MR pyelography in 115 patients with a dilated renal collecting system

Purpose: To evaluate the accuracy of MR pyelography in the assessment of hydroureteronephrosis.

Material and Methods: One hundred and fifteen patients, with variable degree of hydroureteronephrosis demonstrated by US and urography were subjected to MR pyelography obtained by means of two ultra-fast sequences.

Results: Of the 228 kidneys examined, the collecting systems of 130 kidneys were dilated and correctly identified on MR pyelography, with only 2 false-positive results. The specificity of MR pyelography in detecting hydronephrosis was 98%. Accuracy in revealing level of obstruction was 100%. Sensitivity in detecting stones, strictures and congenital ureteropelvic junction obstructions was respectively 68.9%, 98.5% and 100%.

Conclusion: MR pyelography can rapidly and accurately depict the morphological features of dilated urinary tracts with information regarding the degree and level of obstruction, without using contrast medium or ionizing radiation.

The Fatty Disc: An Unusual Cause of Bright Intervertebral Disc on T1-Weighted Conventional Spin-Echo MR: A Case Report

A hyperintense intervertebral disc on T1-weighted spin-echo MR image, the “bright disc”, is described in a patient with a long-standing ankylosing spondylitis.

The high signal intensity was due to the fatty infiltration of the discal tissue, as was clearly demonstrated by the comparison of MR and CT scan of the lumbar spine, probably due to progressive endochondral ossification with subsequent bone marrow metaplasia in the ossified disc.

Arteriovenous fistula of the mandible simulating an odontogenic cyst. A case report

SUMMARY

We describe a rare case of mandibular highflow arteriovenous malformation (AVM) mimicking an odontogenic cyst in a young man. The diagnosis of mandibular AVM was made by CT angiography and confirmed by digital subtraction angiography. CT scan showed the extent of mandibular bone alteration and a double enlarged mandibular canal on the same side. An AVM containing a large aneurysm was demonstrated by CT angiography.The mandibular AVM was successfully treated by endovascular therapy with Guglielmi detachable coils. On panoramic radiogram, mandibular AVMs can appear as cystic lesions without pathognomonic features. Several benign and malignant tumours of this anatomical region must be considered in the differential diagnosis.We emphasize the radiological sign of double enlarged mandibular canal and the diagnostic role of CT, particularly CT angiography, to discriminate a mandibular AVM from neoplastic entities of this region, sparing the risks of a needle biopsy.

Role of coronal oblique reconstruction as a complement to CT study of the temporal bone: normal anatomy

PURPOSE

The purpose of this study was to demonstrate the usefulness of coronal oblique multiplanar reconstruction computed tomography (MPR CT) reformation parallel to the basal turn of the cochlea in the evaluation of the retrotympanum and hypotympanum to complete the standard CT examination of the temporal bone obtained with axial and coronal images.

MATERIALS AND METHODS

We studied 30 patients aged 18-79 years for a total of 60 normal petrous pyramids. All examinations were performed on a multislice CT (MSCT) scanner (Sensation 16, Siemens, Erlangen, Germany) with axial volumetric acquisition and completed with reformations of coronal and coronal-oblique images. MSCT scan parameters for axial acquisition were set as follows: 0.75-mm scan collimation, FOV 300 mm, 170 mAs. Axial images were reconstructed at 0.7-mm thickness and with a reconstruction increment of 0.5 mm using a high-resolution bone algorithm.

RESULTS

Coronal oblique MPR CT reformations provided additional information with respect to standard CT images in all cases. In particular, they enabled measurement of the craniocaudal and laterolateral diameters of the sinus tympani. In all cases, there was optimal visualisation of the ponticulus and subiculum. Analysis of the pyramidal eminence was improved thanks to its visualisation in profile. Moreover, we obtained an optimal representation of the hypotympanum, which was always exhaustively explored with only one reconstruction. Finally, in all cases, it was possible to identify the facial nerve canal and main vascular structures and to measure the distance between these and the sinus tympani, pyramidal eminence and hypotympanum. The coronal oblique CT reformation was of no advantage in the evaluation of the fossa of the oval window and the niche of the round window.

CONCLUSIONS

Coronal oblique MPR CT reformation should not be considered an alternative to the standard CT examination, but it can represent a valid integration to provide additional information on particularly crucial districts characterised by frequent involvement of inflammatory and/or expansile disease and because of their difficult endoscopic approach. Moreover, it can represent a meaningful aid to optimise surgical planning thanks to its different perspectives of observation.

MR pyelography in the assessment of hydroureteronephrosis: single-shot thick-slab RARE versus multislice HASTE sequences

BACKGROUND

We used magnetic resonance (MR) pyelography to compare the value of thick-slab single-shot rapid acquisition with relaxation enhancement (RARE) sequence with that of multislice half-Fourier acquisition single-shot turbo-spin-echo (HASTE) sequence in evaluating the full spectrum of morphologic features in a group of patients with hydronephrosis.

METHODS

MR pyelographic images, with the use of thick-slab RARE and multislice HASTE sequences in 90 patients, were evaluated for image quality, presence of hydronephrosis, and level and cause of obstruction.

RESULTS

HASTE sequences provided images of better quality than did RARE sequences (p < 0.001). There was no statistically significant difference in demonstrating the presence of hydronephrosis (p = 0.5) and level of obstruction (p = 0.125). Sensitivity, specificity, and accuracy in diagnosing cause of obstruction were 61.7%, 62.5%, and 62%, respectively, for RARE sequences and 80%, 82.5%, and 81%, respectively, for HASTE sequences, with a statistically significant difference (all p < 0.05).

CONCLUSION

Multislice HASTE sequence provides better diagnostic information than does thick-slab RARE sequence, particularly in evaluating the cause of obstruction.

Twisted ovarian fibroma with high signal intensity on T1-weighted MR image: a new sign of torsion of ovarian tumors?

Torsion of ovarian tumors is often difficult to diagnose, because of non-specific clinical, laboratory, and imaging findings. We report a case of twisted ovarian fibroma whose main characteristic was the presence of large areas of high signal intensity on both T1- and T2-weighted MR images due to the passive congestion of the mass. This previously unreported finding should be considered a sign of ovarian torsion and may facilitate prompt surgical intervention.

MR white lung sign: incidence and significance in pulmonary consolidations

PURPOSE

The presence of a pulmonary consolidation with a signal intensity comparable with that of the static fluid on heavily T2-weighted MR images has been named the "MR white lung sign." This sign has been described in mucinous bronchioloalveolar carcinoma (BAC). Our purpose was to establish the frequency and significance of this sign in pulmonary consolidations of varied causes.

METHOD

In this prospective study, 83 patients with pulmonary consolidation underwent MR examination between January and December 1999. Segmental or lobar consolidations were due to pneumonia without central obstruction (n = 22), pneumonitis with central obstruction (n = 21), cicatricial atelectasis (n = 8), passive atelectasis (n = 10), radiation pneumonitis (n = 8), mucinous BAC (n = 5), infarction (n = 3), bronchiolitis obliterans organizing pneumonia (n = 3), nonmucinous BAC (n = 2), and lymphoma (n = 1). The MR white lung sign was considered present when the signal intensity of a pulmonary consolidation was comparable with that of the static fluid on heavily T2-weighted images obtained with MR hydrography sequences. Interobserver agreement, sensitivity, and specificity of the white lung sign in diagnosing mucinous BAC were calculated.

RESULTS

The MR white lung sign was present in 7 (8%) of 83 consolidations, including 5 (100%) of 5 cases of mucinous BAC and 2 (10%) of 21 cases of obstructive pneumonitis. The frequency of the white lung sign was 100% in mucinous BAC and 2.6% in consolidations due to other causes. The difference was statistically significant (p < 0.05).

CONCLUSION

The white lung sign is an uncommon finding in pulmonary consolidations evaluated with heavily T2-weighted sequences. However, the sign is characteristic of mucinous BAC and adds specificity to the radiologic diagnosis.

Perineural spread in a case of sinonasal sarcoidosis: case report

We report a case of sinonasal sarcoidosis with perineural spread along the trigeminal and vidian nerves in which primarily MR imaging but also CT allowed excellent visualization of this infiltration.

CT and MR findings in neoplastic perineural spread along the vidian nerve

The aims of this article are to describe the findings of perividian tumor spread and to compare the accuracy of MRI and CT in diagnosing perineural metastasis along the vidian nerve. Moreover, the frequency of perividian metastasis in patients with head and neck cancer was evaluated. The CT and MR examinations of 98 consecutive untreated patients with histologically proven head and neck cancer were retrospectively reviewed. We considered as criteria for perineural tumor spread along the vidian nerve the following CT and MR findings: For CT (a) enlargement of the pterygoid canal, (b) erosion of its bony wall, and (c) obliteration of its normal fatty content; and for MR (a) enlargement of the vidian nerve, (b) enhancement of the nerve, and (c) obliteration of fat, particularly in the anterior part of the pterygoid canal. Ten patients met the selected criteria for perineural metastasis, which was bilateral in 3 patients, with a total of 13 vidian metastases. The CT scans demonstrated unilateral involvement of the vidian nerve in 9 patients. The MRI scans showed 13 perineural metastases. In 3 patients MR scans demonstrated involvement of four vidian nerves that appeared normal on CT examinations. The diagnostic difference between CT and MRI was statistically significant (Fisher's exact test; p = 0.04). Perineural spread along the vidian nerve is an event more frequent than previously reported and must be investigated with a careful imaging technique. Although a major limitation of our study is the lack of histological proof, the MR finding of a significant enhancement of the nerve, whether enlarged or normal in size, could be considered very suggestive of this kind of metastatic spreading, particularly if associated with simultaneous involvement of the neighboring structures (pterygopalatine fossa, foramen lacerum, trigeminal branches, etc.).

Chronic infiltrative lung diseases: value of gadolinium-enhanced MRI in the evaluation of disease activity--early report

STUDY OBJECTIVE

To determine the value of gadolinium-enhanced MRI in the assessment of disease activity in chronic infiltrative lung diseases (CILDs).

DESIGN

Retrospective study.

SETTING

University hospital.

MATERIALS AND METHODS

Twenty-five consecutive patients with CILD were studied. The following diseases were diagnosed: sarcoidosis (n = 10), bronchiolitis obliterans organizing pneumonia (n = 3), usual interstitial pneumonia (n = 4), radiation pneumonia (n = 2), desquamative interstitial pneumonia (n = 1), rheumatoid lung (n = 1), vasculitis (n = 1), alveolar proteinosis (n = 1), bronchioloalveolar carcinoma (n = 1), and chronic eosinophilic pneumonia (n = 1). In each patient, the disease activity was assessed by one or more of the following studies: BAL (n = 18), gallium-radioisotope lung scanning (n = 6), serum angiotensin-converting enzyme assay (n = 10), and open lung biopsy (n = 4). T1-weighted breath-hold MRI studies were obtained before and after IV injection of gadolinium. The MRI examinations were analyzed to assess the presence or absence of lesional enhancement.

RESULTS

The presence of enhanced pulmonary lesions was seen in 14 patients. All of these patients had active disease. Of the 17 patients with active disease, 14 had enhanced lesions, and 3 had unenhanced lesions. Pulmonary lesions were not enhanced in any patients with inactive disease. The difference was statistically significant (Fisher Exact Test, p < 0.05).

CONCLUSION

Gadolinium-enhanced MRI may prove to be a useful tool in assessing disease activity in CILDs.

Magnetic resonance imaging of bronchioloalveolar carcinoma

The purpose of this study is to describe the magnetic resonance (MR) features of bronchioloalveolar carcinoma. MR examinations of 18 patients with proven bronchioloalveolar carcinoma were reviewed. Detection at computed tomography (CT) and pathologic confirmation were the entry criteria. Nine patients had a solitary nodule, three patients a lobar consolidation, and six patients had diffuse disease. For each patient, both breath-hold T2-weighted fast spin-echo, and breath-hold T1-weighted gradient-echo images, before and after injection of gadolinium, were available. Nine patients with pulmonary consolidation or diffuse disease had also heavily T2-weighted MR imaging (Haste or TSE 240; Siemens, Erlangen, Germany). MR imaging showed pulmonary abnormalities in 17 of 18 patients. Unenhanced T1-weighted and T2-weighted images depicted tumor in 16 of 18 patients. Contrast-enhanced T1-weighted images showed tumor in 17 of 18 patients. In no case did MR imaging depict abnormalities corresponding to the ground-glass opacities seen on CT scans. In three patients with mucinous bronchioloalveolar carcinoma, heavily T2-weighted images showed lesions isointense with respect to static fluid of the human body. In conclusion, the ability of MR imaging in detecting small nodules and ground-glass opacities is limited. However, heavily T2-weighted sequences are able to show the presence of mucin. This is useful information because mucinous bronchioloalveolar carcinoma carries a poor prognosis.

Diagnostic pitfalls of breath-hold MR urography in obstructive uropathy

Breath-hold MR urography (MRU) is being used with increasing frequency to evaluate urinary tract pathology. Although multiple studies have documented the accuracy of breath-hold MRU in the evaluation of obstructive uropathy, pitfalls associated with this technique may result in diagnostic errors. This essay illustrates both technical and interpretive pitfalls of MRU and suggests strategies for their recognition and avoidance.

Sudden unilateral deafness with endolymphatic sac adenocarcinoma: MRI

A 30-year-old man presented with sudden left deafness and vertigo. CT showed an osteolytic retrolabyrinthine tumour of the left temporal bone. High signal from the tumour and labyrinth was seen on fat-suppressed T 1-weighted images. At surgery, a haemorrhagic papillary-cystic adenocarcinoma of the endolymphatic sac was found.

Mucinous cystadenocarcinoma of the lung: CT-pathologic correlation in three cases

Mucinous cystadenocarcinoma (MCA) is a rare tumor that is considered to be a cystic variant of mucin-producing lung adenocarcinoma. MCA expands grossly by storing mucus and contains few neoplastic cells. We present the CT images of three patients with MCA and correlate them with pathologic specimens. The CT findings of MCA include a uniform low-attenuation, focal thickening of the cystic wall and enhancing septa.

Computed tomography halo sign in pulmonary nodules: frequency and diagnostic value

On computed tomography (CT) scanning, a ground-glass opacity zone surrounding a pulmonary nodule has been named the computed tomography (CT) halo sign. To investigate the frequency and diagnostic value of the CT halo sign, the authors reviewed the CT examinations of 305 patients with proven diseases producing solitary or multiple nodules. The CT halo sign was seen in 22 patients (7%). Eleven patients had a solitary nodule; five patients had multiple nodules; and six patients had nodules associated with areas of pulmonary consolidation, or ground-glass opacity, or both. Solitary nodules were the result of bronchioloalveolar carcinoma (n = 5), tuberculoma (n = 2), squamous cell carcinoma, non-Hodgkin lymphoma, myxovirus infection, and metastasis (n = 1 each). Multiple nodules were the result of metastasis (n = 2), Kaposi sarcoma (n = 2), and Wegener granulomatosis (n = 1). Nodules associated with areas of consolidation or ground-glass opacity were the result of metastasis (n = 2), bronchioloalveolar carcinoma, bronchiolitis obliterans organizing pneumonia, eosinophilic pneumonia, and invasive pulmonary aspergillosis (n = 1 each). The data showed that the CT halo sign is a nonspecific finding. It is known that in immunocompromised patients the CT halo sign should suggest invasive pulmonary aspergillosis, Kaposi sarcoma, and lymphoproliferative pulmonary disorders. However, in immunocompetent patients, the authors found that a solitary nodule with the CT halo sign and pseudocavitations has a high likelihood of being a bronchioloalveolar carcinoma.

Radiolucencies and cavitation in bronchioloalveolar carcinoma: CT-pathologic correlation

Bronchioloalveolar carcinoma (BAC) is a polymorphic lung cancer the incidence of which is rising. The presence of intratumoral radiolucencies is an important feature of bronchioloalveolar carcinoma. The aim of this study was to present pictorially the spectrum of intratumoral radiolucencies visible in BAC. In 57 BACs studied with thin-slice CT, we identified six types of radiolucencies: (a) patent intratumoral bronchioles (air bronchiologram); (b) pseudocavitations; (c) cavitation; (d) serpentine radiolucencies; (e) internal alveologram; and (f) multiple cystic lesions.

[Magnetic resonance pyelography: clinical use of ultrafast breath-hold sequences in obstructive uropathy. Personal experience]

INTRODUCTION

We investigated the diagnostic yield of MR pyelography (MRP) performed with two ultrafast breath-hold sequences in obstructive uropathy patients.

MATERIAL AND METHODS

Thirty-four patients with US demonstration of urinary tract dilation were examined with MRP at 1.5 T and with a standard body coil. HASTE sequences (TE 66, ETL 128, FA 180 degrees, 1 NEX, MA 240 x 256, slice thickness 4 mm, TA 13 s) were always performed and 26/34 patients were also examined with single-shot TSE sequences (TE 1100, ETL 240, FA 150 degrees, 1 NEX, slice thickness 7 cm, MA 240 x 256, FS, TA 7 s); 20/34 patients were given 500 mL superparamagnetic contrast agent (Lumirem). MRP findings were interpreted independently by two radiologists and analyzed for image quality, the presence/absence of dilation, the obstruction grade (mild, moderate, severe), site (intrarenal; ureteropelvic junction; proximal, mid-, distal ureter; indeterminate) and cause (intrinsic obstruction from a stone or other conditions; stenosis; indeterminate cause). The sensitivity, specificity, positive and negative predictive values for the detection of urinary tract dilation were calculated for each reviewer and interobserver agreement was calculated with the k analysis relative to the presence, grade, site and cause of urinary tract dilation.

RESULTS

MRP examinations were considered technically adequate in all cases by both observers. As for the presence of urinary tract dilation, the values were 100% for the first observer and 97%, 100%, 100%, and 95%, respectively, for the second observer. Interobserver agreement was .98 for dilation presence (excellent), .80 for dilation degree (excellent), .62 for dilation site (good) and finally .69 for dilation cause (good).

DISCUSSION AND CONCLUSIONS

MRP performed with the ultrafast breath-hold technique provides very good results in diagnosing urinary tract dilation, as well as the obstruction grade, site and cause, with results equal or even superior to those of non-breath-hold sequences. Ultrafast MRP lasts only 10 minutes, meaning it occupies the magnet shortly and costs less: it can be thus considered a routine alternative to conventional diagnostic imaging, especially ivp, in the evaluation of obstructive uropathy.

[Use of oral superparamagnetic contrast media in cholangiopancreatography with TSE single-shot magnetic resonance]

PURPOSE

To investigate the yield of an oral superparamagnetic contrast agent (Lumirem) in turbo spin echo (TSE) single-shot MR cholangiopancreatography (MRCP) in patients candidate to laparoscopic cholecystectomy.

MATERIAL AND METHODS

Thirty patients (mean age: 52.2 years) scheduled for laparoscopic cholecystectomy underwent MRCP with TSE single-shot sequences. To cover the biliary tree, thick-section TSE images were acquired according to the cross-sectional location of the biliary tract. Six 50-mm images progressively rotated by 30 degrees each were acquired during breath-holds. The precontrast images were obtained before the negative oral contrast agent was administered. The postcontrast images were acquired 10 minutes after oral contrast agent administration. Two observers made a qualitative evaluation on all images: the contrast enhancement was assessed comparing the pre- and postcontrast images of each examination on the basis of signal intensity in the stomach and duodenum, giving a score on a graduate scale. The greater yield of postcontrast images was validated by statistical analysis. The actual diagnostic improvement obtained with postcontrast images was validated for every single case.

RESULTS AND CONCLUSIONS

The greater yield of postcontrast images was statistically significant in the common bile and cystic ducts, but not in the gallbladder and Wirsung duct. Better images were obtained in 22/30 patients. The actual diagnostic improvement in the visualization of the common bile and cystic ducts was statistically significant in 7/30 patients. To conclude, administering an oral negative contrast agent improved image quality and the diagnostic yield. The agent was well tolerated and safe and we suggest its use in TSE single-shot MRCP of the patients candidate to laparoscopic cholecystectomy.

[Significance of the circumferential involvement of the superior horn tip of the thyroid cartilage in pharyngo-laryngeal cancer]

The term "laryngopharyngeal carcinoma" indicates an advanced tumor involving both the supraglottic larynx and the pharynx in which the lesion origin may be difficult to assess. In 1981, Larsson et al. reported on the CT signs useful to distinguish the laryngeal/hypopharyngeal origin of advanced laryngopharyngeal carcinoma. We describe a new CT sign which may serve this purpose, namely the involvement of the thyroid cartilage superior horn tip. The thyroid cartilage superior horn, in fact, is involved early in the lesions originating in the pyriform sinus because of its close anatomic relationship with the posterolateral wall of the hypopharynx. MATERIALS AND METHODS. To assess the significance and specificity of this sign, we examined 15 patients with advanced laryngopharyngeal carcinoma with clinical, endoscopic and surgical evidence suggestive of tumors originating in the pyriform sinus. All CT examinations were performed with contiguous 4 mm slices before and after i.v. administration of iodinated contrast agents. Eighteen patients with surgically confirmed advanced supraglottic carcinoma were also examined.

RESULTS

The thyroid cartilage superior horn tip was involved only in 3/18 supraglottic carcinoma patients; transcommissural infiltration of the larynx, involving both pyriform sinuses, was found in 2 of these cases and extensive invasion of the whole thyroid cartilage and of the cricoid ring in 1 case.

CONCLUSIONS

The thyroid cartilage superior horn tip is a reliable sign of the pyriform sinus origin of advanced laryngopharyngeal cancer which is both sensitive (100%) and specific (83%). Moreover, this sign could play a major role because it represents, in most cases, the only and earliest sign of cartilage involvement. Finally, the encasement of the thyroid cartilage superior horn tip by abnormal tissue indicates tumor spread beyond the posterior pharyngeal wall. Therefore, these data can be very important for its early detection and useful for subsequent surgical planning.

[The angiogram sign in lung consolidation: what is its diagnostic value?]

The angiogram sign in chest CT is the demonstration of normally enhanced pulmonary branches within hypoattenuating lung parenchyma consolidation. In a retrospective review of the chest CT exams performed in a 2-year period, we identified the angiogram sign in 10 patients with lung consolidation; the diagnosis was central lung tumor with obstructive pneumonia in 4 patients, bronchioloalveolar carcinoma in 2 patients, postirradiation fibrosis in 1 patient, tuberculous pneumonia in 1 patient, lung lymphoma in 1 patient and metastasis from pancreatic tumor in 1 patient. The diagnosis was made with cytology and/or surgical specimen in 9 patients and with clinical-radiologic follow-up in 1 patient. The density, air and mucous bronchogram and the volume loss in the consolidated lung were also considered. The consolidated lung density was < 30 HU in 5 patients-one bronchioloalveolar carcinoma, one metastasis from pancreatic carcinoma and 3 obstructive pneumonia cases-, while it was > 30 HU in the extant 5 patients. The air bronchogram sign was observed in 4 cases-one bronchioloalveolar carcinoma, one metastasis, one postirradiation fibrosis and one lung lymphoma-, while a mucous bronchogram was observed in 3 patients with obstructive pneumonia. Lung volume was reduced only in 2 patients-one obstructive pneumonia and one postirradiation fibrosis. In our opinion, the CT angiogram sign must be considered a poorly specific sign, because it can be found in many pathologic processes, both benign and malignant. If associated with the other features of lung consolidation, the CT angiogram sign can help diagnose, together with clinical findings and the patient's history, the pathologic condition. Particularly, the angiogram sign within a hypoattenuated lung consolidation area can be found in obstructive pneumonia, while the angiogram sign within a hypoattenuated consolidation with an air bronchogram probably indicates a mucinous carcinoma with lipidic growth.

Computed tomography visceral adipose tissue volume measurements of Italians. Predictive equations

OBJECTIVES

To evaluate total visceral adipose tissue (AT) volumes in relation to single slices of visceral AT area measured at different levels and to other simple anthropometric measurements.

DESIGN

Only outpatients examined in a metabolic unit were considered; subjects without conditions known to affect AT distribution who gave their informed consent were recruited.

SETTING

All subjects were hospitalized in the Department of Internal Medicine of the University of Messina.

SUBJECTS

90 adult subjects of which 18 men and 42 pre- and 30 post-menopausal women. Ages ranged from 18 to 69 years and body mass indexes ranged from 22 to 50.

INTERVENTIONS

The AT volume was calculated by computed tomography from the AT area of five scans and from the distances between these scans.

RESULTS

AT area at the level of the 2nd-3rd lumbar vertebra had by itself the highest predictive power in men (s.e. = 6.8%), in post-menopausal women (s.e. = 7.4%) and, together with age, in pre-menopausal women (s.e. = 14%). Of the non-radiological parameters it was waist circumference, together with age, which showed the highest predictive power in men (s.e. = 21%), pre-menopausal women (s.e. = 25%) and, together with height, in post-menopausal women (s.e. = 33%).

CONCLUSIONS

A single scan measurement at the lumbar level was confirmed to be representative of total visceral AT volume. Waist circumference was the non-radiological parameter that best correlated with volume.

Air-space pattern in lung metastasis from adenocarcinoma of the GI tract

PURPOSE

We retrospectively reviewed a series of proven lung metastasis to evaluate the frequency and CT features of metastases showing an air-space (lepidic) pattern of growth.

METHOD

CT examinations of 65 patients with proven lung metastasis from GI carcinomas were reviewed by three observers. Four CT features were used to classify lesions as air-space metastases: (a) air-space nodules; (b) parenchymal consolidation containing air bronchogram and/or showing angiogram sign; (c) focal or extensive ground-glass opacities; and (d) nodules(s) with a "halo" sign.

RESULTS

Six of 65 patients showed air-space metastases: three from pancreatic carcinoma, two from colonic carcinoma, and one from jejunal carcinoma. In one case, metastasis appeared as extensive parenchymal consolidation associated with ground-glass opacities; in one as an area of ground-glass opacity; in one as an extensive parenchymal consolidation with air bronchogram; in one as parenchymal consolidations with angiogram sign and multiple nodules, some of these with halo sign; in one as air-space nodules and patchy air-space consolidations; and in one as a solitary nodule with halo sign.

CONCLUSION

Our study shows that air-space lung metastasis from GI carcinomas is uncommon but not rare. On CT as well as microscopically, differential diagnosis between air-space metastasis and bronchioloalveolar carcinoma may be impossible.

Subcapsular renal spread of a pancreatic pseudocyst

In pancreatitis, the fluid collection may extend to unusual sites and organs and form a pseudocyst. We present US and CT findings of a pancreatic tail pseudocyst extending into the subcapsular space of the left kidney.

[Computerized tomography in the assessment of obstructive jaundice caused by hepatic hydatid cysts]

This paper reports on the CT findings of obstructive jaundice caused by hydatid cysts of the liver, which are an unusual event occurring in 5-10% of cases. Thus, only a few reports can be found in the literature dealing with the CT features of this syndrome. Eight patients with obstructive jaundice were selected from 87 patients with hydatid disease of the liver and examined with CT. The CT diagnosis of rupture into the largest bile ducts is based upon the demonstration of hepatic hydatid cysts together with intrabiliary hydatid sand, membranes and scolices and/or the identification of parietal discontinuity with communication between the cyst and the biliary tree. Rupture into the largest bile ducts was demonstrated in 7 patients. The following CT patterns were observed: 1) intrahepatic biliary tract dilatation (all cases); 2) extrahepatic biliary tract dilatation (6 cases); 3) cyst wall interruption (5 cases--in 3 of them the communication between the cyst and the dilated bile duct was demonstrated); 4) daughter cysts, fragmented membranes or hydatid sand in the biliary tree (5 cases); 5) hydatid material in the gallbladder (1 case) and, finally, disappearance of the daughter cyst visible on a previous CT examination (1 case). In another patient, the diagnosis of compressive jaundice without biliary communication was suggested because a bulky hydatid cyst was found near the hilum of liver. CT findings were confirmed with ERCP or at surgery. CT failed to reveal small tears with minute biliary radicles, which are usually asymptomatic, whose diagnosis could be made only with preoperative cholangiography. Hydatid cysts of the liver can cause obstructive jaundice because of main bile duct compression or of large bile duct perforation with consequent passage of hydatid material into the biliary tree. This complication should be promptly managed surgically to avoid potentially fatal complications, which makes a preoperative diagnosis essential.

[Computerized tomography in the assessment of metastatic facial adenopathy]

The facial lymph nodes are classified in five groups: mandibular, buccinator, infraorbital, malar and retrozygomatic nodes. This paper reports the CT appearance of neoplastic involvement of these nodes, an unusual and not well documented event. The CT examinations of 62 patients with a history of primary or recurrent cancer of the epidermal structures of the face, oral cavity and sinonasal region were retrospectively reviewed to assess the presence of facial adenopathy. Nine cases of neoplastic involvement of facial nodes were found. Most commonly the buccinator nodes (4 cases) were involved, the infraorbital, mandibular (2 cases) and retrozygomatic nodes (1 case) being less commonly involved. No malar nodes were found. Neoplastic involvement of these nodes was caused by squamous cell carcinoma in 6 cases, by adenocarcinoma in 2 cases and by a lymphoma in 1 case. Normal nodes could not be confidently identified on CT studies. CT diagnosis of neoplastic involvement of facial nodes is based on the presence of a nodular lesion which lies along the lymphatic pathways of the primary neoplasm in an anatomically compatible location. CT diagnosis of facial nodes is very important for treatment planning if the nodes are deep or at a distance from primary cancer. This is especially true for retrozygomatic and buccinator nodes.

[Computerized tomography in gaseous hypotonic duodenography in the study of the pancreatico-duodenal area]

This study was aimed at assessing the role of CT-hypotonic gaseous duodenography in the study of the pancreatic-duodenal region. Forty-two patients with malignancies in this region were examined with CT of the upper abdomen followed by CT-hypotonic gaseous duodenography (30 pancreatic head cancers, 7 main bile duct and 5 ampullary lesions). In 20 of 28 cases of pancreatic head carcinoma, CT-hypotonic gaseous duodenography yielded more pieces of information than baseline abdominal CT and was also more useful in small pancreatic head cancers, < 4 cm diameter. In 4 of these patients, CT-hypotonic gaseous duodenography better demonstrated the pancreatic lesions which conventional CT had demonstrated poorly. In contrast, CT-hypotonic gaseous duodenography was less useful in main bile duct carcinomas, depicting focal duodenal infiltration in only 1 of 7 cases. In all ampullary tumor patients (5/5), CT-hypotonic gaseous duodenography demonstrated intraduodenal lesions. The authors conclude that CT-hypotonic gaseous duodenography is a useful technique to investigate small pancreatic head cancers and the method of choice to demonstrate ampullary lesions.

[Bronchiolo-alveolar carcinoma. The computed tomographic picture and histological correlations]

Twenty-one CT examinations of 18 patients with a known bronchioloalveolar carcinoma in the lung were retrospectively reviewed to describe the CT features of bronchioloalveolar carcinomas. Surgical specimens were available in 13 cases in which CT-histologic correlation was also obtained. In 5 patients the diagnosis was made with cytology and confirmed with radiologic-clinical follow-up. Three patients were reexamined for relapses 6-20 months after the resection of a localized carcinoma. Carcinomas exhibited 3 radiologic patterns: a) solitary pulmonary nodule (11 cases), b) mass or pulmonary consolidation (3 cases) and c) multicentric or diffuse disease (7 cases). Solitary nodular bronchioloalveolar carcinomas were associated with irregular or spiculated margins in 9 of 11 patients. In some cases internal inhomogeneity due to bubble-like radiolucencies was demonstrated. At pathology, bubble-like radiolucencies correlated with air-containing cystic spaces lined by neoplastic epithelium or patent and dilated bronchi. Some nodules exhibited linear and serpentine internal radiolucencies. Pathology demonstrated them to be consistent with patent intratumoral bronchioles (air bronchiologram) and air-containing neoplastic glandular spaces, respectively. In two cases a perinodular ground-glass halo was demonstrated surrounding the nodule (CT halo sign), due to perinodular lepidic tumor growth. Massive or ground-glass opacity involving a pulmonary segment or a lobe was another CT pattern of bronchioloalveolar carcinoma. An air bronchogram was usually demonstrated within the lesion. In the mucinous type of bronchioloalveolar carcinoma, pulmonary consolidations had a low CT value because of the large amount of intratumoral mucus. The diffuse type of tumor presented as multiple pulmonary nodules or multiple pulmonary consolidations, or both. In two cases multiple nodules were associated with carcinomatous lymphangitis. In conclusion, bronchioloalveolar carcinoma should be considered in the differential diagnosis of solitary pulmonary nodules, multiple pulmonary nodules and chronic alveolar opacities. The diagnosis of a bronchioloalveolar carcinoma is of great value since surgery can help nearly 70% of the patients at this stage recover.

CT-pathologic correlation in nodular bronchioloalveolar carcinoma

OBJECTIVE

We retrospectively reviewed CT and pathologic examinations in resected nodular bronchioloalveolar carcinomas (BACs) to correlate the histology with the appearance of the nodules on preoperative thin section CT images.

MATERIALS AND METHODS

Thin section CT scans of 11 patients with nodular BAC were reviewed by two observers. In each case, size, tumor-lung interface, and internal characteristics of the nodule were recorded and correlated with histopathologic examinations.

RESULTS

Computed tomography showed a large bronchus leading to or contained within the nodule in 36%; spiculated, lobulated, or irregular borders in 82%; pleural retraction in 36%; internal inhomogeneity in 45%; and a zone of intermediate attenuation surrounding a higher attenuation nodule and separating it from the surrounding lung parenchyma (the CT halo sign) in 18% of the 11 BACs. In two lesions internal serpentine radiolucencies could be seen. Histopathologic studies showed this correlated with the air-containing glandular spaces of the tumor.

CONCLUSION

The CT halo sign and serpentine radiolucencies should be added to the list of the CT findings of nodular BAC. However histologic examination is required to confirm the diagnosis of BAC.

Small bronchogenic carcinomas presenting as solitary pulmonary nodules. Bioptic approach guided by CT-positive bronchus sign

To evaluate the utility of the CT bronchus sign in making a choice between transbronchial biopsy (TBB) and transthoracic needle aspiration (TTNA) as the first diagnostic procedure in a patient with a solitary pulmonary nodule (SPN), we reviewed the results of TBB and TTNA in 26 patients who had a bronchogenic carcinoma less than 3 cm, studied with thin-section CT. The patients were divided into two groups. Group 1 included ten cases with a third- to fifth-order bronchus sign. Group 2 included two cases with a sixth-order bronchus sign and 14 cases with absence of a bronchus sign. TBB was performed in all the patients; conversely, TTNA was carried out in 22 patients. In group 1, TBB gave a diagnostic yield in eight (80 percent) of ten patients, while TTNA was positive in three (42 percent) of seven patients (p > 0.05). Conversely, in group 2, results of TBB were normal in all the patients, while TTNA gave a diagnosis in 10 (66 percent) of 15 patients (p < 0.05). We think that TBB should be considered the method of choice in diagnosing SPNs associated with a third- to fifth-order bronchus sign; conversely, TTNA is more useful than TBB in diagnosing SPNs in the presence of a more peripheral bronchus sign or with the absence of a bronchus sign. In conclusion, we suggest routine evaluation with thin-section CT of each SPN to optimize diagnostic management.

CT "halo sign" in pulmonary tuberculoma

The CT halo sign has been described as the CT finding of a low-attenuation zone surrounding a pulmonary nodule. It is an early clue to the diagnosis of invasive pulmonary aspergillosis. We describe a case of CT halo sign associated with a pulmonary tuberculoma. Therefore, we think that a diagnosis other than invasive pulmonary aspergillosis should be considered in the presence of the CT halo sign in immunocompetent patients.