Effect of absorbable topical hemostatic agents on the relaxation time of blood: an in vitro study with implications for postoperative magnetic resonance imaging

Does the use of Surgicel affect postsurgical radiological follow-up of kidney tumors?

Remaining Surgicel in the body can be mistaken for complications such as hematoma, abscess, or tumor recurrence in paraclinical examinations after surgery. We have presented the case of kidney cancer who underwent radical nephrectomy. In radiological follow-ups, hematoma was reported in the surgery site. The typical appearance of Surgicel on a postoperative CT scan is characterized by air trapped bubbles. Surgicel exhibits a short relaxation time on T2-weighted images. It is important to differentiate the remaining Surgicel from cases such as hematoma, abscess and tumor recurrence. T2MRI images will be most accurate in the correct diagnosis of Surgicel.

Acute cerebral hemorrhage mimicking glioblastoma on intraoperative magnetic resonance imaging: A case report

Intraoperative magnetic resonance imaging (iMRI) is important in neurosurgical practice, especially for glioma surgery. However, the well-reported possibility to mistake lesions for brain tumors (tumor mimics) with MRI also exists for iMRI. Here, we first report a case of glioblastoma with acute cerebral hemorrhage that mimicked a newly emerged brain tumor on iMRI. A 53-year-old man underwent a second surgery for recurrent glioblastoma. Intraoperatively, iMRI revealed a new, enhanced lesion near the resected area that was absent on preoperative MRI and difficult to differentiate from newly emerged tumors. Here, a recent preoperative MRI was helpful and the new lesion was actually a hematoma. Neurosurgeons must understand that, as acute intracerebral hemorrhaging can mimic brain tumors on iMRI, preoperative MRI should be conducted just before surgery to place iMRI findings in proper context and avoid unnecessary resections.

Significance of Early Postoperative Magnetic Resonance Imaging following Intracranial Meningioma Resection

The significance of early postoperative magnetic resonance imaging (MRI) for meningioma resection has not yet been evaluated. We retrospectively reviewed patients with intracranial meningiomas resected at our institute between 2011 and 2021. Early postoperative MRI with contrast enhancement was routinely performed within 48 h after surgery while first follow-up MRI was performed approximately after 6 months. MRI findings were reviewed, and the risk factors for postoperative infarction and early recurrence were analyzed. Among the 245 resections performed, early postoperative MRI was performed in 200 cases. Postoperative radiological and symptomatic infarctions occurred in 54 (27%) and 17 patients (9%), respectively. Diameter > 5 cm (p = 0.015) and skull base location (p = 0.010) were independent risk factors for radiological infarctions. Follow-up postoperative MRI performed in 180 patients (90%) detected early recurrence in 24 patients (13%). Non-gross total resection was an independent risk factor for early recurrence (p < 0.0001). Additionally, early recurrence after gross total resection occurred significantly more frequently in meningiomas with dural sinus involvement than in those without (8.3% vs. 0%, p = 0.018). Thus, early postoperative MRI may enable the timely assessment of postoperative neurological deficits, especially after large skull base meningioma resections along with accurate detection of early recurrence, which is critical for meningiomas with dural sinus involvement.

MRI appearance of adjunct surgical material used in spine surgery

BACKGROUND CONTEXT

Early postoperative MR images are frequently necessary after spine surgery. The appearance of commonly used adjunct hemostatic agents and dural sealants in MR images has not been systematically evaluated.

PURPOSE

The purpose of this experimental study was to systematically analyze and describe the characteristics of the most commonly applied hemostatic agents and dural sealants in spine surgery on early postoperative MR images.

STUDY DESIGN

Cadaver Study METHODS: Four commonly applied dural sealants (Duraseal, Bioglue, Tachosil, Tisseel) and five commonly used hemostatic agents (Surgiflo, Bonewax, , Spongostan, Gelfoam, Avitene) were investigated. The experimental setting involved a human cadaver where a standard left-sided laminotomy was performed on nine levels of the thoracolumbar spine, and the materials were separately applied and mixed with fresh blood or water for hemostatic and dural sealants, respectively. The cadaver model was scanned at a 3 Tesla MRI and the imaging findings for all materials were compared to the surrounding tissue and systematically reported.

RESULTS

All investigated dural sealants and hemostatic agents were distinguishable from the surrounding tissue on MR images with different appearances on the MR sequences. A detailed atlas for the identification of the materials in postoperative spine MRI was established.

CONCLUSION

Commonly used hemostatic agents and dural sealants can be successfully identified on early postoperative spine MRI.

CLINICAL SIGNIFICANCE

Knowledge about MRI appearances of commonly used adjunct surgical materials helps in interpretation of postoperative imaging and supports clinical decision making.

Reactive gliosis mimicking tumor recurrence - a case series documenting MRI abnormalities and neuropathological correlates

Abstract. The aim of this study is to identify, in our center, all cases of foreign-body reactions to hemostatic agents or other prostheses resulting in a radiological suspicion of tumor recurrence. We interrogated our internal database to identify all such cases and systematically evaluated the MRI brain scans of patients: (i) at the time of initial tumor diagnosis, (ii) postoperatively, (iii) and at the time of suspected tumor recurrence. In addition, we reviewed each patient’s operative notes and reviewed the histology of all cases following a second surgical intervention. In total, we identified 8 patients, 7 of whom had a WHO grade II glioma at initial surgery. We did not identify any distinguishing radiological abnormalities from the initial diagnostic brain scan to the suspected recurrence, and histologically all cases were characterized by extensive gliosis; with both macrophages and reactive astrocytes present throughout. The cause of gliosis was identified as being relating to hemostatic agents in 4 cases; in the other 4 cases, the foreign-body reaction was presumed to be caused be materials used in a craniotomy or cranioplasty. This study highlights the difficulty in radiologically diagnosing a foreign-body reaction and also identifies that such a gliotic reaction may occur as a consequence of exogenous materials used in a craniotomy or cranioplasty.

Magnetic Resonance Imaging Appearance and Mechanism of Action of Five Hemostatic Agents Used in Neurosurgery

OBJECTIVE

To describe the magnetic resonance (MR) image appearance of 5 hemostatic agents placed in the brain, and to review their clinical application.

STUDY DESIGN

Descriptive ex vivo and in vivo study.

ANIMALS

Canine cadavers (n=4), client-owned dogs (n=4).

METHODS

Heads from 4 canine cadavers were used, each with 5 hemostatic agents placed in specific locations in the brain. Hemostatic agents were used in their native form in 2 cadaveric brains, and in 2 others the materials were saturated with fresh whole blood prior to placement to mimic application in a field of active hemorrhage. The heads underwent MR imaging and the images were reviewed. Postoperative MRI images from 4 dogs undergoing brain tumor resection were retrospectively reviewed and compared to the images from the cadavers. All clinical cases and cadaveric specimens underwent surgical closure prior to MR imaging including placement of titanium mesh over the craniotomy defect with a dural graft of porcine small intestinal submucosa (SIS) sealed with Tisseel (fibrin sealant).

RESULTS

The SIS and Tisseel used in the dural graft were consistently indistinguishable from the surrounding tissues on MR images. The MR imaging appearance of the remaining 4 hemostatic agents (Gelfoam, Avitene, Surgicel, and Floseal) placed on the surface or in the parenchyma of canine brain, varied with MR sequence weighting and blood saturation.

CONCLUSION

Accurate evaluation of the degree of brain tumor resection on postoperative MR images requires careful differentiation between hemorrhage, residual tumor, and hemostatic agents implanted.

Clinical applications of iron oxide nanoparticles for magnetic resonance imaging of brain tumors

Current neuroimaging provides detailed anatomic and functional evaluation of brain tumors, allowing for improved diagnostic and prognostic capabilities. Some challenges persist even with today's advanced imaging techniques, including accurate delineation of tumor margins and distinguishing treatment effects from residual or recurrent tumor. Ultrasmall superparamagnetic iron oxide nanoparticles are an emerging tool that can add clinically useful information due to their distinct physiochemical features and biodistribution, while having a good safety profile. Nanoparticles can be used as a platform for theranostic drugs, which have shown great promise for the treatment of CNS malignancies. This review will provide an overview of clinical ultrasmall superparamagnetic iron oxides and how they can be applied to the diagnostic and therapeutic neuro-oncologic setting.

Imaging features of a gelatin-thrombin matrix hemostatic agent in the intracranial surgical bed: a unique space-occupying pseudomass

BACKGROUND AND PURPOSE

Absorbable gelatin-thrombin matrix is increasingly being used in neurosurgical procedures; unlike other hemostats, the stable matrix is left undisturbed and fills the surgical bed after achieving hemostasis. We investigated the immediate postoperative radiographic imaging appearance of the gelatin-thrombin matrix in intracranial operative beds.

MATERIALS AND METHODS

Thirty-one consecutive patients (18 men, 13 women; mean age, 59 years) with 34 surgical cavities, had 31 brain MRIs and 9 head CTs performed ≤ 48 hours postoperatively. They were retrospectively reviewed. Images were evaluated independently by 2 neuroradiologists blinded to the surgical techniques. Surgical beds were evaluated for the presence of the gelatin-thrombin matrix, which appeared as pseudoair material (Hounsfield units ≤ -100) on CT, had characteristic T2-hypointense speckles in a T2-hyperintense background, and demonstrated complete gradient-recalled echo hypointensity on MR imaging. To determine the diagnostic performance of imaging features for the detection of the gelatin-thrombin matrix, the Fisher exact test for the association between imaging features and the presence of the gelatin-thrombin matrix and κ analysis for interobserver agreement were performed.

RESULTS

Hemostasis was achieved with standard methods in 12 surgical beds and with the gelatin-thrombin matrix in 22 beds. Interobserver agreement was substantial. The gelatin-thrombin matrix demonstrated pseudoair hypoattenuation (88% sensitivity, 100% specificity, 90% accuracy; P = .067, κ = 0.74) and distinctive T2-hypointense speckles in a background of T2-hyperintensity (81% sensitivity, 85% specificity, 82% accuracy; P = <.001, κ = 0.76). Combined characteristic T2 speckles and gradient-recalled echo hypointensity increased the specificity (81% sensitivity, 100% specificity, 88% accuracy; P = < .001).

CONCLUSIONS

The unique appearance (pseudoair on CT, T2 speckles with gradient-recalled echo hypointensity) of the gelatin-thrombin matrix should not be mistaken for gossypiboma, pneumocephalus, and/or hematoma.

Cerebral blood flow quantification in swine using pseudo-continuous arterial spin labeling

PURPOSE

To develop quantitative cerebral blood flow (CBF) imaging using pseudo-continuous arterial spin labeling (PCASL) in swine, accounting for their cerebrovascular anatomy and physiology.

MATERIALS AND METHODS

Five domestic pigs (2.5-3 months, 25 kg) were used in these studies. The orientation of the labeled arteries, T1bl , M0bl , and T1gm were measured in swine. Labeling parameters were tuned with respect to blood velocity to optimize labeling efficiency based on the data collected from three subjects. Finally, CBF and arterial transit time (ATT) maps for two subjects were created from PCASL data to determine global averages.

RESULTS

The average labeling efficiency over measured velocities of 5-18 cm/s was 0.930. The average T1bl was 1546 ms, the average T1gm was 1224 ms, and the average blood-to-white matter ratio of M0 was 1.25, which was used to find M0bl . The global averages over the subjects were 54.05 mL/100 g tissue/min CBF and 1261 ms ATT.

CONCLUSION

This study demonstrates the feasibility of PCASL for CBF quantification in swine. Quantification of CBF using PCASL in swine can be further developed as an accessible and cost-effective model of human cerebral perfusion for investigating injuries that affect blood flow.

Use of intraoperative MRI for resection of gliomas

Literature has shown that extent of tumor resection has an impact on quality of life and survival of patients with gliomas. Intraoperative MRI has been used to increase resection while preserving procedure's safety. METHOD: The first five patients with gliomas operated on at the University of São Paulo using intraoperative MRI are reported. All but one patient had Karnofsky Performance Status of 100% before surgery. Presentation symptoms were progressive headache, seizures, behavior disturbance, one instance of hemianopsia, and another of hemiparesis. RESULTS: Gross total removal was achieved in two patients. Surgical resection was limited by tumor invasion of critical areas like the internal capsule or the mesencephalon in the remaining patients. CONCLUSION: Intra-operative MRI is an important tool that helps surgeons to remove glial tumors, however, knowledge of physiology and functional anatomy is still fundamental to avoid morbidity.

Prevention of adhesion formation following ovarian surgery in a standardized animal model: comparative study of Interceed and double layer Surgicell

AIM

Comparison of antiadhesive performances of double layer Surgicell and single layer Interceed following ovarian surgery in a rabbit model.

METHODS

Prospective randomized controlled trial performed at the animal laboratory of a university. Thirty-nine New Zealand White female rabbits of reproductive age were included. Ovaries were bivalved with a no. 15 scalpel. One of the ovaries was covered with a single layer of Interceed while the other was covered with a double layer of Surgicell. In the control group no adhesion barriers were used. Four weeks later adhesions were scored macroscopically. Following oophorectomy specimens were evaluated microscopically for mesothelial proliferation. The macroscopic adhesion score according to Blauer's criteria and the number of mesothelial cell layers were compared.

RESULTS AND CONCLUSION

The control group had significantly higher adhesion scores than the barrier groups. Macroscopic adhesion scores were not different among the barrier groups. The average number of mesothelial cell layers was 1.77+/-2.68, 1.69+/-2.58 (range 0-8) and 2.04+/-2.84 (range 0-10) for ovaries in the control, Interceed and Surgicell groups, respectively: the difference was not significant. Our results demonstrate that a double layer of Surgicell is as effective as Interceed in reducing postoperative adhesion formation in a rabbit model.

The potential of ferumoxytol nanoparticle magnetic resonance imaging, perfusion, and angiography in central nervous system malignancy: a pilot study

OBJECTIVE

Ferumoxytol, an iron oxide nanoparticle that targets phagocytic cells, can be used in magnetic resonance imaging of malignant brain tumors and can be administered as a bolus, allowing dynamic imaging. Our objectives were to determine the optimum time of delayed contrast enhancement of ferumoxytol, and to compare ferumoxytol and gadolinium contrast agents for magnetic resonance angiography and perfusion.

METHODS

Twelve patients with malignant brain tumors underwent serial magnetic resonance imaging multiple times up to 72 hours after ferumoxytol injection at both 1.5 and 3-T. The enhancement time course was determined for ferumoxytol and compared with a baseline gadolinium scan. Perfusion, time-of-flight and dynamic magnetic resonance angiography and T1-weighted scans were compared for the two agents.

RESULTS

The lesions were detectable at all field strengths, even with an intraoperative 0.15-T magnet. Maximal ferumoxytol enhancement intensity was at 24 to 28 hours after administration, and the enhancing volume subsequently expanded with time into a non-gadolinium-enhancing, high T2-weighted signal region of tumor-infiltrated brain. Dynamic studies were assessed with both agents, indicating early vascular leak with gadolinium but not with ferumoxytol.

CONCLUSION

Our most important finding was that gadolinium leaks out of blood vessels early after injection, whereas ferumoxytol stays intravascular in the "early" phase, thereby increasing the accuracy of tumor perfusion assessment. As a magnetic resonance imaging contrast agent, ferumoxytol visualizes brain tumors at all field strengths evaluated, with delayed enhancement peaking at 24 to 28 hours after administration.

Clinical benefits and risk analysis of topical hemostats: a review

A variety of local hemostats including absorbable gelatin sponge, collagen hemostat, and oxidized cellulose are commercially available. Local hemostats are applied when cautery, ligature, or other conventional hemostatic method is impractical. Proper handling is essential to control bleeding and only the required amount should be used, even though the hemostat is expected to dissolve promptly. A dry local hemostat absorbs body fluid of several times its own weight and expands postoperatively. Therefore, when an absorbable hemostatic agent is retained on or near bony or neural spaces, the minimum amount should be left after hemostasis is achieved. Documentation is important with regard to the hemostat used, including the name of the agent, site, and amount. This information is used as a reference in the interpretation of postoperative diagnostic images, since retained hemostat may sometimes mimic an abscess or recurrent tumor. The antigenicity of collagen is known to be low because of homology. When the safety of collagen was evaluated, the incidence of positive reactions was reported as 3.0%, and collagen may cause allergic reactions. Minimum inflammation without strong foreign body reactions or blockade of healing is desirable after the use of local hemostats. Strong foreign body reactions, chronic inflammation, and infections can cause granuloma formation after local hemostat use. By using local hemostats, it is possible to improve the condition of the patient, reduce complications, and lower direct and indirect costs.

Radiological and histopathological examination of early tissue reactions to absorbable hemostatic agents in the rabbit brain

Topical hemostatic agents are widely and safely used in neurosurgery. The purpose of this study was to compare and analyse the early tissue reactions to two hemostatic agents, oxidized regenerated cellulose and gelatin sponge, in rabbit brain by magnetic resonance imaging and histopathologic sections. Bilateral identical parenchymal lesions were made in the frontal regions of each hemisphere in 13 rabbits. Hemostasis was achieved using oxidized regenerated cellulose or gelatin sponge, one agent being used on each side. Cranial magnetic resonance imaging was performed 24 h postoperatively and there was no statistical difference in edema formation at the site of the lesions. Histopathologic examinations indicated that pericapillary edema and endothelial distortion were common in both groups but that there was additional tissue degeneration evident in the regions where gelatin sponge had been used. Oxidized regenerated cellulose seemed to cause greater tissue distortion in magnetic resonance images than gelatin sponge but in contrast, histological examination of lesions in which oxidized regenerated cellulose had been used revealed less tissue degeneration than histopathologic examinations of lesions in which gelatin sponge had been used.

Imaging of iron oxide nanoparticles by MR and light microscopy in patients with malignant brain tumours

OBJECTIVE

Ferumoxtran-10 (Combidex), a dextran-coated iron oxide nanoparticle, provides enhancement of intracranial tumours by magnetic resonance (MR) for more than 24 h and can be imaged histologically by iron staining. Our goal was to compare ferumoxtran imaging and histochemistry vs. gadolinium enhancement in malignant brain tumours on preoperative and postoperative MR.

METHODS

Seven patients with primary and metastatic malignant tumours underwent MR imaging with gadolinium and ferumoxtran both pre- and postoperatively. Normalized signal intensities on the ferumoxtran-enhanced scans were determined in representative regions of interest. Resected tissue from six ferumoxtran patients and from three patients who did not receive ferumoxtran was assessed for localization of iron in tumour and reactive brain.

RESULTS

All malignant tumours (all of which enhanced by gadolinium MR) showed ferumoxtran accumulation with T1 and T2 signal changes, even using a 0.15 T intraoperative MR unit in one patient. Iron staining was predominantly in reactive cells (reactive astrocytes and macrophages) and not tumour cells. In five of the seven patients, including two patients who showed additional lesions, areas enhancing with ferumoxtran but not with gadolinium were observed. Comparison of the pre- and postoperative MR revealed residual ferumoxtran-enhancing areas in four of seven cases.

CONCLUSION

In malignant tumours, ferumoxtran may show areas of enhancement, even with a 0.15 T intraoperative MR, that do not enhance with gadolinium. Ferumoxtran-enhancing lesions have persistent increased T1 signal intensity for 2-5 days, which may provide advantages over gadolinium for postoperative imaging. Histochemistry for iron shows uptake of ferumoxtran in reactive cells (astrocytes and macrophages) rather than tumour cells.

Laparoscopic oxidized cellulose (Surgicel) application for small uterine perforations

OBJECTIVES

To test the efficacy and safety of laparoscopic oxidized cellulose application at the uterine perforation site.

METHODS

In a prospective study over a 3.5-year period a total of 30 women undergoing combined surgical termination of pregnancy and laparoscopic sterilization who had a small uterine perforation were recruited. Oxidized cellulose (Surgicel) was inserted and attached to the perforation site with a laparoscope. The end point was sealing of the perforation and complete hemostasis. Laparotomy was performed if hemostasis was not achieved.

RESULTS

The mean age, parity and gestation were 31.4 years, 3.8 and 9.3 weeks. The perforations occurred in the fundal region (60%), anterior wall (16.7%), posterior wall (13.3%), upper lateral wall (3.3%) and lower lateral wall (6.7%). Mean size of perforations, respectively according to site were 4.3 mm, 3.2 mm, 3.4 mm, 3 mm and 3.5 mm in the five groups. Laparoscopic oxidized cellulose application was successful in all women with fundal, anterior, posterior and upper lateral uterine wall perforations. In two women with perforations on the lower lateral wall, due to excessive blood loss, oxidized cellulose fell off; laparotomy was performed and hemostasis was achieved with sutures. All 28 laparoscopically-treated women were discharged on the next day in good condition with no complications.

CONCLUSIONS

Laparoscopic oxidized cellulose application appears to be a safe and effective treatment for small uterine perforations that are bleeding moderately.