FDG-PET/CT-guided rebiopsy may find clinically unsuspicious transformation of follicular lymphoma.

AIM: The purpose of the study was to evaluate the clinical impact of fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) followed by a new biopsy from the site with maximum standardized uptake value (SUVmax) in case of high maximal SUV values, in detecting clinically unsuspected histologic transformations (HT) of follicular lymphoma (FL). METHODS: This retrospective study included all the patients who had undergone FDG-PET/CT during primary diagnosis or relapse of FL between 2010 and 2020 at Oulu University Hospital. RESULTS: The diagnosis changed from an indolent disease to a transformed lymphoma in >10% (7/63) of the patients who underwent diagnostic FDG-PET/CT. The HT risk associated with high SUVmax (>10) was 24% (7 of 29 performed biopsies). Four out of these seven patients with verified HT had no previous clinical suspicion of transformation. CONCLUSION: Our results suggest that a rebiopsy based on a high SUVmax in diagnostic FDG-PET/CT is valuable in detecting clinically unsuspected HT of FL.

Preoperative localization of the sensorimotor area using independent component analysis of resting-state fMRI.

Analysis of resting-state functional magnetic resonance imaging (fMRI) data is based on detecting low-frequency signal fluctuations in functionally connected brain areas. These synchronous fluctuations in resting-state networks have been observed in several studies with healthy subjects. In this study, we explored if independent component analysis (ICA) can be used to localize the sensorimotor area from resting-state fMRI data in patients with brain tumors. Finger-tapping activation task and resting-state blood-oxygenation-level-dependent fMRI data were acquired from 8 patients with brain tumors and 10 healthy volunteers. Sensorimotor task independent components (IC(task)) were used to verify resting-state independent components (IC(rest)) individually. In addition, sensorimotor IC(rest)s were compared between the groups and no significant differences were detected in volume, spatial correlation or temporal correlation. These results show that it is possible to localize a sensorimotor area from resting-state data using ICA in patients with brain tumors. This offers a complementary method for assessing the sensorimotor area in subjects with brain tumors who have difficulties in performing motor paradigms.

Enhancement of brain tumors in 0.23-T low-field MRI: comparison of edema attenuated inversion recovery (EDAIR) sequences with T1-weighted sequence.

RATIONALE AND OBJECTIVES: The aim of this study is to explore whether edema attenuated inversion recovery (EDAIR) sequences could be used to improve tumor contrast in contrast-enhanced low-field 0.23-Tesla magnetic resonance imaging (MRI) using 0.1 mmol/kg of gadolinium-based contrast agent. MATERIALS AND METHODS: Ten patients with brain tumors were examined by using the following contrast-enhanced sequences: T1-weighted spin echo, EDAIR with inversion time (TI) of 600 milliseconds, and EDAIR with TI of 800 milliseconds. Images were assessed both quantitatively and qualitatively. RESULTS: Results suggest that tumor contrast enhancement in low-field MRI can be improved without increasing contrast agent dose. EDAIR 600 appears to be optimal in most cases. CONCLUSIONS: This inversion recovery sequence could be applicable as an additional sequence in the imaging of metastases in low-field MRI, as well as imaging of any other enhancing brain tumors or lesions in low-field MRI.

Cerebral edema attenuated inversion recovery MR sequence in low magnetic field: a feasibility study.

RATIONALE AND OBJECTIVES: Minimally invasive neurosurgery requires methods to specify surgical boundaries of target tissue, such as brain tumors. This study investigated technical possibilities and clinical usefulness of adapting edema attenuated inversion recovery (EDAIR) pulse sequences to suppress magnetic resonance signal from cerebral edema in brain tumor patients. MATERIALS AND METHODS: A resistive 0.23-T magnetic resonance scanner with magnitude-encoded inversion recovery sequences was used. Twenty-eight separate scanning tests in 25 neurosurgical brain tumor patients were performed on the day before surgery. An inversion recovery sequence with several inversion times between 150 and 2,200 ms was tested. The same sequences were also used intraoperatively and postoperatively. RESULTS: T(1) relaxation time of brain edema varied from case to case. An inversion recovery sequence with an inversion time of 400-800 milliseconds attenuated brain edema and seemed to help in demarcating gross brain tumor for surgical resection. These features were helpful for the evaluation of resectable tumor tissue particularly using neuronavigation techniques. CONCLUSIONS: According to these preliminary findings, inversion recovery sequences supplement other imaging modalities and assist neurosurgeons in evaluating different surgical trajectories and in estimating brain tumor volume before craniotomy.

Effect of brain surgery on auditory and motor cortex activation: a preliminary functional magnetic resonance imaging study.

OBJECTIVE: The effect of glioma removal on blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) activation has not been widely documented. The aim of this preliminary study was to observe the effect of tumor resection on BOLD fMRI of the auditory and motor cortices. METHODS: Seven patients with gliomas underwent preoperative and early postoperative BOLD fMRI, and five of them underwent additional late postoperative BOLD fMRI. The auditory and motor cortices were localized with activation studies. A hemispheric activation index was used to quantify the relative extent of BOLD activation. RESULTS: The resection of a glioma with preoperative edema resulted in an increase from the preoperative to the early postoperative fMRI on auditory BOLD activation on the side of the tumor compared with the contralateral side. The same phenomenon was observed in one patient with motor BOLD activation. However, when no preoperative edema was present, a transient decrease in relative auditory BOLD activation was found. CONCLUSION: The results of this study suggest that the resection of a glioma with preoperative edema affecting the auditory and/or motor cortex may cause a transient increase in the BOLD response ipsilateral to the tumor. It seems that when the tumor is resected, the pressure on the brain, specifically on the affected auditory and/or motor cortex, decreases and the functional cortex becomes more easily detectable in BOLD fMRI.

Endplate degeneration observed on magnetic resonance imaging of the lumbar spine: correlation with pain provocation and disc changes observed on computed tomography diskography.

STUDY DESIGN: One hundred and three lumbar intervertebral discs (L3/4-L5/S1) of 36 patients with low back pain were examined with computed tomography (CT) diskography and magnetic resonance imaging (MRI). OBJECTIVES: To determine whether lumbar endplate degeneration correlates with the degree of disc degeneration or disc rupture and to determine if there is an association between pain provocation during diskography and lumbar endplate degeneration. SUMMARY OF BACKGROUND DATA: There have been numerous attempts to explain the pathogenesis of pain provocation during diskography, but the possibility of endplate degeneration as a source of pain has not been widely assessed. METHODS: One hundred and three lumbar intervertebral discs (36 L3/4, 36 L4/5, and 31 L5/S1 intervertebral discs) of 36 patients were examined. On the basis of MRI, the intervertebral discs were divided into four categories based on the degree of endplate degeneration. Based on pain provocation on diskography, the intervertebral discs were divided into three categories: no pain, indifferent/untypical pain, and familiar/typical pain. Based on disc degeneration and disc rupture, the intervertebral discs were divided into four categories in accordance with the Dallas Discogram Description: Grades 0-3 of both degeneration and rupture. RESULTS: There was a positive correlation between endplate degeneration and disc degeneration and a positive correlation between disc rupture and pain provocation, but there was no association between endplate degeneration and disc rupture and no correlation between endplate degeneration and pain provocation on diskography. CONCLUSIONS: This study showed a stronger association between endplate degeneration and disc degeneration than between endplate degeneration and disc rupture. The results indicate that the contrast injection during diskography reflects mainly pain of discogenic origin, whereas the possible pain associated with endplate damage cannot be depicted by CT diskography.