Steven Raeymaeckers

Purpose: To assess the performance of the inferior lateral ventricle (ILV) to hippocampal (Hip) volume ratio on brain MRI, for Alzheimer’s disease (AD) diagnostics, comparing it to individual automated ILV and hippocampal volumes, and visual medial temporal lobe atrophy (MTA) consensus ratings. Methods: One-hundred-twelve subjects (mean age ± SD, 66.85 ± 13.64 years) with varying degrees of cognitive decline underwent MRI using a Philips Ingenia 3T. The MTA scale by Scheltens, rated on coronal 3D T1-weighted images, was determined by three experienced radiologists, blinded to diagnosis and sex. Automated volumetry was computed by icobrain dm (v. 5.10) for total, left, right hippocampal, and ILV volumes. The ILV/Hip ratio, defined as the percentage ratio between ILV and hippocampal volumes, was calculated and compared against a normative reference population (n = 1903). Inter-rater agreement, association, classification accuracy, and clinical interpretability on patient level were reported. Results: Visual MTA scores showed excellent inter-rater agreement. Ordinal logistic regression and correlation analyses demonstrated robust associations between automated brain segmentations and visual MTA ratings, with the ILV/Hip ratio consistently outperforming individual hippocampal and ILV volumes. Pairwise classification accuracy showed good performance without statistically significant differences between the ILV/Hip ratio and visual MTA across disease stages, indicating potential interchangeability. Comparison to the normative population and clinical interpretability assessments showed commensurability in classifying MTA “severity” between visual MTA and ILV/Hip ratio measurements. Conclusion: The ILV/Hip ratio shows the highest correlation to visual MTA, in comparison to automated individual ILV and hippocampal volumes, offering standardized measures for diagnostic support in different stages of cognitive decline.

Background: Patients with advanced melanoma who progress after treatment with immune checkpoint-inhibitors (ICI) and BRAF-/MEK-inhibitors (if BRAF ^V600 mutated) have no remaining effective treatment options. The presence of CD1c (BDCA-1)⁺ and CD141 (BDCA-3)⁺ myeloid dendritic cells (myDC) in the tumor microenvironment correlates with pre-existing immune recognition and responsiveness to immune checkpoint blockade. The synthetic saponin-based immune adjuvant AS01_B enhances adaptive immunity through the involvement of myDC. Methods: In this first-in-human phase I clinical trial, patients with metastatic melanoma refractory to ICI and BRAF-/MEK inhibitors (when indicated) were recruited. Patients received an intravenous administration of low-dose nivolumab (10 mg, every 2 weeks) plus an intratumoral (IT) administration of 10 mg ipilimumab and 50 µg (0.5 mL) AS01_B (every 2 weeks). All myDC, isolated from blood, were injected on day 2 into the same metastatic lesion. Tumor biopsies and blood samples were collected at baseline and repeatedly on treatment. Multiplex immunohistochemistry (mIHC) was performed on biopsy sections to characterize and quantify the IT and peritumoral immune cell composition. Results: Study treatment was feasible and well tolerated without the occurrence of unexpected adverse events in all eight patients. Four patients (50%) obtained a complete response (CR) in the injected lesions. Of these, two patients obtained an overall CR, and one patient a partial response. All responses are ongoing after more than 1 year of follow-up. One additional patient had a stable disease as best response. The disease control rate was 50%. Median progression-free survival and overall survival were 24.1 and 41.9 weeks, respectively. Baseline tumor biopsies from patients who responded to treatment had features of T-cell exclusion. During treatment, there was an increased T-cell infiltration, with a reduced mean distance between T cells and tumor cells. Peripheral blood immune cell composition did not significantly change during study treatment. Conclusions: Combining an intratumoral injection of CD1c (BDCA-1)⁺ and CD141 (BDCA-3)⁺ myDC with repeated IT administration of ipilimumab and AS01_B and systemic low-dose nivolumab is safe, feasible with promising early results, worthy of further clinical investigation. Trial registration number: ClinicalTrials.gov identifier NCT03707808.

We report the case of a 72-year-old patient presenting with recurrent primary hyperparathyroidism after total thyroidectomy and parathyroidectomy with presternal autotransplantation. Methionine-PET-CT proved false-positive and Tc-99m-tetrofosmine imaging false-negative. Using a novel multiphase-4DCT technique we identified an anterior mediastinal nodule demonstrating contrast wash-in and wash-out, suggesting parathyroid adenoma. Traditional 4DCT-protocols obtain fewer phases; therefore, this enhancement pattern might have gone unnoticed. After surgical resection the bloodwork normalized, histopathology confirmed a parathyroid adenoma. Multiphase 4DCT is a potentially helpful technique for the detection of parathyroid adenomas after total thyroidectomy and parathyroidectomy.

Background: The literature considers sclerotherapy to be a safe and effective treatment for benign thyroid cysts. No subsequent diagnostic problems have been reported as a complication. We report the occurrence of focal inflammation after said therapy, mimicking a thyroid malignancy. Case presentation: We report a case of a young male with a solitary strongly suspicious lesion in the thyroid. The patient had undergone prior sclerotherapy of a thyroid cyst with Doxycycline. The lesion appeared to be a focal area of inflammation and thus iatrogenic in nature. Systemic use of doxycycline is known to sometimes cause a non-immune chemical thyroiditis, dubbed as black thyroid due to the intense black discoloration of the thyroid. It might be that the instillation of doxycycline was responsible for a similar, more localized area of thyroiditis. Conclusions: For the work-up of a solitary suspicious thyroid lesion, the medical history of the patient should always be considered. In case of prior ipsilateral sclerotherapy, a reactive inflammatory response may mimic thyroid malignancy. A fine needle aspiration should be performed to exclude thyroid cancer. Treatment is not necessary; the process appears to be self-limiting as evidenced in the follow-up of this case.

A multiphase 4DCT technique can be useful for the detection of parathyroid adenomas. Up to 16 different phases can be obtained without significant increase of exposure dose using wide beam axial scanning. This technique also allows for the calculation of perfusion parameters in suspected lesions. We present data on 19 patients with histologically proven parathyroid adenomas. We find a strong correlation between 2 perfusion parameters when comparing parathyroid adenomas and thyroid tissue: parathyroid adenomas show a 55% increase in blood flow (BF) ( p < 0.001 ) and a 50% increase in blood volume (BV) ( p < 0.001 ) as compared to normal thyroid tissue. The analysis of the ROC curve for the different perfusion parameters demonstrates a significantly high area under the curve for BF and BV, confirming these two perfusion parameters to be a possible discriminating tool to discern between parathyroid adenomas and thyroid tissue. These findings can help to discern parathyroid from thyroid tissue and may aid in the detection of parathyroid adenomas.

Background: The literature considers sclerotherapy to be a safe and effective treatment for benign thyroid cysts. No subsequent diagnostic problems have been reported as a complication. We report the occurrence of focal inflammation after said therapy, mimicking a thyroid malignancy.Case presentation: We report a case of a young male with a solitary strongly suspicious lesion in the thyroid. The patient had undergone prior sclerotherapy of a thyroid cyst with Doxycycline. The lesion appeared to be a focal area of inflammation and thus iatrogenic in nature. Systemic use of doxycycline is known to sometimes cause a non-immune chemical thyroiditis, dubbed as black thyroid due to the intense black discoloration of the thyroid. It might be that the instillation of doxycycline was responsible for a similar, more localized, process of affliction.Conclusions: For the work-out of a solitary suspicious thyroid lesion, the medical history of the patient should always be considered. In case of antecedents of ipsilateral sclerotherapy, a reactive inflammatory response may mimic thyroid malignancy. A fine needle aspiration should be performed to exclude thyroid cancer. Treatment is not necessary; the affliction appears self-limiting as evidenced in the follow-up of this case.

Not all causes of subcutaneous emphysema are attributable to necrotizing fasciitis. Consider other causes of subcutaneous emphysema in the differential diagnosis.

4-Dimensional computed tomography (4DCT) for the detection of (an) enlarged parathyroid(s) is a commonly performed examination in the management of primary hyperparathyroidism. In our center, we introduced a high-frequency multiphase 4DCT protocol obtaining 16 phases, including 11 different arterial phases. Exposure to this multiphase 4DCT technique is similar to that for classic helical 4DCT. In this pictorial essay we reconstructed our multiphase 4DCT series in the manner of a classic helical 4DCT and compare both techniques. We illustrate how multiphase 4DCT may aid in the detection of parathyroid adenomas. We found 17 out of 19 lesions demonstrating a type A pattern of enhancement, therefore suggesting this pattern could be more prevalent than previously thought. Some parathyroid adenomas may be mistaken for enlarged lymph nodes using classic 4DCT whereas high-frequency multiphase 4DCT can detect a temporary rise in enhancement, thus suggesting the lesions in question to be of parathyroid origin. Smaller lesions may prove more obvious as the difference in enhancement between parathyroid and thyroid can become more prominent. Key Point: Using high-frequency multiphase 4DCT an arterial phase with maximum enhancement of parathyroid tissue can be defined. This phase may aid in the detection of parathyroid adenomas.

Objective. 4DCT for the detection of (an) enlarged parathyroid(s) is a commonly performed examination in the management of primary hyperparathyroidism. Protocols are often institution-specific; this review aims to summarize the different protocols and explore the reported sensitivity and specificity of different 4DCT protocols as well as the associated dose. Materials and Methods. A literature study was independently conducted by two radiologists from April 2020 until May 2020 using the Medical Literature Analysis and Retrieval System Online (MEDLINE) database. Articles were screened and assessed for eligibility. From eligible studies, data were extracted to summarize different parameters of the scanning protocol and observed diagnostic attributes. Results. A total of 51 articles were included and 56 scanning protocols were identified. Most protocols use three (n=25) or four different phases (n=23). Almost all authors include noncontrast enhanced imaging and an arterial phase. Arterial images are usually obtained 2530s after administration of contrast, and less agreement exists concerning the timing of the venous phase(s). A mean contrast bolus of 100mL is administered at 3-4mL/s. Bolus tracking is not often used (n=3). A wide range of effective doses are reported, up to 28mSv. A mean sensitivity of 81.5 and a mean specificity of 86 are reported. Conclusion. Many different 4DCT scanning protocols for the detection of parathyroid adenomas exist in the literature. The number of phases does not appear to affect sensitivity or specificity. A triphasic approach, however, seems preferable, as three patterns of enhancement of parathyroid adenomas are described. Bolus tracking could help to reduce the variability of enhancement. Sensitivity and specificity also do not appear to be affected by other scan parameters like tube voltage or tube current. To keep the effective dose within limits, scanning at a lower fixed tube current seems preferable. Lowering tube voltage from 120kV to 100kV may yield similar image contrast but would also help lower the dose.

Background: Four-dimensional computed tomography (4DCT) is a commonly performed examination in the management of primary hyperparathyroidism, combining three-dimensional imaging with enhancement over time as the fourth dimension. We propose a novel technique consisting of 16 different contrast phases instead of three or four different phases. The main aim of this study was to ascertain whether this protocol allows the detection of parathyroid adenomas within dose limits. Our secondary aim was to examine the enhancement of parathyroid lesions over time. Methods: For this prospective study, we included 15 patients with primary hyperparathyroidism and a positive ultrasound prior to surgery. We performed 4DCT with 16 different phases: an unenhanced phase followed by 11 consecutive arterial phases and 4 venous phases. Continuous axial scanning centered on the thyroid was performed over a fixed 8 cm or 16 cm coverage volume after the start of contrast administration. Results: In all patients, an enlarged parathyroid lesion was demonstrated, and the mean lesion size was 13.6 mm. The mean peak arterial enhancement for parathyroid lesions was 384 Hounsfield units (HU) compared to 333 HU for the normal thyroid. No significant difference could be found. The time to peak (TTP) was significantly earlier for parathyroid adenomas than for normal thyroid tissue: 30.8 s versus 32.3 s (p value 0.008). The mean slope of increase (MSI) of the enhancement curve was significantly steeper than that of normal thyroid tissue: 29.8% versus 22.2% (p value 0.012). The mean dose length product was 890.7 mGy cm with a calculated effective dose of 6.7 mSv. Conclusion: Our 4DCT protocol may allow better visualization of the pattern of enhancement of parathyroid lesions, as enhancement over time curves can be drawn. In this way, wash-in and wash-out of contrast in suspected lesions can be readily demonstrated. Motion artifacts are less problematic as multiple phases are available. Exposure to our proposed 4DCT technique is comparable to that for classic helical 4DCT. Careful selection of parameters (lowering kV and SNR) can help to further reduce the dose.