Seok-Nam Yoon

Specific DWI lesion patterns predict prognosis after acute ischaemic stroke within the MCA territory

Background: Apart from diffusion-weighted imaging (DWI) lesion volume and diffusion–perfusion mismatching, there is limited information about neuroradiological predictors of early prognosis after an ischaemic stroke. This study sought to identify specific DWI lesion patterns that would help prediction of early prognosis of three different endpoints: unstable hospital course, recurrence of stroke, and poor neurological outcome at 90 days after ischaemic stroke. Methods: A total of 426 patients with acute cerebral infarcts within the middle cerebral artery territory were prospectively studied. Using the DWI data the patients were divided into six groups (territorial, other cortical, small superficial, internal border zone, small deep, and other deep infarcts), and any recurrent strokes and prognosis over the following 90 days were recorded. Results: DWI lesion pattern was a stronger and more consistent independent outcome predictor than DWI lesion volume. The specific DWI lesion patterns associated with each endpoint differed. An unstable hospital course was frequently observed in patients with internal border zone infarcts, whereas recurrent strokes after the index stroke were commoner in those who had small superficial infarcts (p<0.05 in both cases). Similarly, poor outcome after stroke was associated with older age, severe neurological deficits at admission, and a DWI lesion pattern showing internal border zone infarcts. Conclusions: The results of the present study indicate that the DWI lesion pattern may help in recognition of the likely differences in the early prognostic endpoints after ischaemic stroke, and DWI analysis may guide targeted interventions to prevent negative outcomes.

Cardiac 123I-MIBG scintigraphy in patients with drug induced parkinsonism

Cardiac sympathetic dysfunction was investigated using 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy in 20 patients with drug induced parkinsonism (DIP). The mean heart to mediastinum ratio was significantly greater in patients with DIP than in those with Parkinson’s disease (mean (SD): 2.07 (0.39) v 1.28 (0.15), p<0.001). MIBG uptake was not different between the DIP patients and controls. Two DIP patients whose MIBG uptake was significantly reduced showed persistent parkinsonism and responded dramatically to levodopa.

Cardiac 123I-MIBG scintigraphy in patients with essential tremor

In some cases, it is difficult to differentiate essential tremor (ET) from Parkinsons disease (PD), especially in the early stages of the disease. We investigated cardiac sympathetic dysfunction using 123I‐metaiodobenzylguanidine (MIBG) myocardial scintigraphy in 22 patients with ET, in comparison with early PD and tremor‐dominant PD (TDPD). The mean ratio of 123I‐MIBG uptake in the region of interest in the heart to that in the mediastinum (H/M ratio) was significantly greater in patients with ET (1.99 ± 0.21) than in those with either TDPD (1.28 ± 0.11) or early PD (1.28 ± 0.17; each P < 0.001). The H/M ratio in all patients with ET was greater than two standard deviations above the range of the ratio in the patients with early PD or TDPD.

Abnormal bone scan in an adult with osteopoikilosis

AbstractOsteopoikilosis is rare, autosomal dominant bone disorder diagnosed by radiologic features. The findings include multiple small, circumscribed round areas of increased bone density distributed symmetrically in a periarticular location. The lesions cluster at the ends of long bones, around th

Imaging of malignant lymphomas with F-18 FDG coincidence detection positron emission tomography.

Purpose The authors evaluated the utility of F-18 fluorodeoxyglucose (FDG) coincidence detection (CoDe) positron emission tomography (PET) for staging, post-treatment evaluation, and follow-up assessment of patients with malignant lymphomas. Materials and Methods Fifty-eight patients with histologically proved malignant lymphomas (4 Hodgkin’s disease, 54 non-Hodgkin’s lymphoma) underwent CoDe PET using F-18 FDG. CoDe PET was performed using a dual-head gamma camera equipped with coincidence detection circuitry. Of the 87 CoDe PET studies, 26 were performed for staging, 38 for post-treatment evaluation, and 23 for follow-up evaluation of recurrence. The entire trunk, from the cervical to the inguinal regions, or selected regions were scanned with the patient in the supine position. No attenuation correction was made and reconstruction was performed using filtered backprojection rather than iterative reconstruction. CoDe PET findings were compared with corresponding results of computed tomographic (CT) and magnetic resonance imaging (MRI), tissue biopsy, or clinical follow-up. Results For staging, 52 sites were positive on CoDe PET or CT–MRI. CoDe PET detected 49 sites (94%), and CT–MRI showed 47 sites (90%). CoDe PET detected five more lymphomatous lesions and missed three lesions. For post-treatment evaluation, CoDe PET showed a positive predictive value of 100% and a negative predictive value of 83%, but the validated cases numbered only 11. For follow-up for recurrence, CoDe PET had a negative predictive value of 90%, but frequent false-positive findings were noted in the head and neck region as a result of underlying inflammatory changes. Conclusions For staging, FDG CoDe PET alone without attenuation correction is not sensitive enough to be used as an independent imaging method, especially for small abdominal lesions. However, it appears to be an accurate method for assessing residual disease and for patient follow-up.

18F-FDG imaging of the primary breast leiomyosarcoma and follow-up lung metastasis.

A 46-year-old woman presented with a large left breast mass. FDG PET/CT demonstrated a large left breast mass (SUV = 28). Preoperative biopsy showed malignant sarcoma. Modified radical mastectomy was performed. Immunohistochemical analysis using h-caldesmon and smooth muscle actin staining established the diagnosis of primary breast leiomyosarcoma. Despite intensive chemotherapy, 3-month follow-up PET/CT revealed a large lung metastasis suggesting aggressiveness and poor response to chemotherapy. Primary leiomyosarcoma of the breast is extremely rare and difficult to diagnose before excisional surgery because of the need for immunohistochemical staining to confirm the diagnosis.

False negative F-18 FDG PET/CT in nonsmall cell lung cancer bone metastases.

Tc-99m MDP bone scintigraphy is frequently performed for suspected skeletal metastases in lung cancer. F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has also proved useful for staging nonsmall cell lungcancer, and it offers superior spatial resolution and improved specificity for bone metastases. Although F-18 FDG-PET is superior to Tc-99m MDP bone scintigraphy for the detection of bone metastases, the sensitivity for sclerotic (osteoblastic) metastases by F-18 FDG PET/CT is lower than for lytic metastases. These bone metastases may not be glycolytically active and may be below the requisite tumor mass needed for FDG accumulation. We describe the case of false-negative F-18 FDG PET/CT findings in a 57-year-old woman who demonstrated sclerotic bone metastases from nonsmall cell lung cancer. F-18 fluoride PET demonstrates a similar uptake pattern as Tc-99m MDP.

Extensive Metastases on 18F-FDG PET/CT in Primary Lymphoepithelioma-Like Carcinoma of the Ovary.

We describe extensive metastatic lesions of very rare lymphoepithelioma-like carcinoma originating from the ovary assessed by F-FDG PET/CT. A 59-year-old woman presented with abdominal distention. Pelvis MRI demonstrated a large right ovarian malignant lesion with massive lymphadenopathy suggesting lymphoma. Patient underwent surgical removal. The lymphoepithelioma-like carcinoma arising from the ovary based on immunohistochemistry was pathologically confirmed. Multiple metastases including peritoneum, omentum, and lymph nodes were confirmed. F-FDG PET/CT for staging and evaluation of metastasis after operation showed multiple lymph node metastases. F-FDG PET/CT revealed hepatic metastasis in the dome region of the right liver besides multiple skeletal metastases.

Evaluation of an adrenal mass in a patient with lung cancer by FDG coincidence positron emission tomography using a dual-head gamma camera.

The proper management of primary lung cancer depends on accurate staging. Because a CT scan cannot reliably distinguish a metastasis from a benign nonfunctioning adrenal adenoma in most cases, many patients undergo percutaneous biopsy. The adrenal glands are common sites of metastases in patients with lung cancer. But most adrenal lesions incidentally discovered in patients with non-small-cell lung cancer are indeed benign. Camera-based FDG positron emission tomography (PET) may be as useful as conventional PET in the evaluation of adrenal metastases if the mass is within the resolution of camera-based PET (1.5 cm) or larger.