Internal cerebral vein asymmetry on follow-up brain computed tomography after intravenous thrombolysis in acute anterior circulation ischemic stroke is associated with poor outcome.

BACKGROUND: Identifying early predictors of functional outcome after acute ischemic stroke (AIS) is important for planning rehabilitation strategies. Internal cerebral veins (ICV) drain deep parts of brain, run parallel to each other, and consistently seen on computed tomography angiography (CTA). Even minor asymmetry in their filling can be identified. We hypothesized that venous drainage would be impaired in patients with acute occlusion of internal carotid artery or middle cerebral artery. Because systemic thrombolysis can alter the vascular findings, we evaluated the relationship between ICV asymmetry on follow-up CTA and functional outcome. METHODS: Consecutive AIS patients treated with intravenous thrombolysis between 2007 and 2010 were included. ICV asymmetry was assessed by 2 independent blinded stroke neurologists/neuroradiologists. Functional outcome was assessed by the modified Rankin Scale (mRS) at 3 months, dichotomized as good (0-1) and poor (2-6). Data were analyzed for predictors of functional outcome. RESULTS: Of 2238 patients with AIS, 226 (10.1%) anterior circulation AIS patients received intravenous thrombolysis. The median age was 65 years (range 19-92), 44% were men, and median National Institutes of Health Stroke Scale (NIHSS) score was 16 points (range 4-32). Hypertension was the commonest risk factor in 173 (76.5%) patients, whereas 78 (34.5%) had atrial fibrillation. ICV asymmetry on follow-up CTA was assessed in 103 (45.5%) patients. Admission NIHSS score (odds ratio [OR] 1.07; 95% confidence interval [CI] 1.079-1.201, P = .046), change in NIHSS score during first 24 hours (OR .737; 95% CI .672-.807, P < .0001), and ICV asymmetry on follow-up CTA (OR 20.3; 95% CI 4.67-52.07, P < .0001) independently predicted poor outcome at 3 months. CONCLUSIONS: ICV asymmetry on follow-up CTA after intravenous thrombolysis is an early predictor of poor functional outcome.

Early and continuous neurologic improvements after intravenous thrombolysis are strong predictors of favorable long-term outcomes in acute ischemic stroke.

BACKGROUND: Intravenously administered tissue plasminogen activator (IV tPA) remains the only approved therapeutic agent for arterial recanalization in acute ischemic stroke (AIS). Considerable proportion of AIS patients demonstrate changes in their neurologic status within the first 24 hours of intravenous thrombolysis with IV tPA. However, there are little available data on the course of clinical recovery in subacute 2- to 24-hour window and its impact. We evaluated whether neurologic improvement at 2 and 24 hours after IV tPA bolus can predict functional outcomes in AIS patients at 3 months. METHODS: Data for consecutive AIS patients treated with IV tPA within 4.5 hours of symptom onset during 2007-2011 were prospectively entered in our thrombolyzed registry. National Institutes of Health Stroke Scale (NIHSS) scores were recorded before IV tPA bolus, at 2 and 24 hours. Early neurologic improvement (ENI) at 2 hours was defined as a reduction in NIHSS score by 10 or more points from baseline or an absolute score of 4 or less points at 2 hours. Continuous neurologic improvement (CNI) was defined as a reduction of NIHSS score by 8 or more points between 2 and 24 hours or an absolute score of 4 or less points at 24 hours. Favorable functional outcomes at 3 months were determined by modified Rankin Scale (mRS) score of 0-1. RESULTS: Of 2460 AIS patients admitted during the study period, 263 (10.7%) received IV tPA within the time window; median age was 64 years (range 19-92), with 63.9% being men, a median NIHSS score of 17 points (range 5-35), and a median onset-to-treatment time of 145 minutes (range 57-270). Overall, 130 (49.4%) thrombolyzed patients achieved an mRS score of 0-1 at 3 months. The female gender, age, and baseline NIHSS score were found to be significantly associated with CNI on univariate analysis. On multivariate analysis, NIHSS score at onset and female gender (odds ratio [OR]: 2.218, 95% confidence interval [CI]: 1.140-4.285; P=.024) were found to be independent predictors of CNI. Factors associated with favorable outcomes at 3 months on univariate analysis were younger age, female gender, hypertension, NIHSS score at onset, recanalization on transcranial Doppler (TCD) monitoring or repeat computed tomography (CT) angiography, ENI at 2 hours, and CNI. On multivariate analysis, NIHSS score at onset (OR per 1-point increase: .835, 95% CI: .751-.929, P<.001), 2-hour TCD recanalization (OR: 3.048, 95% CI: 1.537-6.046; P=.001), 24-hour CT angiographic recanalization (OR: 4.329, 95% CI: 2.382-9.974; P=.001), ENI at 2 hours (OR: 2.536, 95% CI: 1.321-5.102; P=.004), and CNI (OR: 7.253, 95% CI: 3.682-15.115; P<.001) were independent predictors of favorable outcomes at 3 months. CONCLUSIONS: Women are twice as likely to have CNI from the 2- to 24-hour period after IV tPA. ENI and CNI within the first 24 hours are strong predictors of favorable functional outcomes in thrombolyzed AIS patients.

Persistence of hyperdense middle cerebral artery sign on follow-up CT scan after intravenous thrombolysis is associated with poor outcome.

BACKGROUND: The rates and extent of recovery in acute ischemic stroke (AIS) patients treated with intravenous tissue plasminogen activator (IV-tPA) remain highly variable. Hyperdense middle cerebral artery sign (HMCAS) on pretreatment unenhanced computerized tomography (CT) of the brain represents the presence of thrombus, often associated with severe neurological deficits and poor clinical outcome at 3 months. However, HMCAS is reliable only in AIS patients managed conservatively. In patients treated with systemic thrombolysis, HMCAS may disappear (representing clot dissolution) or persist (persisting clot) on the follow-up CT scan of the brain. We aimed at evaluating whether disappearance or the persistence of HMCAS on follow-up CT scan of the brain can predict the final outcome at 3 months. METHODS: Data from consecutive AIS patients treated with IV-tPA, in a standardized protocol, from January 2007 to March 2010 were included in the prospective thrombolysis registry at our tertiary care center. For this evaluation, posterior circulation stroke was excluded. HMCAS was assessed on admission as well as follow-up CT by 2 independent stroke neurologists, blinded to the patient data or outcomes. Functional outcomes assessed by the modified Rankin Scale (mRS) at 3 months were dichotomized as good (mRS score 0-1) and poor (mRS score 2-6). The data were analyzed for the early predictors of poor functional outcome with SPSS version 19 for Windows. RESULTS: Of the total of 2,238 patients admitted during the study period, 226 (11%) with anterior circulation AIS treated with intravenous thrombolysis were included. Median age of the patients was 65 years (range 19-92), 63% were males and they had a median National Institutes of Health Stroke Scale (NIHSS) score of 16 points (range 4-32). HMCAS was observed on admission CT scan in 109 (48.2%) patients and persisted on follow-up CT in 52 (47.7%) of them. Overall, 108 (47.8%) patients achieved poor functional outcome at 3 months. Admission NIHSS score (OR per 1-point increase = 1.241; 95% CI = 1.151-1.337, p < 0.0005), lesser change in NIHSS score at 24 h (OR per 1-point reduction = 0.730; 95% CI = 0.666-0.800, p < 0.0005) and persistence of HMCAS on follow-up CT scan (OR = 3.352; 95% CI = 1.991-11.333, p = 0.039) were associated with poor outcome at 3 months. CONCLUSION: Persistence of HMCAS on the follow-up CT scan of the brain in acute ischemic stroke patients treated with IV-tPA can be used as an early predictor of poor functional outcome.

CT-based radiomics features in the prediction of thyroid cartilage invasion from laryngeal and hypopharyngeal squamous cell carcinoma.

BACKGROUND: Laryngeal and hypopharyngeal squamous cell carcinoma (LHSCC) with thyroid cartilage invasion are considered T4 and need total laryngectomy. However, the accuracy of preoperative diagnosis of thyroid cartilage invasion remains lower. Therefore, the purpose of this study was to assess the potential of computed tomography (CT)-based radiomics features in the prediction of thyroid cartilage invasion from LHSCC. METHODS: A total of 265 patients with pathologically proven LHSCC were enrolled in this retrospective study (86 with thyroid cartilage invasion and 179 without invasion). Two head and neck radiologists evaluated the thyroid cartilage invasion on CT images. Radiomics features were extracted from venous phase contrast-enhanced CT images. The least absolute shrinkage and selection operator (LASSO) and logistic regression (LR) method were used for dimension reduction and model construction. In addition, the support vector machine-based synthetic minority oversampling (SVMSMOTE) algorithm was adopted to balance the dataset and a new LR-SVMSMOTE model was constructed. The performance of the radiologist and the two models were evaluated with receiver operating characteristic (ROC) curves and compared using the DeLong test. RESULTS: The areas under the ROC curves (AUCs) in the prediction of thyroid cartilage invasion from LHSCC for the LR-SVMSMOTE model, LR model, and radiologist were 0.905 [95% confidence interval (CI): 0.863 to 0.937)], 0.876 (95%CI: 0.830 to 0.913), and 0.721 (95%CI: 0.663-0.774), respectively. The AUCs of both models were higher than that of the radiologist assessment (all P < 0.001). There was no significant difference in predictive performance between the LR-SVMSMOTE and LR models (P = 0.05). CONCLUSIONS: Models based on CT radiomic features can improve the accuracy of predicting thyroid cartilage invasion from LHSCC and provide a new potentially noninvasive method for preoperative prediction of thyroid cartilage invasion from LHSCC.

Significance of tumour volume measurements in tongue cancer: a novel role in staging.

BACKGROUND: Tongue cancers are staged by the American Joint Committee on Cancer and the Union Internationale Contre le Cancer TNM staging systems. Cancer, however, evolves in a 3-D plane. Hence, using the largest tumour diameter will not reflect total cancer volume. We aim to evaluate the use of tongue cancer tumour volume (Tv) as a prognostic predictor of disease recurrence and survival. METHODS: The study is a retrospective analysis of patients in Singapore General Hospital who underwent complete resection for histologically proven tongue carcinoma from 2000 to 2002. The Tv was measured on staging T(2)-weighted magnetic resonance imaging datasets by semiautomated methods. RESULTS: Seventeen patients with a median follow-up duration of 57.9 months were studied. A wide range of volumes was noted in each T stage. The median time to relapse was 8.6 months for those with Tv > or = 13 cc but was not achieved for those with Tv < 13 cc. The hazard ratio comparing Tv > or = 13 cc versus <13 cc is 9.02 (95% confidence interval (CI) 1.70-47.94, P = 0.014). Of the seven deaths reported, five patients had Tv > or = 13 cc. The median overall survival was 15.8 months for those with Tv > or = 13 cc but was not achieved for those with Tv < 13 cc. The hazards of death for Tv > or = 13 cc was 3.91 times that of Tv < 13 cc (95% CI 0.86-17.86, P = 0.078). CONCLUSION: Tongue cancer Tv measurement allows a more refined and accurate assessment of tumour status. This can be a possible prognostic indicator and be used in a novel staging method for the future.

Correlation between MR imaging-derived nasopharyngeal carcinoma tumor volume and TNM system.

PURPOSE: To measure nasopharyngeal carcinoma tumor volume based on magnetic resonance images using a validated semiautomated measurement methodology and correlate tumor volume with TNM T classification. METHODS AND MATERIALS: The study population consisted of 206 consecutive nasopharyngeal carcinoma patients who had magnetic resonance imaging staging scans. Tumor volume was measured using a semisupervised knowledge-based fuzzy clustering algorithm. Patients were divided into 4 groups according to TNM T classification. The difference in tumor volumes among the various TNM T-classification groups was examined. RESULTS: The mean tumor volume in each T-classification group is as follows: T1, 8.6 mL +/- 5.0 (standard deviation [SD]); T2, 18.1 mL +/- 8.1 (SD); T3, 25.8 mL +/- 14.1 (SD); and T4, 36.2 mL +/- 18.9 (SD). The mean tumor volume increased significantly with advancing T classification (p < 0.0001). Tumor volume in a more advanced T group was significantly larger than that in an adjacent early T group (p < 0.01). CONCLUSION: Validated magnetic resonance imaging-based tumor volume shows positive correlation between tumor volume and advancing T-classification groups. It may be possible to incorporate tumor volume as an additional prognostic factor into the existing TNM system.

Improvement in cerebral hemodynamic parameters and outcomes after superficial temporal artery-middle cerebral artery bypass in patients with severe stenoocclusive disease of the intracranial internal carotid or middle cerebral arteries.

OBJECT: Both the older and the recent extracranial-intracranial (EC-IC) bypass trials for symptomatic carotid occlusion failed to demonstrate a reduction in stroke recurrence. However, the role of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass in patients with symptomatic intracranial stenoocclusive disease has been rarely evaluated. The authors evaluated serial changes in various cerebral hemodynamic parameters in patients with severe stenoocclusive disease of the intracranial internal carotid artery (ICA) or middle cerebral artery (MCA) and impaired cerebral vasodilatory reserve (CVR), treated by STA-MCA bypass surgery or medical treatment. METHODS: Patients with severe stenoocclusive disease of the intracranial ICA or MCA underwent transcranial Doppler (TCD) ultrasonography and CVR assessment using the breath-holding index (BHI). Patients with impaired BHI (< 0.69) were further evaluated with acetazolamide-challenge technitium-99m hexamethylpropyleneamine oxime ((99m)Tc HMPAO) SPECT. STA-MCA bypass surgery was offered to patients with impaired CVR on SPECT. All patients underwent TCD and SPECT at 4 ± 1 months and were followed up for cerebral ischemic events. RESULTS: A total of 112 patients were included. This total included 73 men, and the mean age of the entire study population was 56 years (range 23-78 years). (99m)Tc HMPAO SPECT demonstrated impaired CVR in 77 patients (69%). Of these 77 patients, 46 underwent STA-MCA bypass while 31 received best medical treatment. TCD and acetazolamide-challenge (99m)Tc HMPAO SPECT repeated at 4 ± 1 months showed significant improvement in the STA-MCA bypass group. During a mean follow-up of 34 months (range 18-39 months), only 6 (13%) of 46 patients in the bypass group developed cerebral ischemic events, as compared with 14 (45%) of 31 patients receiving medical therapy (absolute risk reduction 32%, p = 0.008). CONCLUSIONS: STA-MCA bypass surgery in carefully selected patients with symptomatic severe intracranial stenoocclusive disease of the intracranial ICA or MCA results in significant improvement in hemodynamic parameters and reduction in stroke recurrence.

Tongue carcinoma: tumor volume measurement.

PURPOSE: To validate the semiautomated methods of tongue carcinoma tumor volume measurement by comparing the conventional manual trace method with 2 semiautomated computer methods: seed growing and region deformation. MATERIALS AND METHODS: The study population consisted of 16 patients with histology-proven tongue carcinoma. Two head-and-neck radiologists independently measured the tumor volume demonstrated on pretreatment T2-weighted magnetic resonance data sets. The tumor volumes were measured using manual tracing and semiautomated seed growing and region deformation algorithm. Data were recorded for analysis of interoperator variance and interobserver reliability at volume and pixel levels. RESULTS: There was no significant difference between the manually traced volume and semiautomated segmentation volumes for both operators. No significant difference was found in interobserver variance among the 3 methods at volume level. However, there was significant difference between manual tracing and semiautomated segmentation methods in interobserver reliability at pixel level. CONCLUSION: The semiautomated methods could achieve satisfactory segmentation results. They could also reduce interoperator variance and obtain a higher interobserver reliability. This study validates the use of semiautomated volume measurement methods for tongue carcinoma.

Posttreatment imaging of the nasopharynx.

Nasopharyngeal carcinoma (NPC) is the most common epithelial tumor of the nasopharynx. Radiation therapy is the mainstay of treatment while surgery or chemotherapy is used in selected patients. NPC usually regresses after 3 months of radiation therapy. Nonetheless, a residual mass may be present following treatment and this does not necessarily indicate viable tumor. Imaging studies are often used in conjunction with clinical examination following treatment. While computed tomography (CT) is widely used due to its greater availability, less expensive, and less time consuming, MR imaging is now becoming the preferred modality. MR imaging is more capable than CT for identifying mature scarring, tumor recurrence and postradiation complications. However, MR imaging cannot reliably demonstrate mucosal recurrence or differentiate tumor recurrence from postradiation tissue changes. Familiarity with the imaging findings of various posttreatment changes, tumor recurrence and postradiation complications is essential for management of NPC. Comparison with previous images or imaging-guided biopsy facilitates definitive diagnosis.

Imaging of the nasopharynx and skull base.

The prerequisite for the correct diagnosis and accurate delineation of skull base lesions is familiarity with the complex anatomy of the skull base. Imaging plays a central role in the management of skull base disease because this region is often difficult to evaluate clinically. CT and MR imaging are complementary; they are often used together to demonstrate the full disease extent. This article focuses on the critical anatomy of theskull base and how this knowledge contributes to accurate disease assessment.

Indication of lower neck irradiation in nasopharyngeal carcinoma without nodal metastasis: the potential impact of tumor volume.

BACKGROUND: Elective radiation of lower neck is controversial for nasopharyngeal carcinoma (NPC) without lymph node metastasis (N0 disease). Tumor volume is an important prognostic indicator. The objective of this study is to explore the potential impact of tumor volume on the indication of the lower neck irradiation for N0-NPC, by a qualitative evaluation of the relationship between tumor volume and nodal metastasis. METHODS: Magnetic resonance (MR) images of 99 consecutive patients with NPC who underwent treatment were retrospectively reviewed. Primary tumor volumes of NPC were semi-automatically measured, nodal metastases were N-classified and neck level involvements were examined. Distributions of tumor volumes among N-category-based groups and distributions of N-categories among tumor volume-based groups were analyzed, respectively. RESULTS: The numbers of patients with N0 to N3 disease were 12, 39, 32, and 16, respectively. The volumes of primary tumor were from 3.3 to 89.6 ml, with a median of 17.1 ml. For patients with nodal metastasis, tumor volume did not increase significantly with the advancing of N-category (P > 0.05). No significant difference was found for the distribution of N1, N2, and N3 categories among tumor volume-based groups (P > 0.05). Nevertheless patients with nodal metastasis had significantly larger tumor volumes than those without metastasis (P < 0.05). Patients with larger tumor volumes were associated with an increased incidence of nodal metastasis. CONCLUSIONS: Certain positive correlations existed between tumor volume and the presence of nodal metastasis. The tumor volume (>10 ml) is a potential indicator for the lower neck irradiation for N0-NPC.

Cerebral hyperperfusion syndrome after superficial temporal artery-middle cerebral artery bypass for severe intracranial steno-occlusive disease: a case control study.

BACKGROUND: Intracranial stenoses carry increased risk for cerebral ischemia. We perform external carotid-internal carotid (EC-IC) artery bypass in our patients with severe stenosis of the intracranial internal carotid (ICA) or middle cerebral artery (MCA) with impaired cerebral vasodilatory reserve (CVR). OBJECTIVE: To evaluate cerebral hemodynamics and cerebral hyperperfusion syndrome (HPS) in patients who develop focal neurological deficits after EC-IC bypass surgery. METHODS: Patients with severe intracranial ICA or MCA stenosis and impaired CVR on transcranial Doppler (TCD) derived breath-holding index (BHI) were evaluated with acetazolamide-challenged technetium-99m hexamethylpropyleneamineoxime-single-photon emission computed tomography (SPECT). EC-IC bypass surgery was offered to patients with impaired CVR on SPECT. Close monitoring was performed in patients developing focal neurological deficits within 7 days of surgery. RESULTS: Of 112 patients with severe intracranial ICA/MCA stenosis, 77 (69%) showed impaired CVR and 46 (41%) underwent EC-IC bypass. Transient neurological deficits within 7 days of surgery developed in 8 (17%). HPS was confirmed by CT perfusion and/or SPECT in 7 cases. A strong correlation was observed between HPS and preoperative TCD-BHI values (0%, 6.3%, and 41% in patients with BHI 0.3-0.69, 0-0.3 and <0, respectively; P = .012). HPS patients showed more than a 50% increase in MCA flow velocity on TCD (compared with preoperative values) on the operated side (63.3% vs 3.3% on control side, P < .001). Meticulous control of blood pressure and hydration led to rapid and complete resolution of neurological deficits in all cases. CONCLUSION: Symptomatic cerebral HPS is common in the early postoperative period after EC-IC bypass surgery. Early diagnosis and appropriate management might prevent the complications of this syndrome.

Timing of recanalization after intravenous thrombolysis and functional outcomes after acute ischemic stroke.

BACKGROUND: Recanalization of occluded intracranial arteries remains the aim of intravenous (IV) tissue plasminogen activator (tPA) therapy in acute ischemic stroke (AIS). OBJECTIVE: To examine the timing and impact of recanalization on functional outcomes in AIS. DESIGN: A longitudinal cohort of consecutive IV tPA­treated patients with AIS from January 2007 through December 2010. Data were collected for demography, risk factors, stroke subtypes, blood pressure, and National Institutes of Health Stroke Scale scores. Early recanalization (ER) was identified by transcranial Doppler monitoring during the first 2 hours of treatment. Recanalization was reevaluated at 24 hours by computed tomographic angiography (CTA). Patients with ER and patent index artery at 24 hours on CTA were labeled as having persistent recanalization (PR). Recanalization at 24 hours on CTA regardless of transcranial Doppler status was labeled as CTR. Favorable outcome was defined as a modified Rankin Scale score of 0 to 1 at 3 months. SETTING: University hospital stroke center. PATIENTS: A total of 240 patients with AIS who underwent IV tPA treatment. RESULTS: Of 2238 patients with AIS, 240 (11%) received IV tPA. The median age was 65 years (range, 19-92 years) and 44% of the study group was male. The median National Institutes of Health Stroke Scale score was 17 (range, 3-35) and the median onset-to-treatment time was 149 minutes (range, 46-270 minutes). Of the 240 patients, 122 (50.8%) achieved favorable outcomes at 3 months. Data for ER, PR, and CTR were analyzed for 160 patients. Early recanalization was seen in 82 patients (51.3%); 67 cases (81.7%) had PR and 84 cases (52.5%) had CTR. National Institutes of Health Stroke Scale score at onset (odds ratio per 1-point increase, 0.938; 95% CI, 0.888-0.991), ER (odds ratio, 3.048; 95% CI, 1.537-6.046), PR (odds ratio, 5.449; 95% CI, 2.382-12.464), and CTR (odds ratio, 4.329; 95% CI, 2.131-8.794) were independent predictors of favorable outcomes. CONCLUSIONS: Intravenous tPA­induced arterial recanalization within the first 24 hours in AIS is a strong predictor of favorable outcomes at 3 months.

A survey of local preclinical and clinical medical students' attitudes towards radiology.

INTRODUCTION: This study compares the attitudes between preclinical and clinical medical students towards radiology, following the introduction of a new radiology curriculum for 1st year students. MATERIALS AND METHODS: Revision of the 1st year medical school curriculum for the academic year of 2008/9 with the inclusion of 13 one-hour formal radiology lectures integrated with each body system was done in an undergraduate Southeast Asian medical school. In the old curriculum, 1st and 2nd year medical students are not exposed to radiology. They received limited radiology teaching in their 3rd and 5th years with 2 one-hour lectures as part of their medicine and surgery rotations. In the 4th year, they have a one week non-examinable posting in radiology. A survey was administered to preclinical (new curriculum) and clinical (old curriculum) students. Survey responses were tabulated and attitudes between preclinical and clinical students were compared. RESULTS: More than half of the preclinical students (155 out of 270 students, 59%) and 90 out of 720 clinical students (12.5%) responded. Students exposed to the new curriculum had attended one or two dedicated radiology lectures and were considering radiology as a clinical elective. Both groups of students did not feel familiar with radiology as with other specialties, were not considering radiology as a career, but felt that radiology was interesting and important to the overall practice of medicine. CONCLUSIONS: Exposure of 1st year students to radiology increases their interest in the subject. Further intervention, fi ne-tuning of the curriculum and follow-up surveys will be carried out to see if this interest persists throughout their clinical years.

Imaging of carcinoma of the external auditory canal: a pictorial essay.

Carcinoma of the external auditory canal presents a challenge in management, largely due to limited experience in treating this rare disease and the lack of a universally accepted staging system. Prognosis is most dependent on the extent of local disease at presentation, while resection margin status is also a strong determinant of survival in post-operative patients. The intent of this pictorial essay is to review the pattern of tumour spread and highlight the value of imaging, particularly magnetic resonance imaging in pre-operative tumour mapping.

Tumour volume measurement in head and neck cancer.

Tumour volume is a significant prognostic factor in the treatment of malignant head and neck tumours. Studies of laryngeal and pharyngeal tumours have shown tumour volume to be an important predictor for tumour recurrence. Some studies (for instance nasopharyngeal carcinoma) have shown through multivariate modelling that tumour volume is a dominant covariate that overwhelms T stage, N stage and stage group. The results of these studies have prompted several investigators to suggest the inclusion of tumour volume as an additional prognostic factor in future revisions of the TNM staging system. This paper briefly reviews the TNM system as a staging tool, the measurement of tumour volume and how tumour volume could possibly be incorporated in the system or used as an additional prognostic factor.

Extraction of metastatic lymph nodes from MR images using two deformable model-based approaches.

We presented and evaluated two deformable model-based approaches, region plus contour deformation (RPCD), and level sets to extract metastatic cervical nodal lesions from pretreatment T2-weighted magnetic resonance images. The RPCD method first uses a region deformation to achieve a rough boundary of the target node from a manually drawn initial contour, based on signal statistics. After that, an active contour deformation is employed to drive the rough boundary to the real node-normal tissue interface. Differently, the level sets move a manually drawn initial contour toward the desired nodal boundary under the control of the evolvement speed function, which is influenced by image gradient force. The two methods were tested by extracting 33 metastatic cervical nodes from 18 nasopharyngeal carcinoma patients. Experiments on a basis of pixel matching to reference standard showed that RPCD and level sets achieved averaged percentage matching at 82-84% and 87-88%, respectively. In addition, both methods had significantly lower interoperator variances than the manual tracing method. It was suggested these two methods could be useful tools for the evaluation of metastatic nodal volume as an indicator of classification and treatment response, or be alternatives for the delineation of metastatic nodal lesions in radiation treatment planning.

The relationship between nasopharyngeal carcinoma tumor volume and TNM T-classification: a quantitative analysis.

Recent findings show that tumor volume is a significant prognostic factor for the treatment of nasopharyngeal carcinoma (NPC). The inclusion of tumor volume as an additional prognostic factor in the UICC TNM classification system was suggested; however, how tumor volume could possibly be incorporated is still unexplored. In this paper, we report a quantitative analysis on the relationship between NPC tumor volume and T-classification, using the data from 206 NPC patients. By T-classification and semi-automatic tumor volume measurement, the difference in tumor volumes among the various TNM T-classification groups was examined. In addition, a statistics-based analysis scheme, which used the T-classification as the "gold standard", was proposed to classify NPC tumors into volume-based groups to explore the possible links. The results show that NPC tumor volume has positive correlation with advancing T-classification groups and significant difference existed in the distribution of T-classification among various volume-based groups (P < 0.001). By the proposed statistical scheme, tumor volume could be included as an additional prognostic factor in the TNM framework, following validation studies.