OVARIAN VEIN REFLUX WITH PELVIC VARICES

Coronal thick slab MIP images showing
dilated left gonadal vein reaching the renal vein.

Coronal thick slab MIP images showing unilateral pelvic varices on left side.

Volume rendered images(posterior view) showing
engorged left gonadal vein and ipsilateral pelvic varices.

 

·        In grade I, retrograde flow remained in the left ovarian vein, not reaching the parauterine veins.

·        In grade II, the retrograde flow advanced into the ipsilateral parauterine veins and no farther.

·        Finally, in grade III, the retrograde flow crossed the midline passing through the uterus from the left into the right parauterine plexus.

·        The flow-pathway was assessed from the level of the kidneys to the pelvic floor.

Causes :- 

·        Dilated and tortuous ovarian veins secondary to retrograde flow through incompetent valves

·        Obstructing anatomic anomalies

§  Retroaortic left renal vein

§  Left ovarian vein congestion due to compression of the left renal vein by the superior mesenteric artery (nutcracker phenomenon)

§  Right common iliac vein compression

§  Secondary congestion can be seen in various disorders including:

·        Valvular incompetence

·        Portal hypertension

·        Acquired inferior vena cava syndrome

 Reference : Reflux in the Left Ovarian Vein: Analysis of MDCT Findings in Asymptomatic Women, AJR November 2004 vol. 183 no. 5 1411-1415.

PARTIAL MIDGUT MALROTATION

Coronal post contrast CT section through pancreas showing
absent 3rd part of duodenum beneath the pancreas.

Axial post contrast CT section through kidneys showing clumped duodenum infero medial to pancreas with antero posterior relation of superior mesenteric vessels.
 

Intestinal malrotation can be broadly defined as any deviation from the normal 270° counterclockwise rotation of the midgut during embryologic development.

· Malrotation results not only in the malposition of the bowel but also in the malfixation of the mesentery.

· The normally broad mesenteric attachment is shortened to a narrow pedicle that predisposes the patient to the complication of midgut volvulus.

· Internal hernia related to abnormal peritoneal fibrous bands (of Ladd) that attach to the right colon is another complication of malrotation seen in adults.

· Conventional radiography is neither sensitive nor specific for malrotation, although right-sided jejunal markings and the absence of a stool-filled colon in the right lower quadrant may be suggestive of this finding.

· The upper gastrointestinal barium series remains accurate for detection, and the rules familiar to pediatric radiology also apply for adults—that is, the duodenal—jejunal junction fails to cross the midline and lies below the level of the duodenal bulb.

· An abnormal junction in an adult should not be dismissed as a normal variant.

· Contrast enema examination usually shows malposition of the right colon, but the cecum may assume a normal location in up to 20% of patients.

· The contrast enema findings are also nonspecific because cecal location can be variable without malrotation.

· Many cases of quiescent malrotation in adults are currently being detected on cross-sectional imaging performed for various unrelated reasons.

· CT not only shows the intestinal malpositioning seen on barium studies but also depicts associated extraintestinal findings not evident on conventional examinations. For example, deviation from the normal relationship between the SMA and SMV is a useful indicator of malrotation.

· In most patients with quiescent malrotation, the SMA and SMV will assume a vertical relationship or show left—right inversion.

· Analogous findings can be seen on sonography.

· Abnormalities of SMA—SMV orientation are not entirely diagnostic, however, because some patients with malrotation will have a normal relationship, and a vertical or inverted relationship can also be seen in patients without malrotation.

· Therefore, isolated detection of such an abnormality is not sufficient for diagnosis but should warrant closer examination of the bowel.

· Finally, inspection of the pancreas in malrotation will reveal underdevelopment or absence of the uncinate process.

· Acute complications of malrotation:

1. Midgut volvulus

2. Internal hernia

· Regardless of patient age, surgical treatment of quiescent malrotation should be considered because surgery remains the only real safeguard against complications.

Reference : Intestinal Malrotation in Adolescents and Adults: Spectrum of Clinical and Imaging Features, AJR December 2002 vol. 179 no. 6 1429-1435.



 

KARTAGENER'S SYNDROME

10 yrs old boy with recurrent respiratory infections

 

Axial CT sections of chest in lung window show dextrocardia with dense cystic bronchiectasis involving middle lobe and lingula. Multiple infiltrates in bilateral lower lobes (not shown here).

Coronal reformatted images showing the same findings.

Axial CT section through the upper abdomen showed inversion of abdominal organs also
suggestive of complete situs inversus.

KARTAGENER'S syndrome

Findings:

The chest radiograph demonstrates dextrocardia with the stomach bubble and aortic arch on the right side. The findings represent situs inversus totalis. The patient has marked peribronchial thickening and a focal area of atelectasis in the left lung. Close inspection of the lung markings demonstrated tubular lucencies indicating bronchiectasis in this patient with known KARTAGENER'S SYNDROME.

This syndrome consists of a classic triad of:

• Sinusitis
• Bronchiectasis
• Situs inversus totalis

Also known as:

• Ciliary dyskinesia
• Immotile cilia syndrome

Clinical manifestations:

• Chronic cough
• Recurrent respiratory infections
• Sinusitis
• Otitis media
• Reduced fertility in males

The clinical manifestations are directly related to abnormal ciliary structure and/or function. Furthermore, situs inversus totalis occurs in approximately half of patients with Kartagener's syndrome, with the remainder having normal situs. This implicates the role of ciliary function in the early positioning of internal organs in the developing fetus. Without normal ciliary functioning, there is random occurrence of normal and reversed situs. Therefore, although the classic triad includes situs inversus, the syndrome includes those patients with normal situs.

Differential diagnosis:

The presence of airway disease and recurrent pulmonary and sinus infections may resemble the clinical and radiographic appearances of cystic fibrosis. Also, immunodeficiency states may present in a similar manner. The correct diagnosis is usually first recognized by the presence of situs inversus in a patient with chronic respiratory symptoms, and can be confirmed by biopsy of nasal cilia.

 

CYSTIC HYGROMA WITH NON IMMUNE FETAL HYDROPS

14 WEEKS GESTATION FOR NT SCAN

Diffuse subcutaneous edema of fetal thorax and abdomen with mild bilateral pleural effusion

Large cystic fluid collection in the nape of neck extending to both sides with few internal septations and diffuse subcutaneous edema of fetal cranium

·        Nuchal cystic hygromas are characterized by single or multiple congenital cysts of the lymphatic system most commonly found within the soft tissues of the neck.

·        The frequency is one in 875 spontaneous abortions.

·        Nuchal cystic hygromas are the clinical consequence of a delay in  development or absence of the communications that normally develop between the jugular lymph sacs and the internal jugular veins at approximately 40 days gestation.

·        The obstructed jugular lymph sacs dilate along the paths of least resistance into the posterior and lateral cervical areas.

·        Late communication of the sacs with the internal jugular vein may be manifest by redundancy of the posterior nuchal skin, neck webbing, and elevation and anterior rotation of the ears.

·        Complete lymphatic obstruction may be associated with nonimmune fetal hydrops, which is frequently fatal.

·        About 78% of patients with cystic hygroma are chromosomally abnormal; 58% have a karyotype associated with Turner syndrome phenotype; while autosomal trisomies and various structural abnormalities made up the remaining 20%.

·        The most common associated structural malformations are cardiac abnormalities.

·        Even among the 22% of fetuses with normal chromosomes, various physical anomalies are present.

·        Other syndromes associated with cystic hygromas are Noonan syndrome (autosomal dominant), Pena-Shokeir syndrome, Down syndrome, Robert’s syndrome (autosomal recessive) and multiple pterigium syndrome (autosomalrecessive, X-linked).

Ultrasonographic findings

·        The fetus presents with large bilateral cystic areas, termed cystic hygromas develop within the skin in the posterolateral aspect of the neck.

·        They may grow so large that they lie adjacent to each other.

·        It then appears that there is a cystic mass arising from the back of the neck with one to three septa in the center.

·        The skin thickening is most pronounced in the upper torso and cranium.

·        Hydrops occurs in more severe cases with large pleural effusions, pericardial effusions and ascites.

·        Amniotic fluid is often reduced.

·        Placenta is normal or thickened with hydrops.

·        Differential diagnosis is encephalocele or meningocele (the mass is posterior and is a single mass. It is associated with a cranial defect) and unfused amniotic membrane.

Reference : Antenatal Diagnosis and Management of Nuchal Cystic Hygroma: A Case Report in the Yaounde Central Maternity, Cameroon; Clinics in Mother and Child Health; Vol. 8 (2011).

LEIGH'S DISEASE

6 months old child with history of seizures. No history of hypoxic injury.




Axial T1 wt images show
homogenous hypointensity in bilateral caudate nuclei and anteromedial thalami.



Axial T2 wt images show homogenous hyperintensity in bilateral caudate nuclei,
lentiform nuclei, antero medial thalami, cerebral peduncles and periaqueductal gray matter.



All the above mentioned areas show restricted diffusion

·        Leigh disease (subacute necrotizing encephalomyelopathy) is a mitochondrial disease that results from a disorder in the respiratory chain production of adenosine triphosphate.

·        Inherited, progressive, neurodegenerative disease of infancy or early childhood with variable course and prognosis.

·        Clinical manifestations can be highly variable, affecting children and (rarely) young adults and typically causing central hypotonia, developmental regression or arrest, ophthalmoplegia, respiratory and bulbar dysfunction, and ataxia.

·        Characteristic pathologic abnormalities include microcystic cavitation, vascular proliferation, neuronal loss, and demyelination of the midbrain, basal ganglia, and cerebellar dentate nuclei and, occasionally, of the cerebral white matter.

·        MR imaging findings include symmetric areas of T2 prolongation in the basal ganglia, periaqueductal region, and cerebral peduncles, with putaminal involvement being a consistent feature.

·        The cerebral white matter is rarely affected. Enhancement may be seen at MR imaging and may correspond to the onset of acute necrosis

·        When Leigh disease is suspected, MR spectroscopy (best performed with long echo times) may reveal the presence of abnormally high lactate levels in the basal ganglia, which together with elevated serum and CSF lactate levels supports the diagnosis.

References :

1.     Leukodystrophy in Children: A Pictorial Review of MR Imaging Features,  May 2002 RadioGraphics, 22, 461-476

2.     Differential Diagnosis for Bilateral Abnormalities of the Basal Ganglia and Thalamus, January 2011 RadioGraphics, 31, 5-30

PERSISTANT OCCIPITAL SINUSES

Abnormal sinuses seen originating from torcula heterophili and coursing posterolaterally.

The sinuses are joining the internal jugular veins bilaterally.

·        Occipital sinuses usually communicate cranially at the torcular Herophili and caudally at the foramen magnum, where a multitude of variations may exist.

·        Occipital sinuses have been reported in up to 10% of normal subjects and may be associated with atretic transverse/sigmoid sinus segments and internal jugular vein. Correlation with CT may bolster confident diagnosis by demonstrating a smaller caliber sigmoid sinus groove and/or jugular foramen.

·        Occipital venous network is believed to regress once most of the venous flow passes through the major dural sinuses when children assume the upright position.

·        Accidental discovery of a persistent occipital sinus during posterior fossa surgery can result in catastrophic hemorrhage and/or occlusion of the occipital sinus that may lead to venous thrombosis/infarction.

OS ACROMIALE

UNFUSED ACCESSORY OSSIFICATION CENTRE OF ACROMION OF SCAPULA

 

 

There are normally 3 acromial ossification centers that fuse between 22 and 25 years of age.

An os acromiale results from the failure of 1 of these centers to fuse.

The anterior ossification center is termed the pre-acromion, the middle is the meso-acromion, and the posterior is the meta-acromion.

The basi-acromion forms the point of attachment of these 3 ossification centers to the scapula.

A number of subtypes of os acromiale have been described.

The most common variant is nonfusion between the meso- and meta-acromion.

The prevalence of os acromiale in radiographic and anatomic studies ranges between 1% and 15%.

An os acromiale can contribute to shoulder impingement symptoms.

Contraction of the deltoid muscle may pull the os acromiale downward, causing it to impinge on the rotator cuff.

Abnormal motion may lead to an osteophytic spur at the pseudarthrosis, which may also impinge on the cuff.

The diagnosis of os acromiale may be made on axillary projection radiographs, computed tomography (CT) or magnetic resonance imaging (MRI).

MRI may show marrow edema and degenerative changes at a pseudarthrosis.

SPLENIC ABSCESS

Axial T1 FS image showing large relatively thick walled fluid collection with debris and air pockets. Note the air fluid level anteriorly

Sagittal T2 Wt image showing the abscess with airfluid level anteriorly- suggests pyogenic abscess.



Axial DWI image showing mild restriction within the abscess.



·        The rarity of primary splenic abscesses is probably related to splenic phagocytic immune functions.

·        A splenic abscess may be bacterial, fungal, or granulomatous.

·        In infants and children, splenic abscesses occur most frequently in immunocompromised patients.

·        Abscesses may be single or multiple.

·        With fungal infections in an immunocompromised patient, abscesses are typically multiple.

·        Pyogenic abscesses can be secondary to underlying sepsis or spread by hematogenous seeding.

·        Amebic dysentery, otitis media, mastoiditis, peritonsillar abscess, cutaneous infection, pneumonia, empyema, appendicitis, osteomyelitis, and intravenous drug abuse are all risk factors.

·        Patients with hemoglobinopathies are also at risk for splenic abscess formation secondary to infarction and necrosis as well as functional asplenia.

·        Pyogenic abscesses manifest as ill-defined, hypoechoic lesions at US. Debris and internal septations may be present. In rare cases, gas bubbles may be seen.

·        If present, intralesional gas is pathognomonic for pyogenic infection.

·        At CT, pyogenic abscesses typically manifest as single, irregularly marginated lesions with low attenuation. Rim enhancement can be seen on contrast enhanced scans.

·        Fungal abscesses are small lesions, typically only a few millimeters in diameter.

·        The most common infecting organisms are Candida albicans, Aspergillus fumigatus, and Cryptococcus neoformans.

·        M tuberculosis, M avium intracellulare, and P carinii infection can have similar appearances.

·        Fungal abscesses have a variable appearance at US.

·        Typically, they manifest as rounded, hypoechoic lesions with a central area of increased echogenicity, creating a “target” or “bull's-eye” appearance. These findings correspond to fibrotic tissue surrounding a central inflammatory core at histopathologic analysis.

·        The “wheel-in-a-wheel” appearance is seen when the central hyperechoic portion becomes necrotic and hypoechoic.

·        Hepatosplenomegaly is usually associated with fungal abscesses. CT typically demonstrates multiple small, low-attenuation lesions. The lesions may be missed unless intravenously administered contrast material is used.

·        Reference: A Pattern-oriented Approach to Splenic Imaging in Infants and Children, November 1999 RadioGraphics, 19, 1465-1485.