The role of preoperative Tc-99m HMPAO-labeled leukocyte total-body scans in aortic prosthetic reconstruction.

PURPOSE: This study was performed to evaluate the utility of Tc-99m HMPAO-labeled leukocyte total-body scans (TBLS) for detecting remote septic foci before operation in patients undergoing aortofemoral vascular surgery. MATERIALS AND METHODS: Fifty-eight patients were screened before operation for inflammatory or infective disease, and a clinical score was assigned to each patient. Each patient had TBLSs. The relation between the clinical score and the TBLS result was determined. Patients with positive results of the TBLSs were examined, and the causes of these findings were treated before surgery. RESULTS: Ten of the 58 (17%) patients had a positive result of TBLSs. Of 31 patients with a clinical score of zero, 3 had positive findings of TBLS. No TBLS was positive in the 13 patients with a clinical score of 1. TBLS findings were positive in 7 of 14 of the combined patients with clinical scores of 2, 3, or 4. None of the patients showed signs of prosthetic vascular graft infection during the postoperative follow-up period. CONCLUSIONS: In conclusion, TBLSs can be used before aortofemoral vascular surgery, but only in patients with high clinical scores for inflammatory or infective disease to identify relevant infective foci that could cause vascular graft infection.

Sternal wound infection revisited.

Sternal wound infections (SWIs) can be subdivided into two types, superficial or deep, that require different treatments. The clinical diagnosis of superficial SWI is normally easy to perform, whereas the involvement of deep tissues is frequently difficult to detect. Therefore, there is a need for an imaging study that permits the assessment of SWIs and is able to distinguish between superficial and deep SWI. The present work was a prospective study aiming to evaluate the role of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labelled leucocyte scan in SWI management. Twenty-eight patients with suspected SWIs were included in the study. On the basis of clinical examination they were subdivided into three groups: patients with signs of superficial SWI (group 1), patients with signs of superficial SWI and suspected deep infection (group 2) and patients with suspected deep SWI without superficial involvement (group 3). Ten patients previously submitted to median sternotomy, but without suspected SWI, were also included in the study as a control group (group 4). All patients with suspected SWI had bacteriological examinations of wound secretion, if present. In addition 99mTc-HMPAO labelled leucocyte scan was performed in all patients. The patients of groups 1, 2 and 3 were treated on the basis of the clinical signs and microbiological findings, independently of the scintigraphic results. The patients of group 4 did not receive treatment. The final assessment of infection was based on histological and microbiological findings or on long-term clinical follow-up. Sensitivity, specificity, accuracy and positive and negative predictive values for scintigraphic and non-scintigraphic results were calculated. In the diagnosis of superficial and deep SWI, clinical and microbiological examination (combined) yielded, respectively, a sensitivity of 68.7% and 100%, a specificity of 77.3% and 80.8%, an accuracy of 73.7% and 86.8%, a positive predictive value of 68.7% and 70.6% and a negative predictive value of 77.3% and 100%. The scintigraphic results obtained in superficial SWI yielded a sensitivity of 56.2%, a specificity of 90.9%, an accuracy of 76.3%, a positive predictive value of 81.8% and a negative predictive value of 74.1%, while, by contrast, in deep SWI all of these values were 100%. Therefore, one can conclude that 99mTc-HMPAO labelled leucocyte scan permits accurate diagnosis of deep SWI, solving the main clinical problem in this field. In the present study the categorisation of patients without taking into account 99mTc-HMPAO labelled leucocyte planar scan findings caused a non-negligible number of cases of superficial SWI to be treated as though they were deep SWI. This "overestimation" led to unnecessary surgery, increased and prolonged use of antibiotics with more (higher) toxicity and additional expense.

Clinical usefulness of technetium-99m-HMPAO-labeled leukocyte scan in prosthetic vascular graft infection.

UNLABELLED: The infection of a prosthetic vascular graft (PVGI), although rare, is the most severe complication in reconstructive vascular surgery. The early diagnosis of this complication reduces the death rate from surgery. Aortofemoral graft infections differ clinically from peripheral graft infections in significant ways. The aim of this article is to evaluate separately the reliability of the 99mTc-HMPAO-labeled leukocyte scan or white blood cell count (WBC) in the early detection of both aortofemoral and peripheral graft infections. METHODS: One hundred sixty-two WBCs were performed on 129 consecutive patients with suspected aortofemoral (122 scans) and peripheral (40 scans) graft infection and in a 12-patient control group. Patients with suspected PVGI were categorized into three groups on the basis of their signs and symptoms on readmission: (a) patients with specific signs of graft infection (Group A); (b) patients with nonspecific signs of graft infection (Group B); and (c) patients with anastomotic aneurysms (Group C). Gram's stains of the perigraft exudate and graft cultures were performed and used as the gold standard in patients who underwent surgery. An 18-mo clinical follow-up was done to assess the presence or absence of graft infection in patients who did not have surgery. RESULTS: In patients with suspected aortofemoral graft infections, the overall sensitivity, specificity and accuracy of WBCs (Groups A, B, C) were 100%, 92.5% and 97.5%, respectively, whereas sensitivity, specificity and accuracy calculated in the patients with nonspecific signs of graft infection (Groups B, C) were 100%, 92.3% and 96.9%, respectively. In patients with suspected peripheral graft infections, sensitivity, specificity and accuracy were 100%. CONCLUSION: The white blood cell scan seems a reliable diagnostic method for early diagnosis of PVGI, and it is more useful in aortofemoral graft infections.

Efficient one-step direct labelling of recombinant antibodies with technetium-99m.

High-affinity bacterially expressed antibody fragments can nowadays be cloned from established hybridomas or, more conveniently, isolated directly from antibody libraries displayed on filamentous phage. Such antibodies can be tagged with C-terminal peptide tags containing one cysteine residue, which represents a convenient functionalisation site for a number of applications, including technetium-99m labelling. Here we describe a simple one-step method for 99mTc labelling of cysteine-tagged recombinant antibodies with more than 50% radionuclide incorporation. The labelled antibodies displayed full retention of immuoreactivity and good stability.

[The use of scintigraphy with labelled leukocytes: our experience]. / Uso della scintigrafia con leucociti marcati: nostra esperienza.

The authors describe various applications of scintigraphy with labeled leukocytes and its value in the diagnosis of gut diseases such as Crohn's disease, ulcerative colitis and related complications. Furthermore, the study of vascular prosthesis infection, cryptogenetic fever and abdominal sepsis, three cases of which are herein reported, is facilitated. The method, in conjunction with endoscopy and traditional radiology, revealed to be of great value in terms of sensitivity and specificity for the diagnosis of the aforementioned diseases. Therefore, the use of such method is encouraged in all those cases of abdominal sepsis of uncertain interpretation and in the evaluation of vascular prosthesis infection.

[New trends in the diagnosis of Crohn's disease]. / Nuovi orientamenti nella diagnostica del morbo di Crohn.

The Authors in reviewing the diagnostic techniques commonly used in Crohn's disease, focus their attention on Indium-111 scanning. The method seems useful, not only to point out the complications of the disease (stenosis, abscess, fistula) but especially for the follow up of patients after surgery with early diagnosis of a possible relapse.

Scintigraphic evaluation of disease activity in rheumatoid arthritis: a comparison of technetium-99m human non-specific immunoglobulins, leucocytes and albumin nanocolloids.

Technetium-99m-labelled, non-specific, polyclonal, human immunoglobulin G (99mTc-hIG) has been used to quantify synovial inflammation in rheumatoid arthritis. A comparison was carried out between the scintigraphic results obtained with this tracer, 99mTc-hexamethylpropylene amine oxime-labelled white blood cells (99mTc-WBC) and 99mTc-albumin nanocolloids (99mTc-NC). Twenty patients affected by rheumatoid arthritis and suffering from clinically active synovitis were studied with 99mTc-hIG. The number and sites of the involved joints had been previously assessed on the basis of the presence of pain and/or swelling. A radiological examination had already been carried out on all the joints. Two days after the 99mTc-hIG scan, 10 patients (group 1) underwent 99mTc-WBC scintigraphy and the other 10 (group 2) underwent a 99mTc-NC scan. The results show that the results of 99mTc-hIG and 99mTc-NC scans are in agreement with clinical examinations in the majority of cases. However, a certain number of positive joint scans corresponding to negative clinical examinations was found. The numerical distribution of these results according to the radiological stages seems to show that 99mTc-hIG is more useful than 99mTc-NC in the initial phases of the disease. The 99mTc-WBC scan was negative in a consistent percentage of the joints previously assessed as clinically and 99mTc-hIG scan positive.