Gamna-Gandy bodies of the spleen: evaluation with MR imaging

A prevalence and molecular characterization of novel pathogenic strains of Macrococcus caseolyticus isolated from external wounds of donkeys in Khartoum State -Sudan

A pathogenic strain of Macrococcus caseolyticus (M. caseolyticus) was isolated from wounds infection during an investigation on donkeys in Khartoum State. (122) samples were collected from external wounds (head, abdomen, back and leg) during different seasons. One isolate (124B) was identified using whole-genome sequence analysis. RAST software identified 31 virulent genes of disease and defense, including methicillin-resistant genes, TatR family and ANT(4')-Ib. Plasmid rep22 was identified by PlasmidFindet-2.0 Server and a CRISPR. MILST-2.0 predicted many novel alleles. NCBI notated the genome as a novel M. caseolyticus strain (DaniaSudan). The MLST-tree-V1 revealed that DaniaSudan and KM0211a strains were interrelated. Strain DaniaSudan was resistant to ciprofloxacin, ceftazidime, erythromycin, oxacillin, clindamycin and kanamycin. Mice modeling showed bacteremia and many clinical signs (swelling, allergy, wounds, and hair loss). Enlargement, hyperemia, adhesions and abscesses were observed in many organs.Constructive conclusionThe prevalence of the strain was 4.73%, with significant differences between collection seasons and locations of wounds. A highly significant association between doses (105 CFU/ml, 102 CFU/ml, Intra-peritoneum and sub-cutaneous) and swelling, developing of allergy and loss of hair (p = 0.001, p = 0.000 and p = 0.005) respectively were seen.This result represents the first report of pathogenic strains of M. caseolyticus worldwide.

Iron-containing pathologies of the spleen: magnetic resonance imaging features with pathologic correlation

Systemic and non-systemic pathologies that involve iron deposition within the spleen have characteristic features on MRI due to the susceptibility properties of deposited iron, or hemosiderin. These lesions will have signal loss on longer echo sequences due to the T2* effect when evaluated with dual-echo gradient-echo sequences. The pathophysiology of systemic and localized iron sequestration disease processes can elucidate an underlying diagnosis based on these imaging features in conjunction with clinical information.

Noninvasive imaging assessment of portal hypertension

Portal hypertension (PH) is a spectrum of complications of chronic liver disease (CLD) and cirrhosis, with manifestations including ascites, gastroesophageal varices, splenomegaly, hypersplenism, hepatic hydrothorax, hepatorenal syndrome, hepatopulmonary syndrome and portopulmonary hypertension. PH can vary in severity and is diagnosed via invasive hepatic venous pressure gradient measurement (HVPG), which is considered the reference standard. Accurate diagnosis of PH and assessment of severity are highly relevant as patients with clinically significant portal hypertension (CSPH) are at higher risk for developing acute variceal bleeding and mortality. In this review, we discuss current and upcoming noninvasive imaging methods for diagnosis and assessment of severity of PH.

The many faces of cirrhosis

There are many different imaging features of cirrhosis, some of which are less commonly recognized. It is important that the radiologist is familiar with these features as cirrhosis can be first discovered on imaging performed for other indications, thus alerting the clinician for the need to screen for complications of cirrhosis and referral for potential treatment. This article reviews the various imaging findings of cirrhosis seen on cross-sectional imaging of the abdomen and pelvis.

Primary Angiosarcoma of the Spleen

The CT and MR findings in 2 patients with surgically proven splenic angiosarcoma are presented. Two distinctive radiologic and pathologic patterns were observed: total tumor replacement of the spleen with preservation of normal contour or multiple nodular masses in the spleen. The various findings on CT and MR imaging reflected the hemorrhagic nature of the lesions with increased iron content. MR imaging appeared to be superior to CT in demonstrating these features. In the case of focal lesions, radiologic differentiation from lymphoma or metastasis was impossible.

Spleen and Liver

In liver cirrhosis, the spleen is a source of nitric oxide which affects a hyperdynamic state typical of portal hypertension. It is generally accepted that pancytopenia results predominantly from the increased phagocytosis and destruction of hemocytes in splenic macrophages. In addition, liver fibrosis is amplified by migrated Th2 lymphocytes and transforming growth factor beta from the spleen. There is a possibility that increase of the spleen stiffness is the primary factor of idiopathic portal hypertension. Spleen stiffness is caused by bleeding, fibrosis, and calcareous deposits after increase in red pulp pressure due to venous congestion. In nonalcoholic steatohepatitis, macrophage activity in the spleen is upregulated. In addition, high levels of inflammatory cytokines are produced and T cell shows increased proliferation in the spleen. In autoimmune hepatitis model, CD4⁺ T cells are differentiated into follicular helper T cells (T_FH) in the spleen. T_FH cells promoted hypergammaglobulinemia and antinuclear antibodies production. T_FH cells migrate from the spleen to the liver, triggering induction of autoimmune hepatitis in this model. IgM-positive B cells localize in the CD21-positive lymph follicle in the spleen of primary biliary cholangitis. These findings prove that the spleen influences on the pathogenesis and severity of several kinds of liver disease.

Noninvasive diagnostic method for idiopathic portal hypertension based on measurements of liver and spleen stiffness by ARFI elastography

BACKGROUND

Acoustic radiation force impulse (ARFI) elastography is an ultrasound technique that is capable of measuring tissue stiffness noninvasively. It is difficult to differentiate idiopathic portal hypertension (IPH) from liver cirrhosis (LC) or chronic hepatitis (CH), and liver biopsy is essential. We investigated whether it would be possible to noninvasively diagnose IPH by measuring the stiffness of the liver and spleen by ARFI.

METHODS

The subjects were 17 IPH patients, 25 LC patients, 20 CH patients, and 20 normal controls (NC). We measured liver stiffness, spleen stiffness, and the spleen/liver stiffness ratio, and plotted ROC curves.

RESULTS

The median value of liver stiffness in the IPH group was lower than that in the LC group (p = 0.00077) and about the same as in the CH group (p = 0.79). The median value of spleen stiffness was highest in the IPH group (IPH vs. LC group, p = 0.003; IPH vs. CH group, p < 0.00001). The spleen/liver stiffness ratio was lower in the LC group and in the CH group, and higher in the IPH group (p < 0.001, respectively). When an ROC curve of spleen/liver stiffness ratios was plotted to differentiate between the IPH group and the combined group of patients with other liver diseases (LC + CH group), when a cutoff value of 1.71 was used, the AUROC was 0.933 sensitivity 0.941, specificity 0.800, and accuracy 0.839.

CONCLUSION

Measuring the spleen/liver stiffness ratio by ARFI made it possible to noninvasively, specifically, and accurately diagnose IPH.

Splenic siderotic nodules in patients with liver cirrhosis

The aim of this study was to investigate the interrelation between splenic siderotic nodules, hypersplenism and liver function in patients with liver cirrhosis. The splenic enhanced susceptibility-weighted angiography (ESWAN) and conventional magnetic resonance images of 33 patients with liver cirrhosis were retrospectively studied and the ESWAN images were graded. The distribution and prevalence of the image grades for patients with and without hypersplenism were evaluated. In addition, the splenic volume and the distribution of Child-Pugh and albumin scores were compared between patients with and without siderotic nodules, and the correlation between splenic volume and the ESWAN image grades were evaluated in the patients with siderotic nodules. The ESWAN images revealed splenic siderotic nodules in 24 patients. The distribution and prevalence of the ESWAN image grades were demonstrated to be significantly different (P<0.001) between patients with and without hypersplenism. Furthermore, significant differences were observed between patients with and without siderotic nodules with regard to splenic volume and the distribution of Child-Pugh and serum albumin scores (P<0.001). No significant correlation was demonstrated between splenic volume and the ESWAN image grades (P>0.05). In conclusion, a higher prevalence of splenic siderotic nodules (72.7%) was observed using the ESWAN sequence, in comparison with results from previous studies, obtained using the T1-spoiled gradient echo sequence. The presence of splenic siderotic nodules was consistent with the occurrence of hypersplenism and was interrelated with reserved liver function.

Gamna-Gandy bodies of the spleen detected with susceptibility weighted imaging: maybe a new potential non-invasive marker of esophageal varices

Background/Objectives

Portal hypertension (PH) is a clinical sequelae of liver cirrhosis, and bleeding from esophageal varices (EV) is a serious complication of PH with significant morbidity and mortality. The aims of this study were to assess the ability of 2D multislice breath-hold susceptibility weighted imaging (SWI) to detect Gamna-Gandy bodies (GGBs) in the spleens of patients with PH and to evaluate the potential role of GGB number as a non-invasive marker of PH and EV.

Materials and Methods

T1-, T2- and T2^*- weighted imaging and SWI were performed on 135 patients with PH and on 37 control individuals. Platelet counts were collected from all PH patients. Two radiologists analyzed all magnetic resonance imaging (MRI) data, and measured the portal vein diameter, splenic index (SI), and platelet count/spleen diameter ratio. The numbers of patients with GGBs in the spleen were determined, and the numbers of GGB were counted in the four MRI sequences in GGB-positive patients. The portal vein diameter, SI, platelet count, and platelet count/spleen diameter ratio of control individuals were compared with those of GGB-negative and GGB-positive patients on SWI images. The correlations among GGB numbers, the portal vein diameter, the SI, the platelet count, and the platelet count/spleen diameter ratio were analyzed.

Results

The GGB detection rate and the detected GGB number by using SWI were significantly greater than those by using T1-, T2-, and T2*- weighted images. The number of GGBs in the SWI images correlated positively with the portal vein diameter and SI and correlated negatively with the platelet count and platelet count/spleen diameter ratio.

Conclusion

SWI provided more accurate information of GGBs in patients with PH. The number of GGB may be a non-invasive predictor of improving the selection for endoscopic screening of PH patients at risk of EV.

Avaliação ultra-sonográfica de nódulos sideróticos esplênicos em pacientes esquistossomóticos com hipertensão portal

OBJETIVO: Medir a sensibilidade e a reprodutibilidade da ultra-sonografia na detecção de nódulos sideróticos esplênicos em pacientes esquistossomóticos, tendo a ressonância magnética como padrão de referência. MATERIAIS E MÉTODOS: Na primeira fase do trabalho, 21 pacientes portadores de esquistossomose na forma hepatoesplênica com diagnóstico de nódulos sideróticos à ressonância magnética foram submetidos a avaliação ultra-sonográfica para a determinação da sensibilidade do método. Na segunda fase, com o objetivo de avaliar a reprodutibilidade da ultra-sonografia na detecção e na quantificação de nódulos sideróticos (A: 1-5 nódulos; B: 6-20 nódulos; C: mais de 20 nódulos), outros 30 pacientes esquistossomóticos foram submetidos a avaliação ultra-sonográfica de forma cega e independente por dois observadores. A reprodutibilidade foi medida por meio da concordância entre os observadores e do teste kappa. RESULTADOS: A sensibilidade da ultra-sonografia foi de 95,2% (intervalo de confiança a 95% [77,3%; 99,2%]). A concordância entre ultra-sonografia e ressonância magnética para a detecção de nódulos sideróticos foi de 96,7% (intervalo de confiança a 95% [82,8%; 99,9%]). Para a classificação dos nódulos conforme a sua quantificação, o índice kappa demonstrou concordância interobservador substancial (kappa = 0,67). CONCLUSÃO: A ultra-sonografia é um método que apresenta elevada sensibilidade e boa precisão para a avaliação de nódulos sideróticos esplênicos.

Liver fat: effect of hepatic iron deposition on evaluation with opposed-phase MR imaging

PURPOSE

To retrospectively determine the effect of liver iron deposition on the evaluation of liver fat by using opposed-phase magnetic resonance (MR) imaging.

MATERIALS AND METHODS

Committee on Human Research approval was obtained, and compliance with HIPAA regulations was observed. Patient consent was waived by the committee. Thirty-eight patients with cirrhosis (30 men, eight women; mean age, 58 years; range, 34-76 years) who underwent abdominal MR imaging and had contemporaneous liver biopsy were retrospectively identified. Two radiologists independently quantified liver fat according to the relative loss of signal intensity and compared this loss on opposed-phase and in-phase T1-weighted gradient-echo images. Liver fat percentage and presence of iron deposition were independently recorded by a pathologist. Generalized linear models, which included a mixed-random effects model, were used to determine the effect of iron deposition on the Spearman correlation coefficient for relative signal intensity loss versus histopathologically determined fat percentage.

RESULTS

Liver iron deposition was found in 25 of 38 patients. Liver fat percentage (mean, 3%; range, 0%-25%) was identified histopathologically in 14 of 38 patients and in nine of 25 patients with iron deposition. For both readers, relative signal intensity loss at opposed-phase imaging was closely and significantly correlated (P < .05) with histopathologically determined liver fat percentage in patients without iron deposition (r = 0.7 for reader 1, r = 0.6 for reader 2), but no such correlation was found in patients with iron deposition (r = 0.1 for reader 1, r = -0.31 for reader 2; P > .05).

CONCLUSION

Signal intensity loss on in-phase images caused by the presence of liver iron is a potential pitfall in the determination of liver fat percentage at opposed-phase MR imaging in chronic liver disease.

MR imaging of the spleen: spectrum of abnormalities

The spleen has the same relationship to the circulatory system that the lymph nodes have to the lymphatic system. A wide range of diseases can affect the spleen. Pathologic conditions of the spleen can be classified into the following categories: congenital diseases (accessory spleen, polysplenia, and asplenia); trauma; inflammation (abscess, candidiasis, histoplasmosis, and sarcoidosis); vascular disorders (infarction, diseases affecting the splenic vasculature, and arteriovenous malformation); hematologic disorders (sickle cell disease and extramedullary hematopoiesis); benign tumors (cysts, hemangioma, diffuse hemangiomatosis of the spleen, and hamartoma); malignant tumors (sarcoma, lymphoma, and metastases); and other disease processes that affect the spleen diffusely (portal hypertension, Gaucher disease, and sickle cell disease) or focally (Gamna-Gandy nodules). New magnetic resonance (MR) imaging techniques have increased the role of MR imaging in detection and characterization of splenic diseases. MR imaging is an excellent tool for diagnosis and evaluation of focal lesions and pathologic conditions of the spleen.

Avaliação hepática e esplênica por ressonância magnética em pacientes portadores de esquistossomose mansônica crônica

OBJETIVO: Avaliar, qualitativa e quantitativamente, as alterações morfológicas hepáticas e esplênicas por ressonância magnética (RM) em pacientes portadores de esquistossomose mansônica crônica, e a reprodutibilidade do método na avaliação hepatoesplênica destes pacientes. MATERIAIS E MÉTODOS: Realizou-se estudo prospectivo em 28 pacientes esquistossomóticos submetidos à RM de abdome superior. Os exames foram realizados em equipamento com alto campo (1,5 T), utilizando-se bobina de corpo e bomba injetora para a administração do contraste endovenoso, e interpretados por dois examinadores independentes, que avaliaram a presença de alterações morfológicas hepáticas e esplênicas. A concordância interobservador e intra-observador foram medidas pelo teste kappa e pelo teste do coeficiente de correlação intraclasses. RESULTADOS: As variáveis qualitativas e quantitativas apresentaram boa concordância interobservador e intra-observador (kapa > 0,65 e r > 0,66, respectivamente). A maior concordância interobservador foi obtida para o diâmetro ântero-posterior do baço (r = 0,98). Os observadores identificaram redução do lobo hepático direito, aumento do lobo hepático esquerdo e caudado associado a esplenomegalia em quase todos os pacientes, e alargamento de fissuras, heterogeneidade do parênquima hepático, irregularidade de contornos, vasos periféricos hepáticos e fibrose periportal em mais de 82% dos pacientes. CONCLUSÃO: As alterações morfológicas hepáticas caracterizam-se pela redução do lobo direito e aumento dos lobos caudado e esquerdo, e as esplênicas, pela presença de esplenomegalia e nódulos sideróticos. A RM apresenta elevada reprodutibilidade na avaliação dessas alterações em pacientes com esquistossomose mansônica crônica.

Gamna-Gandy Bodies in Surgical Neuropathology Specimens: Observations and a Historical Note

Gamna-Gandy (G-G) bodies are classically defined as spheroidal yellow-brown foci consisting of dense fibrous tissue and collagenous fibers encrusted with iron pigments and calcium salts. These siderotic nodules were first described in the spleen early in the twentieth century and for a short time were considered to be caused by fungal infection due to the presence of unusual "bamboo-like and articulated" fibers in the lesions that vaguely mimicked mycelia forms. This notion was proven to be incorrect in the 1930s and G-G bodies are now considered to result from organization of small hemorrhages. Although originally reported in splenomegaly, G-G bodies are well-recognized findings in atrial myxomas where they form linear arrays of mineral-encrusted fibers, often at the edge of resolving hemorrhages. They rarely have been reported in lymph nodes, thymoma, thyroid adenoma, and renal cell carcinoma. Curiously, published examples of G-G bodies in central nervous system (CNS) neoplasms or vascular malformations have not appeared, despite the known tendency for bleeding, even recurrent episodes of bleeding, in several types of these lesions. Since 1999 I have accrued all the examples of G-G bodies that I have observed in my practice of surgical neuropathology. These cases are presented here and the historical aspects of the entity are reviewed.

Small echogenic foci in the ovaries: correlation with histologic findings

OBJECTIVE

The purpose of this study was to determine the histologic correlate of small echogenic foci in the ovary and to assess for any association with endometriosis or endosalpingiosis.

METHODS

Women planning to have a normal ovary surgically removed were scanned preoperatively with transvaginal sonography. If echogenic foci were present in either normal ovary on the preoperative scan, the removed ovary was scanned in a saline bath, and the surface was marked with india ink over an echogenic focus. Histologic sections were then obtained at the marked site.

RESULTS

Echogenic foci were detected in 23 ovaries of 16 women. Possible causes were found in 17 of the 23 ovaries: hemosiderin in 6 cases, calcification in 5 cases, hemosiderin and calcification in 2 cases, clusters of inclusion cysts in 2 cases, 1 of which also had hemosiderin, and dense cortical nodules in 2 cases. Histologic findings were benign in all cases except in 1 patient who had primary peritoneal carcinoma unrelated to the echogenic foci. One ovary in another patient had both endosalpingiosis and endometriosis. One other patient had endometriosis involving a fallopian tube but not the ovary. There were no other cases of endometriosis or endosalpingiosis.

CONCLUSIONS

Small echogenic foci in the ovaries are most frequently due to hemosiderin or calcification. A few small echogenic foci in the ovaries are associated with benign histologic changes and do not appear to be reliable indicators of endosalpingiosis or endometriosis.

Gamna-Gandy bodies of the spleen detected with MR imaging: a case report

We report a case of a female patient with portal hypertension due to liver cirrhosis. In this case, MR imaging revealed small siderotic nodules of the spleen, called Gamna-Gandy bodies. These lesions are found in patients with portal vein or splenic vein thrombosis, hemolytic anemia, leukemia, or lymphoma, patients receiving blood transfusions, acquired hemochromatosis, or paroxysmal nocturnal hemoglobinuria. There are only few reports in the literature about these siderotic nodules which are not very familiar. MR imaging seems to be the superior imaging method for detection of these lesions. It is important to consider Gamna-Gandy bodies in the differential diagnosis of portal hypertension and the other diseases mentioned above.

Hepatobiliary and pancreatic manifestations of cystic fibrosis: MR imaging appearances

Magnetic resonance (MR) imaging and MR cholangiopancreatography are useful, noninvasive techniques for the assessment of pancreatic and hepatobiliary complications in cystic fibrosis. Abnormalities of the pancreas in cystic fibrosis are typically characterized by fat deposition, which has increased signal intensity on T1-weighted MR images, and pancreatic fibrosis, which has low signal intensity on both T1- and T2-weighted images. Pancreatic cysts are a relatively common finding; these cysts are typically quite small but are well demonstrated at MR imaging and MR cholangiopancreatography. Pancreatic duct abnormalities are also occasionally seen. Hepatic manifestations range from hepatomegaly and diffuse fatty infiltration to severe cirrhosis with fibrotic change, regenerative nodules, and portal hypertension. Splenomegaly is often characterized by siderotic nodules that manifest as multiple focal areas of abnormal low signal intensity within the spleen. Biliary manifestations include cholelithiasis, stricturization, and narrowing or dilatation of intra- and extrahepatic bile ducts. Gallbladder abnormalities including microgallbladder are also readily demonstrated. MR cholangiopancreatography can be used to help determine the presence and severity of biliary complications without resorting to more invasive procedures and, in conjunction with MR imaging, may prove useful in the assessment of patients with cystic fibrosis who present with abdominal symptoms that suggest hepatobiliary involvement.

CT and MRI of diffuse liver disease

CT and MRI contribute important information to the clinical evaluation of diffuse liver disease. In some cases, these modalities can establish a diagnosis that was not ascertained histologically, which is often the case when sampling errors prevent a definitive tissue diagnosis. Characteristic alterations of liver attenuation on CT, signal changes on MRI, and morphological changes appreciated with both modalities can be used to diagnose fatty infiltration, some parenchymal deposition diseases, and cirrhosis. Furthermore, hepatocellular disease can be confirmed in the setting of indeterminate clinical and laboratory findings. Significant overlap in the imaging findings of this wide range of disorders continues to limit specificity; however, at a minimum, these techniques provide a rapid means to a noninvasive evaluation that often guides clinical decisions. Faster scanning techniques available with CT and MRI may provide additional information by assessing contrast dynamics. This review of CT and MRI in diffuse liver disease considers the diagnostic utility and clinical implications of these modalities. Pathological findings relevant to imaging considerations are discussed.

Hepatic vascular diseases: CT and MRI

Continued development of CT and MRI techniques has allowed these modalities to detect most hepatic vascular diseases, often obviating more invasive tests. In this article, the techniques for hepatic vascular diagnosis are reviewed, with emphasis on spiral CT and two-dimensional MRI techniques, and then the major vascular diseases on which these two modalities have a significant diagnosing impact are considered.

Multiple reflective channels in the spleen: a sonographic sign of portal hypertension

We consistently observed small "reflective channels" (RCs) in the splenic parenchyma in patients with portal hypertension (PHT). The purpose of this study was to investigate the frequency of this sign in PHT and in splenic disorders unrelated to PHT compared to normal controls. The significance of this sign in the diagnosis of PHT and in differentiating PHT splenomegalies from others was also assessed. A total of 337 patients underwent sonographic examination of the spleen: 147 normal, 75 non-PHT splenic pathologies, and 115 with PHT. The RCs were scored from grade 0 to 3 by counting the number in an area of 12 mm2 in the splenic parenchyma. Of 222 normal and non-PHT spleens, 174 (78%) showed grade 0, 44 (20%) grade 1, four grade 2 (1%), and none showed grade 3 RCs. Of 115 PHT cases, 17 showed grade 0, 25 grade 1, 44 grade 2, and 29 showed grade 3 RCs. The sensitivity of this sign was 0.85 with a specificity of 0.77 and an accuracy of 0.80 in detecting PHT (p < 0.001). The interobserver and intraobserver variation for grading was insignificant (p > 0.1). The RCs could be explained by periarterial fibrosis and dilatation of venous sinuses with increased collagen in their walls, which is known to occur in PHT. The vascular nature on ultrasound (US) was confirmed by the presence of flow on color Doppler. This sign is readily differentiated from the calcifications of tuberculosis, histoplasmosis, sickle cell infarcts, and phleboliths; it serves as a useful aid in diagnosing and differentiating PHT splenomegaly from non-PHT splenomegaly.

Nodular sarcoidosis of the liver and spleen: appearance on MR images

Small nodular lesions in the liver and spleen have been reported as an infrequent manifestation of sarcoidosis. Five patients with this appearance on either dynamic contrast material-enhanced computed tomographic (CT) or ultrasound scans underwent magnetic resonance (MR) imaging with and without dynamic gadolinium enhancement. The lesions were relatively uniform in size, ranging from 0.5 to 1.5 cm. On CT scans, they were hypoattenuating relative to surrounding parenchyma. On MR images, the lesions were hypointense relative to background parenchyma with all sequences. No substantial enhancement was observed in the lesions, although lesion conspicuity decreased over time on serial postcontrast images. Lesion conspicuity was greatest on either T2-weighted fat-suppressed (T2FS) images or early-phase dynamic contrast-enhanced images. Abdominal adenopathy was seen in three of the five patients and was hyperintense relative to liver on T2FS images in two and intermediate in intensity in one patient.

MR of the kidneys, liver, and spleen in paroxysmal nocturnal hemoglobinuria

The magnetic resonance (MR) findings in the liver, kidneys, and spleen in eight patients with paroxysmal nocturnal hemoglobinuria (PNH) were retrospectively reviewed to determine whether characteristic features could be demonstrated. Eight patients underwent abdominal MR examinations by gradient echo sequences (seven patients), spin-echo sequences (seven patients), and inversion recovery (one patient). Signal intensities of the kidneys, liver, and spleen were visually evaluated. Autopsy and liver biopsy correlation were available in one case each. Renal signal intensity was decreased in all eight patients by either gradient-echo or T2-weighted sequences and in the single inversion recovery sequence. Hepatic signal intensity was decreased in three of eight patients on spin- and gradient-echo images. Splenic signal intensity was decreased in three of eight patients on spin- and gradient-echo images, and in two of these was manifest as focal low signal spots (Gamna-Gandy bodies). While the signal intensity in the renal cortex is typically decreased in patients with PNH, signal intensities in the liver and spleen are variable. Low signal intensity in the kidneys is due to hemosiderin deposition resulting from intravascular hemolysis, whereas low signal intensity in the liver or spleen may be due to either transfusion siderosis, or as a consequence of hepatic or portal venous thrombosis.

Cirrhosis: multiobserver analysis of hepatic MR imaging findings in a heterogeneous population

To investigate the magnetic resonance (MR) imaging findings of hepatic cirrhosis and the potential of MR imaging in differentiating cirrhosis from other hepatic abnormalities, three observers with different levels of expertise in MR imaging (specialist, experienced radiologist, and novice with special training) reviewed hepatic MR imaging examinations of 52 patients with biopsy-proved presence (n = 29) or absence (n = 23) of cirrhosis. All examinations included motion-compensated T1-weighted, T2-weighted, and flow-sensitive gradient-echo images. For all three observers, linear signal irregularity was more accurate than other findings. For the final diagnosis of cirrhosis, the specialist was most sensitive (76% at high threshold, 97% at low threshold), followed by the novice with special training (31% and 79%, respectively). Specificity was 100% for all observers at high threshold and 78%, 96%, and 87% for expert, experienced, and trained novice observers, respectively, at low threshold. Sensitivity did not vary regardless of severity of fibrosis, as determined independently by a hepatopathologist. MR imaging has the potential of offering a comprehensive noninvasive evaluation of patients with suspected cirrhosis, but considerable expertise is required at present.

Detection of acute and treated lesions of hepatosplenic candidiasis: comparison of dynamic contrast-enhanced CT and MR imaging

Dynamic contrast-enhanced computed tomography (CT) was compared with 1.5-T magnetic resonance (MR) imaging with FLASH (fast low-angle shot), gadolinium-enhanced FLASH (Gd-FLASH), and T2-weighted fat-suppression (T2FS) sequences in 11 patients with hematologic malignancies, five with biopsy-confirmed hepatosplenic candidiasis treated with antifungal chemotherapy and six with a clinical history suggestive of acute hepatosplenic candidiasis. CT and MR images were separately interpreted in a prospective fashion. MR imaging showed lesions compatible with candidiasis in the liver in six patients, the spleen in five, and the kidneys in one. CT showed candidiasis-compatible lesions in the liver in three patients and the spleen in one; no renal lesions were shown. Differences between acute and treated candidal lesions were observed. Gd-FLASH images showed the most liver lesions (n = 106), followed by FLASH (n = 85), T2FS (n = 20), and CT (n = 18). MR imaging performed better than CT in distinguishing candidal hepatic lesions from recurrent lymphoblastic lymphoma in one patient and from hepatic infarcts in another. The results suggest that MR imaging may be superior to CT in detecting lesions of hepatosplenic candidiasis.