other criteria alone and in combination.

Key Points

? EOB-MRI is well suited to differentiate FNHs and hepatocellular adenomas. ? For this purpose hepatobiliary phase is superior to unenhanced and dynamic imaging. ? Hepatobiliary phase (peripheral) hyper- or isointensity is typical for FNH. ? Hepatobiliary phase hypointensity is typical for hepatocellular adenomas. ? EOB-MRI helps to avoid misinterpretations of benign hepatocellular lesions.     

Das Verhalten der osmotischen Leukocytenresistenz während einer Knochenmarksfunktionsprüfung an Patienten mit chronischen Lebererkrankungen

Zusammenfassung Untersuchungen der Gesamtleukocytenzahl, des Differentialblutbildes und der osmotischen Leukocytenresistenz wurden bei Patienten mit Lebererkrankungen, mit und ohne portale Hypertension, während einer Knochenmarksfunktionsprüfung mit Pyrexal® vorgenommen. Die Befunde sprechen für einen erhöhten Leukocytenumsatz bei den Patienten mit portaler Hypertonie und gegen eine entscheidende Ausschwemmungshemmung der Zellen aus dem Knochenmark durch die Milz. Der mangelnde Leukocytenanstieg während des Testes scheint nur Folge der rascheren Abfilterung der Zellen in der gestauten Milz und Pfortader zu sein.

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Summary Numbers of leucocytes, differential blood count and osmotic resistance of leucocytes has been observed in patients with chronic liver diseases, with and without portal hypertension, during examination of bone marrow function with a lipopolysaccharide (Pyrexal®). The results give evidence for an augmented turnover of leucocytes and not for an inhibition of cell production in bone marrow by the spleen. The different total increase of leucocytes in patients with portal hypertension appears to be influenced by an increased white blood cell reservoir function of the congested spleen and portal vein.

     

Detection and quantification of<Emphasis Type="Italic"> Mycobacterium leprae</Emphasis> in tissue samples by real-time PCR

Real-time PCR technology has improved molecular diagnostics of many pathogens, but no such test is available for Mycobacterium leprae. In this report we describe the establishment and the pre-clinical evaluation of such an assay. The test achieved a theoretical analytical sensitivity limit of 194 M. leprae cells per skin biopsy specimen and facilitated quantification of mycobacteria in tissue over a range of 54–54,000,000 cells per sample. In punch skin biopsies from 39 untreated Ugandan patients with newly diagnosed leprosy, the clinical diagnosis could be confirmed in 88.9% of multibacillary and 33.3% of paucibacillary (microscopically negative) patients. Real-time detection thus did not increase the clinical sensitivity of PCR as compared to conventional protocols, in spite of its evidently high analytical sensitivity. On the other hand, as still no culture system exists for M. leprae, the assay appears to be a robust tool for detection of the bacterium in selected clinical situations, as well as for quantitation in experimental settings.     

Leprosy in a Pregnant Woman

Abstract Herein, we describe a case of leprosy in a 29-year-old pregnant southeast-asian woman who presented with joint pain and multiple disseminated erythematous macules, papules and plaques. Histological examination and stains for acid-fast bacilli from skin biopsies substantiated the clinical suspicion of a cutaneous mycobacterial disease and both should be performed in all patients with unidentified skin lesions. The definitive laboratory diagnosis of leprosy was achieved by the application of a species-specific real-time polymerase chain reaction from infected tissue.     

104. Postoperative Komplikationen nach Notfallresektion bei Colitis ulcerosa

Zusammenfassung Wegen toxischer Dilatation und massiver Blutung des Colons bei Colitis ulcerosa mußte bei 17 von 44 Patientenunter Notfallbedingungen operiert werden. 8 Patienten verstarben innerhalb von durchschnittlich 10 Tagen an den Folgen der kotigen Peritonitis nach Colonperforation. Zur Verhütung dieser schweren Komplikationen gilt die Anlage einer doppelläufigen Ileostomie sowie einer Transversum- und Sigmadekompressionskolostomie nach Turnbull mit zweizeitiger Proktokolektomie nach 6 Monaten als Methode der Wahl.     

Cost-Effective Modification of a Commercial PCR Assay for Detection of Methicillin-Resistant or -Susceptible Staphylococcus aureus in Positive Blood Cultures

Real-time detection of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) in cases of clinical bacteremia may promote appropriate antimicrobial therapy and infection control. Expense inherent to molecular diagnostics may prevent laboratories from utilizing real-time PCR for this purpose. BD GeneOhm StaphSR assay master mix was reconstituted and aliquoted into SmartCycler tubes in 25-μl volumes (freshly reconstituted master mix), with a portion being frozen at −70°C (frozen master mix). Incubation of 40 previously analyzed lysates from positive BacT/Alert SA and SN blood culture bottles (identified as 10 MRSA strains, 10 MSSA strains, 12 coagulase-negative Staphylococcus strains, and 8 Micrococcus strains) in freshly reconstituted master mix and master mix frozen between 1 week and 6 months generated the expected results in all PCRs. Similarly, positive- and negative-control reagents stored frozen at −70°C for up to 18 weeks yielded the expected reactions. Prospective analysis of 244 positive blood culture samples utilizing 1-week-frozen master mix and freshly reconstituted master mix yielded a 1.2% discordant rate upon initial testing due to three unresolved results (two unresolved results for freshly reconstituted master mix and one unresolved result for frozen master mix). Repeat testing produced a final 100% concordance rate between the two master mix preparations. Use of master mix that was frozen up to 6 months did not compromise performance of the BD GeneOhm StaphSR assay. This modification, resulting in less reagent waste, may allow a greater number of laboratories to consider real-time PCR methodology for detection of bacteremia caused by MRSA and MSSA.Detection and proper identification of pathogens from the bloodstream are arguably two of the most important aims of diagnostic assays performed in the clinical microbiology laboratory. Estimates of the number of patients with bloodstream infections per year in the United States are commonly cited at 200,000 patients (17), with mortality rates approaching 30% (24). Staphylococcus aureus alone is responsible for approximately 20% of the cases of bloodstream infection (6, 24), and up to 57% of S. aureus isolates recovered from blood cultures demonstrate resistance to methicillin (7, 24). Methicillin-resistant S. aureus (MRSA) bloodstream infection not only generates additional financial and service burdens for health care facilities to a greater extent than those caused by methicillin-susceptible S. aureus (MSSA) (3, 18, 21), but it also demonstrates a significantly higher mortality rate (4, 18). Taken together, these data suggest that rapid identification and methicillin resistance profiling of S. aureus bloodstream infection may be of benefit to patients and allied health care professionals.While nucleic acid hybridization assays (10) have been shown to directly identify S. aureus from positive blood cultures, only nucleic acid amplification modalities have taken the approach of delineating MRSA and MSSA from other Gram-positive coccus etiologies of bloodstream infection (16). In spite of these advances, some clinical microbiology laboratories may be apprehensive to implement these technologies due to financial considerations. Stamper et al. (20) reported on the utility of the BD GeneOhm StaphSR assay for direct identification and methicillin resistance profiling of coagulase-positive staphylococci from positive blood culture bottles, citing sensitivity and specificity values of ≥98.4% for MRSA and ≥96.7% for MSSA. In this report, we describe a modification of the protocol for reconstitution and storage of BD GeneOhm StaphSR assay master mix that not only allows for efficient detection of MRSA and MSSA but also promotes greater economy in reagent utilization.(The results of this work were presented in part at the 109th General Meeting of the American Society for Microbiology, Philadelphia, PA, 17 to 21 May 2009 [15].)In an institutional review board-approved protocol, one positive BacT/Alert SA or SN bottle (bioMérieux, Durham, NC) from consecutive septic episodes with a Gram stain morphology of Gram-positive cocci in pairs or clusters was processed to a lysate form for the BD GeneOhm StaphSR assay (BD Diagnostics, Ste-Foy, Quebec, Canada) per the manufacturer''s specifications. Vials containing lyophilized master mix were reconstituted with 225 μl of kit-provided diluent according to the manufacturer''s instructions; 25-μl aliquots were distributed into empty SmartCycler reaction tubes (Cepheid, Sunnyvale, CA) that were placed into a 4°C cooling block (freshly reconstituted master mix). In an experimental protocol, vials containing lyophilized master mix were reconstituted with 225 μl of kit-provided diluent; 25-μl aliquots were distributed into empty SmartCycler reaction tubes that were placed into a 4°C cooling block. The tubes were closed tightly, removed from the cooling block, and allowed to stand upright at −70°C for long-term storage protected from light (frozen master mix). Prior to storage, 3.0-μl aliquots of kit-provided nucleic acid (positive control) or sample buffer (negative control) were added to a subset of master mix aliquots.Aliquots (3.0 μl) of processed lysates were delivered to either frozen master mix tubes that were allowed to acclimate for 5 min in a 4°C cooling block or freshly reconstituted master mix. All reaction tubes were pulse centrifuged for 5 to 10 s and loaded onto a SmartCycler fluorescence thermal cycler (Cepheid) for 45 cycles of PCR. The lysates were subsequently frozen at −20°C. Potency studies involved incubation of archived positive (MRSA), reactive (MSSA), and negative lysates in both freshly reconstituted master mix and frozen master mix that had been stored for 1 week to 6 months at −70°C. In addition, control material frozen for 3, 9, and 18 weeks was subjected to PCR analysis. A prospective clinical study analyzed 244 lysates in tandem using freshly reconstituted master mix and 1-week-frozen master mix. All organisms from positive blood cultures were identified using standard microbiological techniques. Penicillinase-stable penicillin susceptibility results were determined by cefoxitin disk diffusion testing (22). Lysates demonstrating amplification inhibition (unresolved result) were thawed and repeat tested by PCR according to the manufacturer''s instructions. Concordant results generated by PCR from freshly reconstituted and frozen master mix constituted reference results.Forty previously analyzed lysates (10 MRSA strains, 10 MSSA strains, 12 coagulase-negative Staphylococcus [CNS] strains, and 8 Micrococcus strains) were incubated in freshly reconstituted master mix and in master mix frozen from 1 week to 6 months. The expected results were generated in all instances. Temporal cycle threshold (C_T) profiles for two representative lysates from each classification are illustrated in Fig. ​Fig.1.1. The C_T values for the two MRSA lysates (Fig. ​(Fig.1A)1A) ranged from 27.7 to 28.8 and from 26.1 to 27.0 and did not exhibit significant changes in frozen master mix potency (P = 0.58; one-way analysis of variance). Similarly, unchanged potency of frozen master mix over time was demonstrated with MSSA lysates (Fig. ​(Fig.1B),1B), with C_T value ranges of 27.1 to 28.2 and 24.1 to 25.6 (P = 0.11). Detection of internal-control nucleic acid (Fig. ​(Fig.1C)1C) was not significantly affected by interval of frozen master mix, with C_T value ranges of 32.9 to 34.3 and 33.5 to 34.6 (P = 0.73).Open in a separate windowFIG. 1.(A and B) Cycle threshold (C_T) values for BD GeneOhm StaphSR assay master mix frozen at variable intervals prior to incubation with lysates derived from clinical blood cultures yielding methicillin-resistant Staphylococcus aureus (A) and methicillin-susceptible Staphylococcus aureus (B). Data from two representative lysates are exhibited per panel and are shaded accordingly. (C) Internal-control C_T for frozen master mix incubated with representative coagulase-negative Staphylococcus lysates (solid black bars) and Micrococcus lysates (gray dotted bars).Preparation of assay controls with reconstituted master mix and subsequent storage at −70°C for 3, 9, and 18 weeks (mean of 12 determinations per parameter) resulted in expected amplification of target staphylococcal and internal-control sequences (Table ​(Table1).1). A mean C_T value increase was noted between 9- and 18-week-frozen prepared negative-control material (P = 0.003; t test for independent samples). In spite of this difference, the efficacy of 18-week-frozen master mix in amplification of internal-control nucleic acid (mean C_T value of 34.59; Table ​Table1)1) was largely unchanged from amplification of internal-control nucleic acid via freshly reconstituted master mix (mean C_T value of 34.63).

TABLE 1.

Mean cycle threshold (C_T) values for replicates of prepared BD GeneOhm StaphSR assay positive- and negative-control reagents frozen at −70°C for 3 weeks, 9 weeks, and 18 weeks^a

Travel-associated Coxiella burnetii infections: three cases of Q fever with different clinical manifestation

BACKGROUND: Certain activities expose travellers to Coxiella burnetii, the causative agent of acute human Q fever. Awareness of Q fever must be improved, also as a potential imported disease, but delayed seroconversion and serological cross-reactivity complicate the diagnosis. Granulomatous inflammation of liver and bone marrow can be typical histopathological findings. CASE PRESENTATIONS: We present three imported cases of Q fever with different clinical presentations, in which the travel history identified the sources of infection. CONCLUSIONS: Q fever should be suspected in any imported febrile disease of unknown origin. Clinical manifestations are variable and repeated serological testing is mandatory. In some cases diagnostic biopsies might help to establish early diagnosis.