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Biomedical subjects

J Gaa

Publications and source records attributed to J Gaa.

At least 19 recordsLinked to original sources
PubMed2007

[Radiological diagnostics for iatrogenic retained foreign bodies after surgery].

Retention of surgical sponges is rare. They cause either an aseptic reaction without significant symptoms or an exudative reaction which results in early but non-specific symptoms. Even if there are no studies which compare the diagnostic accuracy of the different imaging modalities, CT seems to be the most promising tool to diagnose foreign bodies. However, apart from radio-paque markers there are no specific signs for the existence of surgical sponges in CT. Therefore, an experienced radiologist is needed to differentiate foreign bodies from morphologically quite similar differential diagnoses such as abscess and haematoma.

Diagnosis, Differential↗
PubMed2006

Assessment of the extent of metastases of gastrointestinal carcinoid tumors using whole-body PET, CT, MRI, PET/CT and PET/MRI.

OBJECTIVE: To assess the diagnostic value of whole-body positron emission tomography (PET), computed tomography (CT), magnetic resonance imaging (MRI), and the fusion of PET and CT (PET/CT) and PET and MRI (PET/MRI) in the detection of metastatic disease of gastrointestinal carcinoid tumors. MATERIALS AND METHODS: This prospective study included six patients with extensive nonresectable metastases of gastrointestinal carcinoid tumors which were consecutively examined from the base of the skull to the proximal thigh using a state-of-the-art PET/CT scanner and a 1.5 Tesla whole-body MRI scanner. PET was performed with a carbohydrated F-18-labeled somatostatin-receptor ligand ([ superset18 F]FP-Gluc-TOCA) using a Pico-3D PET scanner. CT was performed with a venous-dominant contrast-enhanced phase using a 16-slice CT scanner. MRI was performed with a coronal T2-weighted Half-Fourier Acquired Single-Shot Turbo Spin Echo (HASTE) sequence, a coronal T2-weighted Turbo-Short Tau Inversion-Recovery (STIR) sequence, a coronal T1-weighted Turbo Spin Echo (TSE) sequence and a high resolution axial T2-weighted TSE sequence. The data sets from PET and CT were fused automatically. The PET and MRI data sets were fused manually. Lesions were rated as metastases if they were not clearly identified as benign lesions according to standard radiological criteria. RESULTS: For PET, CT, MRI, PET/CT, and PET/MRI, the lesion-by-lesion based analysis showed an overall detection rate for liver metastases (n = 391) of 49.9% (P<.001), 37.1% (P<.001), 98.2%, 50.9% (P<.001) and 100%, for lymph node metastases (n = 37) of 91.9%, 83.8%, 64.9%, 100% and 97.3% and for osseous metastases (n = 12) of 100%, 8.3% (P<.005), 66.7%, 100% and 100%. CONCLUSIONS: PET as single modality revealed the most lymph node and osseous metastases. MRI as single modality revealed the most liver metastases. The combination of molecular/metabolic with anatomical/ morphological information improves the diagnostic accuracy for the detection of metastases in comparison to the single modalities. Whole-body PET/MRI is a very promising diagnostic modality for oncological imaging due to the missing radiation exposure and the high soft tissue resolution of MRI in contrast to CT.

Aged↗
PubMed2006

[Partial Budd-Chiari syndrome associated with a hypereosinophilic syndrome].

We report a rare case of hypereosinophilic syndrome associated with a partial obstruction of the hepatic veins (Budd-Chiari syndrome). The case was assessed by ultrasonic examination, computed tomography and magnetic resonance tomography. We postulate an association because endothelium damage and thrombosis is reported in hypereosinophilic syndromes. Elevated liver enzymes in a patient with hypereosinophilic syndrome could be associated with a Budd-Chiari syndrome.

Aged↗
PubMed2006

A rare case of primary rectal rhabdomyosarcoma in an adult.

We report an extremely rare case (1:200 000) of primary rectal rhabdomyosarcoma (RMS) in an adult. In the literature, this case report is the first one dealing with an adult patient. The diagnosis was assessed by computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), endoscopy and histological examination. Neoadjuvant systemic chemotherapy with adriamycin and isofosfamide followed by anterior rectum resection was performed. This article should implicate RMS as a rare differential diagnosis of atypical rectal tumours in adults.

Adult↗
PubMed2005

[Modern imaging for liver metastases from colorectal tumors].

Cross-sectional imaging modalities such as ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and Positron emission tomography (PET)/CT have benefited from rapid technical advances in recent years. In patients with colorectal tumors, multislice CT is the standard technique for preoperative evaluation and follow-up. It is faster than single-slice helical CT and allows for excellent 3D imaging of liver anatomy and tumor volumetry. The most accurate technique for detecting and characterizing focal liver lesions is MRI using state-of-the-art scanners and liver-specific contrast agents and should be used for preoperative evaluation of all possible surgical candidates. Whole-body FDG-PET and PET/CT are most useful in the detection of extrahepatic disease and may alter clinical management in up to 20% of patients by detecting extrahepatic spread of disease.

Colorectal Neoplasms↗
PubMed2005

Importance of diffusion-weighted imaging in the diagnosis of cystic brain tumors and intracerebral abscesses.

OBJECTIVE: It is often difficult to decide whether a cystic brain lesion is a tumor or an abscess by means of conventional MRI techniques. The immediate diagnosis of a brain abscess is important for the patient's outcome. Our goal was to study the ability of diffusion-weighted imaging and calculation of the apparent diffusion coefficient (ADC) to differentiate between these two pathologies. PATIENTS AND METHODS: Ten patients (five men, five women) with cystic brain lesions were examined with MRI. The ADC maps were calculated for each subject and the ADC value of each lesion was measured. Histology revealed glioblastoma multiforme in six patients and abscess in four patients. RESULTS: All brain abscesses showed markedly hyperintense signal changes on diffusion-weighted imaging, whereas the appearance of glioblastoma varied from slightly hyperintense to hypointense signal conversion. The mean ADC value calculated in the six patients with cystic brain tumor was: 2.05 x 10 (-3) mm(2)/s (1.38-2.88 x 10 (-3) mm(2)/s). The mean ADC value of the four patients with brain abscess was: 0.57 x 10 (-3) mm(2)/s (0.38-0.77 x 10 (-3) mm(2)/s). CONCLUSION: Diffusion-weighted imaging and calculation of ADC maps constitute a helpful tool to differentiate between cystic brain tumors and brain abscesses.

Adult↗
PubMed2004

Whole-body imaging with PET/MRI.

Whole-body positron emission tomography (PET) scanning with the radiolabeled glucose analogue 2-[fluorine-18]-fluoro-2-deoxy-D-glucose ( superset 18 F-FDG) can identify areas of cancerous involvement and distinguish malignant from benign lesions and therefore, plays an important role in the diagnosis and management of patients with cancer. PET facilitates the evaluation of metabolic and molecular characteristics of a wide variety of cancers, but it is limited in its ability to visualize anatomical structures. Whole-body magnetic resonance imaging (MRI) is a promising diagnostic modality for the diagnosis and management of patients with cancer, because of its high anatomical resolution. Whole-body PET and whole-body MRI allow to evaluate both the primary tumor and for the presence of metastasis at the same time. The combination of these two excellent diagnostic imaging modalities into a single scanner offers several advantages in comparison to PET and MRI alone. A hybrid PET/MRI facilitates the accurate registration of metabolic and molecular aspects of the diseases with exact correlation to anatomical findings, improving the diagnostic value in identifying and characterizing of malignancies and tumor staging. Thus, hybrid PET/MRI could be a very important diagnostic imaging modality in oncological applications in the decades to come, and possibly for use in cancer screening and cardiac imaging.

Fluorodeoxyglucose F18↗
PubMed2004

Comparison of intracranial 3D-ToF-MRA with and without parallel acquisition techniques at 1.5T and 3.0T: preliminary results.

PURPOSE: To evaluate the performance of four 3D-ToF magnetic resonance angiography (MRA) sequences with and without integrated parallel acquisition techniques (iPAT) at 1.5T and 3.0T in imaging intracranial vessels. MATERIAL AND METHODS: Seven volunteers and 5 patients (4 aneurysms, 1 AVM) underwent 3D-ToF-MRA at 1.5T (Magnetom Sonata) and 3.0T (Magnetom Trio) with and without parallel acquisition techniques (iPAT) using similarly designed 8-channel phased-array head coils. Imaging time of the pulse sequences was set to 7.15 and 7.35 min, respectively. Images were analyzed quantitatively by calculating signal-to-noise (SNR) and contrast-to-noise (CNR) ratios of proximal M2 segments and qualitatively by using a 5-point scale. RESULTS: SNR and CNR were significantly higher for both 3D-ToF sequences at 3.0T compared with both pulse sequences at 1.5T. The highest SNR and CNR were obtained at 3.0T without iPAT. However, because of a higher spatial resolution (matrix 512 x 640) visualization of small vessel details was best at 3.0T with iPAT. CONCLUSION: Intracranial 3D-ToF-MRA at 3.0T offers superior image quality compared with 1.5T, particular in the delineation of smaller vessels. In contrast to 1.5T, implementation of iPAT at 3.0T is of additional benefit since the high SNR available at 3.0T allows for higher spatial resolution without prolongation of measurement time.

Artifacts↗
PubMed2003

Posterior encephalopathy with vasospasm: MRI and angiography.

Posterior encephalopathy is characterised by headache, impairment of consciousness, seizures and progressive visual loss. MRI shows bilateral, predominantly posterior, cortical and subcortical lesions with a distribution. Our aim was to analyse the MRI lesion pattern and angiographic findings because the pathophysiology of posterior encephalopathy is incompletely understood. We report three patients with clinical and imaging findings consistent with posterior encephalopathy who underwent serial MRI including diffusion-weighted imaging (DWI) and construction of apparent diffusion coefficient (ADC) maps, and four-vessel digital subtraction angiography (DSA). DWI revealed symmetrical subcortical and cortical parieto-occipital high signal. High and also low ADCs indicated probable vasogenic and cytotoxic oedema. On follow-up there was focal cortical laminar necrosis, while the white-matter lesions resolved almost completely, except in the arterial border zones. DSA revealed diffuse arterial narrowing, slightly more marked in the posterior circulation. These findings suggest that posterior encephalopathy may in some cases be due to diffuse, severe vasospasm affecting especially in the parieto-occipital grey matter, with its higher vulnerability to ischemia. Cerebral vasospasm due to digitoxin intoxication, resulting in posterior encephalopathy, has not yet been described previously.

Adult↗
PubMed2003

Vasogenic edema in Bickerstaff's brainstem encephalitis: a serial MRI study.

The authors report serial MRI of a patient with Bickerstaff's brainstem encephalitis (BBE), disclosing caudal migration of an initial upper midbrain lesion. High apparent diffusion coefficient values imply a vasogenic rather than cytotoxic edema as the cause of the hyperintense signal changes on T2-weighted images.

Brain Edema↗
PubMed2001

[Ultrafast magnetic resonance tomography changes the standard in pancreas diagnosis].

BACKGROUND: Since the introduction of MRI, including imaging of the hepato-pancreatic duct system (MRCP) and 3D-MR angiography (3D-MRA), new pancreatic diagnostic procedures have been developed. METHODS AND PATIENTS: We report on 143 patients with benign and malignant diseases of the pancreas, who only received MRI preoperatively. All radiologic findings were confirmed intraoperatively. RESULTS: For resectability, MRI obtained sensitivity of 96.0% and specificity of 89.5% and for classification sensitivity of 99.1% and specificity of 95.2%. CONCLUSION: Based on our experience, the benign vs malignant nature of the disease, MRI is a safe and reliable method for pancreatic tumors being able to become the standard diagnostic procedure in the future.

Contrast Media↗
PubMed2001

Color Duplex sonography vs. computed tomography: accuracy in the preoperative evaluation of renal cell carcinoma.

PURPOSE: Accurate imaging is essential for correct operative planning and successful surgical intervention in renal cell carcinoma (RCC). Our objective was the comparison of color duplex sonography with spiral computed tomography (CT) and surgical-pathological findings in the evaluation of renal masses to determine tumor localization, size, tumor thrombus extent and lymph node metastases. METHODS: We evaluated 60 patients with a renal mass in a prospective study. Both color duplex sonography and CT were performed by different investigators without knowledge of the supposed diagnosis. The color Doppler findings were compared to CT and surgical pathological findings. RESULTS: The sensitivity of color duplex sonography in the detection of RCC and lymph node metastases is comparable to that of CT (100%). Color duplex sonography was superior in the detection of renal vein involvement. Color duplex sonography alone allowed correct planning of the surgical procedure without intraoperative changes in all patients. CONCLUSION: Duplex sonography provides exactly the same information as CT. Although duplex sonography is less expensive with lower exposure to radiation, most surgeons will still probably demand CT for diagnosis, especially as this method is unerring and duplex sonography highly depends on the expertise of the person using it.

Aged↗
PubMed2001

[Diagnosis of pancreas tumors: MRI or multidetector spiral CT?].

Recent technical advances in the field of abdominal MRI and multi-detector spiral-CT (MSCT) have resulted in improved diagnostic capabilities of pancreatic tumors. Preliminary data demonstrate slight advantages of MRI in the detection of liver metastases and papillary tumors as well as in the differential diagnosis of pancreatic masses while MSCT might be advantageous in the assessment of vascular infiltration, particular in uncooperative patients.

Diagnosis, Differential↗