Mehran Baghi

Quantitative measurements of perfusion and permeability of oropharyngeal and oral cavity cancer, recurrent disease, and associated lymph nodes using first-pass contrast-enhanced computed tomography studies.

Objectives:We sought to evaluate the routine clinical use of perfusion computed tomography in the detection and differentiation of primary and recurrent oropharynx and oral cavity tumors as well as of nodal disease. Materials and Methods:A total of 77 patients with primary cancer as well as suspected recurrent disease and lymph nodes were evaluated. A dynamic acquisition (4 × 6-mm slices) of the largest axial tumor surface was performed and the tumor blood flow (BF), blood volume (BV), and mean transit time (MTT) were calculated by using a modified deconvolution-based analysis taking into account the extravasation of the contrast agent for permeability surface area product imaging (PS). Tumor volume was calculated and region of interest analysis was performed on the pathologic and normal tissue. Results:The mean BF, BV, and PS values in the primary tumors (77.48 mL/min/100 g tissue; 5.29 mL/min; 13.33 mL/min/100 g tissue, respectively) were highly significantly different (P < 0.01) than those obtained in the normal structures. Mean MTT values (9.01 seconds) also were significantly lowered in the tumors compared with normal tissue (P < 0.05). There was no statistical difference in the perfusion values between the primary and the recurrent tumors. Recurrent disease could be differentiated on the basis of BF (P < 0.05) from tissue changes after chemo-radiation-treatment (mean BF: 69.71 versus 45.31 mL/min/100 g tissue, respectively). Differentiation of the lymph nodes was not possible by means of perfusion values. Tumor volume did not significantly correlate with any perfusion parameter. Conclusions:Perfusion CT of oropharyngeal and oral cavity cancer in clinical routine is feasible and helps outlining the malignant tissue as well as differentiating recurrent disease from nonspecific post-therapeutic changes.

Cervical lymph nodes

The lymph node staging is a very important prognostic parameter for patients with presenting with head neck cancer and is influencing the selection of the different therapeutic strategies including surgery, chemotherapy, radiotherapy or a combination of them. The accuracy of imaging techniques, such as US, MR imaging, and CT, depends on the appropriateness of radiological criteria used for diagnosing lymph node metastases. Size of nodes and evidence of necrosis are still the most important radiological criteria. However, the size shows great variability. A spherical lymph node larger than 10mm is an indicator for a malignant node, whereas an oval shape and/or a fatty hilus are more benign signs. But there are many limitations and different cut offs published in the literature, indicating that the size of a lymph node is not a reliable criteria for the assessment of lymph nodes in the head and neck region. Today new high-resolution MRI sequences and the development of specific contrast agents are offering new possibilities in the diagnostic work-up of head and neck lymph nodes. Ultrasmall superparamagnetic iron oxide particles (USPIOs) are resulting after intravenous application in a reduction of the T2 relaxation time. This is causing a signal decrease on T2-weighted MR images in benign lymph nodes after administration of USPIOs, whereas malignant lymph nodes do not show a significant signal decrease. Some clinical studies presented already very promising results. Based on the fact, that the size evaluation of lymph nodes in the head and neck has not changed during the last decade, this paper will mainly focus on MRI with new contrast agents and new techniques as diffusion weighted imaging (DWI).

Dynamic contrast-enhanced CT of head and neck tumors: perfusion measurements using a distributed-parameter tracer kinetic model. Initial results and comparison with deconvolution-based analysis

The objective of this work was to evaluate the feasibility of a two-compartment distributed-parameter (DP) tracer kinetic model to generate functional images of several physiologic parameters from dynamic contrast-enhanced CT data obtained of patients with extracranial head and neck tumors and to compare the DP functional images to those obtained by deconvolution-based DCE-CT data analysis. We performed post-processing of DCE-CT studies, obtained from 15 patients with benign and malignant head and neck cancer. We introduced a DP model of the impulse residue function for a capillary-tissue exchange unit, which accounts for the processes of convective transport and capillary-tissue exchange. The calculated parametric maps represented blood flow (F), intravascular blood volume (v(1)), extravascular extracellular blood volume (v(2)), vascular transit time (t(1)), permeability-surface area product (PS), transfer ratios k(12) and k(21), and the fraction of extracted tracer (E). Based on the same regions of interest (ROI) analysis, we calculated the tumor blood flow (BF), blood volume (BV) and mean transit time (MTT) by using a modified deconvolution-based analysis taking into account the extravasation of the contrast agent for PS imaging. We compared the corresponding values by using Bland-Altman plot analysis. We outlined 73 ROIs including tumor sites, lymph nodes and normal tissue. The Bland-Altman plot analysis revealed that the two methods showed an accepted degree of agreement for blood flow, and, thus, can be used interchangeably for measuring this parameter. Slightly worse agreement was observed between v(1) in the DP model and BV but even here the two tracer kinetic analyses can be used interchangeably. Under consideration of whether both techniques may be used interchangeably was the case of t(1) and MTT, as well as for measurements of the PS values. The application of the proposed DP model is feasible in the clinical routine and it can be used interchangeably for measuring blood flow and vascular volume with the commercially available reference standard of the deconvolution-based approach. The lack of substantial agreement between the measurements of vascular transit time and permeability-surface area product may be attributed to the different tracer kinetic principles employed by both models and the detailed capillary tissue exchange physiological modeling of the DP technique.

Demands on caring relatives of head and neck cancer patients

Background: Relatives of cancer patients experience high levels of stress that influence the quality of life of these individuals. To investigate whether there is a necessity for simultaneous supportive care of patient relatives, we performed for the first time a study asking the closest relatives of head and neck cancer patients about their needs during and after the treatment to consider how to optimize the situation for such patient groups.

Hypofractionated accelerated CT-guided interstitial 192Ir-HDR-Brachytherapy as re-irradiation in inoperable recurrent cervical lymphadenopathy from head and neck cancer

BACKGROUND Despite significant improvements in the treatment of head and neck cancer (HNC), lymph node recurrences remain a clinical challenge after primary radiotherapy. The value of interstitial (IRT) brachytherapy (BRT) for control of lymph node recurrence remains unclear. In order to clarify its role a retrospective review was undertaken on the value of computed tomography (CT)-guided IRT high-dose-rate (HDR)-BRT in isolated recurrent disease from HNC. PATIENTS AND METHODS From 2000 to 2007, 74 patients were treated for inoperable recurrent cervical lymphadenopathy. All patients had previously been treated with radical radiotherapy or chemoradiation with or without surgery. The HDR-BRT delivered a median salvage dose of 30.0 Gy (range, 12.0-36.0 Gy) in twice-daily fractions of 2.0-5.0 Gy in 71 patients and of 30.0 Gy (range, 10.0-36.0 Gy) in once-daily fractions of 6.0-10.0 Gy in three patients. RESULTS The overall and disease-free survival rates at one, two and three years were 42%, 19%, 6%, and 42%, 37% and 19%, respectively. The local control probability at one, two and three years was 67% at all three time points. Grade III-IV complications occurred in 13% of patients. CONCLUSIONS In patients with inoperable recurrent neck disease from HNC, hypofractionated accelerated CT-guided IRT-HDR-BRT can play an important role in providing palliation and tumor control.

Variance of Angular Insertion Depths in Free-Fitting and Perimodiolar Cochlear Implant Electrodes

Objective: To assess the variance in cochlear implant electrode insertion depth in degrees around the modiolus (angular insertion depth) in free-fitting and perimodiolar electrode arrays. Materials and Methods: Twenty-eight fresh human temporal bones were implanted with free-fitting cochlear implant electrodes, and 18 bones were implanted using perimodiolar electrode arrays. Specimens were embedded, and 2-dimensional radiographs were obtained to assess angular insertion depths. Histologic serial sections of undecalcified bones were then evaluated to analyze intracochlear electrode positions. Finally, linear surgical insertion depths (in millimeters) were correlated with angular insertion depth (degrees around the modiolus). Results: A moderate variance of angular insertion depth was documented for both free-fitting and perimodiolar electrode arrays. Full insertions into the scala tympani ranged from 540 to 630 degrees with free-fitting arrays and from 270 to 375 degrees with perimodiolar electrodes. In free-fitting devices, a linear relationship between linear (in millimeters) and angular (degrees) insertion depths was observed. Insertions into scala vestibuli were observed in 9 of 28 and 5 of 18 of the specimens for free-fitting and perimodiolar electrodes, respectively. Additionally, scala vestibuli insertions showed greater angular insertion depths when compared with scala tympani implantations. Conclusion: Variances in angular insertion depths seem to be moderate and similar in free-fitting and perimodiolar electrode arrays. Scala vestibuli insertions showed greater angular insertion depths than comparable insertions into the scala tympani. In perimodiolar electrodes, angular insertion depths equal or greater than 390 degrees suggested scala vestibuli placement.

Usefulness of MRI volumetric evaluation in patients with squamous cell cancer of the head and neck treated with neoadjuvant chemotherapy

The purpose was to evaluate the efficacy of tumor volumetry on MRI as predictive of response to treatment with induction chemotherapy, comparing the results with endoscopy.

Inverse correlation between serum PGE2 and T classification in head and neck cancer

Prostaglandin E2 (PGE2) serum levels have been shown previously to be increased in tumor bearing mice as well as in patients with solid tumors; however, the impact on the course or stage of disease has not been shown. We hypothesized that PGE2 is strictly required for aggressive and especially early‐stage tumors of the head and neck to provoke invasion and angiogenesis.

Dynamic contrast-enhanced CT of head and neck tumors: comparison of first-pass and permeability perfusion measurements using two different commercially available tracer kinetics models.

RATIONALE AND OBJECTIVES To evaluate the interchangeability of perfusion parameters between two software packages for the postprocessing of dynamic contrast-enhanced (DCE) computed tomographic images of head and neck tumors. MATERIALS AND METHODS DCE computed tomographic images of 75 patients with head and neck tumors were postprocessed using a software package based on the maximum-slope approach and Patlak analysis, as well as a software package with deconvolution-based analysis incorporating an adiabatic approximation of tissue homogeneity (ATH) model. The evaluated perfusion parameters included blood flow (F), blood volume (v), and permeability-surface area product (PS). Region-of-interest (ROI) analysis of the tumors and the metastatic lymph nodes was performed. The perfusion parameters were compared using the Wilcoxon matched-pairs test and Bland-Altman plots. RESULTS One hundred fifty-two ROIs of tumors and nodes were outlined and analyzed. Moderate to good correlations were demonstrated between the various perfusion values (r = 0.56-0.72, P < .0001). The Wilcoxon test revealed a significant difference between the two methods (P < .001), with the F, v, and PS values obtained using the maximum-slope approach and Patlak analysis higher than those obtained using deconvolution-based analysis with the assumptions of the ATH model. The Bland-Altman plots for F and v values revealed a proportionality trend with outliers, which were strongly associated with the magnitudes of the parameters. Analysis of the PS values did not show any systematic bias. CONCLUSION There were significant differences in the perfusion parameters obtained using the two software packages, and thus, these parameters are not directly interchangeable.

Gadolinium-enhanced echo-planar T2-weighted MRI of tumors in the extracranial head and neck: Feasibility study and preliminary results using a distributed-parameter tracer kinetic analysis

To examine the feasibility of first‐pass dynamic contrast‐enhanced (DCE) T2‐weighted MRI of tumors in the extracranial head and neck by applying a distributed‐parameter (DP) tracer kinetic model to quantify the perfusion parameters.