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A case of a patient with the diagnosis of a neoformation of the blind intestine is discussed. On CT for staging an image at the level of the intrapancreatic tract of main bile duct of not certain interpretation was visualized. On US choledocholithiasis shown by the typical appearance of a hyperechoic image with posterior shadowing was diagnosed. In the study case US was shown to be the procedure of first choice.

The case of a 40-year-old male patient come to the emergency service with symptoms suspicious of biliary colic, is presented. Liver sonography was requested to evaluate the parenchyma, the gallbladder and bile duct caliber in the suspicion of lithiasis. During the examination a hyper-reflecting image with posterior shadowing was detected at the level of the gallbladder infundibulum. However, the shadowing was not typical of lithiasis. This aroused some doubts and the scan was repeated after some minutes: an absolutely normal infundibulum was visualized. The shadowing was therefore an artifact probably due to a partial volume effect of the air contained in the distended duodenum, in contact with the gallbladder. The formation process of the sonographic image is carefully analyzed with particular reference to the situations generating artifacts.

Primary megaureter is visualized as a typical dilatation on urography. Adequate oblique projections should be added to depict the juxtavesical tract of normal caliber. In even the most severe forms pyelocaliectasis is absent or mild and the ureter is not tortuous. Sonography as well as fluoroscopy during urography shows hyperperistalsis in the dilated tract and aperistalsis in the juxtavesical tract. Cystography rules out vesicoureteral reflux. In prune-belly syndrome the megaureter is bilateral and massive with no evidence of obstructions. The sonographic finding of hydronephrosis or hydroureteronephrosis and the absence of vesicoureteral reflux on voiding cystography lead to the suspicion of ureteral valves, directly documented on urography as sharp and transverse filling defects. Retrograde pyelography can better define the obstructing area and documents the normality of the underlying tract. With this procedure, the valvular flaps appear with a superior convexity (like a small umbrella). MR-urography still to be validated clinically, will be able to provide novel perspectives.

Problems concerning the use of different imaging modalities in N staging of the neck are dealt with. The peculiar features, findings, sensitivity, specificity and diagnostic accuracy of each modality in the diagnosis of nature of cervical lymphadenopathy are described, as reported in most recent reports of literature, and according to the personal experience. CT/MRI criteria commonly used to establish whether a lymph node is metastatic or benign/reactive are related to the size, morphology, density (CT), signal intensity (MRI), evidence of central necrosis and extracapsular spread. Color Doppler US is a reliable method in the diagnosis of cervical metastatic lymphadenopathy even if no parameter is highly predictive; the combination of different findings, especially cortical thickening and structural inhomogeneity with thin, compressed, displaced or non visualized hilum makes the procedure significantly sensitive and specific. Intranodal hilar vascularization on color Doppler, with high resistance arterial flow (PI > 1.5), enhances the predictive value of findings of bi-dimensional sonography. Extracapsular spread impacts on survival as well as on the number of recurrences, which increases in patients with extracapsular spread; the disease-free interval is less in these patients. The identification and definition of extracapsular spread is based on some CT/MRI criteria as: 1) lymph nodes with spiky, irregular margins; 2) loss of adipose cleavage planes around the node and thickening of adjacent fascia; 3) apparent invasion of an adjacent structures or muscles. Similarly to CT/MR, sonographic findings of extracapsular spread can be: 1) blurred margins and irregular contours; 2) invasion of an adjacent structure or muscle.

Medullary thyroid carcinoma is the least frequent thyroid neoplasm; it originates in thyroid parafollicular cells (calcitonin secreting C cells). In 80% of cases it is sporadic, in the remaining 20% it is familial, associated or not to other endocrinopathies as pheochromocytoma and hyperparathyroidism (MEN 2A, MEN 2B, and isolated familial medullary thyroid carcinoma). Preclinical diagnosis in relatives of affected subjects (preferably at pediatric age) is essential for successful therapy and is performed with genetic and biochemical screening tests. The genetic screening is based on DNA analysis (RET proto-oncogene mutations) of the patient, and if positive of all first degree relatives, to separate sporadic (somatic mutations) from familial (germline mutations) forms. The biochemical screening is based on calcitonin determination and its increase after pentagastrin stimulation, (a peculiar characteristic of medullary thyroid carcinoma, the first biochemical disorder in a subject at risk) and is mainly used in genetically silent familial medullary thyroid carcinoma. The principal negative prognostic factors of medullar thyroid carcinoma and the debate concerning the use of calcitonin determination in the diagnosis of the "cold" thyroid nodule have been analyzed.

The role of diagnostic imaging in differentiated thyroid carcinoma is analyzed. 99mTc-pertechnetate 123I and 131I scintigraphy allows the evaluation of nodules with their differentiation in cold (hypofunctioning) and hot (functionally autonomous) nodules; thyroid carcinomas are cold nodules even if most of them are benign. On sonography thyroid nodules are well visualized with the definition of their site, number, size (not very useful parameters for the diagnosis of malignancy), echoic structure, and vascularization on color Doppler. The sonographic findings suggestive of differentiated thyroid carcinoma are: solid and hypoechoic structure, irregular ill-defined margins, absent or discontinuous peripheral ring, microcalcification, intranodular vascularization, local lymphadenopathies. These findings are characteristic but not pathognomonic, mostly for papillary carcinoma, while in the frequently isoechoic follicular carcinoma microcalcification and lymph node metastases are rare. Only the finding, although rather infrequent, of the dissemination to adjacent structures (muscles and vessels) is a definite indication for malignancy of a thyroid nodule. Color Doppler sonography plays a major role in the postoperative staging and follow-up, in combination with thyroglobulin determination and 131I whole body scintigraphy and it allows the detection of local and/or laterocervical lymph node recurrence. The most typical sonographic findings of metastatic lymphadenopathy are the roundish shape (length/anteroposterior diameter ratio-L/A < 1.5), not visible or displaced nodal hilum, thickened cortical layer with echoic structure similar to that of thyroid parenchyma, at times with microcalcification, cortical vascularization and dismantled angioarchitecture. CT and MRI are occasionally more useful to evaluate the substernal or retrosternal extension of voluminous thyroid masses and to identify local or distant metastases.

In thyrotoxicosis, imaging mainly scintigraphy, color Doppler sonography and radioiodine uptake test are used in the differential diagnosis as well as in the morphofunctional evaluation of the thyroid before and after therapy (mainly pharmacological or with radioiodine). Radioiodine uptake test differentiates high uptake thyrotoxicosis (Graves'disease, toxic nodular goiter) and low uptake thyrotoxycosis (subacute or silent thyroiditis, ectopic thyrotoxicosis, iodine-induced hyperthyroidism). In Graves'disease scintigraphy shows thyroid enlargement with intense homogeneous tracer uptake; rarely nodules with no uptake are present. On color Doppler sonography, a part from enlargement, typical findings are: diffuse structural hypoechogenicity (at times with echoic nodules), parenchymal hypervascularization ("thyroid inferno"), high systolic velocities (PSV > 70-100 cm/sec) in inferior thyroid arteries. Scintigraphy is the only method able to evidence an autonomously functioning thyroid nodule and stage it (in association to clinical findings and TSH, FT3, FT4 determination) as: toxic, non toxic (or pretoxic) and compensated, depending on whether there is inhibition of extranodular tissue. A scintigraphically "hot" nodule appears hypervascularized on color Doppler sonography (especially in the toxic or pre-toxic phase) with high PSV (> 50-70 cm/sec) in the ipsilateral inferior thyroid artery. The most reliable parameters in the evaluation of the therapeutic efficacy are: decreases in thyroid (Graves'disease) or nodular (autonomously functioning nodule) volume; decreased radioiodine uptake (Graves'disease); functional recovery of suppressed parenchyma (autonomously functioning nodule); decreased PSV in the inferior thyroid arteries.

In diffuse or nodular euthyroid goiter, diagnostic imaging is indicated to define, by sonography, the morphology, size and structure of the goiter and to evaluate, by scintigraphy, the regional thyroid function. The instrumental diagnosis of thyroid nodule is essentially based on sonography, scintigraphy and (US-guided) needle aspiration cytology. The evaluation of some sonographic findings (echogenicity, calcification, lesion margins and presence of peripheral ring) may direct to the differentiation of a benign or malignant lesion. The role of color Doppler in the characterization of thyroid nodules is still controversial. Scintigraphy provides information on nodular function, being also the only exam able to show the presence of autonomously functioning thyroid tissue ("hot" nodule), whose diagnosis allows to rule out the presence of thyroid carcinoma with a very strong probability. In intrathoracic goiter, CT and MRI and indicated to show the continuity with the cervical thyroid and to define the relationships with adjacent structures. Radioiodine scintigraphy shows with high (> 90%) diagnostic accuracy the thyroid nature of a mediastinal mass (plunging goiter).

The role of preoperative noninvasive diagnostic procedures in the management of benign thyroid diseases is critically reviewed and on the basis of a series of more than 13,000 thyroid nodules, sequentially examined, the role of preoperative fine needle aspiration (FNA) cytology in discriminating benign from malignant lesions, is assessed. Retrospective studies were performed to determine the diagnostic accuracy of FNA adopted as routine preoperative screening procedure as compared to intraoperative frozen section (FS) analysis. US-guided FNA was shown to be more accurate allowing the preoperative identification of occult or minimal carcinoma: in fact about 3% of malignant thyroid nodules were detected. Moreover, the operation time is reduced, and unnecessary surgical treatments for benign lesions are eliminated, preventing the need of two-stage cancer surgery. FNA is a cost-effective diagnostic tool with about 20% reduction in the cost of care of patients with thyroid nodules. Most recent methods of molecular biology which seem promising in thyroid tissue sampled by FNA to detect malignant lesions missed by conventional cytology and included in the generic category of "follicular proliferation", are analyzed.

The diagnostic imaging of the thyroid is based on sonography and scintigraphy, which to-date play a unique role in the morphofunctional study of the thyroid gland. The high spatial resolution of sonography allows an accurate evaluation of the thyroid morphology, size and parenchymal structure. Color Doppler sonography allows a qualitative assessment associated with quantitative parameters of glandular vascularization. Furthermore, sonography is the simplest procedure to achieve an accurate, reproducible measurement of thyroid volume. Scintigraphy provides information unavailable by other methods on the regional thyroid function. The most common tracer for thyroid scintigraphy is 99mTc pertechnetate. 123I and 131I are essential for radioiodine uptake test. CT and MRI, while invaluable for other organs and apparatus, play a limited role in the diagnosis of thyroid disease.

Since it serves as the site for the implantation of the fertilized ovum, it is evident that significant disorders in the uterine cavity and endometrial mucosa represent potential factors of sterility/infertility. Among the acquired pathological conditions, a possible cause of sterility, there are inflammatory (endometritis) or post-traumatic (synechiae) disorders and proliferative mucosal (endometrial hyperplasia, polyps) and muscular (fibroma) disorders. Sonography (by transabdominal or preferably endovaginal route, and sonohysterography) is the first choice procedure being in most cases adequate for clinical assessment. According to the specific disease, the diagnostic combination with hysteroscopy, hysterosalpingography, Magnetic Resonance Imaging can be suitable.

The diseases of the ovary which most frequently cause infertility are: anovulation from follicular atresia, the empty follicle syndrome, the luteinized unruptured follicle syndrome; chronic anovulation syndromes, within which polycystic ovarian syndrome plays a major role; ovarian endometriosis. Sonography and Color Doppler US are the first choice procedures in the monitoring of ovarian cycles, which combined with serum hormone values, are able to identify possible changes in the physiologic sequence of the cycle. In follicular atresia, ovaries with minute follicles (3mm or less) and early disappearance of primary follicle are observed on sonography. The empty follicle syndrome characterized by the lack of oocytes within the primary follicle, is of difficult sonographic diagnosis, a possible sign being the missed visualization of cumulus oophorus. The luteinized unruptured follicle syndrome consists in the absence of oocyte expulsion from primary follicle persisting more than 48 hours after LH blood peak. Doppler spectra of blood flow in perifollicular ovarian arteries maintain the features of the follicular phase, i.e. low diastolic velocities and high resistances. Among chronic anovulation syndromes, hyper-and hypogonadotropism cause ovarian amenorrhea where ovaries are similar to those of women in menopause: small size, very few or absent follicles. The polycystic ovarian syndrome is characterized by an abnormal pulsatile GnRH release which causes LH hypersecretion and FSH hyposecretion. The latter is not able to stimulate the growth and maturation of follicles, while the former causes hyperandrogenism with hirsutism and obesity and is responsible for hypertrophy and stromal hyperechogenicity. The sonographic diagnosis of polycystic ovarian syndrome is based on standardized morphostructural signs as increased volume of the ovaries (> 10 cm3), the presence of numerous (> or = 10) peripheral microfollicles (< or = 5 mm) with hyperechoic stroma. The endometrial cyst, usually present in ovarian endometriosis is visualized with sonography as a round neoformation with ill-defined walls, filled with a uniformly hypoechoic, corpuscular, partly hemorrhagic fluid; less frequently the appearance is that of a more complex structure posing differential diagnostic problems, mainly with the hemorrhagic corpus luteum; both pathological conditions appear poorly vascularized at Color Doppler, with tracings of high resistance arterial flow. Among the procedures of second choice, CT can show the high blood density common to the two conditions while on MRI the signal is mostly hyperintense in T1-weighted sequences with areas of lower signal intensity in T2-weighted sequences.

The mechanisms of the spread to the kidney and urinary tract of miliary tuberculosis which involves the urinary system with a rather high incidence, and, if not detected, may result in a functionless kidney for the often nonspecific symptomatology, are analyzed. These considerations account for the seriousness of the problem of urinary tuberculosis, whose great topical interest is unfortunately proven not only in the African continent where it is particularly common, but also in Europe. The lesions underlying the damage to the renal parenchyma and lower urinary tract are carefully examined for a correct interpretation of the radiologic signs. Most representative patterns of the various stages of urinary tuberculosis are described; the attention is focused on conventional radiology, still the most suitable imaging procedure for its early identification. The role of the other procedures which even if are not of first choice when urinary tuberculosis is suspected, in some cases may be useful in the approach to the disease. The mechanisms of the spread of genital tract tuberculosis, less frequent than urinary tuberculosis, but seemingly interesting for its clinical and diagnostic features, are considered. An accurate analysis of major patterns of tuberculosis of male and female genital tract is reported to better understand the various aspects of diagnostic imaging.