Helical CT In Patients Research Articles

Small hepatic lesions found on single‐phase helical CT in patients with malignancy: Diagnostic capability of breath‐hold, multisection fluid‐attenuated inversion‐recovery (FLAIR) MR imaging using a half‐fourier acquisition single‐shot turbo spin‐echo (HASTE) sequence

To evaluate the diagnostic capability of breath-hold, multisection fluid-attenuated inversion-recovery (FLAIR) imaging using a half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence in combination with T2-weighted fast spin-echo (FSE) magnetic resonance (MR) sequences for small hepatic lesions found on CT in patients with malignancy. This study included 48 patients with extrahepatic malignancy who underwent both CT and MR examinations. There were a total of 112 small hepatic lesions (73 cysts and 39 liver metastases, <2 cm in diameter) that showed low attenuation on enhanced CT. Three radiologists independently reviewed the CT and MR (FLAIR-HASTE and T2-weighted FSE) images and assigned a confidence level to their evaluation (cyst or metastasis) on a five-point scale. All three reviewers were significantly better able (P < 0.05) to differentiate small hepatic cyst from liver metastasis with combined FLAIR-HASTE and T2-weighted FSE images (Az values = 0.997-0.999) than with CT (0.917-0.932). The mean values of sensitivity, specificity, and accuracy were significantly higher (P < 0.001) for T2-weighted FSE with FLAIR-HASTE (96.6%, 96.8%, and 96.7%, respectively) than for CT (76.9%, 61.6%, and 67.3%, respectively). A confident diagnosis was rendered in 12 of 112 lesions (10.7%) on the basis of CT, and this rate increased to 83 of 112 (74.1%) on the basis of T2-weighted FSE and FLAIR-HASTE imaging. FLAIR-HASTE is considered to be an effective sequence for differentiating hepatic cysts from liver metastases without the use of a contrast agent. With FLAIR-HASTE one can confidently diagnose small hepatic lesions found on CT in patients with a malignancy.

The value of drip infusion cholangiography using multidetector-row helical CT in patients with choledocholithiasis

The purposes of this study were to investigate the feasibility of drip infusion cholangiography computed tomography (CTCh) for choledocholithiasis and to compare the detection of the stone on CTCh with that of MR cholangiopancreatography (MRCP). CTCh examinations were performed after infusion of intravenous biliary contrast material (iotroxic acid meglumine, 100 ml) for patients with suspected biliary diseases and were reconstructed to maximum intensity projection (MIP) and multiplanar reformation (MPR). Of 432 patients who underwent CTCh, we identified 15 who underwent surgery or cholangioscopic removal for choledocholithiasis and 32 patients who underwent cholecystectomy due to cholecystolithiasis. Their MRCP images were compared with the CTCh images. The sensitivity and specificity of CTCh for detecting choledochal stones were 87% and 96% whereas those of MRCP were 80% and 88%. The sensitivity and specificity of CTCh for detecting gallstones were 78% and 100% whereas those of MRCP were 94% and 88%. CTCh allowed high sensitivity and specificity for detecting choledochal stones but diminished the detection for cholecystolithiasis compared with MRCP.

The value of drip infusion cholangiography using multidetector-row helical CT in patients with choledocholithiasis

The purposes of this study were to investigate the feasibility of drip infusion cholangiography computed tomography (CTCh) for choledocholithiasis and to compare the detection of the stone on CTCh with that of MR cholangiopancreatography (MRCP). CTCh examinations were performed after infusion of intravenous biliary contrast material (iotroxic acid meglumine, 100 ml) for patients with suspected biliary diseases and were reconstructed to maximum intensity projection (MIP) and multiplanar reformation (MPR). Of 432 patients who underwent CTCh, we identified 15 who underwent surgery or cholangioscopic removal for choledocholithiasis and 32 patients who underwent cholecystectomy due to cholecystolithiasis. Their MRCP images were compared with the CTCh images. The sensitivity and specificity of CTCh for detecting choledochal stones were 87% and 96% whereas those of MRCP were 80% and 88%. The sensitivity and specificity of CTCh for detecting gallstones were 78% and 100% whereas those of MRCP were 94% and 88%. CTCh allowed high sensitivity and specificity for detecting choledochal stones but diminished the detection for cholecystolithiasis compared with MRCP.

Helical CT Evaluation of Acute Right Lower Quadrant Pain: Part I, Common Mimics of Appendicitis

The purpose of our pictorial essay is to present common mimics of appendicitis as noted on helical CT in patients with right lower quadrant pain and to highlight the features that provide clues to the diagnosis. Recognition of the findings of common diseases that simulate acute appendicitis on helical CT, along with features that help to differentiate these entities from appendicitis, is important in establishing a correct diagnosis and in guiding appropriate therapy.

Mammary ductoscopy by helical CT: -Initial experience-

An attempt was made to visualize minute intraductal lesions using helical CT in patients with abnormal nipple discharge. Galactography was performed, immediately followed by CT (ductal CT examination). Based on the image data obtained, ductal images were constructed on a workstation using a Pegasus viewer (ductal CT imaging). Since no criteria for diagnosis by this method are available, ductal CT images were diagnosed by reference to the known ductal fiberscopic findings. Ductal CT examination was performed in 10 cases, in 9 of whom ductal CT images were successfully constructed. Pathological examination was performed in 8 cases. It was possible to observe the structure of the luminal surface on the constructed ductoscopic images from all directions, but the color tone or the presence or absence of hemorrhage could not be observed. In the examination for abnormal nipple discharge, ductal CT examination was useful for intraductal observation. Currently, it is a method that allows for observation of the most minute intraductal lesions. However, some issues still remain unresolved. The results of this study suggest that further studies with more cases hold the promise of making ductal CT imaging a useful examination method.

1718: Unenhanced Helical CT in Patients with Acute Flank Pain: Is it Always a Stone that Explains this Symptom?

1718: Unenhanced Helical CT in Patients with Acute Flank Pain: Is it Always a Stone that Explains this Symptom?

Mammary Ductoscopy by Helical CT: -Initial Experience-

Background: An attempt was made to visualize minute intraductal lesions using helical CT in patients with abnormal nipple discharge.Methods: Galactography was performed, immediately followed by CT (ductal CT examination). Based on the image data obtained, ductal images were constructed on a workstation using a Pegasus viewer (ductal CT imaging). Since no criteria for diagnosis by this method are available, ductal CT images were diagnosed by reference to the known ductal fiberscopic findings.Results: Ductal CT examination was performed in 10 cases, in 9 of whom ductal CT images were successfully constructed. Pathological examination was performed in 8 cases. It was possible to observe the structure of the luminal surface on the constructed ductoscopic images from all directions, but the color tone or the presence or absence of hemorrhage could not be observed.Conclusions: In the examination for abnormal nipple discharge, ductal CT examination was useful for intraductal observation. Currently, it is a method that allows for observation of the most minute intraductal lesions. However, some issues still remain unresolved. The results of this study suggest that further studies with more cases hold the promise of making ductal CT imaging a useful examination method.

Diagnostic value of attenuation measurements of the kidney on unenhanced helical CT of obstructive ureterolithiasis.

The objective of this study was to assess the diagnostic value of attenuation measurements of the kidney on unenhanced helical CT in patients with obstructive ureterolithiasis. Consecutive unenhanced helical CT scans of patients referred for acute unilateral renal colic were retrospectively reviewed. Patients with CT evidence of other urinary system diseases were excluded. Included scans (n = 145) were assessed for ureteral stone and secondary signs of obstruction such as unilateral collecting system or ureteral dilatation, perinephric stranding, and periureteral edema. Renal attenuation in Hounsfield units was measured in the upper, middle, and lower portions of the parenchyma, and a mean value was determined for each kidney. Ureteral stones were present in 76 patients. Renal attenuation on the side with lithiasis was lower than on the opposite kidney: 27.2 +/- 3.9 H vs 32.6 +/- 3.4 H (p < 0.001). Attenuation differences between kidneys were higher for patients with ureterolithiasis: 5.4 +/- 3.2 H (range, -3.3 to 13.0 H) versus 1.2 +/- 1.0 H (range, 0-4.7 H) (p < 0.001). An attenuation difference between kidneys greater than or equal to 5.0 H had 61% sensitivity, 100% specificity, 100% positive predictive value, 69% negative predictive value, and 79% accuracy for diagnosis of ureteral lithiasis. Attenuation difference between kidneys greater than or equal to 5.0 H was a valuable sign and had diagnostic performance similar to other secondary signs of obstructive ureterolithiasis. Furthermore, attenuation difference had the advantage of being an objective, measurement-based indicator.

Usefulness of Unenhanced Helical CT in Patients with Suspected Ureteral Colic

Purpose: To determine the usefulness of unenhanced helical CT in patients with suspected renal colic. Materials and Methods: One hundred and fourteen patients with suspected ureteral colic, referred by physicians, underwent unenhanced helical CT. Two radiologists prospectively interpreted the results, determining the presence or absence of ureter stone and other diseases that arise outside the urinary tract. In cases of ureteral stone, we retrospectively sought secondary signs of hydronephrosis, perinephric fat stranding, thickening of renal fascia, renal enlargement, and the tissue rim sign. Results: Among the 114 patients, 57 were confirmed as having ureter stones. Unenhanced helical CT depicted 57 of 58 stones in 57 patients, producing one false-negative and one false-positive result. Overall, the results showed 98% sensitivity, 95% specificity, 98% positive predictive value, 95% negative predictive value, and 97% accuracy. The frequencies of secondary signs were as follows: hydronephrosis, 95% (54/57); perinephric fat stranding, 81% (46/57); thickening of renal fascia, 77% (44/57); renal enlargement, 65% (37/57); and the tissue rim sign 72% (21/29). In 20 patients, the diagnoses were not related to stone disease and included one falsenegative diagnosis of pyonephrosis. Conclusion: Unenhanced helical CT provides information which is valuable in the accurate diagnosis of ureteral stone as well as other diseases that arise outside the urinary tract in patients with suspected renal colic.

Using contrast-enhanced helical CT to visualize arterial extravasation after blunt abdominal trauma: incidence and organ distribution.

We evaluated the incidence and organ distribution of arterial extravasation identified using contrast-enhanced helical CT in patients who had sustained abdominal visceral injuries and pelvic fractures after blunt trauma. Five hundred sixty-five consecutive patients from four level I trauma centers who had CT scans showing abdominal visceral injuries or pelvic fractures were included in this series. The presence or absence of arterial extravasation, as well as the anatomic sites of arterial extravasation, was noted. We obtained clinical follow-up data, including surgical or angiographic findings. In our series, 104 (18.4%) of 565 patients had arterial extravasation. Of the 104 patients, 81 (77.9%) underwent surgery, embolization, or both. The combined rate of surgery or embolization in patients with arterial extravasation was statistically higher than expected at all four institutions (p <0.001). The spleen was the most common organ injured, occurring in 277 (49.0%) of 565 patients, and arterial extravasation occurred in 49 (17.7%) of 277 patients with splenic injury. Several other visceral injuries were associated with arterial extravasation, including hepatic, renal, adrenal, and mesenteric injuries. Based on the limited reports of arterial extravasation in the nonhelical CT literature, the percentage (18%) of clinically stable patients in our study with CT scans showing arterial extravasation was higher than anticipated. This finding likely reflects the improved diagnostic capability of helical CT. Although the spleen and liver were the organs most commonly associated with arterial extravasation, radiologists should be aware that arterial extravasation may be associated with several other visceral injuries.

Pericaval fat mimicking intracaval deposits on unenhanced and contrast-enhanced helical CT in patients with cirrhosis.

The purpose of this work was to determine whether there is a significant difference in radiographic depiction of pericaval fat mimicking intracaval deposits on CT scans in patients with cirrhosis versus those without cirrhosis. The incidence of radiographic pseudolesions depicted as an intracaval fat mass identified on CT scans in 62 patients with cirrhosis was compared with that in 81 patients without cirrhosis. Pericaval fat depicted as an intracaval fat mass was identified more frequently in patients with cirrhosis (20/62, 32%) than in patients without cirrhosis (4/81, 5%), representing a statistically significant difference (p < 0.0001). A total of 24 lesions were seen in 20 patients with cirrhosis. Lesions were identified at the confluence of the hepatic veins (n = 19), below the confluence (n = 4), and above the confluence (n = 1). Pseudolesions appeared round (n = 5), oval (n = 15), or linear (n = 4). Locations included medial (n = 15), posteromedial (n = 4), anteromedial (n = 1), and posterior (n = 4). The average length was 1.5 cm. The cause of pseudolesions depicted as intracaval fat masses on CT is likely secondary to morphologic changes in the liver such as cirrhosis.

Recurrent Pyogenic Cholangitis: Efficacy of Two-Phase Helical CT

Purpose : To evaluate the usefulness of two-phase helical CT in patients with recurrent pyogenic cholangitis (RPC) for the detection of acute inflammation and assessment of the degree of portal vein (PV) stenosis as a cause of hepatic parenchymal atrophy. Materials and Methods : We retrospectively reviewed two-phase CT findings in 30 patients with RPC diagnosed by CT, ERCP (endoscopic retrograde cholangiopancreatography), and surgery. Two-phase helical CT scans were obtained 30 sec (arterial phase, AP) and 70 sec (portal phase, PP) after the start of IV administration of contrast material. Without prior information, we analyzed periductal parenchymal and ductal wall enhancement during the AP and PP, and the degree of PV stenosis during the PP. Acute inflammation was diagnosed on the basis of symptoms and laboratory findings. To evaluate the relationship between parenchymal atrophy and PV stenosis, the degree of PV stenosis in affected parenchyma was classified as one of three types (mild, 25%; moderate, 25-75%; severe, 75%), as compared with the diameter of normal PV in unaffected parenchyma. Results : Ten of the 30 patients underwent CT during the acute inflammatory stage and 20 during the remission stage. Of the ten patients with acute inflammation, eight (80%) showed transient periductal parenchymal enhancement during the AP (p0.05), which correlated closely with acute inflammation. Only three (15%) of the 20 patients with remission, however, showed transient parenchymal enhancement during this phase, at which time ductal wall enhancement was seen in three (30%) of the ten patients with acute inflammation and in seven (35%) of the 20 who showed remission (p0.05). There was no significant difference in parenchymal and ductal wall enhancement during the PP between patients with acute inflammation and those who showed remission (p0.05). Hepatic parenchymal atrophy of the lesion was seen in 24 patients. Among these, PV stenosis was mild in five (21%), moderate in 14 (58%), and severe in five (21%). Degree of PV stenosis correlated closely with severity of parenchymal atrophy during the PP. In six patients without parenchymal atrophy, PV caliber was normal. Conclusion : Our results suggest that in patients with RPC, two-phase helical CT is useful for the detection of transient periductal parenchymal enhancement accompanying acute inflammation during the AP, and for assessment of the degree of PV stenosis as a cause of hepatic parenchymal atrophy during the PP.

Unenhanced helical CT in patients with acute flank pain and renal infarction: the need for contrast material in selected cases.

Unenhanced helical CT in patients with acute flank pain and renal infarction: the need for contrast material in selected cases.G KrinskyAudio Available | Share

Detection of ureteral calculi in patients with suspected renal colic: value of reformatted noncontrast helical CT.

The purpose of this study was to determine the value of reformatted noncontrast helical CT in patients with suspected renal colic. We hoped to determine whether this technique might create images acceptable to both radiologists and clinicians and replace our current protocol of sonography and abdominal plain film. Thirty-four consecutive patients with signs and symptoms of renal colic were imaged with both noncontrast helical CT and a combination of plain film of the abdomen and renal sonography. Reformatting of the helical CT data was performed on a workstation to create a variety of reformatted displays. The correlative studies were interpreted by separate blinded observers. Clinical data, including the presence of hematuria and the documentation of stone passage or removal, were recorded. Findings on 18 CT examinations were interpreted as positive for the presence of ureteral calculi; 16 of these cases were determined to be true positives on the basis of later-documented passage of a calculus. Thirteen of the 16 cases proved to be positive were interpreted as positive for renal calculi using the combination of abdominal plain film and renal sonography. The most useful CT reformatting technique was curved planar reformatting of the ureters to determine whether a ureteral calculus was present. In this study, noncontrast helical CT was a rapid and accurate method for determining the presence of ureteral calculi causing renal colic. The reformatted views produced images similar in appearance to excretory urograms, aiding greatly in communicating with clinicians. Limitations on the technique include the time and equipment necessary for reformatting and the suboptimal quality of reformatted images when little retroperitoneal fat is present.