Imaging of Ventriculoperitoneal Shunt Complications: Comparison of Whole Body Low-Dose Computed Tomography and Radiographic Shunt Series.

OBJECTIVE: To determine diagnostic value and radiation exposure of low-dose computed tomography (LD-CT) compared to radiographic shunt series (SS) for the detection of ventriculoperitoneal (VP) shunt complications. METHODS: Fourteen VP shunts were implanted in 7 swine cadavers. Mechanical complications were induced in 50% of VP shunts. Low-dose CT (80 kVp, 10 mAs, Pitch = 1.5) and SS were acquired. Dose area product (DAP) and effective doses for SS and LD-CT were collected. Scoring of diagnostic confidence and blinded readings of SS and CT data were performed. RESULTS: The sensitivity of LD-CT was high (0.97; 95% confidence interval, 0.91-1.00) with excellent interobserver agreement (κ = 0.88). Similarly, the sensitivity of SS was high (0.82; 95% confidence interval, 0.68-0.95) with good interobserver agreement (κ = 0.68). In contrast, LD-CT was associated with significantly higher diagnostic confidence (4.64 ± 0.41 vs 2.71 ± 0.73; P < 0.01) and significantly lower radiation exposure (effective dose: 0.26 mSv vs 1.06 mSv; DAP: 265.4 µGym vs 724.8 µGym; P < 0.001). CONCLUSIONS: For the assessment of suspected VP shunt complications, LD-CT provides excellent sensitivity and higher diagnostic confidence with lower radiation exposure compared with SS.

Evaluation of whole body Ultralow-Dose CT for the assessment of ventriculoperitoneal shunt complications: an experimental ex-vivo study in a swine model.

OBJECTIVE: To evaluate the suitability of whole body Ultralow-dose CT (ULD-CT) as a diagnostic tool for the evaluation of ventriculoperitoneal shunt (VP-shunt) complications with special regards to radiation dose and image quality. METHODS: Fourteen VP-shunts were implanted in 7 swine cadavers (weight: 55-70 kg). Twenty-two mechanical complications (extracranial and extraperitoneal malpositioning, breakages, disconnections) were induced in nine VP-shunts. Ten ULD-CT scans with different parameters (tube voltage: 80, 100, 120 kV; tube current: 20 or 50 mAs; Pitch (P): 1 or 1.5) were acquired; the combination of 120 kV and 50 mAs was omitted. Radiation dose estimation, blinded readings, and quantitative and qualitative assessment of the CT-data were performed. RESULTS: Effective radiation doses varied between 0.44 ± 0.06 and 2.55 ± 0.35 mSv. ULD-CT protocols provided a mean sensitivity (i.e., correctly detected shunt complications) of 98.2 %. Unnoticed or incorrectly identified complications did not exceed one complication (4.5 %) in any ULD-CT protocol. Diagnostic confidence was sufficient for all ULD-CT protocols except for protocols with 80 kV and 20 mAs. CONCLUSIONS: ULD-CT allows accurate detection of VP-shunt complications at radiation doses similar or lower than reported for a radiographic shunt series. At the tested radiation dose levels, ULD-CT thus provides an alternative to a radiographic shunt series. KEY POINTS: • Ultralow-dose CT accurately detects Ventriculoperitoneal Shunt complications. • Radiation dosage is similar or lower than reported for a radiographic shunt series. • Ultralow-dose CT potentially shortens the diagnostic process when shunt complications are suspected.

Chronic Subdural Hematoma.

BACKGROUND: Chronic subdural hematoma (cSDH) is typically a disease that affects the elderly. Neurosurgical evacuation is generally indicated for hematomas that are wider than the thickness of the skull. The available guidelines do not address the common clinical issue of the proper management of antithrombotic drugs that the patient has been taking up to the time of diagnosis of the cSDH. Whether antithrombotic treatment should be stopped or continued depends on whether the concern about spontaneous or postoperative intracranial bleeding, and a presumably higher rate of progression or recurrence, with continued medication outweighs the concern about a possibly higher rate of thrombotic complications if it is stopped. METHODS: In this article, we review publications from January 2015 to October 2020 addressing the issue of the management of antithrombotics in patients with cSDH that were retrieved by a selective search in the Pubmed and EMBASE databases, and we present the findings of a cohort study of 395 patients who underwent surgery for cSDH consecutively between October 2014 and December 2019. RESULTS: The findings published in the literature are difficult to summarize concisely because of the heterogeneity of study designs. Among the seven studies in which a group of patients on antithrombotics was compared with a control group, four revealed significant differences with respect to the risk of thromboembolic complications depending on previous antithrombotic use and the duration of discontinuation, while three others did not. In our own cohort, discontinuation of antithrombotics (including both plasmatic and antiplatelet drugs) was associated with thrombotic complications in 9.1% of patients. CONCLUSION: These findings imply that the management of antithrombotics should be dealt with critically on an individual basis. In patients with cSDH who are at elevated risk, an early restart of antithrombotic treatment or even an operation under continued antithrombotic therapy should be considered.

High-Pitch Low-Dose Whole-Body Computed Tomography for the Assessment of Ventriculoperitoneal Shunts in a Pediatric Patient Model: An Experimental Ex Vivo Study in Rabbits.

OBJECTIVE: The aim of this study was to assess the diagnostic value of whole-body low-dose (LD) computed tomography (CT) for the detection of ventriculoperitoneal (VP) shunt complications in pediatric patients compared with radiographic shunt series (SS) in an ex vivo rabbit animal model. METHODS: In the first step, 2 optimized LD-CT imaging protocols, with high pitch (pitch, 3.2), low tube voltages (70 kVp and 80 kVp), and using both filtered back projection and iterative reconstruction, were assessed on a 16-cm solid polymethylmethacrylate phantom regarding signal-to-noise ratio and radiation dose. Taking both radiation dose and signal-to-noise ratio into account, the LD-CT protocol (80 kVp; 4 mA; pitch, 3.2) was identified as most appropriate and therefore applied in this study.After identification of appropriate LD-CT protocol, 12 VP shunts were implanted in 6 rabbit cadavers (mean weight, 5.1 kg). Twenty-four mechanical complications (extracranial and extraperitoneal malpositioning, breakages, and disconnections) were induced in half of the VP shunts. Low-dose CT and conventional SS were acquired in standard fashion. Dose-area products (DAPs) for SS and LD-CT were collected; effective radiation doses for both SS and LD-CT were estimated using CT-Expo (v. 2.3.1.) and age-specific effective dose (ED) estimates. Qualitative scoring of diagnostic confidence on a 5-point Likert scale (1, very low diagnostic confidence; 5, excellent diagnostic confidence) and blinded readings of both SS and LD-CTs were performed. RESULTS: Among the 24 VP shunt complications, LD-CT yielded excellent sensitivity and specificity for the detection of VP shunt complications (sensitivity, 0.98; specificity, 1; 95% confidence interval, 0.92-1) with excellent interobserver agreement (κ = 0.90). Shunt series yielded good sensitivity and specificity (sensitivity, 0.75; specificity, 1; 95% confidence interval, 0.58-0.92) with moderate interobserver agreement (κ = 0.56). No false-positive findings were registered. Compared with SS, LD-CT yielded significantly lower ED and DAPs (ED, 0.039 vs 0.062 mSv; DAP, 20.5 vs 26.3; P < 0.05). CONCLUSIONS: In this experimental ex vivo pediatric patient model, LD-CT yields excellent sensitivity for the detection of VP shunt complications at higher diagnostic confidence and lower radiation exposure compared with SS.