Evaluation of substernal goiters using computed tomography and MR imaging

Lessons learnt from the global iodinated contrast media shortage in head and neck imaging

A recent shortage in the global supply of iodinated contrast media (ICM) has required health service providers to review their contrast administration policies and implement strategies to conserve inventory. This article will review the current best practices in head and neck imaging for a variety of common presentations and provide examples where alternative imaging can be considered due to the recent ICM shortage. Ultrasound and MRI techniques can feature heavily in many diagnostic processes in head and neck pathology, and a variety of common presentations can be appropriately investigated through clinical evaluation or naso-endoscopy. In many instances, for the routine assessment of non-acute adult and paediatric head and neck presentations, the use of contrast-enhanced CT can be safely minimised to conserve ICM if required.

Assessment and management of cervico-mediastinal goiter

Cervico-mediastinal goiter is a particular entity from the point of view of thyroid surgery. Its volume, hardness and intrathoracic extension require the surgeon to adapt technique and perform a painstaking preoperative work-up, so as to draw up fully-fledged plan. CT is now indispensable, to anticipate risks and determine whether sternotomy is needed. Surgery seems to induce more postoperative complications than in conventional surgery, although they can be reduced by retrograde dissection of the inferior laryngeal nerve and downward dissection of the posterior side of the lobe to optimize control of adjacent structures. This surgery requires optimal teamwork between all of the specialties involved in patient management: medical, radiological, anesthesiological and surgical.

Thyroid nodules and differentiated thyroid cancer: update on the Brazilian consensus

Thyroid nodules are frequent findings, especially when sensitive imaging methods are used. Although thyroid cancer is relatively rare, its incidence is increasing, particularly in terms of small tumors, which have an uncertain clinical relevance. Most patients with differentiated thyroid cancer exhibit satisfactory clinical outcomes when treatment is appropriate, and their mortality rate is similar to that of the overall population. However, relapse occurs in a considerable fraction of these patients, and some patients stop responding to conventional treatment and eventually die from their disease. Therefore, the challenge is how to identify the individuals who require more aggressive disease management while sparing the majority of patients from unnecessary treatments and procedures. We have updated the Brazilian Consensus that was published in 2007, emphasizing the diagnostic and therapeutic advances that the participants, representing several Brazilian university centers, consider most relevant in clinical practice. The formulation of the present guidelines was based on the participants' experience and a review of the relevant literature.

Prevalence of upper airway obstruction in patients with apparently asymptomatic euthyroid multi nodular goitre

AIMS

To study the prevalence of upper airway obstruction (UAO) in "apparently asymptomatic" patients with euthyroid multinodular goitre (MNG) and find correlation between clinical features, UAO on pulmonary function test (PFT) and tracheal narrowing on computerised tomography (CT).

MATERIALS AND METHODS

Consecutive patients with apparently asymptomatic euthyroid MNG attending thyroid clinic in a tertiary centre underwent clinical examination to elicit features of UAO, PFT, and CT of neck and chest.

STATISTICAL ANALYSIS USED

Statistical analysis was done with SPSS version 11.5 using paired t-test, Chi square test, and Fisher's exact test. P value of <0.05 was considered to be significant.

RESULTS

Fifty-six patients (52 females and four males) were studied. The prevalence of UAO (PFT) and significant tracheal narrowing (CT) was 14.3%. and 9.3%, respectively. Clinical features failed to predict UAO or significant tracheal narrowing. Tracheal narrowing (CT) did not correlate with UAO (PFT). Volume of goitre significantly correlated with degree of tracheal narrowing.

CONCLUSIONS

Clinical features do not predict UAO on PFT or tracheal narrowing on CT in apparently asymptomatic patients with euthyroid MNG.

Morbidity and mortality of thyroidectomy for substernal goiter

BACKGROUND

Our objective was to evaluate morbidity and mortality of thyroidectomy in substernal goiters and identify patients at risk for these events.

METHODS

The medical records of 127 patients with substernal goiters were retrospectively reviewed.

RESULTS

The most common preoperative symptom was shortness of breath (48%). 13% of the 127 patients were asymptomatic. Preoperative imaging identified tracheal deviation in 69% and tracheal compression in 41% of the cases. Substernal goiters were resected via a cervical approach in 100% of the cases. Six patients (5%) had postoperative hoarseness, 1 had permanent vocal cord paralysis, and 19 (15%) had transient postoperative hypocalcemia. The mortality and permanent hypoparathyroidism were null. Patients with postoperative complications had larger goiters and were more likely to have tracheal compression.

CONCLUSIONS

Thyroid resection via a cervical approach for substernal goiters is associated with low rate of morbidity and no mortality. Patients with large tumors and tracheal compression are more likely to develop postoperative complications.

Multidetector computed tomography in the preoperative evaluation of retrosternal goiters: a useful procedure for patients for whom magnetic resonance imaging is contraindicated

BACKGROUND

Diagnostic imaging provides useful anatomical and morphological information of cervico-mediastinal goiters. The aim of this study was to assess the usefulness of multidetector computed tomography (MDCT) with multiplanar reformatting and volume rendering reconstructions for the preoperative evaluation of retrosternal goiters in patients for whom magnetic resonance imaging is contraindicated.

METHODS

From March 2006 to January 2009, 34 patients (20 women and 14 men; mean age, 48 years; range, 42-74 years) with suspected cervico-mediastinal goiter were assessed by MDCT after intravenous injection of contrast material. The following parameters were evaluated: morphology, size, and enhancement of thyroid lobes; presence, location, and mediastinal extension of thyroid tissue; and relations with mediastinal vessels and organs. All patients underwent thyroidectomy. A reference group of 34 patients evaluated by single-detector computed tomography was created. The two groups of patients were compared searching for operative time (OT, in hours), hospital stay (HS, in days), and morbidity rate observed after thyroid surgery in all cases.

RESULTS

In 29/34 patients, thyroid was enlarged with left mediastinal extension in 12 cases, right extension in 10 cases, and posterior extension in 7 cases. In 3/34 patients, a normal cervical thyroid connected to the mediastinal goiter through a thin parenchymal stripe was observed. In 2/34 patients, thyroid lobes were enlarged, without mediastinal extension. By comparing the two groups of patients for OT and HS values, a significant reduction to 3.7 +/- 0.1 hours and 4.3 +/- 0.1 days, respectively, was found in the group of MDCT patients, and also a trend to the reduction for morbidity rate (21%) could be recognized.

CONCLUSIONS

MDCT represents a noninvasive tool in the evaluation of retrosternal goiters. High-quality multiplanar reformatting and volume rendering reconstructions allow an optimal analysis of the plunged gland and could reduce OT, HS, and probably the morbidity rate.

Evaluation and imaging of a thyroid nodule

The approach to the thyroid nodule has been incrementally modified over the past decade. The widespread adoption of fine needle aspiration in the 1980s, coupled with increased use of serial ultrasound monitoring, arguably led to the biggest changes in recommendations for surgical intervention during the past 50 years. For the office-based practitioner, thyroid nodule presentation patterns are changing with discoveries of more thyroid "incidentalomas" and with new risk assessment challenges associated with small (<1 cm) nodules. At the same time, improved primary evaluation techniques, most notably the increasing use of small, portable ultrasound imaging units, are making many clinicians more comfortable in recommending less invasive follow-up.

Nódulos de tireóide e câncer diferenciado de tireóide: consenso brasileiro

Os nódulos tireoidianos constituem a principal manifestação clínica de uma série de doenças da tireóide com uma prevalência de aproximadamente 10% na população adulta. O maior desafio é excluir o câncer da tireóide, que ocorre em 5 a 10% dos casos. Os carcinomas diferenciados respondem por 90% dos casos de todas as neoplasias malignas da tireóide. A maioria dos pacientes com carcinoma diferenciado apresenta, geralmente, um bom prognóstico quando tratada adequadamente, com índices de mortalidade similares à população geral. No entanto, alguns indivíduos apresentam doença agressiva, desafiando o conhecimento atual e ilustrando a complexidade do manejo dessa neoplasia. No presente trabalho, reunimos 8 membros do Departamento de Tireóide da Sociedade Brasileira de Endocrinologia & Metabologia, para elaborarmos, por consenso, as diretrizes brasileiras no manejo dos nódulos tireoidianos e do câncer diferenciado da tireóide. Os membros participantes representam diferentes Centros Universitários do Brasil, refletindo diferentes abordagens diagnósticas e terapêuticas. Inicialmente, cada participante ficou responsável pela redação de determinado tema a ser enviado ao Coordenador, que, após revisão editorial e elaboração da primeira versão do manuscrito, enviou ao grupo para sugestões e aperfeiçoamentos. Quando concluído, o manuscrito foi novamente enviado e revisado por todos. A elaboração dessas diretrizes foi baseada na experiência dos participantes e revisão pertinente da literatura.

Thyroid nodules: Does the suspicion for malignancy really justify the increased thyroidectomy rates?

Thyroid nodules are frequently diagnosed today, mainly due to the wide use of neck ultrasonography (US). The majority of these are benign; suspicion for malignancy is an indication for surgery, while benign thyroid nodules may be managed conservatively. There is evidence that a large percentage of patients with thyroid nodules (many diagnosed incidentally) are over-treated. Careful and accurate identification of patients with thyroid nodules highly suspicious for underlying malignancy would allow a more reasonable therapeutic approach and would result in a reduction of the number of unnecessary thyroidectomies. Fine-needle aspiration cytology (FNAC), in conjunction with high-resolution thyroid US, are currently the most accurate and cost-effective diagnostic approach for the evaluation of patients with nodular thyroid disease. Radionuclide thyroid scanning should be used selectively. By increasing the use of FNAC, it is expected that the number of unnecessary thyroidectomies will be further diminished, thereby avoiding over-treatment, without exposing the patients to the risk of under-treatment for a highly curable cancer. However, accurate preoperative diagnosis of thyroid cancer within a thyroid nodule is not always possible and, although the problem of unnecessary surgery can further be diminished, it cannot be completely eliminated.

Doença nodular de tireóide

A tireóide normal é uma estrutura homogênea na qual, com muita freqüência, observamos a formação de nódulos. Nódulos maiores que 1,0cm costumam ser detectados clinicamente pela palpação. Um exame cuidadoso pode demonstrar a presença de nódulos em, pelo menos, 4% da população. A etiologia da doença nodular de tireóide é multifatorial, compreendendo um espectro que vai do pequeno nódulo achado de forma incidental a um grande bócio multinodular intra-torácico. Os principais aspectos com relação à avaliação diagnóstica estão relacionados à caracterização funcional e morfológica através do TSH sérico e algum tipo de imagem. Para afastar a malignidade, cuja incidência é praticamente a mesma em pacientes com nódulo solitário ou bócio multinodular (BMN), a punção aspirativa com agulha fina (PAAF) é o método de escolha. O nódulo único benigno de tireóide, frio ou quente à cintilografia, pode ser tratado com injeção percutânea de etanol ou cirurgia. O tratamento do BMN pode ser cirúrgico ou com radioiodo, se a captação de 131I for adequada. É provável que a introdução do TSH recombinante humano possa influenciar de forma importante o tratamento com 131I do BMN. O nódulo quente pode, ainda, ser tratado com 131I ou cirurgia. O tratamento supressivo com levotiroxina não é indicado no tratamento do nódulo benigno de tireóide.

Imaging of the mediastinum: applications for thoracic surgery

The diagnostic approach to patients who have mediastinal masses should include thorough preoperative imaging. Once limited to plain radiographic techniques, the radiologist now has a wide variety of imaging modalities to aid in the evaluation of the mediastinum. CT is the imaging modality of choice for evaluating a suspected mediastinal mass or a widened mediastinum, and it provides the most useful information for the diagnosis, treatment, and evaluation of postoperative complications.

Inflammatory thyroid disorders

Inflammatory thyroid disorders encompass a broad spectrum of diseases that are generally self-limited, and relatively easy to diagnose and manage. Autoimmune subtypes are by far the most commonly encountered diagnoses and create the most confusion because of simultaneous overlap and the potential for interconversion among the subtypes. The otolaryngologist will frequently see these disorders and provide valued consultative care and surgical intervention as needed.

Management of simple nodular goiter: current status and future perspectives

The simple nodular goiter, the etiology of which is multifactorial, encompasses the spectrum from the incidental asymptomatic small solitary nodule to the large intrathoracic goiter, causing pressure symptoms as well as cosmetic complaints. Its management is still the cause of considerable controversy. The mainstay in the diagnostic evaluation is related to functional and morphological characterization with serum TSH and (some kind of) imaging. Because malignancy is just as common in patients with a multinodular goiter as patients with a solitary nodule, we support the increasing use of fine-needle aspiration biopsy (cytology). Most patients need no treatment after malignancy is ruled out. In case of cosmetic or pressure symptoms, the choice in multinodular goiter stands between surgery, which is still the first choice, and radioiodine if uptake is adequate. In addition to surgery, the solitary nodule, whether hot or cold, can be treated with percutaneous ethanol injection therapy. If hot, radioiodine is the therapy of choice. Randomized studies are scarce, and the side effects of nonsurgical therapy are coming into focus. Therefore, the use of the optimum option in the individual patient cannot at present be based on evidence. However, we are of the view that levothyroxine, although widely used, should no longer be recommended routinely for this condition. Within a few years, the introduction of recombinant human TSH and laser therapy may profoundly alter the nonsurgical treatment of simple nodular goiter.

MR imaging of large multinodular goiters: observer agreement on volume versus observer disagreement on dimensions of the involved trachea

OBJECTIVE

MR imaging and sonography are considered to be among the most reliable methods available for estimating goiter volume. Our aim was to assess the observer variability of MR imaging for estimating the volume of a large multinodular goiter and the dimensions of the related trachea. Additionally, we compared the goiter volume estimates from MR imaging with those from sonography.

SUBJECTS AND METHODS

The effect of high-dose (131)I therapy on the thyroid gland and the impact on the trachea in 23 patients with a large multinodular goiter (range in volume, 100-703 mL) were monitored by observers unaware of duplicated measurements on MR imaging (n = 68) before, 1 week after, and 1 year after (131)I therapy. In goiters exclusively cervically located (n = 12), cross-sectional planimetric sonographic measurements (n = 24) were performed simultaneously with MR imaging.

RESULTS

The mean intraobserver difference for the MR imaging measurements of goiter volume was 2.1 mL (1.4%, p = 0.32), and the coefficient of variation (CV) +/- SD was 3.6% +/- 2.6%. The mean interobserver difference was 0.4 mL (0.3%, p = 0.86), and the CV +/- SD was 4.1% +/- 3.5%. Compared with MR imaging, sonography underestimated goiter volume; the mean percentage difference between the volume estimates on MR imaging and those on sonography (volume estimated on MR imaging - volume estimated on sonography) was 19.5% (95% limits of agreement: -22.2% to 83.7%), and the CV +/- SD was 15.0% +/- 12.4%. The mean interobserver difference in the MR imaging measurement of tracheal volume along the goiter extension was 7.4% (95% confidence interval: 4.0-10.8%) and that of the smallest cross-sectional area of the trachea was 7.9% (95% confidence interval: 2.9-13.2%). The corresponding CV +/- SD were 8.1% +/- 6.6% and 10.3% +/- 10.3%, respectively.

CONCLUSION

For the estimation of goiter volume, MR imaging has low intra- and interobserver variations. In contrast, the determination of tracheal dimensions using MR imaging has a high variability and, thus, is imprecise. Sonography significantly underestimates thyroid volume compared with MR imaging in patients with a large goiter.