Administration Of gadolinium-DTPA Research Articles

Timing of cardiovascular magnetic resonance imaging and diagnostic yield in patients with acute myocardial infarction with nonobstructive coronary arteries

Abstract Background Accurate diagnosis of the underlying cause of myocardial infarction (MI) without obstructive coronary artery disease (MINOCA) is crucial. Cardiovascular magnetic resonance (CMR) plays an important role in the work up of patients with MINOCA. However, the timing of performance of CMR may impact on the diagnosis yield. Purpose To establish the diagnostic yield of CMR in a large cohort of patients admitted with MINOCA based on the timing of referral to CMR. Methods All patients referred to CMR from January 2009 to February 2022 with MINOCA were included. Studies were performed on a 1.5 T or 3T scanners. SSFP cines, T2-weighted black-blood fat-sat images and DE-segmented GE IR images 10–15 minutes after iv gadolinium-DTPA administration (0.15mmol/kg) were performed in 3 long-axis and 11–15 parallel short-axis views. All images were reviewed and analyzed off-line with specialized post-processing software. Results A total of 203 patients (median age 49 years, 60% men) with MINOCA diagnosis were included. Main ECG alterations were ST-segment elevation (STE) (57%) and T wave inversion (19%). Mean peak high sensitivity (HS)-TnI levels were 3706pg/mL. Median time to CMR was 7 days (5–9 days). Mean LVEF was 58% (range 18–83%) and mean LVEDVi 77 mL/m2 (range 35–210 mL/m2). Regional wall abnormalities were present in 123 patients (62%). High signal in T2w images was detected in 153 cases (75%) and late gadolinium enhancement (LGE) in 143cases (71%). Final CMR diagnosis resulted in myocarditis in 46%, MI in 20%, Takotsubo in 18%, and other cardiomyopathies in 6.4%. CMR was normal in 15 patients and not conclusive in 1. When CMR was performed within 7 days of admission (median: 5 days (4–6 days); n: 116 patients), the distribution of diagnoses was myocarditis in 53%, MI in 20%, Takotsubo in 16%, other cardiomyopathies in 6% and normal CMR in 4%. Whereas, if CMR was performed after 7 days (median: 10 days (8–12 days); n: 87 patients), the diagnoses were as flows: myocarditis in 36%, MI in 22%, Takotsubo 20%, cardiomyopathies in 7%, not conclusive in 1% and normal CMR in 13% (Table 1). Conclusions CMR led to the underlying diagnosis of MINOCA in 92% of patients. Myocarditis was the most frequent diagnosis. The final diagnosis of myocarditis was more frequent when CMR was performed within 7 days with a lesser percentage of normal CMR. Funding Acknowledgement Type of funding sources: None.

Ferumoxytol-enhanced cardiovascular magnetic resonance detection of early stage acute myocarditis

BackgroundThe diagnostic utility of cardiovascular magnetic resonance (CMR) is limited during the early stages of myocarditis. This study examined whether ferumoxytol-enhanced CMR (FE-CMR) could detect an earlier stage of acute myocarditis compared to gadolinium-enhanced CMR.MethodsLewis rats were induced to develop autoimmune myocarditis. CMR (3 T, GE Signa) was performed at the early- (day 14, n = 7) and the peak-phase (day 21, n = 8) of myocardial inflammation. FE-CMR was evaluated as % myocardial dephasing signal loss on gradient echo images at 6 and 24 h (6 h- & 24 h-FE-CMR) following the administration of ferumoxytol (300μmolFe/kg). Pre- and post-contrast T2* mapping was also performed. Early (EGE) and late (LGE) gadolinium enhancement was obtained after the administration of gadolinium-DTPA (0.5 mmol/kg) on day 14 and 21. Healthy rats were used as control (n = 6).ResultsLeft ventricular ejection fraction (LVEF) was preserved at day 14 with inflammatory cells but no fibrosis seen on histology. EGE and LGE at day 14 both showed limited myocardial enhancement (EGE: 11.7 ± 15.5%; LGE: 8.7 ± 8.7%; both p = ns vs. controls). In contrast, 6 h-FE-CMR detected extensive myocardial signal loss (33.2 ± 15.0%, p = 0.02 vs. EGE and p < 0.01 vs. LGE). At day 21, LVEF became significantly decreased (47.4 ± 16.4% vs control: 66.2 ± 6.1%, p < 0.01) with now extensive myocardial involvement detected on EGE, LGE, and 6 h-FE-CMR (41.6 ± 18.2% of LV). T2* mapping also detected myocardial uptake of ferumoxytol both at day 14 (6 h R2* = 299 ± 112 s− 1vs control: 125 ± 26 s− 1, p < 0.01) and day 21 (564 ± 562 s− 1, p < 0.01 vs control). Notably, the myocardium at peak-phase myocarditis also showed significantly higher pre-contrast T2* (27 ± 5 ms vs control: 16 ± 1 ms, p < 0.001), and the extent of myocardial necrosis had a strong positive correlation with T2* (r = 0.86, p < 0.001).ConclusionsFE-CMR acquired at 6 h enhance detection of early stages of myocarditis before development of necrosis or fibrosis, which could potentially enable appropriate therapeutic intervention.

Delayed Hydrocephalus Following Embolization with Hydrogel Coils for an Unruptured Aneurysm at the Tip of the Basilar Artery:A Case Report

We report the case of a 62-year-old woman with delayed hydrocephalus following endovascular embolization with hydrogel coils for an unruptured aneurysm at the tip of the basilar artery. She underwent the first and second embolizations with bare platinum coils and matrix coils, respectively. However, recanalization and regrowth of the aneurysm was observed, and a successful third embolization with hydrogel coils(2 mm/4 cm×2)was performed. However, progressive ventricular enlargement was observed during 8 months after the third treatment. MRI with fluid-attenuated inversion recovery sequence showed edema in the perianeurysmal white matter, as well as marked communicating hydrocephalus. The aneurysmal wall was enhanced with the administration of gadolinium-DTPA. The cerebrospinal fluid(CSF)protein level was 113 mg/dL. A ventriculo-peritoneal shunt was placed, and the patient was discharged without symptoms. It was postulated that endovascular embolization with hydrogel coils causes inflammation of the aneurysmal wall and perianeurysmal white matter, followed by elevation of CSF protein and subsequent communicating hydrocephalus.

Reduced intracellular mobility underlies manganese relaxivity in mouse brain in vivo: MRI at 2.35 and 9.4 T

Using T 1-weighted MRI at two different magnetic field strengths, the enhanced longitudinal relaxivity due to paramagnetic manganese ions in mouse brain in vivo is shown to reflect reduced intracellular mobility. One day after systemic administration of manganese chloride, increases of the longitudinal relaxation rate ∆R1 in several brain regions are significantly higher at 2.35 T than at 9.4 T. The corresponding relaxivity ratios (100)r1/400)r1 = (100)∆R1/(400)∆R1 range from 2.4 (striatum) to 4.4 (cerebellar cortex). In contrast, the ∆R1 values after intraventricular administration of gadolinium-DTPA (Gd-DTPA) are not significantly different between both field strengths yielding (100)r1/(400)r1 ratios from 1.0 to 1.1. The same observation holds true for manganese and Gd-DTPA relaxivities in aqueous solution. The pronounced field strength dependence of manganese relaxivities indicates a reduced mobility of manganese ions in vivo by confinement to a viscous fluid compartment and/or due to macromolecular binding. Moreover, preferential enhancement of nerve cell assemblies by manganese ions and the observation of additional contrast enhancement by magnetization transfer suggest an intracellular localization of manganese. This is further supported by a slow release of manganese from nerve cells postmortem, which occurs despite a high permeability of damaged cellular membranes as demonstrated by a rapid uptake of extracellular Gd-DTPA.

Mechanical effects of midwall fibrosis in non-ischemic dilated cardiomyopathy

Background In patients with non-ischemic dilated cardiomyopathy (NIDCM), mid-wall fibrosis (MWF) is associated with a higher risk of hospitalizations and death from pump failure and sudden cardiac death. The mechanical effects of MWF remain unexplored. Strain measures derived from feature tracking-CMR (FT-CMR) have been validated against myocardial tagging. Methods Patients (n = 84, age: 57.7 ± 14.7 yrs, [mean ± SD], LVEF: 25.7 ± 11.1%) with newly diagnosed NIDCM underwent late gadolinium enhancement CMR (inversion-recovery technique 10 min after the administration of gadolinium-DTPA (0.1 mmol/kg). Peak systolic cir

抗アクアポリン4抗体のほか複数の自己抗体をともなった視神経脊髄炎の1例

We report a patient with optic neuropathy and longitudinally extensive myelitis associated with anti-aquaporin 4 (AQP4) antibody and other autoantibodies. An 89-year-old woman presented with progressive numbness and weakness of the extremities which had acutely developed. She also complained of neck pain and gait disturbance. The results of a general physical examination were unremarkable. Neurologic examination disclosed right optic atrophy, an absence of touch sensation, pain, and muscular weakness in all her extremities. Her deep tendon reflexes were decreased, and the Babinski sign was bilaterally positive. Immunoserologic study yielded positive titers for anti-nuclear antibody (ANA), anti-double-stranded DNA, anti-Sjögren syndrome (SS)-A, anti-SS-B, and anti-ribonucleoprotein (RNP) antibodies. A lumbar cerebrospinal fluid examination showed a protein concentration of 54 mg/dL, a glucose concentration of 50 mg/dL (simultaneous blood concentration, 140 mg/dL), and a cell count of 2/mm(3). Chest radiography revealed interstitial pneumonia. Magnetic resonance imaging (MRI) of the cervical spine showed spondylotic cervical canal stenosis with cord impingement. T2-weighted MR images demonstrated increased signal intensity extending from C2 to C6, while contrast enhancement was noted in T1-weighted MR images upon gadolinium-DTPA administration. We suspected longitudinally extensive myelitis associated with the autoimmune disorders systemic lupus erythematosus and Sjögren syndrome. After intravenous methylprednisolone administration, her neurologic abnormalities gradually decreased, while MRI no longer showed increased signal or contrast enhancement. Anti-AQP4 antibody titers were positive. We consider that this patient had a neuromyelitis optica (NMO) spectrum disorder which was associated with systemic autoimmune disease. The possibility of NMO should be considered in similar patients with autoimmune disease, and anti-AQP4 antibody should be assessed.

Effect of intravenous gadolinium-DTPA on diffusion-weighted imaging for prostate lesions and normal tissue at 3.0-Tesla magnetic resonance imaging

Post-contrast diffusion-weighted imaging (DWI) is occasionally necessary when the results of the pre-contrast DWI differ from that of the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), however, the effects of contrast material on DWI image and apparent diffusion coefficient (ADC) values have not been fully examined. To assess whether the administration of gadolinium-DTPA (Gd-DTPA) significantly affects the DWI of prostate lesions or normal tissue at the 3.0 Tesla magnetic resonance imaging (3.0 T MRI). Fifty-one patients with 52 prostate lesions, including 32 prostate cancer (25 in the peripheral zone [PZ] and seven that could not be confidently located) and 20 benign lesions (11 in PZ and nine in central grand [CG]), underwent echo-planar imaging (EPI)-DWI with b values of 0, 1000 s/mm(2) before and after administration of Gd-DTPA at 3.0 T MRI. Regions of interest (ROI) were drawn in all lesions, 42 normal PZ, 44 CG tissue and air to calculate the signal-to-noise ratio (SNR) and ADC values of lesions and normal tissue, and contrast-to-noise ratio (CNR) of lesions for pre- and post-contrast images. Statistical differences between pre- and post-contrast data were assessed by use of a paired t test. No significant differences between pre- and post-contrast images were found in the CNR of lesions and SNR of all the tissue except CG, which showed a statistically significant decline (9.6%, p < 0.0001) in SNR after contrast relative to the pre-contrast images. The post-contrast ADC values were statistically significantly lower than pre-contrast for prostate cancer (0.80 ± 0.11 mm(2)/s Vs 0.89 ± 0.12 mm(2)/s, p < 0.0001) and benign lesions (1.14 ± 0.30 mm(2)/s vs. 1.2 ± 0.29 mm(2)/s, p < 0.0001). No significant differences were detected for normal tissue. The administration of Gd-DTPA can slightly affect the DWI image quality of the prostate and reduce the ADC value of lesions at 3.0T MRI. Applications of post-contrast DWI require caution in interpretation.

Evaluation of kidney function in vasopressin-deficient rats by using dynumic enhanced MRI

Objective To evaluate the renal function response to vasopressin in obstructed and non-obstructed kidney in vasopressin-deficient rats by using dynamic enhanced MRI. Methods This study included 26 vasopressin-deficient Brattleboro(BB)rats.Unilateral ureteral obstruction(UUO) model was set up in 12 BB rats.After releasing UU0 24 h,treatment of AVP was given in 7 non-obstrueted and 7 obstructed BB rats for 6 d.Seyen normal Wistar rats and 7 BB rats were used as control.Dynamic enhanced MRl was performed at 0-60 min following the administration of GadoliniumDTPA(0.05 mmol/kg)and the mean relative signal intensity(RSI)was measured. Results BB rats RSI increase occurred during the first minute,with a maximum mean RSI of(149±10)%in cortex,(155±13)%in medulla and(146±13)%in pelvis.Then,a gradual decrease in the cortical RSI occurred,after which a small increase was observed in Phase 3.BB rats RSI patterns were different from Wistar rats.After AVP treatment,mean RSI of BB rats in cortex,medulla and pelvis reached a maximum of(180±6)%,respectively at 30 sec,followed by a fast decrease at 1 min.Then,RSI decreased gradually.Phase 3 demonstrated a moderate increase in medullary and a relative large increase in pelvic RSI until 30 min after injection,after which RSI returned to baseline.BB rats RSI patterns after AVP treatment were similar to that of Wistar rats.Cortical,medullary and pelvic mean RSI increased slowly compared to non UUO rats.In phase 3,mean RSI of all segments decreased gradually.UUO rats RSI patterns were different from non UUO rats.After AVP treatment in UUO rats,mean RSIs of all segments increased faster compared to UUO rats without AVP.Cortical mean RSI reached a maximum of(193±7)% at 2 mim Mean RSI of medulla were unchanged,but the pelvic mean RSI deereased gradually to a minimum of(77±5)%at 5 min.Phase 3 was characterized by a slight recovcry of all RSIs.UUO rats RSIs were recovered after AVP treatment.The renal blood flow(RBF)of UUO rats was decreased to(1.1±0.1)m1·min-1·100g-1,wherease the RBF was increased to (1.9±O.3)ml·min-1·100g-1 after injecting AVP. Conclusion Dynamic enhanced MRI may provide useful information for distinguishing between kidneys having changes in the renal vasopressin concentration and the kidneys suffer from the obstructed renal damage. Key words: Magnetic resonance image; Kidney function; Rrats brattleboro; Vasopressins

Assessment of myocardial infarction in mice by late gadolinium enhancement MR imaging using an inversion recovery pulse sequence at 9.4T.

PurposeTo demonstrate the feasibility of using an inversion recovery pulse sequence and to define the optimal inversion time (TI) to assess myocardial infarction in mice by late gadolinium enhancement (LGE) MRI at 9.4T, and to obtain the maximal contrast between the infarcted and the viable myocardium.MethodsMRI was performed at 9.4T in mice, two days after induction of myocardial infarction (n = 4). For cardiovascular MR imaging, a segmented magnetization-prepared fast low angle shot (MP-FLASH) sequence was used with varied TIs ranging from 40 to 420 ms following administration of gadolinium-DTPA at 0.6 mmol/kg. Contrast-to-noise (CNR) and signal-to-noise ratio (SNR) were measured and compared for each myocardial region of interest (ROI).ResultsThe optimal TI, which corresponded to a minimum SNR in the normal myocardium, was 268 ms ± 27.3. The SNR in the viable myocardium was significantly different from that found in the infarcted myocardium (17.2 ± 2.4 vs 82.1 ± 10.8; p = 0.006) leading to a maximal relative SI (Signal Intensity) between those two areas (344.9 ± 60.4).ConclusionDespite the rapid heart rate in mice, our study demonstrates that LGE MRI can be performed at 9.4T using a protocol similar to the one used for clinical MR diagnosis of myocardial infarction.

Postoperative mutism after removal of an anterior falcine meningioma

Postoperative mutism is rare. We present a 65-year-old man who had transient mutism after resection of anterior falx meningioma. Mild left hemiparesis and palmomental reflex on the right were the only abnormal signs on neurological examination. CT scan and MRI demonstrated a mass at the anterior one-third portion of the falx just superior to the corpus callosum. The mass enhanced homogenously with administration of gadolinium DTPA. The patient underwent surgical resection of the lesion and adjacent falx cerebri. The operation was uneventful. On the second postoperative day he became mute. He could follow verbal commands, and write and read. Postoperative CT scan revealed a hypodense area in the right frontal lobe including a part of the anterior cingulate cortex and the anterior part of the corpus callosum. Histopathological examination revealed a mixed meningioma. Ten days postoperatively, he began to say simple words, and three weeks later he could talk normally. We consider that lesion of the supplementary motor area (SMA) may be responsible for postoperative mutism.

MAGNETIC RESONANCE IMAGING CHARACTERISTICS OF PERIPHERAL NERVE SHEATH TUMORS OF THE CANINE BRACHIAL PLEXUS IN 18 DOGS

Magnetic resonance imaging (MRI) examinations from 18 dogs with a histologically confirmed peripheral nerve sheath tumor (PNST) of the brachial plexus were assessed retrospectively. Almost half (8/18) had a diffuse thickening of the brachial plexus nerve(s), six of which extended into the vertebral canal. The other 10/18 dogs had a nodule or mass in the axilla (1.2-338 cm3). Seven of those 10 masses also had diffuse nerve sheath thickening, three of which extended into the vertebral canal. The majority of tumors were hyperintense to muscle on T2-weighted images and isointense on T1-weighted images. Eight of 18 PNSTs had only minimal to mild contrast enhancement and many (13/18) enhanced heterogeneously following gadolinium DTPA administration. Transverse plane images with a large enough field of view (FOV) to include both axillae and the vertebral canal were essential, allowing in-slice comparison to detect lesions by asymmetry of structures. Higher resolution, smaller FOV, multiplanar examination of the cervicothoracic spine was important for appreciating nerve root and foraminal involvement. Short tau inversion recovery, T2-weighted, pre and postcontrast T1-weighted pulse sequences were all useful. Contrast enhancement was critical to detecting subtle diffuse nerve sheath involvement or small isointense nodules, and for accurately identifying the full extent of disease. Some canine brachial plexus tumors can be challenging to detect, requiring a rigorous multiplanar multi-pulse sequence MRI examination.

Indirect Magnetic Resonance Lymphangiography to Assess Lymphatic Function in Experimental Murine Lymphedema

Recently, indirect magnetic resonance lymphangiography with gadolinium (Gd) has been demonstrated to offer the potential for safe, high-resolution visualization of the lymphatic vessels, in addition to the lymph nodes. In this study, the potential utility of indirect Gd contrast magnetic resonance imaging of lymphatic vascular function was investigated in the murine tail. Functional imaging of healthy mice is contrasted with the findings in experimentally-induced lymphatic vascular insufficiency. Postsurgical lymphedema was experimentally created in the murine tail. Normal and lymphedematous mouse tails were imaged following direct subcutaneous administration of Gadolinium-DTPA, 0.1 mmol/kg. Images were obtained in axial and coronal planes with a T1-weighted spin echo inversion-recovery sequence. In the normal tail, both of the bilateral major collecting lymphatics were clearly visualized as the Gd tracer was cleared from the interstitial compartment. In contrast, the Gd tracer accumulated at the prior surgical site in the lymphedematous tail. Quantitative assessment of Gd clearance demonstrates that accumulation of Gd correlates with the impedance to lymph flow proximal to the site of surgical lymphatic ablation. Magnetic resonance is a feasible and reliable method to be applied to quantitative functional imaging of the lymphatic vasculature in experimental models of lymphedema.

Assessment of resting perfusion defects in patients with acute myocardial infarction: comparison of myocardial contrast echocardiography, combined first-pass/delayed contrast-enhanced magnetic resonance imaging and 99mTC-sestamibi SPECT

Information on the accuracy of both magnetic resonance imaging (MRI) and myocardial contrast echocardiography (MCE) for the identification of perfusion defects in patients with acute myocardial infarction is limited. We evaluated the accuracy of MRI and MCE, using Single Photon Emission Computed Tomography (SPECT) imaging as reference technique. Fourteen consecutive patients underwent MCE, MRI and 99mTc-MIBI SPECT after acute myocardial infarction to assess myocardial perfusion. MCE was performed by Harmonic Power Angio Mode, with end-systolic triggering 1:4, using i.v. injection of Levovist. First-pass and delayed enhancement MRI was obtained after i.v administration of Gadolinium-DTPA. At MCE, homogeneous perfusion was considered as normal and absent or "patchy" perfusion as abnormal. At MRI, homogenous contrast enhancement was defined as normal whereas hypoenhancement at first-pass followed by hyperenhancement or persisting hypoenhancement in delayed images was defined as abnormal. At MCE 153 (68%) of segments were suitable for analysis compared to 220 (98%) segments at MRI (p<0.001). Sensitivity, specificity and accuracy of MCE for segmental perfusion defects in these 153 segments were 83, 73 and 77%, respectively. Sensitivity, specificity and accuracy of MRI were 63, 82, and 77%, respectively. MCE and MRI showed a moderate agreement with SPECT (k: 0.52 and 0.46, respectively). The agreement between MCE and MRI was better (k: 0.67) that the one of each technique with SPECT. MCE and MRI may be clinically useful in the assessment of perfusion defects in patients with acute myocardial infarction, even thought MCE imaging may be difficult to obtain in a considerable proportion of segments when the Intermittent Harmonic Angio Mode is used.

Prospective evaluation of pectoralis muscle invasion of breast cancer by MR imaging

Assessment of pectoralis muscle invasion is important for treatment planning for breast cancer. We evaluated the usefulness of breast magnetic resonance (MR) imaging for the detection of tumor invasion of the pectoralis muscle in breast cancer patients. A total of 306 breast MR examinations were performed preoperatively. Three-dimensional gradient echo sequences, at a section thickness of 1.5 or 2 mm were obtained with administration of gadolinium-DTPA. All patients underwent surgery. In 33 breasts, disruption of the fat plane between tumor and muscle was noted. Seven of 33 cases showed muscle enhancement contiguous to enhanced tumors. Pathology reports indicated that 5 of 7 of the tumors involved muscle invasion. Of the 2 false positive cases, one showed muscle enhancement because of a previous biopsy, and the other was incorrectly interpreted as showing muscle enhancement. Of the 26 breasts which did not demonstrate muscle enhancement, none were found at surgery to have tumor involvement. Enhancement of the pectoralis muscle correlates well with muscle invasion, but there are a few potential pitfalls. Disruption of the fat plane between tumor and muscle, without muscle enhancement, might not indicate tumor involvement of the pectoralis muscle.

Left atrial myxoma diagnosed and characterized by cardiac magnetic resonance imaging

A 71 year old man was referred for MRI investigation of the heart. He had a history of progressive dyspnea. Due to his echocardiographical findings and the known history of permanent atrial fibrillation, his cardiologist suspected atrial thrombi. MRI investigation of the heart showed a left atrial mass pedunculated at the atrial septum which showed signal enhancement after intravenous administration of gadolinium-DTPA. Left atrial myxoma was suspected. The patient underwent surgery with resection of the tumor and patch-occlusion of the atrial septum. Histology confirmed a polypoid cardial myxoma.

Optimizing brain MRI protocols in the follow-up of patients with multiple sclerosis

The aim of our study was to determine whether T2-weighted (T2w) MRI of the brain could be performed immediately after the administration of gadopentetate dimeglumine (gadolinium DTPA) in patients with multiple sclerosis (MS) without a loss in image quality or diagnostic reliability. Sixteen patients with clinically diagnosed MS were included in the study. Twenty-four patients with various cerebral pathologies (14 patients with multiple lacunar lesions) were examined in order to exclude masking of T2 hyperintense lesions other than MS lesions. Images of 10 patients without pathological changes served as a control condition for the qualitative analysis. In these 50 patients, T1w and T2w MRI was performed before and after the administration of gadolinium DTPA. Signal intensities were measured within T2 hyperintense cerebral lesions, in T1-enhancing lesions and in normal appearing brain tissue on T2w turbo spin-echo (TSE) sequences. Both quantitative and qualitative analysis did not show significant differences between T2w pre- and postcontrast series. T2w MRI performed prior to and after the administration of gadolinium DTPA provides similar information in patients with MS. With a TR of 3.2 s, not a single lesion was obscured on T2w postcontrast series. Acquisition of T2w MR images immediately after the administration of gadolinium DTPA allows for shorter examination time and assures sufficient time for contrast enhancement in cerebral lesions with a disrupted blood-brain barrier.

Tl-201 brain SPECT in glomus jugulare tumor.

Despite limited sensitivity of Tl-201 brain SPECT in detecting infratentorial small neoplasms, a case of glomus jugulare tumor or nonchromaffin paraganglioma visualized on a Tl-201 tomographic study is reported. A 68-year-old man who underwent surgical resection of prostate cancer 2 years earlier was examined for a 6-month history of recurrent headaches, left-sided pulsatile tinnitus, and hearing loss. Magnetic resonance imaging (MRI) of the brain showed a small hypointense mass with enhancement after gadolinium-DTPA administration in the posterior cranial fossa at the level of the left jugular foramen. A possible glomus tumor was considered. Tl-201 brain SPECT showed a small focus of abnormal tracer accumulation in the left temporal area, adjacent to the cerebellopontine angle, with a lesion:contralateral normal region uptake ratio greater than 3. A digital angiographic scan revealed a glomus jugulare tumor in the left jugular foramen, which was confirmed by histopathologic examination after excision.

MR arthrography: pharmacology, efficacy and safety in clinical trials.

A meta-analysis was carried out of clinical trials published between 1987 and 2001 in respect of the clinical pharmacology and safety as well as the diagnostic efficacy of gadolinium-DTPA (Gd-DTPA) for direct intra-articular injection before MRI examination. Scientific papers (clinical, postmortem and experimental studies) and information from the manufacturer regarding intra-articular injection of Gd-DTPA that addressed questions of mode of action, optimal concentration and dose, elimination and safety were reviewed. Clinical studies were classified according to their study design. The sensitivity, specificity and accuracy of MR arthrography (MRA) were compared with a "gold standard" (arthroscopy, arthrotomy) and other radiological evidence for different joints. Fifty-two clinical studies of the overall 112 studies addressed aspects of diagnostic efficacy of MRA in patients or in healthy volunteers. The shoulder was the most assessed joint (29 of 52 studies). Good (>80%) or even excellent (90-100%) sensitivity, specificity and accuracy were found for MRA in most indications, especially for the shoulder and knee joints and induced extension of rotator cuff lesions, labrum abnormalities and postoperative meniscal tears. Two millimoles per liter has proven to be the best concentration for intra-articular administration of Gd-DTPA. After passive complete diffusion from the joint within 6-24 h, complete and rapid renal elimination takes place after intra-articular injection. Local safety proved to be excellent after intra-articular administration of Gd-DTPA. Regarding systemic tolerance almost no side effects have been reported, but the same safety considerations apply for intra-articular administration of Gd-DTPA as for intravenous injection. The diagnostic efficacy of intra-articular MRA in most clinical conditions affecting major joints is greater than that of plain MRI. In some diagnostic problems MRA achieves almost the same sensitivity and specificity as the surgical gold standard. Given a sterile application, the intra-articular administration of Gd-DTPA in a concentration of 2 mmol/l prior to MRI is a safe procedure.

Detection of Spontaneous Schwannomas by MRI in a Transgenic Murine Model of Neurofibromatosis Type 2

Spontaneous schwannomas were detected by magnetic resonance imaging (MRI) in a transgenic murine model of neurofibromatosis type 2 (NF2) expressing a dominant mutant form of merlin under the Schwann cell-specific PO promoter. Approximately 85% of the investigated mice showed putative tumors by 24 months of age. Specifically, 21% of the mice showed tumors in the intercostal muscles, 14% in the limb muscles, 7% in the spinal cord and spinal ganglia, 7% in the external ear, 14% in the muscle of the abdominal region, and 7% in the intestine; 66% of the female mice had uterine tumors. Multiple tumors were detected by MRI in 21% of mice. The tumors were isointense with muscle by T1-weighted MRI, showed strong enhancement following administration of gadolinium-DTPA, and were markedly hyperintense by T2-weighted MRI, all hallmarks of the clinical manifestation. Hematoxylin and eosin staining and immunohistochemistry indicated that the tumors consisted of schwannomas and Schwann cell hyperplasias. The lesions stained positively for S-100 protein and a marker antigen for the mutated transgenic NF2 protein, confirming that the imaged tumors and areas of hyperplasia were of Schwann cell origin and expressed the mutated NF2 protein. Tumors were highly infectable with a recombinant herpes simplex virus type 1 vector, hrR3, which contains the reporter gene, lacZ. The ability to develop schwannoma growth with a noninvasive imaging technique will allow assessment of therapeutic interventions.

Humeral hydatid cyst complicated with extraosseous involvement: a case of unusual location of echinococcosis

Hydatid disease is a parasitic disease most commonly caused by Echinococcus granulosus that seldom involves the skeleton and is still common in the countries of the temperate zones. We present an extremely rare case report of a young patient with humeral hydatid disease complicated with extraosseous involvement. Plain film of the left humerus demonstrated distortion of the axis, regional expansion of the humeral shaft with minimal thinning areas of the cortex. Additionally, numerous radiolucent areas of the humeral shaft were observed especially at the distal part of the bone. No calcification of the soft tissues was noticed. Computed tomography examination showed significant destruction of the trabecular bone of the humeral head and polycystic appearance of the bone marrow with regional calcifications into the lumen. Additionally, a large cystic lesion between medial and lateral head of the triceps muscle with some foci of calcifications were observed. Magnetic resonance imaging revealed the multiocular nature of the lesion into the humeral lumen with a cystic lesion involving the soft tissues of the upper arm. The cyst showed contrast enhancement at the pericyst capsule of the cyst after Gadolinium-DTPA administration.