Marcel Koenigkam-Santos

Lung nodule detection in a high-risk population: Comparison of magnetic resonance imaging and low-dose computed tomography

OBJECTIVE To investigate the potential of MRI for lung nodule detection in a high-risk population in comparison to low-dose CT. METHODS 49 participants (31 men, 18 women, 51-71 years) of the German Lung Cancer Screening and Intervention Trial (LUSI) with a cancer-suspicious lung lesion in CT were examined with non-contrast-enhanced MRI of the lung at 1.5 T. Data were pseudonymized and presented at random order together with 30 datasets (23 in men, 7 in women, 18-64 years) from healthy volunteers. Two radiologists read the data for the presence of nodules. Sensitivity and specificity were calculated. Gold standard was either histology or long-term follow-up. Contrast-to-Noise-Ratio (CNR) was measured for all detected lesions in all MRI sequences. RESULTS Average maximum diameter of the lesions was 15 mm. Overall sensitivity and specificity of MRI were 48% (26/54) and 88% (29/33) compared to low-dose CT. Sensitivity of MRI was significantly higher for malignant nodules (78% (12.5/16)) than for benign ones (36% (13.5/38); P=0.007). There was no statistically significant difference in sensitivity between nodules (benign and malignant) larger or smaller than 10 mm (P=0.7). Inter observer agreement was 84% (κ=0.65). Lesion-to-background CNR of T2-weighted single-shot turbo-spin-echo was significantly higher for malignant nodules (89±27) than for benign ones (56±23; P=0.002). CONCLUSION The sensitivity of MRI for detection of malignant pulmonary nodules in a high-risk population is 78%. Due to its inherent soft tissue contrast, MRI is more sensitive to malignant nodules than to benign ones. MRI may therefore represent a useful test for early detection of lung cancer.

Magnetic resonance angiography in extracranial giant cell arteritis.

Background:Noninvasive diagnosis of giant cell arteritis (GCA) remains challenging, particularly with regard to evaluation of extracranial arterial disease. Objectives:The objective of the study was to retrospectively review extracranial involvement in patients with GCA and/or polymyalgia rheumatica (PMR), evaluated with magnetic resonance imaging (MRI), especially 3-dimensional contrast-enhanced magnetic resonance angiography images of the aortic arch and its branches. Methods:Clinical information, biopsy status, and MRI examinations of 28 patients with GCA/PMR were reviewed. Patient images were mixed randomly with 20 normal control images and were independently reviewed by 2 radiologists. Interobserver agreement for detection of arterial stenosis was determined by the k coefficient. Results:Both readers described vascular alterations in keeping with extracranial GCA in 19 of 28 patients (67%) with good interobserver agreement (k = 0.73) and with even higher agreement on diagnosing nonocclusive versus occlusive disease (k = 1.00). The most common lesions were bilateral axillary stenosis or obstructions, observed by both readers in 8 patients (28%). Among the 19 patients with magnetic resonance angiography lesions in the subclavian/axillary arteries, 12 (75%) had biopsy-proven GCA, but only 5 (41%) of these patients had clinical features of large artery disease. Conclusions:In our series review, MRI could provide accurate information on involvement of the aortic arch and its branches in extracranial GCA, depicting different degrees of stenosis. Our analysis also illustrates that occult large artery vasculitis should be considered in patients without biopsy-proven GCA, patients with classic GCA but without clinical signs of large artery disease, and in patients initially diagnosed as having PMR.

Quantitative Magnetic Resonance Imaging Evaluation of the Olfactory System in Kallmann Syndrome: Correlation with a Clinical Smell Test

Objectives: To measure olfactory bulbs and sulci using dedicated magnetic resonance imaging (MRI) sequences and specific measurement tools in Kallmann syndrome (KS) patients with a well-established genotype and phenotype, as well as correlate MRI findings with a clinical smell test. Methods: MRI was performed in 21 patients with KS and 16 healthy volunteers; olfactory dysfunction was assessed using the Smell Identification Test (UPSIT), a qualitative suprathreshold olfaction test. Coronal turbo spin echo T2-weighted and volumetric T1-weighted gradient echo sequences were acquired in a 1.5T system. ImageJ software was used to obtain olfactory bulb volumes and olfactory sulcus depths and lengths. Data were analyzed with SPSS 15.0 and the Kappa index was used to evaluate the agreement between the UPSIT and MRI. Results: The UPSIT showed 14 patients with anosmia and 6 with moderate hyposmia. Eighteen patients (85%) presented altered rhinencephalon structures in the MRI. Sixteen patients (76%) presented olfactory bulb aplasia (14/16 bilaterally), and these patients presented a total of 16 aplastic sulci. There was moderate agreement between the MRI quantitative evaluation and the UPSIT (overall Kappa = 0.55), but when considering the presence of aplastic bulbs and anosmia, we found almost perfect agreement (Kappa = 0.87). Three patients had normal rhinencephalon structures, including one with a KAL1 gene mutation. Conclusion: Olfactory bulb and sulcus aplasia were the most common findings in KS patients. We objectively demonstrated agreement between MRI findings and the smell test, especially the presence of bulb aplasia and anosmia. Therefore, our findings help ascertain MRI accuracy in the diagnosis of KS, differentiating patients with hypogonadotropic hypogonadism with an apparently normal or difficult to evaluate sense of smell.

Clinical assessment and molecular analysis of GnRHR and KAL1 genes in males with idiopathic hypogonadotrophic hypogonadism

Objective  The pathogenesis of idiopathic hypogonadotrophic hypogonadism (IHH) is mostly unclear. We characterized the clinical findings and molecular analysis of GnRHR and KAL1 genes in 26 Brazilian males with IHH with and without hyposmia/anosmia.

Non-contrast-enhanced preoperative assessment of lung perfusion in patients with non-small-cell lung cancer using Fourier decomposition magnetic resonance imaging

OBJECTIVE To investigate non-contrast-enhanced Fourier decomposition MRI (FD MRI) for assessment of regional lung perfusion in patients with Non-Small-Cell Lung Cancer (NSCLC) in comparison to dynamic contrast-enhanced MRI (DCE MRI). METHODS Time-resolved non-contrast-enhanced images of the lungs were acquired prospectively in 15 patients using a 2D balanced steady-state free precession (b-SSFP) sequence. After non-rigid registration of the native image data, perfusion-weighted images were calculated by separating periodic changes of lung proton density at the cardiac frequency using FD. DCE MRI subtraction datasets were acquired as standard of reference. Both datasets were analyzed visually for perfusion defects. Then segmentation analyses were performed to describe perfusion of pulmonary lobes semi-quantitatively as percentages of total lung perfusion. Overall FD MRI perfusion signal was compared to velocity-encoded flow measurements in the pulmonary trunk as an additional fully quantitative reference. RESULTS Image quality ratings of FD MRI were significantly inferior to those of DCE MRI (P<0.0001). Sensitivity, specificity, and accuracy of FD MRI for visual detection of perfusion defects were 84%, 92%, and 91%. Semi-quantitative evaluation of lobar perfusion provided high agreement between FD MRI and DCE MRI for both entire lungs and upper lobes, but less agreement in the lower parts of both lungs. FD perfusion signal showed high linear correlation with pulmonary arterial blood flow. CONCLUSION FD MRI is a promising technique that allows for assessing regional lung perfusion in NSCLC patients without contrast media or ionizing radiation. However, for being applied in clinical routine, image quality and robustness of the technique need to be further improved.

Complicações do uso intravenoso de agentes de contraste à base de gadolínio para ressonância magnética

Os agentes de contraste a base de gadolinio sao muito mais seguros que o contraste iodado, no entanto, existem complicacoes que devem ser reconhecidas, para orientacao e tratamento adequados. A incidencia total de reacoes adversas aos meios de contraste em ressonância magnetica varia entre 2% e 4%. Casos de reacoes adversas agudas maiores ao gadolinio, como laringoespasmo e choque anafilatico, sao raros. As complicacoes cronicas com o uso do gadolinio tambem existem e, recentemente, foi descrita associacao entre seu uso e uma doenca dermatologica rara que ocorre em pacientes com insuficiencia renal. A fibrose nefrogenica sistemica foi tema de anuncio publico oficial pela agencia americana de regulacao de drogas, a Food and Drug Administration. Esta doenca progressiva caracteriza-se pelo espessamento e endurecimento da pele e fibrose, que podem acometer outras partes do corpo. Os pacientes que desenvolveram esta complicacao apresentavam insuficiencia renal cronica, estavam em acidose metabolica e foram submetidos a angiografia por ressonância magnetica, provavelmente com injecao de grande volume de contraste paramagnetico. Esta revisao tem o objetivo de apresentar uma descricao sucinta dos tipos de meios de contraste a base de gadolinio, possiveis complicacoes e medidas para prevencao e tratamento destas.Gadolinium-based contrast agents are much safer than the iodinated ones; however complications may occur and should be recognized for appropriate orientation and management. The total incidence of adverse reactions to contrast agents in magnetic resonance imaging ranges between 2% and 4%. Cases of severe acute reactions to gadolinium, such as laryngospasm and anaphylactic shock, are rare. Chronic complications secondary to the use of gadolinium also can occur and, recently an association between its use and a rare dermatologic disease occurring in patients with renal failure has been reported. Nephrogenic systemic fibrosis was the subject of an official health notification issued by the American Food and Drug Administration. This progressive disease is characterized by hardened skin with fibrotic nodules and plaques which may involve other parts of the body. Patients who have been affected by this disorder presented chronic renal failure, with metabolic acidosis and had been submitted to magnetic resonance angiography, probably involving exposure to large amounts of intravenous paramagnetic contrast. This review is aimed at presenting a succinct description of the gadolinium-based contrast agent types, possible secondary complications, their preventive measures and management.

Variation of densitometry on computed tomography in COPD--influence of different software tools.

Objectives Quantitative multidetector computed tomography (MDCT) as a potential biomarker is increasingly used for severity assessment of emphysema in chronic obstructive pulmonary disease (COPD). Aim of this study was to evaluate the user-independent measurement variability between five different fully-automatic densitometry software tools. Material and Methods MDCT and full-body plethysmography incl. forced expiratory volume in 1s and total lung capacity were available for 49 patients with advanced COPD (age = 64±9 years, forced expiratory volume in 1s = 31±6% predicted). Measurement variation regarding lung volume, emphysema volume, emphysema index, and mean lung density was evaluated for two scientific and three commercially available lung densitometry software tools designed to analyze MDCT from different scanner types. Results One scientific tool and one commercial tool failed to process most or all datasets, respectively, and were excluded. One scientific and another commercial tool analyzed 49, the remaining commercial tool 30 datasets. Lung volume, emphysema volume, emphysema index and mean lung density were significantly different amongst these three tools (p<0.001). Limits of agreement for lung volume were [−0.195, −0.052l], [−0.305, −0.131l], and [−0.123, −0.052l] with correlation coefficients of r = 1.00 each. Limits of agreement for emphysema index were [−6.2, 2.9%], [−27.0, 16.9%], and [−25.5, 18.8%], with r = 0.79 to 0.98. Correlation of lung volume with total lung capacity was good to excellent (r = 0.77 to 0.91, p<0.001), but segmented lung volume (6.7±1.3 – 6.8±1.3l) were significantly lower than total lung capacity (7.7±1.7l, p<0.001). Conclusions Technical incompatibilities hindered evaluation of two of five tools. The remaining three showed significant measurement variation for emphysema, hampering quantitative MDCT as a biomarker in COPD. Follow-up studies should currently use identical software, and standardization efforts should encompass software as well.

Valvas endobrônquicas em pacientes com enfisema grave: avaliação por TC da completude das fissuras pulmonares, resposta radiológica ao tratamento e análise quantitativa do enfisema

OBJECTIVE: To evaluate lung fissures completeness, post-treatment radiological response and quantitative CT analysis (QCTA) in a population of severe emphysematous patients submitted to endobronchial valves (EBV) implantation. MATERIALS AND METHODS: Multi-detectors CT exams of 29 patients were studied, using thin-section low dose protocol without contrast. Two radiologists retrospectively reviewed all images in consensus; fissures completeness was estimated in 5% increments and post-EBV radiological response (target lobe atelectasis/volume loss) was evaluated. QCTA was performed in pre and post-treatment scans using a fully automated software. RESULTS: CT response was present in 16/29 patients. In the negative CT response group, all 13 patients presented incomplete fissures, and mean oblique fissures completeness was 72.8%, against 88.3% in the other group. QCTA most significant results showed a reduced post-treatment total lung volume (LV) (mean 542 ml), reduced EBV-submitted LV (700 ml) and reduced emphysema volume (331.4 ml) in the positive response group, which also showed improved functional tests. CONCLUSION: EBV benefit is most likely in patients who have complete interlobar fissures and develop lobar atelectasis. In patients with no radiological response we observed a higher prevalence of incomplete fissures and a greater degree of incompleteness. The fully automated QCTA detected the post-treatment alterations, especially in the treated lung analysis.

Role of MRI for detection and characterization of pulmonary nodules

ZusammenfassungHintergrundMit den technischen Weiterentwicklungen in den vergangenen Jahren hat sich die MRT zu einem methodisch ausgereiften und für spezifische pulmonale Fragestellungen bereits auch klinisch bewährten Untersuchungsverfahren entwickelt. Ohne Strahlenexposition kombiniert sie morphologische und funktionelle Diagnostik und ergänzt das Spektrum der etablierten Verfahren für die bildgebende Diagnostik der Lunge.Ziel der Arbeit und MethodenDiese Arbeit gibt einen Überblick über die aktuell verwendeten Sequenzen und Techniken zur Darstellung pulmonaler Rundherde und analysiert deren klinischen Stellenwert anhand der aktuellen Studienlage. In Zentrum stehen dabei die Detektion pulmonaler Metastasen, die Detektion primär pulmonaler Malignome bei Personen mit Risikoprofil und die Abklärung pulmonaler Rundherde hinsichtlich ihrer Dignität.Ergebnisse und DiskussionDie MRT besitzt im Vergleich zum Referenzstandard Niedrigdosis-CT eine Sensitivität von ca. 80 % für die Detektion maligner pulmonaler Rundherde und ist der CT damit etwas unterlegen. Vorteile der MRT gegenüber der Niedrigdosis-CT sind andererseits die höhere Spezifität bei der Differenzierung maligner und benigner pulmonaler Rundherde sowie die fehlende Strahlenexposition. Außerhalb von Studien kann ein breiter Einsatz der MRT als Screeningverfahren zur Detektion und Abklärung pulmonaler Rundherde aufgrund der noch ungenügenden Datenlage derzeit noch nicht empfohlen werden. Das diagnostische Potenzial der MRT für die Früherkennung und das Staging pulmonaler Malignome rechtfertigt aber die weitere Evaluation der MRT als sekundäre Modalität im Rahmen von Studien.AbstractBackgroundDue to physical and technical limitations, magnetic resonance imaging (MRI) has hitherto played only a minor role in image-based diagnostics of the lungs. However, as a consequence of important methodological developments during recent years, MRI has developed into a technically mature and clinically well-proven method for specific pulmonary questions.Objectives and methodsThe purpose of this article is to provide an overview on the currently available sequences and techniques for assessment of pulmonary nodules and analyzes the clinical significance according to the current literature. The main focus is on the detection of lung metastases, the detection of primary pulmonary malignancies in high-risk individuals and the differentiation between pulmonary nodules of benign and malignant character.Results and conclusionThe MRI technique has a sensitivity of approximately 80 % for detection of malignant pulmonary nodules compared to the reference standard low-dose computed tomography (CT) and is thus somewhat inferior to CT. Advantages of MRI on the other hand are a higher specificity in differentiating malignant and benign pulmonary nodules and the absence of ionizing radiation exposure. A systematic use of MRI as a primary tool for detection and characterization of pulmonary nodules is currently not recommended due to insufficient data. The diagnostic potential of MRI for early detection and staging of malignant pulmonary diseases, however, seems promising. Therefore, further evaluation of MRI as a secondary imaging modality in clinical trials is highly warranted.BACKGROUND Due to physical and technical limitations, magnetic resonance imaging (MRI) has hitherto played only a minor role in image-based diagnostics of the lungs. However, as a consequence of important methodological developments during recent years, MRI has developed into a technically mature and clinically well-proven method for specific pulmonary questions. OBJECTIVES AND METHODS The purpose of this article is to provide an overview on the currently available sequences and techniques for assessment of pulmonary nodules and analyzes the clinical significance according to the current literature. The main focus is on the detection of lung metastases, the detection of primary pulmonary malignancies in high-risk individuals and the differentiation between pulmonary nodules of benign and malignant character. RESULTS AND CONCLUSION The MRI technique has a sensitivity of approximately 80 % for detection of malignant pulmonary nodules compared to the reference standard low-dose computed tomography (CT) and is thus somewhat inferior to CT. Advantages of MRI on the other hand are a higher specificity in differentiating malignant and benign pulmonary nodules and the absence of ionizing radiation exposure. A systematic use of MRI as a primary tool for detection and characterization of pulmonary nodules is currently not recommended due to insufficient data. The diagnostic potential of MRI for early detection and staging of malignant pulmonary diseases, however, seems promising. Therefore, further evaluation of MRI as a secondary imaging modality in clinical trials is highly warranted.

Kallmann syndrome and mirror movements: White matter quantitative evaluation with magnetic resonance imaging

Kallmann syndrome (KS), characterized by the association of hypogonadotropic hypogonadism and anosmia, may present many other phenotypic abnormalities, including neurologic features as involuntary movements, called mirror movements (MM). MM etiology probably involves a complex mechanism comprising corticospinal tract abnormal development associated with deficient contralateral motor cortex inhibitory system. In this study, in order to address previous hypotheses concerning MM etiology, we identified and quantified white matter (WM) alterations in 21 KS patients, comparing subjects with and without MM and 16 control subjects, using magnetization transfer ratio (MTR) and T2 relaxometry (R2). Magnetization transfer and T2 double-echo images were acquired in a 1.5 T system. MTR and R2 were calculated pixel by pixel to initially create individual maps, and then, group average maps, co-registered with MNI305 stereotaxic coordinate system. After analysis of selected regions of interest, we demonstrated areas with higher T2 relaxation time and lower MTR values in KS patients, with and without MM, differently involving corticospinal tract projection, frontal lobes and corpus callosum. Higher MTR was observed only in pyramidal decussation when compared in both groups of patients with controls. In conclusion, we demonstrated that patients with KS have altered WM areas, presenting in a different manner in patients with and without MM. These data suggest axonal loss or disorganization involving abnormal pyramidal tracts and other associative/connective areas, relating to the presence or absence of MM. We also found a different pattern of alteration in pyramidal decussation, which can represent the primary area of neuronal disarrangement.