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R Hermans

Publications and source records attributed to R Hermans.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of the larynx for tumour recurrence by diffusion-weighted MRI after radiotherapy: initial experience in four cases.

Radiotherapy-induced changes in the soft tissues of the neck hamper the early detection of persistent or recurrent tumour by clinical examination and imaging procedures. Diffusion-weighted (DW) MRI is a non-invasive technique capable of probing tissue properties by measuring the movement of water. The purpose of the ongoing study is to examine the usefulness of DW-MRI for differentiation of persistent or recurrent tumour from post-radiotherapeutic sequelae or complications. Four patients, suspected of tumour recurrence after radiotherapy for laryngeal squamous cell carcinoma, were examined using a DW-MRI sequence on a clinical 1.5 T MR system prior to surgery. In two patients, the DW-MRI images showed an asymmetric hyperintense lesion on b1000 images with low apparent diffusion coefficient (ADC)-value, compatible with tumour on histopathology. All surrounding tissue presented high ADC values and absent signal on the b1000 images, histopathologically correlating to post-radiotherapeutic changes. The images of the third and fourth patient showed absent or minimal symmetric hyperintensity of the laryngeal soft tissues on the b1000 images and high ADC-values. In these cases, the histopathological diagnosis of radionecrosis was made and no tumour was found. In all four cases, differentiation of tumoral tissue from radiotherapy-induced tissue alterations was possible with DW-MRI.

Aged↗
PubMed2005

Chronic maxillary atelectasis.

Chronic maxillary atelectasis (CMA) is characterized by a reduced maxillary sinus volume due to an inward bowing of one or more of the sinus walls. The disorder is probably caused by an obstruction of the maxillary ostium, leading to a persistent negative pressure within the sinus lumen. To provide insight into the epidemiology, pathogenesis and treatment of this disorder, a retrospective study of twelve cases that met radiographic criteria of CMA was carried out. The patients were equally divided between both sexes and were on average 25 years old. Five of the twelve patients were under eighteen years of age. The patients had chronic sinonasal complaints except two, who had a "silent sinus syndrome", characterized by enophthalmos associated with a marked sinus deformation. This is the first report of CMA associated with a benign nasal tumour and also of CMA following cicatrisation due to nasal packing for bleeding after endoscopic sinus surgery. All patients were treated surgically by creating a middle meatal antrostomy, thus restoring sinus ventilation. To conclude, CMA is rare and probably underestimated, especially in the paediatric population. Different entities causing a complete ostial occlusion can lead to CMA. Endoscopically restoring maxillary sinus ventilation is the recommended treatment.

Adult↗
PubMed2004

Boron biodistribution in beagles after intravenous infusion of 4-dihydroxyborylphenylalanine-fructose complex.

Boron biodistribution after intravenous infusion of 4-dihydroxyborylphenylalanine-fructose (BPA-F) complex was investigated in six dogs. Blood samples were evaluated during and following doses of 205 and 250 mg/kgbw BPA in a 30 min infusion, and 500 mg/kgbw in a 1h infusion. Samples from whole blood, urine, brain and other organs were analysed for boron content after varying times following the onset of infusion. The whole blood boron concentrations declined from 27 to 8.4 ppm over the period of 39-165 min after the onset of infusion and the levels increased from 1.9 to 12 ppm in the grey matter of the brain over the same period. The boron concentrations in whole blood decreased steadily, whereas the boron values in brain tissue rose steadily with time. It was concluded that whole blood boron concentrations do not seem to reflect accurately the boron concentration in brain tissue at respective time points.

Animals↗
PubMed2003

Development of the orohypopharyngeal cavity in normal infants and young children.

OBJECTIVE: To study the growth of the oropharynx and hypopharynx in infants and young children by measuring the lengths of the segments between nasopharyngeal valve and tongue base, tongue base and arytenoids, and arytenoids and upper esophageal sphincter. These measurements will be used as references for developing manofluoroscopy to study deglutition in infants and young children. PATIENTS AND METHODS: Twenty-three children (14 boys, 9 girls) between birth and 4 years of age were prospectively studied. All children had near normal growth parameters and were free of medical illnesses or other major medical conditions that are known to influence the pharyngeal cavity. Lateral videofluoroscopy was used to assess the pharyngeal structures during breathing. All images were digitally recorded and analyzed using a computer program designed specifically for this study. RESULTS AND CONCLUSIONS: Statistically significant correlations were found between the age or height of the patient and the distance from velopharyngeal valve to tongue base and the distance from tongue base to arytenoids, showing a linear increase of the length of the oro- and hypopharynx with age and patient height. There was no significant difference in the pharyngeal distances between boys and girls. On the basis of these results, a linear regression comparison could be established to define the length of each pharyngeal segment for any age until 4 years and for the 50th percentile of height.

Age Factors↗
PubMed2001

Lymph node metastases from head and neck squamous cell carcinoma: MR imaging with ultrasmall superparamagnetic iron oxide particles (Sinerem MR) -- results of a phase-III multicenter clinical trial.

The aim of this study was to compare the clinical usefulness of ultrasmall superparamagnetic iron oxide (USPIO) MR contrast media (Sinerem, Guerbet Laboratories, Aulnay-sous-Bois, France) with precontrast MRI in the diagnosis of metastatic lymph nodes in patients with head and neck squamous cell carcinoma, using histology as gold standard. Eighty-one previously untreated patients were enrolled in a multicenter phase-III clinical trial. All patients had a noncontrast MR, a Sinerem MR, and surgery within a period of 15 days. The MR exams were analyzed both on site and by two independent radiologists (centralized readers). Correlation between histology and imaging was done per lymph node groups, and per individual lymph nodes when the short axis was > or = 10 mm. For individual lymph nodes, Sinerem MR showed a high sensitivity (> or = 88%) and specificity (> or = 77%). For lymph node groups, the sensitivity was > or = 59% and specificity > or = 81%. False-positive results were partially due to inflammatory nodes; false-negative results from the presence of undetected micrometastases. Errors of interpretation were also related to motion and/or susceptibility artifacts and problems of zone assignment. Sinerem MR had a negative predictive value (NPV) > or = 90% and a positive predictive value (PPV) > or = 51%. The specificity and PPV of Sinerem MR were better than those of precontrast MR. Precontrast MR showed an unexpectedly high sensitivity and NPV which were not increased with Sinerem MR. The potential contribution of Sinerem MR still remains limited by technical problems regarding motion and susceptibility artifacts and spatial resolution. It is also noteworthy that logistical problems, which could reduce the practical value of Sinerem MR, will be minimized in the future since Sinerem MR alone performed as good as the combination of precontrast and Sinerem MR.

Adult↗
PubMed2001

Laryngeal squamous cell carcinoma presenting as a prelaryngeal neck abscess: report of two cases.

Head and neck tumours presenting as a neck abscess are extremely rare. Two patients with laryngeal squamous cell carcinoma, presenting with a prelaryngeal abscess, are described. Although clinically and on the CT studies these cases were suspect for underlying malignancy, the initial biopsies were negative for cancer. Because of persistent suspicion, repeat biopsies finally confirmed the presence of a squamous cell carcinoma. Pathological examination after total laryngectomy showed cancer localised in one of the true vocal cords, invading the anterior commissure and thyroid cartilage. However, the prelaryngeal soft tissues were free of tumour, showing only inflammatory changes and collections of pus. These cases emphasize the importance of repeat targeted biopsies and follow-up CT-studies in patients with a prelaryngeal abscess of obscure aetiology, in order to exclude or confirm a possible underlying malignancy.

Airway Obstruction↗
PubMed2001

The relation of CT-determined tumor parameters and local and regional outcome of tonsillar cancer after definitive radiation treatment.

PURPOSE: To investigate the value of CT-derived tumor parameters as predictor of local and regional outcome of tonsillar squamous cell carcinoma treated by definitive radiation therapy. METHODS AND MATERIALS: The pretreatment CT studies of 112 patients with tonsillar squamous cell carcinoma were reviewed. After redigitizing the films, primary and nodal tumor volume was calculated with the summation-of-areas technique. The nodal CT aspect was graded using a 3-point scale (homogenous, inhomogeneous, and necrotic). Mean follow-up time was 33 months. Actuarial statistical analysis of local and regional outcome was done for each of the covariates; multivariate analysis was performed using Cox's proportional hazards model. RESULTS: In the actuarial analysis, CT-determined primary tumor volume was significantly correlated with local recurrence rate (p < 0.05) when all patients were considered, but primary tumor volume did not predict local control within the T2, T3, and T4 category. CT-determined nodal volume was significantly related to regional outcome (p < 0.01), but nodal density was not. Total tumor volume was not significantly related to locoregional outcome (p = 0.1). In the multivariate analysis, the T and N categories were the independent predictors of local and regional outcomes, respectively. CONCLUSION: Compared to other head-and-neck sites, primary and nodal tumor volume have only marginal predictive value regarding local and regional outcome after radiation therapy in tonsillar cancer.

Adult↗
PubMed2001

Sinochoanal polyp and its variant, the angiomatous polyp: MRI findings.

The angiomatous polyp corresponds to the vascular compromised nasochoanal part of a sinochoanal polyp. We describe the MRI characteristics of such lesions in four patients. All patients had an angiomatous polyp, in three cases as part of an antrochoanal polyp, and in one case as part of a sphenochoanal polyp. The unenhanced MR images depicted the typical appearance of a sinochoanal polyp, hypointense on T1-weighted and hyperintense on T2-weighted images. On gadolinium-enhanced MR images, the sinusal part showed little or no peripheral enhancement; however, the nasochoanal part, corresponding to the angiomatous polyp, showed strong enhancement. An angiomatous polyp mimics a hypervascular mass lesion on enhanced MR studies. The anatomic location and association with a sinusal polyp allows the correct diagnosis.

Adolescent↗
PubMed2001

BOLD contrast fMRI of whole rodent tumour during air or carbogen breathing using echo-planar imaging at 1.5 T.

The aim of this study was to evaluate the feasibility of functional MR imaging (fMRI) at 1.5 T, exploiting blood oxygenation level-dependent (BOLD) contrast, for detecting changes in whole-tumour oxygenation induced by carbogen (5% CO2+95% O2) inhalation of the host. Adult WAG/Rij rats with rhabdomyosarcomas growing subcutaneously in the lower flank were imaged when tumours reached sizes between 1 and 11 cm3 (n=12). Air and carbogen were alternatively supplied at 2 l/min using a snout mask. Imaging was done on a 1.5-T MR scanner using a T2*-weighted gradient-echo, echo-planar imaging (GE-EPI) sequence. Analysis of the whole-tumour EPI images was based on statistical parametric maps. Voxels with and without signal intensity changes (SIC) were recorded. Significance thresholds were set at p<0.05, corrected for multiple comparisons. In continuous air breathing condition, 3 of 12 tumours showed significant negative SIC and 1 tumour had a clear-cut positive SIC. The remaining tumours showed very little or no change. When switching to carbogen breathing, the SIC were significantly positive in 10 of 12 tumours. Negative SIC were present in 4 tumours, of which three were simultaneously characterised by positive SIC. The overall analysis indicated that 6 of the 12 tumours could be considered as strong positive responders to carbogen. Our research demonstrates the applicability of fMRI GE-EPI at 1.5 T to study whole-tumour oxygenation non-invasively. The observed negative SIC during air condition may reflect the presence of transient hypoxia during these measurements. Selection of tumours on the basis of their individual response to carbogen is possible, indicating a role of such non-invasive measurements for using tailor-made treatments.

Animals↗
PubMed2001

Absorbed doses from spiral CT and conventional spiral tomography: a phantom vs. cadaver study.

For several radiological examinations, a clinician can select between conventional and spiral computed tomography. Using both techniques, this study aimed at evaluating the difference in absorbed doses when examining a single lateral jaw segment in a human cadaver head and Rando phantom. The present study involved the placement of thermoluminescent dosimeter (TLD) chips (GR-200) in the thyroid gland, and bilaterally, in the parotid and submandibular glands and the lenses of the eyes in both a human cadaver and a Rando phantom at corresponding locations. Consecutive conventional spiral tomographic examinations were carried out in both the left upper and lower premolar area, using a Cranex TOME multifunctional unit. Each examination consisted of 4 slices with a 2 mm slice thickness and exposure parameters of 57 kV, 56 seconds and 1.6-2.0 mA. Regarding spiral computed tomography (CT), a Somatom Plus S scanner (Siemens, Erlangen, Germany), with a slice thickness of 1 mm with settings at 120 kV and 165 mA, was used on both phantoms and separately in the upper and lower jaw. With conventional tomography, the findings of the present study showed that the parotid and submandibular glands on the side near the X-ray tube received the highest dose, both for the cadaver head (doses ranging from 0.5 to 1.3 mGy) and the phantom (doses ranging from 0.6 to 2.6 mGy). For CT of the upper jaw, the highest doses were delivered to the parotid glands with an average absorbed dose of 9.2 and 10.6 mGy for the cadaver head and phantom, respectively. The submandibular glands received the highest doses during CT examination of the lower jaw with an average of 7.8 and 12.9 mGy for the cadaver head and phantom, respectively. It appears from the present investigation that if small edentulous regions are examined, radiation doses during conventional tomography remain much lower than during CT imaging. However, when multiple tomographic cuts are required, a spiral CT examination can replace a series of conventional examinations, especially in cases such as the rehabilitation of an edentulous upper jaw or a more complex surgery.

Aged↗
PubMed2001

The utility of SPECT in determining the relationship between radiation dose and salivary gland dysfunction after radiotherapy.

Salivary gland scintigraphy (SGS) is used to depict salivary gland dysfunction after radiotherapy (RT). The aim of this study was to investigate the utility of SGS combined with single photon emission computed tomography (SPECT). Twenty-one patients with a carcinoma of head and neck underwent SGS before and 1 month after RT. After injection of 370 MBq 99Tcm-pertechnetate, a biplanar dynamic acquisition (12 x 1 min) was started, followed by a SPECT acquisition during 4 min. Carbachol was then injected and a second dynamic study (16 x 1 min) was performed, again followed by a SPECT acquisition. The salivary excretion fraction (SEF) was calculated both from the geometric mean planar image for each parotid and from the SPECT data for each transverse plane through the parotids. The RT-induced changes in the SEF (dSEF) were correlated with the mean radiation dose calculated using tomography-based dosimetry. The mean radiation dose to the parotids was 44 Gy (range 4.4-68.1 Gy). The mean range of the variation in radiation dose to the transverse slices within the parotids of a patient was 24 Gy (range 6.2-51.9 Gy). Considering all transverse planes through the parotids in all patients, a linear correlation was found between the dSEF calculated using SGS-SPECT and the radiation dose (r=0.45, P=0.0001). Thirteen patients had a variation in radiation dose within the parotids of more than 20 Gy. In nine of these a significant intra-individual correlation between radiation dose and the dSEF of the transverse parotid slices was found (r range 0.55-0.97; P value range 0.037-0.0001). In conclusion, SGS-SPECT can be used for monitoring radiation-induced parotid gland dysfunction. It offers the unique possibility for the assessment of intra-individual dose-dysfunction curves in patients with large variations in the radiation dose within the parotids.

Adult↗
PubMed2001

Prefabrication of composite tissue for improved tracheal reconstruction.

Tracheal repair tissues were evaluated experimentally to provide an evidence-based choice for decision-making in clinical tracheal reconstruction. Tracheal reconstructive tissue was characterized as providing for vascularization, support, and/or lining. A tissue equivalent was developed in the rabbit for each of the individual tissues. The individual tissues consisted of nonepithelialized soft tissue (vascularized fascia), epithelialized tissue (vascularized fascia grafted with buccal mucosa), and supportive tissue (ear cartilage). The 3 reconstructive tissues were evaluated in 30 rabbits after repair of an anterior laryngotracheal defect. Morphometric and histologic analysis was applied to the reconstructions. After a 1-month follow-up period, defects repaired with nonepithelialized soft tissue showed healing by secondary intention and a wound that was contracted to 44% of the initial surface area of the defect. Mucosa-lined soft tissue flaps and cartilage grafts showed a less than 10% wound contraction. Compared to cartilage grafts, mucosalined soft tissue (vascularized fascia grafted with buccal mucosa) seemed preferable for clinical use, because it showed healing by primary intention. A mucosa-lined radial forearm fascia flap was used successfully in cases of restenosis after tracheal resection. One deficiency of the mucosa-lined soft tissue was the absence of supportive tissue. In cases of extensive stenosis, it might be useful to obtain additional expansion of the airway lumen by creating a convexity at the site of reconstruction. In a second set of experiments, we attempted to improve the mucosa-lined soft tissue concept by adding elastic cartilage. A composite tissue consisting of vascularized fascia, buccal mucosa, and auricular cartilage was developed. Heterotopic prefabrication of the composite tissue was essential for survival of the cartilaginous component. Additional airway lumen expansion could be obtained after heterotopic flap prefabrication. After experimental evaluation, the concept of the prefabricated composite tissue was successfully applied in a clinical case of long-segment stenosis. Experimental and clinical evidence suggests that the combination of buccal mucosa and fascia form an optimized tissue combination for tracheal reconstruction. This combination can be improved by adding strips of autologous ear cartilage.

Adolescent↗
PubMed2000

Results of larynx preservation surgery for advanced laryngeal cancer through tracheal autotransplantation.

OBJECTIVE: To evaluate the use of tracheal autotransplantation for reconstruction of the hemilaryngectomy defect that includes the hemicricoid cartilage and results from resection of laryngeal or hypopharyngeal cancer. DESIGN: The clinical records of 28 patients undergoing primary or salvage hemicrico-hemilaryngectomy for laryngeal (26 patients) and pyriform sinus (2 patients) cancer were analyzed for function and local control. SETTING: Academic center. PATIENTS: Case series review of 28 consecutive patients treated during a 3(1/2)-year period who had an average follow-up period of 19 months. INTERVENTION: Twenty-five men and 3 women, aged from 28 to 79 years, underwent a hemilaryngectomy that included the hemicricoid cartilage, the ipsilateral thyroid lobe, and a unilateral or bilateral lymph node dissection. In 26 patients, these extensive defects were reconstructed with a tracheal autotransplantation that restored the larynx at the glottic and subglottic levels. In 2 patients, the defect was converted into a total laryngectomy because of tumor extension beyond the resection margins of a hemicrico-hemilaryngectomy. MAIN OUTCOME MEASURES: The times to decannulation and retake of full oral feeding, the quality of speech, and the incidence and site of recurrent cancer were assessed. RESULTS: Of the 26 patients undergoing tracheal autotransplantation, 24 were decannulated and all regained the ability to maintain nutrition by mouth. Ultimate voice quality was "subnormal" to "moderately hoarse" in all patients. Five recurrences developed of which 2 were treated with total laryngectomy. CONCLUSIONS: Functional reconstruction of extensive laryngeal defects can be achieved with an autotransplantation of cervical trachea, with favorable functional results and acceptable morbidity. This technique expands the limits of conservation surgery for selected laryngeal and hypopharyngeal tumors.

Adult↗
PubMed2000

The accuracy of spiral tomography to assess bone quantity for the preoperative planning of implants in the posterior maxilla.

When planning to place implants in the posterior region of the maxilla, the location of the maxillary sinus floor is influencing the available bone height and the implant length chosen. The aim of the present study was to evaluate in vitro the spiral tomographic technique that could be used for pre-operative implant planning. Tomographs were taken of 6 dry human skulls using the Cranex Tome multifunctional unit (Orion Corporation Soredex, Helsinki, Finland). Three sites were selected in the left posterior maxilla and marked with gutta percha meaning a total of 18 sites (6 x 3 = 18) for interpretation. Bone height and width were measured on the tomographs and after sectioning also on the skulls. The values obtained from the measurements on tomographs were divided by an enlargement factor of 1.5 (as defined by the manufacturer) and then compared with those from the real measurements on the skulls. Real measurements were on average 0.24 mm (SD 0.19) lower than the tomographic measurements (P < 0.05). From the present results it could be concluded that spiral tomography using the recently developed Cranex Tome reveals sufficient information and detail for pre-operative planning of a limited edentulous region.

Adult↗
PubMed2000

Laryngeal or hypopharyngeal squamous cell carcinoma: can follow-up CT after definitive radiation therapy be used to detect local failure earlier than clinical examination alone?

PURPOSE: To determine if follow-up computed tomography (CT) after definitive radiation therapy for laryngeal or hypopharyngeal (laryngopharyngeal) carcinoma allows the detection of local failure earlier than clinical examination alone. MATERIALS AND METHODS: Pre- and post-radiation therapy follow-up CT scans in 66 patients were reviewed retrospectively. All patients underwent definitive hyperfractionated radiation therapy and were followed up clinically for at least 2 years after its completion. Post-radiation therapy CT scans (N = 153) were evaluated for posttreatment changes with a three-point score: A score of 1 represented expected posttreatment changes; 2, focal mass with a maximal diameter of less than 1 cm and/or asymmetric obliteration of laryngeal tissue planes; or 3, focal mass with a maximal diameter equal to or greater than 1 cm or estimated tumor volume reduction of less than 50%. All patients underwent the first posttreatment CT study 1-6 months after therapy. New or progressive laryngeal cartilage changes were noted. The clinical impression of the larynx at the time of each follow-up CT scan was also recorded. RESULTS: In 12 of 29 (41%) patients with treatment failure at the primary site, follow-up CT scans were definite for local failure (score, 3) a mean of 5.5 months (median, 3.5 months; range, 1-17 months) before clinical examination results. CONCLUSION: In many patients, follow-up CT shows local failure earlier than does clinical examination alone.

Adult↗
PubMed1999

Pre- and post-radiotherapy computed tomography in laryngeal cancer: imaging-based prediction of local failure.

PURPOSE: To determine if pre-radiotherapy (RT) and/or post-radiotherapy computed tomography (CT) can predict local failure in patients with laryngeal carcinoma treated with definitive RT. METHODS AND MATERIALS: The pre- and post-RT CT examinations of 59 patients (T3 glottic carcinoma [n = 30] and T1-T4 supraglottic carcinoma [n = 29]) were reviewed. For each patient, the first post-RT CT study between 1 and 6 months after irradiation was used. All patients were treated with definitive hyperfractionated twice-daily continuous-course irradiation to a total dose of 6,720-7,920 cGy, and followed-up clinically for at least 2 years after completion of RT. Local control was defined as absence of primary tumor recurrence and a functioning larynx. On the pre-treatment CT study, each tumor was assigned a high-or low-risk profile for local failure after RT. The post-RT CT examinations were evaluated for post-treatment changes using a three-point post-RT CT-score: 1 = expected post-RT changes; 2 = focal mass with a maximal diameter of < 1 cm and/or asymmetric obliteration of laryngeal tissue planes; 3 = focal mass with a maximal diameter of > 1 cm, or < 50% estimated tumor volume reduction. RESULTS: The local control rates at 2 years post-RT based on pre-treatment CT evaluation were 88% for low pre-treatment risk profile patients (95% CI: 66-96%) and 34% (95% CI: 19-50%) for high pre-treatment risk profile patients (risk ratio 6.583; 95% CI: 2.265-9.129;p = 0.0001). Based on post-treatment CT, the local control rates at 2 years post-RT were 94% for score 1, 67% for score 2, and 10% for score 3 (risk ratio 4.760; 95% CI: 2.278-9.950 p = 0.0001). Post-RT CT scores added significant information to the pre-treatment risk profiles on prognosis. CONCLUSIONS: Pre-treatment CT risk profiles, as well as post-RT CT evaluation can identify patients, irradiated for laryngeal carcinomas, at high risk for developing local failure. When the post-RT CT score is available, it proves to be an even better prognosticator than the pre-treatment CT-risk profile.

Carcinoma, Squamous Cell↗