Ahmed Abdel Khalek Abdel Razek

Invasive ductal carcinoma: correlation of apparent diffusion coefficient value with pathological prognostic factors

The aim of this study was to correlate the apparent diffusion coefficient (ADC) value of invasive ductal carcinoma with pathological prognostic factors. A prospective study was conducted on 59 untreated female patients (mean age 46 years) with invasive ductal carcinoma. All patients were examined at 1.5 Tesla using dedicated bilateral breast coil. They underwent diffusion weighted MR imaging of the breast using a single shot echo planar imaging with a b‐factor of 200 and 400 sec/mm2. Apparent diffusion coefficient (ADC) maps were reconstructed. The ADC value of the breast cancer was calculated and correlated with the pathologic prognostic factors (tumor size, grade and lymph nodes). The mean ADC values of invasive ductal carcinoma were significantly lower in patients with high grade, large breast cancer as well as those with axillary lymph nodes metastasis in a statistically significant way (p = 0.001 for the three factors). The mean ADC value of invasive ductal carcinoma was correlated with histologic grade (r = −0.675, p = 0.001), tumor size (r = 0.504, p = 0.001) and showed lower ADC values with positive lymph node metastasis. Apparent diffusion coefficient value is correlated with pathological parameters of invasive ductal carcinoma. The lower ADC values are associated with higher histological grade, larger tumor size and presence of axillary lymph nodes. So, the ADC value can be considered as a promising prognostic parameter that may identify highly aggressive breast cancer. Copyright

Image Quality and Radiation Dose of Dual-Energy CT of the Head and Neck Compared with a Standard 120-kVp Acquisition

BACKGROUND AND PURPOSE: DECT offers additional image datasets with potential benefits, but its use for H&N imaging is not justified unless image quality is preserved without increased radiation dose. The aim of this work was to compare image quality and radiation dose between a DE-derived WA image dataset and a standard SECT acquisition of the H&N. MATERIALS AND METHODS: Thirty-two patients underwent DECT of the H&N (tube voltages 80 and Sn140 kVp) and were compared with the last 32 patients who underwent standard SECT (120 kVp) on the same dual-source scanner. WA images from the 2 DE tubes were compared with images obtained with an SE mode. Radiation doses and attenuation measurements of the internal jugular vein, submandibular gland, and sternomastoid and tongue muscles were compared. Objective image noise was compared at 5 anatomic levels. Two blinded readers compared subjective image quality by using 5-point grading scales. RESULTS: CTDIvol was 12% lower with DE than with SECT, a difference of 1.5 mGy, (P < .0001). Objective noise was not significantly different between DE and SECT at any of the anatomic levels (P > .05). No significant differences in attenuation measurements were observed between DE and SECT (P > .05). No significant differences in subjective image quality scores were observed between DE and SECT at any of the 5 anatomic levels (P > .05). CONCLUSIONS: DE-derived WA images of the H&N are equivalent to standard SE acquisitions and thus can be used for routine diagnostic purposes. Multiple additional image datasets can be obtained with no radiation dose penalty.

Disorders of Cortical Formation: MR Imaging Features

SUMMARY: The purpose of this article was to review the embryologic stages of the cerebral cortex, illustrate the classification of disorders of cortical formation, and finally describe the main MR imaging features of these disorders. Disorders of cortical formation are classified according to the embryologic stage of the cerebral cortex at which the abnormality occurred. MR imaging shows diminished cortical thickness and sulcation in microcephaly, enlarged dysplastic cortex in hemimegalencephaly, and ipsilateral focal cortical thickening with radial hyperintense bands in focal cortical dysplasia. MR imaging detects smooth brain in classic lissencephaly, the nodular cortex with cobblestone cortex with congenital muscular dystrophy, and the ectopic position of the gray matter with heterotopias. MR imaging can detect polymicrogyria and related syndromes as well as the types of schizencephaly. We concluded that MR imaging is essential to demonstrate the morphology, distribution, and extent of different disorders of cortical formation as well as the associated anomalies and related syndromes.

Diffusion-Weighted Magnetic Resonance Imaging of Head and Neck

Our aim was to review the clinical applications of diffusion-weighted magnetic resonance imaging in the head and neck. Diffusion-weighted magnetic resonance imaging plays a role in the differentiation of benign from malignant head and neck tumors, squamous cell carcinoma from lymphoma, and metastatic from benign lymphadenopathy as well as in the selection of the biopsy site. It can be used for the differentiation of recurrent tumors from posttreatment changes and in monitoring the patient after radiotherapy. It helps in the differentiation of necrotic tumors from abscesses. Additionally, it can be used for the diagnosis and grading of diffuse autoimmune diseases, such as Sjogren and Graves diseases.

Lesions of the Petrous Apex: Classification and Findings at CT and MR Imaging

The petrous apex is a complex region of the central skull base that is surrounded by a number of important vascular and neural structures and can be home to a wide range of disease processes. Lesions arising in or spreading to the petrous apex cause varied and occasionally severe clinical sequelae, which typically result from mass effect or direct invasion of the cranial nerves, brainstem, or internal carotid artery. Because the petrous apex is not amenable to direct examination, cross-sectional imaging with computed tomography and magnetic resonance (MR) imaging plays an important role in diagnosis and characterization of lesions occurring there. Petrous apex lesions can be classified on the basis of their origin into the following categories: developmental lesions, inflammatory lesions, benign tumors, malignant tumors, vascular lesions, and osseous dysplasias. The most common lesions arising in the petrous apex are cholesterol granulomas, which can be reliably diagnosed with MR imaging due to their high signal intensity on both T1-weighted images and T2-weighted images. In addition, one should also be familiar with anatomic variants or pseudolesions in the petrous apex that can be mistaken for pathologic conditions.

Parasitic Diseases of the Central Nervous System

This article reviews the characteristic imaging appearances of parasitic diseases of the central nervous system, including cysticercosis, toxoplasmosis, cystic echinococcosis, schistosomiasis, amebiasis, malariasis, sparganosis, paragonimiasis, and American and African trypanosomiases. Routine precontrast and postcontrast MR imaging helps in localization, characterization, delineation of extension, and follow-up of the parasitic lesions. Moreover, recently developed tools, such as diffusion, perfusion, and MR spectroscopy, help to differentiate parasitic diseases of the central nervous system from simulating lesions. Combining imaging findings with geographic prevalence, clinical history, and serologic tests is required for diagnosis of parasitic diseases of the central nervous system.

Comparison of dual-energy CT-derived iodine content and iodine overlay of normal, inflammatory and metastatic squamous cell carcinoma cervical lymph nodes

AbstractObjectivesTo evaluate whether dual-energy computed tomography (DECT)-derived iodine content and iodine overlay could differentiate between normal, inflammatory and metastatic squamous cell carcinoma (SCC) cervical lymph nodes.MethodsThis study was approved by the institutional review board. Sixteen patients with normal lymph nodes, 20 patients with enlarged nodes draining deep cervical inflammations and 23 patients with pathologically proved metastatic SCC nodes who underwent contrast enhanced DECT were retrospectively identified. Iodine content and overlay of 36 normal, 43 inflammatory and 52 metastatic lymph nodes were calculated using circular regions of interest and compared among the three groups. A receiver operating characteristic (ROC) curve was used to determine the sensitivity and specificity of iodine content and overlay for diagnosis of metastatic nodes.ResultsIodine content (mg/ml) was significantly lower for metastatic lymph nodes (2.34 ± 0.45) than for normal (2.86 ± 0.37) and inflammatory (3.53 ± 0.56) lymph nodes, P < 0.0001. Iodine overlay (HU) was also significantly lower for metastatic lymph nodes (47 ± 11.6) than normal (57.4 ± 8.2) and inflammatory nodes (69.3 ± 11.5), P < 0.0001. The areas under the ROC curve for iodine content and iodine overlay were 0.923 and 0.896.ConclusionsDECT-derived iodine content and overlay differ significantly among normal, inflammatory and metastatic SCC cervical lymph nodes.Key points• Derived iodine content can be calculated from contrast-enhanced dual-energy CT. • Derived iodine content and iodine overlay could help characterise cervical lymph nodes. • Iodine parameters were significantly lower in metastatic lymph nodes than normal/inflammatory lymph nodes. • Iodine content appears more sensitive than iodine overlay for lymph node characterisation.

Role of diffusion-weighted magnetic resonance imaging in characterization of renal tumors.

Objective: To evaluate the role of diffusion-weighted magnetic resonance (MR) imaging in the characterization of renal tumors. Materials and Methods: Prospective study was conducted on 52 consecutive patients (24 males and 28 females) with renal tumor. They underwent diffusion-weighted echo planar MR imaging of the abdomen with b-factor of 0 and 800 seconds/mm2. The apparent diffusion coefficient (ADC) value of the renal tumor was calculated and correlated with histopathological results. Results: The mean ADC value of malignant renal tumors (1.56 ± 0.26 × 10−3 mm2/s) was significantly different (P = 0.001) from that of benign tumors (1.87 ± 0.50 × 10−3 mm2/s). Selection of 1.84 × 10−3 mm2/s as a cutoff point of ADC value to predict renal malignancy revealed accuracy of 89%, sensitivity of 89%, and specificity of 89%. The cutoff point of ADC value to differentiate renal cell carcinoma (RCC) from other malignancy (1.15 × 10−3 mm2/s) revealed 72% accuracy, 95% sensitivity, 50% specificity. The cutoff point of ADC value used to differentiate clear and papillary RCC from other subtypes of RCC was 1.84 × 10−3 mm2/s with an accuracy of 89%, sensitivity of 89%, and specificity of 89%. Conclusion: Apparent diffusion coefficient value can differentiate benign from malignant renal tumors and may be helpful for the differentiation of the histologic subtypes of RCC.

MR spectrsocopy of head and neck cancer

The aim of this review is to discuss the technique and potential applications of magnetic resonance spectroscopy (MRS) in head and neck cancer. We illustrate the technical issues related to data acquisition, post processing and interpretation of MRS of head and neck lesions. MRS has been used for differentiation of squamous cell carcinoma from normal tissue. The main potential clinical application of proton MRS ((1)H-MRS) is monitoring patients with head and neck cancer undergoing therapy. Pretreatment prediction of response to therapy can be done with phosphorus MRS ((31)P-MRS). Although performance of MRS of head and neck is challenging, technological advances in both software and hardware has the potential to impact on the clinical management of patients with head and neck cancer.

Assessment of soft tissue tumours of the extremities with diffusion echoplanar MR imaging

PurposeThis study assessed soft tissue tumours of the extremities with diffusion echo-planar magnetic resonance (MR) imaging.Materials and methodsWe carried out a retrospective study of 37 patients (22 male, 15 female; age range 4–68 years; mean age 41 years) with a soft tissue mass. Diffusion-weighted magnetic resonance (MR) imaging was done using echo-planar imaging (EPI) with b factor of 0.500 and 1,000 mm2/s. The apparent diffusion coefficient (ADC) map was reconstructed with calculation of the ADC values of the mass.ResultsThe mean ADC value of the malignant tumours was 1.02±0.03×10−3mm2/s and that of benign masses 1.54±0.03×10−3mm2/s. There was a significant difference in the ADC values between malignant soft tissue tumours and benign masses (p<0.001) and within different grades of malignancy (p<0.02). Selection of 1.34×10−3 mm2/s as a threshold ADC value for differentiating malignant soft tissue tumours from benign masses resulted in an accuracy of 91%, sensitivity of 94%, specificity of 88% and area under the curve of 0.869. There was a significant difference in the ADC value between well- and poorly differentiated malignancies (p=0.001).ConclusionsDiffusion-weighted echo-planar MR imaging is a promising noninvasive modality that may be helpful in differentiating malignant soft tissue tumours from benign masses as well as in grading malignancy.RiassuntoObiettivoQuesto studio ha esaminato i tumori dei tessuti molli delle estremità tramite risonanza magnetica (RM) ecoplanare in diffusione.Materiali e metodiAbbiamo condotto uno studio retrospettivo su 37 pazienti (22 maschi, 15 femmine; range d’età, 4–68 anni; età media, 41 anni) con una massa nei tessuti molli. L’imaging RM con pesatura in diffusione è stato effettuato utilizzando immagini eco-planari (EPI) con fattore b uguale a 0,500 e 1000 mm2/s. è stata ricostruita la mappa del coefficiente di diffusione apparente (ADC) con calcolo dei valori di ADC della lesione.RisultatiIl valore medio di ADC dei tumori maligni è stato pari a 1,02±0,03×10−3 mm2/s, mentre quello delle lesioni benigne pari a 1,54±0,03×10−3 mm2/s. Abbiamo osservato una differenza significativa nei valori di ADC tra tumori dei tessuti molli e lesioni benigne (p<0,001), e con differenti gradi di malignità (p<0,02). La scelta di un valore di ADC pari a 1,34×10−3 mm2/s come soglia per differenziare i tumori maligni dalle lesioni benigne ha dimostrato una accuratezza del 91%, una sensibilità del 94%, una specificità dell’88% ed un’area sotto la curva (AUC) pari a 0,869. è stata osservata una differenza significativa dei valori di ADC tra lesioni ben differenziate e lesioni poco differenziate (p=0,001).ConclusioniL’imaging RM eco-planare pesato in diffusione è una promettente metodica non-invasiva che potrebbe aiutare nella differenziazione i tumori maligni dei tessuti molli dalle lesioni benigne, così come nella definizione del grado di malignità.