Morphologic variants of the Cerebral Arterial Circle on computed tomographic angiography (CTA): a large retrospective study.

PURPOSE: To confirm and illustrate the great variability of morphology of the Cerebral Arterial Circle (CAC)-also commonly called "Circle of Willis"-in current clinical Computed Tomography Angiography (CTA) practice. METHODS: Computed Tomographic Angiographic 3D Volume Rendering reconstructions of the CAC performed in a series of 511 patients were retrospectively reviewed and classified following their anatomic configuration. RESULTS: An amount of 27 CAC configurations were listed. Complete and "nearly complete" (1 missing segment) CACs were found in 115 (22.58%) and 157 (28.6%) patients. The posterior arch was much more frequently incomplete (374 patients = 73.18%) than the anterior arch (96 patients = 18.4%). The main cause was a high prevalence of missing posterior communicating arteries (PCoAs). The left or right PCoA were unilaterally lacking in 156 patients (30.53%) and both PCoAs were lacking in 179 patients (35.02%). Cases with 2 and 3 missing segments were observed in 184 (36%) and 44 patients (8.6%). Precarious situations were also identified including 7 cases (1.4%) of complete isolation of the middle cerebral artery (MCA), 11 cases (2.15%) of absence of interhemispheric supply, 205 cases (40.1%) of full separation of the carotid and vertebra-basilar (VB) territories and 44 cases (8.6%) of full separation of the three main arterial axes (both ICAs and VB). The prevalence of Fetal Posterior Cerebral Arteries (FPCA) variants was also reported. A "Full" FPCA was found unilaterally in 48 (9.4%) and bilaterally in 13 (2.54%) of patients. Apart from agenesis and hypoplasia reported in our study, various other variations of the anterior complex of the CAC (ACoA and A2 segments of the ACA) were also noted. CONCLUSION: CTA with 3D Volume Rendering may powerfully assess the numerous variations of the CAC. This assessment is of prime importance for the evaluation of patients presenting with risk factors or in whom neurosurgery, cardiac surgery, interventional radiology or carotid endarterectomy (CEA) are being considered.

Asymptomatic left isomerism with preduodenal portal vein: computed tomography appearance.

Left isomerism (polysplenia), one of the two major variants of heterotaxia with right isomerism (asplenia), may be rarely diagnosed in adulthood. Most cases are nevertheless asymptomatic and incidentally detected during imaging or surgery performed for unrelated conditions. We hereby report a case of left isomerism fortuitously diagnosed in a 55-year-old man with unrelated tachy-cardiomyopathy. Thoraco-abdominal computed tomography revealed a typical preduodenal portal vein (PDPV) associated with a large series of other occult anatomic variations comprising: polysplenia, agenesis of both pancreatic body and tail, complete non-rotation of the bowel and finally azygous continuation of the inferior vena cava. Subtle but highly specific thoracic features of left isomerism were also found with a bilobed right lung and bilateral long hyparterial main bronchi. The features of adult left isomerism are remembered with special attention to the PDPV.

Computed tomographic angiography (CTA) diagnosis of a rare meandering right pulmonary vein (MRPV).

Meandering right pulmonary vein (MRPV) is an exceedingly rare congenital pulmonary vascular variant with less than 20 reported cases. MPVR is a tortuous aberrant venous drainage of the right pulmonary upper lobe anastomosing with the right lower pulmonary vein instead of directly joining the left atrium. The variant is benign with an orthotopic venous drainage without any kind of shunting. The differential diagnosis mostly comprises the scimitar syndrome but also primary varix, arteriovenous malformations, and pulmonary sequestration. We report a case of MRPV fortuitously diagnosed in a 70-year-old patient. Multi-detector computed tomographic angiography (CTA) with MPR, MIP, and 3D reconstructions allowed the diagnosis obviating the need for invasive procedures.

Hepatic "hot-spot" on angio-computed tomography: the role of inferior Sappey's and ensiform veins.

Hepatic "hot spots" in anterior paraumbilical hepatic segments of patients suffering from superior vena cava syndrome may be revealed by angio-computed tomography. They may be due to a collateralizing system, the epigastric-paraumbilical venous system (EPVS), which enters the liver as a "third inflow". We report a typical case emphasizing the role of the ensiform and inferior Sappey's veins which constitute typical anatomic components of the EPVS.

A case of reversed intestinal rotation revealed by volvulus in adult: anatomo-radiological correlations.

We report a case of reversed rotation (RR) of the midgut, the rarest form of intestinal malrotation (IMR), revealed by a chronic volvulus, in a 42-year-old woman presenting with episodes of abdominal pain occurring after heavy meals. The complete preoperative diagnosis was obtained by contrast-enhanced computed tomography (CT). Classical signs of volvulus were associated with typical findings of RR comprising an unusual position of the third duodenum in front of the mesenteric vessels and a very unusual location of the transverse colon behind these vessels. Complete absence of fixation of the right colon allowed secondary volvulus. A detailed reminder of the embryology of IMR and RR is presented.

Inferior vena cava reconstruction with a superficial femoral vein graft after resection of a venous leiomyosarcoma.

Leiomyosarcoma is a rare malign neoplasm, representing about 5-7% of all tissue sarcomas while inferior vena cava leiomyosarcomas accounts for only 1%. This paper presents the case of a 74 years old patient that was diagnosed with an abdominal venous leiomyosarcoma involving the inter-renal segment of the inferior vena cava. Tumor was treated by complete in bloc resection. Reconstruction of the vascular axis was performed with an autologous venous tube graft achieved with segments of the right superficial femoral vein. Recurrent free survival and freedom from local or systemic recurrence was observed at 2 years after the intervention thanks to the aggressive radical surgical management.

Uncommon CT imaging of the hepatic falciform artery in patients presenting with very unusual variants of gastrointestinal arteries: report of two cases.

The hepatic falciform artery (HFA) may be found in 68% of subjects in post-mortem dissections. It is well known by interventional radiologists who perform selective hepatic angiography. The reason essentially results from the potential supraumbilical skin complications which may produce by the distribution of chemotherapeutic agents through the HFA after transcatheter chemoinfusion or chemoembolization for liver tumors. Nevertheless, the spontaneous visualization of the HFA remains very unusual in current abdominal CT practice. We hereby report the demonstration of a patent HFA during conventional abdominal CT in two patients presenting without liver disease but in which very unusual variants of the gastrointestinal arteries were simultaneously found. The first patient had a common celiomesenteric trunk and the second had a severe compression of both the celiac trunk and superior mesenteric artery by the median arcuate ligament of the diaphragm. We shortly review the literature about these rare variants. We hypothesize that the HFA was spontaneously visible in our patients because of hypertrophy due supplying collateralization.

Perforation of the gastrointestinal tract caused by inadvertent ingestion of blister pill packs: report of two cases diagnosed by MDCT with emphasis on maximal intensity and volume rendering reformations.

We report two cases of elderly patients presenting with life-threatening complications due to inadvertent accidental ingestion of blister pill packs (BPPs). The first patient presented with obstruction followed by anemia and finally perforation of the small bowel. The second presented with rapidly lethal mediastinitis due to a large perforation of the lower esophagus. The responsible BPPs were identified by multidetector computed tomography and the best result in their characterization was obtained through maximal intensity projections and volume rendering reformations.

Unusual vanishing interstitial lymphatic "pearls" in a patient presenting with extensive interstitial and mediastinal MDCT features of acute cardiogenic failure related to bradycardia and mitral regurgitation.

Thoracic multidetector computed tomography-MDCT-was simultaneously performed during emergency abdominal CT in a patient presenting with abdominal pain and acute cardiogenic edema related to sick sinus syndrome and mitral prolapse with regurgitation. A constellation of severe but completely reversible interstitial and mediastinal features was found comprising pleural effusions, diffuse alveolar ground glass, thickening of the bronchial walls and septal lines, hazy infiltration of the mediastinal fat, and enlarged lymphatic nodes. Multiple atypical hypodense nodular "pearls" were also found. These oval shape or fusiform pearls were distributed along the thickened septal lines and disappeared completely after treatment. The hypothesis of transient lymphatic ectasia or lakes is proposed for these never previously described abnormalities.

Extra-abdominal lumbar abscesses caused by retroperitoneal gastrointestinal perforations through the lumbar triangle of Petit: report of two cases diagnosed by CT.

Extra-abdominal abscesses of gastrointestinal origin developing within the lumbar subcutaneous tissues are extremely rare. We report two cases of retroperitoneal bowel perforation presenting spontaneously at admission with a lumbar abscess trespassing the lumbar triangle of Petit, a classical "locus of minus resistencia" of the posterior abdominal wall. The first case was caused by perforation of a retrocecal appendicitis--being concomitantly responsible of a necrotizing fasciitis of the thigh--and in the second case perforation was caused by left colonic diverticulitis. In both cases, the full diagnosis was made with abdominal CT. The patients were threatened by a two-step surgical approach comprising a direct posterior percutaneous drainage of the abscess followed by classical laparotomy.

Colonic Hemostatic Clip Causing Perforated Acute Appendicitis.

Teaching Point: The advantages of CT over other imaging techniques for the diagnosis of acute appendicitis in adults include the ability to identify foreign bodies that may be involved.

MDCT findings in primary amyloidosis of the greater omentum and mesentery: a case report.

Imaging findings of amyloid infiltration of the greater omentum, mesentery, and retroperitoneal spaces have only extremely rarely been reported in the radiological literature. This report illustrates the MDCT findings fortuitously found in a 70-year-old male presenting with a known latent myeloma.Extra abdominal deposits-axilla and cardiophrenic angles-were first fortuitously found during thoracic MDCT. Secondary abdominal MDCT revealed the extensive abdominal spread that consisted of very diffuse but asymptomatic pseudo carcinomatous hazy omental, mesenteric and-in a minder proportion-retroperitoneal deposits; these remained isolated without calcification, lymphadenopathy, ascites, or any sign of associated bowel wall thickening. A specific definite histologic diagnosis was made without laparotomy through a biopsy in the right axilla.

Ileocecal herniation through the foramen of Winslow: MDCT diagnosis.

We report a rare case of small bowel obstruction of a 45-year-old female which was caused by internal hernia of the terminal ileum and cecum through the foramen of Winslow. The patient presented to the emergency department with acute abdominal pain, distention, and nausea, suggesting an intestinal obstruction. The complete unambiguous preoperative diagnosis was achieved by a 64-row multi-detector computed tomography. This report enlightens the utility and performances of high-quality computed tomography multiplanar reconstructions combined with vascular volume rendering analysis for the diagnosis of internal hernia.

Small-bowel internal herniation through the falciform ligament: 64-row MDCT diagnosis.

We report a very rare case of internal hernia of the small bowel through a large congenital defect of the falciform ligament. A complete preoperative diagnosis was possible by 64-row multi-detector row computerized tomography. The identification of the characteristic anatomic features and landmarks of the obliterated umbilical vein-ligamentum teres-was the diagnostic key.

Massive Benign Pneumatosis Intestinalis.

Teaching point: CT may help distinguishing benign from life-threatening pneumatosis intestinalis.

Acute Volvulus of the Cecum.

Teaching Point: Abnormal embryological cecal fixation may lead to volvulus, which accounts for approximately 1 to 3 percent of all colic obstructions. A pack of suggestive CT features can make the diagnosis.

Intravesical Protrusion of a Pedunculated Colonic Polyp through a Sigmoido-Vesical Fistula Caused by Diverticulitis.

Teaching Point: Sigmoid diverticulitis may cause colo-vesical fistula from which intravesical protrusion of a pedunculated colonic polyp is an exceptional event that should not be regarded as a bladder cancer.

64-row MDCT review of anatomic features and variations of the normal greater omentum.

BACKGROUND: There are only few basic papers treating of the imaging features and anatomic variations of the normal greater omentum (GO). The goal of our study was to exploit the new major capabilities of 64-row MDCT-in terms of spatial resolution and crucial improvements in the quality of 2D and 3D reformatted images-to extensively review the in vivo anatomy, landmarks and variations of the normal GO a large cohort of patients. METHODS: The abdominal 64-row MDCT of a series of 111 patients (51 females and 60 males) were scrupulously retrospectively analysed to individually characterize the morphologic and anatomic features of the GO through multiplanar reconstructions, various methods of measure and selective volume rendering views. RESULTS: The GO was clearly identified, localized and characterized in all patients. The good delineation of the GO vessels, which predominantly have a vertical course, was the key of this analysis. Several individual and sex related anatomic variations were found. In females the left hemi-GO was found being statistically significantly longer than the right (P = 0.0053) but also longer than the male left hemi-GO (P < 0.0001). On the contrary, no statistically significant variation was found between the length of the left and right hemi-GO in males and between the length of the right hemi-GO in males and females. The average length of the entire GO also appeared sex-related being very statistically significantly longer in females than in males (P = 0.0002). In males the mean thickness of the GO (mtGO) was paralleling the increasing of the maximal thickness of the subcutaneous fat (mtSF). In females it remained rather independent from the increasing of the mtSF and, as a consequence, in obese and very obese females the increasing volume of the abdomen is caused preponderantly by the increasing amount of SF. In most males and females the mtGO followed the increasing of the amount of intraabdominal fat. Finally the projection of a less or more important portion of the GO into the pre-hepatic sub-phrenic space was an almost exclusive male feature found in 32% of males versus only 2% in females. CONCLUSION: Abdominal 64-row MDCT is able to perfectly delineate the anatomy and landmarks of the normal GO. Our study reveals several sex related anatomical variations. Knowledge of these anatomic variations may be helpful for a better understanding and diagnosis of various pathologic processes involving the GO including vascular, inflammatory and neoplastic diseases but also for surgical therapy planning including reconstructive surgery.

The Typical "Cracked Dry Mud" Ultrasound Pattern of Proliferative Myositis.

Teaching point: The typical "cracked dry mud" pattern on ultrasound may help avoiding biopsy for proliferative myositis which is a self-resolving benign process.