Abdul Jalil Nordin

Segmenting CT images of bronchogenic carcinoma with bone metastases using PET intensity markers approach

Segmenting CT images of bronchogenic carcinoma with bone metastases using PET intensity markers approach Background. The evolution of medical imaging plays a vital role in the management of patients with cancer. In oncology, the impact of PET/CT imaging has been contributing widely to the patient treatment by its large advantages over anatomical imaging from screening to staging. PET images provide the functional activity inside the body while CT images demonstrate the anatomical information. Hence, the existence of cancer cells can be recognized in PET image but since the structural location and position cannot be defined on PET images, we need to retrieve the information from CT images. Methods. In this study, we highlight the localization of bronchogenic carcinoma by using high activity points on PET image as references to extract regions of interest on CT image. Once PET and CT images have been registered using cross correlation, coordinates of the candidate points from PET are fed into seeded region growing algorithm to define the boundary of lesion on CT. The region growing process continues until a significant change in bilinear pixel values is reached. Results. The method has been tested over eleven images of a patient having bronchogenic carcinoma with bone metastases. The results show that the mean standard error for over segmented pixels is 33% while for the under segmented pixels is 3.4%. Conclusions. Although very simple in implementation, region growing can result in good precision ROIs. The region growing method highly depends on where the growing process starts. Here, by using the data acquired from other modality, we tried to guide the segmentation process to achieve better segmentation results.

Monte Carlo Simulation on Breast Cancer Detection Using Wire Mesh Collimator Gamma Camera

This paper presents the preliminary results of the new low energy high resolution wire-mesh collimator gamma camera in mapping breast cancer cells, by employing 140 keV photons of Technetium-99 m radionuclide tracer. The complete model of photons propagation and detection, as well as the human cells activities are simulated using Monte Carlo N-Particle code. Abnormal cells of different tumor to background values are investigated, and the results from the conventional collimator and wire-mesh collimator are compared. The results are evaluated in terms of the collimator sensitivity and the contrast to background ratio. In our assessment, the wire mesh collimator gamma camera yields slightly better results than the multihole collimator for sensitivity, however produces insignificant performance in the contrast to background evaluation.

Imaging characteristics of extrapulmonary tuberculosis lesions on dual time point imaging (DTPI) of FDG PET/CT.

Introduction: This study aimed to evaluate the diagnostic value of dual time point imaging (DTPI) of 18F‐fluorodeoxyglucose (FDG) positron emission tomography/CT (PET/CT) for detecting the infective lesions in patients with extrapulmonary tuberculosis (EPTB).

Dual time point imaging of FDG PET/CT in a tuberculous spondylodiscitis

Dual Time Point Imaging (DTPI) technique is a specialised protocol adopted in 18F-Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) imaging. This technique is claimed to be useful in differentiating malignant and infective lesions. The authors adopted this technique in a patient diagnosed with tuberculous spondylodiscitis and psoas abscess which demonstrated higher Maximum Standardized Uptake Value (SUVmax) during initial scans as compared with those obtained on delayed scans. The SUVmax changes between the two time points are believed to be a valuable finding for chronic granulomatous infective lesions such as tuberculosis.

Systematic review on the accuracy of positron emission tomography/computed tomography and positron emission tomography/magnetic resonance imaging in the management of ovarian cancer: Is functional information really needed?

Ovarian cancer (OC) often presents at an advanced stage with frequent relapses despite optimal treatment; thus, accurate staging and restaging are required for improving treatment outcomes and prognostication. Conventionally, staging of OC is performed using contrast-enhanced computed tomography (CT). Nevertheless, recent advances in the field of hybrid imaging have made positron emission tomography/CT (PET/CT) and PET/magnetic resonance imaging (PET/MRI) as emerging potential noninvasive imaging tools for improved management of OC. Several studies have championed the role of PET/CT for the detection of recurrence and prognostication of OC. We provide a systematic review and meta-analysis of the latest publications regarding the role of molecular imaging in the management of OC. We retrieved 57 original research articles with one article having overlap in both diagnosis and staging; 10 articles (734 patients) regarding the role of PET/CT in diagnosis of OC; 12 articles (604 patients) regarding staging of OC; 22 studies (1429 patients) for detection of recurrence; and 13 articles for prognostication and assessment of treatment response. We calculated pooled sensitivity and specificity of PET/CT performance in various aspects of imaging of OC. We also discussed the emerging role of PET/MRI in the management of OC. We aim to give the readers and objective overview on the role of molecular imaging in the management of OC.

Cerebral glucose hypometabolism in Tick-Borne Encephalitis, a pilot study in 10 Patients

BACKGROUND Tick borne encephalitis (TBE) is an acute meningoencephalitis with or without myelitis caused by an RNA virus from the flavivirus family transmitted by Ixodes spp ticks. The neurotropic TBE virus infects preferentially large neurons in basal ganglia, anterior horns, medulla oblongata, Purkinje cells and thalamus. Brain metabolic changes related to radiologic and clinical findings have not been described so far. METHODS Here we describe the clinical course of 10 consecutive TBE patients with outcome assessment at discharge and after 12 month using a modified Rankin Scale. Patients underwent cerebral MRI after confirmation of diagnosis and before discharge. 18F-FDG PET/CT scans were performed within day 5 to day 14 after TBE diagnosis. Extended analysis of coagulation parameters by thrombelastometry (ROTEM® InTEM, ExTEM, FibTEM) was performed every other day after confirmation of TBE diagnosis up to day 10 after hospital admission or discharge. RESULTS All patients presented with a meningoencephalitic course of disease. Cerebral MRI scans showed unspecific findings at predilection areas in 3 patients. 18F-FDG PET/CT showed increased glucose utilization in one patient and decreased 18F-FDG uptake in seven patients. Changes in coagulation measured by standard parameters and thrombelastometry were not found in any of the patients. DISCUSSION Glucose hypometabolism was present in 7 out of 10 TBE patients reflecting neuronal dysfunction in predilection areas of TBE virus infiltration responsible for development of clinical signs and symptoms.

Segmentation of Extrapulmonary Tuberculosis Infection Using Modified Automatic Seeded Region Growing

In the image segmentation process of positron emission tomography combined with computed tomography (PET/CT) imaging, previous works used information in CT only for segmenting the image without utilizing the information that can be provided by PET. This paper proposes to utilize the hot spot values in PET to guide the segmentation in CT, in automatic image segmentation using seeded region growing (SRG) technique. This automatic segmentation routine can be used as part of automatic diagnostic tools. In addition to the original initial seed selection using hot spot values in PET, this paper also introduces a new SRG growing criterion, the sliding windows. Fourteen images of patients having extrapulmonary tuberculosis have been examined using the above-mentioned method. To evaluate the performance of the modified SRG, three fidelity criteria are measured: percentage of under-segmentation area, percentage of over-segmentation area, and average time consumption. In terms of the under-segmentation percentage, SRG with average of the region growing criterion shows the least error percentage (51.85%). Meanwhile, SRG with local averaging and variance yielded the best results (2.67%) for the over-segmentation percentage. In terms of the time complexity, the modified SRG with local averaging and variance growing criterion shows the best performance with 5.273 s average execution time. The results indicate that the proposed methods yield fairly good performance in terms of the over- and under-segmentation area. The results also demonstrated that the hot spot values in PET can be used to guide the automatic segmentation in CT image.

Disseminated tuberculosis infection: a ‘super’ 18F-FDG PET/CT appearance

A 28-year-old immigrant presented with a 2-week history of throbbing headache. Contrast-enhanced computed tomography (CECT) examination showed multiple brain abscesses. He is a known defaulter from miliary tuberculosis treatment. 18 F-FDG PET/CT demonstrated multiple visually high metabolic activity lesions disseminated in the brain, thorax, abdomen and pelvis [1]. The maximum standard uptake values (SUVmax) of these lesions were substantially > 3.0 and comparable to the uptake of FDGavid malignant lesions. These findings demand careful image interpretation implicating false-positive results [2, 3]. Our case illustrates the usefulness of 18 F-FDG PET/CT in mapping active tuberculous lesions which can be used for baseline study [4].

PET/CT in nononcological lung diseases: current applications and future perspectives

Positron emission tomography (PET) combined with computed tomography (CT) is an established diagnostic modality that has become an essential imaging tool in oncological practice. However, thanks to its noninvasive nature and its capability to provide physiological information, the main applications of this technique have significantly expanded. 18F-labelled fluorodeoxyglucose (FDG) is the most commonly used radiopharmaceutical for PET scanning and demonstrates metabolic activity in various tissues. Since activated inflammatory cells, like malignant cells, predominantly metabolise glucose as a source of energy and increase expression of glucose transporters when activated, FDG-PET/CT can be successfully used to detect and monitor a variety of lung diseases, such as infections and several inflammatory conditions. The added value of FDG-PET/CT as a molecular imaging technique relies on its capability to identify disease in very early stages, long before the appearance of structural changes detectable by conventional imaging. Furthermore, by detecting the active phase of infectious or inflammatory processes, disease progression and treatment efficacy can be monitored. This review will focus on the clinical use of FDG-PET/CT in nonmalignant pulmonary diseases. PET/CT is an imaging modality that could play a role in evaluation of inflammatory and infectious lung diseases http://ow.ly/8YGT302aVlS

Preliminary results from attenuation correction for MCNP-generated PET image

This paper presents the preliminary results of PET system simulation using Monte Carlo code. We also present the implementation of attenuation correction for MCNP-generated PET image. Using MCNP5 we constructed a data base for a uniform cylindrical source. The data obtained from the simulation were then used for PET image reconstruction. During the image reconstruction, calculated attenuation correction method was implemented to the PET raw data. This method was chosen due to the fact that our study involved homogeneous and simple geometry phantom.